This document provides a summary of a training report on a 33/11 KV substation in Lucknow, India. It discusses the types of transformers used in substations, including power transformers and instrument transformers. It also describes the specifications of current transformers used at the 33/11 KV substation. Finally, it discusses some of the key components and functions of substations, including bus bars, insulators, circuit breakers, metering equipment, protection devices, and transformers.
The document discusses the key components and specifications of the 33/11 kV substation in Hajipur. It provides information on the types and ratings of transformers, circuit breakers, protective relays, insulators, bus bars, isolators, earthing systems, and capacitor banks installed at the substation. Ratings include transformers of 3 MVA capacity, 11 kV incoming and outgoing VCBs of 630A and 800A capacity, and a 160 MVA main bus bar rating. The substation receives high voltage electricity from generating stations and lowers the voltage for local distribution.
This document provides an introduction and overview of a 33/11 kV substation in Uttar Pradesh, India. It discusses the key components of the substation including transformers, circuit breakers, insulators, and earthing systems. The substation steps down power from 33 kV to 11 kV and distributes it to nearby areas. Earthing is an important consideration in substation design for safety and preventing potential gradients. Transformers, circuit breakers, and other equipment are discussed in terms of their functions and specifications at this particular substation.
This document provides an introduction and overview of a 33/11 kV substation in Uttar Pradesh, India. It discusses the key components of the substation including transformers, circuit breakers, insulators, protective equipment. It also covers the types of substations, earthing design methodology, and materials used for earthing. The document aims to provide training on the design, components and operation of electrical substations.
Ishank Ranjan completed an industrial training project at the 220kV Grid Transmission Substation in Naubasta, Kanpur. The report acknowledges the contributions of staff at the substation who helped explain the various equipment. It includes sections on the components used at grid transmission substations such as conductors, transformers, capacitor banks, isolators, circuit breakers and lightning arresters. The report provides details on the panel section which contains control and protection panels, and the substation yard layout.
This document provides a 3-page summer internship report submitted by Asafak Husain to Prof. S.P. Srivastava of IIT Roorkee. The report summarizes Husain's 45-day internship at the 220kV GSS RRVPNL substation in Ajmer, Rajasthan, where he learned about the operation and equipment of the substation. Key points covered in the report include the types and functions of equipment like transformers, relays, circuit breakers, capacitors, and the roles they play in transmitting and distributing electrical power safely and efficiently.
- The document provides details of a 132kV grid station project in Rawalpindi for Islamabad Electric Supply Company, including scope of work, contract values, equipment installed, civil works completed, and diagrams of the site layout, single line diagram, and protection relay circuits. Key equipment installed includes two 31.5/40MVA power transformers, four 132kV circuit breakers, disconnect switches, current and potential transformers, and indoor panels. Civil works included foundations, trenches, roads, fencing and a control house building. Diagrams show the layout and protection schemes.
Engineering Final Year Project Report on "Electrical Safety and Protection of...Pratap Bhunia
Substation Network and Load Distribution
Substation Network Design
Civil Works Specification
Various Subsystems in Substation and Their Functions
Substation Equipment and Their Functions
Design of Capacity of Transmission Lines
Calculation of Line Constants and SIL
Bus Bar Arrangement
Power Transformer
Substation Earthing
Circuit Breaker
Isolator
Current Transformer
Capacitor Voltage Transformer
Lightning Surge
Switching Surge
Lightning Arrester
Surge Absorber
The document discusses the 33/11 kV substation in Indiranagar, Lucknow. Key details include:
1) The substation receives power at 33kV from the main grid and contains transformers that step down the voltage to 11kV.
2) It has a total transformer capacity of 160MVA split between four transformers connected in parallel.
3) The substation contains equipment like circuit breakers, current transformers, lightning arrestors to monitor and regulate power flow.
4) Power is distributed from the substation through six 33kV feeders and multiple 11kV feeders to the surrounding Indiranagar area.
The document discusses the key components and specifications of the 33/11 kV substation in Hajipur. It provides information on the types and ratings of transformers, circuit breakers, protective relays, insulators, bus bars, isolators, earthing systems, and capacitor banks installed at the substation. Ratings include transformers of 3 MVA capacity, 11 kV incoming and outgoing VCBs of 630A and 800A capacity, and a 160 MVA main bus bar rating. The substation receives high voltage electricity from generating stations and lowers the voltage for local distribution.
This document provides an introduction and overview of a 33/11 kV substation in Uttar Pradesh, India. It discusses the key components of the substation including transformers, circuit breakers, insulators, and earthing systems. The substation steps down power from 33 kV to 11 kV and distributes it to nearby areas. Earthing is an important consideration in substation design for safety and preventing potential gradients. Transformers, circuit breakers, and other equipment are discussed in terms of their functions and specifications at this particular substation.
This document provides an introduction and overview of a 33/11 kV substation in Uttar Pradesh, India. It discusses the key components of the substation including transformers, circuit breakers, insulators, protective equipment. It also covers the types of substations, earthing design methodology, and materials used for earthing. The document aims to provide training on the design, components and operation of electrical substations.
Ishank Ranjan completed an industrial training project at the 220kV Grid Transmission Substation in Naubasta, Kanpur. The report acknowledges the contributions of staff at the substation who helped explain the various equipment. It includes sections on the components used at grid transmission substations such as conductors, transformers, capacitor banks, isolators, circuit breakers and lightning arresters. The report provides details on the panel section which contains control and protection panels, and the substation yard layout.
This document provides a 3-page summer internship report submitted by Asafak Husain to Prof. S.P. Srivastava of IIT Roorkee. The report summarizes Husain's 45-day internship at the 220kV GSS RRVPNL substation in Ajmer, Rajasthan, where he learned about the operation and equipment of the substation. Key points covered in the report include the types and functions of equipment like transformers, relays, circuit breakers, capacitors, and the roles they play in transmitting and distributing electrical power safely and efficiently.
- The document provides details of a 132kV grid station project in Rawalpindi for Islamabad Electric Supply Company, including scope of work, contract values, equipment installed, civil works completed, and diagrams of the site layout, single line diagram, and protection relay circuits. Key equipment installed includes two 31.5/40MVA power transformers, four 132kV circuit breakers, disconnect switches, current and potential transformers, and indoor panels. Civil works included foundations, trenches, roads, fencing and a control house building. Diagrams show the layout and protection schemes.
Engineering Final Year Project Report on "Electrical Safety and Protection of...Pratap Bhunia
Substation Network and Load Distribution
Substation Network Design
Civil Works Specification
Various Subsystems in Substation and Their Functions
Substation Equipment and Their Functions
Design of Capacity of Transmission Lines
Calculation of Line Constants and SIL
Bus Bar Arrangement
Power Transformer
Substation Earthing
Circuit Breaker
Isolator
Current Transformer
Capacitor Voltage Transformer
Lightning Surge
Switching Surge
Lightning Arrester
Surge Absorber
The document discusses the 33/11 kV substation in Indiranagar, Lucknow. Key details include:
1) The substation receives power at 33kV from the main grid and contains transformers that step down the voltage to 11kV.
2) It has a total transformer capacity of 160MVA split between four transformers connected in parallel.
3) The substation contains equipment like circuit breakers, current transformers, lightning arrestors to monitor and regulate power flow.
4) Power is distributed from the substation through six 33kV feeders and multiple 11kV feeders to the surrounding Indiranagar area.
Kamal final presentation eee reb- comillasiam hossain
This presentation provides an overview of the operation of a 33/11 KV substation at Comilla Palli Bidyut Samity-1. It discusses the organizational background, objectives, basic electrical systems, distribution systems, types of substations, transformers, isolators, insulators, fuses, circuit breakers, and relays used. Diagrams and specifications are provided for various equipment including power transformers, distribution transformers, current transformers, potential transformers, isolators, fuses, circuit breakers and relays.
Multilevel inverter fed induction motor driveseSAT Journals
Abstract Induction motor drive is used in almost all industries including oil and gas sectors, production plants and process industries. Speed control of induction motor is a major concern. The proposed technology implements a better speed control for induction motor drives using a multilevel inverter. The switching sequences are generated by optimized pre-calculated angles for controlling induction motor. And also with the use of a multi-level inverter there is lower distortion of output voltages and Total Harmonic Distortion (THD) of machine currents under steady state operating conditions can be minimized. THD can be further reduced by optimizing the switching angles. This technology can be extended to higher levels of output voltages by using an n state multilevel inverter. In this paper, a seven level multilevel inverter is proposed, its simulation is done in MATLAB/Simulink and the results were verified by experimenting on a hardware prototype. This could be extended to higher levels of voltage waveform and can be used in photovoltaics. A multilevel inverter could be a better choice as a dc-dc converter in solar power circuits. Keywords: Multilevel inverter, optimal pulse with modulation, total harmonic d1istortion.
This document provides a report on the 400/220 KV Nelamangala power station near Bangalore, India. It includes a single line diagram of the substation, details of the bus bar scheme, and descriptions of the main equipment including capacitive voltage transformers, current transformers, circuit breakers, isolators, transformers, and reactors. It also covers substation auxiliaries, control rooms, earthing systems, and provides specifications for the main transformers. The power station was established to integrate new power sources into the southern grid and reduce grid failures in the region.
PPT ON SUMMER VOCATIONAL TRAINING ON 132/33 KV AT MOHADDIPUR, SUB-STATION, GO...Abrar Ahmad
IT PRESENTATION IS USEFUL FOR ENGINEERING STUDENTS OF B.TECH.WHICH IS STUDYING IN ALL ENGINEERING COLLEGES FOR VARIOUS STREAMS FIRST OF ALL IS ELECTRICAL ENGINEERING AND THEY ARE DOING SUMMER TRAINING BETWEEN 3RD YEAR TO 4TH YEAR.
The document provides a typical list of materials required for construction of a 132 kV grid substation, including:
1. Various types of structures/beams, outdoor equipment like transformers, isolators, circuit breakers, current/potential transformers, lightning arresters, post insulators.
2. Control room equipment such as different voltage control and relay panels, battery sets, chargers, distribution boards.
3. Bus bar materials like hardware for single zebra and panther conductors, disc insulators.
The list covers common equipment but is not exhaustive, as additional items may be needed depending on the specific substation layout and requirements. It is intended to aid planning for substation construction projects.
NTDC 220kV Transmission gird station Internship reportAneel-k Suthar
This document provides an overview of Anil Kumar's internship report on the 220/132 kV grid station in Jamshoro-T.M. Khan Road. It includes acknowledgements, an executive summary, and sections on the grid station, one-line diagram, bus bar, switches, relays, transformers, and maintenance. The grid station regulates and controls power flow and supplies electricity to substations. It uses a double bus one and a half breaker scheme, which improves reliability over other schemes by allowing maintenance without power interruptions.
Automatic load sharing of transformer using microcontrollerPrakhar Anand
1. ABSTRACT:-
The transformer is a static device, which converts power from one level to another level.
The main aim is to protect the transformer under overload condition by load sharing.
Due to overload on transformer, the efficiency drops and windings get overheated and may get burnt.
Thus by sharing load on transformer, the transformer is protected. This will be done by connecting another transformer in parallel through a micro-controller.
The micro controller compares the load on the first transformer with a reference value. When the load exceeds the reference value, the second transformer will share the extra load.
Therefore, the two transformer work efficiently and damage is prevented. Main modules used here are sensing unit, control unit and micro-control.
A GSM modem is also used to inform the control station about switching.
The advantages of the project are transformer protection, uninterrupted power supply, and short circuit protection.
2. OBJECTIVE:-
To design & fabrication of a hardware which will monitor the performance of the load sharing process by taking power consumed by the load into consideration.
3. INTRODUCTION:-
Transformer is the vital component in the electric power transmission and distribution system.
The problems of overloading, voltage variation and heating effects are very common. It takes a lot of time for its repair and also involves lot of expenditure.
This work is all about protecting the transformer under overload condition. Due to overload the efficiency drops and the secondary winding gets overheated or it may be burnt.
So, by reducing the extra load, the transformer can be protected. This can be done by operating another transformer in parallel with main transformer through microcontroller and change over relay.
The microcontroller compares the load on the first transformer with a reference value. When the load exceeds the reference value, the slave transformer will automatically be connected in parallel with first transformer and share the extra load.
Therefore, a number of transformers work efficiently under overload condition and the damage can be prevented.
In this work, the slave transformers share the load of master transformer in the case of over load and over temperature conditions.
A sensor circuit containing microcontroller, current transformer etc. is designed to log the data from master transformer and if it is found to be in overload condition, immediately the slave transformer will be connected in the parallel to the master transformer and the load is shared.
The document is a presentation on the Liluah 132/33/25 KV substation in West Bengal. It includes acknowledgments, a single line diagram of the substation, and sections covering various equipment found at the substation like electrical busbars, protective relay schemes, lightning protection, isolators, capacitor banks, powerline carrier communication, batteries, earth transformers, traction transformers, station service transformers, and power transformers. Technical specifications are provided for some of the major equipment.
H bridge multilevel inverter organized krunal gamit
This document certifies that two students, Patel Vinalkumar I. and Gamit Krunalbhai H., completed a project on an H-Bridge Multilevel Inverter under the guidance of Smt S.J. Pandav. The project report discusses the design and implementation of a new topology for a single-phase five-level cascaded H-bridge multilevel inverter using only five switches and two DC power sources. Various switching topologies are analyzed and modulation techniques are proposed to minimize total harmonic distortion and improve output voltage. Simulation results show the new topology reduces harmonics and switches compared to conventional methods.
This simulation summarizes a student's bachelor's thesis on solid state transformers using cascaded H-bridge converters. It describes a proposed 20kVA cascaded H-bridge converter based solid state transformer connecting to a 12kV distribution system. Key components include a cascaded AC/DC rectifier, dual active bridge converters with high frequency transformers, and a DC/AC inverter. The simulation models this design in NI Multisim, using IGBT switches and various control circuits to regulate the voltage and power flow between the primary and secondary sides. Simulation results demonstrate voltage regulation through phase control of the rectifiers and output voltage control of the SPWM inverters.
This document is an internship training report submitted by Muhammad Usman Rafiq to the Department of P&I at IESCO in partial fulfillment of the requirements for a one month internship. The report provides an overview of the equipment used at a 132kv grid substation, including transformers, circuit breakers, bus couplers, incoming and outgoing panels, and batteries/battery chargers. It discusses the components and functions of these devices. The report is dedicated to Usman Rafiq's parents and teachers for their support and includes certificates, acknowledgments, and abstract sections.
Distribution and Load Sharing of Transformer Automatically by using Microcont...IRJET Journal
This document describes a system for automatically distributing load and sharing load between transformers using a microcontroller. The system monitors the load on the main transformer and connects additional transformers in parallel when the load exceeds the rating of the main transformer to prevent overloading. It uses current transformers to sense the load, a microcontroller to compare the load to a threshold and control relays, and relays to connect additional transformers as needed. When the load is heavy, the second transformer connects to help share the extra load, and a third transformer can connect if needed. The system aims to protect transformers from overloading and overheating while providing uninterrupted power by automatically distributing the load across multiple transformers.
This document provides a report on the 220KV/66KV New Receiving Station substation. It includes a single line diagram, power flow chart, descriptions of the main equipment including transformers, circuit breakers, batteries, control room, and earthing systems. The substation handles about 3 million units per day with a peak load of 176MW. It receives power at 220KV and steps it down to 66KV and 11KV to feed local distribution.
The document summarizes a presentation on vocational training provided by CSPDCL. It discusses the training location and dates, supervisor, and topics covered including substation equipment, types of transformers, circuit breakers, busbars, fuses, and protection schemes. It also reviews maintenance procedures for transformers, circuit breakers, isolators, and discusses capacitor banks for power factor improvement.
An Improved DTFC based Five Levels - NPC Inverter Fed Induction Motor for Tor...IJPEDS-IAES
This paper presents a five level Neutral Point Clamped (NPC) inverter fed
IM (Induction Motor) drive for variable speed application. In general the
stator current is very highly affected by the harmonic components. It can be
affecting the torque to produce high torque ripple in IM at maximum to low
speed region. Since the drive performances are depends on mathematical
model contains the parameters variations, noise, common mode voltage, flux
variation and harmonic levels of the machine. Torque ripples and voltage
saturations are the most significant problems in drive application. To
overcome this problem the DTFC (direct torque and flux control) technique
based five-level neutral-point-clamped (NPC-5L) approach is used. The
proposed control scheme uses to stator current error as variable. Through the
resistance estimated PI controller rules based the selection of voltage space
vector modulation technique is optimized and motor performance level has
been improved. The torque & speed are successfully controlled with less
torque response. The results are compared and verified with conventional
three phases VSI under different control technique by Matlab/Simulink.
three level diode clamp inverter. that converts any type of DC ( rectified, PV cell, battery etc.) to AC supply. we made by mosfet and ardiuno . in this ppt we present the Simulink model of a three-level inverter and the hardware presentation of the inverter.
This document provides an overview of a presentation on a summer training at a 132/33 kV sub-station in Allahabad, India. It discusses key equipment used in sub-stations including transformers, protection devices like Buchholz relays and silica gel breathers, cooling equipment, and other critical infrastructure like circuit breakers, capacitor banks, potential and current transformers, isolators, and insulators. It also describes the functions of this equipment and why they are important components of the power distribution system.
This document summarizes a training at a 33/11 kV distribution substation. It describes the substation's components including incoming and outgoing lines, isolators, vacuum circuit breakers, busbars, transformers, current transformers, potential transformers, and earthing system. It also discusses the control room, safety procedures, and technical and non-technical skills learned during the training, such as maintenance, management, and proper work procedures. The conclusion states that the training increased understanding of how electricity is transmitted and the substation system.
This document is a summer training report submitted to the National Power Training Institute and Maharishi Dayanand University. It details a project conducted with the Uttrakhand Jal Vidyut Nigam Limited to calculate the aggregate technical and commercial losses of the Dakpathar Distribution Division and make recommendations to strengthen and upgrade the division. The report finds the AT&C losses of the division to be 50.83%, which is very high. It analyzes reasons for the high losses including inadequate infrastructure, lack of metering, illegal connections, and issues with billing and record keeping. Recommendations are provided to install meters, improve infrastructure, enforce policies for employee housing, pursue timely billing and collection, and increase investments to reduce
This document summarizes a summer training report analyzing aggregate technical and commercial (AT&C) losses in the Dakpathar Distribution Division (DDD) of Uttrakhand Jal Vidyut Nigam Limited (UJVNL). The report determines DDD's current AT&C loss is 50.83%, which is very high compared to the national average of 24.15%. Several factors contribute to the high loss, including inadequate infrastructure, lack of meters, illegal connections, and billing/collection inefficiencies. The report provides recommendations to reduce losses such as improving employee tracking, replacing lines to prevent theft, installing meters, collecting fees for excess usage, and improving billing practices. Implementing these recommendations could reduce D
Kamal final presentation eee reb- comillasiam hossain
This presentation provides an overview of the operation of a 33/11 KV substation at Comilla Palli Bidyut Samity-1. It discusses the organizational background, objectives, basic electrical systems, distribution systems, types of substations, transformers, isolators, insulators, fuses, circuit breakers, and relays used. Diagrams and specifications are provided for various equipment including power transformers, distribution transformers, current transformers, potential transformers, isolators, fuses, circuit breakers and relays.
Multilevel inverter fed induction motor driveseSAT Journals
Abstract Induction motor drive is used in almost all industries including oil and gas sectors, production plants and process industries. Speed control of induction motor is a major concern. The proposed technology implements a better speed control for induction motor drives using a multilevel inverter. The switching sequences are generated by optimized pre-calculated angles for controlling induction motor. And also with the use of a multi-level inverter there is lower distortion of output voltages and Total Harmonic Distortion (THD) of machine currents under steady state operating conditions can be minimized. THD can be further reduced by optimizing the switching angles. This technology can be extended to higher levels of output voltages by using an n state multilevel inverter. In this paper, a seven level multilevel inverter is proposed, its simulation is done in MATLAB/Simulink and the results were verified by experimenting on a hardware prototype. This could be extended to higher levels of voltage waveform and can be used in photovoltaics. A multilevel inverter could be a better choice as a dc-dc converter in solar power circuits. Keywords: Multilevel inverter, optimal pulse with modulation, total harmonic d1istortion.
This document provides a report on the 400/220 KV Nelamangala power station near Bangalore, India. It includes a single line diagram of the substation, details of the bus bar scheme, and descriptions of the main equipment including capacitive voltage transformers, current transformers, circuit breakers, isolators, transformers, and reactors. It also covers substation auxiliaries, control rooms, earthing systems, and provides specifications for the main transformers. The power station was established to integrate new power sources into the southern grid and reduce grid failures in the region.
PPT ON SUMMER VOCATIONAL TRAINING ON 132/33 KV AT MOHADDIPUR, SUB-STATION, GO...Abrar Ahmad
IT PRESENTATION IS USEFUL FOR ENGINEERING STUDENTS OF B.TECH.WHICH IS STUDYING IN ALL ENGINEERING COLLEGES FOR VARIOUS STREAMS FIRST OF ALL IS ELECTRICAL ENGINEERING AND THEY ARE DOING SUMMER TRAINING BETWEEN 3RD YEAR TO 4TH YEAR.
The document provides a typical list of materials required for construction of a 132 kV grid substation, including:
1. Various types of structures/beams, outdoor equipment like transformers, isolators, circuit breakers, current/potential transformers, lightning arresters, post insulators.
2. Control room equipment such as different voltage control and relay panels, battery sets, chargers, distribution boards.
3. Bus bar materials like hardware for single zebra and panther conductors, disc insulators.
The list covers common equipment but is not exhaustive, as additional items may be needed depending on the specific substation layout and requirements. It is intended to aid planning for substation construction projects.
NTDC 220kV Transmission gird station Internship reportAneel-k Suthar
This document provides an overview of Anil Kumar's internship report on the 220/132 kV grid station in Jamshoro-T.M. Khan Road. It includes acknowledgements, an executive summary, and sections on the grid station, one-line diagram, bus bar, switches, relays, transformers, and maintenance. The grid station regulates and controls power flow and supplies electricity to substations. It uses a double bus one and a half breaker scheme, which improves reliability over other schemes by allowing maintenance without power interruptions.
Automatic load sharing of transformer using microcontrollerPrakhar Anand
1. ABSTRACT:-
The transformer is a static device, which converts power from one level to another level.
The main aim is to protect the transformer under overload condition by load sharing.
Due to overload on transformer, the efficiency drops and windings get overheated and may get burnt.
Thus by sharing load on transformer, the transformer is protected. This will be done by connecting another transformer in parallel through a micro-controller.
The micro controller compares the load on the first transformer with a reference value. When the load exceeds the reference value, the second transformer will share the extra load.
Therefore, the two transformer work efficiently and damage is prevented. Main modules used here are sensing unit, control unit and micro-control.
A GSM modem is also used to inform the control station about switching.
The advantages of the project are transformer protection, uninterrupted power supply, and short circuit protection.
2. OBJECTIVE:-
To design & fabrication of a hardware which will monitor the performance of the load sharing process by taking power consumed by the load into consideration.
3. INTRODUCTION:-
Transformer is the vital component in the electric power transmission and distribution system.
The problems of overloading, voltage variation and heating effects are very common. It takes a lot of time for its repair and also involves lot of expenditure.
This work is all about protecting the transformer under overload condition. Due to overload the efficiency drops and the secondary winding gets overheated or it may be burnt.
So, by reducing the extra load, the transformer can be protected. This can be done by operating another transformer in parallel with main transformer through microcontroller and change over relay.
The microcontroller compares the load on the first transformer with a reference value. When the load exceeds the reference value, the slave transformer will automatically be connected in parallel with first transformer and share the extra load.
Therefore, a number of transformers work efficiently under overload condition and the damage can be prevented.
In this work, the slave transformers share the load of master transformer in the case of over load and over temperature conditions.
A sensor circuit containing microcontroller, current transformer etc. is designed to log the data from master transformer and if it is found to be in overload condition, immediately the slave transformer will be connected in the parallel to the master transformer and the load is shared.
The document is a presentation on the Liluah 132/33/25 KV substation in West Bengal. It includes acknowledgments, a single line diagram of the substation, and sections covering various equipment found at the substation like electrical busbars, protective relay schemes, lightning protection, isolators, capacitor banks, powerline carrier communication, batteries, earth transformers, traction transformers, station service transformers, and power transformers. Technical specifications are provided for some of the major equipment.
H bridge multilevel inverter organized krunal gamit
This document certifies that two students, Patel Vinalkumar I. and Gamit Krunalbhai H., completed a project on an H-Bridge Multilevel Inverter under the guidance of Smt S.J. Pandav. The project report discusses the design and implementation of a new topology for a single-phase five-level cascaded H-bridge multilevel inverter using only five switches and two DC power sources. Various switching topologies are analyzed and modulation techniques are proposed to minimize total harmonic distortion and improve output voltage. Simulation results show the new topology reduces harmonics and switches compared to conventional methods.
This simulation summarizes a student's bachelor's thesis on solid state transformers using cascaded H-bridge converters. It describes a proposed 20kVA cascaded H-bridge converter based solid state transformer connecting to a 12kV distribution system. Key components include a cascaded AC/DC rectifier, dual active bridge converters with high frequency transformers, and a DC/AC inverter. The simulation models this design in NI Multisim, using IGBT switches and various control circuits to regulate the voltage and power flow between the primary and secondary sides. Simulation results demonstrate voltage regulation through phase control of the rectifiers and output voltage control of the SPWM inverters.
This document is an internship training report submitted by Muhammad Usman Rafiq to the Department of P&I at IESCO in partial fulfillment of the requirements for a one month internship. The report provides an overview of the equipment used at a 132kv grid substation, including transformers, circuit breakers, bus couplers, incoming and outgoing panels, and batteries/battery chargers. It discusses the components and functions of these devices. The report is dedicated to Usman Rafiq's parents and teachers for their support and includes certificates, acknowledgments, and abstract sections.
Distribution and Load Sharing of Transformer Automatically by using Microcont...IRJET Journal
This document describes a system for automatically distributing load and sharing load between transformers using a microcontroller. The system monitors the load on the main transformer and connects additional transformers in parallel when the load exceeds the rating of the main transformer to prevent overloading. It uses current transformers to sense the load, a microcontroller to compare the load to a threshold and control relays, and relays to connect additional transformers as needed. When the load is heavy, the second transformer connects to help share the extra load, and a third transformer can connect if needed. The system aims to protect transformers from overloading and overheating while providing uninterrupted power by automatically distributing the load across multiple transformers.
This document provides a report on the 220KV/66KV New Receiving Station substation. It includes a single line diagram, power flow chart, descriptions of the main equipment including transformers, circuit breakers, batteries, control room, and earthing systems. The substation handles about 3 million units per day with a peak load of 176MW. It receives power at 220KV and steps it down to 66KV and 11KV to feed local distribution.
The document summarizes a presentation on vocational training provided by CSPDCL. It discusses the training location and dates, supervisor, and topics covered including substation equipment, types of transformers, circuit breakers, busbars, fuses, and protection schemes. It also reviews maintenance procedures for transformers, circuit breakers, isolators, and discusses capacitor banks for power factor improvement.
An Improved DTFC based Five Levels - NPC Inverter Fed Induction Motor for Tor...IJPEDS-IAES
This paper presents a five level Neutral Point Clamped (NPC) inverter fed
IM (Induction Motor) drive for variable speed application. In general the
stator current is very highly affected by the harmonic components. It can be
affecting the torque to produce high torque ripple in IM at maximum to low
speed region. Since the drive performances are depends on mathematical
model contains the parameters variations, noise, common mode voltage, flux
variation and harmonic levels of the machine. Torque ripples and voltage
saturations are the most significant problems in drive application. To
overcome this problem the DTFC (direct torque and flux control) technique
based five-level neutral-point-clamped (NPC-5L) approach is used. The
proposed control scheme uses to stator current error as variable. Through the
resistance estimated PI controller rules based the selection of voltage space
vector modulation technique is optimized and motor performance level has
been improved. The torque & speed are successfully controlled with less
torque response. The results are compared and verified with conventional
three phases VSI under different control technique by Matlab/Simulink.
three level diode clamp inverter. that converts any type of DC ( rectified, PV cell, battery etc.) to AC supply. we made by mosfet and ardiuno . in this ppt we present the Simulink model of a three-level inverter and the hardware presentation of the inverter.
This document provides an overview of a presentation on a summer training at a 132/33 kV sub-station in Allahabad, India. It discusses key equipment used in sub-stations including transformers, protection devices like Buchholz relays and silica gel breathers, cooling equipment, and other critical infrastructure like circuit breakers, capacitor banks, potential and current transformers, isolators, and insulators. It also describes the functions of this equipment and why they are important components of the power distribution system.
This document summarizes a training at a 33/11 kV distribution substation. It describes the substation's components including incoming and outgoing lines, isolators, vacuum circuit breakers, busbars, transformers, current transformers, potential transformers, and earthing system. It also discusses the control room, safety procedures, and technical and non-technical skills learned during the training, such as maintenance, management, and proper work procedures. The conclusion states that the training increased understanding of how electricity is transmitted and the substation system.
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1. A
TRAINING
REPORT ON
UTTAR PRADESH POWER CORPORATION LIMITED
33/11 KV SUBSTATION INDIRANAGAR SECTOR-25,
LUCKNOW(UTTAR PRADESH).
A
training Report Submitted
In Partial Fulfillment of the Requirements
for the award of Degree of
Bachelor of Technology
In
Electrical & Electronics Engineering
By
Prateek Agarwal
BABU BANARASI DAS NORTHERN INDIA INSTITUTE OF
TECHNOLOGY, LUCKNOW
2. Table of contents
ACKNOWLEDGEMENT i
LIST OF FIGURES ii
1. Introduction 1-2
1.1 About 33/11 KV substation Indiranagar,Lucknow 1
2. Transformers 3-5
2.1 Types of Transformers 3-5
2.1.1 Power transformer 4
2.1.2 Instrument transformer 4
2.1.3 Autotransformer 5
2.1.4 On the basis of working 5
2.1.5 On the basis of structure 5
3. Specification of C.T. used in 33/11 KV substation Sector-25,Indranagar 6
4. Substation 7-13
4.1 Types of substation 8
4.1.1 According to the service requirement 8
4.1.2 According to the constructional features 8
4.2 Substation characteristics 10
4.3 Steps in designing substation 10
4.3.1 Earthing and bonding 10
4.3.2 Substation earthing calculation methodology 11
4.3.3 Earthing material 11
4.3.4 Switch yard fence earthing 12
3. 4.4 Conductors used in substation designing 12
5. Chronological training diary 14-17
5.1 Power line carrier communication(PLCC) 14
5.1.1 Applications 14
5.2 Principle of PLCC 15
5.2.1 Wave trap or line trap 15
5.2.2 Coupling capacitor 16
5.2.3 Protective device of coarse voltage arrester 16
5.2.4 Coupling of filter 16
5.2.5 H.F. cable 16
6. Bus bars 18-19
7. Insulators 20-25
7.1 Circuit breakers 21
7.2 Oil circuit breaker 22
7.3 Air blast circuit breaker 22
7.4 Sulphar hexafluoride circuit breaker (SF6) circuit breaker 23
7.5 Vacuum circuit breaker 24
8. Metering and Indication equipment 26-29
8.1 Relay 26
8.2 Relays used in control panel of substation 27
8.2.1 Differential relay 27
8.2.2 Over current relay 27
8.2.3 Directional relay 28
5. ACKNOWLEDGEMENT
Training has an important role in exposing the real life situation in an industry. It was a
great experience for me to work on training at UTTAR PRADESH POWER COOPERATION
LIMITED through which I could learn how to work in a professional environment.
Now, I would like to thank the people who guided me and have been a constant source of
inspiration throughout the tenure of my summer training.
I am sincerely grateful to MR. V.R. VERMA (Sub Divisional Officer) at 33/11 KV
substation, INDIRANAGAR SECTOR-25 who rendered me his valuable assistance, constant
encouragement and able guidance which made this training actually possible.
I wish my deep sense of gratitude to MR. S.N. PATEL (Junior Engineer) whose
affectionate guidance has enabled me to complete this training successfully. I also wish my deep
sense of gratitude to MR. ANIL SINGH RATHODE(HOD: EN Department) and my
project guide MR. PRABHAT CHANDRA SRIVASTAVA and other faculty members
whose guidance and encouragement made my training successful.
PRATEEK AGARWAL
6. List of figures
Figure no. Name of figure Page no.
Figure 1.1 33/11 KV Substation Indiranagar 1
Figure 2.1 Transformer 3
Figure 2.2 Power transformer 4
Figure 2.3 Instrument transformer 4
Figure 2.4 Auto transformer 5
Figure 2.5 Core type 5
Figure 2.6 Shell type 5
Figure 3.1 Current transformer 6
Figure 4.1 View of substation 7
Figure 4.2 Transformer substation 8
Figure 5.1 Power line carrier communication (PLCC) 14
Figure 6.1 Typical representation of bus bars 18
Figure 7.1 Insulators used in substation 20
Figure 7.2 Circuit breaker arrangements 21
Figure 7.3 Oil circuit breaker 22
Figure 7.4 Air blast circuit breaker 23
Figure 7.5 SF6 Circuit breaker 23
Figure 7.6 Vacuum circuit breaker 24
Figure 8.1 Typical view of Relay 26
Figure 8.2 Differential Relay 27
Figure 8.3 Over current Relay 27
Figure 8.4 Directional Relay 28
Figure 8.5 Tripping Relay 28
Figure 8.6 Auxiliary Relay 29
Figure 9.1 Capacitor bank 30
Figure 9.2 Substation fuse 31
Figure 9.3 Bus coupler 31
7. 1. INTRODUCTION
The creation of Uttar Pradesh Power Corporation Ltd. (UPPCL) on January 14,
2000 is the result of power sector reforms and restructuring in UP (India) which is the focal point
of the Power Sector, responsible for planning and managing the sector through its transmission,
distribution and supply of electricity.
UPPCL will be professionally managed utility supplying reliable and cost efficient
electricity to every citizen of the state through highly motivated employees and state of art
technologies, providing an economic return to our owners and maintaining leadership in the
country.
We shall achieve this being a dynamic, forward looking, reliable, safe and trustworthy
organization, sensitive to our customers interests, profitable and sustainable in the long run,
providing uninterrupted supply of quality power, with transparency and integrity in operation
1.1 ABOUT 33/11KV SUBSTATION INDIRANAGAR
Figure 1.1 33/11KV Substation Indiranagar
8. The main bus 33KV is connected to grid located at Sector-25, INDIRANAGAR,
LUCKNOW. Now the transmission line first parallel connected with lightning arrester to
diverge surge, followed by CVT connected parallel. CVT measures voltage and steeps down at
110V. A.C. for control panel, at the location a wave trap is connected to carrier communication
at higher frequencies. A current transformer is connected in series with line which measure
current and step down current at ratio 800:1 for control panel.
Switchgear equipment is provided, which is the combination of a circuit breaker having
an isolator at each end. A transformer is connected to main bus though a bus coupler. The main
bus has total capability of 160 MVA for 33 KV, which is subdivided into two transformer
capacity of 80 MVA (40MVA+40MVA) parallel connected for 33KV and other two transformer
capacity of 80KV (40KV+40KV) are parallel connected for substation.
At both ends of transformer lightning arrester current transformer and switchgear
equipment provided. Transformer step downs voltage from 220KV to 33KV. The main bus is
provided with switchgear equipment & a current transformer. This gives way to six feeders
transmitting power to INDRA NAGAR. The main bus is connected to jack bus or transfer bus
through a bus coupler & 11KV is provided with switchgear equipment. This gives way to feeders
transmitting power to Sector-25, Bhoot Nath, Munshi Pulia, Ring Road and Sarvoday
Nagar.
A step down transformer of 11KV/440V is connected to control panel to provide supply
to the equipments of the substation. Capacitor bank is connected to main bus of 11KV. It is
provided to improve power factor & voltage profile.
9. 2. TRANSFORMERS
Figure: 2.1 Transformer
Transformer is a static machine, which transforms the potential of alternating current at
same frequency. It means the transformer transforms the low voltage into high voltage & high
voltage to low voltage at same frequency. It works on the principle of static induction principle.
When the energy is transformed into a higher voltage, the transformer is called step up
transformer but in case of other is known as step down transformer.
2.1 TYPES OF TRANSFORMER
2.1.1 Power transformer
2.1.2 Instrument transformer
2.1.3 Auto transformer
2.1.4 On the basis of working
2.1.5 On the basis of structure
10. 2.1.1 POWER TRANSFORMER:
Figure 2.2 Power Transformers
Types of power transformer:
2.1.1.1 Single phase transformer
2.1.1.2 Three phase transformer
2.1.2 INSTRUMENT TRANSFORMER:
Fig: 2.3 Instrument Transformers
a) Current transformer
b) Potential transformer
11. 2.1.3 AUTO TRANSFORMER:
Fig 2.4 Auto Transformer
a) Single phase transformer
b) Three phase transformer
2.1.4 ON THE BASIS OF WORKING
2.1.4.1 Step down: Converts high voltage into low voltage.
2.1.4.2 Step up: Converts low voltage into high voltage.
2.1.5 ON THE BASIS OF STRUCTURE
Figure 2.5 core type Figure 2.6 Shell type
12. 3. SPECIFICATION OF C.T. USED IN 33/11 KV SUB STATION,
INDIRANAGAR,LUCKNOW
Figure 3.1 Current transformer
3.1 Standard: IS-2785
3.2 Highest System Voltage: 145 KV
3.3 Frequency: 50Hz
3.4 C.T. Current: 25 KA/1Sec.
3.5 Rated primary current: 800 Ampere
13. 4. SUBSTATIONS
Figure 4.1 View of substation
The present day electrical power system is A.C.i.e. electrical power is generated,
transmitted & distributed in the form of the alternating current. The electric power is produced at
power plant stations which are located at favorable places generally quite away from the
consumers. It is delivered to the consumers through a large network of transmission 7
distribution.
At many places in the power system, it may be desirable and necessary to change some
characteristics e.g. voltage, ac to dc, frequency, power factor etc. of electric supply. This
accomplished by suitable apparatus called substation. For example; generation voltage (11 KV or
33 KV) at the power station is set up to high voltage (say 220 KV or 132 KV) for transmission of
electric power. The assembly of apparatus (e.g. transformer etc.) used for this purpose in the
substation. Similarly near the consumer’s localities, the voltage may have to be step down to
utilization level. This job is again accomplished by suitable apparatus called substation.
The assembly of apparatus to change some characteristic of electric power supply is
called substation.
The two most ways to classify substation are:-
14. 4.1 TYPES OF SUBSTATION
4.1.1 According to the service requirement:
4.1.1.1 Transformer substation
4.1.1.2 Switch substation
4.1.1.3 Power factor correction substation
4.1.1.4 Frequency change substation
4.1.1.5 Converting substation
4.1.1.6 Industrial substation
4.1.2 According to the constructional features:
4.1.2.1 Indoor substation
4.1.2.3 Outdoor substation
4.1.2.4 Underground substation
4.1.2.5 Pole mounted substation
4.1.1.1 TRANSFORMER SUBSTATION
Figure 4.2 Transformer substation
They are known as transformer substations as because transformer is the main
component employed to change the voltage level, depending upon the purposed served
15. transformer substations may be classified into:
4.1.1.1.1 STEP UP SUBSTATION
The generation voltage is steeped up to high voltage to affect economy in
transmission of electric power. These are generally located in the power houses and are
of outdoor type.
4.1.1.1.2 PRIMARY GRID SUBSTATION
Here, electric power is received by primary substation which reduces the voltage
level to 11KV for secondary transmission. The primary grid substation is generally of
outdoor type.
4.1.1.1.3 SECONDARY SUBSTATIONS
At a secondary substation, the voltage is further steeped down to 11KV. The
11KV lines runs along the important road of the city. The secondary substations are also
of outdoor type.
4.1.1.1.3 DISTRIBUTION SUBSTATION
These substations are located near the consumer’s localities and step down to
400V, 3-phase, 4-wire for supplying to the consumers. The voltage between any two
phases is 400V & between any phase and neutral it is 230V.
4.2 SUBSTATION CHARACTERISTICS:
4.2.1 Each circuit is protected by its own circuit breaker and hence plant outage does
not necessarily result in loss of supply.
4.2.2 A fault on the feeder or transformer circuit breaker causes loss of the transformer
and feeder circuit, one of which may be restored after isolating the faulty circuit
breaker.
16. 4.2.3 A fault on the bus section circuit breaker causes complete shutdown of the
substation. All circuits may be restored after isolating the faulty circuit breaker.
4.2.4 Maintenance of a feeder or transformer circuit breaker involves loss of the circuit.
4.2.5 Introduction of bypass isolators between bus bar and circuit isolator allows circuit
breaker maintenance facilities without loss of that circuit.
4.3 STEPS IN DESIGNING SUBSTATION:
The First Step in designing a Substation is to design an Earthing and Bonding System.
4.3.1 Earthing and Bonding:
The function of an earthing and bonding system is to provide an earthing system
connection to which transformer neutrals or earthing impedances may be connected in order to
pass the maximum fault current. The earthing system also ensures that no thermal or mechanical
damage occurs on the equipment within the substation, thereby resulting in safety to operation
and maintenance personnel. The earthing system also guarantees equipotent bonding such that
there are no dangerous potential gradients developed in the substation.
In designing the substation, three voltage have to be considered these are:
4.3.1.1 Touch Voltage:
This is the difference in potential between the surface potential and the potential at
earthed equipment whilst a man is standing and touching the earthed structure.
4.3.1.2 Step Voltage:
This is the potential difference developed when a man bridges a distance of 1m with his
feet while not touching any other earthed equipment.
4.3.1.3 Mesh Voltage:
This is the maximum touch voltage that is developed in the mesh of the earthing grid.
17. 4.3.2 Substation Earthing Calculation Methodology
Calculations for earth impedances, touch and step potentials are based on site
measurements of ground resistivity and system fault levels. A grid layout with particular
conductors is then analyzed to determine the effective substation earthing resistance, from which
the earthing voltage is calculated.
In practice, it is normal to take the highest fault level for substation earth grid calculation
purposes. Additionally, it is necessary to ensure a sufficient margin such that expansion of the
system is catered for.
To determine the earth resistivity, probe tests are carried out on the site. These tests are
best performed in dry weather such that conservative resistivity readings are obtained.
4.3.3 Earthing Materials
4.3.3.4 Conductors :
Bare copper conductor is usually used for the substation earthing grid. The copper bars
themselves usually have a cross-sectional area of 95 square millimeters, and they are laid at a
shallow depth of 0.25-0.5m, in 3-7m squares. In addition to the buried potential earth grid, a
separate above ground earthing ring is usually provided, to which all metallic substation plant is
bonded.
4.3.3.4 Connections:
Connections to the grid and other earthing joints should not be soldered because the heat
generated during fault conditions could cause a soldered joint to fail. Joints are usually bolted.
4.3.3.5 Earthing Rods:
18. The earthing grid must be supplemented by earthing rods to assist in the dissipation of earth fault
currents and further reduce the overall substation earthing resistance. These rods are usually
made of solid copper, or copper clad steel.
4.3.4 Switchyard Fence Earthing:
The switchyard fence earthing practices are possible and are used by different
utilities. These are:
4.3.4.1 Extend the substation earth grid 0.5m-1.5m beyond the fence perimeter. The fence
is then bonded to the grid at regular intervals.
4.3.4.2 Place the fence beyond the perimeter of the switchyard earthing grid and bond the
fence to its own earthing rod system. This earthing rod system is not coupled to the
main substation earthing grid.
4.4 CONDUCTORS USED IN SUBSTATION DESIGN:
An ideal conductor should fulfills the following requirements:
4.4.1 Should be capable of carrying the specified load currents and short time currents.
4.4.2 Should be able to withstand forces on it due to its situation. These forces comprise self
weight, and weight of other conductors and equipment, short circuit forces and
atmospheric forces such as wind and ice loading.
4.4.3 Should be corona free at rated voltage.
4.4.4 Should have the minimum number of joints.
4.4.5 Should need the minimum number of supporting insulators.
4.4.6 Should be economical.
The most suitable material for the conductor system is copper or aluminums. Steel may
be used but has limitations of poor conductivity and high susceptibility to corrosion.
In an effort to make the conductor ideal, three different types have been utilized, and
these include: Flat surfaced Conductors, Stranded Conductors, and Tubular Conductors
19. 4.5 Overhead Line Terminations
Two methods are used to terminate overhead lines at a substation.
4.5.1 Tensioning conductors to substation structures or buildings
4.5.2 Tensioning conductors to ground winches.
The choice is influenced by the height of towers and the proximity to the substation. The
following clearances should be observed:
VOLTAGE LEVEL MINIMUM GROUND CLEARANCE
less than 11kV 6.1m
11kV - 20kV 6.4m
20kV - 30kV 6.7m
greater than 30kV 7.0m
Table 1 Clearance in accordance with voltage value
20. 5. CHRONOLOGICAL TRAINING DIARY
( based on study & observation at different Departments and
sections)
5.1 POWER LINE CARRIER COMMUNICATION
Introduction:
Figure 5.1: PLCC (POWER LINE CARRIER COMMUNICATION)
Reliable & fast communication is necessary for safe efficient & economical power
supply. To reduce the power failure in extent & time, to maintain the interconnected grid system
in optimum working condition; to coordinate the operation of various generating unit
communication network is indispensable for state electricity board.
In state electricity boards, the generating & distribution stations are generally located at a
far distance from cities. Where P & T communication provided through long overhead lines in
neither reliable nor quick.
As we have available very reliable physical paths viz. the power lines, which
interconnected, hence power line carrier communication is found to be most economical and
reliable for electricity boards.
21. 5.1.1 APPLICATIONS:
The PLCC can be used for the following facilities:
5.1.1.1 Telephony
5.1.1.2 Teleprotection
5.1.1.3 Remote control or indication
5.1.1.4 Telemetry
5.1.1.5 Teleprinting
5.2 PRINCIPLE OF PLCC:
The principle of PLCC is the simple one:
All type of information is modulated on carried wave at frequency 50Hz to 500 KHz. The
modulated HF carrier fed into the power line conductor at the sending end and filtered out again
at the respective stations. Long earlier system double side band amplitude modulation was more
common but the present amplitude modulated system.
Since high voltage power lines are designed to carry large quantities of energy on the
high voltage and the communication system at low voltage, they cannot be directly connected to
high voltage lines. Suitably designed coupling equipments have therefore to be employed which
will permit the injection of high frequency carrier signal without undue loss and with absolute
protection of communication equipments or operating personal from high voltage hazard.
Therefore, the coupling equipment essentially comprises the following:
5.2.1 Wave trap or line trap:
Wave trap is connected in series with power line between the point of connection of
coupling capacitor and S/S. Wave trap offers negligible impedance to HF carrier. Wave trap
stands electromechanically and thermally for short circuit current in the event of fault on the line.
On the basis of blocking frequency bank, the wave trap can be following type:
5.2.1.1 ALL WAVE
5.2.1.2 SINGAL FREQUENCY
5.2.1.3 DOUBLE FREQUENCY
5.2.1.4 BROAD BAND
22. 5.2.2 Coupling capacitor:
The modulated carrier is let into power line through coupling capacitor specially designed
to with stand line voltage under all weather condition. The upper end of the coupling capacitor is
connected directly to the line and the lower end is connected to the ground through a carrier
frequency chock coil or drain coil. Thus coupling capacitor forms the link between the PLCC
equipment and power line. The coupling capacitor used in UPSEB is 2200pf capacitance.
The coupling capacitor are designed for outdoor use and hence to withstand normal
atmospheric phenomenon such as temperature & humidity changes, rain, snow, anticipated wind
load, nominal wire tension etc. at full rated voltage. In some case capacitive voltage transformers
(CVT) used as a source of line voltage for metering and protection as also used coupling
capacitor for PLCC.
5.2.3 Protective Device of Coarse Voltage Arrester:
This is connected across the primary of the coupling filter i.e. one end is connected to the
bottom of the coupling capacitor and other end is earthed. This is provided to protect the
coupling filter against line surges. An air gap is provided, where voltage of the order of 1.8 to
2KV as observed across due to lighting etc. on line.
5.2.4 Coupling of Filter:
The coupling filter is inserted between the low voltage terminal of the coupling capacitor
and the carrier frequency connection of the carrier terminal. Some time an earth switch is also
provided with this unit. This unit mainly performs two functions; firstly it isolates the connection
of equipment from the power line. Secondly it serves to match characteristic impedance of the
power line to that of the H.F. cable to connection equipments.
5.2.5 H.F. Cable:
H.F. cable normally used to connect the coupling filter to another coupling terminal. The
cable is insulated to withstand the test voltage of 4KV. The impedance of this H.F. cable is so as
to match with the output of the PLCC terminal and secondary impedance of coupling filter.
23. 5.2.5.1 TYPES OF COUPLING:
The following three types of coupling are being used in UPSEB depending on the
requirement:
5.2.5.1.1 Phase to ground coupling
5.2.5.1.2 Phase to phase coupling
5.2.5.1.3 Internal coupling
5.2.5.2 COUPLING LOSSES:
5.2.5.2.1 Composite loss
5.2.5.2.2 Tapping loss
5.2.5.2.3 H.F. cable loss
5.2.5.2.4 Additional loss
24. 6. BUSBARS
Figure 6.1 Typical representation of bus bars
When numbers of generators or feeders operating at the same voltage have to be directly
connected electrically, bus bar is used as the common electrical component. Bus bars are made
up of copper rods operate at constant voltage. The following are the important bus bars
arrangements used at substations:
6.1 Single bus bar system
6.2 Single bus bar system with section alisation.
6.3 Duplicate bus bar system
In large stations it is important that break downs and maintenance should interfere as little
as possible with continuity of supply to achieve this, duplicate bus bar system is used. Such a
system consists of two bus bars, a main bus bar and a spare bus bar with the help of bus coupler,
which consist of the circuit breaker and isolator.
In substations, it is often desired to disconnect a part of the system for general maintenance and
repairs. An isolating switch or isolator accomplishes this. Isolator operates under no load
condition. It does not have any specified current breaking capacity or current making capacity. In
25. some cases isolators are used to breaking charging currents or transmission lines.
While opening a circuit, the circuit breaker is opened first then isolator while closing a
circuit the isolator is closed first, then circuit breakers. Isolators are necessary on supply side of
circuit breakers, in order to ensure isolation of the circuit breaker from live parts for the purpose
of maintenance.
A transfer isolator is used to transfer main supply from main bus to transfer bus by using
bus coupler (combination of a circuit breaker with two isolators), if repairing or maintenance of
any section is required.
26. 7. INSULATORS
The insulator serves two purposes. They support the conductors (bus bar) and confine the
current to the conductors. The most common used material for the manufacture of insulator is
porcelain. There are several types of insulators (e.g. pin type, suspension type, post insulator etc.)
and their use in substation will depend upon the service requirement. For example, post insulator
is used for bus bars. A post insulator consists of a porcelain body, cast iron cap and flanged cast
iron base. The hole in the cap is threaded so that bus bars can be directly bolted to the cap.
Figure 7.1 Insulators used in substations
With the advantage of power system, the lines and other equipment operate at very high
voltage and carry high current.
The arrangements of switching along with switches cannot serve the desired function of
switchgear in such high capacity circuits. This necessitates employing a more dependable means
of control such as is obtain by the use of the circuit breakers. A circuit breaker can make or break
a circuit either manually or automatically under all condition as no load, full load and short
circuit condition.
A circuit breaker essentially consists of fixed and moving contacts. These contacts can be
opened manually or by remote control whenever desired. When a fault occurs on any part of the
system, the trip coils of breaker get energized and the moving contacts are pulled apart by some
27. mechanism, thus opening the circuit.
When contacts of a circuit breaker are separated, an arc is struck; the current is thus able
to continue. The production of arcs are not only delays the current interruption, but is also
generates the heat. Therefore, the main problem is to distinguish the arc within the shortest
possible time so that it may not reach a dangerous value.
The general way of classification is on the basis of the medium used for arc extinction.
Figure 7.2 Circuit breaker arrangements
7.1. Circuit breakers
They can be classified into:
7.1.1 Oil circuit breaker
7.1.2 Air-blast circuit breaker
7.1.3 Sulphar hexafluoride circuit breaker (SF6)
7.1.4 Vacuum circuit breakers
Note: SF6 and Vacuum circuit breaker are being used in 33KV distribution substation.
28. 7.2 Oil Circuit Breaker
Figure 7.3 Oil circuit breaker
A high-voltage circuit breaker in which the arc is drawn in oil to dissipate the heat and
extinguish the arc; the intense heat of the arc decomposes the oil, generating a gas whose high
pressure produces a flow of fresh fluid through the arc that furnishes the necessary insulation to
prevent a restrike of the arc.
The arc is then extinguished, both because of its elongation upon parting of contacts and
because of intensive cooling by the gases and oil vapor.
7.3 Air blast circuit breaker
Fast operations, suitability for repeated operation, auto reclosure, unit type multi break
constructions, simple assembly, modest maintenance are some of the main features of air blast
circuit breakers. A compressors plant necessary to maintain high air pressure in the air receiver.
The air blast circuit breakers are especially suitable for railways and arc furnaces, where the
breaker operates repeatedly. Air blast circuit breakers is used for interconnected lines and
29. important lines where rapid operation is desired.
Figure 7.4 Air blast circuit breaker
High pressure air at a pressure between 20 to 30 kg/ cm2 stored in the air reservoir. Air is
taken from the compressed air system. Three hollow insulator columns are mounted on the
reservoir with valves at their basis. The double arc extinguished chambers are mounted on the
top of the hollow insulator chambers. The current carrying parts connect the three arc extinction
chambers to each other in series and the pole to the neighboring equipment. Since there exists a
very high voltage between the conductor and the air reservoir, the entire arc extinction chambers
assembly is mounted on insulators.
7.4 SF6 CIRCUIT BREAKER:
Figure 7.5 SF6 Circuit breaker
30. In such circuit breaker, sulphar hexafluoride (SF6) gas is used as the arc quenching
medium. The SF6 is an electronegative gas and has a strong tendency to absorb free electrons.
The SF6 circuit breaker have been found to a very effective for high power and high voltage
service. SF6 circuit breakers have been developed for voltage 115 KV to 230 KV, power rating
10 MVA.
It consists of fixed and moving contacts. It has chamber, contains SF6 gas. When the
contacts are opened, the mechanism permits a high pressure SF6 gas from reservoir to flow
towards the arc interruption chamber. The moving contact permits the SF6 gas to let through
these holes.
7.5 Vacuum Circuit Breaker
Figure 7.6 Vacuum circuit breaker
Vacuum circuit breakers are circuit breakers which are used to protect medium and high
voltage circuits from dangerous electrical situations. Like other types of circuit breakers, vacuum
circuit breakers literally break the circuit so that energy cannot continue flowing through it,
thereby preventing fires, power surges, and other problems which may emerge. These devices
have been utilized since the 1920s, and several companies have introduced refinements to make
them even safer and more effective.
31. 7.2.1 Rating of 132 KV SF6 circuit breaker:
7.2.1.1 Breaking current: 50A
7.2.1.2 Making capacity: 80KA
7.2.1.3 Total break time < 60msec
7.2.1.4 Rated short circuit breaking current:
7.2.1.4.1 Symmetrical: 31.5 KA
7.2.1.4.2 Asymmetrical: 36.86 KA
7.2.1.5 Rated duration of short circuit current: 3sec
7.2.1.6 Rated nominal current: 1250 A
7.2.1.7 Rated voltage: 145 KV
7.2.1.8 Rated SF6 gas pressure: 6 KG
32. 8. METERING AND INDICATION EQUIPMENT
8.1 RELAY:
Figure 8.1 Relay
In a power system it is inevitable that immediately or later some failure does occur
somewhere in the system. When a failure occurs on any part of the system, it must be quickly
detected and disconnected from the system. Rapid disconnection of faulted apparatus limits the
amount of damage to it and prevents the effects of fault from spreading into the system. For high
voltage circuits relays are employed to serve the desired function of automatic protective gear.
The relays detect the fault and supply the information to the circuit breaker.
The electrical quantities which may change under fault condition are voltage, frequency,
current, phase angle. When a short circuit occurs at any point on the transmission line the current
flowing in the line increases to the enormous value. This result in a heavy current flow through
the relay coil, causing the relay to operate by closing its contacts. This in turn closes the trip
circuit of the breaker making the circuit breaker open and isolating the faulty section from the
rest of the system. In this way, the relay ensures the safety of the circuit equipment from the
damage and normal working of the healthy portion of the system. Basically relay work on the
following two main operating principles:
8.1.1 Electromagnetic attraction relay
8.1.2 Electromagnetic induction relay
33. 8.2 Relays used in control panel of the substation;
8.1.3 DIFFERENTIAL RELAY:
Figure 8.2 Differential Relay
A differential relay is one that operates when vector difference of the two or more
electrical quantities exceeds a predetermined value. If this differential quantity is equal or greater
than the pickup value, the relay will operate and open the circuit breaker to isolate the faulty
section.
8.1.4 OVER CURRENT RELAY:
Figure 8.3 Overcurrent Relay
This type of relay works when current in the circuit exceeds the predetermined value. The
actuating source is the current in the circuit supplied to the relay from a current transformer.
These relay are used on A.C. circuit only and can operate for fault flow in the either direction.
This relay operates when phase to phase fault occurs.
34. 8.1.5 DIRECTIONAL RELAY:
Figure8.4 Directional Relay
This relay operates during earth faults. If one phase touch the earth due to any fault. A
directional power relay is so designed that it obtains its operating torque by the interaction of
magnetic field derived from both voltage and current source of the circuit it protects. The
direction of torque depends upon the current relative to voltage.
8.1.6 TRIPPING RELAY:
Figure 8.5 Tripping Relay
This type of relay is in the conjunction with main relay. When main relay sense any fault in
the system, it immediately operates the trip relay to disconnect the faulty section from the section
35. 8.1.7 AUXILIARY RELAY:
Figure 8.6 Auxiliary Relay
An auxiliary relay is used to indicate the fault by glowing bulb alert the employee.
36. 9. MISCELLANOUS EQUIPMENT
9.1 CAPACITOR BANK:
Figure 9.1 Capacitor bank
The load on the power system is varying being high during morning and evening which
increases the magnetization current. This result in the decreased power factor. The low power
factor is mainly due to the fact most of the power loads are inductive and therefore take lagging
currents. The low power factor is highly undesirable as it causes increases in current, resulting in
additional losses. So in order to ensure most favorable conditions for a supply system from
engineering and economical stand point it is important to have power factor as close to unity as
possible. In order to improve the power factor come device taking leading power should be
connected in parallel with the load. One of the such device can be capacitor bank. The capacitor
draws a leading current and partly or completely neutralize the lagging reactive component of
load current.
Capacitor bank accomplishes following operations:
9.1.1 Supply reactive power
9.1.2 Increases terminal voltage
9.1.3 Improve power factor
37. 9.2 FUSE:
Figure 9.2 Substation Fuse
A fuse is a short piece of wire or thin strip which melts when excessive current through it
for sufficient time. It is inserted in series with the circuit under normal operating conditions; the
fuse element is at a nature below its melting point. Therefore it carries the normal load current
overheating. It is worthwhile to note that a fuse performs both detection and interruption
functions.
9.3 BUS COUPLER:
Figure 9.3 bus coupler
The bus coupler consists of circuit breaker and isolator. Each generator and feeder may
be connected to either main bus bar or spar bus bar with the help of bus coupler. Repairing,
maintenance and testing of feeder circuit or other section can be done by putting them on spar
bus bar, thus keeping the main bus bar undisturbed.
38. 10. PROTECTION OF SUBSTATION:
10.1 Transformer protection:
Transformers are totally enclosed static devices and generally oil immersed. Therefore
chances of fault occurring on them are very easy rare, however the consequences of even a rare
fault may be very serious unless the transformer is quickly disconnected from the system. This
provides adequate automatic protection for transformers against possible faults.
10.2 Conservator and Breather:
When the oil expands or contacts by the change in the temperature, the oil level goes
either up or down in main tank. A conservator is used to maintain the oil level up to
predetermined value in the transformer main tank by placing it above the level of the top of the
tank.
Breather is connected to conservator tank for the purpose of extracting moisture as it
spoils the insulating properties of the oil. During the contraction and expansion of oil air is
drawn in or out through breather silica gel crystals impregnated with cobalt chloride. Silica gel is
checked regularly and dried and replaced when necessary.
10.3 Marshalling box:
It has two meter which indicate the temperature of the oil and winding of main tank. If
temperature of oil or winding exceeds than specified value, relay operates to sound an alarm. If
there is further increase in temperature then relay completes the trip circuit to open the circuit
breaker controlling the transformer.
10.4 Transformer cooling:
When the transformer is in operation heat is generated due to iron losses the removal of
heat is called cooling.
39. There are several types of cooling methods, they are as follows:
10.4.1 Air natural cooling:
In a dry type of self cooled transformers, the natural circulation of surrounding air is used
for its cooling. This type of cooling is satisfactory for low voltage small transformers.
10.4.2 Air blast cooling:
It is similar to that of dry type self cooled transformers with to addition that continuous
blast of filtered cool air is forced through the core and winding for better cooling. A fan produces
the blast.
10.4.3 Oil natural cooling:
Medium and large rating have their winding and core immersed in oil, which act both as
a cooling medium and an insulating medium. The heat produce in the cores and winding is
passed to the oil becomes lighter and rises to the top and place is taken by cool oil from the
bottom of the cooling tank.
10.4.4 Oil blast cooling:
In this type of cooling, forced air is directed over cooling elements of transformers
immersed in oil.
10.4.5 Forced oil and forced air flow (OFB) cooling:
Oil is circulated from the top of the transformers tank to a cooling tank to a cooling plant.
Oil is then returned to the bottom of the tank.
10.4.6 Forced oil and water (OWF) cooling:
In this type of cooling oil flow with water cooling of the oil in external water heat
exchanger takes place. The water is circulated in cooling tubes in the heat exchanger.
40. 11. CONCLUSION
Now from this report we can conclude that electricity plays an important role in our life.
We are made aware of how the transmission of electricity is done. We too came to know about
the various parts of the Substation system.
The Uttar Pradesh Cooperation Limited has got radio communication in microwave
range in order to transmit and receive data with various Substations in Uttar Pradesh to get
reliable transmission and distribution of electricity.