This document provides an overview of current transformers (CTs), including their purpose, construction, testing, and applications. It discusses how CTs transform high currents to measurable levels for metering and protection devices. CTs must be tested during commissioning to verify accuracy and ensure proper operation of connected equipment. Tests include excitation curve measurement, ratio accuracy testing, and insulation testing. Proper handling and connection of CTs is important to avoid issues during operation.
IRJET- A Mitigation of Voltage Fluctuation on Small Scale IndustryIRJET Journal
This document discusses voltage fluctuations that can damage equipment in small industries and presents a solution using a voltage stabilizer. It begins with an introduction to power quality issues like voltage sags, swells, and interruptions that are caused by problems in the power system. It then describes the components and working of a small model of a voltage stabilizer that uses a phase controller technique to regulate the voltage and maintain a constant level as the load changes, in order to protect equipment from damage caused by fluctuations. Diagrams of the circuit are provided and calculations for determining the firing angle of thyristors in the stabilizer are shown.
MV Switchgear provides centralized control and protection of medium-voltage power equipment and circuits in industrial, commercial, and utility installations involving generators, motors, feeder circuits, and transmission and distribution lines.
IRJET- Numerical Differential Protection of 220/132KV, 250 MVA Auto Transform...IRJET Journal
This document discusses the numerical differential protection of a 250MVA, 220/132kV power transformer using a Siemens 7UT612 numerical differential relay. It first describes challenges in setting electromechanical differential relays, including balancing current magnitudes and phase angles between the HV and LV sides due to different CT ratios and the transformer's vector group. It then summarizes key capabilities of the 7UT612 relay like adjustable pickup and slope settings, through fault stability via saturation detection, and harmonic restraint for inrush currents using second and fifth harmonic blocking. Setting calculations are shown for a sample electromechanical relay installation.
IRJET - Design and Simulation of DSTATCOM using Fuzzy Logic ControllerIRJET Journal
This document discusses the design and simulation of a DSTATCOM (distributed static compensator) using a fuzzy logic controller. A DSTATCOM is a shunt-connected voltage source converter that can generate or absorb reactive power to improve power quality issues like voltage sags and swells. The document first provides background on power quality issues and the factors driving increased focus on power quality. It then describes the basic components and operating principle of a DSTATCOM for reactive power compensation and power factor correction. Finally, it discusses controlling strategies for DSTATCOM, including using a fuzzy logic supervisor to vary the gains of a PI controller and improve transient performance of the DC link voltage during load changes.
IRJET- Power Quality Improvement using Dynamic Voltage Restorer (DVR)IRJET Journal
1) The document discusses power quality issues such as voltage sags and proposes using a Dynamic Voltage Restorer (DVR) to improve power quality.
2) A DVR injects voltage into the distribution system through an injection transformer to compensate for voltage sags and restore the load voltage to its normal level.
3) The document presents a MATLAB simulation of a DVR connected to a distribution system with two loads - a sensitive load and a normal load. When a fault is created, the DVR injects voltage and is able to maintain the sensitive load voltage at its normal level, protecting it from the voltage sag.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
IRJET- A Mitigation of Voltage Fluctuation on Small Scale IndustryIRJET Journal
This document discusses voltage fluctuations that can damage equipment in small industries and presents a solution using a voltage stabilizer. It begins with an introduction to power quality issues like voltage sags, swells, and interruptions that are caused by problems in the power system. It then describes the components and working of a small model of a voltage stabilizer that uses a phase controller technique to regulate the voltage and maintain a constant level as the load changes, in order to protect equipment from damage caused by fluctuations. Diagrams of the circuit are provided and calculations for determining the firing angle of thyristors in the stabilizer are shown.
MV Switchgear provides centralized control and protection of medium-voltage power equipment and circuits in industrial, commercial, and utility installations involving generators, motors, feeder circuits, and transmission and distribution lines.
IRJET- Numerical Differential Protection of 220/132KV, 250 MVA Auto Transform...IRJET Journal
This document discusses the numerical differential protection of a 250MVA, 220/132kV power transformer using a Siemens 7UT612 numerical differential relay. It first describes challenges in setting electromechanical differential relays, including balancing current magnitudes and phase angles between the HV and LV sides due to different CT ratios and the transformer's vector group. It then summarizes key capabilities of the 7UT612 relay like adjustable pickup and slope settings, through fault stability via saturation detection, and harmonic restraint for inrush currents using second and fifth harmonic blocking. Setting calculations are shown for a sample electromechanical relay installation.
IRJET - Design and Simulation of DSTATCOM using Fuzzy Logic ControllerIRJET Journal
This document discusses the design and simulation of a DSTATCOM (distributed static compensator) using a fuzzy logic controller. A DSTATCOM is a shunt-connected voltage source converter that can generate or absorb reactive power to improve power quality issues like voltage sags and swells. The document first provides background on power quality issues and the factors driving increased focus on power quality. It then describes the basic components and operating principle of a DSTATCOM for reactive power compensation and power factor correction. Finally, it discusses controlling strategies for DSTATCOM, including using a fuzzy logic supervisor to vary the gains of a PI controller and improve transient performance of the DC link voltage during load changes.
IRJET- Power Quality Improvement using Dynamic Voltage Restorer (DVR)IRJET Journal
1) The document discusses power quality issues such as voltage sags and proposes using a Dynamic Voltage Restorer (DVR) to improve power quality.
2) A DVR injects voltage into the distribution system through an injection transformer to compensate for voltage sags and restore the load voltage to its normal level.
3) The document presents a MATLAB simulation of a DVR connected to a distribution system with two loads - a sensitive load and a normal load. When a fault is created, the DVR injects voltage and is able to maintain the sensitive load voltage at its normal level, protecting it from the voltage sag.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
IRJET- PV System Connected High Step-Up Boost DC-DC Converter based Voltag...IRJET Journal
1. The document presents a photovoltaic (PV) system interfaced with a high step-up DC-DC converter to support the DC link of a dynamic voltage restorer (DVR) and alleviate voltage sags and swells in a low voltage power distribution system.
2. The high step-up DC-DC boost converter uses a coupled inductor design to achieve high voltage gain from the low output of the PV array while maintaining low voltage stress on the power switches. This reduces the size and power rating needed for the series injection transformer.
3. Simulation results show the effectiveness of the proposed PV-supported DVR in mitigating voltage sags and swells in a low voltage single-
Neil Kirby: VSC HVDC Transmission and Emerging Technologies in DC GridsEnergyTech2015
The document discusses emerging HVDC transmission and grid technologies presented by Neil Kirby at EnergyTech2015. It summarizes HVDC converter types, control methods for HVDC grids using slack bus and droop control, protection challenges for DC grids, and future converter technologies like modular multi-level converters that enable DC circuit breakers. It presents diagrams and examples of various converter configurations including full bridge and alternate arm designs that could help realize more versatile and controllable DC grids.
IRJET - Digital Differential Protection of Power Transformer using MATLABIRJET Journal
1) The document discusses digital differential protection of power transformers using MATLAB. Differential protection relies on the principle that the input power to a transformer under normal conditions equals the output power.
2) It describes how current transformers are used to compare primary and secondary currents and send any difference to a relay to trip for internal faults. The MATLAB model simulates different types of faults like line-to-ground and line-to-line-to-ground.
3) Differential protection provides fast, selective protection for expensive equipment like transformers. It is not affected by external faults but cannot operate during those conditions. The technology is made more accurate and flexible using microcontrollers.
Product: Power Factor & Harmonics: StacoSine: TechnicalStaco Energy
This document discusses power factor, harmonics, and power quality issues. It defines power factor as the ratio of real power to apparent power, and explains how low power factor means electrical power is not being fully utilized. Common sources of harmonics and symptoms caused by harmonics are outlined. The document also provides an overview of power factor correction capacitors and considerations for their application, as well as basics of harmonics and potential economic impacts.
IRJET- Mollification Parameter Control by Dynamic Voltage Restorer (DVR)IRJET Journal
The document discusses using a Dynamic Voltage Restorer (DVR) to mitigate voltage sags. A DVR is a series-connected device that uses power electronics to quickly restore load voltage to pre-fault levels during voltage sags. It works by injecting the missing voltage back into the system. A DVR consists of an inverter, filter, booster transformer, DC storage such as capacitors, and control system. It monitors the voltage and injects only the amount needed to compensate for the sag using pulse width modulation of the inverter. This allows it to restore the voltage quickly and improve power quality for sensitive loads affected by voltage sags.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
EV Charging Infrastructure: Littelfuse Solutions to Enhance Safety, Efficienc...Littelfuse
Discover the wide range of Littelfuse EV charging infrastructure solutions in our automotive electronics portfolio, including silicon carbide (SiC) devices.
The document provides a report on training undergone by Er.R.S.Rajprasad at the Vallur Thermal Power Project from 29-06-2015 to 12-07-2015. It summarizes the key activities during the training, including testing of switchgear relays, battery capacitance testing, transformer testing, stability testing of motor relays, and studying the plant profile. The training provided valuable practical experience in linking electrical engineering theory to practice in a power generation facility. The internship was concluded to be an excellent learning experience.
IRJET- A Novel High Speed Power Efficient Double Tail Comparator in 180nm...IRJET Journal
This document presents a novel double tail comparator design that aims to improve speed and power efficiency over existing comparator designs. It first discusses conventional comparator designs and their limitations at lower voltages. It then introduces a new 16 transistor double tail comparator configuration that includes control transistors, intermediate transistors, and NMOS switches to reduce power and delay. Simulation results show the transient response and estimate the power and delay of the new design, demonstrating performance improvements over conventional designs. The design was laid out using the Cadence Virtuoso tool.
IRJET- Design and Analysis of Single Ended Primary Inductance Converter (SEPI...IRJET Journal
This document describes the design and analysis of a single-ended primary inductance converter (SEPIC) for battery-powered devices using MATLAB simulation. A SEPIC converter can both boost and buck voltages from the battery, providing a steady output voltage as the battery discharges. The document discusses SEPIC converter topology, duty cycle considerations, inductor selection, and simulates a SEPIC converter in MATLAB. The simulation shows the SEPIC converter providing a regulated 15.32V output from a 20V input with 76.6% efficiency.
IRJET- An Inclusive Review on Various Multilevel Converter Topologies for a G...IRJET Journal
This document reviews various multilevel inverter topologies that can be used for grid-connected photovoltaic systems. It discusses four main topologies: diode-clamped, flying capacitor, cascaded, and Z-source inverters. For each topology, the document outlines their construction, advantages, and disadvantages when used in renewable energy power systems. It finds that cascaded inverters require fewer components than other topologies but many separate DC sources, while diode-clamped and flying capacitor inverters can share a single DC source but have more complex voltage balancing requirements. The review aims to help selection of the appropriate multilevel inverter topology based on specific system needs and tradeoffs between component counts and control complexity
Electrical & MEP Design - Study material.pdfsureshrajan38
The document provides information on mechanical, electrical, and plumbing (MEP) systems for buildings. It discusses the roles of mechanical, electrical, and public health engineering in building design and construction. It also outlines some common challenges in MEP coordination and design, including limited building space, construction schedules, and lack of skilled workers. Additionally, it provides cost breakdowns for typical MEP systems, lists various electrical components and their specifications, and discusses standards and best practices for electrical design, installation, and testing.
Overcoming 25 year life reliability challenges in solar electronicsGreg Caswell
This document discusses reliability challenges for solar electronics, particularly inverters, that must last for 25 years. It notes that central inverters and their components like IGBTs are leading causes of failures. Micro-inverters and power optimizers are presented as alternatives that improve reliability by distributing the electronics over many individual modules rather than having a single point of failure. The document discusses various failure modes for electronic components like solder joints and methods to improve reliability through design choices, testing, and modeling lifetime under stress conditions.
The document discusses Aggregate Technical & Commercial (AT&C) losses in power distribution. It provides definitions and formulas for calculating AT&C losses and their components. The main reasons for technical losses are overloading of lines/equipment, lack of maintenance and upgrades, and low power factor. The main reasons for commercial losses are theft, defective meters, billing/collection inefficiencies, and tampering of metering systems.
IRJET - Closed Loop Control of Non Isolated Positive Output Buck Boost D...IRJET Journal
This document describes the closed loop control of a non-isolated positive output buck-boost DC-DC converter using a genetic algorithm based PI controller. The converter achieves high voltage gain without using a transformer. State space modeling and derivation of the transfer function are performed to design the controller. Open loop simulations are conducted without and with disturbances to validate the converter's effectiveness. A genetic algorithm is then used to tune the PI controller parameters to minimize the integrated time absolute error for closed loop control of the converter.
IRJET- Designing of Single Ended Primary Inductance Converter for Solar P...IRJET Journal
This document describes the design and modeling of a Single Ended Primary Inductance Converter (SEPIC) DC-DC converter for photovoltaic applications. A SEPIC converter is proposed to boost or buck the variable voltage from a solar panel to meet load requirements. An incremental conductance maximum power point tracking (MPPT) algorithm is used for better efficiency. The converter output is fed to a sinusoidal pulse width modulation inverter to convert DC to AC for AC loads. The SEPIC converter design and component selection process is explained. The system is modeled and tested using MATLAB/Simulink software and shown to reduce ripple current and provide a non-inverted output voltage compared to other converter types.
Review on Automatic Power Factor Improvement of Induction MotorIRJET Journal
This document provides a review of techniques for automatic power factor improvement of induction motors. It begins with an abstract discussing the purpose of designing new techniques for power factor improvement in 3-phase and single-phase induction motors. The document then reviews the various components involved in an automatic power factor improvement system using a microcontroller, including the power supply, zero crossing detectors, microcontroller, electromagnetic relays, LCD display, capacitor bank, and software details. It concludes that power factor correction techniques can make power systems more stable and efficient while reducing costs when using a microcontroller.
artificial intelligence and data science contents.pptxGauravCar
What is artificial intelligence? Artificial intelligence is the ability of a computer or computer-controlled robot to perform tasks that are commonly associated with the intellectual processes characteristic of humans, such as the ability to reason.
› ...
Artificial intelligence (AI) | Definitio
IRJET- PV System Connected High Step-Up Boost DC-DC Converter based Voltag...IRJET Journal
1. The document presents a photovoltaic (PV) system interfaced with a high step-up DC-DC converter to support the DC link of a dynamic voltage restorer (DVR) and alleviate voltage sags and swells in a low voltage power distribution system.
2. The high step-up DC-DC boost converter uses a coupled inductor design to achieve high voltage gain from the low output of the PV array while maintaining low voltage stress on the power switches. This reduces the size and power rating needed for the series injection transformer.
3. Simulation results show the effectiveness of the proposed PV-supported DVR in mitigating voltage sags and swells in a low voltage single-
Neil Kirby: VSC HVDC Transmission and Emerging Technologies in DC GridsEnergyTech2015
The document discusses emerging HVDC transmission and grid technologies presented by Neil Kirby at EnergyTech2015. It summarizes HVDC converter types, control methods for HVDC grids using slack bus and droop control, protection challenges for DC grids, and future converter technologies like modular multi-level converters that enable DC circuit breakers. It presents diagrams and examples of various converter configurations including full bridge and alternate arm designs that could help realize more versatile and controllable DC grids.
IRJET - Digital Differential Protection of Power Transformer using MATLABIRJET Journal
1) The document discusses digital differential protection of power transformers using MATLAB. Differential protection relies on the principle that the input power to a transformer under normal conditions equals the output power.
2) It describes how current transformers are used to compare primary and secondary currents and send any difference to a relay to trip for internal faults. The MATLAB model simulates different types of faults like line-to-ground and line-to-line-to-ground.
3) Differential protection provides fast, selective protection for expensive equipment like transformers. It is not affected by external faults but cannot operate during those conditions. The technology is made more accurate and flexible using microcontrollers.
Product: Power Factor & Harmonics: StacoSine: TechnicalStaco Energy
This document discusses power factor, harmonics, and power quality issues. It defines power factor as the ratio of real power to apparent power, and explains how low power factor means electrical power is not being fully utilized. Common sources of harmonics and symptoms caused by harmonics are outlined. The document also provides an overview of power factor correction capacitors and considerations for their application, as well as basics of harmonics and potential economic impacts.
IRJET- Mollification Parameter Control by Dynamic Voltage Restorer (DVR)IRJET Journal
The document discusses using a Dynamic Voltage Restorer (DVR) to mitigate voltage sags. A DVR is a series-connected device that uses power electronics to quickly restore load voltage to pre-fault levels during voltage sags. It works by injecting the missing voltage back into the system. A DVR consists of an inverter, filter, booster transformer, DC storage such as capacitors, and control system. It monitors the voltage and injects only the amount needed to compensate for the sag using pulse width modulation of the inverter. This allows it to restore the voltage quickly and improve power quality for sensitive loads affected by voltage sags.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
EV Charging Infrastructure: Littelfuse Solutions to Enhance Safety, Efficienc...Littelfuse
Discover the wide range of Littelfuse EV charging infrastructure solutions in our automotive electronics portfolio, including silicon carbide (SiC) devices.
The document provides a report on training undergone by Er.R.S.Rajprasad at the Vallur Thermal Power Project from 29-06-2015 to 12-07-2015. It summarizes the key activities during the training, including testing of switchgear relays, battery capacitance testing, transformer testing, stability testing of motor relays, and studying the plant profile. The training provided valuable practical experience in linking electrical engineering theory to practice in a power generation facility. The internship was concluded to be an excellent learning experience.
IRJET- A Novel High Speed Power Efficient Double Tail Comparator in 180nm...IRJET Journal
This document presents a novel double tail comparator design that aims to improve speed and power efficiency over existing comparator designs. It first discusses conventional comparator designs and their limitations at lower voltages. It then introduces a new 16 transistor double tail comparator configuration that includes control transistors, intermediate transistors, and NMOS switches to reduce power and delay. Simulation results show the transient response and estimate the power and delay of the new design, demonstrating performance improvements over conventional designs. The design was laid out using the Cadence Virtuoso tool.
IRJET- Design and Analysis of Single Ended Primary Inductance Converter (SEPI...IRJET Journal
This document describes the design and analysis of a single-ended primary inductance converter (SEPIC) for battery-powered devices using MATLAB simulation. A SEPIC converter can both boost and buck voltages from the battery, providing a steady output voltage as the battery discharges. The document discusses SEPIC converter topology, duty cycle considerations, inductor selection, and simulates a SEPIC converter in MATLAB. The simulation shows the SEPIC converter providing a regulated 15.32V output from a 20V input with 76.6% efficiency.
IRJET- An Inclusive Review on Various Multilevel Converter Topologies for a G...IRJET Journal
This document reviews various multilevel inverter topologies that can be used for grid-connected photovoltaic systems. It discusses four main topologies: diode-clamped, flying capacitor, cascaded, and Z-source inverters. For each topology, the document outlines their construction, advantages, and disadvantages when used in renewable energy power systems. It finds that cascaded inverters require fewer components than other topologies but many separate DC sources, while diode-clamped and flying capacitor inverters can share a single DC source but have more complex voltage balancing requirements. The review aims to help selection of the appropriate multilevel inverter topology based on specific system needs and tradeoffs between component counts and control complexity
Electrical & MEP Design - Study material.pdfsureshrajan38
The document provides information on mechanical, electrical, and plumbing (MEP) systems for buildings. It discusses the roles of mechanical, electrical, and public health engineering in building design and construction. It also outlines some common challenges in MEP coordination and design, including limited building space, construction schedules, and lack of skilled workers. Additionally, it provides cost breakdowns for typical MEP systems, lists various electrical components and their specifications, and discusses standards and best practices for electrical design, installation, and testing.
Overcoming 25 year life reliability challenges in solar electronicsGreg Caswell
This document discusses reliability challenges for solar electronics, particularly inverters, that must last for 25 years. It notes that central inverters and their components like IGBTs are leading causes of failures. Micro-inverters and power optimizers are presented as alternatives that improve reliability by distributing the electronics over many individual modules rather than having a single point of failure. The document discusses various failure modes for electronic components like solder joints and methods to improve reliability through design choices, testing, and modeling lifetime under stress conditions.
The document discusses Aggregate Technical & Commercial (AT&C) losses in power distribution. It provides definitions and formulas for calculating AT&C losses and their components. The main reasons for technical losses are overloading of lines/equipment, lack of maintenance and upgrades, and low power factor. The main reasons for commercial losses are theft, defective meters, billing/collection inefficiencies, and tampering of metering systems.
IRJET - Closed Loop Control of Non Isolated Positive Output Buck Boost D...IRJET Journal
This document describes the closed loop control of a non-isolated positive output buck-boost DC-DC converter using a genetic algorithm based PI controller. The converter achieves high voltage gain without using a transformer. State space modeling and derivation of the transfer function are performed to design the controller. Open loop simulations are conducted without and with disturbances to validate the converter's effectiveness. A genetic algorithm is then used to tune the PI controller parameters to minimize the integrated time absolute error for closed loop control of the converter.
IRJET- Designing of Single Ended Primary Inductance Converter for Solar P...IRJET Journal
This document describes the design and modeling of a Single Ended Primary Inductance Converter (SEPIC) DC-DC converter for photovoltaic applications. A SEPIC converter is proposed to boost or buck the variable voltage from a solar panel to meet load requirements. An incremental conductance maximum power point tracking (MPPT) algorithm is used for better efficiency. The converter output is fed to a sinusoidal pulse width modulation inverter to convert DC to AC for AC loads. The SEPIC converter design and component selection process is explained. The system is modeled and tested using MATLAB/Simulink software and shown to reduce ripple current and provide a non-inverted output voltage compared to other converter types.
Review on Automatic Power Factor Improvement of Induction MotorIRJET Journal
This document provides a review of techniques for automatic power factor improvement of induction motors. It begins with an abstract discussing the purpose of designing new techniques for power factor improvement in 3-phase and single-phase induction motors. The document then reviews the various components involved in an automatic power factor improvement system using a microcontroller, including the power supply, zero crossing detectors, microcontroller, electromagnetic relays, LCD display, capacitor bank, and software details. It concludes that power factor correction techniques can make power systems more stable and efficient while reducing costs when using a microcontroller.
artificial intelligence and data science contents.pptxGauravCar
What is artificial intelligence? Artificial intelligence is the ability of a computer or computer-controlled robot to perform tasks that are commonly associated with the intellectual processes characteristic of humans, such as the ability to reason.
› ...
Artificial intelligence (AI) | Definitio
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
Rainfall intensity duration frequency curve statistical analysis and modeling...bijceesjournal
Using data from 41 years in Patna’ India’ the study’s goal is to analyze the trends of how often it rains on a weekly, seasonal, and annual basis (1981−2020). First, utilizing the intensity-duration-frequency (IDF) curve and the relationship by statistically analyzing rainfall’ the historical rainfall data set for Patna’ India’ during a 41 year period (1981−2020), was evaluated for its quality. Changes in the hydrologic cycle as a result of increased greenhouse gas emissions are expected to induce variations in the intensity, length, and frequency of precipitation events. One strategy to lessen vulnerability is to quantify probable changes and adapt to them. Techniques such as log-normal, normal, and Gumbel are used (EV-I). Distributions were created with durations of 1, 2, 3, 6, and 24 h and return times of 2, 5, 10, 25, and 100 years. There were also mathematical correlations discovered between rainfall and recurrence interval.
Findings: Based on findings, the Gumbel approach produced the highest intensity values, whereas the other approaches produced values that were close to each other. The data indicates that 461.9 mm of rain fell during the monsoon season’s 301st week. However, it was found that the 29th week had the greatest average rainfall, 92.6 mm. With 952.6 mm on average, the monsoon season saw the highest rainfall. Calculations revealed that the yearly rainfall averaged 1171.1 mm. Using Weibull’s method, the study was subsequently expanded to examine rainfall distribution at different recurrence intervals of 2, 5, 10, and 25 years. Rainfall and recurrence interval mathematical correlations were also developed. Further regression analysis revealed that short wave irrigation, wind direction, wind speed, pressure, relative humidity, and temperature all had a substantial influence on rainfall.
Originality and value: The results of the rainfall IDF curves can provide useful information to policymakers in making appropriate decisions in managing and minimizing floods in the study area.
Design and optimization of ion propulsion dronebjmsejournal
Electric propulsion technology is widely used in many kinds of vehicles in recent years, and aircrafts are no exception. Technically, UAVs are electrically propelled but tend to produce a significant amount of noise and vibrations. Ion propulsion technology for drones is a potential solution to this problem. Ion propulsion technology is proven to be feasible in the earth’s atmosphere. The study presented in this article shows the design of EHD thrusters and power supply for ion propulsion drones along with performance optimization of high-voltage power supply for endurance in earth’s atmosphere.
3. Current
Transformer
Main Tasks of Current Transformers
▪ Transform currents from high levels to measureable levels
▪ Insulate the secondary circuits from the high voltage network
▪ Standardize meters and relays
June , 2020 | Slide 03
4. Current
Transformer
Convert Primary Power Signals to Manageable Values for
▪ Indicating Meters
▪ Revenue Metering
▪ Protective Relay Systems
▪ Power Generation
▪ Plant Monitoring Systems
▪ Fault Recorders
▪ SCADA
▪ Overall Electric Grid Monitoring (Local Dispatch & ISO Level)
▪ Building (Energy) Management Systems
▪ Load Control
June , 2020 | Slide 04
11. Current
Transformer
Live Tank vs Dead Tank CT
▪ The core with secondary winding is housed in the
top tank which is live ( At high voltage)
▪ The core with secondary winding is housed in the
bottom tank which is earthed (Dead)
▪ Core and Secondary winding - isolated ▪ Only primary winding is isolated
▪ Insulation is robust and reliable ▪ Insulation is not robust
▪ Primary winding is of shortest length possible
which offers high strength against the short time
dynamic force
▪ Primary winding has to pass through the porcelain
insulator and the larger length of primary
conductor produces maxm mechanical force
during short time dynamic force
▪ Minimum heat generation, maximum dissipation ▪ Maximum heat generation, minimum dissipation
▪ Compact and economical ▪ Bulky and costly
June , 2020 | Slide 11
14. Current
Transformer
Definition as per IEC 60044-1
▪ Accuracy Class : a designation assigned to a current transformer the error of which remain within
specified limits under prescribed conditions of use
▪ Burden : the impedance of secondary circuit in ohms and power-factor. Usually expressed in VA
▪ Instrument Security factor (FS): the ratio of rated instrument limit primary current to the rated
primary current
▪ Accuracy Limit Factor (ALF) : the ratio of the rated accuracy limit primary current to the rated
primary current
▪ Rated Knee-Point e.m.f : the minimum sinusoidal e.m.f at rated power frequency when applied to
the secondary terminals of the transformer, all others terminals being open circuited , which when
increased by 10% causes the r.m.s exciting current to increase by no more than 50%. The actual
knee point emf will be equal or greater rated knee point emf.
June , 2020 | Slide 14
17. Current
Transformer
CTs for Protection and Metering Applications
▪ A distinction has to be made between a Metering and Protection Class CT
▪ The designs of the magnetic cores are different
▪ This ensures that they perform according to the needs of the particular device
connected
June , 2020 | Slide 17
18. Current
Transformer
Properties of Metering Core
▪ High Accuracy in a smaller range ( 5-120% of rated current / 1-120% for class S)
▪ Low Burden
▪ Low Over Current Factor (FS) (At FS, Core saturated and Accuracy isn’t guaranteed)
▪ Leads to lower Saturation Voltage ( Protects Metering Devices from overloading)
June , 2020 | Slide 18
22. Current
Transformer
Properties of Protection Core
▪ Designed to transform a distortion-free signal even well into the overcurrent
range
▪ Current range 100% of rated current to ALF x rated current
▪ Relays are required to perform in fault current type situations
▪ Low accuracy requirements
▪ High saturation voltage
▪ More core material is needed
June , 2020 | Slide 22
23. Current
Transformer
Standard Accuracy Classes for Protection
▪ 5P and 10P
▪ PX (User defined CT performance)
• Turn Ratio error should not exceed ± 0.25%
• Rated Knee point emf (𝐸𝑘)
• Maximum exciting current (𝐼𝑒) at rated (𝐸𝑘)
• Maximum Resistance (𝑅𝑐𝑡) at 75°C
June , 2020 | Slide 23
26. Current
Transformer
Testing CTs
When ?
▪ Initial Commissioning
▪ Investigation
▪ Scheduled
Why ?
▪ Verify Factory Tests
▪ Ordered/Delivered Correctly
▪ Ensure no Damages
June , 2020 | Slide 26
27. Current
Transformer
Test Methods
▪ Primary Injection
▪ Secondary Injection – Fixed Frequency
▪ Secondary Injection – Variable Frequency
Test Requirements
▪ Determination of Knee/Saturation Point
▪ Insulation
▪ Polarity
▪ Winding Resistance
▪ Primary/Secondary Ratio ( %Ratio Error )
▪ Burden Check
▪ Tan-Delta
▪ Documentation / Visual Check
June , 2020 | Slide 27
28. Current
Transformer
Why so many Tests
▪ Ensure proper Relay Operations
▪ Certify Billing Accuracy
▪ Reduce Possibility of Failure when Energized
▪ Manufacturing Defects Do Happen
▪ Installation Error Do Happens
June , 2020 | Slide 28
29. Current
Transformer
Before Testing Starts
▪ Ask Concerned Personnel to isolate CTs ( Electrically & Mechanically )
▪ DON’T Operate Yourself
▪ Ensure Isolation Yourself - Physically
▪ Use Caution Tape to avoid enthusiastic people from entering premises
▪ Ground One-End (P1 / P2 ) to avoid Induced Voltage
▪ Take notes if removal of secondary connection requires
▪ Ensure Proper Grounding of Testing Kits
▪ Collect FAT / Previous Test Reports
▪ Revert to Original Connection after Tests end ( Ensure Yourself )
June , 2020 | Slide 29
33. Current
Transformer
Testing Turn Ratio Error%
Current Error% =
𝐾𝑛𝐼𝑠−𝐼𝑝 ×100
𝐼𝑝
Kn = Rated Transformation Ratio
Is = Actual / Measured Secondary Current
Ip = Actual / Measured Primary Current
June , 2020 | Slide 33
34. Current
Transformer
Measuring Secondary Winding Resistance
▪ Usually done with AVO Meter but recommended way is to do with Test Kit / CT Analyzer
▪ Convert Resistance Value at 75°C and compare with Reference / Rated Value
▪ It’s the simplest test for diagnosing CT Secondary . It should be the 1st test to perform on CT if Core
Demagnetization option is available, otherwise, perform it at last.
▪ As DC current leads to Residual Magnetism, it may jeopardize other tests Accuracy
June , 2020 | Slide 34
35. Current
Transformer
How CTs Secondary are Connected
▪ Always Connected in SERIES
▪ Don’t Connect Burden Beyond its Rating
▪ Connect Cores as per Designation of
Devices
▪ Don’t Interchange CT Cores
June , 2020 | Slide 35
36. Current
Transformer
CTs Performance at Through-Fault
▪ CTs are designed to sustain a through-fault condition without being saturated
▪ To avoid saturation CT should develop adequate voltage at secondary
▪ Extra burden should not be imposed beyond its rating
▪ For Differential Protection, PX class CTs are recommended to be used as they are
calculated to provide sufficient voltage during a through-fault
For Protection Purposes, CTs are NEVER Expected to be Saturated
June , 2020 | Slide 36
37. Current
Transformer
Dos and Don’ts at Commissioning
▪ Do Primary Injection and check Continuity throughout the secondary circuit
▪ Measure Secondary Current as per transformation ratio at each junction point with Clamp Meter
▪ Ensure proper Core Allocation & Polarity
▪ Avoid Double-Grounding as it leads to Wrong Measurement
▪ Tighten CT secondary with Utmost care. Double Check !
▪ NEVER Leave CTs Secondary OPENED
▪ Once Primary Injection is done successfully, DON’T Touch CT secondary or Change Connections
▪ If Changes are made, Perform Primary Injection AGAIN
June , 2020 | Slide 37