1) Transformer polarity refers to the relative direction of induced voltages between the high voltage and low voltage windings. It depends on how the coils are wound and how the leads are connected.
2) The dot convention is used to indicate phase relationship between the primary and secondary windings. Matching dots mean in-phase voltages, while non-matching dots mean 180 degree out of phase voltages.
3) A polarity test can determine if a transformer has additive or subtractive polarity by measuring the sum or difference of voltages when connecting corresponding terminals.
This document discusses the parallel operation of transformers with equal and unequal voltage ratios. It notes that for parallel operation, transformers must have equal voltage ratios, impedances, polarities, phase sequences, ratings, and frequencies. It explains that with unequal ratios, a circulating current will occur under no load conditions due to the difference in induced voltages. The document also states that with equal ratios and in-phase voltages, the primaries and secondaries can be connected in parallel without circulating current under no load.
The document discusses Flexible AC Transmission Systems (FACTS) devices for enhancing power transmission. It describes several types of FACTS controllers including series controllers like the Thyristor Controlled Series Capacitor (TCSC) and shunt controllers like the Static Synchronous Compensator (STATCOM). TCSC uses thyristors to vary the capacitive reactance in series with the transmission line, enabling increased power transfer. STATCOM maintains bus voltage by injecting reactive current and has advantages over SVC like faster response and modularity.
The document summarizes the key components and functions of a 33/11kV substation in Indiranagar, Lucknow, Uttar Pradesh, India. It contains 10 sections that describe the introduction, transformer, isolator, circuit breaker, relay, lightning arrester, current/potential transformers, capacitor bank, and conclusion. The substation receives power from two 33kV transmission lines and steps it down through 3 parallel 10MVA transformers for distribution through 11 feeders to various areas in Indiranagar. It contains critical equipment like switchgear, isolators, circuit breakers, relays, and instrument transformers to safely transmit and distribute power. Capacitor banks are also included to improve the power
Este documento trata sobre las pérdidas de potencia en transformadores y su eficiencia. Explica que en un transformador hay pérdidas debido a las resistencias en los bobinados y al hierro, así como a la dispersión del flujo magnético. Detalla los tipos de pérdidas, incluyendo las pérdidas por corrientes de Foucault y histéresis en el hierro, y las pérdidas por efecto Joule en los bobinados. También describe brevemente el funcionamiento básico de un transformador e introduce conceptos como el
Power System Dynamics and Control Presentation on Unit 3Chaitra Panat
In this presentation we see the concept of power system stability with their classification, concept of power system stabilizer and types then basic concept of control signals in Power system stabilizers, its structure and tuning, field implementation and operating Experiences, Advantages, disadvantages, applications, future scope and conclusion
This document discusses the parallel operation of transformers with equal and unequal voltage ratios. It notes that for parallel operation, transformers must have equal voltage ratios, impedances, polarities, phase sequences, ratings, and frequencies. It explains that with unequal ratios, a circulating current will occur under no load conditions due to the difference in induced voltages. The document also states that with equal ratios and in-phase voltages, the primaries and secondaries can be connected in parallel without circulating current under no load.
The document discusses Flexible AC Transmission Systems (FACTS) devices for enhancing power transmission. It describes several types of FACTS controllers including series controllers like the Thyristor Controlled Series Capacitor (TCSC) and shunt controllers like the Static Synchronous Compensator (STATCOM). TCSC uses thyristors to vary the capacitive reactance in series with the transmission line, enabling increased power transfer. STATCOM maintains bus voltage by injecting reactive current and has advantages over SVC like faster response and modularity.
The document summarizes the key components and functions of a 33/11kV substation in Indiranagar, Lucknow, Uttar Pradesh, India. It contains 10 sections that describe the introduction, transformer, isolator, circuit breaker, relay, lightning arrester, current/potential transformers, capacitor bank, and conclusion. The substation receives power from two 33kV transmission lines and steps it down through 3 parallel 10MVA transformers for distribution through 11 feeders to various areas in Indiranagar. It contains critical equipment like switchgear, isolators, circuit breakers, relays, and instrument transformers to safely transmit and distribute power. Capacitor banks are also included to improve the power
Este documento trata sobre las pérdidas de potencia en transformadores y su eficiencia. Explica que en un transformador hay pérdidas debido a las resistencias en los bobinados y al hierro, así como a la dispersión del flujo magnético. Detalla los tipos de pérdidas, incluyendo las pérdidas por corrientes de Foucault y histéresis en el hierro, y las pérdidas por efecto Joule en los bobinados. También describe brevemente el funcionamiento básico de un transformador e introduce conceptos como el
Power System Dynamics and Control Presentation on Unit 3Chaitra Panat
In this presentation we see the concept of power system stability with their classification, concept of power system stabilizer and types then basic concept of control signals in Power system stabilizers, its structure and tuning, field implementation and operating Experiences, Advantages, disadvantages, applications, future scope and conclusion
The document discusses power flow in transmission lines, explaining that the flow of active and reactive power can be controlled by varying factors like the voltage magnitudes at each end, the phase angle difference between the voltages, and the reactance of the transmission line. It provides diagrams to illustrate how active power flow is affected by these parameters and how controlling devices can regulate power flow through injection of voltages in series with the transmission line.
This document discusses power factor correction. It defines power factor as the ratio of actual power to apparent power. Inductive loads cause low power factors by creating a phase difference between voltage and current. Low power factors increase losses and costs. Power factor can be corrected by installing capacitors to supply reactive power and improve the phase relationship. Proper power factor correction increases system capacity, reduces losses, saves costs through efficiency improvements and utility incentives, and improves voltage stability.
Synchronous generators operate on the principle of electromagnetic induction. They have a stationary armature winding and a rotating field winding supplied by a direct current source. It is advantageous to have the field winding on the rotor and armature winding on the stator because it allows for easier insulation of the high voltage winding and direct connection to the load. The frequency of the induced voltage depends on the number of rotor poles and its rotational speed. Armature reaction is the effect of the armature magnetic field on the main rotor field, distorting or strengthening it depending on the load power factor.
This document provides an overview of sag-tension calculations for overhead power lines. It discusses key parameters like maximum sag, tension, and span length. Sag determines electrical clearances while tension impacts structure design. The document covers the catenary curve model and factors like conductor weight and elongation. It also summarizes considerations for non-homogeneous conductors like ACSR. Numerical examples show how temperature changes impact sag and tension. Experimental data and computer models are needed due to the nonlinear behavior of composite conductors.
- A per-unit system expresses system quantities as fractions of a defined base unit quantity, allowing analysis of large interconnected power systems with various voltage levels and equipment capacities.
- To define a per-unit system requires specifying base values for voltage, current, apparent power, and impedance. Quantities can then be expressed as ratios of their actual to base values.
- Per-unit representation simplifies analysis by removing different voltage levels and reducing the system to simple impedances. It also allows easy comparison of equipment impedances irrespective of actual size.
This presentation is brief introduction to the transient disturbances(how they occur and reason behind that) and its classification(Oscillatory and Impulsive).
- The document discusses different types of armature windings for DC and AC machines, including lap, wave, simplex, duplex, mush, and double layer windings.
- It describes the characteristics of each winding type such as the connections between coils and how they are arranged in the slots. Key terms related to pitch, spacing, and phase relationships are also defined.
- The final section covers conditions for designing double layer windings for AC machines, distinguishing between integral and fractional slot types.
- Transmission line faults are mainly transient faults caused by lightning or persistent faults from downed lines.
- Distance protection relies on measuring the impedance between the relay and the fault to determine the fault location and operate selectively.
- Distance relays divide the line into zones and use different impedance thresholds and time delays for each zone to coordinate with protection on adjacent line sections.
Parallel Operation of a Single Phase TransformerRidwanul Hoque
Three transformers can be connected in parallel to increase capacity and reliability. This allows one transformer to be taken offline for maintenance without interrupting power, and maintains supply if one transformer fails. For proper parallel operation, transformers must have the same: primary voltage and frequency; polarity connection; voltage rating and ratio; percentage impedance; and resistance to reactance ratio. Unequal values can cause circulating currents that reduce efficiency and overload transformers.
1. The document discusses synchronous machines which are used as AC generators and motors. It describes the construction of synchronous machines including salient pole and round rotor types.
2. An equation for the induced EMF in a synchronous generator is derived. Key factors affecting the EMF like pitch factor and distribution factor are explained.
3. The operation of synchronous generators is discussed when connected to loads. The effect of load power factor on the phase relationship between induced EMF and current is summarized.
This document describes the design and performance study of a two-quadrant chopper drive. It begins with an introduction to choppers and their classification. It then discusses the different types of choppers - first quadrant, second quadrant, two-quadrant types A and B. It outlines the operations carried out by choppers and the components used in the model. Observations from the test circuit are presented along with graphs. Advantages include the ability for forward motoring and braking. Applications include electric vehicles and traction motor control. The conclusion is that regenerative braking is possible using a two-quadrant chopper.
Dokumen tersebut membahas tentang desain dan pembuatan isolator listrik. Secara umum membahas tentang isolator porselen, isolator kaca, dan komponen-komponen penting seperti logam dan semen yang digunakan. Juga membahas perkembangan berbagai jenis isolator dan faktor yang mempengaruhi kinerja isolator.
Learn about Instrument transformers, current transformers, and potential transformers in this presentation given by Georgia Power at the Caribbean Meter School. 01/29/2019
Perhitungan Listrik 1 Fase dan Perbaikan Faktor DayaYusrizal Azmi
Dokumen tersebut membahas tentang listrik satu fase dan perbaikan faktor daya. Ia menjelaskan konsep dasar listrik satu fase, besaran-besaran seperti daya aktif, reaktif dan semu, serta manfaat pemasangan kapasitor pengkoreksi faktor daya untuk meningkatkan efisiensi sistem listrik dan mengurangi beban biaya konsumen dan produsen listrik.
This document discusses the parallel operation of transformers. It explains that transformers can be connected in parallel to supply excess load or when a single transformer is not large enough. For proper parallel operation, the transformers must have the same voltage ratio, per unit impedance, polarity, and phase sequence. Additionally, the short-circuit impedances should be approximately equal to ensure proper load sharing.
This document discusses transformer design and design parameters. It covers topics such as transformer ratings, core design, insulation coordination, voltages, impedance, forces, losses, temperature limits, and cooling. Standards from organizations like IEEE, ANSI, and NEMA are also referenced. Transformer design involves selecting appropriate ratings and parameters to meet requirements while considering factors like performance, reliability, insulation, cooling, and costs.
The project focuses on the harmonic analysis of transformer during the switching transient period. Measuring fundamental and second harmonics of differential current, an algorithm based on the Discrete Fourier Transform and an amplitude estimator are used to simulate and list various harmonic components of current and flux. Generalized functions for describing the relationships between resultant flux and harmonic components are derived. This is important to find these relations for further use in detecting non-linearity and elimination of harmonic components.
This document discusses power angle curve calculation for a single machine connected to an infinite bus. It defines an infinite bus as one whose voltage and frequency remain constant even with load variations. The document then presents an equation to calculate the active and reactive power transferred from the generator to the system based on the generator voltage, infinite bus voltage, and load angle. It describes that maximum power transfer occurs at a load angle of 0 degrees and explains how the power angle curve is used to study power system stability by graphically representing the relationship between active power and load angle.
- Tesla proposed using transformers in power distribution systems to step up voltage for transmission and step down voltage for consumption, reducing power losses.
- A transformer consists of coils wrapped around a common core and converts AC voltage from one level to another at the same frequency through electromagnetic induction.
- Transformers allow impedance matching between generation/transmission systems and distribution/consumption systems through voltage transformation ratios.
A transformer is a device that changes alternating current (ac) electric power at one voltage level to ac power at another voltage level through magnetic induction. It consists of two or more coils wound around a core and linked by a magnetic field. An ideal transformer has no losses and the power input equals the power output. Real transformers have losses due to winding resistance, core losses, and leakage fluxes. The performance of real transformers can be modeled using an equivalent circuit with parameters determined from open-circuit and short-circuit tests. Transformer voltage regulation and efficiency are important performance metrics.
The document discusses power flow in transmission lines, explaining that the flow of active and reactive power can be controlled by varying factors like the voltage magnitudes at each end, the phase angle difference between the voltages, and the reactance of the transmission line. It provides diagrams to illustrate how active power flow is affected by these parameters and how controlling devices can regulate power flow through injection of voltages in series with the transmission line.
This document discusses power factor correction. It defines power factor as the ratio of actual power to apparent power. Inductive loads cause low power factors by creating a phase difference between voltage and current. Low power factors increase losses and costs. Power factor can be corrected by installing capacitors to supply reactive power and improve the phase relationship. Proper power factor correction increases system capacity, reduces losses, saves costs through efficiency improvements and utility incentives, and improves voltage stability.
Synchronous generators operate on the principle of electromagnetic induction. They have a stationary armature winding and a rotating field winding supplied by a direct current source. It is advantageous to have the field winding on the rotor and armature winding on the stator because it allows for easier insulation of the high voltage winding and direct connection to the load. The frequency of the induced voltage depends on the number of rotor poles and its rotational speed. Armature reaction is the effect of the armature magnetic field on the main rotor field, distorting or strengthening it depending on the load power factor.
This document provides an overview of sag-tension calculations for overhead power lines. It discusses key parameters like maximum sag, tension, and span length. Sag determines electrical clearances while tension impacts structure design. The document covers the catenary curve model and factors like conductor weight and elongation. It also summarizes considerations for non-homogeneous conductors like ACSR. Numerical examples show how temperature changes impact sag and tension. Experimental data and computer models are needed due to the nonlinear behavior of composite conductors.
- A per-unit system expresses system quantities as fractions of a defined base unit quantity, allowing analysis of large interconnected power systems with various voltage levels and equipment capacities.
- To define a per-unit system requires specifying base values for voltage, current, apparent power, and impedance. Quantities can then be expressed as ratios of their actual to base values.
- Per-unit representation simplifies analysis by removing different voltage levels and reducing the system to simple impedances. It also allows easy comparison of equipment impedances irrespective of actual size.
This presentation is brief introduction to the transient disturbances(how they occur and reason behind that) and its classification(Oscillatory and Impulsive).
- The document discusses different types of armature windings for DC and AC machines, including lap, wave, simplex, duplex, mush, and double layer windings.
- It describes the characteristics of each winding type such as the connections between coils and how they are arranged in the slots. Key terms related to pitch, spacing, and phase relationships are also defined.
- The final section covers conditions for designing double layer windings for AC machines, distinguishing between integral and fractional slot types.
- Transmission line faults are mainly transient faults caused by lightning or persistent faults from downed lines.
- Distance protection relies on measuring the impedance between the relay and the fault to determine the fault location and operate selectively.
- Distance relays divide the line into zones and use different impedance thresholds and time delays for each zone to coordinate with protection on adjacent line sections.
Parallel Operation of a Single Phase TransformerRidwanul Hoque
Three transformers can be connected in parallel to increase capacity and reliability. This allows one transformer to be taken offline for maintenance without interrupting power, and maintains supply if one transformer fails. For proper parallel operation, transformers must have the same: primary voltage and frequency; polarity connection; voltage rating and ratio; percentage impedance; and resistance to reactance ratio. Unequal values can cause circulating currents that reduce efficiency and overload transformers.
1. The document discusses synchronous machines which are used as AC generators and motors. It describes the construction of synchronous machines including salient pole and round rotor types.
2. An equation for the induced EMF in a synchronous generator is derived. Key factors affecting the EMF like pitch factor and distribution factor are explained.
3. The operation of synchronous generators is discussed when connected to loads. The effect of load power factor on the phase relationship between induced EMF and current is summarized.
This document describes the design and performance study of a two-quadrant chopper drive. It begins with an introduction to choppers and their classification. It then discusses the different types of choppers - first quadrant, second quadrant, two-quadrant types A and B. It outlines the operations carried out by choppers and the components used in the model. Observations from the test circuit are presented along with graphs. Advantages include the ability for forward motoring and braking. Applications include electric vehicles and traction motor control. The conclusion is that regenerative braking is possible using a two-quadrant chopper.
Dokumen tersebut membahas tentang desain dan pembuatan isolator listrik. Secara umum membahas tentang isolator porselen, isolator kaca, dan komponen-komponen penting seperti logam dan semen yang digunakan. Juga membahas perkembangan berbagai jenis isolator dan faktor yang mempengaruhi kinerja isolator.
Learn about Instrument transformers, current transformers, and potential transformers in this presentation given by Georgia Power at the Caribbean Meter School. 01/29/2019
Perhitungan Listrik 1 Fase dan Perbaikan Faktor DayaYusrizal Azmi
Dokumen tersebut membahas tentang listrik satu fase dan perbaikan faktor daya. Ia menjelaskan konsep dasar listrik satu fase, besaran-besaran seperti daya aktif, reaktif dan semu, serta manfaat pemasangan kapasitor pengkoreksi faktor daya untuk meningkatkan efisiensi sistem listrik dan mengurangi beban biaya konsumen dan produsen listrik.
This document discusses the parallel operation of transformers. It explains that transformers can be connected in parallel to supply excess load or when a single transformer is not large enough. For proper parallel operation, the transformers must have the same voltage ratio, per unit impedance, polarity, and phase sequence. Additionally, the short-circuit impedances should be approximately equal to ensure proper load sharing.
This document discusses transformer design and design parameters. It covers topics such as transformer ratings, core design, insulation coordination, voltages, impedance, forces, losses, temperature limits, and cooling. Standards from organizations like IEEE, ANSI, and NEMA are also referenced. Transformer design involves selecting appropriate ratings and parameters to meet requirements while considering factors like performance, reliability, insulation, cooling, and costs.
The project focuses on the harmonic analysis of transformer during the switching transient period. Measuring fundamental and second harmonics of differential current, an algorithm based on the Discrete Fourier Transform and an amplitude estimator are used to simulate and list various harmonic components of current and flux. Generalized functions for describing the relationships between resultant flux and harmonic components are derived. This is important to find these relations for further use in detecting non-linearity and elimination of harmonic components.
This document discusses power angle curve calculation for a single machine connected to an infinite bus. It defines an infinite bus as one whose voltage and frequency remain constant even with load variations. The document then presents an equation to calculate the active and reactive power transferred from the generator to the system based on the generator voltage, infinite bus voltage, and load angle. It describes that maximum power transfer occurs at a load angle of 0 degrees and explains how the power angle curve is used to study power system stability by graphically representing the relationship between active power and load angle.
- Tesla proposed using transformers in power distribution systems to step up voltage for transmission and step down voltage for consumption, reducing power losses.
- A transformer consists of coils wrapped around a common core and converts AC voltage from one level to another at the same frequency through electromagnetic induction.
- Transformers allow impedance matching between generation/transmission systems and distribution/consumption systems through voltage transformation ratios.
A transformer is a device that changes alternating current (ac) electric power at one voltage level to ac power at another voltage level through magnetic induction. It consists of two or more coils wound around a core and linked by a magnetic field. An ideal transformer has no losses and the power input equals the power output. Real transformers have losses due to winding resistance, core losses, and leakage fluxes. The performance of real transformers can be modeled using an equivalent circuit with parameters determined from open-circuit and short-circuit tests. Transformer voltage regulation and efficiency are important performance metrics.
1) The document discusses the history and operation of transformers, including their use in power distribution systems to step up voltage for transmission and step down voltage for distribution to loads.
2) A transformer consists of coils wrapped around a common core and works by electromagnetic induction to convert AC voltages from one level to another while maintaining the same frequency.
3) An ideal transformer is analyzed, and equations are provided showing how it transforms voltages and currents while maintaining power, reactive power, and power factor between windings. Impedance transformation is also discussed.
A transformer is a device that changes alternating current (ac) electric power at one voltage level to ac electric power at another voltage level through the action of a magnetic field. An ideal transformer is a lossless device that transfers power efficiently between its two windings. A real transformer is modeled using an equivalent circuit that accounts for power losses, including copper losses, eddy current losses, hysteresis losses, and leakage fluxes. The parameters of the equivalent circuit can be determined experimentally using open-circuit and short-circuit tests.
1. Tesla proposed using step-up and step-down transformers in power distribution systems to increase transmission voltage and decrease losses. This allowed efficient long-distance AC power transmission.
2. A transformer consists of coils wrapped around a common core and works based on electromagnetic induction. It converts one AC voltage to another by exploiting the mutual flux between its windings.
3. An ideal transformer does not change the phase relationship between voltages and currents on its two sides but only their magnitudes, allowing impedance transformation. Real transformers have some leakage flux and losses.
A transformer transfers electrical energy between two or more circuits through electromagnetic induction. It works on the principle of mutual induction between two or more windings due to a changing magnetic field. Transformers are used to increase or decrease alternating voltages in power applications. The primary winding is supplied with alternating current which produces a changing magnetic flux in the transformer core. This changing flux induces a changing voltage in the secondary winding due to electromagnetic induction based on Faraday's law of induction. Real transformers have losses such as core losses from hysteresis and eddy currents, as well as winding resistance losses. Transformers can be modeled using an equivalent circuit to represent these losses and other factors.
The document discusses transformers and their operation. It begins by introducing transformers and their basic components. There are two main types of construction: core type and shell type. An ideal transformer is then described as having no losses, infinite core permeability, and zero resistance windings. The document explains how an ideal transformer works based on Faraday's law of induction. It also discusses voltage and current ratios, impedance transformation, and power relationships for an ideal transformer. Real transformers are then discussed, including voltage ratios, magnetizing current, and equivalent circuits.
The document discusses transformers and their operation. It begins by introducing transformers and their basic components. There are two main types of construction: core type and shell type. An ideal transformer is then described as having no losses, infinite core permeability, and no leakage flux. The document explains how a real transformer works based on Faraday's law of induction and the separation of flux into mutual and leakage components. It derives the voltage and current ratios for an ideal transformer and discusses impedance transformation.
1. A transformer is a device that converts alternating current (AC) of one voltage to another voltage without changing the frequency. It consists of coils wrapped around a common core and uses electromagnetic induction.
2. Nikola Tesla proposed using transformers to increase voltage for efficient power transmission over long distances, then step it back down for safe distribution and use. This system replaced the inefficient direct current system developed by Edison.
3. Transformers allow efficient transmission of power by reducing current and thus transmission losses, while maintaining the same power level. They are essential components for modern power distribution systems.
The document discusses potentiometers and their use in measuring electrical quantities. It describes:
1) The construction and working of DC potentiometers including slide wire and Crompton types, and their applications in measuring resistance, calibrating voltmeters and ammeters.
2) The construction of AC potentiometers including in-phase and quadrature types, and their standardization process.
3) How potentiometers can be used to accurately measure small voltages and currents by balancing the unknown quantity against a known standard voltage.
Experimental verification of network theorems, ugc practical physics s_paulspaul15
This document describes an experiment to verify several network theorems including Thevenin's theorem, Norton's theorem, superposition theorem, and the maximum power transfer theorem. The experiment uses a Wheatstone bridge circuit with resistors R1-R4 and a voltage source. Measurements are taken at various load resistances RL and graphs are plotted to experimentally determine the Thevenin resistance Rth, Thevenin voltage Vth, Norton current In, and maximum power transfer. Direct measurements are also taken and compared to theoretical calculations to verify the network theorems.
Electricity and Electromagnetism (experimental study)Raboon Redar
You’ll understand the way to calculate and measure resistance in parallel and series circuits by knowing two of the three values of voltage, current, or resistance. In this experiment, there are 3 resistors, 1 power supply and wires you need for connecting resistors to each other, then to power supply. You can measure each resistor by an ohmmeter, voltages by voltmeter and currents by amperemeter (ammeter), while all of them can be measured by a multimeter. Use a multimeter for measuring resistance for better accuracy.
This document describes DC and AC potentiometers. It discusses the Vernier potentiometer which has two measurement ranges down to 10uV and 1uV. It also describes the Drysdale polar type AC potentiometer which uses a phase shifting transformer to measure both the magnitude and phase of an unknown voltage. Finally, it discusses the Gall Tinsley coordinate type AC potentiometer which uses two potentiometers to measure the in-phase and quadrature components of an unknown voltage.
An A.C. device used to change high voltage low current A.C. into low voltage high current A.C. and vice-versa without changing the frequency
In brief,
1. Transfers electric power from one circuit to another
2. It does so without a change of frequency
3. It accomplishes this by electromagnetic induction
4. Where the two electric circuits are in mutual inductive influence of each other.
This document provides information about EHV AC and DC transmission, specifically components of EHV DC systems and converter circuits. It discusses:
1) The main components of EHV DC systems include converter transformers, thyristor valves, bus bars, and series reactors. Converters use thyristor valves connected in a three-phase full-wave bridge circuit to convert AC to DC and vice versa.
2) Converters require reactive power, which is supplied by AC filters, shunt capacitors or synchronous condensers. Operation of converters generates harmonic voltages and currents that can cause equipment heating, interference, and other issues if not mitigated.
3) Harmonics are mitigated using AC and DC
This document provides an overview of transformers and their operation. It discusses:
- The history and development of transformers from the 1880s to present day
- The basic components and construction of transformers
- How an ideal transformer works based on Faraday's law of induction
- How voltages and currents are related in an ideal transformer based on turn ratios
- How real transformers approximate ideal transformer behavior
- Examples of analyzing circuits containing transformers by referring their sides
- The theory of operation for real single-phase transformers based on mutual and leakage fluxes
Power transformers work by mutual induction between two windings without any direct electrical connection. An alternating current applied to the primary winding produces an alternating magnetic flux that links with the secondary winding. This induces an alternating voltage in the secondary winding due to Faraday's law of induction. The primary winding is connected to the power source and the secondary winding supplies power to the load. The transformation ratio is determined by the number of turns in each winding and determines whether the transformer steps up or steps down the voltage. Transformer losses include copper losses in the windings and magnetic (iron) losses in the core.
The document discusses DC to AC conversion using inverters. It describes the basic concept and components of inverters including single-phase, full-bridge, and three-phase inverter topologies. It also covers modulation techniques such as pulse width modulation (PWM) and discusses how they affect the output waveform harmonics.
This document discusses short circuits, open circuits, and transformer tests. It explains that a short circuit allows current along an unintended path with little resistance, while an open circuit lacks a complete path for current flow. Transformer tests include open circuit and short circuit tests. The open circuit test determines core losses and shunt branch parameters, while the short circuit test determines copper losses and approximate circuit parameters. Instruments are connected and measurements recorded to evaluate losses and parameters from the tests.
This document discusses the design of a three-phase current source inverter. It describes the main components of the current source inverter including a chopper circuit, inverter switching arrangement, and control circuit. Shift registers are used to generate six pulse signals with 60 degree phase shifts that are fed to the thyristors to produce the three-phase output. The current source inverter provides advantages over voltage source inverters like short circuit protection and simpler control circuits.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
RHEOLOGY Physical pharmaceutics-II notes for B.pharm 4th sem students
Polaritas trafo
1. POLARITAS TRAFO
PENDAHULUAN
Fasor dan polaritas adalah dua alat penting dan berguna dalam proteksi sistem daya.
Keduanya membantu dalam pemahaman dan analisis dari hubungan, operasi, dan pengujian
relay-relay dan sistem. Selain itu, konsep-konsep ini penting dalam memahami kinerja sistem
daya selama kedua operasi normal dan abnormal. Dengan demikian, pengetahuan teoritis dan
praktis suara fasor dan polaritas adalah sumber daya mendasar dan berharga.
The polarity of a device with mutual inductance designates the relative
instantaneous current directions of such device's winding leads. Leads of primary and
secondary windings are said be of the same polarity when instantaneous current entering the
primary winding lead results in instantaneous current leaving the secondary winding lead as
though the two leads were a continuous circuit. In the case of two windings wound around the
same core in parallel, for example, the polarity will be the same on the same ends: A sudden
(instantaneous) current in the first coil will induce a voltage opposing the sudden increase
(Lenz's law) in the first and also in the second coil, because the inductive magnetic field
produced by the current in the first coil traverses the two coils in the same manner. The
second coil will therefore show an induced current opposite in direction to the inducing
current in the first coil. Both leads behave like a continuous circuit, one current entering into
the first lead and another current leaving the second lead.
THE IMPORTANCE OF POLARITY
An understanding of polarity is essential to correctly construct three phase
transformer banks and to properly parallel single or three phase transformers with existing
electrical systems. A knowledge of polarity is also required to connect potential and current
transformers to power metering devices and protective relays. The basic theory of additive
and subtractive polarity is the underlying principle used in step voltage regulators where the
series winding of an autotransformer is connected to either buck or boost the applied line
voltage. Transformer polarity depends on which direction coils are wound around the core
(clockwise or counterclockwise) and how the leads are brought out, see in figure 1.
2. Figure 1. Direction coils are wound around the core
TRANSFORMER POLARITY
Transformer polarity refers to the relative direction of the induced voltages between
the high voltage terminals and the low voltage terminals. Two methods are commonly used to
denote which terminals present the same relative polarity. A dot may be used, or an
alphanumeric designation. Alphanumeric designations are typically in the form H1 for
primaries, and for secondaries, X1, (and Y1, Z1, if more windings present). These markings may
be found on transformer cases beside terminals, winding leads, nameplates, schematic and wiring
diagrams. During the AC half cycle when the applied voltage (or current in the case of a
current transformer) is from H1 to H2 the secondary induced voltage direction will be from
X1 to X2. In practice, Polarity refers to the way the leads are brought out of the transformer.
More often, transformer polarity is shown simply by the American National Standards Institute
(ANSI) designations of the winding leads as H1, H2 and X1, X2. By ANSI standards, if you face the
low-voltage side of a single-phase transformer (the side marked X1, X2), the H1 connection will
always be on your far left. If the terminal marked X1 is also on your left, it is subtractive polarity. If
the X1 terminal is on your right, it is additive polarity see in figure 2.
Additive polarity is common for small distribution transformers. Large transformers, such as
GSUs at Reclamation powerplants, are generally subtractive polarity. It is also helpful to think of
polarity marks in terms of current direction. At any instant when the current direction is into a
polarity marked terminal of the primary winding, the current direction is out of the terminal with the
3. same polarity mark in the secondary winding. It is the same as if there were a continuous circuit
across the two windings.
Figure 2. Alphanumeric Designation by ANSI present the same relative polarity
POLARITY TEST
Polarity test in situations where the secondary bushing identification is not available or when
a transformer has been rewound, it may be necessary to determine the transformer polarity by
test. The following procedure can be used. Polarity is a convenient way of starting how leads
are brought out. If you want to test for polarity, connect the transformer as shown in figure 3.
A transformer is said to have additive polarity if, when adjacent high and low-voltage terminals are
connected and a voltmeter placed across the other high- and low-voltage terminals, the voltmeter
reads the sum (additive) of the high- and low-voltage windings. It is subtractive polarity if the
voltmeter reads the difference (subtractive) between the voltages of the two windings. If this test is
conducted, use the lowest AC voltage available to reduce potential hazards. An adjustable ac
voltage source, such as a variac, is recommended to keep the test voltage low.
4. Figure 3. Wiring of Polarity Test
Simply polarity test :
Additve polarity : V3 = V1+V2
Substractive polarity : V3 = V1-V2
Example below :
If the transformer is actually rated 480 -120 volts, the transformer ratio is
4:1 (480/120 = 4). 480 volt as primary voltage, 120 volt as secondary voltage. Applying a test
voltage of 120 volts to the primary will result in a secondary voltage of 30 volts (120 / 4 =
30). If transformer is subtractive polarity, the voltmeter (V3) will read 90 volts (120-30 = 90).
If the voltmeter (V3) reads 150 volts, the transformer is additive polarity (120 + 30 = 150).
THE DOT IN TRANSFORMER
Since transformers are essentially AC devices, we need to be aware of the phase
relationships between the primary and secondary circuits. Using our SPICE example from
before, we can plot the waveshapes (Figure 4 below) for the primary and secondary circuits
and see the phase relations for ourselves :
spice transient analysis file for use with nutmeg: transformer v1 1 0 sin(0
15 60 0 0) rbogus1 1 2 1e-12 v2 5 0 dc 250 l1 2 0 10000 l2 3 5 100 k l1 l2
0.999 vi1 3 4 ac 0 rload 4 5 1k .tran 0.5m 17m .end nutmeg commands:
setplot tran1 plot v(2) v(3,5)
5. Figure 4. Plot The Waveshapes
It would appear that both voltage and current for the two transformer windings are in-
phase with each other, at least for our resistive load. This is simple enough, but it would be
nice to know which way we should connect a transformer in order to ensure the proper phase
relationships be kept. After all, a transformer is nothing more than a set of magnetically-
linked inductors, and inductors don’t usually come with polarity markings of any kind. If we
were to look at an unmarked transformer, we would have no way of knowing which way to
hook it up to a circuit to get in-phase (or 180o
out-of-phase) voltage and current.
Figure 5. Ambiguous
As a practical matter, the polarity of a transformer can be ambiguous like figure 5
above. Since this is a practical concern, transformer manufacturers have come up with a sort
of polarity marking standard to denote phase relationships. It is called the dot convention,
and is nothing more than a dot placed next to each corresponding leg of a transformer
winding, show in figure 6 below.
6. Figure 6. The Dot Convention
A pair of dots indicates like polarity, show in figure 6. Typically, the transformer
will come with some kind of schematic diagram labeling the wire leads for primary and
secondary windings. On the diagram will be a pair of dots similar to what is seen above.
Sometimes dots will be omitted, but when “H” and “X” labels are used to label transformer
winding wires, the subscript numbers are supposed to represent winding polarity. The “1”
wires (H1 and X1) represent where the polarity-marking dots would normally be placed.
The similar placement of these dots next to the top ends of the primary and secondary
windings tells us that whatever instantaneous voltage polarity seen across the primary
winding will be the same as that across the secondary winding. In other words, the phase shift
from primary to secondary will be zero degrees.
On the other hand, if the dots on each winding of the transformer do not match
up, the phase shift will be 180o
between primary and secondary, like this. See in figure 7.
Figure 7. The dots are not match
Out of phase: primary red to dot, secondary black to dot. Of course, the dot convention only
tells you which end of each winding is which, relative to the other winding(s). If you want to
reverse the phase relationship yourself, all you have to do is swap the winding connections
like this, In phase: primary red to dot, secondary red to dot. See in figure 8.
7. Figure 8. The dots are match
The phase relationships for voltage and current between primary and secondary
circuits of a transformer are direct: ideally, zero phase shift. The dot convention is a type
of polarity marking for transformer windings showing which end of the winding is which,
relative to the other windings.
The circuit polarity signs '+' and '-' indicate the relative polarities of the induced
voltages in both coils, i.e. how an instantaneous (sudden) magnetic field traversing the
primary and secondary coils induces a voltage in both coils. The instantaneous polarities of
the voltages across each inductor with respect to the dotted terminals are the same. The
circuit arrows indicate example applied and resultant relative current directions. The '+' and '-'
polarities in the diagram are not the voltages driving the currents. The instantaneous
directions of the current entering the primary inductor at its dotted end and the current
leaving of the secondary inductor at its dotted end are the same. Subtractive polarity
transformer designs are shown in the upper circuit diagrams. Additive polarity transformer
designs are shown in the lower circuit diagrams. Show in figure 9.
Figure 9. Subtractive and Additive Polarity in The Circuit Diagram
Thanks for read and good luck, be success. By Muhammad Kurniawan