This document discusses the proper procedure for paralleling two electrical systems. Five conditions must be matched: number of phases, direction of rotation, voltage amplitudes, frequencies, and phase angles. Phase rotation refers to whether the phases rotate clockwise or counterclockwise, and must be the same between systems. Phase angle refers to the timing of the voltage waveforms, which must be within 10 degrees of each other. The document provides examples of issues that can occur if these parameters are not properly matched, such as surges or the inability to close circuit breakers. Proper testing and verification of these parameters is necessary to safely parallel two electrical systems.
15-questions-retrofilling-transformers-fr3-insulectGraeme Smith
This document provides information on retrofilling transformers with FR3 natural ester fluid. It begins with an introduction to the benefits of retrofilling transformers, such as extending useful life. It then presents the top 15 frequently asked questions about retrofilling with FR3 fluid. The questions cover topics such as fluid miscibility, insulation regeneration ability, fire safety classifications, cold weather performance, and material compatibility. For each question, the document provides a concise answer and sometimes references additional resources for more detailed information.
Ampere's circuital law and its applicationsHaseeb Memon
Let's consider a bar of magnetic material (iron) placed in a uniform magnetic field of strength H. Ampere's law relates the net magnetic field along a closed loop to the electric current passing through the loop. It states that the integral of the magnetic field density B around any closed path is equal to the current enclosed by the path multiplied by the permeability of the medium. Ampere's law has various applications such as determining the magnetic field around a long, straight current-carrying wire.
Inductance of transmission line
Flux linkages of one conductor in a group of conductors
Inductance of composite conductor lines
Inductance of 3-phase overhead line
Bundled conductors
Construction of dc motor induction training programme-phase-isandippokharkar2007
The document discusses the construction of a DC motor. It describes the various parts of a DC motor including the yoke, eye bolt, field pole, armature core, armature winding, commutator, and brushes. The yoke carries magnetic flux between the poles and protects other parts. The field pole houses the field winding to generate a magnetic field when energized. The armature core has slots for the armature winding and develops torque. The commutator and brushes provide power to the armature winding to cause rotation.
This document provides an introduction to power system protection. It discusses the need for protection systems to detect and isolate faults to minimize damage. Short circuits can occur due to insulation failures, contamination, or mechanical issues. Protection systems aim to continue supply to the rest of the system while protecting faulty equipment. The types of protection discussed include fuses, overcurrent, differential, distance, and miscellaneous protections. Design criteria for protection systems include simplicity, economy, speed, reliability, sensitivity and selectivity. System protection components, zones of protection, and fault currents and voltages are also introduced.
Three common methods are used to measure power in three-phase circuits: the three-wattmeter method, two-wattmeter method, and single-wattmeter method. The three-wattmeter method uses three wattmeters to measure the power consumed by each load separately. The two-wattmeter method uses two wattmeters to measure the total power in a three-phase balanced or unbalanced load. The single-wattmeter method measures the power per phase and multiplies it by three to obtain the total power for a three-phase balanced star-connected load.
15-questions-retrofilling-transformers-fr3-insulectGraeme Smith
This document provides information on retrofilling transformers with FR3 natural ester fluid. It begins with an introduction to the benefits of retrofilling transformers, such as extending useful life. It then presents the top 15 frequently asked questions about retrofilling with FR3 fluid. The questions cover topics such as fluid miscibility, insulation regeneration ability, fire safety classifications, cold weather performance, and material compatibility. For each question, the document provides a concise answer and sometimes references additional resources for more detailed information.
Ampere's circuital law and its applicationsHaseeb Memon
Let's consider a bar of magnetic material (iron) placed in a uniform magnetic field of strength H. Ampere's law relates the net magnetic field along a closed loop to the electric current passing through the loop. It states that the integral of the magnetic field density B around any closed path is equal to the current enclosed by the path multiplied by the permeability of the medium. Ampere's law has various applications such as determining the magnetic field around a long, straight current-carrying wire.
Inductance of transmission line
Flux linkages of one conductor in a group of conductors
Inductance of composite conductor lines
Inductance of 3-phase overhead line
Bundled conductors
Construction of dc motor induction training programme-phase-isandippokharkar2007
The document discusses the construction of a DC motor. It describes the various parts of a DC motor including the yoke, eye bolt, field pole, armature core, armature winding, commutator, and brushes. The yoke carries magnetic flux between the poles and protects other parts. The field pole houses the field winding to generate a magnetic field when energized. The armature core has slots for the armature winding and develops torque. The commutator and brushes provide power to the armature winding to cause rotation.
This document provides an introduction to power system protection. It discusses the need for protection systems to detect and isolate faults to minimize damage. Short circuits can occur due to insulation failures, contamination, or mechanical issues. Protection systems aim to continue supply to the rest of the system while protecting faulty equipment. The types of protection discussed include fuses, overcurrent, differential, distance, and miscellaneous protections. Design criteria for protection systems include simplicity, economy, speed, reliability, sensitivity and selectivity. System protection components, zones of protection, and fault currents and voltages are also introduced.
Three common methods are used to measure power in three-phase circuits: the three-wattmeter method, two-wattmeter method, and single-wattmeter method. The three-wattmeter method uses three wattmeters to measure the power consumed by each load separately. The two-wattmeter method uses two wattmeters to measure the total power in a three-phase balanced or unbalanced load. The single-wattmeter method measures the power per phase and multiplies it by three to obtain the total power for a three-phase balanced star-connected load.
Reluctance is the opposition to magnetic flux in a magnetic circuit, analogous to resistance in an electric circuit. Reluctance is caused by properties of the magnetic material like length, cross-sectional area, and permeability. The reluctance of a non-uniform magnetic circuit is calculated by adding the reluctances of each uniform section. An air gap is often included to reduce saturation by increasing reluctance.
Inductance is the ability of a circuit to store energy in a magnetic field. It is caused by the self-inductance within a coil or mutual inductance between two linked coils. Inductors use this property to oppose changes in current flow. The standard unit for inductance is the henry.
The document discusses motion control systems and their applications. It covers the components of a motion control system including the application software, motion controller, amplifiers/drives, motors, mechanical elements, feedback devices and motion I/O. It also discusses common motion control functions like sequencing, speed control and point-to-point control. Finally, it discusses motion control variables like position, angle and speed and provides examples of motion profiles and multi-axis motion.
Dokumen tersebut membahas tentang struktur atom yang terdiri dari nukleus berisi proton dan neutron yang dikelilingi elektron. Juga membahas model atom, struktur kristal, ikatan kimia, dan model jalur energi yang berkaitan dengan sifat material."
Existen tres tipos principales de materiales magnéticos: paramagnéticos, diamagnéticos y ferromagnéticos. Los paramagnéticos se magnetizan en la misma dirección que el campo aplicado y pierden su magnetismo al retirar el campo. Los diamagnéticos se magnetizan en sentido contrario al campo y repelen los imanes. Los ferromagnéticos contienen dominios magnetizados que pueden alinearse con el campo aplicado, lo que permite crear imanes permanentes con ellos.
El documento describe conceptos básicos sobre circuitos trifásicos, incluyendo cómo se genera la energía trifásica usando tres bobinas separadas por 120°, las ventajas de los circuitos trifásicos sobre los monofásicos, y conceptos clave como voltajes de fase, secuencia de fase, y conexiones delta y Y. Explica cómo analizar circuitos trifásicos usando un equivalente monofásico y resuelve ejemplos numéricos que ilustran el cálculo de corrientes y voltajes en diferentes configuraciones.
Parámetros de las Líneas de Transmisión
DEFINICIÓN DE LÍNEA DE TRANSMISIÓN
MODELO CIRCUITAL DE LA LÍNEA BIFILAR IDEAL
Modelo RLGC
LÍNEAS BALANCEADAS Y DESBALANCEADAS
TIPOS DE LÍNEAS DE TRANSMISIÓN
Líneas de transmisión de conductor paralelo Línea de transmisión de cable abierto
Líneas de transmisión coaxial o concéntrica
PARAMETROS PRIMARIOS
Resistencia
Inductancia
Capacidad
Conductancia
PARAMETROS SECUNDARIOS
Modo de propagación
Constante de propagación
Impedancia característica
Atenuación
Absorción
Coeficiente de Reflexión
Ondas Incidentes y Reflejadas
Relación ondas estacionaria (ROE)
Sistemas de Comunicaciones
Ing. Gonzalo Verdaguer
ITU, Universidad Nacional de Cuyo
Praktikum 1 membahas modulasi amplitudo (AM) dan DSB-SC. Terdapat penjelasan teori dasar tentang AM dan DSB-SC beserta rumus matematisnya. Praktikum dilakukan dengan menggunakan modul COM3LAB untuk melihat gelombang dan spektrum sinyal hasil modulasi dengan berbagai bentuk gelombang input seperti sinus, kotak, dan segitiga.
This document discusses methods for measuring soil resistivity, which is an important factor in determining corrosion rates. It describes two key methods: (1) the Wenner four-pin method, where four pins are placed in the soil in a line and current is passed between the outer pins to measure voltage between the inner pins and calculate resistivity; and (2) the soil box method, where a soil sample is placed in a metal box and contacts make measurements to determine resistivity using the sample's dimensions. Both methods apply Ohm's Law and equations to calculate resistivity from resistance measurements. Temperature also affects resistivity, so measurements should not be taken below freezing.
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch.
The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. The low cost per unit, combined with its unique characteristic, have warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.[1] The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction transistor (PUT), is still widely available.
Voltage and Current Source foe Circuits and NetworksKetan Nayak
This document discusses voltage and current sources. It defines voltage as potential difference between two points in an electrical field and current as the flow of electric charge. Energy sources are categorized as either voltage sources or current sources. Voltage sources produce an electromotive force that causes current to flow independently of current. Current sources have infinite output resistance so current flow is independent of voltage. Ohm's law relates voltage, current, and resistance. Resistors oppose current flow. Kirchhoff's laws state that the sum of currents at a node is zero and the sum of voltages around a loop is zero.
CONSTRUCTION OF DC MACHINE, INDUCTION MACHINE & SYNCHRONOUS MACHINE|DAY 11|BA...Prasant Kumar
#CONSTRUCTION OF DC MACHINE
#DC MACHINE CONSTRUCTION IN HINDI
#INDUCTION MACHINE CONSTRUCTION IN HINDI
#SYNCHRONOUS MACHINE CONSTRUCTION IN HINDI
#CONSTRUCTION OF INDUCTION MACHINE
#CONSTRUCTION OF SYNCHRONOUS MACHINE
#CONSTRUCTION OF DC MOTOR
#CONSTRUCTION OF DC GENERATOR
#CONSTRUCTION OF INDUCTION MOTOR
#BASIC ELECTRICAL ENGINEERING
Electrical machine Day 11, Construction of DC, Induction motor, Synchronous generator, Synchronous motor, alternator, Basic Electrical Engineering
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle
EMF Equation of all machine
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
Electrical machine Day 11,Construction of DC, Induction motor, Synchronous generator, Synchronous motor,alternator,Basic Electrical Engineering
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle
EMF Equation of all machine
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
YOKE
It is the outermost part of a DC motor. It is made of cast iron or cast steel.
It provides mechanical protection to the inner parts of the machine.
Provide low reluctance path for the magnetic flux.
Pole core
These are made of cast steel laminations.
The main purpose is to hold the field windings .
The end portion of the pole is called pole shoe.
FIELD WINDING
They are enameled copper wires wound around the poles
When current passes through series connected windings then adjacent poles attain opposite polarity
Armature core
This is the rotating part of the machine
It is a cylindrical structure with slots around its outer periphery.
It houses conductors in the slots.
It provides easy path for magnetic flux
Thevenin's theorem states that a linear circuit containing sources and elements can be represented by a voltage source and resistance. It allows a complex circuit to be reduced to a simple series circuit. The four steps are: 1) remove the load, 2) determine voltage seen by load (Vth), 3) replace voltage source with short, 4) determine resistance seen by load (Rth). Using these steps, any linear circuit can be converted into a Thevenin equivalent circuit with a single voltage source and resistance.
- An autotransformer has a single winding that acts as both the primary and secondary winding. It uses less copper than a two-winding transformer, resulting in lower costs. However, it does not provide isolation between primary and secondary voltages.
- Key features include higher efficiency, smaller size, superior voltage regulation, and lower losses compared to a two-winding transformer. The output power depends on the transformation ratio. Savings in copper increases as the ratio approaches 1.
- Common three-phase transformer connections include star-star, delta-delta, star-delta, and delta-star, which determine how line voltages and currents are distributed across the windings.
self inductance , mutual inductance and coeffecient of couplingsaahil kshatriya
This document discusses self-inductance and mutual inductance. It defines self-inductance as the phenomenon where an induced electromotive force (emf) is created within a coil due to a change in the current passing through the coil. It also defines mutual inductance as the induced emf created in one coil due to a change in current in a neighboring coil. The document provides equations for calculating the mutual inductance between two coils based on their geometry and number of turns. It states that the mutual inductance depends on the number of turns in each coil, their cross-sectional area, and distance between them.
This document discusses Bravais lattices, which are infinite arrangements of points that describe the orderly structure of crystal lattices. It defines lattices and unit cells, and describes the 14 possible Bravais lattices in 2D and 3D space. These include cubic, tetragonal, orthorhombic, hexagonal, and triclinic systems. It also covers zone laws, which relate parallel crystal faces to zone axes following rules of addition. The document concludes that Bravais lattices were first described in 1842 and represent the 14 possible arrangements of points in 3D that can describe crystal structures.
El documento describe una máquina de fabricación de ladrillos impulsada por un motor de cuatro cilindros de 60 caballos de fuerza. Utiliza una transmisión por poleas con una configuración de banda en V. Se calcula un factor de seguridad de 1.36 y una vida estimada de más de 678,000 horas.
Se describe el principio de funcionamiento de los reguladores de voltaje lineales en serie. Además, se muestran varios ejemplos explicando cómo funcionan los circuitos electrónicos y se agregan ecuaciones donde se resuelve paso por paso el circuito.
In the presentation all about, the operation of Parallel System of two alternators and in the sense how in power plants, they utilize it in their sensitivity to produce more electricity at one operation and after all how they reduce the per cost of electricity unit. I hope, this presentation helpfull to all the Engineering Students.
Offset is a sustained deviation of the process variable from the setpoint.
A load disturbance is an undesired change in one of the factors that can affect the setpoint.
This document outlines requirements for testing main and auxiliary steering gear before departure, including operating all components and controls. It also requires emergency steering drills every 3 months to practice procedures. Officers must be trained in steering gear operation and maintenance, and records must be kept of tests and drills conducted. Ships on short voyages may have reduced testing requirements of at least once a week.
Reluctance is the opposition to magnetic flux in a magnetic circuit, analogous to resistance in an electric circuit. Reluctance is caused by properties of the magnetic material like length, cross-sectional area, and permeability. The reluctance of a non-uniform magnetic circuit is calculated by adding the reluctances of each uniform section. An air gap is often included to reduce saturation by increasing reluctance.
Inductance is the ability of a circuit to store energy in a magnetic field. It is caused by the self-inductance within a coil or mutual inductance between two linked coils. Inductors use this property to oppose changes in current flow. The standard unit for inductance is the henry.
The document discusses motion control systems and their applications. It covers the components of a motion control system including the application software, motion controller, amplifiers/drives, motors, mechanical elements, feedback devices and motion I/O. It also discusses common motion control functions like sequencing, speed control and point-to-point control. Finally, it discusses motion control variables like position, angle and speed and provides examples of motion profiles and multi-axis motion.
Dokumen tersebut membahas tentang struktur atom yang terdiri dari nukleus berisi proton dan neutron yang dikelilingi elektron. Juga membahas model atom, struktur kristal, ikatan kimia, dan model jalur energi yang berkaitan dengan sifat material."
Existen tres tipos principales de materiales magnéticos: paramagnéticos, diamagnéticos y ferromagnéticos. Los paramagnéticos se magnetizan en la misma dirección que el campo aplicado y pierden su magnetismo al retirar el campo. Los diamagnéticos se magnetizan en sentido contrario al campo y repelen los imanes. Los ferromagnéticos contienen dominios magnetizados que pueden alinearse con el campo aplicado, lo que permite crear imanes permanentes con ellos.
El documento describe conceptos básicos sobre circuitos trifásicos, incluyendo cómo se genera la energía trifásica usando tres bobinas separadas por 120°, las ventajas de los circuitos trifásicos sobre los monofásicos, y conceptos clave como voltajes de fase, secuencia de fase, y conexiones delta y Y. Explica cómo analizar circuitos trifásicos usando un equivalente monofásico y resuelve ejemplos numéricos que ilustran el cálculo de corrientes y voltajes en diferentes configuraciones.
Parámetros de las Líneas de Transmisión
DEFINICIÓN DE LÍNEA DE TRANSMISIÓN
MODELO CIRCUITAL DE LA LÍNEA BIFILAR IDEAL
Modelo RLGC
LÍNEAS BALANCEADAS Y DESBALANCEADAS
TIPOS DE LÍNEAS DE TRANSMISIÓN
Líneas de transmisión de conductor paralelo Línea de transmisión de cable abierto
Líneas de transmisión coaxial o concéntrica
PARAMETROS PRIMARIOS
Resistencia
Inductancia
Capacidad
Conductancia
PARAMETROS SECUNDARIOS
Modo de propagación
Constante de propagación
Impedancia característica
Atenuación
Absorción
Coeficiente de Reflexión
Ondas Incidentes y Reflejadas
Relación ondas estacionaria (ROE)
Sistemas de Comunicaciones
Ing. Gonzalo Verdaguer
ITU, Universidad Nacional de Cuyo
Praktikum 1 membahas modulasi amplitudo (AM) dan DSB-SC. Terdapat penjelasan teori dasar tentang AM dan DSB-SC beserta rumus matematisnya. Praktikum dilakukan dengan menggunakan modul COM3LAB untuk melihat gelombang dan spektrum sinyal hasil modulasi dengan berbagai bentuk gelombang input seperti sinus, kotak, dan segitiga.
This document discusses methods for measuring soil resistivity, which is an important factor in determining corrosion rates. It describes two key methods: (1) the Wenner four-pin method, where four pins are placed in the soil in a line and current is passed between the outer pins to measure voltage between the inner pins and calculate resistivity; and (2) the soil box method, where a soil sample is placed in a metal box and contacts make measurements to determine resistivity using the sample's dimensions. Both methods apply Ohm's Law and equations to calculate resistivity from resistance measurements. Temperature also affects resistivity, so measurements should not be taken below freezing.
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch.
The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. The low cost per unit, combined with its unique characteristic, have warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.[1] The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction transistor (PUT), is still widely available.
Voltage and Current Source foe Circuits and NetworksKetan Nayak
This document discusses voltage and current sources. It defines voltage as potential difference between two points in an electrical field and current as the flow of electric charge. Energy sources are categorized as either voltage sources or current sources. Voltage sources produce an electromotive force that causes current to flow independently of current. Current sources have infinite output resistance so current flow is independent of voltage. Ohm's law relates voltage, current, and resistance. Resistors oppose current flow. Kirchhoff's laws state that the sum of currents at a node is zero and the sum of voltages around a loop is zero.
CONSTRUCTION OF DC MACHINE, INDUCTION MACHINE & SYNCHRONOUS MACHINE|DAY 11|BA...Prasant Kumar
#CONSTRUCTION OF DC MACHINE
#DC MACHINE CONSTRUCTION IN HINDI
#INDUCTION MACHINE CONSTRUCTION IN HINDI
#SYNCHRONOUS MACHINE CONSTRUCTION IN HINDI
#CONSTRUCTION OF INDUCTION MACHINE
#CONSTRUCTION OF SYNCHRONOUS MACHINE
#CONSTRUCTION OF DC MOTOR
#CONSTRUCTION OF DC GENERATOR
#CONSTRUCTION OF INDUCTION MOTOR
#BASIC ELECTRICAL ENGINEERING
Electrical machine Day 11, Construction of DC, Induction motor, Synchronous generator, Synchronous motor, alternator, Basic Electrical Engineering
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle
EMF Equation of all machine
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
Electrical machine Day 11,Construction of DC, Induction motor, Synchronous generator, Synchronous motor,alternator,Basic Electrical Engineering
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle
EMF Equation of all machine
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
YOKE
It is the outermost part of a DC motor. It is made of cast iron or cast steel.
It provides mechanical protection to the inner parts of the machine.
Provide low reluctance path for the magnetic flux.
Pole core
These are made of cast steel laminations.
The main purpose is to hold the field windings .
The end portion of the pole is called pole shoe.
FIELD WINDING
They are enameled copper wires wound around the poles
When current passes through series connected windings then adjacent poles attain opposite polarity
Armature core
This is the rotating part of the machine
It is a cylindrical structure with slots around its outer periphery.
It houses conductors in the slots.
It provides easy path for magnetic flux
Thevenin's theorem states that a linear circuit containing sources and elements can be represented by a voltage source and resistance. It allows a complex circuit to be reduced to a simple series circuit. The four steps are: 1) remove the load, 2) determine voltage seen by load (Vth), 3) replace voltage source with short, 4) determine resistance seen by load (Rth). Using these steps, any linear circuit can be converted into a Thevenin equivalent circuit with a single voltage source and resistance.
- An autotransformer has a single winding that acts as both the primary and secondary winding. It uses less copper than a two-winding transformer, resulting in lower costs. However, it does not provide isolation between primary and secondary voltages.
- Key features include higher efficiency, smaller size, superior voltage regulation, and lower losses compared to a two-winding transformer. The output power depends on the transformation ratio. Savings in copper increases as the ratio approaches 1.
- Common three-phase transformer connections include star-star, delta-delta, star-delta, and delta-star, which determine how line voltages and currents are distributed across the windings.
self inductance , mutual inductance and coeffecient of couplingsaahil kshatriya
This document discusses self-inductance and mutual inductance. It defines self-inductance as the phenomenon where an induced electromotive force (emf) is created within a coil due to a change in the current passing through the coil. It also defines mutual inductance as the induced emf created in one coil due to a change in current in a neighboring coil. The document provides equations for calculating the mutual inductance between two coils based on their geometry and number of turns. It states that the mutual inductance depends on the number of turns in each coil, their cross-sectional area, and distance between them.
This document discusses Bravais lattices, which are infinite arrangements of points that describe the orderly structure of crystal lattices. It defines lattices and unit cells, and describes the 14 possible Bravais lattices in 2D and 3D space. These include cubic, tetragonal, orthorhombic, hexagonal, and triclinic systems. It also covers zone laws, which relate parallel crystal faces to zone axes following rules of addition. The document concludes that Bravais lattices were first described in 1842 and represent the 14 possible arrangements of points in 3D that can describe crystal structures.
El documento describe una máquina de fabricación de ladrillos impulsada por un motor de cuatro cilindros de 60 caballos de fuerza. Utiliza una transmisión por poleas con una configuración de banda en V. Se calcula un factor de seguridad de 1.36 y una vida estimada de más de 678,000 horas.
Se describe el principio de funcionamiento de los reguladores de voltaje lineales en serie. Además, se muestran varios ejemplos explicando cómo funcionan los circuitos electrónicos y se agregan ecuaciones donde se resuelve paso por paso el circuito.
In the presentation all about, the operation of Parallel System of two alternators and in the sense how in power plants, they utilize it in their sensitivity to produce more electricity at one operation and after all how they reduce the per cost of electricity unit. I hope, this presentation helpfull to all the Engineering Students.
Offset is a sustained deviation of the process variable from the setpoint.
A load disturbance is an undesired change in one of the factors that can affect the setpoint.
This document outlines requirements for testing main and auxiliary steering gear before departure, including operating all components and controls. It also requires emergency steering drills every 3 months to practice procedures. Officers must be trained in steering gear operation and maintenance, and records must be kept of tests and drills conducted. Ships on short voyages may have reduced testing requirements of at least once a week.
The document describes the operation of a four-stroke engine, including the intake, compression, power, and exhaust strokes in one revolution of the crankshaft. It also discusses the valve timing and fuel injection systems. The cooling, lubrication, and timing systems are described as well as differences between gasoline and diesel engines.
Diesel engines on ships can run on various fuels including heavy fuel oil, marine diesel oil, and intermediate fuel oil. Heavy fuel oil is stored in bunker tanks and passes through settling tanks, heaters, separators, and daily service tanks before being pumped to the engine. Marine diesel oil is stored separately and also passes through purification processes before storage and pumping to the engine. A mixing tank is used for gradual transition between fuels and includes vents for hot fuel fumes.
The document describes the paralleling technique for dental radiography. In the paralleling technique, the film, teeth, and aiming ring of the paralleling instrument are positioned parallel to each other. This allows the x-ray beam to be perpendicular to the film and teeth, reducing distortion. The paralleling technique provides better dimensional accuracy compared to the bisecting angle technique but is less comfortable for patients. Proper patient positioning, film selection and placement, use of paralleling instruments, and head position are described to successfully implement this technique.
The cylinder liner forms the cylindrical space in the engine where the piston reciprocates. It is manufactured separately from the cylinder block using an alloy that has better wear resistance at high temperatures. This allows for replacement of just the liner if it wears. The liner is cooled, often with tangential bore cooling, to maintain an optimal temperature for lubrication and reducing thermal stresses. Proper lubrication and minimizing abrasive particles are important to reduce liner wear over the life of the engine.
Dokumen ini membahas tentang sistem bahan bakar minyak kapal dan jenis-jenis bahan bakar diesel yang digunakan pada kapal, yaitu Marine Gas Oil (MGO), Marine Diesel Oil (MDO), dan Marine Fuel Oil (MFO). Dokumen ini juga menjelaskan proses perawatan bahan bakar minyak yang meliputi treatment, pembersihan filter, pemanasan, pengendapan, dan pemilihan bahan bakar yang sesuai. Proses pemanasan dilakukan untuk menyesuaikan vis
Dokumen ini membahas tentang defleksi poros engkol pada mesin kapal, termasuk cara mengukur deflesinya menggunakan alat clock meter, faktor yang mempengaruhinya, dan pedoman pengukuran.
The document defines and describes 18 key parts and areas of a ship. It includes definitions for areas like the bridge, which is where the ship is commanded from, as well as parts like the bulbous, which modifies water flow around the hull. Other parts defined are the bow thruster, forecastle, funnel, rudder, main deck, hull, super structure, portside, bulkhead, bottom, holds, waterline, tween deck, and starboard side.
The document discusses various piping systems on ships including bilge, ballast, air/sounding, firefighting, fuel oil, lubricating oil, cooling water, compressed air, domestic water, steam, and cargo systems. Key details provided include requirements for pump capacities, pipe sizing formulas, tank arrangements, safety features such as quick closing valves and alarms, and material considerations for high pressure/temperature applications.
Out of phase current switching in High Voltage Circuit BreakersAli Sepehri
Out-of-phase switching occurs when two power systems or a generator and power system are connected with a phase angle difference between their voltages. This causes out-of-phase currents that a circuit breaker must interrupt. The transient recovery voltage (TRV) under out-of-phase conditions has a very high peak but moderate rate of rise and current. Examples where out-of-phase switching may occur include accidentally connecting a generator at the wrong phase angle or two power systems losing synchronization due to a fault. Proper protection, synchronization, and circuit breaker design are needed to safely handle out-of-phase switching conditions.
POWER QUALITY IMPROVEMENT AND FAULT RIDE THROUGH OF GRID CONNECTED WIND ENE...Bharadwaj S
This work tries to improve the power quality by compensating reactive power with Active Power Filters and also to analyze Fault Ride Through of Grid connected wind energy conversion systems.
1) The document discusses improving power quality and fault ride through capability of grid connected wind energy conversion systems.
2) It aims to compensate reactive power using active power filters to improve power quality and analyze the fault ride through of grid connected wind turbines.
3) A crowbar protection scheme is analyzed to enhance the system's power quality and meet grid code requirements by controlling the doubly fed induction generator through vector control strategies.
- Any abnormal condition that causes excessive current flow through unintended paths in a power system is defined as a fault.
- Faults can be caused by insulation failures, lightning strikes, or accidental operations and must be safely disconnected to prevent equipment damage.
- Short circuit current calculations are required to select properly rated circuit breakers and relay settings for protection schemes.
- Faults are classified by nature, participating phases, and whether they are symmetrical or asymmetrical. Symmetrical faults can be analyzed using positive sequence networks while unsymmetrical faults require symmetrical component analysis.
Power Circuits and Transforers-Unit 3 Labvolt Student Manualphase3-120A
This document discusses determining equivalent capacitance for series and parallel capacitors. It explains that capacitance opposes changes in voltage across capacitor terminals and depends on factors like dielectric material and plate size/spacing. The exercise objectives are to calculate equivalent capacitance using circuit measurements and explain how capacitance values combine in series and parallel configurations.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document discusses how to properly parallel and synchronize DC and AC electrical systems, including:
1) DC systems are paralleled by ensuring voltages are similar before closing the breaker to avoid circulating currents.
2) Single phase AC supplies are synchronized by matching frequency, voltage, phase, and polarity between the generator and grid using a synchroscope and voltmeters before closing the breaker.
3) Three phase AC systems require matching frequency, voltage, phase, and polarity as well as ensuring consistent phase rotation (RWB) between systems to avoid damage when the breaker is closed.
Catastrophic failure of system equipment during switching of 115kV shunt reac...rannaluru
A 115 kV circuit switcher and disconnect switch failed during the opening of an 80 MVAR shunt reactor. Simulations using ATP-EMTP showed the transient recovery voltage across the circuit switcher could have exceeded its withstand capability due to prolonged arcing from potential low SF6 pressure. The circuit switcher was replaced with a mechanically staggered circuit breaker and synchronous switching control to target current zeros during opening and improve withstand of transients. However, lack of data prevented conclusively determining the root cause of failure.
In the modern power system the reactive power compensation is one of the main issues, the transmission of active power requires a difference in angular phase between voltages at the sending and receiving points (which is feasible within wide limits), whereas the transmission of reactive power requires a difference in magnitude of these same voltages (which is feasible only within very narrow limits). The reactive power is consumed not only by most of the network elements, but also by most of the consumer loads, so it must be supplied somewhere. If we can't transmit it very easily, then it ought to be generated where it is needed." (Reference Edited by T. J. E. Miller, Forward Page ix).Thus we need to work on the efficient methods by which VAR compensation can be applied easily and we can optimize the modern power system. VAR control technique can provides appropriate placement of compensation devices by which a desirable voltage profile can be achieved and at the same time minimizing the power losses in the system. This report discusses the transmission line requirements for reactive power compensation. In this report thyristor switched capacitor is explained which is a static VAR compensator used for reactive power management in electrical systems.
Seminar Topic For Electrical and Electronics Engineering (EEE)
François D. Martzloff's document discusses the protection of industrial electronics and power conversion equipment from power supply and data line disturbances. It begins with an overview of the origins and sources of surges from lightning, power switching, and ground potential differences. It then provides a brief tutorial on surge propagation and fundamental protection approaches. The document gives examples of applying this knowledge to address specific protection questions and avoid common pitfalls.
IRJET- PI Controller based Shunt Connected Three Phase Active Power FilterIRJET Journal
This document describes a simulation of a shunt active power filter with a PI controller to mitigate current harmonics from nonlinear loads. It begins with an introduction to power quality issues caused by nonlinear loads and an overview of active power filters. It then describes the system configuration, including the PI controller used to regulate the DC link voltage of the active power filter inverter. Simulation results in MATLAB/Simulink show the PI controller is effective at eliminating current harmonics on the source side, improving the power factor to near unity and reducing the total harmonic distortion to 2.22%. The system is concluded to offer fast compensation of current harmonics and improved power quality through use of the shunt active power filter with PI control.
Power Quality Enhancement in an Isolated Power System Using Series CompensationIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
The primary focus of the journal is on Information Technology and Computer Engineering. This suggests that the journal covers a wide range of topics within these disciplines.
Power Circuits and Transforers-Unit 6 Labvolt Student Manualphase3-120A
This document provides instruction on analyzing balanced three-phase AC circuits connected in wye and delta configurations. It discusses the differences between line and phase voltages and currents. Formulas are presented for calculating active, reactive, and apparent power in balanced three-phase circuits. Exercises are included to measure voltages and currents in wye- and delta-connected resistive loads to verify the theoretical calculations and relationships between line and phase values.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document discusses different types of current and voltage transformers used in power systems. It provides details on:
- Voltage transformers, which operate in shunt mode by applying the system voltage across their input terminals. They are designed to produce an accurate scaled down replica of the input voltage.
- Sources of error in voltage transformers like ratio and phase errors. Standards for accuracy classes and requirements for protection purposes where accuracy is important during faults.
- Construction aspects like insulation for system voltages and mechanical design to withstand short circuits. Protection of the primary and secondary windings.
- Residually connected voltage transformers which can measure the residual voltage under unbalanced conditions by connecting the secondary windings in a broken delta configuration
This document discusses a study on using a Unified Power Quality Conditioner (UPQC) to improve power quality issues. The UPQC is a device that uses both series and shunt active power filters to compensate for voltage and current related problems simultaneously. The study uses MATLAB simulation to demonstrate how a UPQC model can reduce the total harmonic distortion (THD) in the source voltage, source current, and load voltage caused by nonlinear loads. Control strategies like synchronous reference frame (SRF) theory are applied to the UPQC operation. The document provides background on power quality issues like voltage sag, swell, harmonics, and waveform distortion. It also describes the basic configuration, design, and control methods of the UPQC using S
Impacts of Distributed Generation on Power QualityParth Patel
This paper studies the impacts of distributed generation, specifically solar and wind power, on power quality when interconnected to a distribution utility feeder. Multiple scenarios were modeled and simulated using the RSCAD/RTDS real-time simulation tool. The results show some increase in harmonic distortion and voltage fluctuations with the addition of distributed generation, but within acceptable limits. Harmonics were observed at higher orders which could impact power quality. Voltage fluctuations increased nearer to the distributed generation sources.
Similar to A practical primer for paralleling electric systems (20)
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
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.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Embedded machine learning-based road conditions and driving behavior monitoring
A practical primer for paralleling electric systems
1. Winter 2004-2005 1
T
he time-worn method of paralleling two electrical systems by con-
necting them and throwing the switch can be improved upon by
application of a little practical knowledge. The consequences of
uncontrolled releases of electrical energy resulting from connecting two
unsynchronized systems is adequate incentive to adopt a more rigorous
strategy than throwing the switch and hoping it works. This article pro-
vides suggestions for improving the odds of success when connecting
two electrical systems. Included is an introduction to the parameters of
synchronization which must be considered before paralleling two electri-
cal systems. The reader can gain a broader understanding of the often-
misunderstood terms of phase rotation and phase sequence. Additionally, a
few real-life examples supplement the technical arguments and provide
a greater understanding.
Woodward defines synchronization as the matching of the output-volt-
age waveform of one ac electrical generator with the voltage waveform
of another ac electrical system. For two systems to be synchronized, five
conditions must be matched:
• Number of phases in each system
• Direction of rotation of these phases
• Voltage amplitudes of the two systems
• Frequencies of the two systems
• Phase angle of the voltage of the two systems.
The number of phases, voltage level, and frequency are established by
long-standing practice. Electrical power is typically either single-phase
or three-phase, and voltage magnitudes are determined by utility energy
providers and equipment suppliers. Frequency in this country is fixed
at 60 hertz. These three criteria for
paralleling are, for the most part,
taken for granted. However, one
of the most confusing and frus-
trating discussions centers on the
direction of rotation.
The following is a situation en-
countered when designing an on-
site generation facility for a large
commercialcomplex.Attheservice
entrance equipment, the incoming
utility-owned cubicle was marked
with anACB phase rotation, while
in the adjacent customer-owned
cubicle the phase rotation became
ABC. This system parameter was
displayed on the switchgear draw-
ings with a suitable hieroglyphic to
make the situation clear to anyone
Special Feature
A Practical Primer
for Paralleling Electric Systems
by David Charles
ESCO
2. 2 NETA WORLD
interested in determining the phase rotation. What
follows is taken directly from actual drawings:
Fortunately, phase rotation only has two choices
— clockwise and counterclockwise. In a three-phase
system, phases are represented as electrically 120 de-
grees apart and named A, B, and C. These phases are
said to rotate in a counterclockwise direction. Their
sequence refers to the order the phases appear pass-
ing a stationary point of observation. For the phase
rotation or phase sequence ABC, phase B lags phase
A by 120 degrees, and phase C lags phase B by 120
degrees. For the alternative ACB, phase C lags phase
A by 120 degrees, and phase B lags phase C by 120
degrees.Atechnician can hook up a rotation meter and
determine from the meter if the electric system has a
clockwise or counterclockwise rotation. The technician
can then measure the generator and evaluate whether
the phase sequence or phase rotation of the generator
and the electric system are the same.
Matching phase sequence can not be be evaluated
solely by inspecting the appropriate physical connec-
tions at the various electric sources. Many engineering
professionals promote that correct phasing can be ac-
complished by carefully marking and testing power
cables during the installation process. This would
eliminate phase rotation or phase sequence errors
caused only by transitions during connection. Unfor-
tunately, too many opportunities exist for swapped
phases, incorrectly marked cables, and incorrectly
marked equipment from the manufacturer. As a case
in point, during a recent generator installation at an
industrial plant, measurements of the incoming-utility
phase rotation with a phase rotation meter found the
utility service’s phase sequence to beABC. The genera-
tor was started up, and the synchronizer brought the
two systems into what appeared to be parallel by the
synchroscope, but the generator tie breaker would not
close. While troubleshooting this issue, the voltages
across the tie breaker stabs were measured and were
determined to have potential between the respective
phases that appeared by the controls to be matched.
The Woodward SPM synchronizer and the synchro-
scope of the generator controls indicated that the two
sources were matched. The generator breaker was
tripped and locked out, and the generator tie breaker
was then closed which effectively back-fed the genera-
tor circuit. The phase rotation at the load side of the
generator breaker was measured. The phase rotation
was ABC. With the generator breaker still locked out,
the generator was started with the phase rotation mea-
sured ACB on the line side of the generator breaker.
The phase rotation of a generator, when received
from the manufacturer, is typically configured with
an ABC rotation. Evidently, the generator leads had
been incorrectly connected to the generator breaker
while in the factory.
When two or more electrical power sources are
paralleled to the same power distribution system,
the power sources must be synchronized correctly.
Yet predicting and designating the phase rotation in
a situation like this is problematic. The actual phase
rotation must be determined. Otherwise, when the
tie breaker is closed, power surges and mechanical
or electrical stresses will result. One system has the
potential of placing a dead short on the other. The
voltages between the two systems can also be twice
the peak operating voltage.
Each source being paralleled must be connected
so that all phases rotate in the same direction. If the
phase rotation is not the same, only one phase can be
synchronized. It helps to visualize this in the form of
a diagram, also found in Woodward:
Phase A of the generator matches phase A of the
electric system, but phase B and phase C of the respec-
tive systems do not match. Typically, synchronization
is accomplished with one potential transformer on
each system, but matching one phase does not bring
the systems into parallel. The phase rotation or phase
sequence of each system must match!
3. Winter 2004-2005 3
Typically, the second most confusing and misrep-
resented aspect of the paralleling process is phase
angle. Phase angle match refers to the phase relation-
ship between voltages of the systems to be paralleled.
Both the voltage magnitudes and the corresponding
voltage phases of the two systems must match to be
in synch with each other. More specifically, the voltage
wave forms should be within ± 10 degrees to avoid
heavy surge currents during paralleling. Again, a
diagram from Woodward tells the story much better
than words:
phases of the two systems to be paralleled, the line-to-
line potential to the other phases should approximate
the system voltage. For safety reasons, the meter to
be used for performing this measurement should be
rated for the voltage being measured.Additionally, do
not assume that using the secondary metering as an
alternative to measuring the actual potentials across
the open point is adequate. The Woodward SPM syn-
chronizer states that the source is in synch when the
lights are out on the synch scope. However, it is still
highly recommended that this voltage measurement
be performed. The single most important requirement
in the paralleling process is zero potential between
the corresponding phases to be connected on closing
the circuit.
Having now obtained a basic knowledge of the
technical issues involved in paralleling two electric
systems, it is apparent that no errors of judgment can
be permitted when commissioning circuitry for par-
alleling two electrical systems. Never disconnect or
disable applicable protective relaying when connect-
ing two sources in parallel. In fact, don’t even try to
close the connecting device without being confident
the protective relaying will operate. Make testing
and verifying the protective relay operation a prior-
ity before closing the device as part of the paralleling
process. Many utilities and industrial users will hire an
independent testing firm to test protective relaying as
part of the commissioning process of new facilities to
avoid the bias of those involved with the design and
construction effort.
Many opportunities exist for a nuisance trip in the
process of bringing a new generator installation on
line. Further, the ultimate user of the electrical energy
typically does not tolerate more than one outage for
accomplishing a tie in to their system. This results in
a temptation to lift the trip circuit of the protective
device. This is not recommended. The risk of serious
damage or potential electrical flashover as a result is
too great. Electrical surges have resulted in electrical
fires during the commissioning process. The typical
cause of the problem is that the protective relaying was
disabled or not allowed to operate. If outages cannot
be tolerated, the start-up process should be resched-
uled for a period when an outage can be tolerated.
A final word with respect to commissioning ac-
tivities associated with parallel generation activities:
make certain the shorting screws are removed from the
currrent transformer blocks and all fuses are restored
to their respective holders prior to performing opera-
tional testing. You would be surprised to know how
many times attempts to parallel systems have failed
due to the synchronizing potential transformer fuse
having been removed and not reinstalled.
For this diagram, the waveforms represent the same
phase of each system – in this case the generator and
the bus voltage. The generator voltage is lagging the
bus voltage by about 120 degrees, and attempting to
parallel these electrical sources at this point might
damage the generator. In reality, the bus or utility
source would pull the generator into synch once the
breaker is closed. Unfortunately, the generator shaft
might turn 120 degrees relative to the engine shaft
in the process. For a synchronous generator, phase
matching is usually accomplished by controlling the
speed of the oncoming generator’s prime mover once
the frequencies of the two systems are nearly matched.
Note that there are many documented cases of damage
caused by failure to match phase angles.
Amunicipal utility was generating at 480 volts and
hadanoptionofsteppinguptothedistributionvoltage
of 4160 volts through one tie breaker or paralleling a
12.5-kilovolt utility source with another step-up trans-
former and tie breaker. Typically, the generator speed
is adjusted to enable the systems to parallel. The utility
personnel could parallel to one source or the other,
but they could never get the generators paralleled to
both sources, simultaneously. Through investigation,
it was determined that one step-up transformer was a
delta-delta connection and the other was a delta-wye
connection. This resulted in a 30-degree phase shift
which could not be resolved through generator speed
adjustment. The ultimate solution in this case was to
replace one of the transformers, thus enabling the util-
ity to feed both buses simultaneously.
Akey measurement for paralleling two electric sys-
tems is the potential difference between the respective
phases. No significant potential must exist between
what are thought to be the same phases of each sys-
tem to be connected together. Further, if the measure-
ments yield near-zero potential between the respective
4. 4 NETA WORLD
In summary, for two systems to be synchronized
and operated in parallel, five conditions must be
matched:
• Number of phases in each system
• Direction of rotation of these phases
• Voltage amplitudes of the two systems
• Frequencies of the two systems
• Phase angle of the voltage of the two systems.
The number of phases, voltage level, and frequency
are established by long-standing practice and easily
addressed through design and field measurement.
Further, each source being paralleled must be con-
nected so that all phases rotate in the same direction,
and the voltage waveforms for each electrical source
must be within a minimum of ± 10 degrees. This re-
quires that the phase rotation and phase angles be
verified during the commissioning process. Finally,
safety should always be considered during commis-
sioning activities. Test equipment should be rated for
the voltages being measured. Additionally, the pro-
tective relays associated with the system should be
verified as operable and functioning prior to actually
tying the systems together.
References
1. Woodward Governor Company, 2004, “Governing
Fundamentals and Power Management,” Woodward
Reference Manual 26260.
David Charles is a professional engineer in electrical engineer-
ing. He is also a Senior Project Manager at ESCO Energy Services
Company with over 20 years of experience in energy projects for
industrial, commercial, and utility clients. His project experience
includes over 200 megawatts of turnkey generation facilities, trans-
mission and distribution line design and construction, substations,
SCADA systems, metering systems, and protective relaying and
control systems. He also has extensive experience in fault current
and coordination studies, arc flash analysis, and substation equip-
ment testing and commissioning.