Electrical terminology
1 Active power - the part of the energy used to convert into electromagnetic form during the process of transmitting and transmitting AC power is called active power.
2 Reactive power - the part of the energy used for the exchange of electromagnetic fields in the circuit during the process of transmitting and receiving AC power is called reactive power.
3 Power system - The whole system consisting of generators, power distribution units, boost and step-down substations, power lines and power users is called the power system. Neutral point displacement: In the case of a three-phase circuit, when the three-phase load of the power supply voltage is symmetrical, if the three-phase load is also symmetrical, the neutral point voltage is zero regardless of the presence or absence of a neutral point. However, if the three-phase load is asymmetrical and there is no neutral or neutral impedance, the voltage will appear at the neutral point. This phenomenon is called the neutral point displacement phenomenon.
4 operation overvoltage - transient voltage rise caused by circuit breaker switching operation and short circuit or ground fault, called operation over voltage;
5 Resonant overvoltage - due to the operation of the circuit breaker, the grid loop is divided or the core component tends to be saturated, causing the inductive reactance and capacitive reactance of a loop to meet the resonance condition, and the voltage rise that may cause resonance is called resonance. Voltage.
6 Electrical main wiring—mainly refers to a circuit designed to transmit electrical energy in a power plant, substation, and power system, designed to meet predetermined power transmission modes and operation requirements, indicating the interconnection relationship between high voltage electrical equipment. .
7 double busbar connections - it has two sets of busbars: working busbar I and spare busbar l. Each circuit is connected to two sets of busbars via a circuit breaker and two sets of isolating switches. The busbars are connected by busbar connection breakers (referred to as busbars), which are called double busbars.
8 One and a half circuit breaker wiring - each two components (outlet or power supply) is connected in series with three circuit breakers to two sets of busbars, called a half circuit breaker wiring, also known as 3/2 wiring.
9 plant power - in the process of starting, running, decommissioning and overhauling, there are a large number of mechanical equipment driven by electric motor to ensure the main equipment of the unit and coal, coal, ash, dust and water Handling the normal operation of auxiliary equipment. These electric motors and the electrical equipment for operation, operation, testing, overhaul, lighting, etc. of the whole plant belong to the factory load, and the total power consumption is collectively referred to as the factory power.
10 plant power consumption rate - the percentage of power consumption of the plant to the total power generation of the power plant is called the plant power consumption rate. The plant electricity rate is one of the main economic indicators for power plant operation.
11 Frequent load – the motor that is used continuously for continuous operation every day;
12 Infrequent load - load used only during maintenance, accidents or start and stop of the furnace; ''
13 continuous load - load for more than 2 hours per continuous operation;
14 short-time load - load only 10 - 120min at a time;
15 intermittent load - repeated cyclical work, which does not exceed 10 minutes of load per cycle.
16 Self-starting of the motor - the motor that runs normally in the factory system. "When the voltage of the power supply busbar suddenly disappears or drops significantly, it will drop a lot at the end of its speed after a short period of time (usually 0.5-1.5 s). Monk
Before the power is stopped, the bus voltage of the factory is restored to normal (such as power failure troubleshooting or automatic backup of the standby power supply), the motor will accelerate itself and return to normal operation. This process is called self-starting of the motor.
17 Loss of magnetism - sudden or partial loss of excitation of a synchronous generator is called loss of magnetism
18 Excitation Control System - The entire system consisting of the excitation regulator, the excitation power unit and the generator itself is called the excitation control system.
19 Self-excited static excitation system - using a transformer connected to the generator outlet. (called the excitation transformer ') as the excitation power supply, which is rectified by silicon and then supplied to the generator for excitation. Since the excitation transformer is connected in parallel to the generator outlet, this excitation mode is called self-excitation mode, and the excitation transformer and rectifier are all stationary components, so it is also called self-excited static excitation system.
20 transformers - sensors that obtain electrical primary loop information from secondary equipment such as measuring instruments, relay protection and automatic devices in the power system. The function of the transformer is to convert high voltage and large current into low voltage and small current.
21 SF6 circuit breaker - a circuit breaker using SFe gas with excellent arc extinguishing performance and insulation properties as an arc extinguishing medium, called SF 6 circuit breaker. It has the characteristics of strong breaking capacity and small volume, but the structure is more complicated, and the metal consumption is large and the price is relatively expensive.
22 Vacuum Circuit Breaker - A circuit breaker that uses a high dielectric strength of vacuum to extinguish an arc, called a vacuum circuit breaker. The circuit breaker has the characteristics of fast arc extinguishing speed, non-oxidation of the contact material, long service life and small volume.
23 working grounding - is to ensure the grounding required for the normal operation of the power system. For example, the neutral point of the transformer in the neutral point direct grounding system is used to stabilize the grid to ground potential, thereby reducing the insulation to ground.
24 lightning protection grounding - is the grounding set for the needs of lightning protection. For example, lightning rod (wire), lightning arrester grounding, the purpose is to make lightning current smoothly into the earth, in order to help reduce the lightning overvoltage, it is also known as overvoltage protection grounding.
25 Protective earthing - also known as safety grounding, is the grounding for personal safety, that is, the outer casing of the electrical equipment (including the cable skin) must be grounded to prevent the electrical insulation of the outer casing from endangering personal safety.
26 Instrument Control Grounding—The grounding of the power control system, data acquisition system, computer monitoring system, transistor or microcomputer type relay protection system and telecontrol communication system to stabilize potential and prevent interference. Instrumented grounding is also known as grounding the electronic system.
27 Grounding Resistance - refers to the resistance encountered when current enters the earth through the grounding body and spreads to the surroundings.
28 Voltage - When the unit positive charge changes from high electric displacement to low potential, the electric field force is called voltage.
29 current - _ is a physical phenomenon in which a large amount of electric charge is regularly orientated under the action of an electric field force.
30 Resistance - When the current passes through the conductor, it is subject to resistance. Because the free electrons constantly collide with atoms and molecules in the conductor during motion, the free electrons are subjected to certain resistance. This resistance of the conductor to the current is called resistance.
31 The rated current of the motor - the maximum operating current of the motor in normal continuous operation.
32. The power factor of the motor - the ratio of rated active power to rated apparent power
33 The rated voltage of the motor - _ is the line voltage at the rated operating mode.
34. The rated power of the motor _——_ refers to the mechanical power that the shaft can output when operating under rated conditions.
35. The rated speed of the motor - the speed at which it is rated, rated frequency and rated load.
36 Power System Oscillation - Due to power plant lead-out line or line switch failure, tripping, etc., the instability of the power system caused by the instability of the power system caused by the abnormality of the frequency meter, the instability of the load meter and the voltmeter is called the power system. oscillation.
37 Protective earthing—The metal casing, frame, etc. of the electrical equipment are reliably connected to the earth through the grounding device; in the system where the power neutral point is not grounded, it is an important measure to protect personal safety.
38 Protection and zero connection - In the neutral point grounding system, connecting the metal casing, frame, etc. of the electrical equipment to the neutral point and connecting the neutral line is also an important measure to protect personal safety.
39 Busbars - Busbars act as a collection and distribution of electrical energy, also known as busbars. In principle it is an electrical node in the circuit that determines the number of power distribution equipment and shows how the generator, transformer, and wiring are connected, and how it is connected to the system to complete the transmission and distribution tasks.
40 short circuit - in the three-phase circuit, the phase and phase and the phase and the ground are connected by small impedance or direct connection, which causes the current in the circuit to increase sharply. This phenomenon is called short circuit.
41 line voltage - in the three-phase circuit, no matter which type of connection method has three phase lines, the voltage between the phase lines is called the line voltage.
42 automatic reclosing - a device that can automatically reclose without manual operation when the circuit fails and the circuit breaker trips
43 breakdown voltage - when the dielectric breakdown occurs, the voltage applied across the dielectric is called the breakdown voltage.
44 DC - the magnitude and direction of the voltage or current does not change with time, called DC
45 DC equipment - DC equipment refers to DC power supply units that supply DC operating power to relay protection and control circuits, as well as supply of accident lighting.
46 Short-circuit ratio—The ratio of the excitation current at the rated speed to the excitation current when the no-load voltage is the rated value and the excitation current when the three-phase symmetrical steady-state short-circuit current is the rated value.
47 induced electromotive force—the electromotive force generated in the circuit when the magnetic flux in the area surrounded by the conductive loop changes, or the electromotive force generated at both ends of the wire when the wire cuts the magnetic field line.
48 Generator Efficiency - The ratio of generator output power to drilling power expressed as a percentage. Do not
When specified, it refers to the value at rated working conditions.
49-axis current—The current flowing from the bearing, the housing, and the base of the base that is damaged by the oil film insulation from one end of the turbine generator shaft shaft caused by the shaft voltage, and the current flowing to the other end of the shaft.
50 generator auxiliary protection - the protection of the generator relay protection supplements the main protection, backup protection and abnormal operation protection performance. If the voltage sensor circuit may be disconnected, the circuit breaker may malfunction or flashover, the generator Accidents may occur during start-up, synchronization, and shutdown. These primary and backup protections cannot be detected. Therefore, additional auxiliary protection is added to the large units.
51 Generator Backup Protection - In the relay protection of the generator, when the main protection exits the operation or fails and refuses to move, it can still react to the fault and act on the relay protection of the circuit breaker and the automatic device. There are mainly composite current quick-break protection, impedance protection, and directional overcurrent protection for composite voltage starting.
52 strong excitation - when the synchronous generator's automatic voltage regulator measured the grid voltage is lower than a certain set value. Usually 80% to 85% of the rated value, that is, the output step signal. Controls the excitation system to quickly raise the excitation voltage to the top value. The use of relays to achieve forced excitation, commonly referred to as relay forced excitation.
53 Demagnetization - A measure to quickly disconnect the excitation power of the synchronous generator and quickly dissipate the magnetic field energy stored in the excitation winding. In order to reduce the damage caused by the internal fault current of the generator or the overvoltage during the disengagement, when the generator short circuit protection or the relay protection device protected by the abnormal operation of the generator trips the circuit breaker, it is required to simultaneously de-excitation.
54 exciter item value voltage multiple - the ratio of the maximum value of the DC voltage that the exciter of the synchronous generator can provide under rated speed and specified conditions to its rated excitation voltage.
55 excitation system voltage response ratio - the output voltage growth rate determined by the voltage response curve of the excitation system divided by the value of the rated excitation voltage is an important indicator to measure the dynamic performance of the excitation system. Excitation system nominal response
56 split transformer - a multi-winding power transformer consisting of one high voltage winding and two or more low voltage windings of the same voltage and capacity per phase. The normal power transfer of the split transformer is only between the high and low voltage windings. In the event of a fault, it has the effect of limiting the short-circuit current. Split-winding
57 isolating switch - a specified insulation distance and visible fracture between the contacts in the opening position. Switching device capable of cutting normal operating current and short-circuit current when in the closing position. When the operating current is small or the voltage between the two terminals of each pole of the isolating switch does not change significantly before and after the closing and breaking, the isolating switch has the ability to close and open the circuit, and has both operation and isolation functions.
58 non-excitation voltage regulator - the device that switches the coil tap in the winding to achieve voltage regulation under the condition that the transformer is not energized, also called the non-excitation tapping. The pressure regulating device has a simple structure, low cost, reliable parts, but a small pressure range. Only for occasions where constant pressure regulation is not required.
59 on-load voltage regulator - a device that regulates voltage when the transformer is not interrupted. Also known as on-load tap-changer. Voltage adjustment by means of on-load voltage regulator. It can stabilize the voltage of the power grid and improve the reliability and economy of the power supply.
60 primary equipment - primary equipment is equipment for direct production and transmission and distribution. Such as: generators, transformers, switch electrical, power cables, etc.
61 primary circuit - the electrical main wiring from the generator through the transformer and transmission and distribution lines to the electrical equipment, usually called the primary circuit.
62 Secondary equipment - Secondary equipment is auxiliary equipment for monitoring, measuring, operating control and protection of primary equipment, such as instruments, relays, control cables, control and signal equipment, etc.
63 secondary circuit - a circuit in which secondary equipment is connected in a certain order, called a secondary circuit or a secondary circuit.
64 Low Voltage Switch - is a switching device used to turn on or off AC and DC circuits below 1000 volts. Unlike the low voltage in the Safety Regulations (the voltage to ground is below 250 volts).
65 Contactor - is a low voltage switch used to switch the load current in the circuit from a long distance. It is widely used in circuits that frequently start and control the motor.
66 automatic air switch - automatic air switch for short automatic switch, is the most complete switch in the low-voltage switch. It can not only cut off the load current of the circuit, but also can cut off the short-circuit current. It is often used as the main control device in the low-voltage high-power circuit.
67 de-excitation switch - is a DC single-pole air automatic switch dedicated to the excitation circuit of the generator.
68 isolating switch - is a switch with a clearly visible fracture, no arc extinguishing device. It can be used to turn on and off lines with voltage and no load. It also allows to turn on or off unloaded lines, voltage transformers and no-load transformers with limited capacity. The main purpose of the isolating switch is to isolate the supply voltage when the electrical equipment is in service.
69 high voltage circuit breaker - also known as high voltage switch. It can not only cut off or close the no-load current and load current in the high-voltage circuit, but also cut off the short-circuit current through the action of the relay protection device when the system fails. It has a fairly complete arc extinguishing structure and sufficient current interrupting capability.
70 arc suppression coil - is a adjustable inductor with iron core, installed in the neutral point of the transformer or generator, when the single-phase ground fault occurs, to reduce the ground current and arc suppression.
71 Reactor - The reactor is an inductive coil with a small resistance. The coils are insulated from each other and the entire coil is insulated from the ground. The reactor is connected in series to limit the short circuit current in the circuit.
72 eddy current phenomenon - if the coil is placed on a monolithic core, the core can be seen as composed of a number of closed wires, and the plane formed by the closed wire is perpendicular to the direction of the magnetic flux. Each closed wire can be seen as a closed conductive loop. When the alternating current is passed through the coil, the magnetic flux passing through the closed wire is constantly changing, so that an induced electromotive force is generated in each of the wires and induces an induced current. Thus, in the entire core, an induced current flowing around the axis of the core is formed as if it were a vortex in the water. This induced current generated in the core is called eddy current.
73 Eddy Current Loss - As current flows through the resistor, the eddy current in the core consumes energy and heats the core. This energy loss is called eddy current loss.
74 small current grounding system - the neutral point is not grounded or grounded via the arc suppression coil.
75 large current grounding system - a system where the neutral point is directly grounded.
76 Armature reaction - When there is no armature current, the main magnetic field of the air gap is generated separately by the excitation current. When there is armature current, the main magnetic field of the air gap is superimposed by the magnetic field of the excitation current and the magnetic field of the armature current. . This effect of the armature current on the main magnetic field is called the armature reaction.
77 asynchronous motor - also known as induction motor, it works according to the principle that the conductor cuts the magnetic field line to generate the induced electromotive force, and the current carrying conductor receives the magnetic permeability in the magnetic field. In order to maintain the relative motion between the magnetic field and the rotor conductor, the rotational speed of the rotor is always smaller than the rotational speed of the rotating magnetic field, so it is called an asynchronous motor.
78 Synchronous speed——When a three-phase symmetrical current is applied to the three-phase symmetrical winding of the asynchronous motor, a rotating magnetic field is generated in the air gap of the motor. The rotational speed of the rotating magnetic field is different according to the number of poles of the motor, and the number of poles is different. The speed is slow. We call the rotational speed of this rotating magnetic field a synchronous speed.
79 slip rate - the difference between the synchronous speed n1 and the motor speed n (n1-n) is called the speed difference. The ratio of the speed difference to the synchronous speed is called the slip rate. The slip rate S is usually expressed as a percentage, ie S=( N1-n)/ n1╳100%
80 star - triangular switching start - If the motor is in normal operation, the stator windings are connected in a triangle, the stator windings are connected in a star shape at the start, and the triangle is run after the start. This starting method is called star-delta exchange. Start up.
81 absorption ratio - the ratio of the resistance of 60 seconds and 15 seconds after the DC voltage is applied to the insulation sample.
82 Working Grounding - In order to ensure safe and reliable operation of electrical equipment under normal or fault conditions, to prevent high voltage caused by equipment failure, it must be grounded at a certain point in the power system, called working ground.
83 Protective earthing - In order to prevent electrical shock caused by electrical insulation damage, the metal casing or frame of the electrical equipment that is normally uncharged is connected to the earth, which is called protective earthing.
84 protection and zero connection - in the power neutral point grounding system, the metal casing or frame of the electrical equipment is connected to the neutral line from the neutral point. This is also an important measure to protect personal safety.
85 Arc - A large collection of point sparks forms an arc.
86 phase sequence - the order in which the sinusoids of each phase pass the same value. Any set of asymmetric three-phase sinusoidal AC voltage or current phasors can be decomposed into three sets of symmetrical components: one set is a positive sequence component, represented by the subscript "1", and the phase sequence is phase sequenced with the original asymmetric sinusoidal quantity. Consistent, that is, the order of ABC, each phase is 120° out of phase; one set is a negative sequence component, which is represented by the subscript "2", and the phase sequence is opposite to the phase sequence of the original asymmetric sinusoid, that is, the order of ACB, each phase The phases are 120° out of phase; the other group is a zero-sequence component, which is represented by the subscript “0â€, and the phases of the three phases are the same. For example, the asymmetry of two-phase operation will result in negative sequence and zero sequence components.
87 relay starting current - the minimum current value that enables the relay to operate.
88 Current Relay - A relay that determines the operation of a relay coil current by its reaction is called a current relay.
89 voltage relay - a relay that determines the operation or not by the voltage of the reaction.
90 fast relays - generally refers to relays with relay action times less than 10 milliseconds.
91 quick-break protection - no time limit, as long as the current reaches the set value, it can be protected by instantaneous action.
92 Differential Protection - is the protection that is achieved by the change of current when the electrical equipment fails.
93 Zero-sequence protection - protection of the zero-sequence current and zero-sequence voltage electrical quantities that are unique to the power system ground fault.
94 Distance Protection - A type of protection that reflects the distance from the point of failure to the point at which the installation is protected.
95 Automatic reclosing - A device that can automatically reclose without manual operation when the circuit fails and the circuit breaker trips. The reclosing is divided into single phase and integrated reclosing.
96 integrated reclosing - its function is: single-phase fault single phase, unsuccessful three-phase jump; phase-to-phase fault three-phase, three-phase coincidence, unsuccessful three-phase jump.
97 Acceleration after reclosing - Reclosing on a permanent fault, the protection device again has no time limit action to open the circuit breaker and is not reclosing, called reclosing after acceleration.
98 Protection - It can meet the requirements of system stability and equipment safety, and selectively remove the protection of protected equipment and full line faults.
99 backup protection - protection against faults when the main protection does not work or the circuit breaker refuses to move
100 power factor - the ratio of active power P to apparent power S.
101 Switching Operation - When an electrical device transitions from one state to another, or changes the mode of operation of the system, a series of operations are required. We call this operation the switching operation of the electrical equipment. The main operations of the switch are:
(1) Power failure of the transformer
(2) Power line stop transmission
(3) Generator start, parallel and unwind operation
(4) Network loop and loop
(5) Change of busbar wiring mode (ie, reverse busbar operation)
(6) Neutral point grounding method change and arc suppression coil adjustment
(7) Changes in relay protection and automatic device use status
(8) Installation and removal of the grounding wire
102. No-load loss: the sinusoidal AC rated voltage of the rated frequency is applied to one coil of the transformer (at the rated tap position), and the remaining coils are open, the power drawn by the transformer is used to supply the transformer core. Loss (eddy current and hysteresis loss)
103. No-load current: When the transformer is running at no load, the main flux is established by the no-load current, so the no-load current is the excitation current. The rated no-load current is applied to a coil (at the rated tap position) with a positive weak AC rated voltage at the rated frequency, and the three-phase arithmetic average of the current drawn by the transformer when the remaining coils are open, at rated current The percentage is expressed.
104. Short-circuit loss: the power absorbed by the transformer when the rated current of the rated frequency passes through one coil of the transformer, and the other coil is short-circuited. It is the loss caused by the resistance of the transformer coil, that is, the copper loss (the coil is at the rated tap position, Temperature 70 ° C).
105. Short-circuit voltage: The voltage at the rated frequency (at the rated tap position) applied to generate a rated current in the other coil when one coil is short-circuited, expressed as a percentage of the rated voltage, which reflects the transformer impedance ( Resistance and leakage reactance) parameters, also known as impedance voltage (temperature 70 ° C).
1 Active power - the part of the energy used to convert into electromagnetic form during the process of transmitting and transmitting AC power is called active power.
2 Reactive power - the part of the energy used for the exchange of electromagnetic fields in the circuit during the process of transmitting and receiving AC power is called reactive power.
3 Power system - The whole system consisting of generators, power distribution units, boost and step-down substations, power lines and power users is called the power system. Neutral point displacement: In the case of a three-phase circuit, when the three-phase load of the power supply voltage is symmetrical, if the three-phase load is also symmetrical, the neutral point voltage is zero regardless of the presence or absence of a neutral point. However, if the three-phase load is asymmetrical and there is no neutral or neutral impedance, the voltage will appear at the neutral point. This phenomenon is called the neutral point displacement phenomenon.
4 operation overvoltage - transient voltage rise caused by circuit breaker switching operation and short circuit or ground fault, called operation over voltage;
5 Resonant overvoltage - due to the operation of the circuit breaker, the grid loop is divided or the core component tends to be saturated, causing the inductive reactance and capacitive reactance of a loop to meet the resonance condition, and the voltage rise that may cause resonance is called resonance. Voltage.
6 Electrical main wiring—mainly refers to a circuit designed to transmit electrical energy in a power plant, substation, and power system, designed to meet predetermined power transmission modes and operation requirements, indicating the interconnection relationship between high voltage electrical equipment. .
7 double busbar connections - it has two sets of busbars: working busbar I and spare busbar l. Each circuit is connected to two sets of busbars via a circuit breaker and two sets of isolating switches. The busbars are connected by busbar connection breakers (referred to as busbars), which are called double busbars.
8 One and a half circuit breaker wiring - each two components (outlet or power supply) is connected in series with three circuit breakers to two sets of busbars, called a half circuit breaker wiring, also known as 3/2 wiring.
9 plant power - in the process of starting, running, decommissioning and overhauling, there are a large number of mechanical equipment driven by electric motor to ensure the main equipment of the unit and coal, coal, ash, dust and water Handling the normal operation of auxiliary equipment. These electric motors and the electrical equipment for operation, operation, testing, overhaul, lighting, etc. of the whole plant belong to the factory load, and the total power consumption is collectively referred to as the factory power.
10 plant power consumption rate - the percentage of power consumption of the plant to the total power generation of the power plant is called the plant power consumption rate. The plant electricity rate is one of the main economic indicators for power plant operation.
11 Frequent load – the motor that is used continuously for continuous operation every day;
12 Infrequent load - load used only during maintenance, accidents or start and stop of the furnace; ''
13 continuous load - load for more than 2 hours per continuous operation;
14 short-time load - load only 10 - 120min at a time;
15 intermittent load - repeated cyclical work, which does not exceed 10 minutes of load per cycle.
16 Self-starting of the motor - the motor that runs normally in the factory system. "When the voltage of the power supply busbar suddenly disappears or drops significantly, it will drop a lot at the end of its speed after a short period of time (usually 0.5-1.5 s). Monk
Before the power is stopped, the bus voltage of the factory is restored to normal (such as power failure troubleshooting or automatic backup of the standby power supply), the motor will accelerate itself and return to normal operation. This process is called self-starting of the motor.
17 Loss of magnetism - sudden or partial loss of excitation of a synchronous generator is called loss of magnetism
18 Excitation Control System - The entire system consisting of the excitation regulator, the excitation power unit and the generator itself is called the excitation control system.
19 Self-excited static excitation system - using a transformer connected to the generator outlet. (called the excitation transformer ') as the excitation power supply, which is rectified by silicon and then supplied to the generator for excitation. Since the excitation transformer is connected in parallel to the generator outlet, this excitation mode is called self-excitation mode, and the excitation transformer and rectifier are all stationary components, so it is also called self-excited static excitation system.
20 transformers - sensors that obtain electrical primary loop information from secondary equipment such as measuring instruments, relay protection and automatic devices in the power system. The function of the transformer is to convert high voltage and large current into low voltage and small current.
21 SF6 circuit breaker - a circuit breaker using SFe gas with excellent arc extinguishing performance and insulation properties as an arc extinguishing medium, called SF 6 circuit breaker. It has the characteristics of strong breaking capacity and small volume, but the structure is more complicated, and the metal consumption is large and the price is relatively expensive.
22 Vacuum Circuit Breaker - A circuit breaker that uses a high dielectric strength of vacuum to extinguish an arc, called a vacuum circuit breaker. The circuit breaker has the characteristics of fast arc extinguishing speed, non-oxidation of the contact material, long service life and small volume.
23 working grounding - is to ensure the grounding required for the normal operation of the power system. For example, the neutral point of the transformer in the neutral point direct grounding system is used to stabilize the grid to ground potential, thereby reducing the insulation to ground.
24 lightning protection grounding - is the grounding set for the needs of lightning protection. For example, lightning rod (wire), lightning arrester grounding, the purpose is to make lightning current smoothly into the earth, in order to help reduce the lightning overvoltage, it is also known as overvoltage protection grounding.
25 Protective earthing - also known as safety grounding, is the grounding for personal safety, that is, the outer casing of the electrical equipment (including the cable skin) must be grounded to prevent the electrical insulation of the outer casing from endangering personal safety.
26 Instrument Control Grounding—The grounding of the power control system, data acquisition system, computer monitoring system, transistor or microcomputer type relay protection system and telecontrol communication system to stabilize potential and prevent interference. Instrumented grounding is also known as grounding the electronic system.
27 Grounding Resistance - refers to the resistance encountered when current enters the earth through the grounding body and spreads to the surroundings.
28 Voltage - When the unit positive charge changes from high electric displacement to low potential, the electric field force is called voltage.
29 current - _ is a physical phenomenon in which a large amount of electric charge is regularly orientated under the action of an electric field force.
30 Resistance - When the current passes through the conductor, it is subject to resistance. Because the free electrons constantly collide with atoms and molecules in the conductor during motion, the free electrons are subjected to certain resistance. This resistance of the conductor to the current is called resistance.
31 The rated current of the motor - the maximum operating current of the motor in normal continuous operation.
32. The power factor of the motor - the ratio of rated active power to rated apparent power
33 The rated voltage of the motor - _ is the line voltage at the rated operating mode.
34. The rated power of the motor _——_ refers to the mechanical power that the shaft can output when operating under rated conditions.
35. The rated speed of the motor - the speed at which it is rated, rated frequency and rated load.
36 Power System Oscillation - Due to power plant lead-out line or line switch failure, tripping, etc., the instability of the power system caused by the instability of the power system caused by the abnormality of the frequency meter, the instability of the load meter and the voltmeter is called the power system. oscillation.
37 Protective earthing—The metal casing, frame, etc. of the electrical equipment are reliably connected to the earth through the grounding device; in the system where the power neutral point is not grounded, it is an important measure to protect personal safety.
38 Protection and zero connection - In the neutral point grounding system, connecting the metal casing, frame, etc. of the electrical equipment to the neutral point and connecting the neutral line is also an important measure to protect personal safety.
39 Busbars - Busbars act as a collection and distribution of electrical energy, also known as busbars. In principle it is an electrical node in the circuit that determines the number of power distribution equipment and shows how the generator, transformer, and wiring are connected, and how it is connected to the system to complete the transmission and distribution tasks.
40 short circuit - in the three-phase circuit, the phase and phase and the phase and the ground are connected by small impedance or direct connection, which causes the current in the circuit to increase sharply. This phenomenon is called short circuit.
41 line voltage - in the three-phase circuit, no matter which type of connection method has three phase lines, the voltage between the phase lines is called the line voltage.
42 automatic reclosing - a device that can automatically reclose without manual operation when the circuit fails and the circuit breaker trips
43 breakdown voltage - when the dielectric breakdown occurs, the voltage applied across the dielectric is called the breakdown voltage.
44 DC - the magnitude and direction of the voltage or current does not change with time, called DC
45 DC equipment - DC equipment refers to DC power supply units that supply DC operating power to relay protection and control circuits, as well as supply of accident lighting.
46 Short-circuit ratio—The ratio of the excitation current at the rated speed to the excitation current when the no-load voltage is the rated value and the excitation current when the three-phase symmetrical steady-state short-circuit current is the rated value.
47 induced electromotive force—the electromotive force generated in the circuit when the magnetic flux in the area surrounded by the conductive loop changes, or the electromotive force generated at both ends of the wire when the wire cuts the magnetic field line.
48 Generator Efficiency - The ratio of generator output power to drilling power expressed as a percentage. Do not
When specified, it refers to the value at rated working conditions.
49-axis current—The current flowing from the bearing, the housing, and the base of the base that is damaged by the oil film insulation from one end of the turbine generator shaft shaft caused by the shaft voltage, and the current flowing to the other end of the shaft.
50 generator auxiliary protection - the protection of the generator relay protection supplements the main protection, backup protection and abnormal operation protection performance. If the voltage sensor circuit may be disconnected, the circuit breaker may malfunction or flashover, the generator Accidents may occur during start-up, synchronization, and shutdown. These primary and backup protections cannot be detected. Therefore, additional auxiliary protection is added to the large units.
51 Generator Backup Protection - In the relay protection of the generator, when the main protection exits the operation or fails and refuses to move, it can still react to the fault and act on the relay protection of the circuit breaker and the automatic device. There are mainly composite current quick-break protection, impedance protection, and directional overcurrent protection for composite voltage starting.
52 strong excitation - when the synchronous generator's automatic voltage regulator measured the grid voltage is lower than a certain set value. Usually 80% to 85% of the rated value, that is, the output step signal. Controls the excitation system to quickly raise the excitation voltage to the top value. The use of relays to achieve forced excitation, commonly referred to as relay forced excitation.
53 Demagnetization - A measure to quickly disconnect the excitation power of the synchronous generator and quickly dissipate the magnetic field energy stored in the excitation winding. In order to reduce the damage caused by the internal fault current of the generator or the overvoltage during the disengagement, when the generator short circuit protection or the relay protection device protected by the abnormal operation of the generator trips the circuit breaker, it is required to simultaneously de-excitation.
54 exciter item value voltage multiple - the ratio of the maximum value of the DC voltage that the exciter of the synchronous generator can provide under rated speed and specified conditions to its rated excitation voltage.
55 excitation system voltage response ratio - the output voltage growth rate determined by the voltage response curve of the excitation system divided by the value of the rated excitation voltage is an important indicator to measure the dynamic performance of the excitation system. Excitation system nominal response
56 split transformer - a multi-winding power transformer consisting of one high voltage winding and two or more low voltage windings of the same voltage and capacity per phase. The normal power transfer of the split transformer is only between the high and low voltage windings. In the event of a fault, it has the effect of limiting the short-circuit current. Split-winding
57 isolating switch - a specified insulation distance and visible fracture between the contacts in the opening position. Switching device capable of cutting normal operating current and short-circuit current when in the closing position. When the operating current is small or the voltage between the two terminals of each pole of the isolating switch does not change significantly before and after the closing and breaking, the isolating switch has the ability to close and open the circuit, and has both operation and isolation functions.
58 non-excitation voltage regulator - the device that switches the coil tap in the winding to achieve voltage regulation under the condition that the transformer is not energized, also called the non-excitation tapping. The pressure regulating device has a simple structure, low cost, reliable parts, but a small pressure range. Only for occasions where constant pressure regulation is not required.
59 on-load voltage regulator - a device that regulates voltage when the transformer is not interrupted. Also known as on-load tap-changer. Voltage adjustment by means of on-load voltage regulator. It can stabilize the voltage of the power grid and improve the reliability and economy of the power supply.
60 primary equipment - primary equipment is equipment for direct production and transmission and distribution. Such as: generators, transformers, switch electrical, power cables, etc.
61 primary circuit - the electrical main wiring from the generator through the transformer and transmission and distribution lines to the electrical equipment, usually called the primary circuit.
62 Secondary equipment - Secondary equipment is auxiliary equipment for monitoring, measuring, operating control and protection of primary equipment, such as instruments, relays, control cables, control and signal equipment, etc.
63 secondary circuit - a circuit in which secondary equipment is connected in a certain order, called a secondary circuit or a secondary circuit.
64 Low Voltage Switch - is a switching device used to turn on or off AC and DC circuits below 1000 volts. Unlike the low voltage in the Safety Regulations (the voltage to ground is below 250 volts).
65 Contactor - is a low voltage switch used to switch the load current in the circuit from a long distance. It is widely used in circuits that frequently start and control the motor.
66 automatic air switch - automatic air switch for short automatic switch, is the most complete switch in the low-voltage switch. It can not only cut off the load current of the circuit, but also can cut off the short-circuit current. It is often used as the main control device in the low-voltage high-power circuit.
67 de-excitation switch - is a DC single-pole air automatic switch dedicated to the excitation circuit of the generator.
68 isolating switch - is a switch with a clearly visible fracture, no arc extinguishing device. It can be used to turn on and off lines with voltage and no load. It also allows to turn on or off unloaded lines, voltage transformers and no-load transformers with limited capacity. The main purpose of the isolating switch is to isolate the supply voltage when the electrical equipment is in service.
69 high voltage circuit breaker - also known as high voltage switch. It can not only cut off or close the no-load current and load current in the high-voltage circuit, but also cut off the short-circuit current through the action of the relay protection device when the system fails. It has a fairly complete arc extinguishing structure and sufficient current interrupting capability.
70 arc suppression coil - is a adjustable inductor with iron core, installed in the neutral point of the transformer or generator, when the single-phase ground fault occurs, to reduce the ground current and arc suppression.
71 Reactor - The reactor is an inductive coil with a small resistance. The coils are insulated from each other and the entire coil is insulated from the ground. The reactor is connected in series to limit the short circuit current in the circuit.
72 eddy current phenomenon - if the coil is placed on a monolithic core, the core can be seen as composed of a number of closed wires, and the plane formed by the closed wire is perpendicular to the direction of the magnetic flux. Each closed wire can be seen as a closed conductive loop. When the alternating current is passed through the coil, the magnetic flux passing through the closed wire is constantly changing, so that an induced electromotive force is generated in each of the wires and induces an induced current. Thus, in the entire core, an induced current flowing around the axis of the core is formed as if it were a vortex in the water. This induced current generated in the core is called eddy current.
73 Eddy Current Loss - As current flows through the resistor, the eddy current in the core consumes energy and heats the core. This energy loss is called eddy current loss.
74 small current grounding system - the neutral point is not grounded or grounded via the arc suppression coil.
75 large current grounding system - a system where the neutral point is directly grounded.
76 Armature reaction - When there is no armature current, the main magnetic field of the air gap is generated separately by the excitation current. When there is armature current, the main magnetic field of the air gap is superimposed by the magnetic field of the excitation current and the magnetic field of the armature current. . This effect of the armature current on the main magnetic field is called the armature reaction.
77 asynchronous motor - also known as induction motor, it works according to the principle that the conductor cuts the magnetic field line to generate the induced electromotive force, and the current carrying conductor receives the magnetic permeability in the magnetic field. In order to maintain the relative motion between the magnetic field and the rotor conductor, the rotational speed of the rotor is always smaller than the rotational speed of the rotating magnetic field, so it is called an asynchronous motor.
78 Synchronous speed——When a three-phase symmetrical current is applied to the three-phase symmetrical winding of the asynchronous motor, a rotating magnetic field is generated in the air gap of the motor. The rotational speed of the rotating magnetic field is different according to the number of poles of the motor, and the number of poles is different. The speed is slow. We call the rotational speed of this rotating magnetic field a synchronous speed.
79 slip rate - the difference between the synchronous speed n1 and the motor speed n (n1-n) is called the speed difference. The ratio of the speed difference to the synchronous speed is called the slip rate. The slip rate S is usually expressed as a percentage, ie S=( N1-n)/ n1╳100%
80 star - triangular switching start - If the motor is in normal operation, the stator windings are connected in a triangle, the stator windings are connected in a star shape at the start, and the triangle is run after the start. This starting method is called star-delta exchange. Start up.
81 absorption ratio - the ratio of the resistance of 60 seconds and 15 seconds after the DC voltage is applied to the insulation sample.
82 Working Grounding - In order to ensure safe and reliable operation of electrical equipment under normal or fault conditions, to prevent high voltage caused by equipment failure, it must be grounded at a certain point in the power system, called working ground.
83 Protective earthing - In order to prevent electrical shock caused by electrical insulation damage, the metal casing or frame of the electrical equipment that is normally uncharged is connected to the earth, which is called protective earthing.
84 protection and zero connection - in the power neutral point grounding system, the metal casing or frame of the electrical equipment is connected to the neutral line from the neutral point. This is also an important measure to protect personal safety.
85 Arc - A large collection of point sparks forms an arc.
86 phase sequence - the order in which the sinusoids of each phase pass the same value. Any set of asymmetric three-phase sinusoidal AC voltage or current phasors can be decomposed into three sets of symmetrical components: one set is a positive sequence component, represented by the subscript "1", and the phase sequence is phase sequenced with the original asymmetric sinusoidal quantity. Consistent, that is, the order of ABC, each phase is 120° out of phase; one set is a negative sequence component, which is represented by the subscript "2", and the phase sequence is opposite to the phase sequence of the original asymmetric sinusoid, that is, the order of ACB, each phase The phases are 120° out of phase; the other group is a zero-sequence component, which is represented by the subscript “0â€, and the phases of the three phases are the same. For example, the asymmetry of two-phase operation will result in negative sequence and zero sequence components.
87 relay starting current - the minimum current value that enables the relay to operate.
88 Current Relay - A relay that determines the operation of a relay coil current by its reaction is called a current relay.
89 voltage relay - a relay that determines the operation or not by the voltage of the reaction.
90 fast relays - generally refers to relays with relay action times less than 10 milliseconds.
91 quick-break protection - no time limit, as long as the current reaches the set value, it can be protected by instantaneous action.
92 Differential Protection - is the protection that is achieved by the change of current when the electrical equipment fails.
93 Zero-sequence protection - protection of the zero-sequence current and zero-sequence voltage electrical quantities that are unique to the power system ground fault.
94 Distance Protection - A type of protection that reflects the distance from the point of failure to the point at which the installation is protected.
95 Automatic reclosing - A device that can automatically reclose without manual operation when the circuit fails and the circuit breaker trips. The reclosing is divided into single phase and integrated reclosing.
96 integrated reclosing - its function is: single-phase fault single phase, unsuccessful three-phase jump; phase-to-phase fault three-phase, three-phase coincidence, unsuccessful three-phase jump.
97 Acceleration after reclosing - Reclosing on a permanent fault, the protection device again has no time limit action to open the circuit breaker and is not reclosing, called reclosing after acceleration.
98 Protection - It can meet the requirements of system stability and equipment safety, and selectively remove the protection of protected equipment and full line faults.
99 backup protection - protection against faults when the main protection does not work or the circuit breaker refuses to move
100 power factor - the ratio of active power P to apparent power S.
101 Switching Operation - When an electrical device transitions from one state to another, or changes the mode of operation of the system, a series of operations are required. We call this operation the switching operation of the electrical equipment. The main operations of the switch are:
(1) Power failure of the transformer
(2) Power line stop transmission
(3) Generator start, parallel and unwind operation
(4) Network loop and loop
(5) Change of busbar wiring mode (ie, reverse busbar operation)
(6) Neutral point grounding method change and arc suppression coil adjustment
(7) Changes in relay protection and automatic device use status
(8) Installation and removal of the grounding wire
102. No-load loss: the sinusoidal AC rated voltage of the rated frequency is applied to one coil of the transformer (at the rated tap position), and the remaining coils are open, the power drawn by the transformer is used to supply the transformer core. Loss (eddy current and hysteresis loss)
103. No-load current: When the transformer is running at no load, the main flux is established by the no-load current, so the no-load current is the excitation current. The rated no-load current is applied to a coil (at the rated tap position) with a positive weak AC rated voltage at the rated frequency, and the three-phase arithmetic average of the current drawn by the transformer when the remaining coils are open, at rated current The percentage is expressed.
104. Short-circuit loss: the power absorbed by the transformer when the rated current of the rated frequency passes through one coil of the transformer, and the other coil is short-circuited. It is the loss caused by the resistance of the transformer coil, that is, the copper loss (the coil is at the rated tap position, Temperature 70 ° C).
105. Short-circuit voltage: The voltage at the rated frequency (at the rated tap position) applied to generate a rated current in the other coil when one coil is short-circuited, expressed as a percentage of the rated voltage, which reflects the transformer impedance ( Resistance and leakage reactance) parameters, also known as impedance voltage (temperature 70 ° C).
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