High-voltage switchgear (also known as complete switchgear or complete set of power distribution devices): electrical equipment mainly based on circuit breakers; refers to the manufacturer, according to the requirements of the primary electrical wiring diagram, the relevant high and low voltage electrical appliances (including control appliances, Protective appliances, measuring appliances) and busbars, current-carrying conductors, insulators, etc. are assembled in closed or open metal noble bodies as devices for receiving and distributing electrical energy in power systems.
一、High-voltage switchgear normal use conditions
1、ambient temperature：
The upper limit of ambient air does not exceed 40°C; the lower limit is -5°C in general areas and -15°C in severe cold areas. If the ambient temperature is too high, the electrical conductivity of the metal will decrease, the resistance will increase, and the surface oxidation will be intensified; in addition, the excessively high temperature will also greatly shorten the life of the insulating parts in the cabinet and reduce the insulating strength. On the contrary, if the ambient temperature is too low, internal stress will be generated in the insulating parts, which will eventually lead to the destruction of the insulating parts.
2、Altitude: generally not more than 1000 meters.
3、Environmental humidity: the daily average is not more than 95%, the monthly average is not more than 90%
4、Earthquake intensity: no more than 8 degrees
5、Other conditions: no fire, explosion hazard, serious pollution, chemical corrosion and severe vibration places
二、Composition of high voltage switchgear
三、Electrical components in high voltage switchgear
Primary electrical components (main circuit equipment)
Current transformer: CT such as LZZBJ9-10
Voltage transformer: PT such as JDZJ-10
Grounding switch: such as JN15-2
Lightning arrester (resistor-capacitor receiver)
Isolation switch: such as GN19-12, GN30-12, GN25-12
High voltage circuit breaker: such as less oil type (S), vacuum type (Z), SF6 type (L)
High voltage contactor: such as JCZ3-10D/400A type
High voltage fuse: such as RN2-12, XRNP-12
Transformer: such as SC(L) series dry transformer, S series oil transformer
High voltage live display: such as GSN-10Q type
Insulation parts: such as wall bushings, contact boxes, insulators, insulating heat shrink (cold shrink) sheaths
Main bus and branch bus
High voltage reactor: such as series type CKSC and starter motor type: QKSG
Load switch: such as FN26-12(L), FN16-12(Z)
High-voltage single-phase parallel capacitors: such as BFF12-30-1, etc.
Secondary components (secondary equipment or auxiliary equipment, refers to the low-voltage equipment that monitors, controls, measures, adjusts and protects primary equipment), the common equipment is as follows:
1. Relay 2. Electricity meter 3. Ammeter
4.Voltmeter 5. Power meter 6. Power factor meter
7.Frequency meter 8. Fuse 9. Air switch
10.Transfer switch 11. Signal light 12. Resistor
13.Button 14. Microcomputer comprehensive protection device, etc.
High voltage vacuum circuit breaker - left side view of switch cabinet
Busbar room Breaker room Cable room Relay room
The busbar compartment includes:
1. Busbar bushing: support, fix the busbar, and insulate the busbar from the cabinet;
2. Main bus: collecting and distributing electric energy;
3. Branch busbar: the branch drawn from the main busbar to the static contact of the upper port of the circuit breaker;
4. Static contact box: support and fix the upper static contact of the circuit breaker, and insulate the upper static contact from the cabinet.
Cable compartment includes
Current transformer: measure the current value of the outgoing line, and provide current signals for the ammeter, metering device, protection device, etc.; outgoing high-voltage cable: the outgoing line is connected to the electrical load through the high-voltage cable
pay attention!
When the equipment needs to be overhauled and the switch cabinet needs to be transferred to the overhaul state, a three-phase ground wire should be used to hang it on the outgoing copper bar. The high-voltage electroscope test is clear that there is no voltage.
handcart room：
1.Handcart track: Provide guidance and positioning for handcart when moving in the cabinet
2.Static contact partition: During the movement of the handcart in the test position and the working position, the shutters of the upper and lower static contact boxes are blocked, and they are automatically opened or closed accordingly, forming an effective isolation between the compartments.
Handcart circuit breaker body：
1.Handcart chassis: support the circuit breaker body, make the circuit breaker move in the test/working position, and cooperate with the maintenance trolley to pull the circuit breaker out of the handcart room;
2.Handcart chassis lock ring: lock the handcart chassis in the handcart;
3.Handcart mobile rocker and mobile operation socket: used for the mobile operation of the circuit breaker in the two positions of test and work. After inserting the mobile rocker, the circuit breaker is pushed in clockwise, and the circuit breaker is rolled out counterclockwise;
4.Operation panel of the circuit breaker body: indication of the opening and closing state of the body (the mechanical indication of the opening and closing state of the body is the most accurate sign for judging the opening and closing state of the circuit breaker);
5.Manual opening and closing button: as long as the circuit breaker has stored energy, the opening and closing operation can be performed through this button;
6.Indication of the state of energy storage on the body: mechanical indication of energy storage and non-energy storage;
7.Manual energy storage: when the automatic energy storage circuit cannot operate, the manual energy storage rod can be inserted to perform manual energy storage;
8.Circuit breaker closing times indication: Displays the number of times the circuit breaker is closed.
9.Secondary plug-in: the connection hub between the status of the circuit breaker body and the relay instrument room. If it cannot be inserted, the opening and closing status of the circuit breaker cannot be reflected on the control panel of the relay instrument room and the centralized control DCS, and the control panel and the control panel of the relay instrument room cannot be used. The centralized control DCS performs opening and closing operations on the circuit breaker;
10.Three-phase arc extinguishing column and upper and lower movable contacts: make and break the main part of the primary circuit.
Comprehensive protection device
The integrated protection measurement and control device integrates its protection function, automatic device and remote control function in one device. This device is the so-called "four-in-one" protection (protection, telemetry, remote control, remote signaling).
Appearance of the device
Dialogue interface (liquid crystal display): cyclically display device information, protect analog quantities, and measure the measured values of analog quantities;
Signal lights indicate the status: running, communication, action, alarm, close position, quantile position.
Running: When the device is in normal operation, the light flashes; if the light is on or off, it means that the device has stopped running and cannot work normally.
Communication: When the CAN communication of the device is normal, the light will be on for a long time, and if it is off, it means that the communication device has stopped.
Action: After the protection of the device is activated, the action information will be displayed on the LCD screen, and the action signal light will be always on. After the circuit breaker is tripped by the protection action, it is necessary to eliminate the fault. Press the "Reset" button to reset the action signal before the circuit breaker can be closed again, otherwise the circuit breaker closing circuit can not be operated and controlled;
Alarm: device protection alarm signal indicator;
Quantity: device trip circuit monitoring signal indicator;
Closed position: device trip circuit monitoring signal indicator light;
Reset: used to reset the "action, alarm" lights and protection action signals;
