High voltage switchgear (also called complete switchgear or complete power distribution device): electrical equipment mainly consisting of circuit breakers; It refers to that the manufacturer assembles relevant high and low voltage electrical appliances (including control appliances, protection appliances, measuring appliances), buses, current carrying conductors, insulators, etc. into closed or open metal noble bodies according to the requirements of the electrical primary main wiring diagram as the devices for receiving and distributing electric energy in the power system.
1、 Normal service conditions of high-voltage switchgear
1. Ambient temperature:
The upper limit of ambient air shall not exceed 40 ℃; The lower limit is - 5 ℃ in general areas and - 15 ℃ in severe cold areas. If the ambient temperature is too high, the conductivity of the metal will decrease, the resistance will increase, and the surface oxidation will intensify; In addition, excessive temperature will greatly shorten the life of insulating parts in the cabinet and reduce the insulation 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 damage of the insulating parts.
2. Altitude: generally no more than 1000m.
3. Ambient humidity: daily average value is not more than 95%, and monthly average value is not more than 90%
4. Seismic intensity: no more than 8 degrees
5. Other conditions: no fire, explosion, serious pollution, chemical corrosion and severe vibration
2、 Composition of high-voltage switchgear
3、 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
Arrester (R&C receiver)
Disconnector: such as GN19-12, GN30-12, GN25-12
High voltage circuit breaker: such as oil less type (S), vacuum type (Z), SF6 type (L)
High voltage contactor: such as JCZ3-10D/400A
High voltage fuse: such as RN2-12, XRNP-12
Transformer: such as SC (L) series dry transformer and S series oil transformer
High voltage live display: such as GSN-10Q
Insulating parts: such as wall bushing, contact box, insulator, insulation heat shrinkable (cold shrinkable) sheath
Main bus and branch bus
High voltage reactor: such as series CKSC and starter motor: QKSG
Load switch: e.g. FN26-12 (L), FN16-12 (Z)
High voltage single-phase shunt capacitor: such as BFF12-30-1, etc.
Secondary elements (secondary equipment or auxiliary equipment refers to low-voltage equipment that monitors, controls, measures, adjusts and protects the primary equipment), and common equipment are as follows:
1. Relay 2. Energy 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 lamp 12. Resistance
13. Button 14. Special attention to microcomputer integrated protection device!
When the equipment needs to be overhauled and the switch cabinet needs to be turned to the overhauling state, three-phase grounding wires should be hung on the outgoing copper bar. Before hanging the grounding wires, attention should be paid to checking and confirming the cabinet door behind the equipment switch to avoid entering the charged interval by mistake, and high-voltage electroscope should be used to verify that there is no voltage. Handcart room:
1. Handcart track: provide guidance and positioning for the handcart when moving in the cabinet
2. Static contact diaphragm: during the movement of the handcart at the test position and working position, the valves of the upper and lower static contact boxes are shielded, and automatically open or close accordingly to form an effective isolation between compartments.
Truck type circuit breaker body:
1. Handcart chassis: support the circuit breaker body to move the circuit breaker in the test/working position, and cooperate with the maintenance trolley to pull the circuit breaker out of the handcart chamber;
2. Handcart chassis lock ring: lock the handcart chassis in the handcart;
3. Trolley movable rocker and movable operation socket: used for the movable operation of the circuit breaker in the test/working positions. After inserting the movable rocker, the circuit breaker is pushed forward clockwise and pulled out anticlockwise;
4. Circuit breaker body operation panel: opening and closing status indication of the body (mechanical indication of opening and closing status of the body is the most accurate identification for judging the opening and closing status of the circuit breaker);
5. Manual opening/closing button: as long as the circuit breaker has stored energy, this button can be used for opening/closing operation;
6. Indication of energy storage status of the body: mechanical indication of stored energy and non stored energy;
7. Manual energy accumulator: when the automatic energy storage circuit cannot operate, the manual energy storage rod can be inserted for manual energy storage;
8. Circuit breaker closing times indication: display the closing times of the circuit breaker.
9. Secondary plug-in: the connection hub between the circuit breaker body status and the relay instrument room. If it cannot be plugged in, 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 opening and closing operation of the circuit breaker cannot be performed using the control panel of the relay instrument room and the centralized control DCS;
10. Three phase arc extinguishing column and upper and lower movable contacts: connect and disconnect the main part of the primary circuit.
