Installation of power capacitor

The environmental requirements for the installation of compensation capacitor are as follows:

1) The capacitor shall be installed in a place without corrosive gas, steam, violent vibration, impact, explosion, flammability and other hazards. The fire rating of capacitor shall not be lower than grade II.

2) Capacitors installed outdoors shall be protected from direct sunlight.

3) The ambient temperature of the capacitor room shall meet the requirements of the manufacturer, generally 40 ℃.

4) When a ventilator is installed in the capacitor room, the air outlet shall be installed at the upper end of the capacitor bank. The inlet and exhaust fans should be installed at the diagonal position.

5) Natural lighting and artificial lighting can be used in the capacitor room without heating device.

6) The door of high voltage capacitor room shall be opened outwards.

The technical requirements for capacitor installation are as follows:

1) In order to save the installation area, the high-voltage capacitor can be installed on the iron frame layer by layer, but the number of vertical layers should not be more than three, and the horizontal interlayer partition should not be installed between layers to ensure good heat dissipation. The installation position of the upper, middle and lower capacitors should be consistent, and the name plate should be outward.

2) The iron frame for installing high voltage capacitor shall be arranged in one or two rows. There shall be a walk for inspection between the rows, and the width of the walk shall not be less than 1.5m

3) The iron frame of high-voltage capacitor bank must be set with wire mesh, and the mesh hole of the mesh should be 3-4cm2.

4) Generally, the distance between high voltage capacitor shells shall not be less than 10 cm; the distance between low voltage capacitor shells shall not be less than 50 mm.

5) In the high voltage capacitor room, the clear distance between the upper and lower layers shall not be less than 0.2m; the distance between the bottom of the lower layer capacitor and the ground shall not be less than 0.3m.

6) The connection between each capacitor and the bus should adopt a separate flexible wire, not a hard bus connection, so as to avoid stress on the porcelain bushing during installation or operation, causing oil leakage or damage.

7) During installation, the contact surface between electrical circuit and grounding part should be good. Because any bad contact in the capacitor circuit may produce high-frequency oscillation arc, which will increase the working electric field strength and heat damage of the capacitor.

8) When the capacitor with lower voltage level operates in series in the network with higher voltage level, the measures such as installing insulator with equivalent operation voltage level between the shell of each capacitor and the ground should be taken to make it reliably insulated.

9) After the capacitor is star connected, it is used for the higher rated voltage. When the neutral point is not grounded, the shell of the capacitor shall be insulated from the ground.

10) Before the capacitor is installed, the primary capacitance should be distributed to make the phase to phase balance, and the deviation should not exceed 5% of the total capacity. When the relay protection device is installed, it should also meet the requirement that the balance current error does not exceed the relay protection action current.

11) The wiring of individual compensation capacitors shall be as follows: for the induction motor directly started or started by rheostat, the capacitor to improve the power factor can be directly connected with the outlet terminal of the motor, and no switchgear or fuse shall be installed between the two; for the induction motor started by star delta starter, it is better to use three single-phase capacitors, each with a capacitor The capacitor is directly connected in parallel with two terminals of each phase winding, so that the connection of capacitor is always consistent with the connection of winding.

12) For the group compensation low-voltage capacitor, it should be connected to the outside of the low-voltage group bus power switch to prevent the self excitation phenomenon when the group bus switch is disconnected.

13) The low-voltage capacitor bank with centralized compensation shall be equipped with special switch and installed outside the main switch of the line, not installed on the low-voltage bus.