Wiring diagram and operating specifications for dual power switch
Dual power supply is mainly divided into PC level dual power supply (integral type) and CB level dual power supply (dual circuit breaker type)
PC level dual power supply: a dual power supply that can be connected, carried, but not used for breaking short-circuit currents
If a load switch without an overcurrent release is selected as the actuator for a dual power supply, it belongs to a PC level automatic transfer switch. It does not have a protective function, but it has a high tolerance and connection ability, which can ensure the safety of the switch itself and not be damaged due to overload or short circuit faults, ensuring reliable connection of the circuit in this situation.
CB level dual power supply: a dual power supply equipped with an overcurrent release, whose main contact can be connected and used to break short-circuit current
If a circuit breaker with an overcurrent release is selected as the actuator for a dual power supply, it belongs to the CB level automatic transfer switch. Equipped with selective protection function, it can provide short circuit and overload protection for the load and cable at the lower end; Its ability to make and break is much greater than using other components such as contactors and relays.
1. When there is a power outage due to unforeseen circumstances and power cannot be restored in a short period of time, a backup power source must be activated. Steps:
① Cut off all circuit breakers for the mains power supply (including each circuit breaker in the control cabinet of the distribution room, and the mains power supply breaker in the dual power switching box), open the dual input anti backflow switch to the side of the self supply power supply, and keep the self supply circuit breaker in the dual power switching box in the disconnected state.
② Start the standby power supply (diesel generator set), and when the standby group is running normally, sequentially close the generator air switch and all circuit breakers in the control cabinet of the standby power supply.
③ Close each backup power circuit breaker inside the power switch box one by one, and send power to each load. ④ During the operation of the standby power supply, the operator on duty shall not leave the generator set and adjust the voltage, plant frequency, etc. in a timely manner according to changes in load. Any abnormalities found shall be dealt with in a timely manner.
2. When the mains power is restored, the power conversion work should be done in a timely manner, the backup power supply should be cut off, and the mains power supply should be restored.
Steps:
① Disconnect each circuit breaker of the self-contained power supply one by one in order: dual power switch box self-contained power supply circuit breaker → each circuit breaker of the self-contained power distribution cabinet → generator main switch → turn the dual switch to the side of the mains power supply.
② Stop the engine according to the diesel engine shutdown steps.
③ In order, close each circuit breaker one by one from the main switch of the mains power supply to each branch switch, and place the dual power switch box from the mains power supply circuit breaker in the closed position.
3. Check if all instruments and indicator lights are functioning properly, and start the cooling fan inside the transformer.
