Wiring schematic diagram of a factory's secondary low-voltage power distribution panel

Shown is the wiring schematic diagram of the BSL type low voltage distribution panel . It includes three parts, namely voltage measurement circuit, secondary relay protection circuit and electric energy measurement circuit.     (1) The voltage measurement circuit uses a voltage conversion switch SA and a voltmeter PV. Monitor the normal operation status of the three-phase power supply at any time to meet the voltage requirements required by the load.     (2) The secondary relay protection circuit is composed of a normally open contact, a red light HLt for the closing indication signal, a green light HLG for the opening indication signal, and a current-limiting resistor R. The line passes the closing and opening signals to ensure correct and clear circuit working status. When electrical equipment and lines are in operation, when overload or voltage loss occurs, the power loss release composed of the voltage loss release coil FV and the load switch QF will cut off the line in time to ensure safety of the line, equipment and people. base.     (3) Electric energy measurement circuit The electric energy measurement circuit includes a three-phase active energy meter PJ, three current transformers TA1-TA3 and three ammeters PA. Utilize the power consumption of the electric energy metering system, use current transformers and ammeters to form a current measurement line, and use L to monitor whether the line current is normal or not.