GREE Photovoltaic Direct-driven Inverter Multi VRF Units
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5 DC circuit breaker of the output bus terminal should be able to disconnect promptly and reliably.
6 Lightning arrester of the combining box should be effective.
3.5.3 AC Power Distribution Cabinet
Before checking on the AC power distribution cabinet, please inform relevant staff of the start and
end time of power cut and prepare all necessary tools.
Please pay attention to the following matters when checking on the AC power distribution cabinet:
1) After disconnecting power supply, check if the power is really cut off. Make sure that the power
distribution cabinet is maintained under power-off state.
2) When maintaining the power distribution cabinet section by section, please install isolation
devices at the adjoining area between cabinet with power and cabinet without power.
3) When operating the AC side vacuum circuit breaker, please wear insulating boots and insulation
gloves. Make sure the process is supervised by a specialist.
4) Before capacitor is discharged to ground, it’s forbidden to touch the cabinet of capacitor.
5) When maintenance is finished, check if there is any tool left in the power distribution cabinet
before connecting the power.
6) When maintenance is finished, remove the safety device and cut off the high pressure side
ground switch. Close the vacuum circuit breaker and supply power for operation.
Below are the items for maintenance of AC power distribution cabinet:
1 Make sure the metal frame of power distribution cabinet and the base formed steel zinc coated
bolts are connected well and the locking components are complete.
2 Power distribution cabinet should have the numbers, names and operating positions of the
controlled deviced marked clearly.
3 Bus bar joints should be connected tightly and in good shape. There should be no discharging and
blackening trace. Insulation parts are not loose or damaged. And the fastening bolts are not rusted.
4 The handcart and drawout set of power distribution cabinet should be able to be pushed or pulled
smoothly. The axis of dynamic and static head should be consistent with that of the static contact. The
static contact should contact closely.
5 The switch and main contact of the cabinet should not have burning or dissolving marks. Arc
blow-out cap should not be burnt or damaged. Make sure each wiring screw is securely fastened and
dust the cabinet.
6 Take out each subswitch cabinet from the drawer and fasten each wiring terminal. Check the
installation and wiring of current transformer, ammeter, and kilowatt-hour meter. Handlers should be able
to operate smoothly and reliably. Fasten the in and out wires of circuit breaker. Dust the switch cabinet
and the outgoing wire at the back of the power distribution cabinet.
7 The low pressure electric exothermic parts should be able to radiate well. Switch pressing board
should contact well. Signal indicators of signal circuit, buttons, optical character board, electric bell,
electric torch and accident electric clock should work normally and signal correctly.
8 Check the insulation resistance between wires of the circuits of cabinet, shield, desk, box, and
disk. Check the insulation resistance of these wires to ground. For supply line, it must be geater than
0.5MΩ; for secondary circuit, it must be greater than 1 MΩ.