DC circuit breaker action selection and treatment of common faults of low voltage circuit breakers

DC circuit breaker can be used in solar power generation system, working voltage up to DC750V, can quickly break the fault current of DC power distribution system, protect important components in solar power system - photovoltaic module from DC side reverse current and inverter The fault of the AC side feedback current caused by the fault, the DC circuit breaker ensures the reliable operation of the solar photovoltaic power generation system. The operating mechanism of the DC circuit breaker has the functions of quick closing and fast breaking, compact structure, small size and convenient use.

The following points should be noted for the selection of low voltage circuit breakers.

1 The rated current and rated voltage of the low-voltage circuit breaker shall be greater than or equal to the normal working voltage and working current of the line and equipment.

2. The limit on-off capability of the low-voltage circuit breaker should be greater than or equal to the maximum short-circuit current of the circuit.

3 The rated voltage of the undervoltage release is equal to the rated voltage of the line.

4 The rated current of the overcurrent release is greater than or equal to the maximum load current of the line.

The use of low-voltage circuit breakers to achieve short-circuit protection is superior to fuses, because when a three-phase circuit is short-circuited, it is likely that only one phase of the fuse will blow, causing a phase-failed operation. For low-voltage circuit breakers, as long as a short circuit is caused, the switch will trip and the three phases will be cut off at the same time. There are also other automatic protections. However, its complex structure, low operating frequency and high price make it suitable for high-demand applications such as power mains.