Selection Of High Voltage Electrical Appliances

- Sep 04, 2017 -

The basic requirement of high voltage electrical apparatus is to ensure that the electrical equipment runs safely in the condition of normal operation or failure. The rated voltage and rated current of the appliance must meet the requirements of the power supply.

1 choice of high voltage circuit breaker

The main parameters of HV circuit breaker are rated voltage and rated current. The rated voltage of the circuit breaker is not less than the operating voltage of the device, and the most important parameter is the rated short-circuit opening power Flow ID, Max and rated short-circuit closing current.

A. Rated short-circuit open power Flow ID, max

When the operating voltage of the device is at the same time as the rated voltage of the circuit breaker, the circuit breaker can reliably cut off the maximum short-circuit current when a short-circuit fault occurs, that is, at the rated voltage of the circuit breaker. For circuit breaker short-circuit open power Flow ID, max, local power supply departments have clear requirements.

If the operating voltage of the device is lower than the rated voltage of the circuit breaker, when a short-circuit fault occurs, the short-circuit breaking current should not be greater than the rated short-circuit of the circuit breaker.

b. Rated short-circuit closing current

Rated short-circuit closing current (peak) requirements for circuit breakers: maximum short-circuit current that can be closed at rated voltages. Once the breaker is in short circuit condition (the probability of using the automatic reclosing device is large), the contactor of the breaker should be intact.


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