How does transformer be matched with circuit breaker?

How does transformer be matched with circuit breaker?

For example, the power transformer be 2000kVA, and the impedance voltage Uk=6%. The rated voltage of the low-voltage side winding is 400V/230V (line voltage/phase voltage).

Step 1: Calculate the rated current of the power transformer

Step 2: Calculate the short-circuit current of the power transformer

Step 3: Optional circuit breaker

The rated current Ie of the circuit breaker must be greater than the rated current In of the power transformer, and the ultimate short-circuit breaking capacity Icu of the circuit breaker must be greater than the short-circuit current of the power transformer.

Step 4: Determine the number of poles of the circuit breaker

The number of poles of the circuit breaker is related to the grounding form of the low-voltage distribution network. If it is a TN-C grounding system, the circuit breaker must use 3P; if the grounding form of the low-voltage distribution network is TN-S or TT, 4P can be used.

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