How to calculate the short circuit current of the cable?

If the two phases are shorted, divide the line voltage by the line impedance.

Calculation of short-circuit current.

If the voltage level is 6kV, the short-circuit current (unit ka, the same below) is equal to the total reactance x* divided by the short-circuit point (before the short-circuit point, the same below); If the voltage level is 10kV, it is equal to the total reactance x*; If the voltage level is 35kV, it is equal to the total reactance divided by x*; If the voltage level is 110kV, it is equal to the total reactance x*; If the voltage level is equal to 150 divided by the total reactance x*.

It is calculated based on the formula: id=ijz x * 6).

where ijz: indicates that when the reference capacity is 100mVA, the reference current (ka) is taken from 6kV, 10kV, 35kV, and 110kV, then 150kA.

Main parameters: SD: Three-phase short-circuit capacity (MVA), referred to as short-circuit capacity, check switch breaking capacity.

ID: The RMS value of the periodic component of the three-phase short-circuit current, referred to as the short-circuit current check, the switching current and thermal stability.

IC: The full current rms value of the first cycle of three-phase short circuit, referred to as the RMS value of the inrush current, checks the dynamic stability.

IC: Three-phase short circuit first cycle full current peak, referred to as inrush current peak check dynamic stability.

x: reactance ( ).

Among them, the short-circuit capacity of the system SD and the calculation point reactance X are the key.

Calculation of short-circuit current.

If the voltage level is 6kV, the short-circuit current (unit ka, the same below) is equal to the total reactance x* divided by the short-circuit point (before the short-circuit point, the same below); If the voltage level is 10kV, it is equal to the total reactance x*; If the voltage level is 35kV, it is equal to the total reactance divided by x*; If the voltage level is 110kV, it is equal to the total reactance x*; If the voltage level is equal to 150 divided by the total reactance x*.

The formula is calculated according to: id=ijz x * 6) where ijz: indicates that when the reference capacity is 100mva, the reference current (ka) is taken from 6kV, 10kV, 35kV, and 110kV, then 150kA.

Calculation of short-circuit current.

If the voltage level is 6kV, the short-circuit current (unit ka, the same below) is equal to the total reactance x* divided by the short-circuit point (before the short-circuit point, the same below); If the voltage level is 10kV, it is equal to the total reactance x*; If the voltage level is 35kV, it is equal to the total reactance divided by x*; If the voltage level is 110kV, it is equal to the total reactance x*; If the voltage level is equal to 150 divided by the total reactance x*.

The formula is calculated according to: id=ijz x * 6) where ijz: indicates that when the reference capacity is 100mva, the reference current (ka) is taken from 6kV, 10kV, 35kV, and 110kV, then 150kA.

Calculation of short-circuit current.

If the voltage level is 6kV, the short-circuit current (unit ka, the same below) is equal to the total reactance x* divided by the short-circuit point (before the short-circuit point, the same below); If the voltage level is 10kV, it is equal to the total reactance x*; If the voltage level is 35kV, it is equal to the total reactance divided by x*; If the voltage level is 110kV, it is equal to the total reactance x*; If the voltage level is equal to 150 divided by the total reactance x*.

The formula is calculated according to: id=ijz x * 6) where ijz: indicates that when the reference capacity is 100mva, the reference current (ka) is taken from 6kV, 10kV, 35kV, and 110kV, then 150kA.