Circuit Breaker Restriking Voltage Estimation for 132 kV Systems

The restriking voltage is the transient voltage that appears across the circuit breaker contacts immediately after the arc is extinguished. Its peak value is critical for ensuring the circuit breaker can successfully interrupt the circuit.

Calculating Maximum Restriking Voltage

A common approximation for the maximum peak value of the restriking voltage ($V_{Restrike\_max}$) is twice the peak phase voltage ($V_{peak\_phase}$) of the system. The peak phase voltage is derived from the line-to-line voltage ($V_{LL}$).

1. Calculate Peak Phase Voltage:

   The system voltage is given as line-to-line ($V_{LL} = 132$ kV).

   The RMS phase voltage is calculated as: $V_{RMS\_phase} = \frac{V_{LL}}{\sqrt{3}}$ $V_{RMS\_phase} = \frac{132 \text{ kV}}{\sqrt{3}} \approx 76.21 \text{ kV}$

   The peak phase voltage is obtained by multiplying the RMS phase voltage by $\sqrt{2}$: $V_{peak\_phase} = V_{RMS\_phase} \times \sqrt{2}$ $V_{peak\_phase} = \frac{132 \text{ kV}}{\sqrt{3}} \times \sqrt{2} \approx 107.78 \text{ kV}$

2. Calculate Maximum Restriking Voltage:

   Using the approximation $V_{Restrike\_max} \approx 2 \times V_{peak\_phase}$: $V_{Restrike\_max} \approx 2 \times 107.78 \text{ kV}$ $V_{Restrike\_max} \approx 215.56 \text{ kV}$

Conclusion

The maximum value of the restriking voltage across the circuit breaker contacts in a 132 kV system is approximately 215.56 kV.