Variable Shunt Reactors with On-Load Tap-Changers for the Efficient Compensation of Over-Voltages Caused by Capacitive Loads

Summary

Balanced reactive power in the power grid is an important factor for network operations to keep losses low and avoid over-voltages on networks. A sophisticated management of reactive power might be a key component for stable grid operation. Depending on the network design different applications for shunt reactors exist. A widely used method to compensate long power lines is to switch in and out shunt reactors depending on the actual load situation to compensate reactive power of the power line. This is usually done with circuit breakers and the number of operations depends on the daily load fluctuation on the line. A circuit breaker is capable of approximately 10'000 operations before maintenance; therefore the wear of the circuit breaker might be extensive for such applications. An additional disadvantage is that only the full reactive power of the shunt reactor can be switched in and out. To optimize losses on the line, discreet steps of reactive power are more useful. This can be achieved efficiently by using an on-load tap-changer (OLTC) to regulate the reactive power of the shunt reactor. Using OLTCs in shunt reactors requires consideration of certain technical aspects for the OLTC and the shunt reactor. Some of these aspects shall be discussed.

Additional informations

Authors

Pajic, D'Aquila, Patil, Rajaraman