Impact of Shunt Reactor Overvoltages Switching in High Voltage System

Abstract

Reactor banks are crucial in reducing the voltage surge, also known as the Ferranti Rise that occurs on lengthy transmission lines that are lightly loaded with significant capacitive charging current. High frequency transients are introduced during the energising and the reactor bank’s de-energizing, which could cause the failure of the switching equipment’s insulation. This paper discusses many phenomena connected to reactor bank de-energization from an engineering perspective, as well as the use of circuit breakers for interrupting low inductive currents. For this reasons the circuit has been modified by connecting a circuit breaker with its series resistance in parallel with the shunt reactor as a mitigation method, and thus this method is able to ensure the suppression of the transient overvoltages through the shunt reactor and circuit breaker. The Alternative Transients Program (ATP-Draw) models and simulates the transients brought on by switching a shunt reactor to examine the current chopping brought on by switching reactor banks. At the smallest and highest levels of current chopping, overvoltages caused by de-energization were calculated. The simulation results showed that the proposed method has been significantly noted for overvoltages suppression, Where the voltage across the shunt reactor has been reduced from 475 KV to 279 KV and from S74 KV to 684 KV across the circuit breaker at current chopping value equal to 10 A.