What is the role of a closing resistor on an EHV breaker?

The closing resistor plays a crucial role in enhancing the operational effectiveness of an Extra High Voltage (EHV) breaker. Specifically, it serves to protect the current-carrying paths of the breaker contacts during operation. When closing the circuit, electrical components can face significant inrush currents, leading to arcing and potential damage to the contacts. The presence of a closing resistor helps to mitigate these adverse effects by limiting the initial current flow and thus preventing excessive stress on the contacts.

In doing so, the closing resistor ensures that the electrical contact surfaces do not experience excessive wear or damage due to high currents. This preservation of contact integrity is vital for maintaining the long-term functionality and reliability of the EHV breaker, ultimately providing crucial protection for the electrical system it serves.