Arrester Thermal Stability Control: Implementing a Combination of Countermeasures During Power System Restoration: A Real Case Study

Power outage, also known as blackout, is inevitable despite all operator efforts. Accordingly, an exhaustive restoration plan should be prepared beforehand. Considering all the static and dynamic constraints of power systems during system restoration leads to a comprehensive restoration plan which, in turn, results in the alleviation of its negative impacts. One of the challenges in developing the restoration plan is switching transients in energizing no-load or lightly loaded transformers and its effect on other power system equipment, arresters in particular. In this article, a restoration plan in the Iran power system is studied, focusing on switching transients. First, the flux–current curve is plotted applying three different methods, utilizing the real standard test data of a transformer; then, the thermal effect of switching transients on an arrester existing in Iran electric grid is studied. Results yielded that the arrester may be damaged in the absence of preventive actions; therefore, a proper countermeasure which takes into consideration the frequency and voltage constraints, as well as the asynchronous operation of circuit breaker contacts, is proposed. The simulation shows that the proposed countermeasure guarantees arrester safety.