SELECTING SWITCHES FOR SWITCHING INDUCTIVE LOADS: TECHNICAL ASPECTS AND PRACTICAL CONSIDERATIONS

In power systems, reactive compensation is a common and necessary practice to maintain the quality of electrical service. Disconnection of reactors or reactor banks is frequent, sometimes up to two or three times a day. Therefore, circuit breakers for this application must operate satisfactorily under the energization and de-energization processes of "inductive currents" that can cause the chopping interruption phenomenon, as well as in cases of magnetizing currents from unloaded transformers and load currents from induction motors. The proper selection of circuit breakers to operate inductive loads in medium-voltage systems is a critical aspect in the design and operation of electrical networks. Inductive loads, such as motors, transformers, and reactors, present unique challenges due to the voltage and current transients associated with their connection and disconnection. This article addresses the essential technical criteria for breaker selection, including interrupting capacity, surge resistance, and arc flash management. In addition, relevant international regulations are discussed, and case studies illustrating industry’s best practices are presented. The aim is to provide comprehensive guidance for engineers and designers seeking to optimize the reliability and safety of their electrical systems.