Surge Protection Methods Used for Electrical Equipment

The protection system of an electrical equipment is very important because it ensures its proper and continuous functioning. The overvoltages protection is a part of the protection system, particularly very important. This study highlights a number of methods, which can be applied to protect the electrical circuits in case of the occurrence ofovervoltages. Overvoltages caused by lightning strikes can lead to major faults that can appear in electrical circuits or can completely damage them. The paper also presents the combined methods of protection from overvoltages due to the unwanted overvoltages due to lightning strikes, applicable for all types of the electrical equipments with details and arguments for each method used. It also presents the methods of testing surge arresters/varistors with metal oxides, the measurement schemes together with the devices used and the results obtained. It is highlighted by electrical measurements the response time of varistors to transient conditions, that has a significantly impact of the effectiveness surge protection.