Assessing the Sensitivity of Relay Protection

Resumo

An assessment of sensitivity of the measuring elements of relay protection was performed. Based on simple examples of the generator-transformer unit protection from symmetrical short circuits, it was shown that the sensitivity factor is not a sufficiently objective measure of sensitivity of the relay protection. It was suggested to use a more objective measure, which is a characteristic of sensitivity to transient resistance at the fault location (dependence of the transient resistance, at which the protection stops tripping, on the fault location).