Power system protection relay testing moving from certification testing to application testing

The increased utilization of power systems, the focus on cost reduction and the increased experience with numerical digital protection relays have initiated a shift from independent certification testing to independent application testing. Application tests are driven by the application and are generally subjective. Tests depend on many user-specific parameters: the type of network, network operation and reliability requirements. Application testing allows discovery of the protective relay behaviour for fault conditions of the power network and take away an uncertainty factor when applying new technology based protection relays.