Efficiency of relay protection of power system

Efficiency and reliability are the main indexes of the relay protection functioning quality and quality of automatic equipment (RPA) for power systems. The provision of high level reliability and efficiency is highly important for Russia nowadays due to the beginning of the broad-implementation of the micro-process terminal relay devices. The authors developed the methods of assessment and optimization of the RPA reliability of power systems on the levels of development and projection. Both the reliability of actuation and failure to operate are taken into account. It is shown that in order to provide high result reliability it is not necessary to always switch the components of relay protection by the scheme OR. Sometimes it is better to use the scheme AND. On the most important objects it is likely to use three sets, working on the algorithm ldquotwo out of threerdquo.