Determination of modern reliability indicators of relay protection and automation devices

   RELEVANCE. The reliability of power supply to consumers depends on the reliability of all elements of the power supply system, including relay protection and automation devices (RZiA). Knowing the current values of the reliability indicators of various devices makes it possible to take them into account when designing RPA, choosing more reliable devices, identifying shortcomings in RPA and performing work to eliminate them.
   THE PURPOSE. Due to the lack of open data on the current values of reliability indicators of relay protection and automation devices (RPA) of electric networks of 10-110 kV, the question of their determination on the example of power systems of various regions is relevant.

   METHODS. The authors present and analyze official statistical data on the number of emergency failures, false and correct actuations of relay protection and automation devices in the electric grid organization - branch of PJSC «Rosseti Center» – «Ore lenergo» for 2013-2021.

   RESULTS. In the course of the study, numerical values of the following reliability indicators of relay protection and automation devices were determined: the failure rate and the frequency of excessive triggering. Relay
protection and automation devices, for which reliability indicators have been determined, are used to implement arc protection, maximum current protection, automatic re-activation, differential protection of buses and transformer, transverse directional differential protection, gas protection of transformer, differential-phase protection.

   CONCLUSION. The values of the failure flow for different types of relays and microprocessor devices of the RPA are established, for example, for an electromechanical relay of the DZT-11 type used to implement differential protection of transformers with a higher voltage of 110 kV, the failure flow is 0,2 year^-1/100 pcs., and the frequency of excessive triggering is 22,22 year^-1/100 pcs. Conclusions are drawn about the need for measures to regulate the settings and maintenance of devices of various types.

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