CONTROL OF PROTECTION RELAY

摘要

A protection relay (700), comprising means for measuring an input parameter value for the protection relay, means (706) for determining a calculation parameter value based on an inverse definite minimum time curve defining a relationship between the input parameter value and a predetermined threshold value of the input parameter, wherein the calculation parameter values are divided into two or more zones and restricted with zone-specific dividers and means (712) for adding the restricted calculation parameter value to a cumulative sum of the calculation parameter, the cumulative sum of the calculation parameter being usable in a calculation equation for determining an operate (619) and/or reset condition (615) of the protection relay.