Emergency control system for angular stability based on PMU data

Angular stability protection devices (ASPD) are used to maintain network capacity reserve before instability between power system areas in case of power system state approaching the limit. Application of phase difference (from PMU) of voltages at the points of interconnection between the areas makes ASPD adaptive to power system state changes since phase difference is more universal criteria of approaching to the limit than interconnection power flow. Phase difference reference should be chosen from the number of continuation power flows and transients analysis. The paper doesn’t consider that aspect. It addresses necessity of prevention operation in cases when phase difference reference may be exceeded by ASPD operation should be forbidden.