FIELD: electrical engineering; automatic emergency control of power systems. SUBSTANCE: in addition to checking voltages $$$ and $$$ at first and second points of power system chosen on condition that optimal simulation of equivalent electromotive forces of transmission is obtained under asynchronous conditions according to which angle $$$ between vectors $$$ of voltages $$$ and $$$ and relative slip $$$ of these vectors are measured, pre-asynchronous or asynchronous conditions detected in case absolute values of $$$ and $$$ are higher than desired values of $$$ and $$$, respectively, and pre-asynchronous or asynchronous condition is distinguished by no increase or increase in absolute value of $$$ above rated critical value $$$, respectively; proposed method also involves measurement of current at predetermined section of power system and voltages $$$ and $$$ at third and fourth points of power system chosen on condition that electric center of hunting is located between them only under asynchronous conditions on predetermined section; relative slips $$$ and $$$ of vector pairs $$$ as well as relationships $$$ are calculated, and signs of these relationships are determined; their noncoincidence is included as additional means for detecting pre-asynchronous or asynchronous condition. EFFECT: improved selectivity of method. 3 dwg
