EQUIVALENT EXTERNAL REACTANCE DETERMINATION FOR A POWER PLANT OPERATING I N A COMPLEX ELECTRIC POWER SYSTEM

An experiment-based computation method for determining power plant equivalent external circuit parameters is presented. Application of this method offers an opportunity to significantly simplify the power plant stability computations, and facilitates development of the equipment intended for real excitation systems checking and adjustment. Development of electric power systems is marked by a growing number of the power plants equipped with voltage regulators providing power system stabilization CAVR3. Proper computer-- aided stability analysis of the power plants now in service and being designed appears to be the topical task of today. The steady-state stability is limited by the ranges of natural oscillation stability. The accuracy of determining the limits of oscillation stability and transients at heavy disturbances is strongly dependent on the thoroughness of modeling the excitation control sys: ems at the power plants under consideration. In the sets of programs used for practical design and dispatcher calculations [1 – 2], much attention is paid to detailed description of electric networks and load centers of large power areas. The vast scope of the program prevents from giving a comprehensive idea of excitation control systems and due consideration of real instrumentation. As a rule, an assumption is taken that electromotive force beyond the reactance X'd is constant. These sets of programs are efficient for solving the problems of network planning, but do not provide the possibility to assess stability of a definite station For these assessments, the original circut of a power system is usually substituted by an equivalent circuit with less number of node points [3 – 7]. However, in most complex power system investigations only a rough approximation is reached. The procedure of equivalent external reactance determination is quite complicated, it requires a great number of initial parameters to be set a priori and does not rule out possible errors.