METHOD FOR DETERMINATION OF LOAD STATIC CHARACTERISTICS AGAINST VOLTAGE WITH ABNORMAL DEVIATIONS PROTECTION

摘要

FIELD: electricity.SUBSTANCE: in the load unit sequential changes in voltage take place, on-load power and voltage are measured and translated into relative units. At that the measurement of the on-load power and voltage is performed before and upon each Ivoltage change in the load unit in the form of three-phase active power Pand Pand valid average phase voltage Uand U, where i=1, 2 is a serial number of change in a pair for Ivoltage change, index 1 corresponds to measurement before voltage change while index 2 - upon voltage change, and against them values of load controlling effect indices KPare determined for each pair of measurements. The pairs of measurements are excluded when values of the load controlling effect indices are outside the limits of the preset confidence interval. The received pairs of measurements Uand U, Pand Pare filtered against values of the load controlling effect indices KP, the first approximation of base power values is defined for each pair of measurements at Ivoltage change- for the first pair of measurements,- for the next pairs of measurements in regard to which the pairs of measurements Uand U, Pand Pare translated into relative units as per ratiosthereafter coefficients a, a, aof the polynomial approximant of the second degreeand mean-square deviation for voltage and power values are obtained in relative units of the obtained polynomialwhere N is the quantity of pairs of measurements, and against the preliminarily defined coefficients a, a, atogether with the values of Uand U, Pand Pbasis power values are specified for each pair of measurement in compliance with the ratiowith their further translation into relative units and repetition of operations for the determination of coefficients a, a, a, mean-square deviation ? and further specification of base power values Puntil the mean-square deviation ? is decreased either to the minimum preset value or a value of its increase beginning with each repetition.EFFECT: higher accuracy.2 dwg, 2 tbl