METHOD TO DETERMINE PARAMETRES OF THREE-PHASE THREE-WINDING TRANSFORMER EQUIVALENT T-CIRCUIT IN OPERATING CONDITIONS

摘要

FIELD: electrical engineering.;SUBSTANCE: proposed method comprises recording arrays of instantaneous voltages and currents in windings of all phases, when transformer HV-winding is connected to known-frequency power supply and its mean-voltage- and LV-windings are connected to loads. Actual voltages of all windings and transformation ratios are, then, determined as current voltage ratios of the windings. Transformation ratios are used to reduce currents and voltages of the mean- and LV-windings to those of HV-winding. Arrays of instantaneous voltage values in magnetisation circuit of the transformer equivalent circuit are formed, the voltage being taken to equal the mean-voltage winding voltage magnitude. Arrays of instantaneous values of voltage drop at HV-winding resistors are formed in the form of difference in instantaneous values of HV-winding voltage and that of magnetisation circuit. Array of instantaneous values of reduced voltage drop at LV-winding resistors in the form of difference in instantaneous values of magnetization circuit voltage and reduced voltage in LV-winding is formed. Now the array of instantaneous values of magnetisation current is formed in the form of difference in instantaneous values of current in HV-winding and the sum of instantaneous values of reduced currents in mean- and LV-windings. Then simultaneously, acting values of HV-winding currents, those of magnetisation current and reduced currents in LV-winding are determined from the arrays of instantaneous values of aforesaid currents. At the same time, losses of active power in HV-winding, magnetisation circuit and LV-winding are determined as average values for the period of instantaneous power values of appropriates windings, as well as reactive power losses in the same windings that are determined from arrays of instantaneous values of currents and voltages in the said windings via the area of E-I characteristics of these windings. Allowing for determined acting values of currents and losses of active and reactive power, active and reactive components of HV-voltage winding, magnetisation circuit and LV-winding resistance are determined.;EFFECT: determination of parametres of three-phase three-winding transformer equivalent T-circuit with all windings operated under load.;3 dwg, 3 tbl