ON-LOAD TAP CHANGER POSITION DETERMINATION USING USING CURRENTS DATA FROM SCADA

A practical check of the position of the On-load tap changer (hereinafter: OLTC) using the primary and secondary currents of transformers equipped with a OLTC using the currents obtained from SCADA (Supervisory Control And Data Acquisition) is considered. The equation for determining the position of the OLTC using currents data is shown. In SCADA, previously data on one primary current and one secondary current were obtained from remote control via measuring transducers, and more recently from microprocessor protection devices. The accuracy of determining the position of the OLTC in this way depends on errors: measuring transducers of remote control or analog inputs of microprocessor protection devices, transmission ratio of power transformer, current transformers and due to magnetizing currents (no-load current). The results of practical verification of data obtained from SCADA were processed with the aim of confirming applicability and improving reliability in certain parts of transmission and distribution of electricity: automation, protection, supervision and signaling. The difference between the calculated and actual position of the OLTC obtained from the data on the primary current and the secondary current from SCADA for several transformers is shown and discussed. Errors due to rounded readings were pointed out and the possibility of correction was considered