Power Flow Estimation based on Power Transformer Plate Data and Voltage Measurement

This paper proposes a algorithm capable of estimating the current and power flowing through the power transformer based on the plate data and the power transformer phase voltages. The proposal must be applied on power quality monitors when only voltage records are available. The installation of power quality monitors using voltage and current measurements could not be possible without shutdown the system to install current probes and the current signals are not so available as voltage signals. Measuring only the phase voltage at both sides of a transformer and using the proposed algorithm is a suitable solution to estimate the positive, negative, and zero sequence currents and the apparent power flowing through the transformer. The currents and power flow estimated could be useful when the power quality monitor is used to locate the voltage sag source. The performance of the proposed algorithm is assessed through a real time digital simulation case study in a Brazilian utility system where the accuracy and error sensibility are evaluated.