Harmonic limit compliance evaluation accounting for phase angle diversity

Compliance with power system harmonics limits at the point of common coupling is becoming a significant concern for all electric utility customers using nonlinear loads inside their facilities. A simplified method to predict compliance (or not) is presented in this paper. The method automatically incorporates the potentially significant effects of phase angle diversity due to different loads on different plant buses and is based on an exact solution to modified fundamental-frequency power flow equations. Results are provided in simple, easy-to-use graphical format and account for variations in source voltage, load voltages, impedance magnitudes, X/R ratios and load powers. The use of the method for compliance estimation is demonstrated in a case study using a comprehensive time-domain simulation of an industrial plant with significant PWM ASD load.