关键词: 变频调速系统, 谐波, 畸变功率, 功率因数, 功率四边形, 现场数据

Abstract: In the frequency variation speed-regulation system,the high frequency harmonic current leads to distortion power N,and the power factor of the system,the input power factor of the invertor,is calculated by the ratio of the active power to the apparent power or by the consine of the angle included between fudamental harmonic current and source voltage.The calculation usually results in a deviation from the actual power factor.This paper gives.a new concept of the power quadrangle made up of S,P,Q and N,presenting the formula to calculate the actual power factor,demonstrating the numerical value relation among actual,total and displacement power factor.The conclusion in this paper has been proved by the field data measured from the oil transferring system with frequency variation speed-regulation in Daqing No.2 Oil Plant.

Key words: frequency variation speed-regulation system, harmonic, distortion power, power factor, power quadrangle, field data