High Accuracy Selective Element For Electric Power Quality Indexes Measurement

摘要

It is necessary to carry out two selective operations for high accuracy measurement some of Electric Power Quality Indexes (EPQI): first of all it is necessary to pick up fundamental harmonic voltages from a spectrum of three phase voltage system, then, a positive, negative and zero symmetrical components. A selective devise must provide minimal amplitude and phase error in the real conditions - variation of an angular frequency of voltages. It is proposed an adaptive amplifier with spectrum conversion. The adaptive amplifier is described by non-linear differential equations with variable coefficients that may be represented by break functions. The generalized method of linearization by the describing function for static and dynamic analysis of this device is proposed. The paper illustrates the unique data of this amplifier.