순시전력 합성 개념을 이용한 가상주파수 3상 실효전압 계측기법

3-Phase RMS Voltage Measurement Method of Virtual Frequence using Instantaneous Power Component Concept

Abstract

This paper proposes a new measurement method using virtual power concept to measure the effective value of 3-phase voltage with variable frequency. The conventional effective value measurement method uses a method of integrating data sampled during one or half cycle of the power voltage and averaging it. In this method, since the effective voltage is calculated every cycle, a time delay occurs in the measured effective voltage and it is s a problem to measure the effective value of a device whose frequency varies from time to time, such as a generator. The proposed 3-phase voltage rms measurement method has an advantage that it can measure accurate voltage RMS value regardless of measurement frequency variation. In particular, there is an advantage in that it is possible to measure a 3-phase effective voltage rather than an average value of the effective voltage of each phase in a 3-phase unbalance voltage. In addition, the validity of the proposed method is verified by using the Psim simulation tool and the experimental results are analyzed by applying the proposed measurement algorithm to the actual three phase synchronous generator voltage measurement experiment.

Fig. 1 AC Voltage sampling method

Fig. 2 Simulation circuit

Fig. 3 3-phase voltage, current & Power

Fig. 4 Proposed simulation circuit

Fig. 5 simulation results at voltage balance

Fig. 7 Experiment results at voltage balance 1

Fig. 6 simulation results at voltage unbalance

Fig. 8 Experiment results at voltage balance 2

Fig. 9 Experiment results at voltage unbalance 1

Fig. 11 Experiment results at voltage unbalance 3 (LPF)

Fig. 10 Experiment results at voltageunbalance 2