Study On Power Measurement Of Electric Power System Under Nonsinusoidal Signals

Sinusoidal power theory in power system is mature. Traditional sinusoidal powertheory is not feasible for nonsinusoidal condition. Nonsinusoidal power theory is a hottopic for the domestic and overseas researchers. In this dissertation, the state of study onthe sinusoidal and nonsinusoidal power was introduced, to research the universal powertheory for arbitrary waveform and to find the proper way of power measurement. Themajor work as follows:Traditional nonsinusoidal power is only suitable for multi-frequency integerharmonics and finite periodic. A power measurement method was proposed based on theexpanded Prony algorithm.A mathematical model for measure electric power undercontaining non-integer harmonics and quasi-periodic signals was built. Use theexpanded Prony algorithm for harmonic detecting. This method could calculateharmonic power and electric power accurately on limited sampling window condition.Simulation result verified the feasibility and the accuracy of the present method.The existing nonsinusoidal instantaneous power theory has no clear physicalmeanings. The instantaneous power theory was proposed based on parameteridentification. Based on load characteristic, the equivalent model in time domain wasbuilt. The total least squares estimate method was used to identify the time-varyingparameters of load. The mathematical model and approach of measurement forinstantaneous active and reactive power was given. This method of instantaneous powerhas a distinct physical meaning. It is feasible for arbitrary nonsinusoidal voltage andcurrent, especially of non-periodical waveforms.Through using the instantaneous power theory based on parameter identification,the method of active and reactive power measurement, harmonic source identificationand system compensation was researched. Based on the relationship instantaneouspower between active, reactive power, measure the active and reactive power undernonsinusoidal condition. Using the instantaneous power theory based on parameteridentification for harmonic source identification, judge the harmonic responsibility ofload. The tracking compensation technique based on minimizing transmission loss isable to eliminate current distortion of harmonic sources.Build the simulation model under nonsinusoidal signals condition, to research theinstantaneous power theory based on parameter identification. Compared with the existing power measurement method, it points out the effectiveness and feasibility ofthe instantaneous power theory based on parameter identification and its measurementand application method.