Research On Algorithm Of Power Parameters Measurement On The Base Of Asynchronous Sampling

With the rapid development of economy and the improvement of people’s living quality, individual users and enterprises put forward higher demands on the quality of power supply when they have an increasingly demand of power energy. Accurate and real-time measurement for power network parameters has importantly realistic significance to protect the safety and stability of power running.This thesis focuses on the research of power network signal measurement methods about main parameters including base wave frequency, phase, amplitude, harmonics and inter-harmonics, mainly aiming at satisfying both high accuracy and high efficiency’s demands by the innovation of the measurement algorithm. The whole measurement algorithm uses a combination of time and frequency domain method, basing on power network’s signal high-speed, non-synchronous sampling.Time-domain algorithm, making full use of the advantage of high sampling rate, being given by this paper, can gain a high precision of the base wave frequency, then it has a low computation load, high measuring precision. Soft-synchronization sampling, basing base wave frequency from the time-domain measurement method, is the transformation from the time-domain to frequency-domain method. The study of the error analysis proves that soft-synchronization sampling is feasible and valuable. Single frequency components, after inspection by judgment method of spectrum interference, use the spectrum correcting methods including phase-difference method of time-window translation and FFT+FT method to get high-precision parameters. As the results the simulation, the former’s precision is higher and has stronger anti-noise property. To the question of intensive spectrum from harmonics and inter-harmonics, this paper probes into the zoom spectrum analysis method based on complex analytic band pass filter, which refine the selected frequency range, improve the frequency resolution. The ZoomFFT method can get high accuracy of intensive spectral components when it combined with my peak searching algorithm and my proposed the picket fence effect correction method by looking-up data table.This paper completed the algorithm design and simulation for power network parameters measurement finally. The whole algorithm was proved to be high-efficiency after testing by adding different random noise and analyzing the measurement results, and can meet the requirements of high precision and real-time measurement.