Research On Separation Method, Experiment And Application Of Distribution Network Harmonic Wave Basing On Characteristic Vector

As a result of nonlinear load, there will be harmonic wave pollution in distribution network, which seriously affected the operating safety of power system, communication equipments, monitoring meter and peripheral devices, and leads to varieties of harm and hazards. In recent years, the source composition of distribution network power harmonic wave becomes more and more complex and the characteristics of hybrid harmonic wave becomes more and more fuzzy along with the developing of distribution network and further application of distribution generation. Faced with this trend, it seems difficult for existing harmonic monitoring device to divide governing responsibility among harmonic wave sources. In additional, because of the fuzziness of characteristic spectrum of hybrid harmonic wave, the governance effect of passive power filter may be deteriorated, and the cost of application of active power filter costs too much since the demand capacity of distribution network harmonic governance is quite large. Aiming at this problem, this thesis do analysis on harmonic wave hybriding process from the perspective of reverse thinking, do research on separation method, experiment and application of distribution network harmonic wave, the specific research contents are as follows:① Aiming at the disadvantage of traditional harmonic wave fast Fourier analysis method, do comprehensive comparison among window functions and interpolation algorithms, form a fast Fourier harmonic analysis method basing on windows and interpolation, tackle the problem of spectrum leakage and fence effect resulting from asynchronous sampling through weighted intercepting of Blackman window function and adjustment of Lagrange interpolation algorithm, so that the computational accuracy of harmonic wave analysis can be significantly improved in the context of instantaneity of calculation result. After that, harmonic wave characteristic parameters series is formed with harmonic wave analysis result;② Make simulation experiment on fast Fourier harmonic analysis method basing on window and interpolation, do theoretical analysis and simulating model calculation on common harmonic wave sources to verify the correctness of fast Fourier harmonic analysis method basing on window and interpolation and acquire fundamental characteristic trend of them. After that, do algorithm experiment on separation method of hybrid harmonic wave with data from a calculating sample, experimental results show that separation method of hybrid harmonic wave is able to realize real-time monitoring and analysis on working load rate, injecting harmonic current and communication rate to hybrid harmonic wave of each harmonic wave source accurately;③ Take the thought of equivalence between algebra problem and geometric problem; describe the hybriding process of harmonic waves in linear space. Raise the notion of characteristic vector innovatively and introduce it into the research on separation method of hybrid harmonic wave, take information entropy maximization as target to do feature extraction on characteristic vector of harmonic waves, solve separation equation of hybrid harmonic wave to achieve the aim to do real-time monitoring on harmonic sources’ working load rates, injecting harmonic currents and contribution rates to distribution hybrid harmonic wave;④ Take field experiment in actual distribution network administrated by Suining power supply branch company of Sichuan province. Do analysis according to harmonic wave source investigation result and monitoring data, extract characteristic vector of each harmonic wave source and complete the calculation of distribution network hybrid harmonic separation. Basing on calculation result, determine the configuration scheme of passive power filter and advise local power grid company to take it for harmonic wave suppression, monitor and collect harmonic wave data from distribution transformer under different governance strategies and do analysis on governance effect and the result shows that harmonic suppression measure proposed on basis of calculation result can suppress harmonic wave pollution of distribution network and the governance effect of which is significantly superior than traditional harmonic suppression measure.