System harmonic probability evaluating method based on Markov chain Monte Carlo method

Abstract

The invention belongs to the field of distributed generation power quality of a power distribution network of a power system and particularly relates to a system harmonic probability evaluating method based on the Markov chain Monte Carlo method (MCMC). The system harmonic probability evaluating method based on the MCMC comprises the steps that firstly, a harmonic injection current model of a point of common connection (PCC) is analyzed; secondly, the MCMC is deduced; thirdly, an MCMC sampling algorithm flow for harmonic probability evaluation of the power distribution network is put forward again; finally, typical quintuple harmonics and typical septuple harmonics injected into the PCC of the power distribution system are calculated according to the algorithm flow, based on the MCMC sampling method, for harmonic probability evaluation of the power distribution system, and thus a probability statistics characteristic value and a probability density curve of harmonic injection current of the PCC are obtained. According to the system harmonic probability evaluating method based on the MCMC, the influence of the ratio of linear loads to non-linear loads during different time periods is considered, solution is conducted according to the effective MCMC sampling method, the situation that historical measurement data and experience-based judgment results are excessively depended on is avoided, and thus results can be more comprehensive, more objective and more similar to the actual condition of the power distribution network.

Description

Technical field [0001] The invention belongs to the field of distributed power quality of power system distribution network, and in particular relates to a system harmonic probability assessment method based on Markov chain Monte Carlo method. Background technique [0002] Energy is an important material basis for human survival and development. In recent decades, human consumption of energy, especially electric energy, has reached an unprecedented level. The traditional large-scale centralized power supply model has gradually been unable to meet people's needs. Distributed power generation, as a power generation technology using renewable energy, is clean and pollution-free, and can fully and efficiently use distributed resources, and has broad application prospects. In 2011, my country's grid-connected new energy power generation capacity was 93.355 billion kWh, accounting for about 2% of the total power generation. As of the end of 2012, my country's grid-connected new energy ...

AI Technical Summary

Problems solved by technology

The traditional Monte Carlo method has the problem that it is difficult to sample from high-dimensional probability distributions. Therefore, the existing harmonic current analysis and evaluation methods mostly use data measurement or empirical estimation, and lack more scientific mathematical tools. The results are insufficient in terms of accuracy and timeliness

Especially for the power distribution system that uses a large number of distributed power sources connected to new energy sources, due to the random fluctuation characteristics of these power outputs that change with the environment, the severity of harmonic pollution is even more serious, so that the research on the problem become more complex, and the required analysis and evaluation methods should also be more scientific

Images