The calculation method for influence of photovoltaic power generation system on three-phase voltage unbalance degree of distribution network

Abstract

Abstract: Aiming at the deficiency of traditional deterministic power flow calculation in the evaluation of three-phase voltage unbalance caused by distributed photovoltaic power stations connected to the distribution network, a method based on multi-point linearization semi-invariant probabilistic power flow and importance sampling was proposed to evaluate the unbalance degree of distribution network. First, given the limitations of the Beta distribution, the adaptive nonparametric kernel density estimation method was adopted to characterize the photovoltaic output and load fluctuation random process to improve the modeling accuracy, and then the method of piecewise linearization semi-invariant was used to perform stochastic trend analysis to reduce the error due to uncertainty. Afterward, the mixed Copulas connect function was constructed to calculate the unbalance of the public connection point. Finally, the sampling method was used to get the mean value of unbalance degree for evaluation. In the end, the effectiveness of the proposed method was verified by the simulation analysis of the IEEE33 node system.

Key words: three-phase voltage unbalance degree, probabilistic power flow, kernel density estimation, semi-invariant method, M-Copula function

CLC Number:

TM711

CHEN Wei, NI Yuan-hong, JI Qing-chun, WANG Zhong-fei, HE Feng. The calculation method for influence of photovoltaic power generation system on three-phase voltage unbalance degree of distribution network[J]. Journal of Lanzhou University of Technology, 2023, 49(2): 76-82.

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