High-order cumulant-based random harmonic power flow calculation method

Abstract

The invention discloses a high-order cumulant-based random harmonic power flow calculation method. The high-order cumulant-based random harmonic power flow calculation method comprises the steps of acquiring a harmonic current sample of a harmonic source having same time sequence in a power grid; performing correlation decoupling on the harmonic current sample to obtain a harmonic current, whereineach harmonic current is independent; calculating high-order moment and high-order cumulant of a harmonic current, and determining a reference running point of a power grid according to the higher moment and the high-order cumulant of the harmonic current; performing linear correction on a preset harmonic power flow model at the reference running point, and calculating the higher moment and the high-order cumulant of the harmonic voltage of the power grid according to the harmonic power flow model after linear correction; and calculating probability density of the harmonic voltage according to the higher moment and the high-order cumulant of the harmonic voltage. By the method, the condition of relatively small harmonic monitoring sample and harmonic randomness and correlation can be adapted, the calculation quantity of random harmonic power flow is effectively reduced, and the probability density analysis accuracy of the power grid harmonic is improved.

Description

technical field [0001] The present invention relates to the field of power quality analysis and control, in particular to a random harmonic flow calculation method based on high-order cumulants. Background technique [0002] The existence of harmonics is one of the most important power quality problems in power grids. Power electronic equipment such as converter devices, saturated equipment such as transformers, arc equipment such as fluorescent lamps and electric arc furnaces, will generate harmonics and inject them into the power grid, becoming the main harmonic source of the power grid. Harmonics propagate through the power grid, reducing power quality, causing increased network loss in the power grid, overheating of rotating motors and transformers, malfunctions of relay protection and communication equipment, etc., threatening the safety of the power grid and user equipment, and even causing certain economic losses. Therefore, it is of great significance to study the p...

AI Technical Summary

Problems solved by technology

When the monitoring sample size is large, the existing technology mainly uses the Monte Carlo method to obtain the harmonic distribution results of the power grid through repeated sampling calculations. This method requires a huge amount of calculation; and the harmonic injection of the harmonic source, due to time and space There may also be correlation, which will affect the stochastic analysis process, resulting in the inability to accurately analyze the harmonic probability density of the power grid

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