Three-phase imbalance adjusting method based on intelligent phase-change switch

Abstract

The invention discloses a three-phase imbalance adjustment method based on an intelligent phase-change switch. The method comprises the following steps of solving an abstracted switch state matrix anda three-phase current imbalance degree; generating a matrix corresponding to the phase sequence of the phase-change switch according to the number of switches in the power distribution area and the phase sequence corresponding to the phase-change switch; calculating the unbalance degree of the three-phase current according to the parameters acquired by the phase-change switch; establishing a model for the switching commutation frequency and the three-phase unbalance degree; establishing a target function of phase sequence adjustment based on the principle that the unbalance degree after adjustment is minimum and the adjustment frequency of the intelligent phase-change switch is minimum; solving the adjusted switch state matrix under the optimal condition; introducing a weight function toevaluate the commutation current and the action times of a single commutation switch in a period; and a feasible optimal commutation scheme being obtained after evaluation, and corresponding switch commutation being controlled. The method is advantaged in that the phase sequence can be continuously adjusted in real time, and a problem of three-phase imbalance is solved.

Description

technical field [0001] The invention relates to phase sequence adjustment of electric loads in a distribution network, which belongs to the field of low-voltage power distribution in a power grid, and in particular to a three-phase unbalance adjustment method based on an intelligent phase change switch. [0002] technical background [0003] Due to the existence of a large number of single-phase loads in the low-voltage distribution network area, the power load of the low-voltage distribution network is relatively complex, with a wide area, and most of them are single-phase power loads. Therefore, the actual power load cannot be evenly distributed on each phase of the distribution network, and the problem of three-phase imbalance is easily generated. As a result, the distribution transformer and line loss will be seriously affected, and the economic benefits of the power supply enterprise will be reduced. And the user's power quality is greatly affected. The impact of three-...

AI Technical Summary

Problems solved by technology

[0003] Due to the existence of a large number of single-phase loads in the low-voltage distribution network area, the power load of the low-voltage distribution network is relatively complex, with a wide area, and most of them are single-phase power loads. Therefore, the actual power load cannot be evenly distributed on each phase of the distribution network, and the problem of three-phase imbalance is easily generated. As a result, the distribution transformer and line loss will be seriously affected, and the economic benefits of the power supply enterprise will be reduced. and the user's power quality are greatly affected

The impact of three-phase imbalance on power quality is mainly reflected in: affecting the reliability of power supply, increasing the extra loss of the transformer, reducing the output of the distribution transformer, increasing the line loss, etc., and even burning the transformer in severe cases

[0004] The traditional three-phase balance optimization commutation method is to manually change the phase sequence of the load. In recent years, with the development of power electronics technology, intelligent commutation switches have been researched and developed by experts and scholars at home and abroad. The phase strategy is still relatively simple and not efficient

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