Phase sequence identification adaptive method applied to electric energy quality management device

Abstract

The invention discloses a phase sequence identification adaptive method applied to an electric energy quality management device. The method comprises the steps of (1) setting the number of sampling fundamental wave periods SAM_N for phase sequence judgment, and recording sampling location numbers of line voltage US12, US23 peaks in each fundamental wave period; (2) calculating the difference of the two sampling location numbers at the end of the period number SAM_N, and respectively accumulating a positive ordinal number POS_N and a negative ordinal number NEG_N based on a range to which the difference belongs; (3) judging an incoming line voltage phase sequence based on values of the positive ordinal number POS_N and the negative ordinal number NEG_N; (4), maintaining a conventional algorithm when the phase sequence is positive, interchanging voltage sampling values of the two lines and taking the negative when the phase sequence is negative so as to convert the negative phase sequence into the positive phase sequence; and (5) calculating a compensation target value correctly through interchanging control strategies when the phase sequence is negative so as to realize correct compensation management of the electric energy quality management device. According to the invention, the incoming line voltage phase sequence is judged in an adaptive manner, and the control strategy is adjusted automatically, so that the electric energy quality management device is enabled to have no requirements on an incoming line connection method and the phase sequence, and the adaptability of the device is enabled to be enhanced.

Description

technical field [0001] The invention belongs to the technical field of low-voltage power grid power quality control, and in particular relates to a phase sequence identification self-adaptive method applied to a power quality control device. Background technique [0002] With the increasing degree of electrification and the widespread use of large and medium-sized motors and power electronic devices, these electrical equipment generate a large amount of reactive power and harmonics, which affect the efficiency of the power grid and the quality of power supply, and cause pollution to the power grid. The power quality control device (APF , SVG) to effectively control grid pollution, and its application is becoming more and more extensive. [0003] Before the power quality control device is connected to the grid, it is necessary to detect the phase sequence of the three-phase voltage of the grid, so that the device can work under the positive sequence of the incoming line volta...

AI Technical Summary

Problems solved by technology

However, in most industrial occasions, because most electrical equipment has no requirements for voltage phase sequence, on-site personnel pay little attention to voltage phase sequence, and there is no phase sequence mark on three-phase cables. In order to make the power quality control device work normally, it is necessary to The phase sequence detection and judgment of the three-phase voltage of the power grid is time-consuming, time-consuming and expensive to detect equipment resources, so as to develop a control method suitable for the phase sequence of the field power grid voltage, which has research and application value

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