Interphase electrical susceptance configuration method considering active power balancing of two phases

Abstract

The invention discloses an interphase electrical susceptance configuration method considering active power balancing of two phases. The method comprises the steps of 1) continuously acquiring active power data of three phases at each moment on schedule of a bus at a low-voltage side of a power distribution transformer for a month, and performing split-phase calculation on the acquired active powerdata to obtain an average value of an active power of each phase; 2) judging whether the active unbalance of the three phases exceeds 25% or not, if yes, selecting two phases with maximum active power and minimum active power as configuration phases; 3) judging whether a capacitor or an inductor shall be connected in parallel according to a phase sequence relation between the two configuration phases; and 4) measuring voltage values of the two configuration phases, and calculating the finally-configured capacitance or inductance capacity according to a power balance estimation formula. According to the method, interphase interface of the active power is performed by susceptance bridging, the two phases with maximum active power difference are basically balanced, the unbalance degree of the three phases is effectively reduced, so that the purposes of reducing loss of a circuit and the power distribution transformer and improving the load bearing capability of the power distribution transformer are achieved.

Description

technical field [0001] The invention relates to a configuration method of interphase susceptance in a low-voltage distribution transformer area, in particular to a configuration method of interphase susceptance considering two-phase active power balance. Background technique [0002] As the terminal link in the power system, the low-voltage distribution network connects the power grid and the majority of users, and is closely related to the daily life of residents. However, due to the long-standing problems of weak grid structure and insufficient funds for transformation of the distribution network, there is still a gap between the power consumption level and the international advanced level. Therefore, in recent years, my country has increased the capital investment and transformation of distribution network. In 2015, the National Development and Reform Commission and the National Energy Administration successively formulated the "Guiding Opinions on Accelerating the Const...

AI Technical Summary

Problems solved by technology

On the one hand, with the increase of load type and power consumption, the proportion of single-phase load gradually increases; Impulsive industrial power and civilian power and other equipment are directly connected to the distribution network, injecting a large amount of negative sequence and harmonic current into the power grid, thus greatly aggravating the imbalance of the distribution network

The unbalanced three-phase load will cause great harm to the power system and electrical equipment. On the one hand, it will increase the active power loss of the line and distribution transformer, increase the operating temperature of the distribution transformer, reduce the power of the distribution transformer and limit the distribution transformer. Load bearing capacity, on the other hand, will affect the output power of the motor and increase the temperature of the winding, resulting in a neutral point voltage shift, resulting in asymmetrical three-phase voltage, and in severe cases, it will burn out the user's electrical appliances

Among them, the principle of the existing capacitive regulating device to control the three-phase imbalance is based on the ideal compensation network proposed by the Danish professor C.P. Steinmetz (C.P. Steinmetz). This theory is only applicable to the neutral point ungrounded system. Most of the network is a three-phase four-wire system; even though part of the research is carried out for the three-phase four-wire system, the configuration method of capacitors and inductance is relatively complicated, which is not suitable for engineering practice. Therefore, it is necessary to propose a simplified and practical The phase-to-phase susceptance configuration method improves the power quality of the three-phase unbalanced station area

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