High precision medium voltage distribution line true equivalent model and parameter calculation method thereof

Abstract

The invention provides a high precision medium voltage distribution line true equivalent model and a parameter calculation method thereof. The model comprises A phase impedance used for simulating the self-impedance and mutual impedance of an A-phase wire, B phase impedance used for simulating the self-impedance and mutual impedance of a B-phase wire, C phase impedance used for simulating the self-impedance and mutual impedance of a C-phase wire, and G impedance used for simulating the earth return and interphase parameters. According to the invention, based on the power system analysis theory and according to the engineering practice of a distribution line, the influence of the transmission wires, among the wires and among the wires, the earth and the earth return and other factors are taken into account; an inverse-pi-shaped four-capacitor G impedance model structure is creatively provided to precisely simulate electromagnetic coupling among the wires and among the wires, the earth and the earth return; positive sequence and zero sequence parameters of the line are precisely simulated; and the cascade structure of multiple groups of lumped-parameter elements is used to meet the equivalent simulation of the distribution line of amplitude-frequency and phase-frequency response precision in a high frequency range.

Description

technical field [0001] The patent of the invention belongs to the technical field of power distribution equipment, and specifically relates to a high-precision power distribution line true-type equivalent model and its parameter calculation method considering high-frequency transmission characteristics. [0002] technical background [0003] With the rapid development of smart grid, the coverage and application scale of distribution automation system are expanding day by day, which provides effective technical means for improving the reliability of power supply of distribution system. Distribution automation system restores power supply to healthy areas by quickly isolating faulty areas, which is of great significance to improve power supply reliability. The key technology relies on intelligent power distribution terminals such as distributed FTUs, DTUs and fault indicators to monitor the operating status of distribution lines in real time. According to the obtained voltage a...

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Problems solved by technology

However, there is no mention of the equivalent method for accurately calculating the line parameters such as the self-impedance, mutual impedance, ground capacitance, and interphase coupling capacitance of the wires, and the setting of the number of segments of the π-type structure with centralized parameters is not considered. The high-frequency phase-frequency characteristics and amplitude-frequency characteristics of the voltage are significantly different from the equivalent actual line, which cannot substantially reflect the current and voltage signal characteristics of the real distribution line under various operating conditions

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