Phase voltage self-calibration method based on series-connection capacitors and used for single-phase overhead transmission line

Abstract

The invention provides a phase voltage self-calibration method for a single-phase overhead transmission line. Based on the space capacitor voltage dividing principle, a line and earth are taken as a large capacitor and subjected to voltage division, and air is taken as an insulation medium. A wire metal part is directly connected with an upper polar plate, a switch capacitor is connected in series between the wire metal part and the upper polar plate, the stray capacitance value of the upper polar plate for a wire is changed by changing the capacitance value of the switch capacitor, different voltage values are measured on a sampling capacitor, so that unknown stray capacitance and to-be-measured voltage can be calculated, and non-contact self-calibration of wire phase voltage is realized. The method meets the requirement of distributed devices of a distribution network and is better than the existing voltage measurement scheme.

Description

technical field [0001] The invention relates to a method for self-calibrating the phase voltage of a single-phase overhead transmission line based on a series capacitor, which is applied to an overhead line distributed voltage sensor. Background technique [0002] With the continuous development of my country's electric power industry, building a strong smart grid has become the future development direction. At present, my country's distribution network has a large number of lines, wide areas and long lines, and the environment is complex and the failure rate is high. The development of low-cost distributed monitoring devices can realize real-time online monitoring and fault location of the distribution network operation status. Operation is of great significance. [0003] Distributed and accurate measurement of phase voltage of overhead lines in distribution network is a difficult point. Currently widely used voltage sensors mainly include electromagnetic (PT), capacitive ...

AI Technical Summary

Problems solved by technology

Traditional PTs are affected by factors such as small capacity, high cost, complex insulation structure, ferromagnetic resonance phenomenon, and leakage inductance distributed capacitance, which gradually do not meet the needs of today's power grids.

CVT is mainly used in power grids above 330kV. It is bulky, expensive, difficult to install, and cannot meet the requirements of low-cost distributed devices.

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