Single-phase overhead transmission line phase voltage self calibration method based on shunt capacitor

Abstract

The invention relates to a single-phase overhead transmission line phase voltage self calibration method. By means of a space capacitor voltage dividing principle, a line and the ground are regarded as a bulky capacitor to divide voltage across the line, and air is taken as an insulating medium. An upper pole plate of a sampling capacitor is connected with the surface of a high-voltage wire insulating layer, a lower pole plate is hung in the air, a switch capacitor is connected in parallel with a capacitor between the upper pole plate and the high-voltage wire, by changing the capacitance value of the switch capacitor, the stray capacitance value between the upper pole plate and the wire is changed, the sampling capacitor can measure different voltage values, and therefore each unknown stray capacitance value and the voltage value to be measured can be worked out, and single-phase wire phase voltage non-contact self calibration is achieved. The single-phase overhead transmission line phase voltage self calibration method is suitable for distribution network distributed devices, and is better than existing voltage measuring schemes.

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 parallel 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), capacitiv...

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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