Capacitor voltage transformer applied to harmonic measurement

Abstract

Along with mass application of huge-capacity nonlinear power equipment, particularly a power electronic device, in departments such as transportation, chemical industry, metallurgy, iron and steel, and coal, a lot of users hope to carry out continuous non-stop online test on the power equipment, and thus the invention provides an improved novel capacitor voltage transformer in which a capacitive voltage divider is additionally arranged to serve as a harmonic measurement element on the basis of the traditional capacitor voltage transformer. The improved capacitor voltage transformer not only has functions of a conventional capacitor voltage transformer, such as voltage metering, relay protection and carrier communication, but can also be used for measuring high-voltage and ultrahigh-voltage harmonic and observing grid voltage waveforms in real time. In addition, the capacitor voltage transformer can be directly used as secondary-side measurement equipment at the initial planning and mounting stage of a huge grid or a substation to be mounted onto a grid bus, and real-time observation can be realized when the system operates normally. Mounting and operation economy can be improved to a large degree.

Description

technical field [0001] The invention relates to a novel capacitive voltage transformer in the field of power systems. Specifically, new capacitive voltage transformers that can measure system harmonic voltage levels. Background technique [0002] With the massive application of large-capacity non-linear electrical equipment, especially power electronic devices, in transportation, chemical industry, metallurgy, steel, coal and other sectors, coupled with the increasing popularity of household appliances, harmonic problems in power grids have become increasingly prominent, deteriorating power quality , has caused great harm to the power system and power equipment. Therefore, many users pay more and more attention to the harmonics of the power grid, hoping to carry out continuous and uninterrupted online testing on it. [0003] Existing voltage transformers generally use class 0.2. When measuring the fundamental voltage, the allowable frequency deviation is very small, and th...

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Problems solved by technology

[0006] The present invention aims at the problem of distortion of the harmonic signal of the power grid measured by the current capacitive voltage transformer, and proposes an improvement

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