Capacitance type voltage transformer harmonic voltage measurement method and device

Abstract

The invention discloses a capacitance type voltage transformer harmonic voltage measurement method and device. The method comprises the following steps that: establishing the equivalent circuit modelof a capacitance type voltage transformer; according to the equivalent circuit model, establishing a relational expression between the transfer impedance of the capacitance type voltage transformer and primary side current and a relational expression between the transfer impedance of the capacitance type voltage transformer and secondary side voltage; establishing a ternary nonlinear equation setcontaining the primary side current, the secondary side voltage and stray capacitance in the equivalent circuit model; and solving the ternary nonlinear equation set, according to the solved value ofthe stray capacitance, calculating the equivalent impendence of the capacitance type voltage transformer, and according to a primary side harmonic current signal which is actually measured when the capacitance type voltage transformer operates, calculating a primary side harmonic voltage signal. By use of the method, the technical problems in an existing capacitance type voltage transformer harmonic voltage measurement method that a structure is complex, cost is high, reliability is difficult in prediction and the method is not suitable for field measurement since the capacitance type voltagetransformer needs to be transformed or depends on a high-voltage harmonic source can be solved.

Description

technical field [0001] The present application relates to the technical field of transformers, in particular to a method and device for measuring harmonic voltages of capacitive voltage transformers. Background technique [0002] Capacitive voltage transformer (Capacitor Voltage Transformer, CTV) is divided by series capacitors, and then stepped down and isolated by electromagnetic transformer, as a voltage transformer for meters, relay protection, etc., obtained in the power system a wide range of applications. [0003] With the increasing of nonlinear loads, the measurement of harmonic voltage has become a necessary requirement in the power industry to ensure the stable operation of the system. Therefore, the accurate measurement of harmonic voltage has become a key research direction for those skilled in the art. The existing methods for harmonic measurement using capacitive voltage transformers are: [0004] 1. On the basis of the traditional capacitive voltage transfo...

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Problems solved by technology

[0008] The embodiment of the present application provides a method for measuring the harmonic voltage of a capacitor voltage transformer, which is used to solve the existing problems in the existing method of measuring the harmonics of a capacitor voltage transformer. Harmonic source, resulting in complex structure, high cost, unpredictable reliability and technical problems that are not suitable for on-site measurement

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