Capacitor voltage transformer (CVT) medium loss test method based on resonance feature

Abstract

The invention discloses a capacitor voltage transformer (CVT) medium loss test method based on a resonance feature. The method comprises the following steps: establishing a resonance circuit model of a CVT; maintaining total currents of a circuit unchanged, and obtaining an active power increment and a reactive power increment of the resonance circuit model at a resonance state and disresonance state; and according to tg delta1=tg delta2=delta P / delta Q, obtaining medium loss of a high-voltage capacitor packaged with an intermediate-voltage capacitor and medium loss of the intermediate-voltage capacitor, wherein tg delta 1 is the medium loss of the high-voltage capacitor packaged with the intermediate-voltage capacitor, and tg delta 2 is the medium loss of the intermediate-voltage capacitor, delta P is the active power increment of the resonance circuit model at the resonance state and the disresonance state, and delta Q is the reactive power increment of the resonance circuit model at the resonance state and the disresonance state. According to the invention, by use of the resonance feature of a CVT circuit structure, an established CVT medium loss test model based on the resonance feature is more accurate compared to a conventional normal polarity method, reverse polarity method and self-excitation method test model.

Description

technical field [0001] The invention relates to the technical field of dielectric loss testing, in particular to a method for testing dielectric loss of a capacitive voltage transformer based on resonance characteristics. Background technique [0002] figure 1 It is a structural schematic diagram of a capacitor voltage transformer (CVT, Capacitor Voltage Transformers) with a voltage level above 110kV, and the capacitor voltage transformer includes a capacitor voltage divider and an electromagnetic unit. The capacitive voltage divider usually includes a plurality of capacitor units connected in series, figure 1 The shown capacitive voltage divider includes four capacitor units connected in series, that is, capacitor unit C11, capacitor unit C12, capacitor unit C13 and capacitor unit C14 in series, with the primary side high-voltage lead-out line of the intermediate transformer T as the boundary, capacitor unit C11, The capacitor unit C12 and the capacitor unit C13 form a hi...

AI Technical Summary

Problems solved by technology

[0006] What the present invention is to solve is the problem of low accuracy of the dielectric loss value and capacitance of the capacitance of the bottom section of the capacitor voltage transformer.

Images