Optimization of grading ring design for a new UHV equipotential shielding capacitor voltage transformer

Xie, Le; Zheng, Jian; Li, Zhiqi; Dong, Wei; Zha, Kun Peng; Tang, Guangfu

doi:10.1109/ceidp.2011.6232764

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…e Capacitor Voltage Transformer (CVT) has high dielectric strength, fast transient response, wide dynamic range, low power consumption, and nonferromagnetic resonance with power systems. It also can reduce the head steepness of lightning shock and be used as a coupling capacitor for the power carrier communication [1][2][3][4]. us, it is widely applied in power systems from 35 to 1000 kV.…”

Section: Introductionmentioning

confidence: 99%

“…For the CVT applied in the 750 kV voltage level and above, the stray capacitance of the CVT to the high-voltage terminal increases the VDR of the CVT more than 0.1% [21]. Installation of a grading ring for a new UHV equipotential shielding CVT can improve the voltage distribution and compensate for the adverse effect caused by stray capacitance [3]. Furthermore, the rated bulk capacitances of this UHV CVT are derived under the interference of stray capacitances [7].…”

Section: Introductionmentioning

confidence: 99%

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Studying the Effect of Stray Capacitance on the Measurement Accuracy of the CVT Based on the Boundary Element Method

et al. 2021

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The capacitive voltage transformer (CVT) is a special measuring and protecting device, which is commonly applied in high-voltage power systems. Its measurement accuracy is affected seriously by the stray capacitances of the capacitance voltage divider (CVD) to ground and other charged parts. In this study, based on the boundary element method, a mathematical model was established firstly to calculate the stray capacitance. Then, the voltage distribution of the CVD was obtained by the CVD’s equivalent circuit model. Next, the effect of stray capacitance on the voltage distribution and the voltage difference ratio (VDR) of CVD was analysed in detail. We finally designed three types of shield and optimized their structure parameters to reduce VDR. The results indicated that the average deviation rate between calculated and experimental measured voltages is only 0.015%; that is to say, the method has high calculation precision. The stray capacitance of the CVD to ground is far larger than that of the CVD to the high-voltage terminal. It results in the inhomogeneous distribution of voltage and the increase of VDR. For the test CVT, its VDR exceeds the requirement of class 0.2. Among all of the three types of shield, the C type reduced the VDR of the test CVT the most. After optimizing the structure parameters of C-type shield, the VDR is further reduced to 0.08%. It is not only in accord with the requirement of class 0.2 but also has an adequate margin.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%