Temperature Segment Compensation Method of Dissipation Factor for Insulation Diagnosis in Converter Transformer Bushing

Quanmin Dai,Yinoon Zhang,Yanxia Liu,Zhiming Huang,Huidong Chen,Xin Yu

doi:10.1109/access.2022.3144077

Abstract

Temperature compensation occupies a significant function in the insulation condition evaluation of converter transformer bushings based on the Frequency Domain Spectroscopy (FDS), which could influence the accuracy of its insulation diagnosis. In order to accurately obtain the variation law of FDS at different temperature, a Resin Impregnated Paper (RIP) insulation bushing for converter transformer was designed by the equivalence of maximum electric field, coaxial cylinder structure and RIP materials. The increment law of dielectric parameters both dissipation factor and capacitance at wideband frequency (1mHz ~ 10kHz) was measured for a quality RIP insulation samples at the temperature from 30°C to 100°C. 1) Under the uniform temperature, it was found that the value of dissipation factor was rising with the frequency from 10 Hz to 0.001Hz, while the tendency was reversed at the frequency from 100Hz to10kHz. 2) The minimum value of tan <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\delta $ </tex-math></inline-formula> from 0.001Hz to 10kHz could be driven to higher frequency moving (10Hz to 10kHz) by the action of temperature rising 30°C to 100°C.3) The effect of temperature on the lower frequency 0.001Hz ~ 1Hz tan <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\delta $ </tex-math></inline-formula> of RIP insulation closely conformed to the index law of Arrhenius equation, while it was in accordance with the linear decrease at higher frequency 1kHz ~ 10kHz. The effect of temperature on dissipation factor could be eliminated by curve segment shifting based the experiment equation, which it at 0.001Hz dissipation factor could be eliminated by curve shifting based the index equation originated Arrhenius equation. The method is beneficial to eliminate the influence of temperature on the dielectric spectroscopy test results, and then to eliminate the influence of temperature on the dielectric spectroscopy diagnosis of RIP bushings.

Highlights

As the most complex, expensive and enormous equipment in the HVDC transmission system, the quality of insulation in converter transformer has become a constraint critical factor of the construction and operation of the current transmission project [1], [2]
The resin-impregnated paper (RIP) bushing in the converter transformer is the key equipment for the valve side winding to external connection in ultra-high voltage (UHV) converter stations [3], [4]
3) The effect of temperature on the lower frequency 0.001Hz ∼ 1Hz tanδ of RIP insulation closely conformed to the index law of Arrhenius equation, while it was in accordance with the linear decrease at higher frequency 1kHz ∼ 10kHz

Summary

Introduction

Expensive and enormous equipment in the HVDC transmission system, the quality of insulation in converter transformer has become a constraint critical factor of the construction and operation of the current transmission project [1], [2]. INDEX TERMS Converter transformer, resin-impregnated paper insulation, frequency domain spectroscopy (FDS), temperature, dissipation factor, fault diagnosis. Frequency domain spectroscopy (FDS) is an important method for detecting the insulation status of resin-impregnated paper insulation in converter transformers.

Results

Conclusion