Partial discharge measuring device and method of electrical tree growth process in crosslinked polyethylene (XLPE) cable insulation

Abstract

The invention provides a partial discharge measuring device and method of an electrical tree growth process in crosslinked polyethylene (XLPE) cable insulation. The device includes a laboratory vessel, a high voltage power supply, a microscopy digital camera system, and a partial discharge test system; the high voltage power supply includes a pressure regulator and a high voltage test transformer; one end of a coil of the high voltage test transformer is in series connection with a protection resistor; a coupling capacitor is connected in parallel between the other end of the protection resistor and the other end of the coil; a capacitor voltage divider is connected in parallel with the coupling capacitor; the partial discharge test system includes a detection impedance, an amplifier, and an industrial control computer with a built-in high-speed digital acquisition card, wherein the detection impedance and the amplifier are connected with a sample; the industrial control computer includes a high-speed double-channel digital acquisition card, and a partial discharge data acquisition, processing and discharge characteristic analysis unit.

Description

technical field [0001] The invention relates to a measuring system capable of continuously measuring the partial discharge in the growth process of electric dendrites in polymers, in particular to a measuring system capable of continuously measuring the partial discharge in the growth process of electric dendrites in cross-linked polyethylene cable insulation. Background technique [0002] Cross-linked polyethylene (XLPE) cables are widely used in urban power transmission due to their superior electrical, mechanical and thermal properties. With the rapid development of cities and modern industries, XLPE cables with high voltage levels above 110kV are widely used in cities in my country. There are more and more applications in the power grid. [0003] However, under the action of local high field strength, air gaps will form in the polymer insulation, and then due to the action of partial discharge, the air gaps gradually grow into filament-like corrosion channels and present ...

AI Technical Summary

Problems solved by technology

[0005] The general electrical dendrite experimental system usually separates the measurement of electrical dendrite growth and partial discharge from each other, or cannot continuously measure the partial discharge during the observation of dendrite growth: for example, Professor Zheng Xiaoquan published a paper titled "Crystalline State The influence of electrical tree branches in XLPE cable insulation" (Xiaoquan Zheng, George Chen. Propagation mechanism of electrical tree in XLPE cable insulation by investigating a double electrical tree structure. IEEE Trans. Dielec. Electr. Insul., Vol.15, No.3, pp.800-807, 2008), which observed electrical dendrites in XLPE cable insulation with different crystalline states at room temperature, but did not measure partial discharge during dendritic growth; for example: Professor Wu Kai published an article on Applied Physics in the UK (Kai Wu, Yasuo Suzuoki, Teruyoshi Mizutani. Model for partial discharges associated with treeing breakdown: I.PDs in tree channels. J. Phys. D: Appl. Phys. 33 (2000) 1197–1201.Printed in the UK), this article also measured the partial discharge while observing the branch growth process in real time, but it only measured the partial discharge of a single pulse, and did not achieve continuous measurement of partial discharge

[0006] However, for XLPE cables, the generation of electrical tree branches in the cable insulation is a complex process of electricity, heat, and internal mechanical stress of the material. The initiation time and tree shape of electrical tree branches are different under different applied voltages. Moreover, the growth rate of electrical tree branches is different at each growth stage, and the partial discharge accompanying the dendrite process has a great impact on the development of its dendrites. It is not enough to observe the growth process in real time or to measure the partial discharge intermittently.

At present, there is no complete system that can continuously measure the partial discharge generated during the growth of electric tree branches.

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