Surface Potential Decay and DC Conductivity Characteristics of Epoxy Composites

doi:10.11985/2018.11.008

Abstract

Abstract:

Epoxy/Al₂O₃ composites are usually used to cast GIL insulators. Under the effects of DC voltage and temperature rise caused by load, the charges are prone to accumulate on the insulator surface and thus cause electric field distortion, which may in turn cause surface flashover. In order to explore the effect of non-linear ZnO fillers on the dielectric properties of Epoxy/Al₂O₃/ZnO nonlinear composites, the surface potential decay of epoxy composites with different ZnO contents under DC voltage was measured. The effects of different temperatures on the surface charge characteristics were analyzed and the nonlinear conductivities based on charge dissipation was obtained. The results show that ZnO particles can significantly promote the surface potential degradation of epoxy composites under DC voltage. With the increase of temperature, the carrier mobility increases and the surface charge dissipates faster. When the ZnO content exceeds a certain threshold, the conductivity shows a nonlinear behavior in the high field, which suppresses the surface charge accumulation of the epoxy composite. The results provide references for the application of nonlinear conductivity materials in the control of surface charge characteristics of insulators in DC gas insulated lines.

Key words: Gas insulated line, epoxy insulator, operating temperature, surface charge, nonlinear conductivity

CLC Number:

TM85

Ran Zhaoyu,Du Boxue,Li Jin,Liang Hucheng,Zhang Cheng. Surface Potential Decay and DC Conductivity Characteristics of Epoxy Composites[J]. Journal of Electrical Engineering, 2018, 13(11): 65-70.

Figures/Tables 8

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直流电压 /kV	表面电荷衰减速率/(V/s)
直流电压 /kV	ZnO含量 12.5%试样	ZnO含量 25%试样	ZnO含量 37.5%试样	ZnO含量 50.0%试样
4	0.70	6.30	13.77	15.90
5	2.08	5.60	20.92	27.55
6	2.42	9.42	24.37	30.68

实验条件	载流子迁移率 /(m²·(s·V)^-1)	陷阱能级 /eV	陷阱密度 /(m^-3·(eV)^-1)
温度30℃,直流电压4kV	1.518×10^-12	0.821	1.174×10²⁰
温度60℃,直流电压4kV	1.987×10^-11	0.856	2.111×10²⁰
温度30℃,直流电压5kV	2.271×10^-12	0.815	1.728×10²⁰
温度60℃,直流电压5kV	2.953×10^-11	0.863	4.296×10²⁰