尖刺放电缺陷的SF_(6)光-电特性分析

Optical-electrical properties of SF_(6) under 50 Hz AC corona discharge

局部放电导致的绝缘缺陷是SF_(6)气体绝缘电气设备运行中出现最多的故障之一。为此,本文在模拟尖刺放电缺陷的基础上,利用光谱仪、光电倍增管和特高频传感器等对放电过程中SF_(6)的发射光谱、时域光脉冲、特高频等信号进行了检测,分析了SF_(6)在放电条件下的光学-电学联合特性。试验结果表明:SF_(6)的特征谱线主要在482~485 nm、 492 nm、 502~507 nm、 574~577 nm和629 nm波长处;随着电场强度的增大,502~507 nm波长处的特征谱峰出现了斯托克斯增宽。根据PRPD谱图,特高频信号主要集中在负半周期270°附近,随着施加电压的增大,脉冲数、幅值及分布区间宽度均逐渐增大。对于光脉冲信号,放电开始阶段,光学信号主要集中在正半周90°和负半周270°附近;当施加电压进一步增大时,信号同时出现在正、负半周,信号幅值无明显变化,但信号脉冲数的密度明显增大。

The insulation defect caused by partial discharge is one of the most frequent faults of SF_(6)gas-insulated electrical equipment.To understand the optical-electrical characteristics of partial discharge,this paper carried out a series of experiments through a needle-plate electrode to simulate the corona discharge,and detects the emission spectrum,time-domain optical pulse,and ultra-high frequency(UHF)signals by a spectrometer,a photomultiplier,and a UHF sensor,respectively.The results show that the characteristic spectra of SF_(6)under the corona discharge are mainly at the wavelength of 482~485 nm,492 nm,502~507 nm,574~577 nm,and 629 nm.As the electric field strength increases,stokes broadening occurs in the characteristic spectrum of 502~507 nm.According to the phase-resolved partial discharge(PRPD)analysis at the partial discharge inception stage,UHF signals are mainly distributed around 270°of the negative half period,and optical pulse signals are distributed around 90°and 270°.As the applied voltage increases,the number and density of UHF and optical pulse signals increase.The amplitude of UHF gradually increases as the applied voltage increases,but the amplitude of optical pulse signals seems less affected by the applied voltage.