电力变压器振荡型雷电冲击耐压试验及局部放电检测技术

scillating Lightning Impulse Voltage Withstand Test and Partial Discharge Detection Technology for Power Transformers

振荡型雷电冲击电压产生效率高,被IEC60060-3标准推荐作为电力变压器现场雷电冲击耐压试验波形。该文研究了振荡型雷电冲击的产生原理,明确了试验回路中波前电阻、波尾电阻和调波电感等电路参数对振荡型雷电冲击电压波形参数的影响。基于粒子群算法,提出了振荡型雷电冲击调波优化算法,通过测量变压器频响曲线获得阻抗参数,提取冲击发生器和试验回路参数,快速得到最优的调波电路参数,从而获得满足标准要求的振荡型雷电冲击电压波形。在220 kV变压器开展了振荡型雷电冲击耐压试验,所提波形优化方法仅在运行1 min、迭代200次之后收敛到最优解,节省了原本需要1h的波形调试工作。试验结果表明,在振荡型雷电冲击试验同时开展局部放电测量,可以实现对变压器故障的早期诊断和绝缘状态的全面评估。

Oscillating lightning impulse(OLI)voltage is recommended by IEC60060-3 as the field test waveform of power transformers due to its high generation efficiency.In this paper,the generation method of OLI is studied,and the influence of circuit parameters such as wave-front resistance,wave-tail resistance and additional inductance on the OLI waveform parameters is clarified.An optimization algorithm for OLI waveform adjustment is proposed based on the par-ticle swarm optimization(PSO)algorithm.The impedance parameters are obtained by measuring the frequency response analysis(FRA)signature of the transformer,the parameters of the impulse generator and the test circuit are acquired,and the optimal circuit parameters are calculated,so that the OLI waveform which meets the standard requirements can be generated.The OLI voltage withstand test is carried out on a 220 kV transformer,and the proposed method converges to the optimal solution after 200 iterations within 1 minute,saving an hour of waveform adjusting work.The test results show that the early diagnosis of transformer fault and the comprehensive evaluation of insulation state can be realized by detecting partial discharge during the OLI voltage withstand test.