交流和直流电压下纤维和金属颗粒对天然酯击穿特性的影响差异研究

Influence Difference of Fiber and Metal Particles on Breakdown Characteristics of Natural Ester Under AC and DC Voltages

鉴于绝缘油中存在杂质颗粒是油品绝缘性能劣化的主要原因之一,为更好地推广应用天然酯及管控天然酯油品质量,进行了交流和直流电压下纤维和金属颗粒对天然酯击穿特性的影响差异研究,对含纤维和金属铜颗粒的天然酯分别在有无交流和直流预压2种加压情况下的击穿场强进行了测试,运用两参数Weibull分布模型分析了交流和直流电压下的击穿数据,并记录了油品击穿过程中的颗粒积聚形态。研究表明:随着天然酯中纤维或金属颗粒浓度的增加,天然酯的交流和直流击穿电压均呈现线性下降规律;与交流电压作用相比,天然酯的直流击穿电压随颗粒浓度的增加表现出更大的下降幅度;无论在交流还是直流电压作用下,含金属铜颗粒的天然酯均比含纤维颗粒的油品表现出更低的击穿强度;直流预压模式下含纤维和金属铜颗粒天然酯在击穿过程中存在明显的颗粒积聚成桥现象;通过对比交流和直流电压下有无预压2种模式下的击穿强度变化幅度,表明颗粒积聚成桥是导致天然酯的直流预压击穿强度比无预压情况下呈现更大下降幅度的原因。

The presence of impurity particles in insulating oil is one of the main reasons for the deterioration of insulation performance.In order to promote the application of natural ester and control the quality of natural ester oil,the effects of fiber and metal particles on the breakdown characteristics of natural ester under AC and DC voltages were studied.The two-parameter Weibull distribution model was used to analyze the breakdown data under AC and DC voltages,and the particle accumulation patterns in the process of oil breakdown were recorded.The results show that the AC and DC breakdown voltages of natural ester decrease linearly with the increase of the concentration of fibers or metal particles in natural ester.The DC breakdown voltage of natural ester decreases more significantly with the increase of the concentration of fibers or metal particles than with the increase of AC voltage.Natural ester containing copper particles exhibits a lower breakdown strength than oil containing fiber particles under AC or DC voltages.The natural ester containing particles shows a particle accumulation phenomenon in the breakdown process under DC preloading pattern.By comparing the breakdown strength of natural ester under AC and DC voltage,it is shown that the formation of bridging particles is the reason that the breakdown strength of natural ester under DC preloading decreases greatly compared with that in the absence of DC voltage.