CAJ | 학술논문

换流变压器是直流输电系统的核心设备，其油纸复合绝缘结构的空间电荷特性复杂，工程实践表明其对绝缘放电的影响不可忽略，因此针对油纸复合绝缘开展空间电荷特性的研究对换流变绝缘结构设计和运行分析有指导意义。为此，应用电声脉冲（PEA）法研究了电场对双层油浸纸介质中空间电荷特性的影响以及界面处的空间电荷特性。指出在双层油浸纸的界面处将积聚负电荷，无论是极化还是去极化过程，双层油纸介质中的空间电荷的积聚和消散均较缓慢。在较高场强的作用下，阳极电荷注入过程的加强掩盖了阳极附近的电离过程。研究认为双层介质界面势垒是造成介质内部空间电荷运动缓慢的根本原因。而界面处负空间电荷的积聚则由势垒陷阱捕获和界面两侧场强差异导致电导差异两个过程共同决定。
환류변압기시직류수전계통적핵심설비，기유지복합절연결구적공간전하특성복잡，공정실천표명기대절연방전적영향불가홀략，인차침대유지복합절연개전공간전하특성적연구대환류변절연결구설계화운행분석유지도의의。위차，응용전성맥충（PEA）법연구료전장대쌍층유침지개질중공간전하특성적영향이급계면처적공간전하특성。지출재쌍층유침지적계면처장적취부전하，무론시겁화환시거겁화과정，쌍층유지개질중적공간전하적적취화소산균교완만。재교고장강적작용하，양겁전하주입과정적가강엄개료양겁부근적전리과정。연구인위쌍층개질계면세루시조성개질내부공간전하운동완만적근본원인。이계면처부공간전하적적취칙유세루함정포획화계면량측장강차이도치전도차이량개과정공동결정。
We investigated space charge distribution in a two-layer oil-paper insulation system using the pulsed electroacoustic （PEA） technique, and analyzed the effects of electric field and interface on space charge characteristics. The test results show that both interface and electric field affect the behavior of space charge. The interface between two oil-paper layers acts as a barrier to negative charge, as a result, negative charge accumulates adjacent to the interface. The space charge accumulation and dissipation in two-layer samples is slow whether it is in the process of polarization or depolarization. Under a higher electric field, the enhancement of the process of space charge injection at the anode covers the process of ionization near the anode. We believe that the potential barrier at the interface between two-layer dielectrics is the root cause of the slow motion of the space charge inside. While the accumulation of negative charge at the interface is decided by the capturing of barrier traps and the difference of conductivity between both sides of the interface , which is caused by the diversity of electric field inner each layer.