变压器升高座区域电弧故障与压力特性研究

Research on Pressure Characteristics of AC Turret on Arc Fault

变压器是特高压输电系统中的重要设备,变压器油箱内电弧放电故障引起的压强陡升将引起变压器燃爆事故,严重威胁电力系统的安全稳定运行。目前,尚缺乏针对高电压、大容量变压器升高座区域的电弧放电故障试验研究,燃爆过程不明晰,变压器防爆性能提升受到限制。通过搭建变压器网侧升高座区域油箱内的电弧放电故障真型模拟试验平台,进行大电流、高爆燃容量模拟短路试验,实现了对电弧放电故障后箱体内部压力上升过程和传递特性的测试试验;通过收集升高座筒壁上不同点位压强数据,得到不同燃弧能量下升高座内部压强时域变化曲线,分析电弧能量、电流与压力的关系,以及升高座、油箱及出线装置等结构对压力传递特性的影响过程。试验结果表明,电弧能量与电弧电流是影响升高座内升压的重要因素,电流从20kA增加至40kA时,筒壁上压强峰值将从0.79MPa增加至1.17MPa;同时,压力释放装置对于防止燃爆事故发生非常关键。试验研究初步阐明了变压器类设备油箱内部短路故障压力产生与传递的物理机制,对变压器防爆设计具有重要的指导意义。

A transformer is a critical piece of equipment in UHV power transmission system. However, the sudden pressure rise caused by arc fault of a transformer may make the oil tank explode, which seriously threatens the safe and stable operation of power system. There is still a lack of experimental research on arc fault in high voltage and large capacity transformer turret, the explosion process is not clear, and the improvement of transformer explosion-proof design is limited. In this paper, by building a simulation test platform of short circuit fault in the oil tank and the turret on AC side of the transformer, the simulation short circuit test of large current and high deflagration capacity was carried out, and the test of the internal pressure rise process of the tank after the arc fault was realized. By collecting the pressure data of different points on the wall of the turret, the time-domain curves of the internal pressure of the turret under different arc fault conditions were obtained. The relationship between arc energy, current and pressure has been analyzed and explored, and the influence of the turret, oil tank and outlet device on pressure transmission characteristics was analyzed. The results show that the arc energy and arc current are the important factors affecting the pressure rise in the turret. When the current increased from 20 kA to 40 kA, the peak pressure on wall would increase from 0.79 MPa to 1.17 MPa. The pressure relief device is of great significance to prevent the occurrence of explosions. The physical mechanism of generation and transmission of pressure caused by arc fault in oil tank has been expounded, which is of great significance to transformer explosion-proof design.