分裂绕组高阻抗电力变压器短路特性研究

Research on short-circuit characteristics of split-winding high impedance power transformer

文中对比了分裂绕组、高压内置以及串抗结构三种高阻抗电力变压器的优缺点,通过有限元分析得到了分裂绕组高阻抗电力变压器高中短路和中低短路的漏磁分布,对变压器进行了承受短路能力判断,并通过短路试验论证了研究结果的正确性。仿真与试验数据表明,分裂绕组高阻抗变压器虽然存在结构尺寸偏大,极限分接阻抗变化大等不利因素,但此结构相较传统变压器具有更强的承受短路能力。同时,试验后中低阻抗变化率0.49%大于高中工况0.15%,说明即使采用了高阻抗结构,低压绕组承受短路能力依然弱于高、中绕组,在实际应用中应重点关注。

This paper firstly compares the advantages and disadvantages of three kinds of high impedance power transformers,namely split winding,high voltage built-in and series resistance structure.The magnetic leakage distribution of high and low short-circuit and medium short-circuit in high impedance power transformer with split winding is obtained by finite element analysis.The short-circuit ability of the transformer is judged,and the correctness of the research results is proved by short-circuit test.The simulation and test data show that the high-impedance transformer with split winding has a stronger short-circuit resistance than the traditional transformer,although it has some disadvantages such as larger structure size and larger limit tapping impedance change.At the same time,after the test,the change rate of low and medium impedance 0.49%is greater than that of high and medium conditions 0.15%,indicating that even if the high-impedance structure is adopted,the short-circuit resistance of the low-voltage winding is still weaker than that of the high and medium winding,which should be paid attention to in practical applications.