大型电力变压器内绕组辐向抗短路能力评估

随着电网容量和电压等级的提高，大型电力变压器短路导致的恶性事故不断增加，这种情况已直接威胁电网安全运行。通过对大型电力变压器漏磁通及短路电动力分析，指出变压器内绕组的辐向失稳已成为绕组耐受短路的首要问题。研究了电力变压器内绕组辐向电动力计算和抗短路能力校核评估方法，并给出了变压器绕组线饼的临界失稳强度和抗短路能力评估计算流程。最后通过具体实例并依据四种改进措施进行对比分析，提出提高变压器抗短路能力具体的改进措施。

An assessment of ability to withstand radial short circuit of large power transformer inner windings

With the increasing of power grid capacity and voltage level, the serious accidents caused by a large power transformer short-circuit are increased, and this situation has a direct threat to the safe operation of the grid. Through analysis of the large power transformer leakage flux and short-circuit electromagnetic forces, the radial mechanical instability of transformer inner winding is pointed out, then a radial electromagnetic force calculating and an assessment of ability to withstand short-circuit on inner windings are researched. Moreover, the critical destabilization strength of winding pies and assessment process of the ability to withstand short-circuit for large power transformers are given. At last, the improvement measures to increasing the ability to withstand short-circuit for transformers are proposed based on case studies and four kinds of comparative analysis.