内蒙古电网变压器抗短路能力核算与评估

为进一步减少变压器损坏事故,对内蒙古电网内变压器抗短路能力开展核算与评估。对变压器的短路过程建模,分析短路发生时绕组受到的电动力与短路电流的关系,通过修正制造厂家承诺的短路电流限值及统计基于故障案例的变压器短路电流限值两种方式,建立变压器可承受短路电流限值的样本数据库。依据抗短路能力管控平台和国网变压器抗短路中心开展评估过程,提出裕度系数概念,以量化抗短路能力改造的紧迫程度,并通过返厂解体和诊断试验验证抗短路能力评估结果,最后提出治理措施,以提高变压器的抗短路能力,保证电网的安全稳定运行。

Calculation and Evaluation of Short Circuit Resistance of Transformers in Inner Mongolia Power Grid

It is one of the main factors affecting the safe operation of the transformer that the transformer is damaged due to the lack of short circuit resistance after suffering from external short circuit impact.The short circuit resistance of transformer is calculated and evaluated in order to further reduce the damage accident of transformer.This paper models the short circuit process of transformer,analyzes the relationship between electrodynamic force of the winding and short circuit current when the short circuit occurs.By correcting short circuit current limit promised by the manufacturer,making statistics of short circuit current limit of transformer based on fault cases,the paper establishes a sample database of short circuit current limit of transformer.Relying on the short circuit resistance of transformers management and control platform and the center of short circuit resistance of transformers of state grid,the assessment process is carried out,and the concept of margin coefficient is proposed to quantify the urgency of improving short circuit resistance,and the assessment results of short circuit resistance are verified through the disassembly and diagnostic test.Finally,the governance measures are proposed to improve the short circuit resistance of the transformer and ensure the safe and stable operation of the power grid.