交流特高压变电站站用变保护技术方案

特高压交流变电站站用电系统通常采用2级降压的方式,2级串联变压器的主保护差动需引接110 kV和380 V侧的CT电流。在低压侧故障时,低压侧电流有几十千安培,而折算到高压侧仅几百安培,由于两侧电流数据相差较大,给站用变的CT选型及站用变保护的配置、原理、整定带来一些问题。通过研究"皖电东送"特高压工程的淮南变电站低压侧设备配置方案和接线方式,结合实际工程情况及设备参数,分析了特高压交流变电站站用变保护的特殊问题。提出采用一套保护装置中配置双套电流转换插件及两套差动保护、后备保护的技术方案,并建立动模系统验证了该原理方案的可行性。

Protection of station transformer of UHV AC substation station technology solutions

UHV AC substation auxiliary power system usually adopts two-stage step-down approach, and level 2 series transformer differential protection needs to be led by the CT of 110 kV and 380 V side current. When low voltage side failure occurs, the low voltage side current dozens thousand amperes, converting it to the high side, it is only a few hundred amperes. Because of the large difference on both sides of the current data, it brings some problems on CT model selection and configuration, principle, and setting of station transformer protection. Through the study of the configuration and connection mode of low voltage side of 1000 kV UHV Huainan substation equipment, combined with the actual engineering conditions and equipment parameters, this paper analyzes the UHV AC substation station with transformer protection special problems, puts forward the technology solution that a set of protection device is configured in the double set of current conversion module and two sets of differential protection and backup protection, and establishes a dynamic model system to verify the feasibility of this principle scheme.