李家峡水电站4T主变压器冷却控制系统的改造

为提高李家峡水电站设备自动化水平,满足电厂“无人值班,少人值守”的需要,李家峡水电站对4T主变冷却系统进行了技术改造.文章根据电厂实际情况,从自动控制原理入手,分析了4T主变压器冷却控制系统改造的可行性,通过对其冷却系统进行了PLC方式和常规方式双重控制,实现了主变冷却系统保护（主变冷却水中断保护、主变冷却器全停保护）的双重化配置,完成了主变冷却控制系统保护回路的改造,保证了机组健康、稳定地运行.

Transformation of the 4T Main Transformer Cooling Control System of Lijiaxia Hydropower Station

In order to improve equipment automation level of Liji ax ia hydropower station and meet the requirement of "unattended and less on duty", the station has made some transformantion on the cooling system of 4T main tran sformer. The paper analyses the feasibility of the transformation through automa tic control principle and combining with the practical situation of the station. Through carrying out the double control system(i.e.PLC and normal mode on the cooling system), the station realizes protection's duplex con figuration of the main transformer cooling system(the interruption protection of the cooling water and the whole stoppage of the cooler); completes the protecti on loop's transformation of the main transformer cooling control system, thus gu arantee the stable operation of the unit.