浅析Unitrol 5000励磁系统PT断线逻辑缺陷及改进方法

Analysis of PT Disconnection Logic Defect and Improvement Method of Unitrol 5000 Excitation System

本文对大型火力发电厂普遍采用的ABB Unitrol 5000静态励磁调节控制系统构成及优缺点进行了简单介绍。并结合某火力发电厂发生的一次励磁系统电压异常波动事件进行分析,得出Unitrol 5000静态励磁调节控制系统在发电机机端PT一次侧保险熔丝非完全熔断、二次接线松动时,可能会造成励磁电压调节异常,严重时有可能造成设备误强磁、保护误动。通过对Unitrol 5000静态励磁调节控制系统PT断线逻辑进行分析探讨,制定PT断线逻辑改进措施,对Unitrol 5000静态励磁调节控制系统安全可靠运行具有重要意义。

In this paper,the structure,advantages and disadvantages of ABB Unitrol 5000 static excitation regulation and control system widely used in large-scale thermal power plants are briefly introduced.Based on the analysis of an abnormal voltage fluctuation event of the excitation system in a thermal power plant,it is concluded that the Unitrol 5000 static excitation regulation and control system may cause abnormal excitation voltage regulation when the fuse on one side of the PT of the generator is not completely fused and the secondary connection is loose.In serious cases,it may cause equipment misexcitation and protection misoperation.Through analyzing and discussing the PT disconnection logic of Unitrol 5000 static excitation regulation and control system,the improvement measures of PT disconnection logic are formulated,which is of great significance for the safe and reliable operation of Unitrol 5000 static excitation regulation and control system.