一种防止母联备自投动作造成过负荷的闭锁逻辑

为避免高峰负荷时母联备自投动作可能造成变压器严重过载,提出一种计算变压器各侧开关电流之和的闭锁逻辑:开关电流之和大于备用变压器额定电流一定倍数时,对备自投装置实施闭锁。分析了此闭锁逻辑在110kV变电站不同变压器容量配置,不同一次接线方式等情况下的实际运用,针对CT变比不同的情况,提出了将采集电流在备自投逻辑中折算为一次电流进行相加或者引入CT变比调整系数两种解决方案,并对闭锁电流值的整定给出建议值。此闭锁逻辑对负荷进行了定量处理,且易于在各厂家、各型号备自投装置中实现,具有一定的实用价值。

The Application of Latching Logic to Prevent Overload Caused by Bus-tie Automatic Switching Action

In order to avoid the serious overload of transformer in peak load caused by bus-tie automatic switching action,a latching logic to calculate the sum of switch currents flowing in each side of the transformer is presented.When the sum of switch current is certain times bigger than rated current of backup transformer,the bus-tie automatic switcher is latched.The application situation of this latching logic to 110kV substation with different transformer capacity configuration and different connection mode is analyzed.Two kinds of schemes,the sum of sampled current that is converted to primary current in automatic switching logic and ratio adjusting coefficient introduced in CT,are proposed as to different ratio of CT.The suggestion of the setting of latching current value is also given.This latching logic can process load quantitatively,and is easily applied to automatic switching devices for each type and each manufacturer,which has certain practical value.