新型大容量调相机组非电量保护迁移改造相关问题分析及解决措施

Analysis on Relevant Issues and Solutions for Relocation and Transformation of the New-type Large-capacity Synchronous Condensers with Non-electric Quantity Protection

随着特高压大电网的建设,国内新建了多台300 Mva r大型调相机组。这些机组所配备的非电量保护信号首先经过DCS系统进行三取二逻辑判断,并输出三路跳闸出口至非电量保护,然后再经过三取二装置出口跳闸,信号链路复杂,误动、误判的风险高。为了提高保护动作的可靠性和正确性,需要将非电量保护与DCS系统完全解耦,消除DCS的冗余环节带来的不可靠风险。在开展该项工作过程中,需要引入转换装置将模拟量信号转换为数字量信号送至非电量保护屏。文章解决了转换装置故障造成的保护拒动问题、轴瓦温升速率异常和定子铁心温升速率异常造成的保护误动问题,并介绍了非电量保护跳闸事件、跳闸首出信号以及转换装置监视优化方法,还提出了空冷型调相机组外冷水断水保护逻辑优化策略。通过优化保护逻辑配置、提升装置供电可靠性和完善设备状态信息监视等方式有效提升了调相机设备可靠性。

With the building-up of the ultra-high volt-age power grid,multiple 300 Mvar large-size condenser units have been newly built in China.The non-electric protection signals equipped with these unitsfirst undergo a two out of three logic judgment through the DCS system,and then,these signals output to the non-electric protec-tion through a three way trip outlet,afterwards,they trip through the two out of three device outlet,resulting in a complex signal link that increases the risk of mis-operation and misjudgment.In order to improve reliability and correctness of the protection actions,it is necessary to completely decouple the non-electric protection from the DCS system and eliminate the unreliable risks caused by redundant links in the DCS.In the process of carrying out this work,it is necessary to introduce a conversion device to turn the analog signals into digital signals and send them to the non-electric protection screen.The article solves the is-sues of protection rejection caused by the conversion device failures and protection mis-operation caused by abnormal temperature rise rate of bearing shells and stator iron core,introduce such issues as the tripping events,trippingfirst output signals and conversion device monitoring in the non-electric protection,and puts forward the strategy of logic optimization for the external cold water cut-off pro-tection of the air-cooled condenser units.Reliability of the condenser equipment is effectively improved by means of optimizing the protection logic configuration and reliabil-ity of device power supply as well as improvement of the equipment status information monitoring.