田湾核电VVER型机组厂用电系统国产化进程中若干问题分析

Analysis of Several Problems in the Process of Localization of the Power System of Tianwan Nuclear Power VVER Plant

田湾一期工程使用全套的俄罗斯技术和设备,其二次保护系统及自动装置仍普遍采用电磁式,近年来已逐步更新换代为微机保护。田湾二期工程在设计思路上沿袭了一期的设计思路,相对于设备的不断更新,原有的设计思路也存在着诸多需要重新思考分析的地方。针对田湾核电一期、二期先后两次厂用电源切换失败事件和6 kV母线低电压保护误动触发机组降功率停堆事件,从设计思路本身出发,对原有设计提出改进建议,并就发电机励磁变冷却风机系统薄弱环节提出改进思路。

The first phase of Tianwan project used a complete set of Russian technology and equipment,and its secondary protection system and automatic devices are still generally electromagnetic.In recent years,they have been gradually upgraded to microcomputer protection.The Tianwan Phase II project followed the design ideas of the first phase in terms of design ideas.Compared with the continuous updating of equipment,the original design ideas also have many places that need to be rethought and analyzed.The first and second phases of Tianwan Nuclear Power had two switching failure events for the power supply of the plant,and at the same time,the low-voltage protection of the 6 kV bus bar was mis activated and triggered the unit power reduction and shutdown event.In view of this problem,the analysis is carried out from the design idea itself,the original design is improved,and the weak link of the generator excitation variable cooling fan system is put forward.