Abstract Inclusion of distributed energy resources based integrated microgrid (IMG) into emergency station blackout (SBO) (EM-SBO) power system of nuclear power plant (NPP) has complicated its existing protection scheme due to varying system fault level with bidirectional flow of power. During SBO in NPP, it is of topmost priority to safeguard the reactor through EM-SBO supply. However, if any severe fault occurs, it may lead to complete collapse of the safety power supply in the NPP. So, availability of this tiny power system is most important as compared to the tripping of reactor safety of the NPP. In this paper, a 460 MWe NPP station has been considered to implement IMG into its EM-SBO power system and focuses on its overcurrent protection coordination scheme as a case study. The combined fuse and numerical relays inter-linked with digital logic-based adaptive overcurrent protection (AOP) scheme has been proposed after load flow analysis and calculating short circuit fault level through ETAP software. The sensitivity, the selectivity and the speed of the protection scheme have been evaluated in different network configurations like on-grid, semi-islanding and islanding mode of operation of IMG. Finally, it is proposed that the protection schemes vary from case-to-case basis leading to necessity of communication among the relays. So, an advanced AOP scheme with digital logic linked through peer-to-peer Hi-speed communication (IEC 61,850 confirmed GOOSE technology) has been proposed to resolve the protection issue of the modern NPPs operated through IMG.

中文翻译：

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适用于集成微电网运行的核电站停电供电的自适应过流保护方案

摘要 将基于分布式能源的集成微电网 (IMG) 纳入核电站 (NPP) 应急站停电 (SBO) (EM-SBO) 电力系统，由于电力双向流动的系统故障级别不同，其现有保护方案变得复杂。 . 在核电厂 SBO 期间，通过 EM-SBO 供应保护反应堆是重中之重。但是，如果发生严重故障，则可能导致核电厂安全电源完全崩溃。因此，与核电站反应堆安全性的跳闸相比，这种微型电力系统的可用性最为重要。在本文中，一个 460 MWe 的核电站被考虑在其 EM-SBO 电力系统中实施 IMG，并重点研究其过流保护协调方案作为案例研究。在潮流分析和通过 ETAP 软件计算短路故障水平后，提出了与基于数字逻辑的自适应过流保护 (AOP) 方案互连的熔断器和数字继电器组合。保护方案的灵敏度、选择性和速度已在 IMG 的并网、半孤岛和孤岛运行模式等不同网络配置中进行了评估。最后，建议保护方案因情况而异，导致继电器之间需要通信。因此，已经提出了一种通过对等高速通信（IEC 61,850 确认的 GOOSE 技术）链接数字逻辑的先进 AOP 方案，以解决通过 IMG 运行的现代核电厂的保护问题。