考虑微电网安全备用的核电站自适应过电流保护方案

Adaptive Overcurrent Protection Scheme for Nuclear Power Plant Considering Safety Reserve of Microgrid

针对目前核电站应急停堆供电系统(Emergency station blackout,EM-SBO)安全电源系统无法满足可靠性的问题,将微电网纳入EM-SBO安全备用电源体系,然而微电网运行方式复杂化,潮流方向不确定,出力波动性大,使得现有过电流保护动作阈值难以整定,容易引起误动作,进而无法有效保障核电厂安全运行。针对该问题,本文提出了考虑微电网安全备用的核电站自适应过电流保护(Adaptive overcurrent protection,AOP)方案;本方案包含多类型继电器和熔断器的协调配置。首先给出了集成微电网(Integrated microgrid,IMG)接入EM-SBO的系统结构,阐明IMG与传统EM-SBO电源的协调原则;然后,给出了继电器和熔断器的配置原则和协调方法;接着为了解决微电网接入引入的不确定性问题,提出了基于长短时记忆神经网络(Long short time memory neural network,LSTM)的继电器自适应整定方法,可以根据当前微电网运行模式和出力情况,自适应整定保护的继电特性。最后,基于ETAP软件进行仿真验证,证明本文保护方法在微电网不同运行模式下均具有较高的选择性、灵敏性和快速性。

Aiming at the problem that the current emergency station blackout(EM-SBO)cannot meet the reliability,brings the microgrid into the EM-SBO safety standby power supply system.However,the operation mode of the microgrid is complex,the direction of the power flow is uncertain,and the output fluctuation is large,which makes it difficult to set the action threshold of the existing overcurrent protection,easy to cause malfunction,and thus cannot effectively ensure the safe operation of the nuclear power plant.To solve this problem,this paper proposes an adaptive overcurrent protection(AOP)scheme for nuclear power plants considering the safety reserve of microgrid;The scheme includes coordinated configuration of multi type relays and fuses.Firstly,the system structure of img connecting to EM-SBO is given,and the coordination principle between Integrated microgrid(IMG)and traditional EM-SBO power supply is expounded;Then,the configuration principle and coordination method of relay and fuse are given;In order to solve the uncertainty with microgrid access into grid,a relay adaptive setting method based on long short time memory neural network(LSTM)is proposed,which can adaptively set the relay characteristics of protection according to the current microgrid operation mode and output.Finally,the simulation based on ETAP software proves that the proposed protection method has high selectivity,sensitivity and rapidity in different operation modes of microgrid.