早期的保护方法主要集中在使用通信通道在保护设备(PD)之间传输跳闸信号,在通信失败的情况下没有提供解决方案。因此,本文介绍了一种双层保护系统,以确保针对配电系统(DS)中的故障事件的安全保护,特别是在通信故障的情况下。初始层使用总谐波失真(THD),振幅电压的估计,和零序电网电压分量,作为故障传感器,制定基于有限状态机(FSM)的自适应算法,用于检测和隔离电网内的故障。该层主要依靠通信协议进行有效协调。二阶广义积分器(SOGI)加速了估计变量的推导,以最小的计算开销确保快速检测。第二层在故障事件期间使用电网电压的正序分量和负序分量的行为来定位和隔离这些故障。如果第一层暴露通信故障,第二层将自动激活,以确保其运行时的安全保护,使用保护装置(PD)的本地信息,无需通信信道在PD之间传输跳闸信号。所提出的保护系统已使用MATLAB/Simulink进行了仿真评估,并提供了考虑IEEE9总线标准径向系统的实验结果。获得的结果证实了系统识别和隔离不同类型故障的能力,不同的条件,以及对网格配置的修改。结果表明初始THD基层的良好行为,在所有检查的场景中,快速时间响应范围从6到8.5ms。相比之下,基于序列的层表现出大约150毫秒的保护时间响应,使其在通信失败的情况下成为可行的备份选项。
Earlier protection methods mainly focused on using communication channels to transmit trip signals between the protective devices (PDs), with no solutions provided in the case of communication failure. Therefore, this paper introduces a dual-layer protection system to ensure secure protection against fault events in the Distribution Systems (DSs), particularly in light of communication failures. The initial layer uses the Total Harmonic Distortion (THD), the estimates of the amplitude voltages, and the zero-sequence grid voltage components, functioning as a fault sensor, to formulate an adaptive algorithm based on a Finite State Machine (FSM) for the detection and isolation of faults within the grid. This layer primarily relies on communication protocols for effective coordination. A Second-Order Generalized Integrator (SOGI) expedites the derivation of the estimated variables, ensuring fast detection with minimal computational overhead. The second layer uses the behavior of the positive- and negative-sequence components of the grid voltages during fault events to locate and isolate these faults. In the event that the first layer exposes a communication failure, the second layer will automatically be activated to ensure secure protection as it operates, using the local information of the Protective devices (PDs), without the need for communication channels to transmit trip signals between the PDs. The proposed protection system has been assessed using simulations with MATLAB/Simulink and providing experimental results considering an IEEE 9-bus standard radial system. The obtained results confirm the capability of the system for identifying and isolating different types of faults, varying conditions, and modifications to the grid configuration. The results show good behavior of the initial THD-based layer, with fast time responses ranging from 6 to 8.5 ms in all the examined scenarios. In contrast, the sequence-based layer exhibits a protection time response of approximately 150 ms, making it a viable backup option in the event of a communication failure.