Power-system protection

About: Power-system protection is a research topic. Over the lifetime, 6353 publications have been published within this topic receiving 117961 citations.

Optimal Configuration of Interdependence Between Communication Network and Power Grid

Abstract: Smart grid is a cyber-physical system with interdependent power grid and communication network. Such interdependence make the smart grid fragile against cascading failures, where an initial failure in communication network may lead to further failures in power grid, and vice versa. We prevent such inter-network cascading failure by stopping an initial failure from propagating. This is achieved by providing a sufficient number of power-disjoint communication routes between power nodes and control center. The number of power-disjoint routes is a robustness metric. We aim to maximize robustness by configuring the interdependence relationship between power grid and communication networks. Such relationship indicates which power node supplies energy to which communication node, and which communication route is used to connect which power node to the control center. Following Menger's Theorem, we transform such configuration problem into a Maxflow problem and solve it using the simplex algorithm. We have evaluated the proposed method through extensive simulations. The results confirm the optimality and computational efficiency of the proposed method. The number of power-disjoint routes increases with an increase in the network size, but can never exceed the number of node-disjoint routes for a same network.

Planning of distribution feeder reconfiguration with protective device coordination

Abstract: An algorithm for planning distribution feeder reconfiguration that accounts for protective device coordination is presented. Distribution feeders are normally reconfigured with changing load patterns to achieve load balancing and loss reduction. To ensure that the protective devices are properly coordinated during feeder reconfigurations, the locations of the fuses for the distribution system under study are determined by using the proposed algorithm. A set of switchable regions within which switch operations are allowed for feeder reconfiguration is identified. Once the distribution system has been planned using the developed algorithm, the feeders can be reconfigured in real-time distribution system operation with all protective devices properly coordinated by changing the open/closed states of the switches in the switchable regions. The effectiveness of the approach is demonstrated by conducting feeder reconfiguration planning on a distribution network in the Taiwan power system. >

Impact of Inverter Based Resources on System Protection

Abstract: Inverter-based resources (IBRs) exhibit different short-circuit characteristics compared to traditional synchronous generators (SGs). Hence, increased uptake of IBRs in the power system is expected to impact the performance of traditional protective relay schemes—set under the assumption of a SG-dominated power system. Protection engineers need to study these challenges and develop remedial solutions ensuring the effectiveness of system protection under higher levels of IBRs. To address this need, this paper studies the impact of IBRs on a variety of protective relay schemes including line distance protection, memory-polarized zero sequence directional protective relay element, negative sequence quantities-based protection, line current differential protection, phase comparison protection, rate-of-change-of-frequency, and power swing detection. For each protection function, potential misoperation scenarios are identified, and recommendations are provided to address the misoperation issue. The objective is to provide an improved understanding of the way IBRs may negatively impact the performance of traditional protection schemes as a first step towards developing future remedial solutions ensuring effective protection under high share of IBRs.

Design of DC system protection

Abstract: A modified Z-source breaker topology is introduced to minimize the reflected fault current drawn from a source while retaining a common return ground path. A conventional Z-source breaker does not provide steady-state overload protection and can only guard against extremely large transient faults. The Z-source breaker can be designed for considerations affecting both rate of fault current rise and absolute fault current level, analogous in some respects to a “thermal-magnetic” breaker. The proposed manual tripping mechanism enables protection against both instantaneous current surges and longer-term over-current conditions. The fault operation intervals of the proposed Z-source breaker topologies are demonstrated in SPICE simulation.

Multi-Agent based Control and Protection of Power Distributed System - Protection Scheme with Simplified Information Utilization -

Abstract: On the premise of future improvement of information infrastructures, we proposed a multi-agent based protection scheme for distribution systems with high penetration of distributed generators (DGs) In the proposed protection scheme, various relays designed as relay agents cooperate to locate and isolate fault zone Binary state signal, eg current direction, magnitude, etc is determined autonomously just by sensing a sudden change of the current at the relay Each relay simultaneously utilizes binary state signals provided by the other relays at breakers involved to the same zone for detecting a fault location By using PSCAD/EMTDC, the proposed protection scheme is tested with a distribution system which has loop structure and is divided into several protection zones Extensive simulation studies show that the proposed protection scheme can be adopted for various conditions of distribution structure and DGs operation, and may contribute to a selective and quick disconnection of faulted zone with less coordination between relays