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.

A new protection scheme for DC microgrid using line current derivative

Abstract: Protection scheme for AC transmission systems are well understood and matured On the other hand, DC system is still facing a challenge in developing proper protection scheme because of its natural characteristics A protection scheme, which utilizes some of the developed techniques for AC system, and modified to suit the DC system characteristics, is proposed in this paper The scheme is based on the concept of DC current profile under transients, which depends on the fault location This property is combined with the directional feature to achieve the protection of a DC microgrid The proposed scheme is demonstrated on the ring type DC microgrid system, which is able to detect the fault in the DC system, and also ensure its backup protection The proposed concept is verified and tested through MATLAB/Simulink simulations

The Laboratory Investigation of a Digital System for the Protection of Transmission Lines

Abstract: The results and conclusions of a feasibility study of a digital system for the protection of transmission lines are presented. In this laboratory investigation, a computer with its data acquisition system was connected to a transmission line model. The minicomputer program for a two-zone stepped-distance protection scheme utilizes an algorithm based on the system differential equation. Extensive testing with a wide range of fault types, fault locations, fault inception angles, and power flows demonstrated the success of the system. Trip times were on the average equal to or less than 0.5 cycle for the primary protection zone. The program successfully determined fault type and location with the fault locations usually within a mile over the range of the model of a 72 mile transmission line.

Future Shipboard MVdc System Protection Requirements and Solid-State Protective Device Topological Tradeoffs

Abstract: The search for the optimum architecture for shipboard medium voltage dc integrated power systems must take into account the short-circuit protection in addition to overarching goals of efficiency, survivability, reliability of power, and cost effectiveness. Presently, accepted approaches to protection are “unit-based,” which means the power converter(s) feeding the bus coordinate with no-load electromechanical switches to isolate faulted portions of the bus. However, “breaker-based” approaches, which rely upon solid-state circuit breakers for fault mitigation, can result in higher reliability of power and potentially higher survivability. The inherent speed of operation of solid-state protective devices will also play a role in fault isolation, hence reducing stress level on all system components. A comparison study is performed of protective device topologies that are suitable for shipboard distribution systems rated between 4 and 30 kVdc from the perspectives of size and number of passive components required to manage the commutation energy during sudden fault events and packaging scalability to higher current and voltage systems. The implementation assumes a multichip silicon carbide (SiC) 10-kV, 240-A MOSFET/junction barrier Schottkey (JBS) diode module.

Development and implementation of a power system fault diagnosis expert system

Abstract: This paper describes a fault diagnosis expert system installed at the Tohoku Electric Power Company. The main features of this system are careful selection of the inferencing input data, rapid inferencing, integration of the expert system with other systems in a practical structure, and the adoption of a domain shell. This system aims for improved practicability by using time-tagged data from circuit breakers, protective relays, and automatic reclosing relays in addition to the input data used in earlier systems. Furthermore, this system also uses data from fault detection systems that locate fault points within electric stations. This system uses an AI-specific back-end processor to perform inferencing rapidly. Additionally, this fault diagnosis expert system is interfaced and integrated with a restorative operations expert system, an intelligent alarm processing system, and a protective relay setting and management system. The authors developed and adopted a power system fault diagnosis domain shell to ease system development, and used the protective relay operation simulation function of a protective relay setting and management system for system verification. >

Model reduction for analysis of cascading failures in power systems

Abstract: In this paper, we apply a principal-orthogonal decomposition based method to the model reduction of a hybrid, nonlinear model of a power network. The results demonstrate that the sequence of fault events can be evaluated and predicted without necessarily simulating the whole system.