Restoration of Directional Overcurrent Relay Coordination in Distributed Generation Systems Utilizing Fault Current Limiter
ABSTRACT A new approach is proposed to solve the directional overcurrent relay coordination problem, which arises from installing distributed generation (DG) in looped power delivery systems (PDS). This approach involves the implementation of a fault current limiter (FCL) to locally limit the DG fault current, and thus restore the original relay coordination. The proposed restoration approach is carried out without altering the original relay settings or disconnecting DGs from PDSs during fault. Therefore, it is applicable to both the current practice of disconnecting DGs from PDSs, and the emergent trend of keeping DGs in PDSs during fault. The process of selecting FCL impedance type (inductive or resistive) and its minimum value is illustrated. Three scenarios are discussed: no DG, the implementation of DG with FCL and without FCL. Various simulations are carried out for both single- and multi-DG existence, and different DG and fault locations. The obtained results are reported and discussed.
- SourceAvailable from: Ebrahim Farjah
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- "Therefore, in this research, a novel method based on KF is proposed for fault location. Fault current limiters (FCLs) are another suitable alternative of the relays utilized in , which can quickly limit fault current after fault occurrence , . Furthermore, protection relays result in perfect segregation of faulty sections from the network , while FCL can preserve the integrity of the network's sections . "
ABSTRACT: Abstract— Penetration of Distributed generations (DG) are becoming more and more widespread in the current electric power networks. One of the most important issues regarding utilization of DG in power systems is related to their impact on fault current level. In this regard, a multi-agent-based fault current limiting scheme for microgrids is presented in this paper. A typical microgrid is divided into several sections. A number of Superconducting Fault Current Limiters (SFCLs) which are located in suitable locations of the network, can suppress transient fault currents. Fault location is identified using several Fault Location Identification Units (FLIUs), which are installed in suitable places. In each FLIU, fault current is estimated using a Kalman filter and then residual signal is generated from the calculated and measured fault current. In fault condition, faulty section is identified by analyzing the information of FLIUs in the network. Then, the impact of the faulty section on the sound sections is minimized by utilizing the proposed fault current limiting scheme. Capabilities of the proposed method are evaluated using different simulations on a benchmark microgrid.IEEE Transactions on Power Delivery 01/2013; 29(2). DOI:10.1109/TPWRD.2013.2282917 · 1.66 Impact Factor
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- "The islanding operation with DGs is prohibited due to the restoration , personnel safety and power quality issues . Therefore , the DGs need to be disconnected even for temporary faults . As the penetration level increases, the disconnection of these DGs drastically reduces the benefits of DGs . "
ABSTRACT: The disconnection of distributed generators (DGs) from a distribution network for every abnormal condition drastically reduces the DG benefits and system reliability when DG penetration level is high. The DGs can be used to supply the load demand in the absence of grid supply if DGs are allowed to operate in islanded mode. In this paper, protection issues associated with disconnection of DGs are addressed in the context of a radial distribution feeder. Protection strategies are proposed to allow islanded operation and to restore the system performing auto-reclosing maintaining as many DG connections as possible. An overcurrent relay based protection scheme is proposed for a converter based DG connected radial feeder to operate either in grid-connected or islanded mode maximizing the DG benefits to customers. Moreover, an effective method is proposed to restore the system with DGs using auto-reclosers. The proposals are verified through PSCAD simulation and MATLAB calculations.01/2011; DOI:10.1109/IECON.2011.6119434
- "It also uses PI controller while in  Genetic Algorithm is used to find the best solution for controller parameters. Reference  also proposed a similar control method using fuzzy logic controllers. As expressed in , there exist four degrees of freedom to control UPFC which are amplitudes and phase angles of both series and shunt branches of UPFC. "
Conference Paper: A novel method for Hysteresis based control of UPFC[Show abstract] [Hide abstract]
ABSTRACT: Appropriate design and use of Unified Power Flow Controller (UPFC), which has the ability of controlling the bus voltage level and transmission line power flow simultaneously, provides suitable conditions to improve restructured power systems operation. In this paper, a novel control method is proposed for Hysteresis based UPFC, which uses four degrees of freedom to control bus voltage, DC link voltage, and active and reactive transmission line power flows independently. Results obtained by simulations with PSCAD/EMTDC show that proposed control method is more effective than the reported methods in achieving better power quality indices and more stability i.e. less overshoots and settling times.Power Engineering and Optimization Conference (PEOCO), 2010 4th International; 07/2010