Conference Paper

Optimum Fault Current Limiter Placement

I-Shou Univ., Kaohsiung
DOI: 10.1109/ISAP.2007.4441611 Conference: Intelligent Systems Applications to Power Systems, 2007. ISAP 2007. International Conference on
Source: IEEE Xplore

ABSTRACT

Due to the difficulty in power network reinforcement and the interconnection of more distributed generations, fault current level has become a serious problem in transmission and distribution system operations. The utilization of fault current limiters (FCLs) in power system provides an effective way to suppress fault currents and result in considerable saving in the investment of high capacity circuit breakers. In a loop power system, the advantages would depend on the numbers and locations of FCL installations. This paper presents a method to determine optimum numbers and locations for FCL placement in terms of installing smallest FCL parameters to restrain short-circuit currents under circuit breakers' interrupting ratings. In the proposed approach, sensitivity factors of bus fault current reduction due to changes in the branch parameters are derived and used to choose candidates for FCL installations. A genetic-algorithm-based method is then designed to include the sensitivity information in searching for best locations and parameters of FCL to meet the requirements. Test results demonstrate the efficiency and accuracy of the proposed method.

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    • "The choice of where in a system to place current limiting devices to best maintain synchronization among generators has become a significant issue, for which we propose a solution. References [1] and [2] describe how genetic algorithms can be used to find the optimal placements of the minimum number of FCLs to meet maximum fault current objectives. After specifying a maximum desired fault current, combinations of FCLs at different locations are compared to find the optimal placements. "
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    ABSTRACT: Judicious placement of inductive fault current limiters (IFCLs) in isolated power systems can increase the robustness of generator synchronization during and after short-circuit faults, while also improving continuity of power to the system loads. Our work defines optimal placements of IFCLs so as to protect the synchronization of multiple generators, and it defines the proper trip settings for the IFCLs so that they coordinate well with each other, and with the system's circuit breakers. Our work considers both radial and ring bus structures, but not mesh structures. The IFCL placement technique is demonstrated in a power network containing four buses in a ring arrangement. The system receives power from two main turbo-generators (36 MW each) and two auxiliary turbo-generators (4 MW each). In this system, the optimal locations for the IFCLs were found to be near the bus ties of the two larger generators. Further, the placement strategy for locating IFCLs in a power system with ring structure is developed. For this arrangement, fault currents were limited for all fault conditions while assuring maximum availability of power to the loads. Coordination between the IFCLs and the system circuit breakers is analyzed for IFCLs in these locations, and verified by simulation results.
    Preview · Conference Paper · Jun 2010
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    • "Generally speaking, FCLs can be installed at the generator feeder, at inter-connected busses, and at load feeders. References [5] and [6] describe how genetic algorithms can be used to find the optimal placements of the minimum number of FCLs to meet objectives of limiting the maximum fault current. After specifying a maximum desired fault current, combinations of FCLs with different locations are compared to find the optimal placements. "
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    ABSTRACT: With the increasing capacity of power system, fault currents (CBs) may exceed the interrupting capacity ratings of circuit breakers. Fault current limiters (FCLs) can be applied to maintain circuit breakers within their interrupt ratings. The degree of fault current limiting on system performance is analyzed in radial and meshed system structures. Heavy limitation modes and light limitation modes are defined. The choice of limitation mode should be based on the locations of FCLs. We discovered that FCLs should work in light limitation mode to maintain the function of circuit breakers in a radial structure, or a matrix structure with changeable relay schemes, but that FCLs should work in heavy limitation mode in a matrix structure with unchangeable relay schemes, to limit the fault current contribution from newly-added distributed generators. The analyses are verified by simulation results.
    Preview · Conference Paper · Apr 2010
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    ABSTRACT: The growth of demand invariably lead to higher and higher fault currents, and as a consequence protection devices must have higher ratings. The integration of distributed energy resources further complicates protection schemes, especially those that assume a radial distribution scheme and power flowing in only one direction. These conditions generate an increasing demand for fault current limiters to keep fault currents within the ratings of existing protection equipment as well as to minimize the impact of distributed generation on the grid during faults. However, placement of protection equipment must be carefully considered in order to keep them cost effective and to prevent the limiters themselves from disrupting existing protective measures. This paper explores several placement and coordination guidelines, as well as provides simulations of fault current limiters placed in substations with ring bus and double bus configurations, respectively.
    No preview · Conference Paper · Dec 2008
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