The increase in the number of sensitive loads in power systems has made power quality,particularly voltage sag,a prominent problem due to its effects on consumers from both the utility and customer perspectives.Thus,t...The increase in the number of sensitive loads in power systems has made power quality,particularly voltage sag,a prominent problem due to its effects on consumers from both the utility and customer perspectives.Thus,to evaluate the effects of voltage sag caused by short circuits,it is necessary to determine the areas of vulnerability(AOVs).In this paper,a new method is proposed for the AOV determination that is applicable to large-scale networks.The false position method(FPM)is proposed for the precise calculation of the critical points of the system lines.Furthermore,a new method is proposed for the voltage sag monitor(VSM)placement to detect the fault locations.A systematic placement scheme is used to provide the highest fault location detection(FLD)index at buses and lines for various short-circuit fault types.To assess the efficiency of the proposed methods for AOV determination and VSM placement,simulations are conducted in IEEE standard systems.The results demonstrate the accuracy of the proposed method for AOV determination.In addition,through VSM placement,the fault locations at buses and lines are detected.展开更多
High voltage direct current (HVDC) transmission is an economical option for transmitting a large amount of power over long distances. Initially, HVDC was developed using thyristor-based current source converters (CSC)...High voltage direct current (HVDC) transmission is an economical option for transmitting a large amount of power over long distances. Initially, HVDC was developed using thyristor-based current source converters (CSC). With the development of semiconductor devices, a voltage source converter (VSC)-based HVDC system was introduced, and has been widely applied to integrate large-scale renewables and network interconnection. However, the VSC-based HVDC system is vulnerable to DC faults and its protection becomes ever more important with the fast growth in number of installations. In this paper, detailed characteristics of DC faults in the VSC-HVDC system are presented. The DC fault current has a large peak and steady values within a few milliseconds and thus high-speed fault detection and isolation methods are required in an HVDC grid. Therefore, development of the protection scheme for a multi-terminal VSC-based HVDC system is challenging. Various methods have been developed and this paper presents a comprehensive review of the different techniques for DC fault detection, location and isolation in both CSC and VSC-based HVDC transmission systems in two-terminal and multi-terminal network configurations.展开更多
文摘The increase in the number of sensitive loads in power systems has made power quality,particularly voltage sag,a prominent problem due to its effects on consumers from both the utility and customer perspectives.Thus,to evaluate the effects of voltage sag caused by short circuits,it is necessary to determine the areas of vulnerability(AOVs).In this paper,a new method is proposed for the AOV determination that is applicable to large-scale networks.The false position method(FPM)is proposed for the precise calculation of the critical points of the system lines.Furthermore,a new method is proposed for the voltage sag monitor(VSM)placement to detect the fault locations.A systematic placement scheme is used to provide the highest fault location detection(FLD)index at buses and lines for various short-circuit fault types.To assess the efficiency of the proposed methods for AOV determination and VSM placement,simulations are conducted in IEEE standard systems.The results demonstrate the accuracy of the proposed method for AOV determination.In addition,through VSM placement,the fault locations at buses and lines are detected.
文摘High voltage direct current (HVDC) transmission is an economical option for transmitting a large amount of power over long distances. Initially, HVDC was developed using thyristor-based current source converters (CSC). With the development of semiconductor devices, a voltage source converter (VSC)-based HVDC system was introduced, and has been widely applied to integrate large-scale renewables and network interconnection. However, the VSC-based HVDC system is vulnerable to DC faults and its protection becomes ever more important with the fast growth in number of installations. In this paper, detailed characteristics of DC faults in the VSC-HVDC system are presented. The DC fault current has a large peak and steady values within a few milliseconds and thus high-speed fault detection and isolation methods are required in an HVDC grid. Therefore, development of the protection scheme for a multi-terminal VSC-based HVDC system is challenging. Various methods have been developed and this paper presents a comprehensive review of the different techniques for DC fault detection, location and isolation in both CSC and VSC-based HVDC transmission systems in two-terminal and multi-terminal network configurations.
