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This paper presents an accurate track modeling for fault current on dc railways based on MATLAB/Simulink. With the introduction of skin effect of short-circuit current, the simulation of short-circuit fault based on MATLAB/Simulink is proposed. By comparing and investigating the waveforms of remote short-circuit current with and without skin effect, the paper pointed out the difference between these...
This paper presents a simulation of articulated neutral section insulator in DC Railway System. With the introduction of Beijing subway structure, the special way of the connection of neutral section is proposed. By comparing and investigating the waveforms of locomotive passing neutral section current and starting current, the paper pointed out the difficulty of discrimination between remote short...
This paper presents two comprehensive models of DC subway traction system to simulate the starting-up process using Matlab/simulink. One is DC motor driven, the other is AC motor driven. The model includes substation rectifiers, the track and the different driven subway trains. The objective of the model is to study the short circuit faults and the train starting current. Analysis and conclusion of...
This paper presents a new relay for the protection of power transmission systems by using the global positioning system (GPS) and the transient polarity comparison techniques, the positional polarity comparison relay. A specially designed protection relay detects the fault generated high frequency current transient signals and records the polarity of the transient signal and the time instant corresponding...
Voltage stability is one of the aspects of the power system stability. Since regulating transformers are more and more used in modern power system, tap change has often been considered as a principal mechanism that may lead to voltage collapse, but tap change can also rescue a would-be collapse system by extending the power transfer limit. Using time domain medium-and-long term voltage stability simulation...
This paper presents a new protection scheme for high-speed protection of transmission lines, the Integrated Positional Protection scheme. The concept of integrated protection is firstly introduced, in which a centralized protection relay provides the protection for multiple transmission lines. The proposed scheme is based on a specially integrated relay unit, which is installed at each substation...
The fast development in both microprocessor and transducer technologies has enabled fault detection techniques to be considered which were impractical in the past and encouraged interest in the utilization of fault generated transients for protection. This paper presents an integrated approach for high-speed protection of transmission lines. The technique uses a fault transient detector unit at the...
This paper presents a simulation model of DC traction system which is based on bilateral power supply mode. The model of two substation rectifiers in one track section has been proposed which is according to practical situation. The modeling was conducted with respect to the variations of the starting-up process and short circuit conditions. By comparing and investigating the simulation results of...
This paper presents a new DC feeder protection based on wavelet transform. The model of two substation rectifiers in one track section has been proposed which is according to practical situation. The remote short-circuit current is determined mainly by the steel rail impedance, which is time varying due to the skin effect. In contrast, impedances of the traction motor and the contact wires, and the...
This paper presents a new scheme for power line autoreclosure technology, the integrated adaptive optimal reclosure. The background of the development is firstly outlined and the basic principles of these new techniques are described. These include the adaptive reclosure and the optimal reclosure techniques. The new scheme proposed is based on the latest development in digital substation, in which...
This paper presents a novel relay for power transmission line systems, which is based on a combination of positional and boundary protection principle. The relay installed at a substation is responsible for the protection of the transmission lines associated with the substation. The relay is able to offer fast trip for any fault on its protected line sections without the need for communication link...
This paper presents an integrated PMU and protection scheme for power systems. The scheme integrates local and wide area control and protection systems by implementing the WAMS function and substation protections into one system to identify the overload caused by flow transfer from isolation of main trunk line. This integrated system mainly consists of three major components: local interface unit...
The paper studies distribution network with comprehensive micro-grid systems with an aim to design an advanced protection and control scheme. The proposed integrated protection and control (IPC) unit, interfacing to the substation measurement devices and micro-grid components through a substation optical Ethernet, is responsible for the protection of the distribution substation and control of its...
This paper presents a new integrated protection relay and its associated scheme for distributed generation systems. In the scheme, an integrated relay is responsible for the protection of both line sections associated with the substation bus. Based on conventional directional overcurrent protection technique, the basic principle of the new relay is to determine whether a fault is on the protected...
This paper presents the design of new real time digital simulator (RTDS) based novel relay test systems. The background of the developments in protection relays and their associated technologies, such as optical transducers and IEC 61850, are introduced. The new developments in RTDS systems are described. It is shown that the recent developments in transducers and communication technology will have...
This paper presents a new integrated protection scheme for transmission lines. The concept of the integrated protection is firstly introduced, in which a centralized protection system provides the protection of multiple power plant or a substation. A total integrated protection scheme based on current differential protection techniques is further described. In the proposed scheme, the specially designed...
This paper presents a novel integrated protection scheme for distribution lines based on Transient Polarity Comparison technique. In the proposed scheme, the specially designed interface units are installed at each substation and connected to the CTs on every line associated to the busbar. The unit converts the measured signals to optical format and sends to the central protection relay through a...
This paper presents a new technique for the protection of power transmission systems by using the global positioning system (GPS) and fault generated transients, the integrated positional protection technique. The technique is based on the detection and processing of fault generated high frequency transient signals, in which a centralized protection relay provides the protection of multiple transmission...
This paper first outlines an advanced integrated protection scheme based on the latest developments in protection and communication technologies. The paper then gives a description of the communication networks and systems in substations based on the IEC61850 standard. The paper emphasizes the construction of the information model and the analysis of communication capacity of IEC61850 for the integrated...
This paper presents an integrated accelerated protection scheme for distribution systems based on the conventional directional overcurrent (OC) protection. An integrated relay in a distribution substation, connected to both the incoming and outgoing lines associated with the station busbar, is responsible for the protection both line sections. The increase in the operating speed is achieved by identifying...
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