The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper presents a novel integrated protection scheme for distribution networks using the transient polarity directional comparison technique. The technique is based on the detection and processing of fault generated transient current signals, in which specially designed protection relays are installed at each substation of a distribution network. The transient detection unit of the relay detects...
This paper presents an integrated boundary protection scheme for power transmission line systems. The scheme combines the latest developments in two areas of power system protection, the transient based protection and the integrated protection. In the proposed scheme, an integrated relay based on boundary protection principle installed at a substation is responsible for the protection of all transmission...
This paper describes the optimum power supply solution for 2008 olympic international broadcast centre (IBC). IBC is the most important building of 2008 Beijing Olympic Games, it will undertake all broadcasting tasks during the game. Therefore high power supply reliability is required. Even a short period outage is not allowed. The switch operation between power sources should be seamless. Diesel...
This paper describes a new current differential relay. A current differential plane is presented firstly to depict different system statuses. Two traditional current differential protection schemes are discussed by plotting their operating and restraint region in the current-differential plane. A relay characteristic with more appropriate operating and restraint region is plotted in the plane by analyzing...
This paper presents a new directional comparison protection scheme specially designed for distribution systems. A number of well-proved directional techniques were chosen for this study. To evaluate their performances, a typical distribution line system was modeled using EMTP, which is able to offer many variations to cover all possible fault conditions such as with different fault types, fault locations,...
This paper presents the design of new real time digital simulator (RTDS) based 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 great...
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 combined integrated protection relay for the protection of double circuit lines is then introduced, which combines the longitudinal current differential...
This paper reports on the development of integrated protection for power system. The background of the development is firstly introduced, in which a centralized protection system (or relay) provides the protection of multiple power plant or a substation. A novel integrated protection scheme for distribution system is described. The scheme is based on overcurrent protection technique, in which specially...
A novel criterion for neutral current differential protection is presented in this paper, which is based on a full research into traditional neutral current differential protection schemes used in transmission lines. Compared to traditional criteria, the novel one is able to increase sensitivity for an internal fault and remain stable for an external fault. Simulation studies show that the sensitivity...
This paper presents studies on an Ethernet based substation communication system for supporting the integrated protection. Recent developments in power system protection are firstly outlined, the paper then describes a substation integrated protection system supported by an advanced communication network. Detailed discussion and design on the communication network and the transmission protocol, the...
This paper proposes an advanced substation communication system for supporting the latest development in power system protection - integrated protection. Recent developments in power system protection are firstly outlined, and then a description of a substation integrated protection system supported by an advanced communication network is given. Based on the proposal, there are 3 major components...
This paper presents a new integrated protection scheme based on distance protection technique. An integrated protection relay is installed at a substation and interfaced to every line through the CTs and busbar VT. The relay is also interfaced to the substation communication network which is communicated with all neighboring substations. The directional detection, phase selection and adaptive distance...
A novel criterion for neutral current differential protection is presented in this paper, which is based on a full research into exist neutral current differential protection schemes used in transmission lines. Compared to traditional ones, the novel criterion can improve the sensitivity under internal fault conditions and improve reliability under external fault conditions. More importantly, the...
This paper presents a new directional comparison protection scheme specially designed for distribution systems. A comprehensive study is performed on different directional discrimination algorithms and relaying schemes in order to assess their performances in distribution systems. An integrated solution was proposed, which combines better performed directional algorithms, such as the Negative sequence-based...
This paper proposes a new current mode derived by a new modal transformation technique, the alpha mode. The mode is used to detect and distinguish between internal and external faults for power line protection, based on a new transient directional comparison technique using current alone. The technique uses the symmetrical component to replace Clark or Karrenbauer transformation to decouple the three...
Based on the analysis of operation criteria of line current differential relays, this paper proposed a new criterion. Comparing with the existing ones, the proposed criterion has a higher sensitivity for internal faults and more dependability for external faults. Combined with fault components, the new operation criterion offers better performance. Theory calculation and RTDS simulation conducted...
This paper reports on the development of integrated protection for power system. The concept of integrated protection is introduced, in which a centralized protection system (or relay) provides the protection of multiple power plant or a substation. Examples are given of the protection schemes with the features of integrated protection which are currently under development. A novel integrated protection...
The cross differential protection used to protect parallel double transmission lines is able to offer fast operation without the need for communication link. However, the conventional cross differential relay is not sensitive enough to protect EHV transmission lines because of the requirement for high setting values. In this paper, a percentage cross differential element is used to improve the performance...
This paper presents a new practical accelerated overcurrent protection scheme for single circuit breaker radial distribution feeder and the implementation of this new scheme into latest numerical relay. Extensive tests have been conducted using the real time digital simulator (RTDS) with respect to a typical single circuit breaker multi-section system. The results prove that the new protection relay...
The paper describes the design and operation of a transient polarity comparison technique for the protection of transformer-feeder circuits. In contrast to conventional directional comparison technique, the proposed technique utilises fault generated transient signals rather than 50 Hz components. By this arrangement, the performance of the relay is not affected by problems using power frequency measurement,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.