Travelling-wave starting element is an integral part of the ultra high-speed protection. Existing design method depends on engineering experience, low accuracy in travelling-wave signal recognition, easy to trip frequ...
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Travelling-wave starting element is an integral part of the ultra high-speed protection. Existing design method depends on engineering experience, low accuracy in travelling-wave signal recognition, easy to trip frequently or refuse to trip. To solve these problems, through mass of starting signal simulation and analysis under different fault conditions, this paper focuses on the travelling-wave starting element and figures out the travelling-wave identification method. This paper summarizes the frequency and voltage characteristics of travelling-wave head, puts forward a new method in real-time travelling-wave fault identification. In addition, the analysis course included in this paper is a useful attempt that can be used in similar fault travelling-wave analysis.
The implementation of non-communication protection of double circuit line systems based on two independent relays has disadvantages like information shareless,complex connection and lack of economic. This paper resear...
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Smart substation is the base of smart grid and it is made up of a lot of IEDs (intelligent electric device). Synchronized phasor measurement unit (PMU) plays a very important role in the smart grid, and a great deal o...
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Standardization is the development tendency of information exchange among control centers. Based on the standard in IEC 61970, an information exchange model suitable for coordinated automatic voltage control (CAVC) am...
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Standardization is the development tendency of information exchange among control centers. Based on the standard in IEC 61970, an information exchange model suitable for coordinated automatic voltage control (CAVC) among multi control centers is proposed. Firstly, the contents of information flow of CAVC is analyzed and the definition of coordinated control model for information exchange is given;then the common information model is extended and a standardized information model for CAVC is designed;and then based on component interface specification, a standardized information exchange interface for CAVC is designed and its architecture for information exchange as well as its information exchange procedure are given. The presented information exchange model possesses wide application prospect in the implementation of information exchange among multi CAVC control centers for future smart grids.
A substation three-phase nonlinear state estimation method based on zero impedance branches is presented in order to eliminate topology and analogy errors at substation level and accordingly enhance the control center...
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In the annular power distribution system, short-circuit fault of bus-bars will do fatal harm to aircraft, and it is necessary to protect the ring-net bus-bars. Protecting bus-bars has to meet the requirements that pro...
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Lightning is a major cause of power interruptions in power transmission lines. Nowadays the Leader Progression Model is an advanced method to evaluate the shielding failure probability of transmission lines. Calculati...
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power grid and communication network, which depends on each other to provide proper functionality, are becoming more and more coupled together. Failure of a fraction of nodes in communication networks may lead to a fa...
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power grid and communication network, which depends on each other to provide proper functionality, are becoming more and more coupled together. Failure of a fraction of nodes in communication networks may lead to a failure even a cascade of failures in power grid. Wide area protection is highly dependent on communication. The failure of communication in some part of wide area protection system will affect the realization of the function to prevent cascading outages and result in serious consequences. Based on Manchester, OPA and hidden failure cascading failure models and considered the feature of relay protection, an improved cascading failure model is established. Then it is used to analyze the dynamic process of communication fails in wide area protection system and IEEE 30 bus system is employed to demonstrate the efficiency of the proposed method. Results show that communication failure in protection system will accelerate the cascading outages of power grid. Effective solutions to reduce the communication risk are discussed. The work of this paper is availab.e for reference to analyze the process of cascading outages and design protection system preventing cascading outages.
Aimed at power system large-scale blackouts, the paper firstly analyzes the existing problems of current protective relaying and emergency control in power grid. A novel system protection based on local information, p...
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Aimed at power system large-scale blackouts, the paper firstly analyzes the existing problems of current protective relaying and emergency control in power grid. A novel system protection based on local information, protecting both the equipment and power system secure is then proposed, which scheme consists of: identification of fault flow transferring identification, adaptive overload protection and active load shedding strategy. The processes and system structure are introduced, and the following research points are also discussed in this paper.
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