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Due to the large amount of branches and high grounding resistance of the distribution network, the earth fault location has not been solved effectively. A live location method is proposed for the single-phase-to-earth fault section in the neutral point resonant grounded system. By this method, the compensation current of arc-suppression coil is adjusted after the metallic earth fault occurs. And the...
The value setting of the traditional distance protection has become very difficult for the distribution system with distributed generators (DGs) owing to the randomness of the DG output power. This paper proposes a new adaptive distance protection scheme to solve this problem. Firstly, on the basis of the connected point of DGs, the protected feeders are divided into different zones, with adaptive...
To realize the aim that in 2020 the carbon dioxide emissions per unit of GDP in China dropped to 40% ~ 45% of that in 2005, it's compulsory to take full advantage of the clean and renewable energy, develop distributed generation technology and realize low-carbon generation scheduling. According to the characteristics of photovoltaic and wind turbine, considering different generation cost and greenhouse...
Vacuum switch as a great potential for development of new power switch, in the low voltage level has a strong advantage, but to the development of high-voltage level encountered a relatively large resistance. This paper provides a kind of phase selection function, photoelectric control, with multi-take energy operate the power system, with permanent magnetic actuator of the modular smart vacuum switch...
The bi-directional DC/DC converter with high power rate plays a key role in power storage system, while it converts DC voltage or DC current for the power storage battery, and then come to the need of DC voltage/current in applications. It illustrates the design of the system hardware and software realization based on this local controller and the host computer structure in detail, in which the local...
Wind power forecasting has great significance to the connection of wind farms to the electric power system. This paper analyzes individual forecast models, such as the time series forecasting, Elman network forecasting that based on the chaos theory, grey neural network forecasting, and generalized regression neural network forecasting, etc., then puts forward an entropy weight combination prediction...
As an effective method of saving energy and avoiding market risks, generation rights trade has been carried out in some provinces and regional power companies. This paper analyzes the existing generation rights trade models and their algorithms, points that the results calculated by high-low match mode are not the optimal, because the trade order is inherent characteristic owned by this mode, which...
With the widely installation of Phasor Measurement Units (PMUs) in power system and the increasing requirement of the real-time monitoring and control, a novel power system topology analysis algorithm is proposed with high precise information from PMUs to improve the performance of current network topology analysis. First of all, a method of identifying switch status is established to correct the...
Limiting the short-circuit current is of great significance to keep the safe and steady running of the power system. A novel fault current limiter (FCL) is presented. A high speed switch is used to rapidly break the short-circuit current. A triggered vacuum switch (TVS) is used to discharge a precharged pulse capacitor so as to quench the arc in the high speed switch quickly and to realize the active...
The integration of photovoltaic generation into the power grid is one of the most significant measures for the guarantee of national energy security, the construction of low-carbon society and the enforcement of National Twelfth Five Years Plan in China. Based on the in-depth surveys, this paper presents the framework of the infrastructure construction planning of photovoltaic generation from the...
Advanced distribution operation is an increasingly important function for smart grid, and a reliable communication network constitutes the core of the advanced distribution automation system. Ethernet Passive Optical Network (EPON) is regarded as a promising fiber-based communication technique for advanced distribution automation because it is not only high-speed, cost-effective but also scalable...
Especially influenced by the rising number of renewable and distributed power generation plants and so-called unbundling, the controllability and protection of power supply systems are becoming ever more complex as these systems are developed further. To securely meet these challenges a reliable observability of the power system is needed. Novel digital measurement equipment such as phasor measurement...
With the rapid development and interconnection of power systems, the low frequency oscillations(LFO) has become one of the serious factors threatening the power system stability. Thus, how to quickly locate the source of LFO and implement controller to suspend it, is an urgent task. The general approach to locate the sources of LFO is using the node contribution factor(NCF), which indicating the contribution...
Once the power system low frequency oscillation occurs, the operators desire to find out the dominant mode LFO so as to take measures to suspend it. This paper proposes an identification method for dominant mode of LFO based on Prony algorithm in wide-area measurement system (WAMS). The presented method contains three steps, the first step is preprocessing of Prony analysis result, the second step...
This paper proposes a new control design scheme for doubly fed induction generator (DFIG) based wind generation systems to damp interarea oscillations of power systems. The control system of DFIG consists of two parts. The first part is the primary power and voltage (PV) control. The second part is a supplementary damping controller (SDC) based on PV control, designed to enhance damping of interarea...
The control systems in current and future power systems need reliable real-time information transmission. Internet Protocol (IP) based communication systems for wide-area frequency stability predictive control systems are proposed in this paper. The key technologies, such as network topology, communication protocols, and communication modes are studied. The frequency stability predictive control algorithm...
Smart grids rely on a dependable information infrastructure for the monitoring and control applications. Two elements can enhance the suitability of the communication and control infrastructure for such smart grid applications. Overlay networks allow to resiliently deal with nodes that appear and disappear, as well as with the dynamic nature of the power values these nodes represent in a smart grid...
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