Applied Mechanics and Materials Vols. 448-453

Abstract: In generator setting calculation, the loss-of-excitation protection impedance round is in the R-X plane, while the low excitation limit setting is in the P-Q plane. In this paper, the R-X plane and the P-Q plane coordinate conversion on the matching of generator low excitation limit setting and loss-of-excitation protection are proposed. Using a power plant example, the method has been proved convenient.

Abstract: According to the problem of optimal power flow (OPF), the optimization objectives including minimization of total fuel cost for generating units, minimization of emission for atmospheric pollutants, minimization of active power losses and minimization of voltages deviations are established. The paper uses fuzzy membership functions instead of multi-objective functions to form fuzzy optimal power flow in the optimal power flow calculation process. The novel artificial bee colony (ABC) algorithm is proposed to solve OPF problem with multi-objective. The proposed approach is applied to the OPF problem on IEEE30 test systems. And the simulation results verify the effectiveness of the proposed method.

Abstract: Ferro-resonance due to the voltage transformer (PT) occurs is a normal fault of power systems. With the nonlinear excitation characteristics of PT, its saturation is considered to cause the Ferro-resonance. Based on the ATP-EMTP platform, and considering the nonlinear excitation characteristics of PT, this paper builds a ferro-resonance simulation model of PT, and simulates high frequency resonance, fundamental resonance, and fraction frequency resonance separately. The factors affecting resonance are also discussed, to provide theoretical basis for the suppression of ferro-resonance in power system.

Abstract: Recently, voice dispatching telephone is applied as one of information interactive by power grid dispatching in China, playing a significant role in the progress of power grid dispatching. However, with the increasing of grid scale, more and more information should be figured out by dispatchers. Conventional dispatching telephone in communication presents enormous challenge, thus, much effort should be made to solve this problem. In the article, the shortcomings of dispatching telephone in communication are systematically analyzed by the point of our actual country power grid dispatching. To remedy telephones shortcomings, text technology is introduced and a uniform dispatcher interactive platform is formed. This platform meets the requirements of interactive in power grid dispatching perfectly.

Abstract: An important part of the Xinyang power grid voltage stability online intelligent warning system was to research into the current system of EMS real-time power grid operation parameters and power networks offline data splicing integration, forming a set of online PSASP (Power System Analysis Software Package) trend data, implementing preventive voltage stability calculation. By splicing model of Xinyang grid online data integration and practice, summed up the grid online data splicing method and the model, this article mainly introduced the offline and online data mapping change reason, function is established. It had been verified by actual data achieved by the method can significantly improve the accuracy of the data. It was a kind of practical data online and offline networks data integration method.

Abstract: As an effective means to reduce or eliminate power accidents, dispatch operation ticket system has gained more and more concerns and application. The existing dispatch operation ticket system is most based on logic rules, and strongly relying on network topology, which is hard to be extended. In view of the above mentioned problem, a new power grid dispatch operation ticket system based on intelligent anti-misoperation method is designed in this paper. First, the overall architecture of dispatch operation ticket system is introduced. Then, the regulations of anti-misoperation are analyzed in detail. And the typical anti-misoperation procedure is provided. Finally, the application and realization of the system is clarified from both hardware configurations and software programming.

Abstract: The paper study the single-phase ground Fault Location. Which analysis neutral non-effectively grounded distribution network transient characteristics of single-phase. and verify the HHT method accuracy that through the actual system simulation of single-phase ground fault experiments .It proposed the fault localization criterion which is based on parameter identification. current single-phase ground fault detection and section targeting methods. The paper proposed the implementation which fault information is incomplete. It is help for theoretical study and power engineering..

Abstract: The access of distributed renewable energy enhances the uncertainty of the distribution network reliability, whereas the distribution network reliability evaluation using existing methods cannot fully reflect the stochastic volatility of islanding power supply and loads. For this reason the approach of active distribution network probabilistic reliability evaluation based on point estimation method was proposed. In the framework of Monte Carlo simulation, the islanding random variable was sampled and processed firstly; then the islanding probabilistic reliability was assessed with a nonlinear transformation method of independent random variables based on point estimate method; finally, system probabilistic reliability indexes can be obtained from the probabilistic superimposing of the results of repeating simulated failures. The simulation on the transformed multi-branch feeder model of the IEEE RBTS Bus6 verifies the validity and accuracy of this assessment approach.

Abstract: A grid-connected inverter control method to analyze dynamic process of large-scale and grid-connected photovoltaic (PV) power station is proposed. The reference values of control variables are composed of maximum power output of the photovoltaic array in the photovoltaic power plant and power factor specified by dispatching. Control strategy of dynamic feedback linearization is adopted. Nonlinear decoupling controller is designed for realizing decoupling control of real-and reactive-power. The cascade PI regulation is proposed to avoid inaccurate parameter estimation which generates the system static error. Simulation is carried out based on the simplified power system with large-scale photovoltaic plant model, the power factor, and solar irradiation, and bus fault are considered for the further research. Its demonstrated that the parameter adjustment of PI controller is simple and convenient, dynamic response of system is transient, and the stability of the inverter control is verified.

Abstract: A parameter identification method for generator speed governor system, which combines decoupling parameter identification and overall recognition with measured data, was proposed in the paper. The method bases on particle swarm optimization, and takes parameter identification as a parameters optimization problem under evaluation function. According to an intelligent optimization algorithms evolutionary strategy, the individual's status is continuously adjusted until the identification system and actual system output error is sufficiently small. Case studies show that the proposed method can be applied to the measured parameters and model validation work.