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Sun G.,Hohai University | Li Y.,Hohai University | Xiang Y.,Hohai University | Yang Y.,Yancheng Power Supply Company | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

Large-scale wind power integrates into power grid. The fluctuant and intermittent nature of wind speed greatly challenges the conventional dynamic optimal power flow. Considering randomness as well as temporal and spatial correlation of wind speed, a dynamic stochastic optimal power flow model of wind integrated power system based on chance constrained programming was built. Based on primal-dual decomposed interior point method, an optimal dispatching was got through the deterministic optimal power flow. The dynamic probabilistic power flow based on cumulant method considering correlation was used to calculate probability distributions of state variables. New upper and lower bounds to the corresponding variables were formed if chance constraints were violated. The iteration terminated until a final optimal dispatching was found with all the chance constraints satisfied. The precision and efficiency of the algorithm is verified through the stimulation of modified IEEE14-bus system. On such basis, the impacts of random branch outages and wind speed correlation on power system operation characteristic are investigated. © 2015 Chin. Soc. for Elec. Eng.


Li Y.,Hohai University | Sun G.,Hohai University | Yang Y.,Yancheng Power Supply Company | Huang W.,Yancheng Power Supply Company | And 2 more authors.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2015

The grid-connection of offshore wind farm impacts the OPF (Optimal Power Flow) of power system due to the uncertainty of offshore wind speed and a probabilistic optimal power flow calculation model of AC/DC system with offshore wind farm connected to grid via VSC-HVDC (Voltage Source Converter based High Voltage Direct Current) is proposed. The nonparametric kernel density estimation is adopted to fit the distribution of offshore wind speed and the steady-state models of offshore wind farm and VSC-HVDC are built. The standard normal distribution samples are obtained by Latin hypercube sampling and the input variable samples with correlation are obtained based on the equivalent possibility transformation and Nataf transformation. The primal-dual interior-point method is applied in the OPF calculation to obtain the output variable samples and the statistical method is used to obtain its numeric characteristics and probability distribution. The simulative results of IEEE 14-bus system and IEEE 118-bus system verify the correctness and efficiency of the proposed method. ©, 2015, Electric Power Automation Equipment Press. All right reserved.


Chen S.,Hohai University | Wei Z.,Hohai University | Guo X.,Yancheng Power Supply Company | Liu X.,Yancheng Power Supply Company | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2015

A new method for power system multi-area distributed state estimation considering hybrid supervisory control and data acquisition (SCADA) system and phasor measurement unit (PMU) measurement is presented. First, it is assumed that the measurement model is linear, the network is decomposed by the extended sub-areas including the border buses of neighboring sub-areas. Then the problem is solved by the alternating direction method of multipliers (ADMM), a method widely used in distributed optimization. Only the states of border buses need to be exchanged among nearby areas without central coordination, thus retaining the independence of each sub-area. Afterwards, based on bilinear theory integrating hybrid SCADA system and PMU measurements, the traditional nonlinear state estimation is transformed into a three-stage problem. The first and third stage simply solve the linear state estimation problem during which ADMM is applied to solving the distributed problem, the second stage is one-step nonlinear transform in which each sub-area can perform this nonlinear transformation independently. The combination of bilinear theory and ADMM ensures the convergence of distributed state estimation while improving computational efficiency. Finally, numerical tests have verified the advantage of the proposal over existing methods in many aspects. © 2015 Automation of Electric Power Systems Press.


Zhang J.,NARI Group | Zhang J.,State Grid Electric Power Research Institute of China | Zhou H.,Yancheng Power Supply Company | Qian J.,NARI Group | Qian J.,State Grid Electric Power Research Institute of China
APAP 2011 - Proceedings: 2011 International Conference on Advanced Power System Automation and Protection | Year: 2011

Considering the deficiency in traveling wave fault location and digital fault location, the paper proposes a two-terminal fault location algorithm with unsynchronized sampling based on genetic algorithm. Location is not affected by pseudo roots, false resistance, system impedance or types of faults. Besides, strategy for selecting initial interval adaptively is adopted to accelerate convergence speed greatly. The simulation results show that this algorithm has fast convergence and high accuracy of location with any iteration point on the line. The accuracy meets the actual requirement and this method has high practical value. © 2011 IEEE.


Sun H.-F.,Yancheng Power Supply Company | Zhang Y.,Yancheng Power Supply Company | Sun Z.-H.,Yancheng Power Supply Company | Ji N.,Yancheng Power Supply Company | And 3 more authors.
Gaoya Dianqi/High Voltage Apparatus | Year: 2010

A circuit model of grading ring's paint film in series with a grading capacitor is established. The analysis of grading capacitor's dielectric loss via the model is in accordance with the measurement, which verifies the validity of the model. The calculation result indicates that paint film has large capacitance and dielectric loss. Thus the measuring line should connect with the clean point of grading capacitor to avoid effect of paint film in measurement of grading capacitor's dielectric loss.

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