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Zhou W.,Dalian University of Technology | Sun H.,Dalian University of Technology | Gu H.,Dalian University of Technology | Chen X.-D.,Liaoning Electric Power Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Large-scale integration of wind power generators into power grid brings severe challenges to power system economic dispatch due to its stochastic volatility. Economic dispatch including wind farm is elaborated and analyzed from the aspects of modeling and solving methods. According to different treatments of wind speed/wind power uncertainties, the economic dispatch models including wind farm are discussed through the deterministic modeling method, fuzzy modeling method and probabilistic modeling method. Furthermore, the issues on reserve and risk dispatch management in modeling resulted from wind power are introduced. Solving methods are divided into certainty and uncertainty methods corresponding to the classification characteristics of optimization model. Finally, some suggestions are given for further studies on the economic dispatch of power systems including large-scale grid-connected wind farm.

Yan X.,Shenyang University of Technology | Sun Y.,TEBA Shenyang Transformer Group Co. | Yu C.,Liaoning Electric Power Corporation | Xie D.,Shenyang University of Technology
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2014

Inverted current transformer is very different from traditional production on design and manufacture. Insulation fault often occurred in the early application. The electric field calculating model which combined FEM with analytical method is proposed in this paper. The electric field distribution in main insulation of actual oil-immersed inverted current transformer is been analyzed using this model, and the main factors which affected the insulation performance are researched. To reduce the maximum electric field strength, the main insulation structure of current transformer is optimized using radial basic function (RBF) neural network dynamic response model and genetic algorithm. After optimization, the electric field strength in main insulation is reduced, and the electric field distribution is become more homogeneous. The optimized result can instruct the design and manufacture of oil-immersed inverted current transformers.

Jin E.-S.,Northeast Dianli University | Song X.-G.,Northeast Dianli University | Dong H.,Liaoning Electric Power Corporation | Li X.-N.,Northeast Dianli University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

In order to solve the problem of misjudgment in the flow transferring overload identification of protection-load shedding when the power swing occurs, this paper specifically analyses the electrical characteristics of the overload, the power swings and the fault to identify the differences among the three characteristics in measured impedance angle, measuring the rate of change in impedance, sequence component, and protection action situations, formulating a new flow transferring overload identification method. After starting backup protection, firstly it can distinguish failure with sequence component and protection action situation, then distinguish overload and swings with the rate of change in impedance; or firstly distinguish swings with the rate of change in impedance, then discern overload and fault with measured impedance angle. Example analysis results show that it can identify the overload and prevent a misjudgment when the system occur power swings, proving the correctness and validity of the method.

Yan G.,Northeast Dianli University | Zhu X.,Northeast Dianli University | Li J.,Northeast Dianli University | Mu G.,Northeast Dianli University | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

A control strategy based on the principle of low-pass filtering for the hybrid energy storage system (HESS) composed of battery and supercapacitor is proposed. The reference output power of the battery is determined according to the principle of moving average. The main part of wind power fluctuation is smoothed by the battery, while the remaining component with high frequency is smoothed by the supercapacitor. By assessing the charging and discharging status of the battery, a performance evaluation method with intrinsic operation life measurement and calculation for the HESS control strategy is developed. Based on the actual operation data of a wind farm, the effect of the cut-off frequency of the low-pass filter and the time scale of moving average on the operation life of the battery in HESS is analyzed by simulation. Besides, reference values of relevant control parameters are given to prolong the operation life of the battery. Research results provide a theoretical reference to the application of HESS. © 2013 State Grid Electric Power Research Institute Press.

Liu D.,NARI Group | Wang K.,Liaoning Electric Power Corporation | Hu S.,Anshan Electrical Power Corporation | Zhang S.,Anshan Electrical Power Corporation | And 2 more authors.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012

The PCS integrated protection, which is successfully applied in a 220 kV substation, adopts the embedded hardware and distributed software. The protection, measurement and control functions of a bay are integrated in one DSP card and can be flexibly extended. At 220 kV level, two integrated line protections and one integrated unit protection are equipped for the protection of all lines, links, buses and transformers. At 66 kV level, four integrated low-voltage protections are equipped for the protection of all lines, reactors and capacitors. The redundant IEC61850-9-2/GOOSE-based dual-network is designed at process level while the special peer-to-peer synchronization technology is adopted for the differential protections at bay level.

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