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Huang Y.,Tsinghua University | Hu W.,Tsinghua University | Min Y.,Tsinghua University | Luo W.,Liaoning Electric Power Corporation | And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014

This paper proposed a multi-timescale coordinative scheduling method and a coordinative rolling scheduling plan model for large-scale wind-storage combined generation power systems. A two-stage model was adopted to formulate the multi-objective optimization model and carried out the hierarchical coordination of power systems with large-scale wind power integration. The first stage optimization minimized the wind power curtailment and load curtailment with the coordinative scheduling of energy storage systems and conventional thermal units. The second stage optimization was allocation of power generation schedules of different wind farms as well as thermal units. IEEE 30-bus system with three actual wind farms was used for verification purpose. It is shown that the wind curtailment and operation costs are both reduced by adopting the proposed intra-day rolling coordinative scheduling dispatch with ultra-short-term wind forecasts updated more frequently. ©2014 Chinese Society for Electrical Engineering

Lu Q.,Tsinghua University | Hu W.,Tsinghua University | Zheng L.,Tsinghua University | Min Y.,Tsinghua University | And 4 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

The rapid development of battery energy storage technology has provided a new solution for integrating large scale wind power; however, the accurate simulation model for battery energy storage system (BESS) in power system application has not been developed yet. In this paper, a BESS model based on Thevenin circuit was developed. In this model, the model parameters fitting method based on experimental data was proposed, and the influences of state of charge (SOC) and charged/discharged current on model parameters were taken into account. Further, the critical factors in various application scenarios were analyzed to facilitate the proposed model to be feasible in multiple time scales. The effectiveness of the presented model was verified by the measured voltage and current data. Finally, the model was applied to alleviate low frequency wind power volatility to test the control effect of BESS, and the advantages and disadvantages of different models and their impacts on BESS capacity allocation was further discussed.

Liu D.,NARI Group | Wang K.,Liaoning Electric Power Corporation | Hu S.,Anshan Electrical Power Company | Zhang S.,Anshan Electrical Power Company | 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.

Zhang Y.,Liaoning Electric Power Corporation | Gao K.,Liaoning Electric Power Corporation | Qu Z.,Liaoning Electric Power Corporation
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

In view of the incapability of the current evaluation method of primary frequency modulation in accurately reflecting the effect of primary frequency modulation, an evaluation method of primary frequency modulation effect based on the characteristics of unit output power curve variation is proposed. The characteristics the unit primary frequency modulation should have are discussed, and based on this concept, four indices are presented to evaluate the performance of unit primary frequency modulation. Then problems such as the essential factors of the effective disturbance, the impact and treatment method of automation generation control on primary frequency modulation assessment are treated. The proposed method is suitable for power grids with different capacities and different load characteristics, and is applied to the unit primary frequency modulation assessment in Liaoning Power Grid. © 2012 State Grid Electric Power Research Institute Press.

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.

Zheng X.,Liaoning Electric Power Corporation | Tao Y.,Liaoning Electric Power Corporation
APAP 2011 - Proceedings: 2011 International Conference on Advanced Power System Automation and Protection | Year: 2011

Due to strong blizzard, a wide range of blackout struck Liaoning power grid on March 4, 2007. Under the circumstance of multiple transmission lines struck by faults combining with the varying of system run mode, with the help of intelligent relay protection fault system (I-POFAS), WFl2010 fault travelling wave range finder splendidly achieve the commission including analyzing considerable amount of data in time-sequence within short time, supervising fault position in real-time, supporting dispatcher with real-time data. © 2011 IEEE.

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.

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.

Li N.,Northeastern University China | Li L.,Northeastern University China | Yang D.,Northeastern University China | Zhao Y.,Northeastern University China | Yang Y.,Liaoning Electric Power Corporation
Proceedings - 4th International Workshop on Chaos-Fractals Theories and Applications, IWCFTA 2011 | Year: 2011

This paper is concerned with the weak signal detection based on the Duffing chaotic model. To solve the problem of low SNR in traditional testing methods, a method of detecting weak signals based on the Duffing oscillator coupled synchronization is proposed. Through the chaos theory and simulations, the characteristics of the coupled Duffing oscillator, the SNR threshold of the weak signal detection methods based on the coupled Duffing oscillator and the advantages of the coupled synchronization method are analyzed. At last, the effectiveness of the proposed method is shown by a simulation example. © 2011 IEEE.

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.

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