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Fang C.,Shanghai Municipal Electric Power Company
China International Conference on Electricity Distribution, CICED | Year: 2014

This paper proposes a decision-making method of load interaction mode for demand response by using fine analysis and intelligent decision on the user's load characteristic curve and indexes, which can achieve the effective interaction between grid-side and user-side, provide users with interaction recommendations, and assist the effective implementation of demand response program. Firstly, the intelligent decision-making process of load interaction mode is given. Then, the basic principles of users' typical load form extraction, classification and recognition algorithm are stated. Finally, a calculation example is analysed based on daily load data set from 337 users of a power supply company, whose load characteristics and behaviour features are classified and described. On this basis, a decision tree of load interaction mode is built to realize intelligent load classification and interaction mode matching for new user. Through the calculation example, the correctness of the decision-making method is verified in the aspect of load analysis and interaction mode recognition. © 2014 IEEE. Source


Gan Z.,Shanghai Municipal Electric Power Company | Li Z.-T.,Huazhong University of Science and Technology
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

The islanding operation of distribution generation possibly does harm to the power system, customers and maintenance staffs. Therefore, the operating state of the distributed generation should be monitored appropriately. If the DG is islanded, the islanding must be detected quickly and the DG should be isolated from the main grid. Based on the conventional passive islanding detection methods, of which the typical ones are ROCOF and VS, a novel islanding detection method is proposed based on the advantages of ROCOF and VS and by means of appropriate coordination and setting of the existing ROCOF and VS methods. By virtue of PSCAD/EMTDC, a power system model including DG and integrating into the main grid is set up. A variety of power shortage conditions are simulated and the proposed scheme is verified. Test results demonstrate that this scheme is valid to detect the islanding. Furthermore, the correctness and reliability of the proposed method in various extreme condition are analyzed. Source


Liu J.-T.,China Electric Power Research Institute | Wang Z.-H.,Shanghai Municipal Electric Power Company | Wang K.,China Electric Power Research Institute
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

Two-level voltage source converter (2Level-VSC) with IGBTs directly in series and modular multi-level converter (MMC) are two kinds of the most mainstream converters used in flexible HVDC. Their external features are similar; however, their characteristics of loss are different, which affects their economy and applicable workplace. Based on the device parameters provided by the manufacturer, a general loss calculation model is proposed which is applicable to calculating the losses of both the converters. Through analyzing the working status of devices of the two kinds of converters, loss calculation methods of the two are analyzed in detail. Finally, loss characteristics of 2Level-VSC and MMC are analyzed quantitatively through examples. The results show that loss characteristics of the two kinds of converters are different, and the efficiency of MMC is higher than that of the 2Level-VSC with IGBTs directly in series under different conditions. Source


Xue G.,Shanghai JiaoTong University | Zhang Y.,Shanghai JiaoTong University | Zhu D.,Shanghai Municipal Electric Power Company
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2013

A low-voltage unipolar-type DC microgrid composed of PVA(PhotoVoltaic Array), FC(Fuel Cell) and SC(Super-Capacitor) is studied and its operational control strategy considering the characteristics of DGs is researched. The open-circuit-voltage proportional-coefficient method is used to track the maximum power of PVA. The slope limiter is employed to limit the rate of FC power change for preventing the fuel starvation and improving its performance and lifetime. The sliding mode control is applied to SC for its rapid charging and discharging to stabilize the DC bus voltage. A system model is established with MATLAB/Simulink and the simulative results show that, the proposed control strategy increases the energy utilization efficiency and improves the power quality of system. Source


Ming Y.,Shanghai Municipal Electric Power Company
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010

With the wide spread of HV switch cabinet in the electric system, how to effectively monitor the insulation inside the cabinet to avoid the fault is an important subject which all technicians are confronted with. The principle of the TEV measurement and its application in electric system are introduced to demonstrate the effectiveness of this method in the online test of partial discharge in the HV switch cabinet with the real case. © 2010 Chinese Soc for Elec Eng. Source

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