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Shenzhen, China

Sun G.,Beijing Sifang Automation Co | Shi B.,Beijing Sifang Automation Co | Zhao Y.,Shenzhen Power Supply Co. | Li S.,North China Electrical Power University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

A protection configuration strategy and fault location method of the demonstration project of flexible DC distribution system in Shenzhen is studied. Firstly, focusing on the topology structure of the project, the protection area of DC distribution network is divided. Secondly, an overall protection configuration strategy is presented considering MMC and the system's faulty characteristics. Thirdly, as the new feature of the load and micro grid being connected with the DC line with "T" type, the protection configuration and fault location method of DC line single-pole fault, double-pole fault and broken line fault is proposed. Lastly, the simulation model of MMC based DC distribution grid is built on PSCAD/EMTDC, and the simulation results verify the effectiveness of the protection configuration strategy and the correctness of the fault location method. © 2015, Power System Protection and Control Press. All right reserved. Source

Ming Z.,North China Electrical Power University | Shaojie O.,North China Electrical Power University | Hui S.,Shenzhen Power Supply Co. | Yujian G.,North China Electrical Power University | Qiqi Q.,North China Electrical Power University
Renewable and Sustainable Energy Reviews | Year: 2015

As a good power supplement form of super power and large-scale energy base, distributed energy has the characteristics of less investment and flexible power generation. Facing with the double pressure of the sustainable development of energy use and environmental protection, it has become an efficient solution to meet the demand of load growth, reduce environmental pollution and improve the comprehensive utilization of energy and the reliability of power supply. However, the development of distributed energy starts relatively late in China and confronts many difficulties. So this paper analyzes the present development situation and existing problems of the distributed energy in China. Then it elaborates from the aspects of policies and regulations, technical specifications, price policy and grid-interconnection codes. At last, this paper puts forward relevant policy suggestions of the guarantee mechanism of distributed energy. This paper argues that, with the attention of the development of distributed energy increasing, a series of policies to promote the construction and interconnection of distributed energy will be introduced, and distributed energy will get scaled development in China. © 2015 Elsevier Ltd. All rights reserved. Source

Pan Z.,Nanjing Southeast University | Gao C.,Nanjing Southeast University | Liu S.,Shenzhen Power Supply Co.
Dianwang Jishu/Power System Technology | Year: 2016

In order to promote electric vehicle development coordinated with power grid, this paper proposed a charging and discharging dispatch model of electric vehicles based on demand side discharge bidding. In day-ahead scheduling, electric company published time periods need to curtail load. According to prediction of electric vehicle users' behavior characteristics, load aggregator took maximum discharging capacity as goal to predict controllable capacity, and then participated in demand side discharge bidding. Electric company devoted to minimize load dispatching cost based on outputs and biddings of load aggregators. In real-time scheduling, load aggregator was aimed at maximizing its benefit through optimizing charging and discharging dispatch of electric vehicles. It could not only meet electric vehicle charging demand, but also reduce charging cost and dispatching deviation. Simulation result showed that the proposed dispatch model could play a role in peak load shifting. Prediction accuracy analysis could provide guidance for bidding decision of load aggregator. © 2016, Power System Technology Press. All right reserved. Source

Zhao B.,Tsinghua University | Song Q.,Tsinghua University | Liu W.,Tsinghua University | Zhao Y.,Shenzhen Power Supply Co.
IEEE Transactions on Power Electronics | Year: 2016

This paper presents the transient dc bias and the current impact effects of a high-frequency-isolated bidirectional dc-dc converter (IBDC) in practice because the theoretical premise in the steady process cannot be satisfied strictly in the transient process. The transient characterizations of IBDC under the steady phase-shift (SPS) strategy are analyzed comprehensively, and the corresponding model is modified for all of the transient processes in the same and different power flows. Due to the existence of the dc bias, the current model in the transient process is different from the traditional model in the steady process, and the models are different with different operating conditions. On this basis, a transient phase-shift (TPS) strategy is proposed to improve the transient performance of the SPS strategy. Unlike in the SPS strategy, the voltages of the transformer are symmetrical in the TPS strategy, which causes that the voltage-time product of the transformer voltages is zero during a switching period, then eliminates the transient dc bias and improves the current impact, and further increases the response speed of the transient process effectively. Finally, comprehensive experiments verify the theoretical analysis. © 2015 IEEE. Source

Ding D.,Sichuan Electric Power Research Institute | Ding D.,Tsinghua University | Gao W.,Tsinghua University | Yao S.,Shenzhen Power Supply Co. | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013

The understanding of the excitation mechanism of ultra high frequency (UHF) electromagnetic waves (EW) is essential for applying UHF method to partial discharge (PD) detection. Since the EW induced by PD in gas insulated switchgear (GIS) contains not only transverse electromagnetic (TEM) wave, but also high-order transverse electric (TE) and high-order transverse magnetic (TM) waves, we analyzed the proportions between the TEM wave and the high order waves, as well as the influence of the PD position on this proportion, using the finite different time domain (FDTD) method. According to the unique characteristics of the waves, they are separated only approximately. It is found that the high-order mode is the main component, more than 70%, of the electric field around the enclosure of GIS, and that with the increasing distance between PD source and inner conductors, the low frequency (below about 800 MHz) component of EW decreases, but the high frequency component (above 1 GHz) increases, meanwhile the proportion of high-order components in EW could reach 77% from 70%. It concluded that the closer the PD source to the enclosure is, the easier high order EW may be excited. Source

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