Hu Z.,Shenzhen Power Supply Bureau |
Wu Q.,Nanjing Southeast University |
Li Y.,Nanjing Southeast University
China International Conference on Electricity Distribution, CICED | Year: 2016
The improvement of smart grid interactive technology provides the basis for the development and utilization of demand-side resources, and the auxiliary frequency regulation by demand-side resources becomes development direction. The electric vehicles (EVs) not only meet the requirements of the society for energy and environmental protection, but also have the characteristics of fast response speed, which is suitable for frequency regulation. This paper establishes the power system frequency response model with the coordination of EVs and GFAs. Based on the model, the paper analyzes the frequency regulation performance with different capacity of EVs and GFAs in single area, and calculates the optimized capacity that can satisfy the requirements. Because centralized control has better response effects than decentralized, this paper focuses on centralized controlled EVs in multi area grid frequency regulation. The control logic contains frequency deviation and tie line power deviation, and sets the dead band to ensure centralized controlled EVs to quit in time. The optimal coordinated capacity, proportion and control strategy are analyzed. The simulation results show that the collaboration of EVs and GFAs has a better effect than only insufficient EVs involved in. Also, centralized controlled EVs can participate in restraining power deviation of tie line in multi area interconnected system, which contributes to the frequency recovery after disturbance. © 2016 IEEE.
Chen C.,Tsinghua University |
Wu W.,Tsinghua University |
Zhang B.,Tsinghua University |
Qin J.,Shenzhen Power Supply Bureau
Dianwang Jishu/Power System Technology | Year: 2012
To improve calculation efficiency of distribution system reliability evaluation, based on deep analysis on failure mode and effects analysis (FMEA), a partitioning method, in which the circuit breakers in distribution network are utilized, is proposed. Taking circuit breakers or section breakers in distribution network as boundary components, the component groups are formed and regarding component groups as basic units, the reliability analysis method is performed. In the proposed method, the impacts of load transferring and power flow constrains are taken into account and the impact of single component on reliability indices of load points is changed into the impacts of overall component groups on load points. The effectiveness of the proposed method is verified by simulation results of wiring of feeder 4 in IEEE RBTS bus 6.
Wang J.,Wuhan University |
Wang K.,Wuhan University |
Yao S.,Shenzhen Power Supply Bureau |
Zhao L.,Shenzhen Power Supply Bureau |
Fang C.,Wuhan University
Gaodianya Jishu/High Voltage Engineering | Year: 2013
In order to study the difference between contaminations on composite insulators and XP-70 insulators, we comparatively observed two kinds of insulators, and selected insulators of uncharged hang on 31 transmission towers which were located in different typical areas in Shenzhen, China. Moreover, we measured the equivalent salt deposit density (ESDD), non-soluble deposit density (NSDD), and the ratio of NSDD to ESDD (rN/E) of insulators contaminated for 2 years, and figured out the difference in characteristics of the upper surface contamination and the lower surface contamination, and the average deposit density between the 2 types of insulators. The results are as follows: 1) For composite insulators, their ESDD on upper surface, ESDD on lower surface, and the average deposit density are about 2.2, 0.3 and 0.5 times of those of XP-70 insulators. 2) For composite insulators, their NSDD on upper surface, NSDD on lower surface, and the average deposit density are about 3.9, 0.9 and 1.4 times of those of XP-70 insulators. 3) The rN/E of composite insulator ranges in 10~30; for XP-70 insulators, the rN/E of the upper surface ranges in 5~25, and the rN/E of the lower surface and the average deposit density ranges in 5~10.
Shi Q.,Zhejiang University |
Xu X.,Zhejiang University |
Zhao Y.,Shenzhen Power Supply Bureau
Dianwang Jishu/Power System Technology | Year: 2016
Different from traditional AC distribution network, DC distribution network is mainly made up of a lot of power electronic devices. To assess reliability of MV DC distribution, reliability models of VSC converter, DC transformer and DC circuit breaker were established to analyzedevice and equipment level redundancy effects on DC distribution system reliability and difference between effects of function failure and insulation failure on DC distribution system reliability. Taking double side power supply DC distribution system for example, influencing factors are quantitatively analyzed and calculated. Comparison results show that equipment level redundancy is better than device level redundancy in improving system reliability, anddifference between function failure and insulation failure mainly influences on reliability calculation of DC distribution system equipped with less DC circuit breakers. © 2016, Power System Technology Press. All right reserved.
Zhou G.,South China University of Technology |
Li X.,South China University of Technology |
Cai Z.,South China University of Technology |
Zhang Y.,South China University of Technology |
Qiu L.,Shenzhen Power Supply Bureau
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010
A same tower multi-parallel line model of phase-splitting parameter is built with EMTDC, which aims to the serious unbalanced current on a Shenzhen 220 kV modernized four-parallel line on the same tower replacing a double-parallel transmission line. Based on study on influenced factors of unbalanced current such as: phase sequence arrangement, line power flow and operation in loop network, suggestions for limiting unbalance current are proposed. Simulation result shows that the strong electromagnetic coupling among each circuits is the primary reason to cause the unbalanced current, and the unbalance of concerned line in the loop network is an important factor as well. Increasing space among lines, reducing the difference of line power flows, adopting negative phase sequence array and loop network open operation under certain conditions are effective measures to limit the unbalance current on a multi-parallel line on the same tower. © 2010 State Grid Electric Power Research Institute Press.
Li Z.,Shenzhen Power Supply Bureau |
Wen X.,University of Sichuan
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011
Phase-c closing failure of a circuit breaker is found during the regular inspection for a 220 kV line protection, which is caused by the poor connection of circuit breaker's closing winding. A protective circuit is designed to add delayed-trip function to the closing circuit, which effectively prevents the burning of closing winding and intermediate relay when closing failure of circuit breaker occurs. The countermeasures are proposed: quickly switch off the operating power; measure the resistance of closing circuit; inspect regularly.
Zhang H.-B.,North China Electrical Power University |
Zhang X.-Y.,North China Electrical Power University |
Tao W.-W.,Shenzhen Power Supply Bureau
Dianwang Jishu/Power System Technology | Year: 2010
Taking active load as the fundamental to draw up initial service restoration scheme, by means of judging the relation between total reserve capacity of bus-tie circuit breakers and total load in power interruption region whether the load connected to the second supporting feeders should be shifted in advance is determined to enlarge the range of service restoration. Using breadth-first search algorithm that adopts the restoration of active load as the fundament for the design of initial restoration scheme, the power supply for the non-faulty interrupted region can be restored uniformly while the power supply path will not be too long. Leading in the concept of reserve capacity correction factor, the service restoration scheme can be automatically modified according to the overload condition of voltage or current. Analysis of case study verifies the feasibility of the proposed algorithm.
Zeng X.-J.,Shenzhen Power Supply Bureau |
Jiang J.-W.,Shenzhen Power Supply Bureau |
Hou J.,Shenzhen Power Supply Bureau
Gaoya Dianqi/High Voltage Apparatus | Year: 2012
Metal-enclosed switchgear rated voltage 10, 35 kV in substations are widely used, which operating security directly affects the supply reliability of substation. Therefore, switchgear operating state monitoring, fault prejudging and reasonable overhaul are the key to guarantee safe and reliable operation of switchgear. The paper explains the principle of TEV and UHF in detecting 10 kV switchgear PD signal respectively. And it also shows the successful application of these two methods in detecting and discovering PD signal on 10 kV 532BCT switchgear of one station. Open and check the equipment, the PD signal has been found on 532BCT disconnecting switch of phase A. This example proves that the combination of both methods is effective in detecting switchgear defect and provides effective methods and basis for finding defects in 10 kV switchgear.
Ma J.,Zhejiang University |
Jiang Q.,Zhejiang University |
Yu P.,Shenzhen Power Supply Bureau |
Duan S.,Shenzhen Power Supply Bureau
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013
With the ever-increasing exhaustion of fossil energy, renewable energy like wind power, photovoltaic as well as energy storage system and electric vehicles is gradually gaining people's attention. However, losses during the conversion are inevitable when new energy sources are connected to the network. By adopting the direct current (DC) distribution technology, the cost of conversion can be appreciably reduced. In addition, DC distribution network safe, economical, and highly efficient operation can be realized by designing the converter commands rationally and effectively. The characteristics and advantages of the distribution network are described first, followed by a brief account of its energy structure. Then the latest progress in two aspects, namely, the energy optimizing management technology and the coordinated control strategy among converters based on energy management optimization commands is summarized. In the end, some directions that have yet to be further improved and perfected are discussed. © Right.
Hong H.,Zhejiang University |
Jiang Q.,Zhejiang University |
Yan Y.,Shenzhen Power Supply Bureau
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013
This paper presents a novel model predictive control (MPC) based coordinated control algorithm for the battery energy storage system (BESS) in smoothing out wind power fluctuations. The goal of the method is to minimize the power output of BESS in the next prediction horizon. The variety of constraints is considered, such as the 1-minute and 30-minute fluctuation mitigation requirements (FMR), the BESS maximum power limitation and energy constraint. When the synthetic power output fails to satisfy the proposed FMR, the constraint softening adjustment technology is adopted while taking into account the expected goals to obtain satisfactory optimization results. What is more, the state-of-charge (SOC) feed back control strategy is proposed to regulate the SOC of the BESS within its proper range. Furthermore, an adaptive penalty function of roughness is developed to further smooth the combined output, lower the storage capacity and improve the economy of system operation. Simulation studies demonstrate that, compared with the low-pass-filter-based algorithms, the proposed MPC-based algorithm needs lower power rating and storage capacity. Also, it facilitates engineering realization for its simple algorithm and small computation workload. © 2013 State Grid Electric Power Research Institute Press.