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Chen R.-F.,Tsinghua University | Huang S.-W.,Tsinghua University | Wang Z.-W.,Tsinghua University | Wu D.,Xuancheng Power Supply Company | And 2 more authors.
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2015

Dealing with the special features of the micro-grid such as small short-circuit current, bidirectonal power flow, and high proportion for energy storage system, the protection of the PV based micro-grid should be carefully designed to guarantee the reliable operation of micro-grid. A hierarchical comprehensive protection system was proposed to minimize the load loss of the micro-grid when faults occur. The protection system has three main functions, including relay protection scheme based on phase and magnitude comparison, fast storage output regulation and emergency control. A test micro-grid with energy storage system was setup in PSCAD/EMTDC, based on which simulations were carried out for various faults situations. By comparing the performance of the proposed protection system and traditional protection scheme, the effectiveness and practicality of the proposed hierarchical comprehensive protection system was verified. ©, 2015, Editorial Department of Electric Machines and Control. All right reserved.


Zhao M.,Tsinghua University | Huang S.W.,Tsinghua University | Wu X.Y.,Tsinghua University | Huang X.Q.,Guangxi Power Grid Corporation | Xu Q.B.,Xuancheng Power Supply Company
Advanced Materials Research | Year: 2013

A standard is of great importance to microgrid application and development. So far, there is no published standard specifically for microgrids in China except for the Guangxi provincial standard, which is drafted by the authors. This paper focuses on the lessons that the drafters have learned from the standard establishment. The background of making such a standard is introduced first, and its purposes are clarified, as well as the difficulties in standard drafting. Then the structure of this standard is explained, and one technical specification is detailed as an example. Further studies on planning and design of microgrids, multi-microgrids integration and limitations of this standard are discussed. This work can provide reference for establishing a national microgrid standard, thus can stimulate the standardization of microgrids in China and promote their application. © (2013) Trans Tech Publications, Switzerland.


Ma J.,North China Electrical Power University | Ye D.,Zhangzhou Electrical Power Bureau | Wang T.,North China Electrical Power University | Li J.,Xuancheng Power Supply Company | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011

In the scenario of network configuration variation, a novel method for updating the minimum break point set (MBPS) is proposed based on phantom break point set (PBPS). According to static network topology, the network original information base (NOIB) can be obtained, which contains the original relay-incidence matrix (RIM), MBPS, relay relative sequence table (RRST), and the incidence elements of break points (BPs). When the network topology is varied, the type of variation is identified first and the PBPS is determined based on the NOIB. Then, the RIM is reconstructed and the BPs added or to be deleted are calculated using part of the elements of the reconstructed RIM. The final MBPS of the new network is obtained after the commutative BPs or new terminal BPs are verified. Case study demonstrates the method proposed can obtain the final MBPS of the whole system without the knowledge of any circuit loops. And MBPS can be updated rapidly by modifying only a few elements. Furthermore, this method is applicable to a lot of types of variation of the network configuration with less computational burden. © 2011 State Grid Electric Power Research Institute Press.


Zheng T.-W.,Tsinghua University | Liu F.,Tsinghua University | Xiao X.-Y.,University of Sichuan | Zhou Y.-R.,Xuancheng Power Supply Company | Mei S.-W.,Tsinghua University
Dianji yu Kongzhi Xuebao/Electric Machines and Control | Year: 2013

Lithium-battery energy storage system (BESS) is characterized by nonlinearity, time varying and strong coupling, greatly challenging the control system design, especially when model inaccuracy and external disturbances are taken account in. Suggests designing the charging/discharging control of BESS based on the active disturbance rejection control (ADRC) technique. First, establishing the ADRC model of BESS; Then, proposing the general methodology of ADRC design for BESS; At last, providing a double-closed-loop ADRC control strategy for the charging and discharging of BESS. And comparing the performances of the conventional PI control and the proposed ADRC control by carrying simulations on PSCAD/EMTDC platform. Simulation results manifest that the proposed double-closed-loop ADRC control endows BESS better dynamic performance and stronger ability to attenuate disturbances under different conditions, such as variation of charging voltage, charging current or system parameters.


Lu J.,Xuancheng Power Supply Company | Lu J.,Guangxi University | Li X.,Guangxi University | Huang W.,Guangxi University | And 3 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

To study how the linear optimal comprehensive controller of Static Synchronous Series Compensator (SSSC) and excitation to suppress sub-synchronous resonance in the disturbance situations of mechanical and electrical. A classical theory of linear optimal control theory and sub-time optimal control weighting matrix method are proposed. Compared to no controller and the SSSC optimal controller (LOSC), the system eigenvalue parameter analysis shows that LOSEC can improve system damping ratio and operational stability. Finally, the electromagnetic transient model of single machine infinite bus power system including SSSC is established by Matlab/Simulink. The simulation shows that under the short-circuit disturbance, using LOSEC method to suppress sub-synchronous resonance effect is more significant. ©, 2015, Power System Protection and Control Press. All right reserved.


Ma J.,North China Electrical Power University | Li J.-L.,Chengdu Electric Power Bureau | Li J.-H.,Xuancheng Power Supply Company | Yang Q.-X.,North China Electrical Power University | Wang Z.-P.,North China Electrical Power University
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

A novel wide-area fault location algorithm is proposed. Under the normal condition of the power system, network correlation coefficient matrix is formed. After the fault occurs, by analyzing fault model, value of location function at each search step on each branch is calculated. And fault location is determined on this basis. This method does not modify network matrix during fault location process, and can locate fault branch and fault distance simultaneously. It has less calculation burden and is easy to be realized. The simulation results based on PSCAD verify the validity and feasibility of this method.


Ma J.,North China Electrical Power University | Li J.,Chengdu Electric Power Bureau | Ye D.,North China Electrical Power University | Wang Z.,North China Electrical Power University | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

A novel wide-area back-up protection principle utilizing fault matching degree (FMD) is presented. During normal operation of the power system, the protection associated area (PAA) is formed based on the placement of phasor measurement units (PMUs) and the network topology. When fault occurs, by calculating the fault steady state component of differential current within each PAA, the fault associated area (FAA) is determined. The FMD therein is then calculated to precisely locate the fault. Verification by simulation with a 10-generator 39-bus system using distributed parameters shows that the method is free from the influence of the operation condition of the power system, and is capable of rapid, reliable, and sensitive fault location under the limited PMU measuring points condition. Furthermore, it is not necessary to modify the network matrix in the fault location process. The calculation burden is not heavy and the principle is easy to implement. ©2010 State Grid Electric Power Research Institute Press.


Zhang L.,China University of Petroleum - East China | Kang W.,China University of Petroleum - East China | Jia L.,China University of Petroleum - East China | Zhao M.,Xuancheng Power Supply Company | Xu R.,Xuancheng Power Supply Company
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2010

The battery test requests its system converter to output excellent charging/discharging current. According to the special request, this paper designed the main circuit of current mode PWM converter, and put forward a loop-locked control method based on dq coordinate conversion to SVPWM converters in the power accumulator battery testing system. The set can output low ripple and fast response testing current in a wide adjustable range and operates in high power factor. It delivers the power accumulator's energy to the power grid without harmonic solutions and increases the transform efficiency by SVPWM and get high power factor and high dynamic response quality by dq coordinate conversion. ©2010 IEEE.

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