Liu D.,Shandong University |
Li X.,Yanjin Power Supply Bureau |
Zhao H.,Yanjin Power Supply Bureau |
Zhong S.,Qingdao Power Supply Company
Dianwang Jishu/Power System Technology | Year: 2011
This paper, based on the platform of dispatching automation system, introduced the frame work, function modules and main characteristics of on-line stability and energy-saving comprehensive monitoring and early-warning system. Based on real-time collected data, stability and energy-saving comprehensive monitoring and early-warning system (SEMW) can display core power system state information, such as stability mode, stability index, the relative relations between stability and active-power loss as well as reactive-power compensation levels, and so on. Through this, the dispatcher can clearly understand power system running situation. SEMW is specialized in quick location of hidden power security dangers, automatic intelligent control and voice warning. With engineering implementation, SEMW can significantly improve the on-line stability and energy-saving comprehensive monitoring and early-warning capability, as well as realize the smart grid dispatching.
An Y.,Wuhan University |
Wen X.,Wuhan University |
Zhang T.,Qingdao Power Supply Company |
Ma K.,Ningxia Electrical Power Research Institute |
And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2013
To ensure the safety of substation expanding and new shunt reactor operation, we researched the overvoltage of shunt reactor during switching-on process by theoretical analysis, tests and simulations, and theoretically analyzed the reasons of the overvoltage from two aspects, namely, mechanism of transient prebreakdown of SF6 breaker and reflection and refraction of wave. Moreover, we established a SF6 breaker prebreakdown model in ATP-EMTP to simulate the field tests. Tests and simulation results showed that the specific overvoltage on the reactor during process of switching-on could reach 4.0. However, simulation results showed that, with resistance and capacitance absorption equipment, the specific overvoltage could be decreased to 1.68 in the same condition. Simulation results indicated that the absorption equipment could be an effective measure for overvoltage limitation, which not only decreased the systematic overvoltage but also restrained systematic harmonics. The pre-breakdown phenomenon introduced in this paper could be referred for protection of shunt reactor operation in substations.
Cao M.,Qingdao University |
Wu X.,Qingdao University |
Song H.,Qingdao Power Supply Company |
Liu Y.,Qingdao Power Supply Company
APAP 2011 - Proceedings: 2011 International Conference on Advanced Power System Automation and Protection | Year: 2011
Network reconfiguration in power system is an important stage in the process of the power system black start. The important issues in this stage are to determine the restoration sequence of target nodes, and to optimize the restoration paths for the node restoration sequence. Both of the two issues are considered as a whole in this paper. Some electrical indexes, such as line operating time, line operating costs, and cranking unit number, are introduced to reflect the electrical characteristics of power system network. At the same time, based on the topological characteristics of power system network, a topological index, node importance degree is introduced here to solve the optimization problem. Meanwhile, the classic Dijkstra algorithm and the genetic algorithm are employed to search the global optimal restoration sequence of target nodes and node restoration paths. The numerical tests on the IEEE 30 system validates the strategy proposed in this paper. © 2011 IEEE.
Zhou C.,Shandong University |
Tian L.,Shandong University |
Hou Y.,Shandong University |
Qi W.,Qingdao Power Supply Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012
A new method based on optimal voltage sag monitoring program is proposed to locate any type of fault on the transmission line when only voltage sag data are available. Firstly a 0-1 linear programming-based model is built to solve the problem of optimization allocation. The object of the optimization model is to minimize the number of the monitoring buses and the key constraint is to guarantee the observability of the whole system considering any type of fault (balanced or unbalanced). Then based on the optimal monitoring program, the fault position and faulted transmission line are estimated by implementing the least squares method. In this estimation, only the voltage sag magnitudes recorded at the limited optimal monitoring buses are available measurements. The performance of the proposed method is illustrated in an IEEE 39-bus test system, and the validity of the method is testified. ©2012 State Grid Electric Power Research Institute Press.
Sun Y.,Shandong University |
Chao W.,Qingdao Power Supply Company
Advanced Materials Research | Year: 2012
This paper first gives out the harmonic coupled equivalent model for the Thyristor Controlled Reactors (TCRs) and the converter. Then, the harmonic generating characteristics of the TCRs and the converter are investigated based on the proposed model. With the help of the equivalent model, the impact of each harmonic contribution component is quantified. Moreover, based on the characteristics analysis of the model, two simplified model are proposed which are useful for simplifying the harmonic analysis of systems with TCRs and converters.
Xu X.,Shandong University |
Zhang H.,Shandong University |
Xu Q.,Qingdao Power Supply Company
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2014
User-defined modeling helps a lot in enhancing the flexibility of power system numerical simulation. A user-defined modeling scheme is proposed to extend power system numerical simulation capabilities. It is implemented with MATLAB, which can fully use the numerical calculation and visual modeling functions of MATLAB. Therefore, the simulation and analysis abilities of power system simulation software package can be effectively enhanced. The case shows the feasibility and effectiveness of this approach. © 2014 IEEE.
Peng M.,North China Electrical Power University |
Zhao C.,North China Electrical Power University |
Liu X.,Qingdao Power Supply Company |
Guo C.,North China Electrical Power University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2014
The capacitor voltage balancing of modular multilevel converter (MMC) determines the stable operation of MMC based high voltage direct current (HVDC) transmission system. When the number of sub-modules (SMs) is excessive, it requires a large amount of computation time, which poses a challenge to the design of the physical controller. To solve this problem, this paper proposed an improved capacitor voltage balancing method. The improved method grouped the SMs to reduce the computing quantity of sorting the capacitor voltages, and maintained the voltage balancing between groups by adopting the voltage balancing algorithm between groups. Then the optimization method inspired by the prime factorization principle is put forward. A MMC-HVDC model was developed in RT-Lab. The simulation results show that the improved method and the optimization method can both reduce the amount of computation and improve the simulation speed significantly with the balancing of capacitor voltages. All those results verify the effectiveness and feasibility of the improved method and the optimization method. © 2014 Chin. Soc. for Elec. Eng..
Li Z.,Shandong University |
Han X.,Shandong University |
Yang M.,Shandong University |
Zhong S.,Qingdao Power Supply Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011
Wind power is stochastic and is difficult to reflect its characteristics only by its expectation. Consequently the power grid risk is difficult to analyze. A new model based on the quantile regression analysis theory is proposed, in which a regression function is selected self-adaptively through support vector machine in each wind power fluctuation interval, and the interior point method is adopted to solve this model. The future wind power fluctuation interval analysis is realized. At last, the proposed method is used to analyze the output power of a wind farm in Yantai area power grid. The results show that the proposed method can give a better all-around description of wind power uncertainty, and provides a basis for the risk decision-making in the power system dispatch and control. © 2011 State Grid Electric Power Research Institute Press.
Wang Z.,North China Electrical Power University |
Xu Q.,Qingdao Power Supply Company
DRPT 2011 - 2011 4th International Conference on Electric Utility Deregulation and Restructuring and Power Technologies | Year: 2011
Due to the planning, producing, operating and administrating procedure were not been tightly connected, a great amount waste of investment will be caused in traditional power system's development and construction. So, the development of power system needs to be considered comprehensively in the perspective of the improving of power supply reliability and the economical of power system's construction. This paper proposed a two-stage distribution system planning method based on the demand above. This method broke through the limitations of the traditional planning which can only consider the simple reliability demand such as the N-1 principle, and specified it into every stage of the planning. Besides, it could comprehensively optimize the network structure, equipment condition, technology application and administration method to make the project more scientific and feasible, which will effectively improve the power supply reliability and the economical of power system's construction. © 2011 IEEE.
Li W.-S.,Qingdao Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010
Through the application of 220 kV GIS electronic current and voltage transformers in Wushan digital substation, this paper introduces its configuration, reference standard, principle and structure, key technologies of the active electronic transformer, and several issues of applying electronic transformers. This paper focuses on electronic transformer synchronization issues and synchronization methods, and the impact of synchronization on the line differential protection. Finally, it is pointed out that the use of electronic transformer will bring far-reaching changes and impact on domestic substation automation and management. It will improve the security and reliability of the device and achieve interoperability in technology and will reduce the investment and the overall cost of substations life cycle in economy.