YAN Lu-guang^1,2, XIAO Li-ye^1,2, LIN Liang-zhen^!,2, DAI Shao-tao^!,2

(1. Key Laboratory of Applied Superconductivity, Chinese Academy of Sciences, Beijing 100190, China; 2. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China)

Abstract: High-temperature superconducting power transmission has a number of important advantages. As a promising new technology, it demands to vigorously promote the related works on high-temperature superconducting power transmission and unified planning and careful deployment. In this paper we suggest that "high-voltage, long-distance, high-capacity high-temperature superconducting power transmission" as a national major projects included in the national plan.

Distributed dynamic power flow calculation based on decomposition and coordination

HUANG Shao-wei, CHEN Ying, SHEN Chen, MEI Sheng-wei

（State Key Lab of Power Systems, Dept. of Elec. Eng., Tsinghua University, Beijing, 100084, China）

Abstract: With the considerations of the dynamic characteristics of loads and generators, the dynamic power flow is one of the most important functions of EMS and DTS. To achieve the on-line power flow analysis of the multi-area interconnected power systems, a new algorithm of the distributed dynamic power flow is proposed in this work. By setting up the implicit boundary equations, the unified power flow of the whole power system is modeled in the decomposition and coordination manner, which can handle the power balance and distribution of imbalance power at the same time. Then, a Jacobian-Free Newton-GMRES method is used to solve the boundary equations, which requires the simple interfaces of the data exchanges during the coordination procedures. Test results in wide area network communication environment show that the proposed algorithm can archive such high-performances both on the computation and communication aspects that it is practical and feasible for the online power flow analysis applications.

Key words: dynamic power flow; distributed computing; decomposition and coordination

DING Xin-ping¹, LIU Jian², LU Yan¹, ZHANG Min¹

(1. Automation Engineering College, Qingdao Technological University, Qingdao 266520, China;

2. Beijing CLP Hisatsune Technology Co., Ltd, Beijing 100085, China)

Abstract: A PID controller for dc-link boost voltage in Z-source inverter has been presented. With this technique a constant Z-network capacitor voltage can be achieved with an excellent transient performance which enhances the rejection of disturbance, including the input voltage ripple and load current variation, and have good ride-through for voltage-sags. Based on derived transfer function of shoot-through duty cycle-to-Z-network capacitor voltage and simplified modulation strategy, the modulation strategy of Z-network capacitor voltage has been described in detail, which simplified the controller design and improved the transient response. The simulation and experimental results verified the validity of proposed control strategy.

Key words: Z-source inverter; PID controller strategy; boost-buck

CHEN Ming, SUN Xu-dong, HUANG Li-pei

 (State Key Lab of Control and Simulation of Power System and Generation Equipments,

Dept. of Elec. Eng., Tsinghua University, Beijing 100084, China)

DONG Bo, LI Yong-dong, ZHENG Zhi-xue

(Department of Electrical Engineering, Tsinghua University, Beijing 100084, China)

Abstract: This paper focuses on energy management of hybrid storage system which consists of batteries and super-capacitor in a distributed renewable generation system including a wind turbine (2KW), photovoltaic panels (1KW), batteries (one cell is 12V, 65AH and six cells are series connected) and super-capacitor (72V, 70F). According to state of charge (SOC) of battery and super-capacitor, there are several modes in storage system. Control strategy for each mode is described in both grid-connected and islanded operations based on characters of battery as a long-time storage and super-capacitor as a fast-dynamic storage. With the control strategies power can be kept balanced in distributed renewable generation system in order to reduce fluctuation of wind and solar to utility grid and work in islanded operation. Simulation and experimental results are shown to verify the control strategies.

Key words: battery; super-capacitor; distributed renewable energy generation; energy management

LI Qing-quan, FANG Xin-zhen, XU Guang-ke, HU Peng-fei, ZHANG Yuan-tao

(School of Electrical Engineering，Shandong University，Jinan 250061，China)

LIU Qing, WANG Tai-yong, DONG Jing-chuan, LIU Qing-jian, Li Bo

(School of Mechanical Engineering, Tianjin University, Tianji 300072, China)

Abstract：This paper proposed a method of estimating the stator flux and the rotor speed based on extended state observer (ESO) for permanent magnet synchronous motor (PMSM). In this method, the stator flux is chosen as state variables, and the uncertain components including the rotor speed are extended into a new state variable. Then the stator flux and speed can be obtained by ESO timely. Simulation and experimental results show that the new control strategies improve the system dynamic, static performance and robustness significantly.

Key words: PMSM; ESO; sensor-less; direct torque control

 LI Li-bo¹，YAO Chen-guo²，CHEN Pan^2,3, LI Cheng-xiang ²

(1. Qinan Power Supply Bureau of Chongqing Electric Power Corp., Chongqing 401420, China; 2. State Key Laboratory of Power Transmission Equipment and System Safety and New Technology Chongqing University, Chongqing 400044, China; 3. Jiangbei Power Supply Bureau of Chongqing Electric Power Corp., Chongqing 401147, China)

Abstract: This paper used a hybrid technique combining the charge simulation (CSM) and boundary element method (BEM) to calculate the electric field. In this method, the influence of circuit breaker, insulating switch, tower and other elements in the substation is taken into account. In order to shorten computing time, this paper used the direct integration approach. The simulation results are basically consistent with the measured results and proved that the method can be used to forecast the power frequency electric field distribution in the substation.

Key words: substation; charge simulation; boundary element method; power frequency electric field; simulation

Abstract: The 500kV and above transformer substation systems always select the 3/2 connection mode，and this mode has its own characteristics at the structure of main connection and the disposition of protection．Firstly, this paper establishes the initial decision table of fault diagnosis after analyzing trip strategies of protection about the 3/2 connection system．Then the paper proposes a fault diagnosis method based on rough set and Petri nets．This method has three parts：to calculate the reduced attribute setby the rough set theory; to construct the Petri net model based on the rules from the reduced attribute set; and to diagnose the fault through parallel reasoning of Petri nets．Finally, the paper gives some tests of the fault diagnosis．The results show that this method can diagnose the fault localization of 3/2 connection mode accurately and it is good at the diagnosis speed and the fault tolerance．

Key words：rough sets; Petri net; 3/2 connection mode; fault diagnosis

ZHOU Ji-an¹, JIN Dan¹, WANG Wei-zhou¹, DAN Yang-qing², LIU Wen-ying²

(1. Gansu Provincial Electric Power Company, Lanzhou 730050, China; 2. Electrical & Electronic Engineering School of North China Electric Power University, Beijing 102206, China)

Abstract：In view of the problem that huge power supplies grid-connection causing the increase of short-circuit current, different short-circuit current increasing under different huge power supplies grid-connection modes is analyzed according to symmetrical short-circuit current calculation formula. The selection principle of huge power supplies grid-connection modes which can effectively limit short-circuit current is put forward and it can be referred in the actual planning and construction of power grid. The validities of modes that huge power supplies connected to high-voltage bus and nodes with little current contribution coefficient are indicated by the simulation instance.

LI Hai-tao, SHAO Hui, DONG Liang, ZHU Ying-wei, YAN Zhong-ming, WANG Yu

(MOE. Key Lab of Maglev Technology and Vehicle, Southwest Jiaotong University, Chengdu 610031, China)

Abstract: In order to realize the pulse current output of superconducting magnetic energy storage inductor, this paper made a systematical study of a new pulsed power output mode which was based on superconducting energy storage pulse transformer. In this mode, nonlinear resistance was used as discharge resistor. According to the characteristics of nonlinear resistance, this paper made a simulation study of the effects on the system energy conversion produced by the nonlinear voltage and the transformer coupling coefficient. Furthermore, this paper studied the advantages of nonlinear resistance by comparison with the linear resistance. The results show that this pulsed power output mode is feasible. By choosing appropriate nonlinear voltage and improving the pulse transformer coupling coefficient, high pulse current output and high energy conversion efficiency can be obtained under the current technical conditions.

Key words: pulsed power; pulsed transformer; nonlinear resistance; superconducting inductance; magnet energy storage

 

LI San-qun, GUAN Xiao-cun, LI Zhi-yuan, LIU Shu-meng

(Ordnance Engineering College, Shijiazhuang 050003, China)

Abstract：Based on Maxwell equation and electromagnetic field theory, magnetic field control equations with eddy current of solid armature and wound armature are presented in this paper. The equations are solved by finite element method. Based on finite element software ANSOFT Maxwell, the simulative research on axial electromagnetic force, speed and eddy current distribution of solid armature and wound armature are made in ANSOFT. Through comparison of them, it is concluded that the electromagnetic characteristics of wound armature are better than solid armature, which forms the foundation for wound armature fabrication and handling.

Key words：solid armature; wound armature; eddy current; ANSOFT

 

Abstract: This paper includes an illustration of the electrostatic adhesion mechanism which is applied in the particular area of wall climbing robots. The adhesion mechanism of electrostatic adhesion technology will be researched at the beginning, then, the theoretical attraction force model between the electrodes and wall is built. Through the principle of virtual work, the paper obtains a mathematical expression of electrostatic adhesion, and for more complexity, makes a specific investigation of double electrodes type, which is the base of comb-shaped electrodes. Schwarz-Christoffel transform will be utilized in this part, and it is an effective method in dealing with non-uniform electric field. Next, Matlab software is used to analyze the key factors which affect the adsorption strength in the electrodes. To illustrate the problem further, a simulation of voltage between the electrodes is done. Finally, to verify this adhesive function, an experiment with comb-shaped electrodes is done, from which it can be concluded that electrostatic adhesion can be a large attraction power in wall-climbing robots application.

 

PENG Bo¹, REN Xiao-yong², CHEN Qian-hong²

(1. Beijing Institute of Control Engineering, Beijing 100080, China;

2. Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China)

Abstract: The gyrator-capacitor model is one of the preferable models for magnetic components. The representation of the transformer’s leakage inductance in gyrator-capacitor model based on the principle of energy equality is given in this paper. The calculation methods of the equivalent leakage permeance capacitor of different types of transformers are presented in the paper. Besides, the calculation method of the permeance capacitor of interleaved windings transformer is also presented in this paper. The experimental results verify the validity of the proposed method.

Key words: gyrator-capacitor; leakage inductance; leakage permeance capacitor; flat transformer; interleaved windings

 

Abstract: With the development of micro electro mechanical systems and robotics, microrobot became a hot issue. Bacteria flagellar motors as microactuators for untethered microrobots, effectively overcome the shortage of the wire and the battery, so bacterial microrobots become an important branch in the area of microrobotics. Firstly, the research background and the research advance of the bacterial microrobots are introduced. Then some correlative technology problems and perspective in future are analyzed. Finally potential applications and development challenges of the bacterial microrobotics are pointed out.

Keywords: bacterial microrobots；flagellum；taxis；magnetic control；location tracking

 

LIU Jue-min¹，FU Yi¹，LU Wen-jun¹，LI Ya-ping²

(1. Hunan University, Changsha 410082, China; 2. National Center for Quality Supervision and Testing of Relay and Automation Equipment, Xuchang 461000, China)

Abstract：A method using high-frequency pulse train to replace the wide triggering pulse by using impulse analysis theory is proposed in the paper. Firstly, a mathematical model of excitation circuit and thyristor triggering circuit is established, and the expressions for calculating the thyristor triggering pulse width and the pulse period and pulse width of high frequency pulse train based on the thyristor conducting time, latching current, and parameters of excitation and triggering circuits with the inductive load are deducted. The program of high frequency pulse train for the microcomputer controlled excitation system based on the calculated results is used in LM-01 system and a dynamic simulation test is carried out. The test waveform and data indicate that the proposed method gives good symmetry, stability and high precision, and the excitation voltage is continuously adjustable, achieving the requirements for the three phase controlled thyristor rectifier bridge "double-narrow pulse triggering" at inductive load. It proves that the analysis method and the calculations are correct and feasible.

Key words：high-frequency pulse train；theorem of impulse；pulse transformer；double narrow pulse trigger；inductive load

GAO Yuan¹, CHANG Hong¹, WANG Jun-feng², LIU Gao-yuan², ZHANG Bin², CHEN De³

(1.School of Elec. Eng., Xi’an Jiaotong University, Xi’an 710049, China; 2.Xi’an Xirui Protection and Control Co Ltd, Xi’an 710077, China; 3.Xi’an University of Posts and Telecommunications, Xi’an 710061, China)

Abstract: Based on working over the configuration theories of the standard IEC 61850 “Communication Networks and Systems in Substations”, this paper analyses systematically the functional requirements and the thinking of IED configuration tool, and then explains its system frame, XML parser and the concrete implementation method of the composition modules which consist of the parts of main program, documents and data processing as well as the module of calibration and download in detail.

Key words: IEC61850; SCL; IED configuration tool

(School of Electrical and Information, Sichuan University, Chengdu 610065, China)

Abstract: A method to identify a fault section in distribution network by voltage sags pattern recognition is proposed. The method established an analytical voltage sags database using fault analysis. When a real short circuit fault occurs, the voltage at the monitored node is compared with the analytical voltage sags in the database to find all the possible fault sections. Then, the method applied rank reasoning analysis to prioritize all the possible fault sections, and check the possible fault section according to the rank. Through simulating a 11kV typical test distribution network, it proves the proposed method’s validity and accuracy.

Key words: faulted section; voltage sags; voltage sag pattern characteristic; pattern recognition; distribution network

Abstract: Expert system and visualization technology are both used in grid maintenance scheduling. The normative maintenance data, from grid maintenance database, is inherited from the grid structural knowledge of EMS system. At the same time the knowledge-base can be constructed on the basis of constraint requirement which is closely related to maintenance，forming maintenance scheduling arrangement expert system. In addition, according to the active rule model, the maintenance data can be analyzed and adjusted, with “changing color” or “flashing” ways for alarm. Finally, a scientific and practical grid maintenance scheduling is compiled automatically. The proposed method is proved to be valid and practical by the monthly maintenance scheduling of Lanzhou power grid.