A proposal for planning and constructing a national integrated energy base combined with large-scale photo-voltaic power and hydropower in Qinghai province
YAN Lu-guang, ZHOU Xiao-xin, ZHANG Chu-han, FEI Wei-yang, XIA Xun-cheng, ZHOU Feng-qi, HU Xue-hao, XU Hong-hua, HUANG Chang-gang, LIU Feng-song, WANG Shu, MA Ji-ming, WANG Bao-guo, PENG Yan-chang
(Academic Divisions of Chinese Academy of Sciences, Beijing 100864, China)
Abstract: Academic Divisions of the Chinese Academy of Sciences have organized relative academicians and experts to accomplish a study about synthesized energy base combining large scale photo-voltaic power generation and hydro-power in Qinghai province. In this paper the significance of synthesized energy base combining large scale PV power generation and hydro-power were discussed. The existing groundwork and special meaning of planning and constructing synthesized energy base in Qinghai province were indicated. The facing problems and measures which have to be taken into action were pointed out also.
Key words: Qinghai province; photo-voltaic power generation; hydro-power; national synthesized energy base

synchronous transmission of power and signal 
SUN Yue，WANG Chen-chen，TANG Chun-sen，DAI Xin, WANG Zhi-hui
(Dept. of Automation, Chongqing University, Chongqing 400030, China)
Abstract: According to the signal transmission’s problem in inductive coupled power transfer system, a novel digital signal transmission method based on energy channel is proposed in this thesis. This method is to change the resonant converter soft-switching period to modulate its digital signals, while the electrical energy sink was received through power regulation unit, extracting the characteristic of modulation signal and performing signal restoring. This method will transfer digital signals in the condition of keeping the inductive coupled power transfer system unchanged. This thesis analyzes a fundamental principle of signal transmission method. The experiment verified that this kind of signal transmission has many advantages on its reliability and it has wide applications in the ICPT system. 4 Refs. In Chinese.
Key words: inductively coupled power transfer; power modulation; soft-switching
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 10—13.

A novel power flow analysis for distribution system considering voltage regulation and distributed generation
LIU Qing-zhen, CAI Jin-ding
(Electrical Engineering &Automation College, Fuzhou University, Fuzhou 350002, China)
Abstract: The paper proposes a promising power flow analysis method for radial distribution system with distributed generations (DGs) combined with voltage regulating facilities. In the paper, the multiple node styles of different DG units are analyzed and a suitable model of SVR in power flow analysis is determined. It also studies the influence of DG on voltage regulating equipments. Backward/ Forward Sweep method is improved, so it can effectively deal with multi-style node and can update the ratio of SVR during the power flow iteration. Then an example of 28-node radial distribution system with DGs is performed to validate the method proposed in this paper. At the same time, the simulation results show that DGs effect the voltage profile, power losses and voltage regulator operating status greatly. 12 Refs. In Chinese.
Key words: power flow analysi; radial distribution system; distributed generations; voltage regulating
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 14—17.

Impedance characteristics of LC unit for plane integrated filter
ZHOU Xiao-lin，WANG Shi-shan，CUI Yong-sheng
(Nanjing University of Aeronautics and Astronautic，Nanjing 210016，China)
Abstract: The integrated LC structure, achieving the integration of inductance and capacitance with the layer capacitance of inductance winding, is the basic unit constituting the planar integrated EMI filter. In order to estimate the high-frequency characteristics of EMI filter, it is essential to build the high-frequency model of the integrated LC structure. Distribution of electric and magnetic fields of transmission line, connected in differential modes, is discussed, and its equivalent circuit is analyzed. Based on the generalized transmission line theory, high-frequency model of integrated LC coil is built. The LC coil is equivalent to a two-port network, and impedance matrix is derived using model transformation matrices. The electrical parameters of per unit length are calculated. The integrated LC coil is connected in series and parallel resonant structure, and the impedances of the integrated LC structure with different connections are measured, and the accuracy of the model is verified by measured impedances compared with the calculated one. 6 Refs. In Chinese.
Key words: planar integrated magnetics；integrated LC unit；high-frequency model
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 18—22.

Study on coupling organization of non-contact power transmission
LIU Yi, WEN Bo, NIE Yi-xiong
(Faculty of Automation, Guangdong University of Technology, Guangzhou 510090, China)
Abstract: There are a number of problems associated with non-contact Power Transfer techniques when applied to long distance field. Coupling efficiency is a priority issue in the design. In this paper, a new type of multi-coil parabolic emitting structure, which is used for non-contact power transmission, was simulated by using ANSYS software. And the comparative study between multi-coil planar structure and parabolic one are carried out also.  The simulation results proved this kind of structure has better coupling characteristics. By the analysis to the calculation results of the mutual inductance and the coupling-coefficient of parabolic coupling structure in different emitting-receiving distance, it is discovered that the change of frequency have some influence, and the reasons are analyzed from the Kelvin-effect theoretically then. Finally, the infection of the change of self-inductance and mutual-inductance with the power frequency to the reactive power compensative capacitor and the problem of receipt side compensative circuitry design are discussed.
Key words: coupling organization, coupling coefficient, frequency, compensated circuit

Research on discharge of superconducting magnet to inductive load
LI Hai-tao, ZHU Ying-wei, SHAO Hui, YAN Zhong-ming, DONG Liang, HU Ji-shi, WANG Yu
(MOE.Key Lab of Maglev Technology and Vehicle, Southwest Jiaotong University, Chengdu 610031, China)
Abstract: In the high-power pulse source based on superconducting inductive energy storage system, the over-voltage from superconducting magnet is always existed when the magnet discharges to the inductive load. The over-voltage would seriously threat the security of superconducting magnets. This paper presents the theoretical analysis of the methods of over-voltage suppression, and the transient discharging process is researched by the simulated analysis and arithmetic comparison. The characteristics of over-voltage suppression of three switching circuits were analyzed. The results show that these three kinds of switching circuits can achieve the purpose of magnet’s over-voltage suppression, while the performance of switching circuit with the nonlinear resistance is superior to that of the linear and is suitable for the load with quick ratio pulse current requirement. The capacitive switching-circuit is suitable for the low power loss situation. 11 Refs. In Chinese.
Key words: power pulse, superconducting magnet, inductive load, over voltage, nonlinear resistance, capacitor
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 27—30.

A novel soft-switching three-level inverter with self DC voltage balance capability
LOK Io-Keong, DAI Ning-yi, WONG Man-Chung
(Faculty of Science and Technology University of Macau, Macau, China)
Abstract: This paper presents a combination of a quasi-resonant dc-link (QRDCL) inverter and a generalized three-level inverter. QRDCL inverter can provide a zero voltage condition for the power devices. The voltage stresses of the power devices and the switching losses of the inverter can be reduced. Generalized multilevel inverter topology provides an alternative way in high level inverter implementation. The generalized multilevel topology gives the inverter a self voltage balancing ability without any assistance from extra circuits. Control strategy of a generalized three-level QRDCL inverter is proposed. Simulation results of the inverter are also presented to prove the feasibility of a generalized three-level QRDCL inverter. 9 Refs. In Chinese.
Key words: Quasi-Resonant DC Link (QRDCL); soft-switching; multilevel inverter
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 31—34.

Research on parameters identification for dielectric response equivalent circuit of transformers with oil-paper insulation
ZHANG Tao, CAI Jin-ding
(College of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350108, China)
Abstract: Return voltage measurement (RVM) based on dielectric response testing techniques is being investigated as potential tools for condition assessment of transformer insulation. It is a simple, fast and nondestructive method to monitor insulation status of transformer and estimate the moisture content of paper insulation. The initial slope of return voltage has close relation with thermal aging of transformer. It is an important characteristic parameter to assess insulation aging and is also of great significance to identify the parameters of dielectric response equivalent circuit. This paper establishes a mathematical model with the data of initial slope of return voltage for solving parameter of dielectric response equivalent circuit, which is a group of nonlinear equations with exponential function. The problem to be solved for nonlinear equations is transformed to the constrained optimization problem using nonlinear least square method, and then the particle swarm optimization algorithm is used for solving the problem. The result shows that the established model is feasible and effective. It provides a new idea for assessment of insulation aging and research on new characteristic parameters. 10 Refs. In Chinese. 
Key words: return voltage; initial slope; parameters identification; dielectric response; insulation paper; transformer
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 35—39.

Solenoid coil optimization of electromagnetic brake based on improved genetic algorithm
LU Zhi-gang, SUN Song-qiang
(Key Lab of Power Electronics for Energy Conservation and Motor Drive of Hebei Province,
Yanshan University, Qinhuangdao 066004, China)
Abstract: Based on the Standard Genetic Algorithm (SGA), search space contract method using stability margin is given in this paper, which can enhance the efficiency and precision of the basic method. The concept of individual crowding-distance that keeps diversity and dispersion of populations before the space contract is introduced, and the method guarantees the optimal result existing in the strong solution space. Then, we do some research on the geometrical structure and attraction force of electromagnetic system, give the mathematics optimization models of solenoid coil, and carry out optimization on the parameters with the Improved Genetic Algorithm (IGA). The simulation result shows that IGA is valid and feasible, the temperature rise reduces visibly after optimization using our IGA, and the performance of electromagnetic brake is improved. Compared with the optimal results with SGA, it is clear that IGA has the advantages of more precise and more rapid convergence for the optimal problem. 16 Refs. In Chinese.
Key words: solenoid coil; parameters optimization; genetic algorithm; crowding-distance; stability margin; contracting space
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 40—43.

Method to efficiently measure grounding resistances
LU Zhong-shan, ZHANG Xiao-qing, LI Jian-xiu
(School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China)
Abstract: This paper proposes a method to efficiently measure the grounding resistances. In this method the potential electrode can be installed in a circular trace. From theoretical analysis the circular trace equation is derived. The location of the measurement electrodes in this method is very flexible and the layout of measuring wire is very convenient. The restriction of 0.618 and triangle methods on measurement site can be removed by the proposed method.
Key words: grounding resistance; measurement electrodes; earthing system; soil resistivity; grounding resistance measurement

A hybrid strategy based on IPM and PSO for optimal reactive power flow
MA Ji-shan, YANG Hong-geng
(School of Electrical and Information, Sichuan University, Chengdu 610065, China)
Abstract: By integrating a particle swarm optimization algorithm (PSO) with an interior point method (IPM), a hybrid strategy for the optimal reactive power flow (ORPF) problem is proposed. According to the discrete feature of the control variables, the original ORPF problem is decomposed into a continuous optimization sub-problem and a discrete optimization sub-problem, which are solved by IPM and PSO respectively. By solving the two sub-problems alternately，the optimal solution of the ORPF problem can be obtained. IPM and PSO take advantage of each other, so that the efficiency of the hybrid strategy is greatly improved. Based on the particle movement trend and the correlation between network power loss and node voltage, a dynamic adaptive adjusting method for penalty factors and inertia coefficient is presented. Furthermore, the numerical example of IEEE 30-bus system and a local power system is employed to validate correctness and effectiveness of the proposed algorithm. 10 Refs. In Chinese.
Key words: optimal reactive power flow; improved particle swarm optimization(PSO); adaptive penalty factor; interior point method (IPM)
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 48—51.

Practical control strategy analysis on dual-loop soft-startup for active power filter
LUO Qi-feng¹，CHENG Han-xiang²，YU Shu-hai³，ZHANG Yan⁴
（1. Zhongshan Power Supply Bureau of Guangdong Power Grid Corp., Zhongshan 528400, China；
2. Automation College，Guangdong University of Technology, Guangzhou 510006, China；
3. Beihai Power Supply Bureau of Guangxi Power Grid Corp., Beihai 536000, China；
4. Jiangmen Power Supply Bureau of Guangdong Power Grid Corp., Jiangmen 528000, China）
Abstract: The paper is based on the practical problems of the harmonics in distribution network. The key techniques of Active Power Filter have been analyzed in this paper, especially the dual-loop soft-startup control strategy is studied and analyzed to reveal the main control parameters of APF. A 380V 100kVA shunt voltage-type APF experiment prototype using dual-CPU is implemented. Many experiments are done on the experimental equipment of APF and satisfactory result is drawn, which can contribute to actual research development and production. 9 Refs. In Chinese.
Key words: active power filter (APF)；harmonic；compensation strategy；soft-startup control
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 52—56.

Comparative research on single-phase time-sharing photovoltaic inverter
GENG Pan¹, WU Wei-min¹, YE Yin-zhong², LIU Yi-jian¹
(1. The Research Institute of Electronic Automation of Shanghai Maritime University, Shanghai 200135, China;
2. Shanghai Institute of Technology, Shanghai 200235, China)
Abstract: Based on the modeling of two similar time-sharing cascaded photovoltaic inverters, the essential differences of the two circuits caused by different filters are revealed. During the “boost” operating stage, one system is a traditional fourth-order system, while another is a special fourth-order system similar to a second-order system. Consequently, different compensators will be required for these two systems, featuring two pairs of conjugated zeros and an integrator for one system and a simple PID compensator for another. Both the theoretical analysis and the experimental results show that the special fourth-order system could achieve much better control performance as compared with its counterpart. 10 Refs. In Chinese.
Key words: time-sharing; photovoltaic inverter; fourth-order system; PID compensator
 // Adv. Tech. of Elec. Eng. & Energy, 2010, 29(4). 57—61.

RT-LAB based real-time simulation of photovoltaic power generation system
ZHENG He-ling¹, GE Bao-ming¹, BI Da-qiang²
(1. School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China;
2. State Key Lab of Power Systems, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract: This paper presents a single-stage grid-connected photovoltaic (PV) system, using the photovoltaic array simulator instead of the traditional solar photovoltaic cells. The Real-time simulation model based on the RT-LAB software platform has been built. It can neglect the limits of real conditions of the PV experiment in the laboratory. At the same time, it takes the hardware environment into account to fetch up the shortage of all-digital simulation platform. It provides a good simulation platform for the high-power in a real or near real-environment for the laboratory photovoltaic research.
Key words: photovoltaic array simulator; single-stage grid-connected photovoltaic (PV) system; RT-LAB; real-time simulation

Implementation of VSC based controllable interruption generator
YAN Gan-gui¹，QI Lei¹，LI Jun-hui^1,2，WANG Jian^1,2，DAI Wu-chang¹
(1.College of Electrical Engineering, Northeast Dianli University, Jilin 132012, China;
(2.College of Elec. and Electronic Eng., North China Electric Power University, Beijing 102206,China)
Abstract: In order to test the compensation control performance for various power interruption of power quality control equipment all round way, a power interruption generator is developed based on controllable voltage source converter. The main circuit parameters that can fulfill the stability and speed on operation are designed. The design method on DC voltage stability controller based on adjusting the current in synchronous rotating coordinate system is constructed. Experimental results show that the designed method is correct, and the power interruption generator can generate various types of interruption voltage waveforms steadily and flexibly.
Key words: power quality; power interruption; voltage source converter; digital signal processor

Protection analysis of single-phase ground fault at converter transformer valve side
GAO Ai-yun¹, NIE Juan-hong², LI Xiao-hua³, CAI Ze-xiang³
(1.Guangdong Technical College of Water Resources and Electric Engineering, Guangzhou 510635, China; 2. Beijing Sifang Automation Co., Ltd, Beijing 100085, China; 3. Electric Power College of South China University of Technology, Guangzhou 510640, China)
Abstract: Characteristic of single-phase ground fault at converter transformer valve side in HVDC system is analyzed in this article. Protection of converter transformer and converter is discussed. Single-phase ground fault simulation of CIGRE at converter transformer valve is completed by EMTDC. By discussing coordination and strategy of AC/DC protection the fault analysis and protection design in HVDC system are improved.
Key words: converter transformer; single-phase ground fault at valve side; AC/DC protection

Development and applications of pulsed power supply in multi-shot electromagnetic launch
SUN Lian-hua^1,2, SUN Yao-hong², YAN Ping², LIU Chuan-pu^1,2, LI Min-tang^1,2, SUN Cai-xin^1,2
(1. Institute of Electrical Engineering, Chinese Academy of Science, Beijing 100190, China;
2. Graduate University of Chinese Academy of Sciences, Beijing 100049, China)
Abstract: Comparing with routine launch, electromagnetic launch has many advantages such as: high initial velocity, stable performance and good controllability. In the EML system, the pulsed power with high energy storage capacity and quick charging and discharging performance is the basic requirement. In order to meet the needs of the multi-shot experiments and the pulsed impact experiments, a 200 kJ modularize pulsed power was developed. The main work includes the optimal design of the power structure and the PFN, the accurate control of the discharging time sequence and experimental study. The experiment current waves are quite in accordance with the PSpice simulation, and the pulsed power system could be used in the multi-shots of the small mass armatures and the impact test of the armature under high pulse current.
Key words: multi-shots; pulsed power; discharging sequence; pulsed impact experiment