Quantum-behaved particle swarm optimization algorithm for economic load dispatch of power system
ZHANG Zhi-sheng1,  LIN Tao2,  WANG Kun1,  SUN Ya-ming3
(1. School of Automation Eng., Qingdao University, Qingdao 266071, China; 2. Qingdao Elec. Power Company, Qingdao 266002, China; 3. School of Elec. & Automation Eng., Tianjin University, Tianjin 300072, China)
Abstract: Quantum-behaved particle swarm optimization algorithm is firstly used in economic load dispatch of power system in this paper. The algorithm is based on convergence behavior of particles in particle swarm, which is presented according to quantum physics theory. It changes evolutionary search strategy of traditional particle swarm optimization algorithm. Particles can search global optimal solution in whole feasible solution. The evolution equation of new algorithm need no velocity vector, and the form of equation is simple, which parameters is less and is easier to control. The algorithm is simulated by two cases, which validates that it can effectively solve the problem of economic load dispatch. Through performance comparison, it is obvious that the solution is superior to that of improved particle swarm optimization algorithm and other optimization algorithm. This paper lays necessary theoretical foundation for practicality for economic load dispatch of power system based on quantum-behaved particle swarm optimization algorithm.
Key words: power system; economic load dispatch; quantum-behaved particle swarm optimization; value-point effects

A combined algorithm for reactive power optimization of distribution network
DANG Ke1，WANG Dan-hua1，DANG Tong2
(1.Northeast Dianli University, Jilin 132012, China; 2.Chengdu Waste-to-Energy Co., LTD, Chengdu 610108, China)
Abstract: The simple genetic algorithm is constrained by its poor converging performance and readily leads to local optimization. So in this paper, a combined GA, which can retain the advantages of GA, simulated annealing (SA) and tabu search (TS), is introduced. At first, according to the value of individual fitness the adaptive crossover and adaptive mutation are performed, and heuristic border upon mutation can speed up the anagenesis. Thus the diversity of group is increased and the local optimum can be avoided by simulated annealing. Then the tabu search with a specifical probability is used to improve the local search capacity. To improve the computation speed and accuracy, decimal integer encoding and reserving the elitist are adopted. One real system is used to test the performance of the combined genetic algorithm. Test results show that the hybrid genetic algorithm possesses following advantages: good computation speed and global convergence and high calculation accuracy.
Key words: distribution network; power system; local mutation; combined algorithms

Research on constant current source for LED based on sliding mode control
FENG Bo, ZHAO Zheng-ming, ZHANG Ying-chao, YUAN Li-qiang, ZHOU De-jia
(State Key Lab of Power Systems, Dept. of Elec. Eng., Tsinghua University, Beijing 100084, China)
Abstract: Light-Emitting Diode (LED) has been widely investigated in lighting systems for its advantages of high luminous efficiency, long lifetime and so on. However, it is difficult to control LED with high performances due to its characteristics of nonlinearity and temperature sensitivity. A novel method of sliding mode control (SMC) for LED lighting system based on boost converter with constant current source is proposed in this paper. A new sliding surface is established, which eliminates the complicated model of nonlinear load. Simulations have been conducted using PSIM software; and based on that, a 50W photovoltaic LED lighting system has been developed to implement a serial of comparative experiments. The results show that the designed system with SMC exhibits several advantages, such as simple algorithm, excellent robust and dynamic performances.
Key words: light-emitting diode (LED); Boost converter; sliding mode control; dynamic response

A novel method to seek quickly the superior PI parameters in prime mover simulation system
TAN Li-xin1,2, LIU Jue-min1, CHEN Ming-zhao1, LIU Yan-zhe1, SON Xiao-ming1
(1. College of Electrical and Information Engineering, Hunan University, Changsha 410082, China;
2. Dept. of Information Engineer, Hunan College of Information, Changsha 410200, China)
Abstract: This paper proposes a method to use the genetic algorithms to optimize the PI regulator parameter in the prime mover simulation system. In this paper, we compared the step response characteristics under the conditions of the genetic algorithms and traditional method by MATLAB simulation and by field test, and tested the dynamic characteristics of the prime mover simulation system. The results proved that genetic algorithms can optimize PI parameters quickly. With this method the prime mover simulation system can meet the requirements of dynamic performance simulation.
Key words: prime mover simulation；PI regulate；genetic algorithms；MATLAB simulation；dynamic characteristic

A scheme of reducing common mode EMI based on push-pull compensating circuit
 ZHANG Yong-gao1, GAO Yan-li1, ZHANG Kai2
(1. School of Elec. & Electronics Eng., East China Jiaotong University, Nanchang 330013, China;
2. School of Elec. & Electronics Eng., Huazhong University of Sci. & Tech., Wuhan 430074, China)
Abstract: With the application of high-speed high-power switch devices, severe electromagnetic interference (EMI) is produced due to high dv/dt and high di/dt caused by high speed switching of power devices. An active common mode EMI suppression technique with an external compensating circuit is studied. Two different compensating circuits where the DC biased voltage source is provided by DC bus voltage of converter or external electric supply, which are named as direct and indirect parallel compensating circuit, are introduced. The common mode equivalent model of single-phase half-bridge converter with two kinds of compensating circuit is studied. The calculating process of output capacitor and coupling capacitor in active compensating circuit is illustrated by using the common mode current equivalent mode based on noise source in parellel. And two facts of influence the suppression effect, which are compensating circuit output capacitor and driving resistance are analysised. Experiments validate that the compensating circuit can output the compensating current with equal-large anti-phase of the common mode current produced by converter.
Key words: common mode EMI; equivalent mode; single-phase half-bridge converter; compensating circuit

Fault diagnosis of power electronic circuit based on hidden Markov model
YAN Ren-wu, CAI Jin-ding
(School of Elec. Eng. and Automation, Fuzhou University, Fuzhou 350108, China)
Abstract: Based on discrete hidden Markov model, a new on-line fault diagnosis method for power electronic circuit is put forward. The fundamental theory and algorithms of HMM are presented in the paper in allusion to fault diagnosis of power electronic circuit. The process of recognition based on HMM is divided into two stages: the training stage and the recognition stage. A three-phase SCR rectifier circuit with inductive load is used as an example to illustrate the new approach of fault diagnosis. The method, which is verified by both simulation and experiment can diagnose faults of three-phase rectifier effectively and can also be used for reference in other application in engineering and practice.
Key words: fault diagnosis; power electronic circuit; hidden Markov model

Study on mathematical physics model of DC PD repetition rate
SI Wen-rong, LI Jun-hao, Guo Hong, GU Le, LI Yan-ming
(School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
Abstract: The mathematical physics model of DC PD repetition rate are described in this paper in order to investigate the influence of the measuring circuit on the DC PD repetition rate, based on ABC resistor-capacitor equivalent circuit and AB capacitor equivalent circuit, respectively. Both of them indicate that the relationship of DC PD repetition rate and test DC voltage can be treated linearly approximately if the test voltage is higher than the PD inception voltage. The model deduced from the AB capacitor equivalent circuit also shows that the measuring circuit can only influence the discharge repletion rate temporarily. On reaching the stationary state, the DC PDs are governed by the electric qualities of the dielectric used. The analysis result of PD measurement with wide-band detection technique of three basic oil-paper insulation defect models under DC voltage are shown, which proves the validity of the mathematical physics model.
Key words: DC; PD; repetition rate; mathematical physics model; wide-band detection; oil-paper insulation

Study on Electrical electrical Tree tree in PMMA under Repetitive repetitive Nanosecond nanosecond Pulses pulses
REN Hao1,2,  WANG Jue1, YAN Ping1
(1. Institute of Electrical Engineering Chinese Academy of Science，2. Graduate School of Chinese Academy of Science，Beijing, 100080, China)
Abstract: In this paper, the phenomenon, influence factor and research status of electrical tree in polymer have been introduced. The experimental tests of the electrical tree aging in PMMA under repetitive (～300Hz) nanosecond pulses (70ns) are carried out in our lab. The negative high voltage pulses are applied on samples. The experimental results are shown that the higher voltage, the higher growth speed of electrical tree in PMMA. With the frequency increased, the initial growth speed of electrical tree is increased. The stagnant period is existed in growth of electrical tree. The probability of jungle tree appeared will be increased with the frequency increased. The crack is appeared in needle electrode adjacent under high frequency high pulses, and then the tree is followed.
Key worlds: nanosecond pulse; repetive frequency; PMMA; electrical tree

A new compensation method for current reference of active power filters
LI Xue-nan, SHEN Chen, CHENG Jian-zhou, MEI Sheng-wei
(State Key Lab of Power Systems, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract: As a dynamic harmonic filtering equipment, the active power filter (APF) is required to have a very fast response to the compensated signal. However, the process of data collection, arithmetic calculation and PWM bring time delay more or less. Obviously, the time delay has a negative impact to the overall performance of an APF. To alleviate the influence of time delay in APF, this paper sets up a transfer function for the APF control system, in which time delays introduced by different processes are considered. The frequency response of the transfer function is analyzed in MATLAB. The fact that both the magnitude and phase of the current reference are distorted is revealed. Besides, it is observed that the system voltage at the link point has significant influence to the current reference. Based on the analysis, a new method to compensate the time delay of APF control system is proposed, which modifies both the phase and magnitude of the current reference while it also takes into account the influence of system voltage. Experiment results validate the necessity of the modification and demonstrate the effectiveness and efficiency of the proposed method.
Key words: active power filter; control delay; delay compensation; transfer function

Research on CRC’s calculating method and realization in converter communication
HU Si-deng, ZHAO Zheng-ming，ZHANG Yong-chang
(Dept. of Electrical Engineering, The State Key Lab of Power System, Tsinghua University, Beijing 100084, China)
Abstract: In order to solve the problems of the communication discontinuity and high data error in the converter application especially in serious electromagnetic environments, and also to guarantee the efficient, timely and reliable transmission in the communication system, this paper introduced the cyclic redundancy check (CRC) in ModBus Protocol, analyzed the rule of error check, proposed the method in software realization and parameter selection. A flow for the design in CRC algorithm and the implement in the converter communication are also presented. 
Key words: cyclic redundancy check (CRC); algorithm; error check

Energy efficiency of synthesis of H2O2 by H2/O2 plasma
ZHAO Jian-li, ZHOU Jun-cheng, SU Ji, WANG Xiang-sheng, GONG Wei-min, GUO Hong-chen
(Department of Catalytic Chemistry and Engineering & State Key Laboratory of Fine Chemicals
Dalian University of Technology, Dalian 116012, China)
Abstract: To improve the energy efficiency of the direct synthesis of H2O2 from H2 and O2 by non-equilibrium plasma, the influences of discharge gap, discharge frequency and input power on the reactor energy efficiency and the energy transfer efficiency of the power supply were investigated. The increase of the discharge frequency and the input power, and the reduction of the discharge gap of the reactor can improve the reactor energy efficiency, but will lead to the decline of the energy transfer efficiency of the power supply. The reactor energy efficiency reached 150 gH2O2/kWh in this study. Nevertheless, due to the relatively low energy transfer efficiency of the power supply, the total energy efficiency of H2O2 synthesis was less than 9 gH2O2/kWh. So to improve the total energy efficiency for the direct synthesis of H2O2 by non-equilibrium plasma, the design of highly efficient DBD reactor and the development of matchable power supply for the reactor are both necessary, and the latter is more important. 
Key words: hydrogen peroxide, plasma, energy efficiency, energy efficiency of reactor, energy transfer efficiency

Research on realizing of fast opening of short-circuit faults for low voltage system
　　　  ZHENG Xin1，ZHANG Pei-ming1，CHEN Li-an2
(1. College of Electrical Engineering and Automation, Fuzhou University, Fuzhou 350002, China；
2. Dept. of Electronic Engineering, Xiamen University of Technology, Xiamen 361005, China）
Abstract: This paper analyses the main problems for the early detection of short circuit fault, and a fast-opening control system for short-circuit is designed and validated based on the early detection model. The issue about the real application of early detection for short circuit fault is solved and this paper provides an effective method to develop an intelligent protective apparatuse.
Key words: short-circuit fault; morphological wavelet; early detection; fast opening control

Research and application of novel DC/AC inverter topology
JIANG Xiao-mei, RUI Yan-nian
(College of Mechanical and Electronic Engineering, Soochow University, Suzhou 215021, China)
Abstract: A novel DC/AC inverter circuit topology and its operation principle have been proposed. It is a voltage-fed quasi-resonant soft-switching series–parallel inverter that can attain soft-switching operation and regulate its output power continuously over a wide range. The inverter is joined with a boost power-factor correction converter at the input line to make the line current follow naturally the sinusoidal line voltage. Using reverse recovery attribute decreases energy consumption of this new circuit. Additionally, the new inverter can achieve wide range and smoother output power regulation accordingly smoother input power regulation and lower power consuming than the conventional inverter, widening the regulation range as well as high conversion efficiency is attained under soft-switching operation. Despite more electronic components and complex circuit, with the rapid decline of price of semiconductors and ferrite core, electronic ballast production cost has decreased significantly. High performance can bring about economic benefits and great market potential.
Key words: quasi-resonant series–parallel; soft-switching; DC/AC inverter

A bi-directional DC/DC converter with opposed-polarity transformer
ZHANG Tao, QU Wen-long
(State Key Lab of Power Systems, Dept. of Elec. Eng., Tsinghua University, Beijing 100084, China)
Abstract: A bi-directional DC/DC converter with the opposed-polarity connection of isolated transformer is proposed. The second winding has two connecting forms of same polarity and opposed-polarity. The operational principle and features are described. The power transferred is deduced, and the relations with the duty cycle, phase angle shifted and source voltages are investigated. The voltage stress and current stress between the two forms are compared. Under the condition of 50% duty cycle and power control by shifting phase angle, these two polarity connections have same capacity of power output. The experimental results show that the converter with opposed-polarity connection.can also work normally by adjusting duty cycle.
Key words: bi-directional DC/DC converter; transformer opposed-polarity connection; power transfer; phase shifting control; duty cycle control

Serial-charge-parallel-discharge inductive energy supply for coilgun system
ZHAO Liang-ying, LIU Xiu-cheng, YU Xin-jie
(State Key Lab of Power System, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China)
Abstract: A model of the serial-charge-parallel-discharge inductive energy supply for the single stage pulsed inductive coilgun system was set up in this paper. The performance of the system was simulated with PSpice. The influences of the time constant of the projectile coil, the transfer capacitor, and the initial displacement of the projectile coil to the launch process were analyzed using the simulation platform and some important conclusions for the coilgun design were obtained based on the above analysis. In addition, some key parameters in the launch process were compared between the topology with one energy storage coil and the topology with two serial-charge-parallel-discharge energy storage coils. An experiment was carried out based on the laboratory-level system, which contained two serial-charge-parallel-discharge energy storage coils. The experimental results coincided with the simulations, which verified the correctness of the equivalent model. In the experiment, the control system was designed based on the DSP TMS320F2812. The simulations, the analyses and the experiment provided instructive data and experience for the future research on both the coilgun system design and the serial-charge-parallel-discharge inductive energy supply.
Key words: inductive energy supply; coilgun; pulsed power supply; PSpice; DSP

Research of data exchange between AEMS and EMS
XU Peng-liang1, HE Guang-yu1, MEI Sheng-wei1, WANG Wei2, ZHANG Wang-jun2
(1. State Key Lab of Power Systems, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China;
2. Shanghai Power Grid Co., Shanghai 200122, China)
Abstract: Based on practice in power system, a solution of the problem of data exchange between AEMS and EMS is given. AEMS is a distributed application system based on SOA (Service-Oriented Architecture). To realize this, we designed a data exchange platform composed of server and clients. This platform is used to solve the data exchange problem between AEM and EMS，and provide data exchange service. The data exchange between AEMS and EMS, the design and the realization of the data platform, the difficulty of data exchange and the running effect were expatiated. The system has been running steadily in shanghai power grid since 2007 April and shows excellent performance.
Key words: advanced EMS; data exchange platform; hot standby

Experimental study of pseudospark-switch with ferroelectric trigger
DING En-yan1,2, LI Ai-ping1, FAN Zhi-kai1, JIN Xiao1, YANG Zhou-bing1, GAO Feng-qin1 
（1. Institute of Applied Electronics, CAEP, P.O.Box919-1015, Mianyang 621900, China;
2. Postgraduate Department, CAEP, Beijing100088, China）
Abstract: As the key part of the pulse power technology, at the present time the development of high voltage switch is using the technology of high repetition and low jitter. In this paper, the work principle of the ferroelectric switch and its experiment results were introduced. The relation among the pressure, rising time and delay time is found through the experiment and the paper analyses the reason that causes the relation among the pressure, rising time and delay time. The jitter of the switch was less then 3ns when the gap between the anode and cathode is 3mm, the vacuum is 2.5 Pa, the height of the hollow cathode is 19mm, the diameter of the pore is 4mm and the trigger voltage is 3.55kV in the experiment. The value of the trigger voltage has important affect on the jitter of the switch, as the jitter of the switch is reduced with the increase of the trigger voltage. The jitter of the switch was less than 1ns when the trigger voltage is about 6kV.
Key word: pseudospark switch; hollow cathode; ferroelectric trigger electrode

Researching and developing of synthetic criterion selection protection system based on MSP430
WANG Qi, YUAN Zhen-hai
（Nanjing University of Technology, Nanjing 210009, China）
Abstract: In this paper, based on the analyzing of zero sequence transient energy, zero sequence active power, zero sequence DC current creepage protection system principle, and further studying of the selective leakage protection principle of zero sequence DC current, an improved schemes for the selective leakage protection principle of zero sequence DC current is proposed, and a creepage synthetic protection scheme which combined these three principles is presented. Also a creepage synthetical line selection protection equipment and its software were designed. Finally, it can achieve the goal to monitor the insulation resistance of power network, and to improve the accuracy of selecting faulted line. Blocking method was adopted in designing of the system hardware, which consists of data acquisition unit, processing unit and so on. Software synchronous sampling of multi-route alternating current signals was realized by software settings. Blocking method employing FFT was also adopted in designing of the system software, which includes system initializing, software of line selective principle, interface of LCD, and the high level computer communication and so on.
Key words: power network; earth leakage protection; arc-suppression and ground faulted line detection; MSP430F449