To celebrate the 100th anniversary of higher education on electrical engineering in China — To strive further for development of new technology on electrical engineering
YAN Lu-guang
(Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080, China)
Abstract: The first course on electrical engineering in China was set up at Nanyang College in Shanghai in 1908. This year is the 100th anniversary and it is worth to commemorate it. The paper introduces briefly the prospect, significance and importance of new technology on electrical engineering, its development basis and demand, suggests pay much more attentions to education and training of new technology on electrical engineering for the innovation talents in new generation.　
Key words: higher education on electrical engineering; 100th anniversary; new technology on electrical engineering

Simulation research on inter-turn short circuits of field windings in synchronous machines
SUN Yu-guang, WANG Xiang-heng, GUI Lin, WANG Wei-jian
(Dept. of Electrical Engineering, State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment, Tsinghua University, Beijing 100084, China)
Abstract: When an inter-turn short circuit fault of field winding occurs in a synchronous machine, the field current will increase and the reactive power output will decrease, aggravating the rotor vibration. Severe damage will be caused to the safe operation of the machine if such faults are not handled properly in a timely manner. Existing research follows the experimental detection and qualitative analysis approaches, which are subject to practical limitations due to the fact that the fault current is not able to be calculated accurately. This paper proposes an improved multi-loop mathematical model for calculating the currents of stator and rotor as well as the active power and reactive power for the multi-branch generator with inter-turn short circuit faults of field winding. Quantitatively evaluating the impact of air-gap magnetic field distortion and unbalanced current in phase windings hence becomes possible. Based on the calculation results, the paper gives a summary of the fault characteristics (e.g., the existence of fractional harmonic circulating current and odd harmonic filed current) and their physical meanings, which may serve as the basis for the protection against inter-turn short circuit faults of field windings.
Key words: synchronous machine; inter-turn short circuits of field windings; improved multi-loop mathematical model

Transmission network planning based on artificial fish school algorithm
NIE Hong-zhan, LV Pan, QIAO Yi, YAO Song
 (1. School of Electrical Engineering, Northeast Dianli University, Jilin 132012, China;
2. Guizhou Dafang power generating Co'Ltd, Dafang 551600, China)
Abstract: Artificial fish school algorithm is a kind of optimizing method based on the model of autonomous animals. Every fish changed their position constantly through all kinds of behavior while comparing corresponding food concentration to the optimal one on the bulletin board. After a series of repeated search process, the best result which may be the optimal solution will be finally on the bulletin board. Aiming at the expansion planning of transmission network which is a complex combinatorial optimization problem, a mathematical model was built, and the artificial fish school algorithm was applied to solve the model for the first time. The algorithm has been successfully applied to IEEE Garver-6 system and the 18-bus system, and the results demonstrate the feasibility and efficiency of this method.
Key words: power system; network planning; artificial fish school algorithm

Synthetic grading evaluation of power quality based on incentive mechanism
TAO Shun，XIAO Xiang-ning
（Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control
(North China Electric Power University), Ministry of Education, Beijing 102206, China）
Abstract: In a liberalized electricity market, it is not surprising that different customers need different power quality level with different price. So how to define the synthetic power quality grading evaluation system became a concerned problem. In this paper, five levels (Ⅰ—Ⅴ) of voltage deviations, power-frequency deviations, voltage unbalance, harmonics, voltage flick and distribution reliability considering voltage sags were defined respectively based on the IEC61000-2-4 international standard and power quality actual monitoring results in China. The synthetic power quality level of the monitoring sites was determined by the worst grade of six categories based on cask principle, which is an incentive mechanism. Case study results showed that the proposed method is beneficial to distinguish power quality level and to conduct the quantitative and qualitative evaluation of power quality. The application analysis of the grading evaluation system was also discussed in the paper.
Key words: power quality; quality levels; EMC; synthetic evaluation; cask principle

Fast feature extraction technique for PD pulse shape based on wideband detection

SI Wen-rong, LI Jun-hao, YUAN Peng, LIANG Yong-chun, LI Yan-ming
 (School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
Abstract: According to multi-PDs phenomenon in insulation of high voltage electrical equipments, a novel PD detection and pattern recognition system developed by wide-band technology based on a single pulse shape is proposed in this paper. To develop this system, the fast grouping technique for pulse sequence should be used, which is composed of fast feature extraction technology and clustering analysis method for PD pulse shape. Focus is made on Amplitude-Parameters, Equivalent Time-Frequency and Time-Frequency Entropy methods, which are used to make feature extraction for PD pulse shape-time sequence detected by wide-band technology with a sampling rate of 100Ms/S. After feature extraction made for noised multi-PD data, the results are compared by using fuzzy clustering method. The results show that those methods do a good separation for PD pulses with the same characteristics to a certain extent, respectively. And the analysis result of noised PD date of a gas insulated switch (GIS) shows that the feature extraction methods are effective and feasible for multi-PD pulses sequence grouping in practice. This provides a good method to make feature extraction for pulse shapes to develop the multi-PDs detection and pattern recognition system.
Key words: PD; wide-band detection; pulse shape; feature extraction; on-line monitoring

Slide-mode controlled induction motor servo drive system via double fuzzy-neural network
WANG Rui-ming1, JIANG Jing-ping2
(1. Jiaxing University, Jiaxing 314001, China; 2. College of Elec. Eng., Zhejiang University, Hangzhou 310027, China)
Abstract: Considering the requirement of high performance of induction motor servo drive system，this paper designs such a system with a sliding-mode position controller based on double fuzzy neural network. The effectiveness of the system was analyzed. The analysis and proposed methods were verified by simulation and experimentation. For AC system in practice, it is quite good to resist disturbance and has a strong robustness. The results of simulations and experimentation show that both dynamic and steady performances are improved evidently and the results are satisfactory.
Key words: sliding mode controller；induction motor；servo system；double fuzzy neural network

Development of an AC magnetic field system for hyperthermia
WU Dan1,2, YU Yang1, MA Qiu-feng1,2, ZHAO Wu-yi1,2, HU Li-li1, LV Jing1, PAN Wei-dong1, SONG Tao1
(1. Institute of Electrical Engineering, CAS, Beijing 100080, China; 2. Graduate Univ. of CAS, Beijing 100039, China)
Abstract: We have developed an experimental platform for magnetic nanoparticles hyperthermia and done some heating experiments with the magnetosome. Based on the specific requirement of the experiment, we designed a C-type electromagnet and a series resonant inverter of which the amplitude and the frequency are adjustable. Magnetic field strength of various frequencies and its homogeneity in the gap were measured with a self-made probe. Experiments using the magnetosome extracted from magnetactic bacteria AMB-1 and magnetic fluid were carried out. The results show that the magnetosome has a high specific absorption rate, proving its potential usage in hyperthermia.
Key words: magnetic nanoparticle; target hyperthermia; series resonance; specific absorption rate; magnetosome

A new method for end effect of EMD and its application to harmonic analysis
SU Yu-xiang, LIU Zhi-gang, LI Ke-liang, HUO Bai-chao
(Institute of Electrification & Automation, Southwest Jiaotong University, Chengdu 610031, China)
Abstract: A new method, a combination of support vector regression machines and mirrorizing extension, is proposed in this paper in order to restrain the end effects of Empirical Mode Decomposion (EMD). Firstly, the support vector regression machines are used to predict one maximum and one minimum in each side of the signal. Secondly, EMD method which includes mirrorizing extension procedure is applied in the decomposition of the extended signal. Finally, IMFs (intrinsic mode functions) are obtained with the same length of the original signal. This new method is applied to harmonic analysis, and simulation results show that this method is effective to restrain the end effects of EMD method. Accurate harmonic components are obtain with this method.
Key words: EMD; support vector regression machines; mirrorizing extension; end effect; harmonic analysis.

Study of rail inductance gradient during EM rail launch based on time-frequency analysis
SUN Li-qiang1，YUAN Wei-qun2，YAN Ping2
(1. Graduate Univ. of CAS, Beijing 100039, China; 2. Institute of Elec. Eng., CAS, Beijing 100080, China)
Abstract: A new method that studies the rail inductance gradient during the launch is presented. The working current is processed by the time - frequency toolbox in Matlab, and the curve of time -frequency is obtained. In addition, the rail inductance gradient under different frequency is gained by the simulation in Ansoft. Then by processing the two curves the rail inductance gradient variation with time during launching is obtained. The results show that the current frequency is decreasing during the launch. It is about 1000Hz at the start, while at 2.1ms the armature is about to leave the muzzle, it is only about 100Hz. And the rail inductance gradient is nonlinearly increasing, it rapidly increases to about 0.40μH/m when it is 0.5ms from 0.35μH/m at the start then slowly increases to about 0.41μH/m at 2.1ms when the armature reaches to the muzzle. The force acting on the armature under different gradients, the gradient deriving from the paper and 0.40μH/m, are compared. It shows that at the initial stage the both force are nearly equal, but after 1.0ms they are clearly different, and the latter is smaller about 4％.
Key words: EML; pulse power; rail; inductance gradient; Matlab; time-frequency analysis

Study of phasor measurements based power system harmonic state estimation algorithm
HOU Shi-ying, WANG Yao, ZHU Shi-hou, YAO Zong-pu
 (State Key Laboratory of Safety and New Technology of Power Transmission & Distribution
Equipment and System, Chongqing University, Chongqing 400030, China)
Abstract: With the rapid development of phasor measurement technology, power system harmonic state estimation based on PMU (Phasor Measurement Unit) has its own characteristic that node votage phasors can be chosen as state variables and branch current phasors, node votage phasors and injected current phasors can be selected as measurement variables, and the state equations become linear equations. According to this characteristic this paper combines the different measurement schemes, using Cholesky decomposition algorithm, to solve overdetermined and basic measurement equations, and its computational complexity is just a half of the Gauss elimination method and it is not necessary to select main element which accelerate the computation speed greatly. Singular value decomposition is used to solve underdetermined measurement equations. It offers not only a steady least square solution for power system, but also identifying the observability of power system, which simplifies analytical procedure greatly. At last the simulation and programming indicate the effectiveness and reliability of the two algorithms.
Key words: harmonic state estimation; singular value decomposition; Cholesky decomposition algorithm

Improved double peak of spectral lines algorithm for analysis of power system harmonics
SHENG Zhan-shi, TAN Fei, PAN Tian-hong 
(School of Electrical and Information Engineering, Jiangsu University, Zhenjiang, 212013, China)
Abstract: The traditional window and interpolation is widely employed to estimate power harmonics parameters. Double peak of spectral lines algorithm (DPSLA) could be used to correct the harmonic analysis. And the precision of this algorithm is determined by the precision of the corrected frequency coefficient. Because the fundamental wave frequency can be measured directly by ATT7022B, the double peak of spectral lines algorithm is improved in this paper so the corrected coefficient　 is easy to get and the polynomial approximation method is also employed to obtain simple formulas for amplitude correction. At last, the simulation results and the experiment results have verified the effectiveness and practicability of the new algorithm.
Key words: ATT7022B; FFT; double peak of spectral lines algorithm; Blackman window

Detection and analysis of transient power quality disturbance based on order morphology-dq transformation
LI Yang, HUANG Chun, SHI Jia
(College of Electrical and Information Engineering, Hunan University, Changsha 410082, China)
 
Abstract: The paper proposes a new method to detect transient power quality disturbances based on order morphology and improved d-q transform. Using order morphological transformation in the process of disposing electric signal, an order morphological filter is formed, which selects appropriate structure element and percentile. Characteristics of transient power quality disturbances can be detected exactly when it passes through positive, negative d-q transformation and order morphological filter. Simulation results show that this method has favorable veracity and dynamic response characteristic.
Key words: dynamic power quality；double d-q transformations; order morphological filter；ATP-EMTP

Early detecting of fault arcs using Lyapunov exponents
YANG Jian-hong, ZHENG Ren-cheng, FANG Huai-ying
(Huaqiao University, Quanzhou 362021, China)
Abstract: In electric power system, fault arcs are disastrous trouble. At the present time, the protect projects of arc faults have certain shortcomings, with which burning arcs generation can not be avoided. Characteristic signals of fault arcs are studied systematically. Arc light, short-circuit current and arc sounds are primary associated signals of fault arcs. Simulation experiments indicate that sound signals can be found before generating arc faults. The phase space of chaotic time series of pre-arc sounds is reconstructed. Threshold value of inner-signals of chaos detection system is determined based on model LE method. The method of detecting pre-arc sounds based on Lyapunov exponents can extract and quantitatively identify pre-arc sounds inundated in the background complicate noise. If the value of maximum Lyapunov exponents is positive, there are pre-arc sound signals, otherwise there are not. Algorithm of early warning of pre-arc phenomenon is given based on pre-arc sound signals. The paper gives criterion of quantitative detection of pre- arc phenomenon.
Key words: fault arcs; Lyapunov exponents; pre-arc sounds; chaos; threshold value

Study on coupling characteristics and compensation of transcutaneous energy transmission system for artificial heart
CHEN Hai-yan, GAO Xiao-lin, YANG Qing-xin, LI Jun-bo
（Hebei University of Technology, Tianjin 300130, China）
Abstract: The earlier artificial heart was implanted in the body which was supplied by external electric power. It is connected with battery by the wires that penetrate the skin, which is easy to cause lethal infections. Transcutaneous Energy Transmission System（TETS） is used to power an artificial heart．This system uses the technic of contactless transformer．It does not require wires that penetrate the skin to send power inside the body, thus prevents the patients from infection-associate syndromes. This paper introduces the structure and principle of Transcutaneous Energy Transmission System．The effect that the core shape and dimensions have on the coupling change characteristics is analyzed．One type of high coupling and small size coil is proposed in this paper. Finally, compensation is studied and verified. The results of the paper provide academic basis for TETS research.
Key words: artificial heart；contactless power supply；TETS；coupling factor；compensate

Study of bubble development in transformer oils based on PD measurement in negative point-plane gaps
LI Jun-hao, SI Wen-rong, BI Hai-tao, LIU Jiong, LI Yan-ming
(School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
Abstract：Partial discharges, which take place in insulating oils, appear in the form of pulse bursts that consist of a series of discrete current pulses. The first pulse of pulse bursts is due to the initial streamer in the liquid phase, and all subsequent pulses will be the PD pulse responses in the growing bubble. The time interval between the first and second pulses is the formation time of bubble. The whole time of pulse bursts is the existing time of bubble in oil. The pulse burst characteristic and V-Φ Pattern in 25# transformer oil is measured using UWB measuring system and TECHIMP PD detector. The development process of pulse bursts in transformer oil is studied. The development time and formatting time in difference voltage are studied in this paper.
Key words: PD; oil insulation; bubble in oil; UWB; development times; formatting times

Analysis of striking mechanism of high voltage-doubling rectifier with square waves
FENG De-ren1, Guo Hong1, WANG Xiang-qi2, HAO Hao2, HONG Yi-lin2, PEI Yuan-ji2
(1. Anhui University of Technology, Maanshan 243002, China;
 2. National Synchrotron Radiation Lab., USTC, Hefei 230029, China)
Abstract: The high voltage-doubling rectifier is often applied in the acceleration class of the electron accelerator systems, etc. When square wave passing through pulse transformer is chosen as feed voltage, due to the abundance of the harmonics of the square waves, some kinds of them may resonate with the LC circuits of the leak-inductance and the capacitance of the high voltage-doubling systems, thus result in instant high voltage，that will cause the phenomenon of striking or breakthrough of devices such as diodes and electric capacitors, etc. This paper analyzed the mechanism of the striking of the 240kV high voltage-doubling system with square waves, and proposed the strategy for the monochromatic sine waves to be used for the charging voltage.
Key words: Fourier expansion; resonant; voltage-doubling rectifier; series resonance inverter

Experimental measurement and analysis of cyclotron wave microwave rectifier
CHEN Sheng-qian, WANG Zhi-xiong, HUANGg Jian-ren, ZHANG Zheng-qi
 (Telecommunication Engineering Institute, Air Force Engineering University, Xian 710077, China)
Abstract: An experimental sample of cyclotron wave microwave rectifier which is based on the resonance absorption of microwave energy by fast cyclotron electron beam wave has been developed successfully in China firstly. The output power of the sample reaches approximately 3W, and the efficiency of resonator; conversion region and collector is more than 70% respectively. It works stably and has the ability of self-protection against microwave or dc overloads and can rapidly recover from overloads. Through the test of this experiment, the technical feasibility of designing a cyclotron wave microwave rectifier is confirmed and its crucial technology is clarified, and it becomes the foundation of developing a new cyclotron wave microwave rectifier in the order of 1kW.
Key words: cyclotron wave microwave rectifier; microwave power transmission; wireless power transmission; solar power satellite

Method of checking competition risk in relay circuits based on logic simulation
ZHANG Ying-yao, GENG Ying-san, ZHANG Guo-gang, DENG Yong-qing
(State Key Lab of Elec. Insulation & Power Equipment, Xi’an Jiaotong University, Xi’an 710049, China)
Abstract: Relay system is one of the most broadly used control systems. Relay circuit design is a key part of relay system. CAD software, even those specifically created for relay circuit design, has no effective support to simulate relay circuits, and it is problematic because it requires manual analysis and verification, which wastes valuable design time and introduces design errors inevitably. The research and development of relay circuit simulation software is a significant and valuable work. In this paper, relays’ model classified according to their functions and their models are established. Relay control circuit is understood as a topography. The method of checking the competition risk is based on the simulation of the delay circuit according to the models.
Key words: relay circuit；simulation；competition risk