Construction of energy sustainable development system and development of new electric technology

In our country the problem of energy resources becomes more prominent day by day in the economy and social sustainable development and in the construction socialism harmonious life. Along with reduction of coal, increasing the renewable energy and the nuclear power direction, establishment of the energy sustainable development system have been considered. This article introduced briefly the energy sustainable supply system conception of the first half of the 21st century of our country formed in recent years and the corresponding suggestions, and the prime development direction of new electric technology was also summarized. 3 Refs. In Chinese.
Key Words: energy; sustainable development system; electric power　
YAN Lu-guang (Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 10080, China) // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 1—9.

Multi-objective optimization lexicographical algorithm of HAVC system and its application to Northeast power grid

HAVC (Hybrid automatic voltage control) system could achieve optimal control of the voltage and reactive power by adjusting the generators, OLTCs, capacitors and reactors in the power grid, and guarantee the safe, economic and high quality operation of the system. This paper gives a multi-objective optimization lexicographical algorithm which could be used in the HAVC system. This algorithm could coordinate these three objectives of voltage quality, voltage security and economy, and control the voltage and reactive power level of the system at an ideal state. The software has been developed according to this algorithm, and the test run in the HAVC system of Northeast 500kV power grid has proved that this algorithm is reasonable and effective. 14 Refs. In Chinese.
Key Words: HAVC; multi-objective optimization; lexicographical algorithm
XIE Bang-peng (State Key Lab of Power Systems, Dept. of Electrical Engineering, Tsinghua University, Beijing 100084, China), ZHANG Xue-min, MEI Sheng-wei, NI Xiang-ping // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 10—15.

Research and engineering application of a novel high-capacity shunt hybrid injection type active power filter

A novel shunt hybrid injection type active power filter (HSHIAPF) was designed to meet the integrated requirements of high-capacity harmonic restraint and reactive power compensation in substations and industrial enterprises. The topology structure of HSHIAPF was very suitable for dynamic harmonic restraint in high voltage and large capacity situations, and the passive part of HSHIAPF could also provide much reactive power. Moreover, the initial investment was also small. The principle of HSHIAPF was introduced in detail, and then, a sliding-window and iterative harmonic current detection algorithm and a slide-model variable structure control strategy based on the recursive integral PI algorithm were adopted to improve the response-speed and control-precision of HSHIAPF. The application results in the 220kV substation have shown the good performance and attractive prospect of HSHIAPF. The given methods and engineering experience are useful for applications and research of other active power filters. 7 Refs. In Chinese.
Key Words: active power filter; reactive power compensation; shunt hybrid injection type; harmonic current detection; variable structure control
ZHOU Ke (Guangxi Electric Power Test & Reasearch Institute Limited Company, Guangxi Nanning 530023, China), LUO An, CHU Hong-bo // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 16—20.

Simulation of coil and projectile in reconnection electromagnetic launch
ZHAO Chun1, ZOU Ji-yan2, HE Jun-jia1, LI Xiao-peng2
(1. Pulse Magnetic Field Lab, College of Elec. and Electronic Eng., Huazhong University of Science and Technology, Wuhan 430074, China;
2. Department of Electrical and Electronic Engineering, Dalian University of Technology, Dalian 116024, China)
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 21—24.
Abstract: The reconnection electromagnetic launch is a form of electromagnetic launch that utilizes the magnetic field line reconnection to accelerate a projectile. It has the advantages of no contact between the projectile and the coil and no erosion. A three-dimensional simulation model of the reconnection electromagnetic launch is established by means of the ANSOFT software for electromagnetic field finite element analysis. Simulative computations of the coil magnetic field, the projectile eddy current and the projectile electromagnetic force are performed. The influences of the coil and the projectile shapes on the launch effect are also analyzed. The simulations show that the existence of the projectile eddy current changes the distribution and the magnitude of the initial magnetic field of the coil. The maximal electromagnetic force on the projectile mainly depends on the force action area on the projectile in the motion direction. The larger the area is, the stronger the force is. The projectile with the linear rear edge is better in the electromagnetic force than that with the circular rear edge.
Key words: reconnection electromagnetic launch; electromagnetic analysis; finite element simulation

Experimental research of open channel evaporative cooling of turbo generator’s rotor windings

In order to apply evaporative cooling technology to large capacity turbo generator，evaporative cooling technology of rotor needs thorough research. This paper introduces the simulating experiment of open channel evaporative cooling of turbo generator’s rotor windings, stating the theory of experiment and construction of experimental model and acquiring of data, and analyzing the results in detail. The aim of experiment is to obtain the temperature distribution of open channel rotor winding. The results indicated an even temperature distribution in radial direction. That completely conformed with the cooling specification of turbo generator. Under different working conditions, the system showed great cooling ability. This experiment provided basis for the design and computation of large capacity turbo generators which adopted open channel evaporative cooling technology of rotor winding and had certain guiding significance to the next step of experimental work. This experiment also provided experimental basis to the research of fluid flow and heat transfer under centrifugal force. 10 Refs. In Chinese.
Key Words: turbo generator; evaporative cooling technique; rotor cooling; open channel; rotating model
HOU Zhe (1. Institute of Electrical Engineering, CAS, Beijing 100080, China; 2. Graduate Univ. of CAS, Beijing 100039, China), YAO Tao, GU Guo-biao // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 25—29.

AC loss modeling for multi-turn parallel PCB winding of high-frequency power planar transformer

Parallel PCB winding is a good solution for high-frequency, high-current and high power density planar transformers of switching-mode power supply. However, the current handling capability of the parallel PCB winding depends on its reasonable design. Uneven current sharing among parallel PCB layers of the winding makes the winding loss model and the design complicated. Comparing to the single-turn parallel PCB windings, the multi-turns or series- and parallel-hybrid connection PCB winding has more complicated loss model and its design. Based on voltage balance of circuit loop consisted by parallel PCB layers, the analytical loss model was built for the multi-turns PCB winding including rectangular- and circular- structure. Experiments verify the loss model. 11 Refs. In Chinese.
Key Words: planar transformer; parallel PCB winding; AC winding loss; power conversion
MAO Xing-kui (College of Electrical Engineering& Automation, Fuzhou University, Fujian Fuzhou 350002, China), CHEN Qing-Bin, CHEN Wei // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 30—34. 

A novel harmonic current detecting algorithm
RONG Fei, LUO An, FAN Qing
(1. College of Electrical and Information Engineering, Hunan University, Changsha 410082,China; 2. Changsha Zoomlion Heavy Industry Science ＆Technology Development CO,. Ltd., Changsha 410013, China)
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 35—39.
Abstract: To counter the shortages when using the traditional  coordinate transformation method to detect sequence components, a new detection method which is suitable for both the unbalanced load system and the unbalanced source system is presented in this paper. The new method utilizes the single phase voltage to obtain the synchronous rotating angle without the need of circuit of Phase Lock Loop (PLL) to obtain synchronous rotating angle, so eliminates the influence brought by the time delay of PLL. Furthermore, the new method needn’t to compute the trigonometric function too, so reduces the complexity. At last, the design procedure of the differential which is used in the new method is introduced in this paper. The simulation analyses results indicate that the proposed method has the characteristic of high precision and rapid response when detecting the positive sequence, negative sequence and distortion components of the load current under the unbalanced and distorted source.
Key words: detection; unbalanced system; negative sequence; STATCOM; synchronous rotate angle

Spatial load forecasting based on load decomposition and support vector machine

A new spatial load forecasting (SLF) model for distribution network is proposed. First, the characteristics of different kinds of power load are analyzed, then the appropriate forecasting methods are chosen and the forecasting accuracy are improved. Dividing the selected field into same small areas, extracting the spatial information of the small area, using principal component analysis method to conduct the spatial information of the well-rounded small area to form the training sample of the support vector machine, the attribute values of the small areas in the forecasting field are then calculated by the trained support vector machine, so the order table of the different field are formed. Based on the forecasting results and the development plan of the forecasting field, the incremental load and the different load density are attained, so the total amount of different fields can be calculated, at last the spatial forecasting results can be obtained under the former order table. Finally, this model is implemented and the analysis result for practical calculation example by this model is satisfied. 6 Refs. In Chinese.
Key Words: spatial load forecasting; load subdivision; principal component analysis; support vector machine
LI Jin-chao (School of Business Administration, North China Electric Power University, Beijing 102206, China), NIU Dong-xiao, LI Jin-ying, et al. // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 40—43.

Anticontrol of chaos in DC motor
GUO Lu-su, CHEN Ji-he
(Department of Electrical Engineering, Tsinghua University, Beijing 100084, China)
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 44—46.
Abstract: Mixers are widely used in many industrial applications, but they are among the most expensive and ineffective equipments. In this paper, an experimental device for industrial mixing is introduced. Its motor drive is controlled into chaotic motion, which is called “chaotification”. This paper presents a novel method of anti-control of motors by introducing “Logistic” mapping to motor equations. Computer simulation proves that this anti-control method can drive the PMDC motor into chaotic running motion. Chaotic motor speed waveform and its spectrums are also discussed. Furthermore, chaos characteristics like Lyapunov Exponents and Poincaré maps are calculated and developed to identify chaotic behavior, which are helpful in designing suitable industrial control parameters. This paper presents two practical numerical algorithms to calculate chaotic system’s Lyapunov exponent, which are the direct method using variation equations and the method using system sampling data. In the end, chaotic system’s parameter bifurcation graphics are also plotted.
Key words: chaotification; PMDC motor; logistic mapping

Research on magnetic field of current transformer under uniformly-distributed equal Ampere-turns test

The uniformly-distributed equal ampere-turns test, which concentrates the primary turns on one part of the current transformer’s core, was presented to measure the error of current transformer in actual working environment. However, there’s few or no special research on this method of test at home and abroad up to now. In this paper, 3D non-working magnetic field and resultant magnetic field of current transformer’s core under uniformly-distributed equal ampere-turns test are solved with 3D finite element method to reveal the principle of this method of test. The trends of these magnetic fields about primary turns’ concentrated angle on current transformer’s core are also analyzed. It has indicated that the magnetic field of current transformer’s core caused from the change of primary turns’ concentrated angle on the core could simulate the stray magnetic field of the core caused from the external currents and short circuit fault. 6 Refs. In Chinese.
Key Words: current transformer; equal ampere-turns; magnetic field
ZHANG Hao (State Key Lab of Power Systems, Dept. of Elec. Eng., Tsinghua University, Beijing 100084, China), ZHAO Wei, QU Kai-feng, et al. // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 47—50.

Transient character of XLPE cable winding under thunder surge
LEI Lang, LV Liang, MENG Zheng-zheng, YUAN Jian-hua, LI Yan-ming
(Xi’an Jiaotong University, Xi’an 710049, China)
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 51—54.
Abstract: The transient circuit of import characteristic of XLPE cable winding is solved. The higher discharge-voltage and residual voltage of arrester is the higher voltage of cable winding. The steep thunder surge and the larger entrance capacity makes the voltage of cable winding lower than the residual voltage of arrester, and it is advantageous to the protection of cable winding. This phenomenon is different from that of the traditional winding. It provides a theoretical basis for the design, protection and testing of this new type of power transformer.

A review and future prospects of renewable energy in the global energy system

Global energy consumption in the last half century has rapidly increased and is expected to continue to grow over the next 50 years, however, with significant differences. The past increase was stimulated by relatively “cheap” fossil fuels and increased rates of industrialization in North America, Europe and Japan; yet while energy consumption in these countries continues to increase, additional factors make the picture for the next 50 years more complex. These additional complicating factors include China and India’s rapid increase in energy use as they represent about a third of the world’s population; the expected depletion of oil resources in the near future; and, the effect of human activities on global climate change. On the positive side, the renewable energy (RE) technologies of wind, bio-fuels, solar thermal and photovoltaics (PV) are finally showing maturity and the ultimate promise of cost competitiveness. 22 Refs. In English.
Key Words: global energy consumption; renewable energy; energy demand; energy conservation 
GOSWAMI D Yogi (Clean Energy Research Center, University of South Florida, Tampa, Florida 33620, USA) // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 55—62.

Transformer derating and comparison of harmonic loss factor FHL with K-factor
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）
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 63—66.
Abstract: The transformer losses will increase when operating under harmonic load conditions. The derating measure is always taken to limit the temperature of windings or top-oil. Based on introduction of two harmonic loss factors, K-factor and FHL, and the equations of the total losses of transformer, this paper reasoned out the difference of the computed maximum permissible rms non-sinusoidal load current of derating using the harmonic loss factor FHL and K-factor. Keeping within the rated power loss limits, maximum permissible rms non-sinusoidal load current using K-factor approach is relatively conservative because derating winding eddy current losses is replaced with pre-derating ones. The harmonic loss factor FHL is a function of the harmonic current distribution and is independent of the relative magnitude. Maximum permissible rms non-sinusoidal load current using FHL approach is relatively economical for taking account of actual operating harmonic current. The relationship of two harmonic loss factors and their application were also discussed in this paper.
Key words: transformer; harmonic current; losses

Single phase system control and modeling of bidirectional AC/DC converters

Both “method of average value separated” and “method of half cycle averaging” which are applicable to system control modeling of single phase bidirectional AC/DC converters are proposed in accordance with their state space averaging model and characteristic of output waveforms. Both transfer function model and discrete control model as concerns the ac-side current amplitude and the dc-side output voltage are derived from theoretical analysis and linearization processing. Also some steady state quantitative relations are derived out. All of these provide basis for system design. The validity of the control models and theoretical analyses is confirmed by sample equipment experiment results. 7 Refs. In Chinese.
Key Words: single phase bidirectional AC/DC converters; modeling method; transfer function; discrete control model
ZHANG Jia-sheng (China University of Petroleum, Shandong Dongying 257061, China), LI Hao-guang // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 67—71.

Error compensation system for optical current transformer based on wavelet analysis and neural network
LIU Ye 1， CHEN Jing-hou 1，FAN Yan-fang2，ZHANG Kan-kan1，CHEN Jiang-bo1，SHU Xiu-mei1，MA Zhi-ying1
(1. School of Electric Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
2. School of Electric Engineering, XinJiang University, Wulumuqi 830008, China)
// Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 72—75.
Abstract：Basic principles of optical current transducer based on Faraday effect and the influence to system by linear birefringence effect are introduced. By combining the good steady performance of conventional current transformer and the unsaturated characteristic of optical current transformer, an error compensation system for optical current transformer based on wavelet analysis and neural network is designed. Here wavelet analysis is used to detect power system fault moment so as to distinguish between transient and steady state and neural network is used to compensate linear birefringence effect. Experiments show that the error compensation system plays a good effect in error compensation for optical current transformer, and increases the stability and the accuracy of the optical current transformer.
Key words：optical current transformer; linear birefringence effect; wavelet analysis; neural networks; mathematical modeling

Study and application of unity power factor elevator energy- regeneration system based on improved phase and amplitude control

Considering the disadvantages of ordinary elevator transducer that it cannot utilize the regeneration energy，this paper designs a 15kW elevator energy-regeneration equipment which can connect with elevator transducer easily based on phase and amplitude control. It realizes unity power factor operation and can control input DC voltage. On this foundation, in view of features that the elevator starts and stops frequently, the ideal starting time parameter and the value of feed forward adjustment when input power changes are deduced using the rate of change of input DC voltage and the regulation time of the system is shortened. The test in Shanghai Mitsubishi Elevator Ltd. indicates that the energy-regeneration equipment has the advantage of good in static and dynamic characteristics. 8 Refs. In Chinese.
Key Words: energy-regeneration; phase and amplitude control; unity power factor; prediction; feed forward
MA Yi-wei (Shanghai University, Shanghai 200072, China), LI Jie, CHEN Guo-cheng, et al. // Adv. Tech. of Elec. Eng. & Energy, 2008, 27(1). 76—80.