Smart grid oriented large⁃scale compressed air energy storage technology
CHEN Lai⁃jun1, MEI Sheng⁃wei1, WANG Jun⁃jie2, LU Qiang1
(1. State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical
Engineering, Tsinghua University), Beijing 100084, China; 2. Key Laboratory of Cryogenics,
Technical Institute of Physics and Chemistry, CAS, Beijing 100190, China)
Abstract: Wind, solar and other types of new energy sources are volatile and intermittent, and large⁃scale develop⁃
ment and utilization of those new energy introduces a serious challenge to the security and stability of the power sys⁃
tem operation. Large⁃scale energy storage is known as the most effective way to solve this problem. The compressed
air energy storage (CAES) is expected to be the best choice in all the large⁃scale energy storage techniques con⁃
cerning the aspects of economy, technology maturity and environmental impact. The concept of electricity grade and
energy storage efficiency is proposed to reach an in⁃depth understanding of the advantages and disadvantages of dif⁃
ferent energy storage means. The development of compressed air energy storage is briefly reviewed and the non⁃af⁃
terburning CAES technology adopted in the 500kW demonstration project of State Grid Corporation is introduced.
Then, the prospects of potential applications of CAES are pointed out and the key technologies need to be studied
are discussed, so as to promote large⁃scale application of the CAES in the smart grid.
Key words: new energy integration; electricity grade; compressed air energy storage; smart grid
Power system load forecasting based on quantum behavior
particle swarm optimization algorithm⁃chaotic neural network
WANG Bing⁃shan1, ZHOU Bu⁃xiang1, XIAO Xian1, LIN Nan2
(1. School of Electrical Engineering and Information, Sichuan University, Chengdu 610065, China;
2. Sichuan Electric Power College, Chengdu 610071, China)
Abstract: This paper presents a combinative method of power system load forecasting based on quantum behavior
particle swarm optimization and chaotic neural network. Based on the quantum behavioral characteristics of the par⁃
ticle swarm, and using the identical particle system to update the particle’s position, the shortcomings of the tradi⁃
tional particle swarm optimization, such as low accuracy, dissipation easy, and slow convergence rate can be avoi⁃
ded. Using particle swarm optimization algorithm to optimize the chaotic neural network weights and thresholds, we
can overcome the shortcomings that it is difficult and slow to determine the parameters of chaotic neural network. U⁃
sing the weights and thresholds, through the improved particle swarm optimization algorithm⁃chaotic neural network
model, the corresponding time load value of the predicting date can be obtained. Finally, through the practical ap⁃
plication, it can be proved that the method has higher prediction accuracy and better accuracy, with some practical
value.
Key words: quantum behavior; particle swarm; identical particles; chaotic neural network; load forecasting
Static voltage stability analysis of power systems with wind farm groups
LIU Wen⁃xia1, WU Fang⁃quan2
(1. Grid Planning & Research Center, Guizhou Power Grid Cooporation, Guiyang 550003, China;
2. Yunnan Honghe Electric Power Supply Bureau, Honghe 661000, China)
Abstract: High penetrations of wind farm groups will produce certain effect on power system’s safety and stablili⁃
ty. In order to analyze the static voltage stability of power system with wind farm groups, this paper applies inverse
Nataf transformation to build correlated wind speed of wind farm groups, and wind farms which are equalized as
wind turbines will connect to PQ buses as negative loads. Continuous Power Flow will compute system’s voltage
collapse points which are served as load margin in different wind speed correlation coefficients so as to analyze static
voltage stability. The case study on the improved IEEE⁃14 and IEEE⁃30 buses system demonstrates the effectiveness
of the method, and it provides certain reference to power system analysis and operational control.
Key words: continuous power flow; wind farm groups; inverse Nataf tansformation; Monte Carlo simulation; static
voltage stability; load margin
Design of Terminal piecewise sliding mode excitation
controller based on improved PSO
ZHANG Hong, YU Lei, XU Bin
(College of Electrical Engineering, Northeast Dianli University, Jilin 132012, China)
Abstract: In order to obtain better convergence rate, Terminal piecewise sliding mode excitation control is designed
based on fast terminal sliding mode surface. Sliding mode control strategy contains more parameters, so that to solve
this problem, particle swarm optimization (PSO) is used to optimize the parameters for the preferable ability of
searching. The simulation and analysis are done under a variety of disturbance based on single machine to infinite⁃
bus system. The simulation results show that the response rate of the control strategy proposed in this paper is fas⁃
ter, and it can also improve the static and transient stability of the power system effectively and improve control pre⁃
cision.
Key words: Terminal piecewise sliding mode; particle swarm optimization; excitation control; single machine infi⁃
nite system
Selective⁃harmonic active power filter using complex vector
PI current regulator
ZHONG Chang, YOU Xiao⁃jie, GUO Xi⁃zheng
(School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China)
Abstract: Three⁃phase Shunt Active Power Filter (SAPF) is a power electronic device compensating the harmonics
and inactive power produced by non⁃linear load in the power system. And its compensation performance is primarily
decided by the control accuracy and dynamics of the current regulator. In this paper, a complex vector PI current
regulator is introduced which has decent robustness for system parameters. In order to eliminate influences of the
intrinsic delay in the digital control system on the stability, a method for compensating the delay by advancing the
phase of voltage command is employed. Additionally, the virtual resistance method is proposed for the sake of en⁃
hancing the stiffness of system and improving the accuracy of selective harmonic compensation. Finally, simulation
tool is used to validate the proposed method.
Key words: SH⁃APF; delay compensation; complex current regulator; virtual resistance method
Commutation analysis of three⁃phase Z⁃source inverter
LI Jie1, QU Ke⁃qing2, LI Zhan⁃wei1
(1. Shanghai Open University, School of Information and Engineering, Shanghai 200433, China;
2. Shanghai University of Electric Power, School of Electric Power and
Automation Engineering, Shanghai 200090, China)
Abstract: The three⁃phase Z⁃source inverter has 9 switching states, so its commutation is complicated relatively. In
this paper, according to the properties of IGBT and snubber circuit in the phase leg, commutation process of the
three⁃phase Z⁃source inverter is analyzed in detail by illustrations. The results of experiment on the Permanent Mag⁃
net Synchronous Generator (PMSG) wind generation system based on three⁃phase Z⁃source inverter verify the cor⁃
rectness of the analysis.
Key words: three⁃phase Z⁃source inverter; commutation analysis; snubber circuit
Dual⁃redundancy fault tolerant permanent magnet motor control system
HUANG Yi⁃hong, HAO Zhen⁃yang, MU Xiao⁃jing
(Jiangsu Key Laboratory of New Energy Generation and Power Conversion (Nanjing University
of Aeronautics and Astronautics), Nanjing 210016, China)
Abstract: In this paper, compared with traditional fault⁃tolerant system and traditional redundancy system, a con⁃
trol strategy of dual redundant motor system applied in fault tolerant permanent magnet motor with dual⁃winding is
analyzed. A fault⁃tolerant permanent magnet machine of centralized winding is introduced, which has the property
of physical insulation, magnetic flux and fault insulation. And vector control is adapted in this system. The Matlab
simulation model is established which contains the motor model, SVPWM, speed controller, three⁃phase full⁃bridge
inverter and current controller. The simulation results reveal that the constant speed mode and constant torque mode
can be switched in the dual⁃redundancy control system. Experiment results show that the speed is constant when the
load torque changes under constant speed mode, and the torque is constant when the speed changes under constant
torque mode. Both the simulation and experiment results show that fault⁃tolerance control of the system is achieved
when open⁃circuit fault occurs while maintaining the power and speed unchanged. Key words: fault⁃tolerant permanent magnet motor; dual⁃redundancy control; vector control; redundancy switc⁃
hing
Analysis on capacitive reactive power compensation of controlled
reactor of transformer type with harmonic⁃compensation winding
GU Sheng⁃jie1,2, TIAN Ming⁃xing2
(1. Ministry of Education Key Laboratory of Opto⁃Electronic Technology and Intelligent Control
of Lanzhou Jiaotong University, Lanzhou 730070, China; 2. School of Lanzhou
Automation & Electrical Engineering of Lanzhou Jiaotong University, Lanzhou 730070, China)
Abstract: Controlled reactor of transformer type with harmonic⁃compensation winding is studied in this paper based
on the analysis of the windings arrangement and harmonic characteristic. The ratio of capactive current that is de⁃
rived from nth LC fitlers to nominal curent of single phase is obtained when thyritor branch is open and reactive
power capacity of LC filter is minimum. All analyses show the capacitive reactive power compensation of the CRT.
The MATLAB model of the three phase CRT is built to verify the capacitive reactive power compensation character⁃
istic, and the U⁃Q characteristic of CRT is also analyzed. The results demonstrate that the theoretical analysis is ef⁃
fective.
Key words: controlled reactor of transformer type; short circuit reactance; harmonic; LC filters; minimum reactive
power capacity; capacitive reactive power compensation
Method for calculating minimal load margin constrained
by power system transient stability
CHANG Nai⁃chao, TAO Hong⁃zhu, GUO Jian⁃cheng, XIN Yao⁃zhong
(State Grid Corporation of China, Beijing 100032, China)
Abstract: In order to consider the effect of different load⁃generation increasing directions to the load margin con⁃
strained by power system transient stability, an optimization model for calculating the minimal load margin con⁃
strained by power system transient stability is proposed. The stability quantitative index proposed by the improved
PEBS method is used to construct the transient stability constraint, and it has the same model adaptation as the time
domain transient simulation method. A numerical method for solving the proposed optimization model is given out
based on the basic theorem about the distance from a point to a curved surface. The basic idea of the proposed solu⁃
tion method is that the normal vector at the critical point of the power systems transient stability boundary surface is
taken as the load⁃generation increasing direction in the iterative solution procedure, and the minimal load margin
constrained by power systems transient stability is finally acquired. Theoretically, the proposed model and method
can also be applied to calculating the maximal load margin constrained by power system transient stability, and all
kinds of power system operating constraints can also be considered. A numerical example verifies the proposed mod⁃
el and method. Key words: transient stability; load margin; power systems
Realization of positive characteristic self⁃regulated
current restraint resistance
ZHANG Yuan⁃sen1, ZHANG En⁃ping2, LIU Zhi⁃yong1, WANG Ze⁃zhong3,
ZHANG Dong⁃feng1, LIU Jian1, LV Fen⁃fei1
(1. Dezhou Power Supply Company, Dezhou 253000, China;
2. School of Electrical Engineering, University of Jinan, Jinan 250022, China; 3. School of Electrical
& Electronic Engineering, North China Electric Power University, Beijing 102206, China)
Abstract: Field test running has proved that injected direct current line selection and location method is very effec⁃
tive in the single⁃phase grounded fault line selection and location of the small current grounded system, and the di⁃
rect current generator takes a very important role in the realization of this fault line selection and location method.
The direct current generator is made up of rectifier part and current restraint resistance. A realization of current re⁃
straint resistance based on PTC positive characteristic of self⁃regulation is proposed in this paper, in which a posi⁃
tive character self⁃regulated resistance network element based on PTC element and paralleled constant value resist⁃
ance constitute a network element, and several serial connected network elements constitute the positive characteristic self⁃regulated current restraint resistance which can successfully regulate the direct current value self⁃adaptively
according to the change of value of neutral to ground voltage. This paper has made a detailed theoretical analysis to⁃
wards this method and its principle of implementation, and the simulation and experiment in the lab has proved this
method is effective.
Key words: single⁃phase grounded fault; line selection method based on injected direct current; direct current
generator; self⁃regulated current restraint resistance; PTC
Application of electromagnetism⁃like mechanism
in short circuit current limiting optimization
LEI Qing1, ZHOU Bu⁃xiang1, LIN Nan2, YE Zong⁃bin1, KONG Xiang⁃cong1
(1. School of Electrical Engineering and Information, Sichuan University, Chengdu 610065, China;
2. Sichuan Electric Power College, Chengdu 610071, China)
Abstract: Electromagnetism⁃like mechanism(EM) is a stochastic global optimization algorithm. It simulates the
mechanism of attraction and repulsion in the electromagnetic field, assimilates each solution to a charged particle,
and according to certain criteria makes the search particles move towards the optimal solution. In this paper, we
improve the algorithm: using uniform design method makes the initial population more uniform; using chaotic opti⁃
mization for local search makes convergence acceleraed; and calculation of force and particle update also makes
some improvements. Finally the improved EM algorithm is used in the optimal configuration of current limiting
measures. The algorithm for solving the discrete variable and nonlinear constraint optimization problem has the ad⁃
vantage of convenience and high efficiency, and it makes current limiting optimization to have good convergence
and global optimization ability. The calculation and result analysis of New England 39 nodes system show that the
proposed algorithm has better global searching capability, high efficiency, and can get good results. Key words: electromagnetism⁃like mechanism; short circuit current limiting; power system; search space
Resonance characteristics and its impact factors of reradiation interference
on radio station from UHV power lines
TANG Bo1, ZHANG Jian⁃gong2, WANG Hui⁃li3, GE Guang⁃zu1, LIU Xing⁃fa2
(1. College of Electronic Engineering & New Energy, China Three Gorges University, Yichang 443002, China;
2. China Electric Power Research Institute, Wuhan 430074, China;
3. Sanmenxia Power Supply Company of Henan Electric Power, Sanmenxia 210098, China)
Abstract: There is the resonance phenomenon in the reradiation interference on radio station from UHV power
lines. IEEE gives the resonance mechanism and its frequency at the frequency band of 535 ~1705 kHz. In order to
research the resonance characteristics of reradiation interference at higher frequency, the wire⁃surface simulation
model excited by vertical polarization plane wave, in which steel tower is represented as surface model and ground
wire is represented as wire model, is used. Based on the method of moments (MoM), the base function of wire⁃
surface model junction point and the computation method are discussed, and the interference values are calculated
at the frequency band of 0 5 ~ 50 5MHz. The possible impact factors of interference resonance, such as ground
wire, conductor, number of towers and tower spans, are studied. The results show that the decisive impact factor
on reradiation interference is tower spans.
Key words: UHV power lines; reradiation interference; resonance characteristics; wire⁃surface model; method of
moments; impact factor
DC⁃biasing experiment and analysis of DC⁃biasing characteristics
based on single⁃phase three⁃limb transformer
ZHAO Xiao⁃jun1, LI Hui⁃qi1, ZHANG Xiao⁃xin1, LIU Yang1, CHENG Zhi⁃guang2
(1. Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense,
North China Electric Power University, Baoding 071003, China;
2. Tianwei Group Co. , LTD. , Baoding 071056, China)
Abstract: Magnetizing characteristics of power transformer and normal operation of power grids are affected by the
quasi⁃direct current and the direct current caused from the solar magnetic disturbance and the HVDC system respec⁃
tively. In order to study DC⁃biasing characteristics of power transformer, a single⁃phase three⁃limb transformer is
applied to carry out the DC biasing experiment in this paper. The measured magnetizing current are analyzed to
study the influence of DC bias on harmonic components of magnetizing current. The iron loss are measured and ana⁃
lyzed under DC⁃biased magnetization. The measured results indicate the DC bias current has a great influence on
hysteresis and excitation characteristics. The DC magnetic flux is related to the DC bias current and the excitation
voltage by combining experimental results and theoretical deduction. Analysis of DC⁃biasing magnetizing character⁃
istics is of great engineering significance on the safe operation of the power system, the design and manufacture of
the power transformer.
Key words: power transformer; DC bias; DC magnetic flux; magnetizing characteristics
Study of transformer inductive oscillating switching impulse
voltage generation method based on IEC60060⁃3 standard
LIANG Jian⁃feng1, LI Jun⁃hao1, HOU Xin⁃yu1, WU Xu⁃tao2,
WANG Guo⁃li3, LI Yan⁃ming1
(1. School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, China;
2. Electric Power Research Institute of Ningxia Grid Corporation, Yinchuan 750002, China;
3. National Engineering Laboratory for Ultra High Voltage Engineering Technology (Kunming, Guangzhou),
Guangzhou 510080, China)
Abstract: The generation method of the transformer inductive oscillating switching impulse voltage based on the
IEC60060⁃3 standard is investigated in this paper. The circuit of the oscillating switching impulse voltage generated
through transformer induction is analyzed in theory and the formulas of generation circuit parameters are presented.
The generation circuit parameters can be evaluated by the time to peak, time to half⁃value and oscillating frequency
of the oscillating switching impulse voltage waveform. The computer simulation results show that the generated
waveforms meet the requirements of IEC60060⁃3 standard, and the formulas can accurately calculate generation cir⁃
cuit parameters by the oscillating switching impulse voltage waveform parameters. The experimental researches are
carried out in an 110kV power transformer with a single phase and two windings by the Haefely RSG 481, and the
experimental results reveal that the high voltage terminal of the power transformer can effectively generate the oscil⁃
lating switching impulse voltage which satisfies the requirements of IEC60060⁃3 standard by the Haefely RSG 481
input to the low voltage terminal of the power transformer.
Key words: IEC60060⁃3; oscillating switching impulse voltage; power transformer
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