Inner Mongolia Electrical Power Research Institute
Inner Mongolia Electrical Power Research Institute
Zhang Y.,University of Science and Technology Beijing |
Zhao J.,Inner Mongolia Electrical Power Research Institute |
Zhang F.,University of Science and Technology Beijing |
Wang J.,University of Science and Technology Beijing
International Journal of Robust and Nonlinear Control | Year: 2017
In this work, a new robust nonlinear feedback control method with dynamic active compensation is proposed; the active control method has been applied to an integral series of finite-time single-input single-output nonlinear system with uncertainty. In further tracking the closed-loop stability and nonlinear uncertainty, an extended state observer has been employed to solve the immeasurability and nonlinear uncertainty within a nonlinear system. A singular perturbation theory has been used to solve for the finite-time stability of the closed-loop system; furthermore, numerical simulations showed that the robust nonlinear feedback controller tracked the uncertainty in a nonlinear Duffing-type oscillator and has proven the effectiveness of the approximate finite-time control strategy proposed. By using an approximate finite-time control approach with active compensation, the uncertainty in a nonlinear system could be accurately estimated and controlled. © 2017 John Wiley & Sons, Ltd.
Hu Z.,Inner Mongolia University of Technology |
Ren Y.,Inner Mongolia University of Technology |
Han J.,Inner Mongolia Electrical Power Research Institute |
Xue Y.,Beijing Tian Run New Energy Investment Co.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2017
In order to reduce the influence of electric energy quality problems, such as voltage harmonic, voltage sag or swell, voltage unbalance, on the doubly-fed induction generator (DFIG) wind power system, a scheme of a nine-switch unified power quality conditioner (UPQC) applied to a DFIG wind turbine system is proposed after a contrastive study on the topological structures of various UPQCs and modeling analysis of nine-switch converter. On the basis of modeling the operation circuit of voltage and current compensation unit in UPQC, the corresponding control algorithm is designed. According to the power grid condition, 3 types of working scenario are set up to optimize the operation scheme of UPQC, including harmonic circuit compensation, mild voltage compensation, and heavy voltage compensation. Simulation and experiments are made to verify the validity of the scheme. The results show that, the nine-switch UPQC can suppress harmonic voltage and current, eliminate voltage deviation and phase jump to significantly improve power quality of DFIG, thereby realizing flexible fault ride-through (FFRT) in a wide range of fault voltage conditions. © 2017 Automation of Electric Power Systems Press.
Wu X.,Inner Mongolia Electrical Power Research Institute |
Minfu A.,Inner Mongolia Electrical Power Research Institute |
Hou B.,China Institute of Technology
2016 IEEE International Conference on Power and Renewable Energy, ICPRE 2016 | Year: 2017
This paper presents a new method to rank nodes in power systems in terms of how close the loads at those nodes are to the limit that the system can supply before voltage collapse occurs. This method is applicable to slow load fluctuation and static modeling is used. The method is based on the fact that the Jacobian Matrix becomes singular at the voltage collapse point. This paper focuses on calculating the maximum load margin at load buses before reaching voltage collapse gradually (static voltage instability). After get the limit of bus load, the load bus could be ranked.
Luo Z.-P.,Inner Mongolia University of Technology |
Liu Y.-H.,Inner Mongolia University of Technology |
Yang B.-F.,Inner Mongolia Electrical Power Research Institute
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014
This paper presents a novel MLCR-CSC-STATCOM topology, particularly suitable for the high power applications. Injection control technology, multi-level technology and zero level technology are used, which enables main bridge switch working in fundamental frequency to output continuous controllable AC current and high-quality current waveforms and meantime better resolve the absorption capacitance problems of conventional CSC without installing AC capacitor. This paper derives the mathematical model of MLCR-CSC-STATCOM, adopts feedback control linearization means for the affine CSC-STATCOM equations and replaces the nonlinear control design with linear state equation design. By use of PSCAD/EMTDC tools, the established model of MLCR-CSC STATCOM is simulated and some specific conclusions are drawn.
Liang G.,Inner Mongolia Electrical Power Research Institute
China International Conference on Electricity Distribution, CICED | Year: 2014
As the further growth in electricity using of Chinese urban residents, in order to meet the requirements of the city, more and more 220kV transformer substations have been constructed in the city as distribution substations. the character of such substations are: 220kV and 110kV high-voltage electrical equipment use GIS; substation area is small; the increasing power system capacity caused short circuit current of grounding fault growing. The outstanding issues of substation grounding design is that the ground area is small (5000 ∼ 10000m2), and soil resistance rate is high (normally 500 ∼ 1200Ω · m or higher). There is no external ground conditions laid and local geological conditions are poor, and soil receptivity is high. Substation using reducing agent make the grounding grid of substation corroded very serious; soil around the net salinity and soil moisture make serious corrosion of the grounding. © 2014 IEEE.
Zheng T.-T.,Inner Mongolia Electrical Power Research Institute |
Wang H.-X.,Dalian University of Technology
China International Conference on Electricity Distribution, CICED | Year: 2016
The asymmetry of electrified railway loads accessed to the power system would bring the harmonic waves and negative-sequence currents, giving rise to the distortion of voltage waves and the problems of power quality, such as the unbalance of the three-phase voltage. Combined with the project 'Power quality assessment of Bin-zhou railway electrification reconstruction project of the traction substation', this paper introduces a power quality forecast assessment method based on Power System Analysis Software Package (PSASP). Considering the railway load features, harmonic superposition characteristics and access way of traction stations, simulations are performed to analyze various power quality indexes of the point of common coupling (PCC) under different working conditions with traction loads station accessing to the system, then the power quality background test are performed for the substations of the traction station access point, the influence of electrified railway on the whole grid will be found according to the above two aspects. Results show that commutation by turns with traction stations accessing to the system has an offset effect on negative sequence current, and verify that the difference of traction load has various effects on the system. © 2016 IEEE.
Liang G.,Inner Mongolia Electrical Power Research Institute
2010 China International Conference on Electricity Distribution, CICED 2010 | Year: 2010
This paper discusses current grounding design issues of present electric power plants, transformer substations in high soil resistivity area, by incorporating the actual engineering data of a 220KV substation, analyzes the impact degree of grounding design parameters to earth potential, contact potential, and step potential. It also can be used as a reference point for peers to discuss in engineering design. © 2010 Chinese Soc for Elec Eng.
Zhao G.,Shandong University |
Chen H.,Shandong University |
Chen H.,Inner Mongolia Electrical Power Research Institute |
Zhang C.,Shandong University |
Guan Y.,Shandong University
International Journal of Advanced Manufacturing Technology | Year: 2013
The extrusion die plays a crucial role in aluminum alloy profile production, which influences product quality and service life of extrusion die directly. In this paper, a profile with irregular shape was taken as an analysis example, and multiobjective optimization for porthole extrusion die based on modern intelligence algorithm was carried out. Aiming at achieving the uniform velocity distribution in the cross-section of the profile as well as decreasing the maximum stress on the extrusion die and the deflection of the mandrel, the angle between port bridges, the position of die orifice, and the height of welding chamber were considered as the design variables. Then Kriging model was established on the basis of Latin hypercube samplings, and above design variables were optimized using Pareto-based genetic algorithm. Finally, an optimal die structure is gained. Compared with the initial scheme, the velocity distribution in the extrudate was more even, and the stress on the die and the deflection of the mandrel were decreased obviously in the optimal scheme. The optimal design method for porthole die has strong commonality, thus, it could give useful guidelines for practical production of the same kind of aluminum profile. © 2013 Springer-Verlag London.
Yang B.,Inner Mongolia Electrical Power Research Institute
Gaodianya Jishu/High Voltage Engineering | Year: 2012
To explore experimental methods and analysis means for the linear induction launcher, we designed and manufactured a linear induction launcher to carried out experimental research and simulation analysis. Moreover, we established a mesh matrix model of the linear induction launcher to analyze the dynamic performance of the secondary, voltage and current waveforms, the energy conversion ratio and the heating effect of currents. Using a two level voltage source inverter as power supply, we accelerated the launcher with a 0.275 kg aluminum alloy secondary to 18.75 m/s within the 0.96 m linear distance. The measured muzzle velocity accorded with the calculated muzzle velocity, and the measured voltage and current waveforms approximated the simulated ones. The experimental results show that the mesh matrix method can be used as an effective means to analyze the linear induction launcher. Experiment and simulation provide a reference for the further investigations of the inductive coil gun.
Zhao L.,Inner Mongolia Electrical Power Research Institute |
Cheng P.F.,Polytechnic University of Mozambique
Advanced Materials Research | Year: 2014
In this paper, the dielectric properties of ZnO- Bi2O3 based varistor ceramics doped with Li are investigated by Novocontrol wide band dielectric spectrometer. It is found that Lithium is an amphoteric impurity. If the content of Lithium is very low, It will enters into the interstitials and Lithium interstitial is formed as a donor. While with the increase of Lithium content, Zn is replaced with Li and Lithium substitution for Zinc as a acceptor is formed. If the content of Lithium increases further, Lithium interstitial is formed again with the redundant Lithium. Therefore, the concentrations of intrinsic point defects of Zinc interstitial and oxygen vacancy varies with the content of Lithium, which leads to the increase of Schottky barrier at grainboundary with Lithium. © (2014) Trans Tech Publications, Switzerland.