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Zha C.-M.,Zhongyuan University of Technology | Wang C.-J.,Zhengzhou University of Light Industry | Wei Y.-B.,Zhengzhou University of Light Industry | Li T.,Nanyang Power Supply Company | Lu G.-H.,XJ Electrical Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

To solve this problem that harmonic grounding system fault line zero sequence admittance levy does not highlight, this paper proposes a new resonant grounding line selection method based on EMD. In this method, each line zero sequence admittance is decomposed with EMD, characteristic component is extracted, and the fault line is selected by comparing the characteristic component symbols of the fault line and non-fault lines. Extensive simulations show that this method is not impacted by the ground fault resistance and the initial angle, and can accurately select the fault line. Source


Xiong J.H.,Beihang University | Xiong J.H.,North China University of Water Conservancy and Electric Power | Xu S.Q.,Nanyang Power Supply Company | Yun C.,Beihang University
Advanced Materials Research | Year: 2011

To measure and control thermal defects of power station, continuous power is provided to the ZigBee wireless temperature sensors by using monocrystalline silicon solar cells and thermoelectric generation modules, which can collect and process the real-time temperatures of high voltage equipments in the station. Simultaneity, the system can solve the problem that overheat faults can not alarm timely when efficiency of solar cell decreases during the continuous rainy days. The remote real-time controlling is realized by using client and server programs of VC + +.NET. The lossless compression and real-time image transmission are implemented through employing the screen grid-division method and the Huffman compression algorithm. All of these provide a technical assurance to the remote controlling of heat vice of high-voltage equipments in multi-stations. © (2011) Trans Tech Publications. Source


Wei Y.-B.,Zhengzhou University of Light Industry | Li T.,Zhengzhou University of Light Industry | Zhang G.-L.,Zhengzhou University of Light Industry | Li P.,Nanyang Power Supply Company | Cui G.-Z.,Zhengzhou University of Light Industry
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

Over-compensation and under-compensation can often be found in the traditional reactive power compensation based on the switching state of capacitor banks, which is limited by the times of switching. In order to solve the problem, the operating principle of the magnetic-valve controllable reactor (MCR) based on the instantaneous reactive power theory is proposed. Based on instantaneous reactive power theory and through coordinate transformation, the real time detection for the reactive current of the MCR is realized. On this basis, the basic control strategy of MCR-based intelligent Static Var Compensator (SVC), and the control strategy for unbalanced system are researched and a method for enhancing the MCR response speed is also given. The validity of the above method is proved by experimental results. Source


Wang J.,Hubei Engineering University | Liu H.,Hubei Engineering University | Chen X.,Nanyang Power Supply Company
Dianwang Jishu/Power System Technology | Year: 2011

It is impossible to implement the furthest optimization of distribution by unilateral network reconfiguration or reactive power optimization, so it is necessary to comprehensively consider the two manners. For this reason, a differential evolution algorithm-based comprehensive optimization algorithm for distribution network is proposed. To unify with the integer encode mode for reactive power optimization, the circle branch integer encode mode with the shortest encoding length is applied to network reconfiguration to simultaneously lead network reconfiguration and reactive power optimization into evolutionary process. Meanwhile, the adaptive mutation and the adjusting strategy of parameter evolution are led into evolution process to ensure that the convergence can be accelerated while the optimal solution is obtained. Finally, the measures to reduce calculation burden is analyzed. Results of calculation example show that the proposed algorithm is effective. Source


Liu R.,Zhengzhou University | Zhao G.-S.,Zhengzhou University | Wang H.,Nanyang Power Supply Company | Guo H.,Yuzhou Power Supply Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

This paper presents a three-phase magnetic valve controlled reactor (MCR) whose capacity can be smoothly adjusted with the change of power system parameters. Its application, structure, the working principle and electromagnetic characteristics in power system are introduced briefly, and it is simulated using Ansoft Maxwell 3D finite element analysis software. Simulation analysis confirms that changing controllable thyristor conduction angle can change the current, which proves the feasibility of a smooth adjustment of capacity of MCR. Source

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