Wang W.,Zhejiang Electrical Power Test and Research Institute |
He W.,Zhejiang Electrical Power Test and Research Institute |
Lu K.,Wenzhou Electrical Power Bureau of Zhejiang Province |
Yuan S.,China Electrical Research Institute |
And 3 more authors.
Gaoya Dianqi/High Voltage Apparatus | Year: 2014
To validate the effectiveness of different on-line monitoring devices for power transformers, a state emulation platform was constructed. The architecture and working principle of the platform are described, and the methods for realizing gas configuration, oil heating, partial discharge, and core grounding current are given. Then different on-line monitoring devices for transformer were fixed on the state emulation platform to test their reliability. Experiments demonstrate that this platform can emulate the state quantities of a transformer for validity check of the on-line monitoring devices. ©, 2014, Xi'an High Voltage Apparatus Research Institute. All right reserved.
Teng W.,Xi'an Jiaotong University |
Wang X.,Xi'an Jiaotong University |
Meng Y.,Xi'an Jiaotong University |
Shi W.,China Electrical Research Institute
Journal of Renewable and Sustainable Energy | Year: 2015
With the increasingly high penetration of wind energy, the dynamic influence of wind farms (WFs) on operation security of power systems gains much more attention. Consisting of hundreds of wind turbines (WTs), dynamic analysis on a detailed model of WFs is complicated and time consuming. In this paper, a simplified dynamic equivalent model of WFs based on the spanning tree (ST) is proposed. First, the clustering method based on the growing ST is first applied to the dynamic equivalent of WFs. Second, according to the mathematical model of doubly fed induction generator (DFIG) and permanent magnetic synchronous generator (PMSG), clustering variables of DFIG and PMSG are classified into internal variables and external variables, reflecting the dynamic characteristics of WTs. Finally, based on the actual WFs and actual wind speed data, simulations were employed in DIGSILENT/PowerFactory. The results demonstrate that the proposed model is able to precisely reflect the dynamic characteristics of WFs in both fault condition and fluctuation of wind speed. With time reducing, the effectiveness and feasibility of the proposed model has been verified. © 2015 AIP Publishing LLC.
Chen S.,China Electrical Research Institute |
Wang C.,Northeast Dianli University |
Shen H.,China Electrical Research Institute |
Gao N.,North China Electrical Power University |
And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012
The running states of wind generators are not identical due to the influence of some factors (such as wake effect). In order to improve the precision of the wind farm model for the actual operation, a dynamic equivalence modeling method that is suitable for doubly-fed wind generators was proposed. The state variables of matrix of the wind generators were adopted as cluster-dependent index. By using clustering algorithms, the data of matrix were divided into groups and the wind turbine generators in the same group were equivalent as a wind generator, therefore, the dynamic equivalence of the wind farm was realized. The faults at power system side and the change of wind velocity were simulated on PSD/BPA power system analysis platform and the results were compared to that of the traditional method. The simulation results show that it is reasonable that the state variables of simulation process were considered as cluster-dependent index. The dynamic characteristic of the new model is the same to that of the detailed model and it can be applied to describe the actual states of a wind farm. © 2012 Chinese Society for Electrical Engineering.
Zhou Q.,Chongqing University |
He W.,Chongqing University |
Li S.,Chongqing Electric Power Company |
Hou X.,Chongqing Electric Power Company |
Li D.,China Electrical Research Institute
Gaodianya Jishu/High Voltage Engineering | Year: 2016
In the power system, the traditional voltage transformer has a large size and a high level of insulation. In view of the above questions, we researched a new non-contact voltage transformer, which could reduce difficulty in voltage transformer insulation design and expand the application of voltage transformer. On the basis of the electric field coupling principle, we designed a new voltage transformer. The design of unipolar structure has solved problems of traditional voltage transformer such as great difficulty in insulation design and high cost caused by grounding electrode. Differential signal input structure is adopted for the detection circuit, which has effectively restrained the influence of common-mode interference signal. The voltage transformer is applied to the single-phasevoltage class of 10 kV for test. According to the test results, the designed transformer can meet the requirements of accurate and real-time measurement for voltage of the charged conductor as well as provide a new method for electricity larceny prevention and on-line monitoring of power grid in electric system. © 2016, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
Cai,Northeast Dianli University |
Shi Y.,Northeast Dianli University |
Guo X.,China Electrical Research Institute |
Han Y.,China Electrical Research Institute |
Yang D.,Northeast Dianli University
Dianwang Jishu/Power System Technology | Year: 2016
When multiple DC links are connected to the same receiving-end system, dense DC dropping locations bring a challenge to power grid operation. It is important to arrange the locations reasonably for safe and stable operation of power grid. Based on multi-infeed interaction factor, this paper defined coupling distance between different nodes and divided receiving-end system into several sub-systems by clustering. The clustering result showed that interaction between nodes from the same sub-system was strong and interaction between nodes from different sub-systems was weak. Each DC took one sub-system as its alternative dropping area and all possible schemes constituted a scheme set. Then multi-infeed short circuit ratio was taken as objective and comprehensive variable weight method was used to evaluate dropping schemes. At last, compared with existing screening method for the same case, analysis shows that the proposed method in the paper is reasonable and simple, and can be applied in DC location planning. © 2016, Power System Technology Press. All right reserved.
Yi J.,China Electrical Research Institute |
Tu J.,China Electrical Research Institute |
Xu S.,China Electrical Research Institute |
Lin W.,China Electrical Research Institute |
And 2 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015
Power impacts may lead to power fluctuation on the tie-line of two-area interconnected power systems. If the fluctuation amplitude is large enough, the stability of power system may be threatened. In this paper, the AC tie-line power fluctuation of two-area interconnected power systems was represented as the time domain response of a two-order linear system. Moreover, based on the power system three-stage power allocation theory after power impacts, the periodic variation rule of AC tie-line power fluctuation of two-area interconnected power systems after repeated power impacts was analyzed, the variation mechanism was clarified, and the calculation procedure of power fluctuation peak value in each period was proposed. The effectiveness of the theoretical method were verified by the measured data of one practical repeated power impact incident of the North China-Central China interconnected power system in 2015. © 2015 Chin. Soc. for Elec. Eng.
Tian X.,China Electrical Research Institute |
Han Z.,China Electrical Research Institute |
Li F.,China Electrical Research Institute |
Gao F.,China Electrical Research Institute |
Zhu Z.,China Electrical Research Institute
Proceedings - International Conference on Computer Distributed Control and Intelligent Environmental Monitoring, CDCIEM 2011 | Year: 2011
According to the structure of thermalpower plant unit, and combining the dynamic relationship between the various parameters, a parameter estimation technique in vacuum state for mathematical model of the boiler-turbine units is proposed, which based on the modern control theory andprevious research results. At the same time we try to give an analysis method ofthe mathematicalmodel withequilibrium points inthis paper, at last the reliability and applicability of the method is proved through a practical example. © 2011 IEEE.
Li Z.-X.,China Electrical Research Institute |
Li G.-F.,China Electrical Research Institute |
Fan J.-B.,China Electrical Research Institute |
Yin Y.,China Electrical Research Institute
Applied Computational Electromagnetics Society Journal | Year: 2011
In order to improve the precision of the numerical result, the fast convergent Galerkin's type of boundary element method (BEM) with one order basis function is developed to calculate the grounding system buried in the vertical multilayer earth model. In this paper, the method is taken to simulate and analyze a grounding system including a floating electrode with any complicated structure, which can be located anywhere in the vertical multilayer earth model. The quasi-static complex image method (QSCIM) and the closed form of Green's function for the vertical multilayer earth model are introduced; the QSCIM is implemented by the matrix pencil (MP) approach. © 2011 ACES.