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Xie J.W.,Kunming University of Science and Technology | Bi G.H.,Kunming University of Science and Technology | Chen S.L.,Kunming University of Science and Technology | Zhang J.,CSG EHV Transmission Company
Advanced Materials Research | Year: 2014

The method to discriminate the fault within or beyond the protective zone according to the signals with high frequency detected in protection has problem with low reliability when the resistance of earth fault is high. The transient voltage with low frequency detected in protection can reflect the size of fault intensity approximately, and the transient voltage with high frequency detected in protection in internal fault is bigger than that in external fault when the size of fault intensity is same. The high frequency transient voltage and low frequency transient voltage detected in protection are chosen as inputs and fault section as outputs for training and testing the neural network for fault identification in the UHVDC transmission line, fault section can be identified when input fault characteristic data to the trained model. A variety of transmission line earth fault situation are simulated by PSCAD, and this earth fault section identification method based ANN shows satisfactory performance, even the fault resistance is high. © (2014) Trans Tech Publications, Switzerland. Source


Zhang P.,Dali Bureau | Li H.,CSG EHV Transmission Company
Gaoya Dianqi/High Voltage Apparatus | Year: 2015

A transmission line fault in its unipolar metallic return mode has happened, leading to blocking converter in ±800 kV Puer-Qiaoxiang UHVDC system. This paper analyzes the fault in detail, and points out that the breakdown arrester in the neutral bus is the reason that causes neutral bus differential protection and polar differential protection action. In addition, part of DC protection design is imperfect. The optimization measures for corresponding DC protection are given. Practice has proved that the proposed measures effectively improve the reliability of the HVDC system operation. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved. Source


Chen S.,Kunming University of Science and Technology | Zhang J.,CSG EHV Transmission Company | Liu H.,Kunming University of Science and Technology | Xie J.,Kunming University of Science and Technology | Hou Y.,CSG EHV Transmission Company
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2016

A single-ended current direction transient protection of UHVDC transmission line is put forward. Fault current signal outside the region is obviously different in mutation direction from the one at the opposite side. So the direction where the fault signal comes from can be judged. UHVDC boundary and transmission line have attenuation to fault current. If the fault signal comes from the opposite internal, with HHT the instantaneous frequency of IMF1 is calculated. Then, from the maximum value of instantaneous frequency, whether the fault is from the opposite internal or external fault can be judged. A transient current protection scheme of UHVDC transmission line is given. The simulation results of PSCAD verify the protection scheme. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved. Source


Cao J.,CSG EHV Transmission Company | Chen T.,CSG EHV Transmission Company | Jiang Z.,Wuhan University | Wen X.,Wuhan University | Zhang M.,Beijing Power Equipment Group
2014 17th International Conference on Electrical Machines and Systems, ICEMS 2014 | Year: 2015

As dry-type smoothing reactor is a crucial equipment of high voltage direct current transmission project, temperature monitoring is an effective means of inspecting its stable operation. According to computational fluid dynamics and heat transfer theory, steady state calculation of coupling fluid and thermal field for dry-type smoothing is done in the work. By simplifying the computational model of dry-type smoothing reactor reasonably, finite volume method is employed to solve the fluid and temperature fields of 1/4 circumferential region directly, and the distribution characteristics of the reactor temperature field is obtained. Then the axial and radial temperature distributions of encapsulation are researched separately. Finally, the accuracy of the simulation is verified by comparing the computational values with experimental values, the primary area of monitoring encapsulation temperature is proposed. © 2014 IEEE. Source


Chen T.,CSG EHV Transmission Company | Cao J.,CSG EHV Transmission Company | Zhou G.,Wuhan University | Zhipeng J.,Wuhan University | And 2 more authors.
2014 17th International Conference on Electrical Machines and Systems, ICEMS 2014 | Year: 2015

Based on the basic structure characteristics and site layout of ±800kV dry-type smoothing reactor in a converter station, a 3D electrical field calculation model is established in this paper. With the finite element software, the paper studies the electric field distribution in 1.5m plane over ground and in the longitudinal plane of the reactor, and the electric field values in the surface of main buses and grading rings. From the results, it can be concluded that the maximum electric field strength appears outside surface of the grading ring under the middle bus, and the electric field values are all less than 30kV/m in the area which is more than 10m away from the center of the reactor in 1.5m plane over ground. © 2014 IEEE. Source

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