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Yang F.,Chongqing University | Cheng P.,Chongqing University | Yang Y.,Chongqing University | Chen J.,Chongqing Power Grid Maintenance Company | Chen T.,Chongqing Electric Power Research Institute
Asia-Pacific Power and Energy Engineering Conference, APPEEC | Year: 2012

To increase the current carrying capacity of the power cable, more and more power tunnel are installed with ventilation. Hence in the paper the heat dissipation of power cable is investigated. Firstly the model to calculate the thermal field of power cable with natural ventilation is presented based on the fluid mechanics and heat transfer, and the governing equations and boundary conditions are inferred. Then the thermal field for six-loop cables in power tunnel was calculated, which verified the accuracy of the model. In addition, the factors influencing the thermal field with ventilation is investigated, including the size of the power tunnel, the distance between the cable. Finally the current carrying capacity of the power cable is calculated and the economic benefit of the operation mode of power cable is analyzed. © 2012 IEEE. Source

Chen M.,Chongqing University | Yu L.,Chongqing University | Wade N.S.,Durham University | Liu X.,Chongqing Nanping Power SupplyBureau | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2011

Different faulty states of a doubly fed induction generator (DFIG) connected to a microgrid are investigated in this paper. First, the simulation model consisting of two DFIGs connected to IEEE 34-bus test feeder for two vector control based was set up to investigate the transient performance of the microgrid. Then, different types of faults of the DFIGs, including partial loss of excitation (PLOE), complete loss of excitation (CLOE), and interturn short circuit (ISC) were analyzed through the simulation model using vector control strategy. The experimental results indicate that the active power will increase during the PLOE, and the average increase of the amplitude is about 26%, which will decrease the electromagnetic torque by 8% and increase the voltage at the neighbor node, the stability of the microgrid will be broken eventually. For the CLOE, the active power decreases about 80%, and node voltage decreases by 9.4% due to the inverse absorption of the reactive power. When the ISC occurs, the average node voltage and the active power decrease together. Finally, the suggestion for the detection of the DFIG faults is presented, which could be helpful to protect the DFIG from fault accident. © 2011 IEEE. Source

Zhao X.-Y.,Chongqing Power Grid Maintenance Company | Cheng J.-B.,Chongqing Power Grid Maintenance Company | Wang X.-Q.,Chongqing Power Grid Maintenance Company | Wang L.,Chongqing Power Grid Maintenance Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2011

This paper researches in depth on how to estimate the immediate support ability of power maintenance company when power grid is in a state of emergency. This has been a perplexed issue for a long term. From the practical perspective, taking the staff, supplies, facilities required and some other factors into consideration, a three-level index system is introduced and the power grid Urgent Guarantee Index (UGI) is established. In the UGI system, Multi-objectives Particle Swarm Optimization (IMOPSO) algorithm is employed to get the optimal solution for the weighting distribution, using the practical maneuver score as objective function. The final weight value of all factors is acquired by the Self-adaptive Weight method. The index (UGI) is the sum of respective scores multiplied by corresponding weight value. Through comparing the index (UGI) with the data obtained in practical maneuver, the UGI system is proven to be practicable and effective. Source

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