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Shanghai, China

Zhang Y.,East China Grid Company | Yan C.,China Haisum Engineering Co. | Xie Q.,Tongji University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

The current design code requests that wind actions should be considered in the design of icing transmission tower. Taking 1000 kV double circuit transmission lines of an ultra high voltage (UHV) transmission project as the prototype, a large wind tunnel test on icing aeroelastic model was carried out to find out the dynamic interaction of wind-induced vibration for icing transmission tower-line coupling system. The aerodynamic characteristics of the transmission tower-line system were simulated and the boundary conditions were simulated by the equivalent towers. The vibration response of acceleration and displacement were observed in the test. Compared with its counterpart without icing, it was found that the damping ratio in the icing system increased a lot. The dynamic strains of the eight-bundled conductors were measured by using fiber Bragg grating (FBG). The dynamic property variation of the icing conductor and its impact on the transmission tower under the wind load were investigated. The results show that the reasonable dynamic interaction under turbulence flow in the icing tower-line coupling system should be taken into account. © 2010 Chin. Soc. for Elec. Eng.

Wu D.,Zhejiang University | Wang Y.,Zhejiang University | Guo C.,Zhejiang University | Liu Y.,East China Grid Company | Gao Z.,Yantai Power Supply Bureau
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

An economic dispatching model of the power system considering wind power forecast error in the electricity market environment is developed. For a certain wind power forecast value, a Beta function is used to fit the probability density distribution of the real-time available output power. Considering the probability of the forecast error and the economic compensation cost they caused, a more reasonable dispatching model in statistics is proposed. The model is based on the more sound electricity market environment, and the cost of greenhouse gas emission right that needs to be considered by the power company is taken into account. A simulation case compares the effects of the wind power forecast errors on the market clearing price and average purchasing cost of the power grid. The result shows that the proposed model can effectively reduce the operating cost of the power company, and promote the optimal allocation of resources. © 2012 State Grid Electric Power Research Institute Press.

Wang D.,East China Grid Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

As a spin-off from the paper "Comparison of CPS and Its Assessment Between North America and China", some academic discussions are held about frequency checking and control performance assessment periods, frequency checking method, methods of improving the CPS1 value, and drawing of conclusions. Meanwhile, it is pointed out that when making an adjustment of the frequency control method, investigations should carefully be made by referring to the actual conditions of China's power grids prior to circumspect modification.

Jiang Q.,Zhejiang University | Zhou B.,Zhejiang University | Zhang M.,East China Grid Company
IEEE Transactions on Power Systems | Year: 2013

This paper presents a transient stability constrained unit commitment (TSCUC) model which achieves the objective of maintaining both transient stability and economical operation. In the TSCUC model, transient stability constraints are incorporated into the framework of unit commitment. In order to solve TSCUC problem, augmented Lagrangian relaxation (ALR) combined with variable duplication techniques and the auxiliary problem principle (APP) is used to decompose the TSCUC problem into two sub-problems: one sub-problem is a traditional unit commitment (UC) problem with prevailing constraints; another sub-problem is modeled as a transient stability constrained optimal power flow (TSCOPF) problem. The first sub-problem is solved by dynamic programming, while the second sub-problem is solved using a reduced-space interior point method. In ALR, an efficient hybrid sub-gradient method is developed to update all Lagrangian multipliers. The iterative process continues until the duality gap is sufficiently small. Finally, case studies show that the proposed methodology is very efficient for solving TSCUC problems within a parallel computing framework. © 2012 IEEE.

Liu L.,Shanghai JiaoTong University | Cheng H.,Shanghai JiaoTong University | Ma Z.,East China Grid Company | Yao L.,China Electric Power Research Institute | Bazargan M.,Alstom
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

In order to overcome the defect that the applications of life cycle cost (LCC) technology are limited to specific equipment or phase, a three dimensional LCC hierarchy model for entire transmission network was established, which includes time dimension, component dimension and cost dimension. The cost dimension was further divided into device layer, system layer and the cost of externalities. The impact of the reliability centered maintenance (RCM) strategy on the maintenance cost was analyzed. The expected energy not supply (EENS) was used to calculate failure cost. On this basis, four uncertainties such as wind power were simulated, and then the multi-objective chance-constrained transmission expansion planning model was proposed with minimum LCC and minimum load cut. The normal boundary intersection (NBI) algorithm integrated with improved niche genetic method was adopted to solve the model effectively. Finally, case studies were carried out respectively on an 18-bus system and 77-bus system. The results generate distributed Pareto set and recommend the optimal planning scheme. Additionally, the distribution structure of LCC shows the proportion and influence of each cost and can instruct the asset management of power systems in the future. © 2012 Chin. Soc. for Elec. Eng.

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