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Chen L.,Tsinghua University | Hou K.-Y.,Northeast China Grid Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

The sensitivity of transient stability margin to generator output power plays an important role in transient stability preventive control. An analytical sensitivity of transient energy margin to generator power is derived. The structure preserving model of power systems with constant power active load and constant impedance reactive load is adopted. An analytical formula of the sensitivity of transient energy margin to generator power is derived. There are no other assumptions except the adopted power system model and the assumption that output powers of generators are constant during the fault. The sensitivity is easy to calculate and applicable to power system detailed models. The sensitivities can be used for transient stability preventive control. Simulation results verify the validity of sensitivity and its applicability in transient stability preventive control. Source


Li H.,Northeast Dianli University | Yin L.,Northeast China Grid Company
Proceedings - International Conference on Electrical and Control Engineering, ICECE 2010 | Year: 2010

Increasingly nonlinear dynamic loads have been connected into power systems; such as variable speed drives, robotic factories and power electronics loads. This adds to the complexity of load modeling. The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation and turbine systems. The crucial factors affecting the modern power systems today is voltage control and system stabilization during small and large disturbances. Simulation studies and real-time laboratory experimental studies carried out are described and the results show the successful control of the power system excitation and turbine systems with adaptive and optimal neurocontrol approaches. © 2010 IEEE. Source


Chen L.,Tsinghua University | Min Y.,Tsinghua University | Hou K.,Northeast China Grid Company
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2016

A probabilistic steady-state voltage stability assessment method considering stochastic wind power was proposed. The L index was adopted to assess the voltage stability of buses, and the sensitivity of L index to bus injection power was firstly derived. From the probability density function of wind power, the cumulants were computed, and then the cumulants of L index were computed from the approximate linear relationship of L index and bus injection power. Finally the probability density function of L index was reconstructed using the Gram-Charlier series expansion and used to compute the risk of voltage instability, which could be used to assess the voltage stability of the system and identify weak buses. The method is validated by simulation results and can be used for probabilistic steady-state voltage stability assessment of power systems with wind power integration. © 2016 Chin. Soc. for Elec. Eng.. Source


Li W.-W.,China Three Gorges University | Wu X.-X.,China Three Gorges University | Huang J.,Sanmenxia Power Supply Company | Ma Q.,Fujian Electric Power Company | Guo X.-H.,Northeast China Grid Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2013

Because of the uncertainty of the natural runoff of reservoir, a mid-long term reservoir operation stochastic optimization model is established for the hybrid pumping storage power station based on describing the stochastic process of runoff, which takes the maximum energy generating expectation as its objective. The stochastic dynamic programming algorithm has two control variables: water flow and pumping time. Case study of Baishan mixed pumped storage units shows the energy generating expectation of scheduling period increases from 2 165 million kW·h to 2 463 million kW·h, the guaranteed output increases by 12 MW, and the water level is slightly higher in all periods. At the same time, compared with the model established by the long series of law, the stochastic model obtains better results and the model can better reflect the randomness of the natural runoff, even more practical. Source


Yang S.,Northeast Dianli University | Yin L.,Northeast China Grid Company
ICSESS 2011 - Proceedings: 2011 IEEE 2nd International Conference on Software Engineering and Service Science | Year: 2011

Increasingly nonlinear dynamic loads have been connected into power systems; such as variable speed drives, robotic factories and power electronics loads. This adds to the complexity of load modeling. The increasing complexity of the modern power grid highlights the need for advanced modeling and control techniques for effective control of excitation and turbine systems. The crucial factors affecting the modern power systems today is voltage control and system stabilization during small and large disturbances. Simulation studies and real-time laboratory experimental studies carried out are described and the results show the successful control of the power system excitation and turbine systems with adaptive and optimal neurocontrol approaches. © 2011 IEEE. Source

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