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..
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.
Xu J.,Shenyang University of Technology |
Li J.,Shenyang University of Technology |
Zhang M.,Northeast China Grid Company |
Li B.,Shenyang University of Technology
Dianwang Jishu/Power System Technology | Year: 2012
To improve dynamic characteristics of voltage support for microgrid, based on the concept of multi-agent control a dynamic coordinated control method for voltage support among distributed generations (DG) was proposed. The network characteristics of microgrid was analyzed; the relational model of DG nodes to voltage support adjustment of other nodes was derived; utilizing agent control theory the vector function of voltage support decision-making for agent in executive level was established to perform optimal sequence criterion operation with voltage objective evaluation vectors, and then a coordinated control algorithm was constructed. According to the constructed algorithm, the time-sequences of output compensation of DG agents were judged to form optimal dynamic performance control mode of voltage support to implement fast and stable support for post-fault voltage along with coordinated power compensation among DGs. Typical Finland rural microgrid model was used for digital simulation, and simulation results showed that the proposed method possessed satisfied robustness and adaptability.
Li W.,China Three Gorges University |
Huang J.,China Three Gorges University |
Guo X.,Northeast China Grid Company
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012
A mid-long term optimal reservoir operation model is built for the hybrid pumped storage power station, which takes the maximum mean annual energy generation for multiple years as its objective. The dynamic programming algorithm, which has two control variables: water flow and pumping time, is applied to discretize the long data sequence of water level and pumping time for searching their best combinations for different periods. Case study shows that, with the added pumped storage units, the mean annual energy generation increases from 2063 million kW·h to 2306 million kW·h, the firm power increases about 0.01 million kW, the water level is slightly higher in all periods, and the discretization error is less than 0.4% when the step of discretized pumping time is 1 hour per day.
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.
Su X.,North China Electrical Power University |
Ji C.,North China Electrical Power University |
Huang X.,North China Electrical Power University |
Jia D.,Northeast China Grid Company |
Guo X.,Northeast China Grid Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010
On the premise of taking full account of the Northeast power grids peak regulating demand and the operation of the pumped-storage units, effort is made to optimize Baishan Reservoir dispatching, improve the water level for the Baishan Reservoir to obtain maximal additional generation by the "head", and realize maximal annual power generation or annual load regulation benefits of the cascade power station. The results show that, for the Baishan Hybrid Storage Station, the conversion efficiency of the maximal power generation model is higher than that of the maximal peak load regulation benefit model, the conversion efficiency of the two models being 90.65%~95.50% and 87.94%~92.58%, respectively, both higher than the efficiency of the simplex pumped-storage power station which shows the advantages of the hybrid pumped-storage power station. Although the work of pumped-storage units has little influence on Hongshi Reservoir with just daily regulating capacity, it aggravates the uneven distribution of runoff of Fengman Station with yearly regulation capacity so that the cascade conversion efficiency is only 75.93%~82.62%. This shows that the efficiency of the hybrid pumped-storage power station in cascade reservoirs and the impact on other hydropower stations are related to the layout and development type. © 2010 State Grid Electric Power Research Institute Press.
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.
Nie H.,Northeast Dianli University |
Liu G.,Northeast Dianli University |
Liu X.,Northeast Dianli University |
Wang Y.,Northeast China Grid Company
Energy Procedia | Year: 2011
Short-term load is a variable affected by many factors. It is difficult to forecast accurately with a single model. Taking advantage of the autoregressive integrated moving average (ARIMA) to forecast the linear basic part of load and of the support vector machines (SVMs) to forecast the non-linear sensitive part of load, a method based on hybrid model of ARIMA and SVMs is presented in this paper. It firstly uses ARIMA to forecast the daily load, and then uses SVMs, which is known for the great power to learn and generalize, to correct the deviation of former forecasting. Applying this hybrid model to a large sample prediction, the results show that it achieves the forecasting accuracy and has very good prospective in applications. So it can be used as a new load forecasting method. © 2011 Published by Elsevier B.V.
Huang Y.,Shenyang Ligong University |
Li D.,Northeast China Grid Company |
Gao L.,Northeastern University China
Proceedings of the 2012 24th Chinese Control and Decision Conference, CCDC 2012 | Year: 2012
This paper offers one kind of improved artificial immune algorithm which takes different mutation strategy toward different unit that has various quality. This algorithm conducts self-adapt adjustment between mutation rate and crossover rate in order to achieve balance between search accuracy and search efficiency. This paper conducts DAIA-BPNN short-term power load forecast model based on DAIA algorithm. It uses DAIA algorithm to optimize the weight and threshold of BPNN while overcoming the blindness when selecting the weight and threshold of BPNN. The actual calculation example of the short-term power system load forecast shows that the method presented in this paper has higher forecast accuracy and robustness compared with artificial neural networks and regression analysis model. © 2012 IEEE.
Sun Z.,Northeast China Grid Company |
Sun Y.,Northeast China Grid Company |
Bao B.,Northeast China Grid Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2015
In order to improve the security and stability of power grid, a single-phase reclosing mode is usually adopted in the extra-high voltage (EHV) power system. As there is no non-simultaneous problem after a single-phase of the power line trip-out, the traditional single-phase reclosing logic and its realization method is simple. On January 2, 2011, a permanent fault of 500 kV Yihuan line 1 occurred in the Northeast Power Grid. The single-phase reclosing failed, and the short circuit current failed to break, resulting in breaker body damage. Then the failure protection acted and the bus jumped, expanding the power grid accident. In order to avoid similar accident to happen again, the network model characteristics and fault mechanism are analyzed in depth. A short-circuit current characteristic factor for reflecting the line fault is proposed. The threshold of the short-circuit current characteristic factor is defined, which can identify the existing problems of reclosure in the power network. Finally, the reclosure schemes that should be adopted are studied when the grid structure satisfies the characteristics. The effectiveness of the schemes is verified by the operation test in the actual power grid. © 2015 Automation of Electric Power Systems Press.