Time filter

Source Type

Shi J.,Harbin Institute of Technology | Liu X.,Harbin Institute of Technology | He L.,University of California at Los Angeles | Han M.,Harbin Institute of Technology | And 2 more authors.
IEEE Transactions on Signal Processing | Year: 2016

The linear canonical transform (LCT), which generalizes many classical transforms, has been shown to be a powerful tool for signal processing and optics. Sampling theory of the LCT for bandlimited signals has blossomed in recent years. However, in practice signals are never perfectly bandlimited, and in many cases measurement devices are nonideal. The objective of this paper is to develop a sampling theorem for the LCT from general measurements, which can provide a suitable and realistic model of sampling and approximation for real-world applications. We first describe a general class of approximation spaces for the LCT and provide a full characterization of their basis functions. Then, we propose a generalized sampling theorem for arbitrary measurement and approximation spaces associated with the LCT. Several properties of the proposed sampling theorem are also discussed. Furthermore, the approximation error is estimated. Finally, numerical results and several applications of the derived results are presented. © 1991-2012 IEEE.


Lu F.,Harbin Institute of Technology | Yu J.,Harbin Institute of Technology | Li Y.,Heilongjiang Electric Power Company | Gao H.,Harbin Electrical Power Bureau
Dianwang Jishu/Power System Technology | Year: 2012

To control the transient stability emergency effectively, starting with the information of critical generator pairs a generator tripping/load shedding control strategy based on sensitivity of stability indices of critical generator pairs is proposed. Firstly, the expression of the sensitivity of stability indices of critical generator pairs to control variables is derived and applied to construct constraints of transient stability, and then by means of optimization algorithm the amounts of both tripped generators and shed load needed for emergency control as well as corresponding substations to perform the measures are achieved. Only part of generator information is needed for the proposed method, so the calculation is simple and by means of the sensitivity of stability indices of critical generator pairs the control ability of control quantity to each instable generator can be expressed and its physical meaning is clearer. Simulation results show that the amount of generator tripping and load shedding by the proposed method is less than that by the method based on the sensitivity of margin sensitivity of the whole system.


Jicheng D.,China Electric Power Research Institute | Yongning C.,China Electric Power Research Institute | Lin Z.,Heilongjiang Electric Power Company | Sandholt K.,Ea Energy Analyses | And 3 more authors.
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2011

In recent years, there has been a dramatically development of Chinese wind power, and the scale of the wind farms are increasing. Wind power is a fluctuating energy source, which means that the other power generation units have to adjust to accommodate the fluctuations and ensure the power balance in the grid. This poses the question of how to optimize the power grid to accommodate the increased amount of fluctuating energy. This paper analyses the power system's capability to accommodate wind energy while ensuring the power balance in the system, considering how to achieve the lowest system cost and different constraints such as electricity balance equation, unit minimum load level, unit start-up time etc. The Heilongjiang power system has been chosen as a case study and three scenarios have been analyzed. © Sila Science.


Yan L.,Heilongjiang Bayi Agricultural University | Yan L.,Nanjing Agricultural University | Shao Q.,Heilongjiang Bayi Agricultural University | Wu X.,Heilongjiang Electric Power Company | And 3 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2016

The lactation period is a critical period for sows to breed their piglets, and the specific voice of lactating sows in this period is the most direct expression of their physiology, emotional health, and maternal ability to care for piglets. The rapid location and accurate identification will be more complex due to a variety of vocalizations during this period. Therefore, the vocalizations of nursing grunt, drinking, feeding and sham chewing were observed, and a fine energy calculation for frequency domain with a power ratio as a vector was carried out. Then, the sub-band clustering method based on skewness was presented to merge the sub bands without significant characteristics to reduce the number of parameters. Thirdly, the recognizer for sow's vocalizations was built based on support vector machine(SVM) to calculate the duration of the different types of vocalization. A sound mode of successful nursing was established further within single lactation circle. It is shown that the max power ratio frequency domain of the nursing grunt, the sham chawing, the feeding and the drinking are ranged from 0 Hz to 1 000 Hz, 1 000 Hz to 1 500 Hz, 1 500 Hz to 2 500 Hz, and 2 500 Hz to 8 000 Hz, respectively. The accuracy of the vocalization recognition mode with these four sub bands power ratio frequency as parameters were 100%, 100%, 95.17% and 96.61%, respectively. Compared with the uniformly-spaced sub-band division and principal component analysis (PCA), the number of features was reduced, and the recognition accuracy was significantly improved in the clustering algorithm based on skewness. Thus, the proposed method could be further applied in the health and maternal ability of sows monitoring real-timely and nonstressly. © 2016, Chinese Society of Agricultural Machinery. All right reserved.


Tao X.,Northeast Forestry University | Li Z.,Harbin Engineering University | Liu F.,Heilongjiang Electric Power Company | Zhang Y.,Harbin Engineering University
Gaodianya Jishu/High Voltage Engineering | Year: 2016

In order to solve the imbalance problem that transformer fault samples are not easy to collect, we put forward a novel unbalanced SVM algorithm based on the reduced vector set up-sampling algorithm. Firstly, the GARCH model parameters were used as the power transformer feature vector, then reduced vector set algorithm was utilized to sample up the border samples in the minor samples. The generated artificial minor samples were combined with original minor samples to balance the training samples. The results of the proposed algorithm compared with other sampling algorithms show that the detection rate improves by 6%~9% under different fault samples and different unbalanced datasets. And the generated artificial sample by such algorithm not only can represent the whole structure information, but also includes the local structure information of different combination samples. Therefore, the proposed method can improve fault detection performance of SVM under unbalanced datasets effectively. © 2016, High Voltage Engineering Editorial Department of CEPRI. All right reserved.


Wang L.,Kochi University of Technology | Watanabe T.,Kochi University of Technology | Xu Z.,Heilongjiang Electric Power Company
Energies | Year: 2015

In this study, the structures of external costs are built in line with coal-fired and biomass power plant life cycle activities in Northeast China. The external cost of coal-fired and biomass power plants was compared, using the lifecycle approach. In addition, the external costs of a biomass power plant are calculated for each stage for comparison with those of a coal-fired power plant. The results highlight that the external costs of a coal-fired plant are 0.072 US $/kWh, which are much higher than that of a biomass power plant, 0.00012 US$/kWh. The external cost of coal-fired power generation is as much as 90% of the current price of electricity generated by coal, while the external cost of a biomass power plant is 1/1000 of the current price of electricity generated by biomass. In addition, for a biomass power plant, the external cost associated with SO2, NOX, and PM2.5 are particularly lower than those of a coal-fired power plant. The prospect of establishing precise estimations for external cost mechanisms and sustainable energy policies is discussed to show a possible direction for future energy schemes in China. The paper has significant value for supporting the biomass power industry and taxing or regulating coal-fired power industry to optimize the energy structure in China. © 2015 by the authors.


Tao X.-M.,Harbin Engineering University | Liu F.-R.,Heilongjiang Electric Power Company | Liu Y.,Harbin Engineering University | Tong Z.-J.,Harbin Engineering University
Ruan Jian Xue Bao/Journal of Software | Year: 2012

To deal with the problem of premature convergence and low precision of the traditional particle swarm optimization algorithm, a particle swarm optimization (PSO) algorithm based on multi-scale cooperative mutation, is proposed, which is guaranteed to converge to the global optimal solution with probability one. The special multi-scale Gaussian mutation operators are introduced to make the particles explore the search space more efficiently. The large-scale mutation operators can be utilized to quickly locate the global optimal space during early evolution. The small-scale mutation operators, which are gradually reduced according to the change of the fitness value can implement the accuracy of the solution at the late evolution. The proposed method is applied to six typical complex function optimization problems, and the comparison of the performance of the proposed method with other PSO algorithms is experimented. The results show that the proposed method can effectively speed up the convergence and improve the stability. © 2012 ISCAS.


Lu Z.,Yanshan University | Zhang J.,Yanshan University | Cheng H.,Yanshan University | Bao F.,Heilongjiang Electric Power Company
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

In traditional distributed state estimation, a subarea does not consider the network model and operating state of its neighboring subnet when making its own estimation independently while making up for the previously neglected information only during coordination. To remedy such a situation, a new distributed state estimation based on decomposition and coordination equivalent to external network concentration is presented according to the multi-agent theory. The large-scale power system is decomposed into a number of overlapping subsystems to build a 2-dimensional federated multi-agent framework suitable for distributed state estimation. By establishing the external network concentration equivalent model all subsystems are enabled to consider their neighbors' influence. Thus the estimate solution in each subarea can satisfy definite precision requirements even without outside coordination. A heuristic coordination and correction mechanism based on the blackboard model is founded and the information fusion rate accelerated. And the adjacent systems are subjected to the effect from non-boundary nodes. In addition, outer iteration is performed according to the analysis of the injected power's sensitivity by the quantity of the node states to avoid repeated estimate. Test results on IEEE 14-bus, 30-bus and 118-bus system each show the correctness and effectiveness of the algorithm proposed.


Liang Y.,Harbin University of Science and Technology | Bian X.,Harbin University of Science and Technology | Yu H.,Harbin University of Science and Technology | Liu X.,Heilongjiang Electric Power Company | Li C.,Heilongjiang Electric Power Company
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

The deficient transposition is the widely used type of transposition in stator windings of electric machines. The calculation of circulation current losses in stator winding is very important in the design of stator winding, which will determine the transposition angle of stator windings. The existing leakage susceptible electric potential method, which is used in the calculation of circulation current losses, is only suitable for the electric machines whose one layer winding is composed of one bar. The improved leakage susceptible electric potential method was presented in this paper to calculate the circulation current losses in stator windings of deficient transposition when one layer winding was composed of multiple bars. The circulating current and circulating current losses in the stator winding strands of pump motor used in nuclear power under no-load operation condition were calculated depending on the improved leakage susceptible electric potential method. Compared with the experimental data, the calculation method is proved right. Finally, the distribution of circulating current and circulating current losses in the upper winding strands were obtained when different transposition angles were applied in stator bars and the best transposition angle was determined. © 2013 Chin. Soc. for Elec. Eng.


Zhang H.W.,Heilongjiang Electric Power Company
Advanced Materials Research | Year: 2013

Monitoring system uses upper and lower machine model. The machine adopts the simple operation, reliable performance of PLC acquisition of main fan for each parameter and alarm control. In order to ensure that the fan monitoring system reliability and real time nature, based on the VC++ and SQL Server to develop a set of computer monitoring system. Monitoring software system and data acquisition and processing hardware system connected by a RS-485 bus system. Computer to other computers in a network or through the monitoring host forwarding see fan monitoring interface. © (2013) Trans Tech Publications, Switzerland.

Loading Heilongjiang Electric Power Company collaborators
Loading Heilongjiang Electric Power Company collaborators