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Jun Z.,South China University of Technology | Jun Z.,Hong Kong Polytechnic University | Junfeng L.,Hong Kong Polytechnic University | Jie W.,South China University of Technology | And 2 more authors.
Renewable Energy | Year: 2011

This paper presents a multi-agent (MAS) solution to energy management in a distributed hybrid renewable energy generation system. An introduction and analysis of the system, including its constituents, characteristics and excitation mechanism are presented first. Then, validation of the MAS solution demonstrates its feasibility in meeting all the requirements of the system. Five kinds of agents are proposed to present the Energy Management System. Each agent is built as a three layered architecture. A macro MAS is also presented in detail with a framework containing its overall optimisation function based on JADE (Java Agent Development). Discussion about the agents' behaviours and a scenario case study on the MAS and its testing process are included in the paper. It indicates that the MAS is a suitable solution for the energy management of the distributed hybrid renewable energy generation system. © 2010 Elsevier Ltd.

Liu M.,Guangdong Key Laboratory of Clean Energy Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2010

The multi-objective control of micro source is studied for three-phase four-wire system. The phase and magnitude of node voltage are estimated according its real time measurement; the grid-side setting P is regulated by the PI controller according to the real output of micro source; the grid-side reference current is set according to the grid-side setting P and Q, as well as the requirements for unbalance and harmonic compensation; the reference current of micro source is obtained by subtracting the grid-side reference current from load current. The multi-objective control is implemented by a hysteresis control of micro source output current, which follows the reference current quickly. Band pass filter is adopted to remove the high-frequency switching disturbance in node voltage measurements and avoid the time delay of common low pass filter. The control strategy is verified by simulation on Simulink platform.

Liu M.,Guangdong Key Laboratory of Clean Energy Technology | Liu W.,Guangdong University of Technology
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2010

As the frequency is not directly associated with the active power in autonomous micro grid, a distributed control strategy based on nodal voltage regulation is proposed to balance its active and reactive powers. The controllable active sources regulate the nodal voltage through its output of active power to maintain the long term voltage level. The storage source working in voltage regulation pattern maintains the short term voltage level by injecting active power into grid, while the storage source working in voltage source pattern keeps the magnitude and phase of nodal voltage stable and the reactive power balanced. The clean sources output all the energy absorbed. The voltage set point of storage source is inversely proportional to its energy storage level, which is used to realize the distributed control of its charge and discharge. The effectiveness of unit control based on proposed strategy is verified by simulation.

Chen W.,Guangdong Key Laboratory of Clean Energy Technology | Liu M.,Guangdong Key Laboratory of Clean Energy Technology
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2012

Detailed and quasi steady-state models of full-process hybrid dynamic simulation of long-term voltage stability are discussed; over-excitation limiter, armature current limiter and dynamic load are modeled. By comparing the results of quasi steady-state (QSS) and full time-scale (FTS) simulation, it is discovered that system may not keep transient stability and enter long-term process when severe disturbances trigger discrete equipment to act in succession. Furthermore, judgment of discrete equipments action through QSS simulation is inexact, which causes the system trajectory depart from the real trajectory. Combining FTS, QSS and continuation-based quasi steady-state (CQSS) simulation, and switching properly, the whole-process hybrid dynamic simulation method is constructed, which can keep the transients after disturbances and discrete equipments' action. It is switched to QSS simulation only when transient process dies out, and switched to CQSS simulation to improve convergence when system trajectory approaches saddle-node bifurcation point and meets convergent problem. The New England 10-machine 39-bus and IEEE 50-machine 145-bus system are used as test systems to prove the limitation of QSS simulation and the applicability of full-process hybrid dynamic simulation.

Liang Z.,Guangdong Key Laboratory of Clean Energy Technology | Ma X.,Guangdong Key Laboratory of Clean Energy Technology
Waste Management | Year: 2010

The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modeling and accurate prediction of pollutant emissions. In this paper, mathematical modeling methods for both solid and gaseous phases were employed to simulate the operation of a 450t/d MSW-burning incinerator to obtain detailed information on the flow and combustion characteristics in the furnace and to predict the amount of pollutant emissions. The predicted data were compared to on-site measurements of gas temperature, gas composition and SNCR de-NO X system. The major operating conditions considered in this paper were grate speed and oxygen concentration. A suitable grate speed ensures complete waste combustion. The predictions are as follows: volatile release increases with increasing grate speed, and the maximal value is within the range of 700-800kg/m 2h; slow grate speeds result in incomplete combustion of fixed carbon; the gas temperature at slow grate speeds is higher due to adequate oxygenation for fixed carbon combustion, and the deviation reaches 200K; NO X emission decreases, but CO emission and O 2 concentrations increase, and the deviation is 63%, 34% and 35%, respectively. Oxygen-enriched atmospheres promote the destruction of most pollutants due to the high oxygen partial pressure and temperature. The furnace temperature, NO production and CO emission increase as the oxygen concentration increases, and the deviation of furnace exit temperature, NO and CO concentration is 38.26%, 58.43% and 86.67%, respectively. Finally, oxygen concentration is limited to below 35% to prevent excessive CO and NO X emission without compromising plant performance. The current work greatly helps to understand the operating characteristics of large-scale MSW-burning plants. © 2010 Elsevier Ltd.

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