It is necessary to acquire the relationship between the turbine power output and condenser pressure under the certain steam load since the condenser pressure has a great influence on the turbine power *** paper first ...
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It is necessary to acquire the relationship between the turbine power output and condenser pressure under the certain steam load since the condenser pressure has a great influence on the turbine power *** paper first analyzes the varying parameters of the regenerative extraction cycle system caused by condenser pressure adjustment,and then sets up their calculating models through mechanism analysis and formula *** this basis,this paper attains the change of turbine power output caused by condenser pressure adjustment through the power expression.
Modern powersystem is a hybrid powersystem, which contains renewable power plants. In those power plants, wind farm has shown the world's fastest rate of growth. The reported researches about decentralized coord...
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ISBN:
(纸本)9781479947249
Modern powersystem is a hybrid powersystem, which contains renewable power plants. In those power plants, wind farm has shown the world's fastest rate of growth. The reported researches about decentralized coordinated control of powersystem are all based on synchronous generator(SG). It is not suitable that applying this decentralized-coordinated method to a hybrid powersystem for that the wind-generated energy capacity has been reached a considerable level. Combining correlative measurement modeling and multiple model predictive control, this paper proposes a decentralized coordinated multiple model predictive control(DCM-MPC) for a hybrid wind-thermal power(HWP) system. The transient problems of wind power integration are discussed subsequently. A simple, generic HWP system is used to illustrate the contributions. The results show that the proposed DCM-MPC not only provides an accurate tracking performance, but also improves transient stability of the HWP.
This paper deals with nonlinear model based adaptive power capture control of wind energy conversion systems (WECS) using online approximator (OLA) in low-speed region. Compared with the traditional linear techniques ...
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This paper deals with nonlinear model based adaptive power capture control of wind energy conversion systems (WECS) using online approximator (OLA) in low-speed region. Compared with the traditional linear techniques valid only around an operating point, which may result in poor system performance and low reliability since the operating point may change with time due to the stochastic operating conditions, the developed controller in this paper is totally a nonlinear one capable of covering the whole operating range. In addition, with the aid of a two-layer neural network, we waive the requirement of system dynamics and aerodynamic torque. Furthermore, the weights of neural network are updated in an online manner, which means that no off-line training is needed. Finally, the effectiveness and merits of our proposed controller are verified on a 1.5 MW three-blade wind turbine using the FAST (Fatigue, Aerodynamics, Structures, and Turbulence) code developed by the National Renewable Energy laboratory (NREL).
Nowadays, the network mode of the most energy recovery power battery testing instruments adopts AC-microgrid, which has the drawbacks of low energy recovery efficiency, complicated power circuit topology, cumbersome o...
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In this paper a coordinated control strategy of air-conditioning load groups is proposed to help correct imbalances between load and generation, especially when the powersystem is under stressed conditions such as th...
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In this paper a coordinated control strategy of air-conditioning load groups is proposed to help correct imbalances between load and generation, especially when the powersystem is under stressed conditions such as the loss of power generation. Firstly, a decentralized air-conditioning load group control strategy (control mode 1) is presented accounting for maintenance of load diversity, so that the large oscillations of aggregated power of load group caused by diversity loss can be avoided. However, there is an unwanted parasitic "power peak" in the control mode 1. To eliminate the negative effects of the "power peak", another load control strategy (control mode 2) is borrowed from the literature which requires to communicate with the control center. Both of the control modes 1 and 2 adopt a segmental load recovery scheme to avoid "recovery peak". Then, a coordinated load control strategy is presented to coordinate the control modes 1 and 2. The "power peak" in control mode 1 is used as the powercontrol objective for the load group of the control mode 2, and the control signal for control mode 2 can be calculated using the dichotomy method. simulation results verify the effectiveness of the proposed coordinated control strategy of air-conditioning loads for powersystem balancing.
In this paper, the impact of stochastic time delay on wide-area damping networked controlsystems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model o...
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ISBN:
(纸本)9781467355339
In this paper, the impact of stochastic time delay on wide-area damping networked controlsystems is analyzed. A disintegrate method of time-delay upon sampling period is approved. Furthermore, the expectative model of networked controlsystems with long and stochastic time delay, whose variance extent is larger than one sampling period, is theoretically proved and calculated. Finally, the effectiveness of this expectative model is confirmed on the simulation of a powersystem with 8 generators and 36 nodes.
This paper deals with the finite-time stability and stabilization for continuous-time linear stochastic time-varying systems. Several necessary and sufficient conditions and a sufficient condition for finite-time stab...
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This paper studies the robust consensus problem for second-order multi-agent systems with nonuniform time-delays and switching topologies in the presence of external disturbances, where each agent has a self-delay and...
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ISBN:
(纸本)9781479938926
This paper studies the robust consensus problem for second-order multi-agent systems with nonuniform time-delays and switching topologies in the presence of external disturbances, where each agent has a self-delay and each delay is independent of each other. A neighbor-based rule is used for the agents with nonuniform time-delays and external disturbances. A sufficient condition is derived under which all agents achieve consensus while satisfying desired H ∞ performance. Finally, the effectiveness of the obtained theoretical results is demonstrated through numerical simulations.
Limiting short circuit current and increasing powersystem stability is a contradiction. An optimization and decision model for limiting short circuit current considering sensitivity ranking is established. Firstly, t...
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ISBN:
(纸本)9781479950331
Limiting short circuit current and increasing powersystem stability is a contradiction. An optimization and decision model for limiting short circuit current considering sensitivity ranking is established. Firstly, the influence on impedance matrix caused by current limiting measures is analyzed, and a variable selection strategy considering the sensitivity relation between current limiting measures and node self-impedance is proposed. Secondly, the objective functions which minimize the total investment costs and the short circuit capacity margin are presented, and an adaptive hybrid particle swarm optimization algorithm is used to find a scheme set. Finally, a comprehensive evaluation model is established based analytic hierarchy process and the systematic and quantitative assessments are realized by the fuzzy algorithm. simulation results of the practical power grid demonstrated the efficiency and speediness of this proposed model.
This paper presents a new impedance-based fault distance calculation formulation for power distribution systems. The majority of low- or medium- voltage distribution systems are characterized by having numerous branch...
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ISBN:
(纸本)9781479975389
This paper presents a new impedance-based fault distance calculation formulation for power distribution systems. The majority of low- or medium- voltage distribution systems are characterized by having numerous branches, laterals and sub-laterals, highly unbalanced operation, and time varying load profile. All of these and other characteristics make most efficient approaches proposed for fault location in power distribution systems not applicable to distribution systems. The proposed method uses only measurements of voltage and current at the beginning of the analyzed feeder, and additional equipments such as, fault locators and monitoring devices are not needed to be installed in the distribution system. The apparent impedance is calculated by using the fundamental rms values of the measured voltage and current in this paper. This method is suitable to any kinds of fault and can be used to unbalanced power distribution systems, since it is derived in phase domain.
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