A mixed-integer nonlinear programming model is proposed in this paper for reducing excessive standing phase angle difference (SPA) across open circuit breakers in transmission loop paralleling operation. The model ado...
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ISBN:
(纸本)9781479932559
A mixed-integer nonlinear programming model is proposed in this paper for reducing excessive standing phase angle difference (SPA) across open circuit breakers in transmission loop paralleling operation. The model adopts both the active power generation increment and the load switch as control variables and takes the relative importance of the loads to be restored into account, resulting in fewer rescheduled generators and less adjustment of active power generation. The condition for transmission loop paralleling operation can be reached from two ways of reducing generator adjustment time and optimally restoring load. The method can improve power restoration efficiency, speed up restoration progress, and hence reduce the loss of outage. Simulation results of New England 10-machine 39-bus test system demonstrate the effectiveness of the method.
The hydraulic excavator energy-saving research mainly embodies the following three measures： to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the po...
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The hydraulic excavator energy-saving research mainly embodies the following three measures： to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the power matching of diesel-hydraulic system-actuator. Although the above measures have certain energy-saving effect, but because the hydraulic excavator load changes frequently and fluctuates dramatically, so the diesel engine often works in high-speed and light load condition, and the fuel consumption is higher. Therefore, in order to improve the economy of diesel engine in light load, and reduce the fuel consumption of hydraulic excavator, energy management concept is proposed based on diesel engine cylinder deactivation technology. By comparing the universal characteristic under diesel normal and deactivated cylinder condition, the mechanism that fuel consumption can be reduced significantly by adopting cylinder deactivation technology under part of loads condition can be clarified. The simulation models for hydraulic system and diesel engine are established by using AMESim software, and fuel combustion consumption by using cylinder-deactivation-technology is studied through digital simulation approach. In this way, the zone of cylinder deactivation is specified. The testing system for the excavator with this technology is set up based on simulated results, and the results show that the diesel engine can still work at high efficiency with part of loads after adopting this technology; fuel consumption is dropped down to 11% and 13% under economic and heavy-load mode respectively under the condition of driving requirements. The research provides references to the energy-saving study of the hydraulic excavators.
Aiming at the disadvantage of Monte Carlo simulation method in slow convergence and using a great number of computation resources, this paper, based on analytical approach, builds a quick powersystem operational reli...
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ISBN:
(纸本)9781467328685
Aiming at the disadvantage of Monte Carlo simulation method in slow convergence and using a great number of computation resources, this paper, based on analytical approach, builds a quick powersystem operational reliability analyzing model. From the viewpoint of operation, this model which is based on Markov chain, assumes that equipment failure rate follows exponential distribution. Its core content includes three aspects. Firstly, a convenient criterion, used to divide powersystem operation into three states, and the corresponding state-space transition expression are proposed for engineering application. Secondly, Markov state transition probability matrix is obtained based on powersystem operation historical data (or simulation data sample). Thirdly, based on state transition probability matrix and current operating state of powersystem, state transition probability, steady state probability and the mean time to first failure can be acquired very quickly. Example analysis using RBTS-BUS6 system, testified the Markov property of powersystem state transition and the efficiency of this study.
The re-connection issues between the micro-grid and the distribution grid are discussed in the paper. The power flow in the micro-grid is analyzed based on the characteristic curve of frequency-power. In order to amel...
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In the context of Condition Based Maintenance (CBM), this paper presents a risk-based optimization model for system maintenance scheduling problem. It consists on optimizing availability and cost of the system by bala...
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In the context of Condition Based Maintenance (CBM), this paper presents a risk-based optimization model for system maintenance scheduling problem. It consists on optimizing availability and cost of the system by balancing between system maintenance risk and failure risk. In this paper, system reliability constraint is considered. Reliability of system components is characterized by their failure rate functions. Possible maintenance actions are performed to improve the reliability of the system. Genetic algorithm is used to obtain the sequence of maintenance actions providing desired level of reliability with minimum system risk. Numeral results demonstrate effectiveness of the proposed model.
The design of intelligent multi-parameter real-time monitoring system for the security of coal mine roof is introduced aiming at the status of monitoring system for mine roadway roof safety and supporting. Using advan...
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The design of intelligent multi-parameter real-time monitoring system for the security of coal mine roof is introduced aiming at the status of monitoring system for mine roadway roof safety and supporting. Using advanced field-bus CAN technology and Ethernet fiber transmission technology can not only display the measurement data on-site and alarm, but also transmit the measured data through the monitor network of mine to the main monitoring station on the ground and the remote monitoring center for analysis and processing, so that the monitor in command center on the ground can real-time and remotely monitoring the security status on the roof. The actual application showed that the system had the capability of high communication speed, long transmission distance, anti-electromagnetic interference, reliable transmission, and high real-time. The system can play an active role in early warning to avoid the occurrence of coal mine roof disasters.
Aiming at the disadvantage of Monte Carlo simulation method in slow convergence and using a great number of computation resources, this paper, based on analytical approach, builds a quick powersystem operational reli...
详细信息
Aiming at the disadvantage of Monte Carlo simulation method in slow convergence and using a great number of computation resources, this paper, based on analytical approach, builds a quick powersystem operational reliability analyzing model. From the viewpoint of operation, this model which is based on Markov chain, assumes that equipment failure rate follows exponential distribution. Its core content includes three aspects. Firstly, a convenient criterion, used to divide powersystem operation into three states, and the corresponding state-space transition expression are proposed for engineering application. Secondly, Markov state transition probability matrix is obtained based on powersystem operation historical data (or simulation data sample). Thirdly, based on state transition probability matrix and current operating state of powersystem, state transition probability, steady state probability and the mean time to first failure can be acquired very quickly. Example analysis using RBTS-BUS6 system, testified the Markov property of powersystem state transition and the efficiency of this study.
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