There exists a fatal disadvantage for the integrated induction motor load model of too many parameters, which leads to the difficulty of finding optimal parameters set in the identification process. For this reason, a...
详细信息
There exists a fatal disadvantage for the integrated induction motor load model of too many parameters, which leads to the difficulty of finding optimal parameters set in the identification process. For this reason, a model parameter reduction method is proposed in this paper, which divides the above 14 parameters into two parts: one fixed parameters part alpha F and the other part alpha C : parameters needing identification. After defining of the representability of the load model, the criterion of rational division of alpha F and alpha C is set as remaining the representability of the load model. Thus the strategy of parameter reduction belongs to the optimization methods. For avoiding the large scale optimizing process, the reduction method of building priority sequence based on parameters' sensitivity is proposed. In the end, a case study is given out on the basis of certain power grid measurement data, which verified the simplicity and effectiveness of the proposed method
A 2-step tariff mechanism is adopted in Chinese electric power market. That means the payment of the customers is calculated through the cosPhi of a net node. So the value of cosPhi is used to adjust the rate of consu...
详细信息
ISBN:
(纸本)9810557027
A 2-step tariff mechanism is adopted in Chinese electric power market. That means the payment of the customers is calculated through the cosPhi of a net node. So the value of cosPhi is used to adjust the rate of consumer's tariff. But because of the policy, the value of the adjusted rate can't be calculated accurately in advance. Some problems always lie in how to choose a proper model to make sure the adjusted value of electric rate when to analyze the economic benefit. The paper firstly points out the disadvantage of traditional method on forecasting the adjusted rate through cosPhi. Then it presents a new method to establish the forecast model based on regressive analysis. The model proposed here was applied in a distribution company and given the reasonable result. The paper describes the applicability of the proposed model and gives some explanation for application
Through the analysis on voltage source converter (VSC) equations in dq0 coordinate system, the state space equation of the generalized plant is gained. By use of H infin theory, constant DC voltage H infin controlle...
详细信息
Through the analysis on voltage source converter (VSC) equations in dq0 coordinate system, the state space equation of the generalized plant is gained. By use of H infin theory, constant DC voltage H infin controller and constant AC voltage controller are designed. On the basis of establishing MATLAB simulation model for transmitting power to passive network via VSC-HVDC system, the simulation of control modes, such as constant DC voltage control, constant AC voltage control and constant reactive powercontrol, is conducted. Simulation results show that the proposed controller can meet the need of supplying power to passive network and the control modes are effective
Short-term load forecasting of powersystem is not only the basis of scheduling of generating sets, but also the basis of working out the transaction schedule in electricity market. This paper proposes a short-term lo...
详细信息
A new ultra high-speed protection scheme is proposed in this paper. Using wavelet transform with multiresolution analysis, the current signals is decomposed into a series of detailed wavelet components. The spectral e...
详细信息
ISBN:
(纸本)9810544693
A new ultra high-speed protection scheme is proposed in this paper. Using wavelet transform with multiresolution analysis, the current signals is decomposed into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to detect the faults. Characteristics of the proposed ultra high-speed protection algorithm are analyzed and results of simulation studies are given. The results show that the proposed algorithm is promising and easy to implement for computer relaying application.
A new method, which integrates the virtue of the probability and mathematical statistics with that of the fuzzy mathematics for power quality assessment, is proposed in this paper. The index showing an aspect of power...
详细信息
A new method, which integrates the virtue of the probability and mathematical statistics with that of the fuzzy mathematics for power quality assessment, is proposed in this paper. The index showing an aspect of power quality is evaluated using probability and mathematical statistics respectively; the global unique index of these indexes can be obtained. The results obtained from each index unified are unified again using fuzzy synthetic appraisal in order to give an objective, overall and unique index of power quality. The special assessment method for voltage sag using the average sag energy index is also discussed. Finally, a transaction mode makes the maximum benefits for different unit commitment as objective function and takes the power quality into account is presented, and then power energy really becomes a commodity which would be evaluated a price according to power quality
Voltage source converter (VSC) based HVDC (VSC-HVDC) technology is a kind of newly developed HVDC transmission technology. Based on analyzing the fundamental functions of VSC-HVDC, a dynamic mathematic model based on ...
详细信息
Voltage source converter (VSC) based HVDC (VSC-HVDC) technology is a kind of newly developed HVDC transmission technology. Based on analyzing the fundamental functions of VSC-HVDC, a dynamic mathematic model based on energy conservation principle is developed in this paper. The process of energy conversion and dynamic operation mechanism are analyzed. Theoretical analysis and the controlsystem are validated by simulation on software PSCAD/EMTDC
With increasing attention to sustainable development and environmental protection, more and more countries turn to wind energy to reduce their dependence on traditional fossil fuel energy. Among the new challenges wit...
详细信息
With increasing attention to sustainable development and environmental protection, more and more countries turn to wind energy to reduce their dependence on traditional fossil fuel energy. Among the new challenges with this trend is how to integrate wind farm with existing AC network more effectively. The paper presents a possible measure based on VSC-HVDC, namely so-called wind farm incorporated VSC-HVDC (WVSC-HVDC). In the paper the wind farm along with an AC grid supplies to a passive network. The paper firstly introduces VSC-HVDC, and then presents a space vector based control strategy for supplying to a passive network. The rectifier controls DC voltage and reactive power that is needed by the wind farm. The inverter controls the AC bus voltage in the passive network. Simulations using PSCAD/EMTDC are performed to study the steady and transient behaviors of WVSC-HVDC. With harmonics analysis, the simulation results will be helpful for further understanding of the operation characteristics of WVSC-HVDC and its protection design
Condition-based maintenance is an advanced maintenance strategy which is based on the monitoring of equipments status and according to the results of monitoring and analysis people can arrange maintenance scientifical...
详细信息
Condition-based maintenance is an advanced maintenance strategy which is based on the monitoring of equipments status and according to the results of monitoring and analysis people can arrange maintenance scientifically. When monitoring and analyzing the status of equipments, there are vast historical and on-line data to analyze. If we can find the main factors leading to equipment failure through analyzing the data and pay more attention to these factors, we can make maintenance decision more exactly and quickly. In this paper we propose to apply ID3 algorithm to classify the data according to the importance of their influence to equipment failure and then find the factors which influence equipments most. After finding the most important factors, apply Monte Carlo simulation to forecast the probability of equipment failure which occurs in their operational life span, and according to this we can pay more attention to monitor the factors which result in failure easily
A new data-mining method for assessment of the ability of bidding units is proposed in this paper. The algorithm of reducing attribute value is introduced to get minimum rules. An example which considers the various f...
详细信息
A new data-mining method for assessment of the ability of bidding units is proposed in this paper. The algorithm of reducing attribute value is introduced to get minimum rules. An example which considers the various factors is illustrated the procedure of finding association among many factors and then obtained the rules to assess bidding units ability. The rules are very useful in supporting the generating bidding unit to make decisions and helping the electric agency (power exchange-PX) and (independent system operator-ISO) to design an optimal trade plans
暂无评论