共查询到20条相似文献，搜索用时 31 毫秒
1.
The main means of the voltage-reactive power control of substation are adjusting the taps of load-tap-changing transformer or the reasonable capacity of parallel compensating capacitors according to the operation condition of substation.The "nine-area control strategy" is widely used to adjust voltage in the stated range and reduce the transmission capability of reactive power for power system at present.By analyzing the existent shortages of nine-area control mode for voltage-reactive power,an adjusting voltage calculation method is put forward,input data of which are the real time data of current,voltage and power of the substation.Then operation decision of voltage-reactive power control method of substation is made.By the simulating analysis,predigesting method of upper system is built,based on which an applied real time calculating model and calculating steps is given. 相似文献
2.
Geographic Information System(GIS) is playing more and more important role in information management of power system. The popular GIS platform products include GeoMedia, Arc/Info, MapInfo and MicroStation. The choosing and using of power GIS platform should obey the rule in power system reality. Based on their preponderant application in geographic industry, Arc/Info and MapInfo have been successfully used in power system. The scheme of power GIS platform is put forward in this paper, referenced to the judgement and analysis of these prevailing platform, and the example of "GIS information system in Chongqing YuBei Power Supply Bureau" is given. This example shows the powerful twice developing ability, the profound network topology analysis ability of this method, which could also satisfy the needs of excessive and separate work nodes and parallel operation. All researches showed in this paper demonstrate the method could satisfy the need of power GIS. 相似文献
3.
Direction analysis on Contactless Power Transmission System 总被引：1，自引：0，他引：1
After analysis on the direction relationship betueen primary side and secondary side of existing contactless power transmission system, a random rotatable pick-up is proposed. Two connecting modes of three orthogonal wound coils are studied. Based on analysis and mathematical calculation, instantaneous output voltage and its ratio to the maximal and minimal value when the pick-up rotate in three-dimensional space is given. All the calculation is verified by experiment results. 相似文献
4.
5.
To adapt to the continuous improvement of rural power consumption level in the new rural construction,in particular,with the continuous development of the rural economy,the actual operation of the rural power network has emerged as the high loss of electrical power which leads to a greater cost of the electricity,lower power supply reliability,the supply voltage and frequency do not satisfiy with requirements,etc.Through analysis of a typical rural power network,from the overall planning of the transmission to distribution equipments(such as lines,transformers and reactive-load compensation devices),the author proposes some specific measures such as reducing power loss and improving the voltage quality and reliability methods.Through calculation for lines power loss rate and percent of voltage pass,the results show that the methods proposed by the author are effective.The directions to the development trend of the rural power network is given. 相似文献
6.
This paper discuas the controlling principle of asynchronized turbogenerators,deduces their mathematical model,and studies their regulating characteristics of real and reactive power(or voltage)by means of simulation calculation of operating characteristics for a 200MW asychronlzed turbogenerator.The conclusion is that the asychronlzed tubogenerators not only can regulate real and reactive power independently but also has an excellent dynamic performance. 相似文献
7.
With the development and complication of power system, the problem of low frequency oscillation in electric network becomes obvious. Unified Power Flow Controller is one of the most powerful facilities in Flexible AC Transmission Systems, which can improve the transient stability and damp the low oscillation in power system with suitable control. Considering the characteristics of inverter's output voltage magnitude, adjustment of phase and process of charge and discharge of dc capacitance, the dynamic model of UPFC is proposed by a series of nonlinear differential coefficient equations. Based on UPFC's dynamic model, the linear optimal controller of UPFC with state feedback is proposed. In this way, the low frequency oscillation is damped effectively. A simulation is processed basing the theory. 相似文献
8.
Grounded on the theory of power equilibrium, a novel single phase series active power filter (APF) is proposed . By analyzing the power equilibrium character of series APF, the control algorithm and equation are deduced. In the proposed control strategy, instead of the fundamental current detection and complex computation, only the capacitance voltage and the source current on d.c. side are needed. The clear control loop has been realized with simple circuit and the series proposed APF can compensate both reactive and harmonic current simultaneously. The simulation results show the excellent compensation effect and confirm the validity of theoretical analysis. 相似文献
9.
The purpose of a power system is to deliver the power the customers require in real time, on demand, within acceptable voltage and frequency limit, and in a reliable and economic manner. Using NLPNN (New Linear Programming Neural Network) model, the behavior analysis of power system under fault conditions is carried through. The stability and convergence theorems are set up to obtain the resolution for the problem of the load curtailment strategy. A new way is open up to evaluate the reliability of power systems and the great progress in calculation analysis model is achieved. The new calculation technique and theory foundation of reliability evaluation are supplied. 相似文献
10.
Voltage fluctuation and flicker is one of the main causation that imperils reliability of power supply. Steelmaking EAF with large load of distribution network produces large impact and interference on the public electric network in operation. So it is very important to control reactive power for voltage fluctuation and flicker mitigation. STATCOM possessing high response speed is an effective measure to mitigate voltage fluctuation and flicker of distribution network. Here, comparing to static var compensation, many advantages of STATCOM are analyzed. Operation principles COM mitigating voltage fluctuation and flicker, general control strategies and control method are introduced cussed. The researching pivot and trend in the future are also discussed. of STAT- and discussed. The researching pivot and trend in the future are also discussed. 相似文献
11.
Based on the research of a practical project of high frequency high voltage switching power supplies,the system design and experimental investigation of a single end flyback high frequency high voltage switching power supply are presented. In order to solve the problem of durable voltage of power MOSFETs that are used in the single end flyback high voltage switching power supply,an effective approach that adopts dual MOSFETs in series connected is proposed.The procedure of the designing and the parameter of each device is given in detail.A prototype of 220 Volt input and 2000V/3mA output is developed, and the validity of the scheme is demonstrated by the experiment. 相似文献
12.
This paper summarizes the requirements of standards for aircraft power supply firstly,and then points out that the input current harmonic and output DC voltage ripple should be considered seriously when designing three-phase power factor correction (PFC)for aircraft under variable line frequency and unbalanced line supply. Based on reviewing the topologies for aircraft three-phase PFC,three typical topologies,i.e. three-phase pulse width modulation (PWM)rectifier,traditional shunt active power filter (APF)and generalized APF,are picked up. A unified single-phase equivalent model is developed for comparing the harmonic suppression performance of the three active PFC schemes. And the switching stress is also calculated for evaluating their efficiency and power density. Three 5 kW PFC are designed by employing each of the three selected schemes. Simulation is carried out to verify the correctness of the theoretical analysis. The theory and simulation results indicate that the generalized APF topology shows the most technical merit for aircraft three-phase PFC. Future research works on generalized APF are also pointed out,which are solving the uncontrollability of its DC output voltage and optimal designing the filter inductors. 相似文献
13.
Since there exist high-frequency switching networks and complicated operating modes in bi-directional inductive power transfer (IPT) system, it is easy to result in high harmonics and EMI interference. An LCL filter network is introduced to effectively filter out the unwanted harmonics in track current and reduce EMI interference. Based on a mathematical model of the power transmission established by complex analysis of the AC variables, under the condition of maximum transmission efficiency, the phase angle differences between the primary input voltage and secondary output voltage U·so are ±90° and the energy is respectively transferred in forward or backward direction. Moreover, the power magnitude can be controlled by adjusting the modulus of U·pi and U·so. In addition, to keep the track current constant, different phase-shifting control strategies are designed in the primary and secondary parts. Simulation and experimental results show that these strategies can not only adjust track current to keep constant but also dynamically change the direction and magnitude of power transmission according to the working conditions and actual needs of the system load to improve the system operating efficiency. 相似文献
14.
The economic difference in Chongqing municipality is very obvious.Chongqing must suit measures to local conditions to carry out this policy.The electricity pricing is the point of balance of the power market.The policy of same electricity pricing in same net interacts with the Chongqing power market.On the ground of Chongqing municipality power market,this paper classifies the cardinal index and sets up a grey index system including the gross domestic production,per capital gross domestic production,per capita income,power management system,population density,power consumption levle,social retail amount.Region division by means of grey cluster provides the base of decision making for the successful application of same electricity pricing in same net in Chongqing municipality. 相似文献
15.
The main theortical basis that management accountant can be regarded as electricity-generating commerce is brought forward.The main contents of management accountant,such as cost analysis,quantity benefit analysis,estimate analysis,the decision analysis,the budget,cost control,responsibility center,the possibility of the indetermination analysis theories on generating electricity,feasibility and advantages,are analyzed and demonstrated in detail.Based on these works and combining knowledge of computer,related knowledge about power and the latest rules of electric power market,the functional design for the power plant biding for on-net assistant system is completed.The power plant bid decision-making stragegy includes following functions: receiving and declareing the data of the electric power market,protecting cost analysis,protecting price decision,predicting load,safe area analysis,superior distribution,settle accounts,sensitivity analysis,controlling plan management and risk analysis etc. 相似文献
16.
ZHONG Yuan chang 《保鲜与加工》2003,(1):42-44
For that the characteristics of low voltage power line channel are complicated and variable, how to use low voltage power line to realize reliable and high speed communication has always been the hottest question in power line communication field. This article introduces how to apply MSK to the low voltage power line communication. It analyses the application elements of MSK and structures the model of low voltage power line communication based on MSK. simulation result indicates that MSK modulation technology can satisfy the characteristics that the bandwidth of power line communication channel is narrow and the attenuation to the amplitude of signal is time variable and frequency selected. Also, it makes better use of the spectrum. 相似文献
17.
With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system. 相似文献
18.
In order to make good use of power line carrier to communicate, it is necessary to analyze the time-variable, impedance,attenuation and noise characteristics of low voltage power line. The waves of every characteristic have been experimented. At the same time, aiming at these characteristics, some available measures are given in order to conquer the disadvantage factors. The experimental results show that some suitable carrier communication modes must be adopted to realize ideally the carrier communication on low voltage power line. 相似文献
19.
Zhao Youxin 《保鲜与加工》1988,(4)
A new approach based on sensitivity method for the optimal power flow is presented in the paper. This method has the following advantages: it is suitable to solve a 200-node power system on the microcomputer; the convergence is easy to reach and the computation speed is quick; it is possible to reduce 8-14% power loss and to get maximum economic benefit by using this method; in power system dispatch center it can be used as an on-line voltage and reactive power control program to keep good voltage level. The proposed method has been proved successful by IEEE 118-node test system and the several real power systems such as 49-node, 61-node, 99-node and 200-node systems. 相似文献
20.
This paper describes an application of evolutionary programming(EP) to reactive power optimization and voltage control of power systems.Some technical problems which conclude mutation sacle,fitness value and population size have been solved to make EP practical for solving the optimal power flow problems.The computational results with EP have been compared with those obtained from a conventional gradient based optimization method.The comparision shows that EP are better than conventional methods in dealing with the optimization of noncontinuous and nonsmooth funcnons.The EP show the ability to search for the global optimum in reactive optimization that has multiple optima. 相似文献