电气英语论文.docx

1、电气英语论文Power Supply and Distribution SystemABSTRACT: The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key point that connects the power supply with the electricity using on the industry, business and daily-li

2、fe. For the electric power, allcostumers expect to pay the lowest price for the highest reliability, but dont consider that its self-contradictory in the co-existence of economy and reliable.To improve the reliability of the power supply network, we must increase the investment cost of the network c

3、onstruction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is less than the increasing investment on improving the reliability .Thus we find out a balance point to

4、make the most economic,between the investment and the loss by calculating the investment on power net and the loss brought from power-off.KEYWORDS: power supply and distribution, power distribution reliability，reactive compensation, load distributionThe revolution of electric power system has brough

5、t a new big round construction,which is pushing the greater revolution of electric power technique along with the application of new technique and advanced equipment. Especially, the combination of the information technique and electric power technique, to great ex- tent, has improved reliability on

6、 electric quality and electric supply. The technical development decreases the cost on electric construction and drives innovation of electric network. On the basis of national and internatio- nal advanced electric knowledge, the dissertation introduces the research hotspot for present electric powe

7、r sy- etem as following.Firstly, This dissertation introduces the building condition of distribution automation(DA), and brings forward two typical construction modes on DA construction, integrative mode and fission mode .It emphasize the DA structure under the condition of the fission mode and pres

8、ents the system configuration, the main station scheme, the feeder scheme, the optimized communication scheme etc., which is for DA research reference.Secondly, as for the (DA) trouble measurement, position, isolation and resume, This dissertation analyzes the changes of pressure and current for lin

9、e problem, gets math equation by educing phase short circuit and problem position under the condition of single-phase and works out equation and several parameter s U& , s I& and e I& table on problem . It brings out optimized isolation and resume plan, realizes auto isolation and network reconstruc

10、tion, reduces the power off range and time and improves the reliability of electric power supply through problem self- diagnoses and self-analysis. It also introduces software flow and use for problem judgement and sets a model on network reconstruction and computer flow.Thirdly, electricity system

11、state is estimated to be one of the key techniques in DA realization. The dissertation recommends the resolvent of bad measurement data and structure mistake on the ground of describing state estimate way. It also advances a practical test and judging way on topology mistake in state estimate about

12、bad data test and abnormity in state estimate as well as the problem and effect on bad data from state measure to state estimate .As for real time monitor and control problem, the dissertation introduces a new way to solve them by electricity break and exceptional analysis, and the way has been test

13、ed in Weifang DA.Fourthly, about the difficulty for building the model of load forecasting, big parameter scatter limit and something concerned, the dissertation introduces some parameters, eg. weather factor, date type and social environment effect based on analysis of routine load forecasting and

14、means. It presents the way for electricity load forecasting founded on neural network(ANN),which has been tested its validity by example and made to be good practical effect.Fifthly, concerning the lack of concordant wave on preve nting concordant wave and non-power compensation and non-continuity o

15、n compensation, there is a topology structure of PWM main circuit and nonpower theory on active filter the waves technique and builds flat proof on the ground of Saber Designer and proves to be practical. Meanwhile, it analyzes and designs the way of non-power need of electric network tre- nds and d

16、ecreasing line loss combined with DA, which have been tested its objective economic benefit throu- gh counting example.Sixthly, not only do the dissertation design a way founded on the magrginal electric price fitted to our present national electric power market with regards to future trends of elec

17、tric power market in China and fair trade under the government surveillance, that is group competitio n in short-term trade under the way of grouped price and quantity harmony, but also puts forward combination arithmetic, math model of trading plan and safty economical restriction. It can solve the

18、 original contradiction between medium and long term contract price and short term competitive price with improvement on competitive percentage and cut down the unfair income difference of electric factory, at the same time, it can optimize the electric limit for all electric factories and reduce th

19、e total purchase charge of electric power from burthen curve of whole electric market network.The distribution network is an important link among the power system. Its neutral grounding mode and operation connects security and stability of the power system directly. At the same time, the problem abo

20、ut neutral grounding is associated with national conditions, natural environment, device fabrication and operation. For example, the activity situation of the thunder and lightning, insulating structure and the peripheral interference will influence the choice of neutral grounding mode Conversely, n

21、eutral grounding mode affects design, operation, debugs and developing. Generally in the system higher in grade in the voltage, the insulating expenses account for more sizable proportion at the total price of the equipment. It is very remarkable to bring the economic benefits by reducing the insula

22、ting level. Usually such system adopt the neutral directly grounding and adopt the autoreclosing to guarantee power supply reliability. On the contrary, the system which is lower in the voltage adopts neutral none grounding to raise power supply reliability. So it is an important subject to make use

23、 of new- type earth device to apply to the distribution network under considering the situation in such factors of various fields as power supply reliability, safety factor, over-voltage factor, the choice of relay protection, investment cost, etc.The main work of this paper is to research and choic

24、e the neutral grounding mode of the l0kV distribution network. The neutral grounding mode of the l0kV network mainly adopts none grounding, grounding by arc suppressing coil, grounding by reactance grounding and directly grounding. The best grounding mode is confirmed through the technology comparis

25、on. It can help the network run in safety and limit the earth electric arc by using auto-tracking compensate device and using the line protection with the detection of the sensitive small ground current. The paper introduces and analyzes the characteristic of all kind of grounding modes about l0kV n

26、etwork at first. With the comparison with technological and economy, the conclusion is drawn that the improved arc suppressing coil grounding mode shows a very big development potential.Then, this paper researches and introduces some operation characteristics of the arc suppressing coil grounding mo

27、de of the l0kV distribution network. And then the paper put emphasis on how to extinguish the earth electric arc effectively by utilizing the resonance principle. This paper combines the development of domestic and international technology and innovative achievement, and introduces the computer eart

28、h protection and autotracking compensate device. It proves that the improved arc suppressing coil grounding mode have better operation characteristics in power supply reliability, personal security, security of equipment and interference of communication. The application of the arc suppressing coil

29、grounding mode is also researched in this paper.Finally, the paper summarizes this topic research. As a result of the domination of the arc suppressing coil grounding mode, it should be more popularized and applied in the distribution network in the future.The way of thinking, project and conclusion

30、s in this thesis have effect on the research to choose the neutral grounding mode not only in I0kV distribution network but also in other power system.The basic function of the electric power system is to transport the electric power towards customers. The l0kV electric distribution net is a key poi

31、nt that connects the power supply with the electricity using on the industry, business and daily-life. For the electric power, all costumers expect to pay the lowest price for the highest reliability, but dont consider that its self-contradictory in the co-existence of economy and reliable. To impro

32、ve the reliability of the power supply network, we must increase the investment cost of the network con- struction But, if the cost that improve the reliability of the network construction, but the investment on this kind of construction would be worthless if the reducing loss is on the power-off is

33、 less than the increasing investment on improving the reliability .Thus we find out a balance point to make the most economic, between the investment and the loss by calculating the investment on power net and the loss brought from power-off. The thesis analyses on the economic and the reliable of the various line modes, according to the characteristics vario