电气英语论文

1、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-life. fo

2、r 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 constru

3、ction 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 make t

4、he 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 brought a ne

5、w 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 elect

6、ric 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 power sy-

7、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 presents t

8、he 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 line prob

9、lem, 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 reconstruction,

10、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 state

11、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 bad da

12、ta 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 tested in

13、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 means.

14、 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 on comp

15、ensation, 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 decreas

16、ing 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 electric p

17、ower 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 origi

18、nal 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 the tota

19、l 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 about neu

20、tral 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, neutral

21、 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 insulating l

22、evel. 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 of ne

23、w- 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 choice the

24、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 comparison. it

25、 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 network

26、 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 mode of

27、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 earth prot

28、ection 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 ground

29、ing 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 conclusions in t

30、his 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 point tha

31、t 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 improve the

32、 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 less

33、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 var

34、ious line modes, according to the characteristics various line modes existed in the electric distribution net in foshan.first, the thesis introduces as the different line modes in the l0kv electric distribution net and in some foreign countries. making it clear tow to conduct analyzing on the line m

35、ode of the electric distribution net, and telling us how important and necessary that analyses are.second, it turns to the necessity of calculating the number of optimization subsection, elaborating how it influences on the economy and reliability. then by building up the calculation mode of the num

36、ber of optimization subsection it introduces different power supply projects on the different line modes in brief. third, it carries on the calculation and analyses towards the reliability and economy of the different line modes of electric distribution net, describing drafts according by the calcul

37、ation. then it makes analysis and discussion on the number of optimization subsection.at last, the article make conclusion on the economy and reliability of different line modes, as well as, its application situation. accordion to the actual circumstance, the thesis puts forward the beneficial sugge

38、stion on the programming and construction of the l0kv electric distribution net in all areas in foshan. providing the basic theories and beneficial guideline for the programming design of the lokv electric distribution net and building up a solid net, reasonable layout, qualified safe and efficientl

39、y-worked electric distribution net.references 1 wencheng su. factories power supply m. machinery industry publishing house. 1999.92 jiecai liu. factories power supply design guidance m. machinery industry publishing house.1999.123 power supply and distribution system design specificationss.china pla

40、ns press. 19964 low-voltage distribution design specifications s.china plans press. 1996.6fire fightingalong with the our country economic development rapid development, the lives of the people level unceasing enhancement, the city uses to be day by day anxious, urges the building to face the direct

41、ion is developing. this kind of high level civil construction repair needed materials and the way also more hasten the diversification, and along with uses electricity the load and coal gas consumption quantity enlarging, proposed to the fire auto-alarm system design is higher, a stricter request. i

42、n order to guarantee the people life and property the security, the fire auto-alarm system design has become in the high level civil construction design one of most important design contents. presently based on the author fire of auto-alarm system design overseeing work in the high level civil build

43、ing experience, proposed in present national related standard and standard unclear true detail shallow opinion, by for the colleagues to discuss and to point out mistakes. first, design basisthe fire auto-alarm system design is a specialized very strong technology work, at the same time also has the

44、 very strong policy-type. therefore, first should be clear about the following design basis:1st, must grasp the architectural design fire protection standard, the system design standard, the equipment manufacture standard, the installment construction approval standard and the administration laws an

45、d regulations and so on five big aspects fire laws and regulations, and in practical understanding present country related standard and standard positive word: must, be supposed, to be suitable, may and the reverse side word: strictly prohibits, should not, not have, not to be suitable the meaning.2

46、nd, must aim at high level civil building function, use and the protection object fire protection rank, earnestly carries out the present national related standard and the standard, earnestly treats the public security fire prevention surveillance department the examination and approval opinion.seco

47、nd, fire auto-alarm system equipment establishmentfire detector establishmentopens wide either the seal or the stair hall should alone divide the search coverage, and each 2 3 establish a fire detector.the first room (including guards against in front of smoke stair hall in front of room, fire eleva

48、tor room, fire elevator with guards against the front room which smoke stair hall comes in handy) and the aisle should distinguish alone to divide the search coverage, specially front the room and the lift well, the scattered stair hall and the aisle are interlinked, has time the fire haze to be eas

49、ier to gather or to flow, is the personnel disperses which saves goal with the fire prevention, therefore should install the fire detector. regarding common elevator in front of room although is not the personnel disperses , but this front room and the lift well are interlinked, has time the fire ha

50、ze to be also easy to gather or to flow, suitably alone divides the search coverage and installs the fire detector. the electric cable shaft therefore is easy to form pulls out the smoke inflammation the channel; has when the fire the fire intensity not easily extends along the electric cable burns,

51、 for this, the high level civil construction design fire protection standard and the civil construction electricity design standard separately proposes the detailed specific stipulation in the construction and in the electric wire or on the electric cable shaping. but considered implements specifica

52、lly the difficulty and the present situation, the electric cable shaft installs the fire detector is extremely essential, and coordinates the shaft the fire protection separation request, each 2 3 or each level installs.the elevator machine room should install the fire detector, its elevator is the

53、important vertical transportation vehicle; its two elevator machine room has has the fire risk; its three lift well existence essential opens the hole, like the level gate opens between the hole, the air vent, the between permanence opens the hole with the elevator machine room or the pulley and so

54、on; its four when has the fire, the lift well often becomes the fire intensity spread the channel, is easy to threaten the elevator machine room the facility. therefore, the elevator machine room establishes the fire detector is necessary, crown of also suitable establishment fire detector lift well

55、.2nd, the manual fire reports to the police the button establishment(including guards against in front of smoke stair hall in view of various floors front room in front of room, fire elevator room, fire elevator with guards against which smoke stair hall to come in handy the front room) is has when

56、the fire the personnel to disperse which saves goal with fire prevention, should report to the police the button first choice spot as the establishment manual fire. in addition, the room also should establish the manual fire to the common elevator in front of to report to the police the button.in th

57、e public active place (including hall, hall, dining room, multi-purpose hall and so on) and the main thoroughfare and so on place, the personnel very is all centralized, and mainly disperses the channel. therefore should report to the police the button in these public active places main access estab

58、lishment manual fires; the manual fire establishes which in the main thoroughfare reports to the police the button to guarantee to a manual fire which most is close to reports to the police the button distance from a fire protection district any position not to be supposed to be bigger than 30 meter

59、s.3rd, the fire emergency broadcasts the speaker the establishmentthe aisle, the hall, the dining room and so on the public place personnel very are all centralized, and mainly disperses the channel. therefore should press in these public places to a recent speaker distance is not bigger than 25 meters from a fire protection district any spot and in the aisle last should not be bigger than 12.5 meters the speaker to the aisle terminal distance the est