电气专业毕业设计英文文献.docx

1、电气专业毕业设计英文文献外文资料与中文翻译外文资料：Relay protection present situation and development一、Relay protection development present situationElectrical power systems swift development to the relay protection proposed unceasingly the new request, the electronic technology, the computer technology and communications s

2、wift development unceasingly has infused the new vigor for the relay protection technologys development, therefore, the relay protection technology is advantageous, has completed the development 4 historical stage in 40 remaining years of time.After the founding of the nation, our country relay prot

3、ection discipline, the relay protection design, the relay factory industry and the relay protection technical team grows out of nothing, has passed through the path which in about 10 year the advanced countries half century pass through. In the 50s, our country engineers and technicians creatively a

4、bsorption, the digestion, have grasped the overseas advanced relay protection equipment performance and the movement technology 1, completed one to have the deep relay protection theory attainments and the rich service experiences relay protection technical team, and grew the instruction function to

5、 the national relay protection technical teams establishment. The Acheng relay factory introduction has digested at that time the overseas advanced relay technique of manufacture, has established our country own relay manufacturing industry. Therefore our country has completed the relay protection r

6、esearch, the design, the manufacture, the movement and the teaching complete system in the 60s. This is the mechanical and electrical -like relay protection prosperous time, was our country relay protection technology development has laid the solid foundation.From the late 50s, the transistor relay

7、protection was starting to study. In the 60s to the 80s in is the time which the transistor relay protection vigorous development and widely uses. And the Tianjin University and the Nanjing Electric power Automation Plant cooperation researchs 500kv transistor direction high frequency protection dev

8、elops with the Nanjing Electric power Automation Research institute the transistor high frequency block system is away from the protection, moves on the Gezhou Dam 500 kv lines 2, finished the 500kv line protection to depend upon completely from the overseas import time.From the 70s, started based o

9、n the integration operational amplifiers integrated circuit protection to study. Has formed the complete series to the late 80s integrated circuit protection, substitutes for the transistor protection gradually. The development which, the production, the application protected to the early 90s integr

10、ated circuit were still in the dominant position, this was the integrated circuit protection time. The integrated circuit power frequency change quantity direction which develops in this aspect Nanjing Electric power Automation Research institute high frequency protected the influential role 3, the

11、Tianjin University and the Nanjing Electric power Automation Plant cooperation developments integrated circuit phase voltage compensation type direction high frequency protection also moved in many 220kv and on the 500kv line.Our country namely started the computer relay protection research from the

12、 late 70s 4, the institutions of higher learning and the scientific research courtyard institute forerunners function. Huazhong University of Science and Technology, the Southeast University, the North China electric power institute, Xian Jiaotong University, the Tianjin University, Shanghai Jiaoton

13、g University, the Chongqing University and the Nanjing Electric power Automation Research institute one after another has developed the different principle, the different pattern microcomputer protective device. in 1984 the original North China electric power institute developed the transmission lin

14、e microcomputer protective device first through the appraisal, and obtained the application in the system 5, has opened in our country relay protection history the new page, protected the promotion for the microcomputer to pave the way. In the main equipment protection aspect, the generator which th

15、e Southeast University and Huazhong University of Science and Technology develops loses magnetism protection, the generator protection and the generator? Bank of transformers protection also one after another in 1989, in 1994 through appraisal, investment movement. The Nanjing Electric power Automat

16、ion Research institute develops microcomputer line protective device also in 1991 through appraisal. Tianjin University and Nanjing Electric power Automation Plant cooperation development microcomputer phase voltage compensation type direction high frequency protection, Xian Jiaotong University and

17、Xuchang relay factory cooperation development positive sequence breakdown component direction high frequency protection also one after another in 1993, in 1996 through appraisal. Hence, the different principle, the different types microcomputer line and the main equipment protect unique, provided on

18、e group of new generation performance for the electrical power system to be fine, the function was complete, operation reliable relay protection installment. Along with the microcomputer protective devices research, in microcomputer aspects and so on protection software, algorithm has also made many

19、 theory progresses. May say that started our country relay protection technology from the 90s to enter the time which the microcomputer protected.二、future development of Relay protection The future trend of relay protection technology is to computerization, networking is intelligent, protect, contro

20、l, measure and data communication developing by integration. The principles of protection of electric power circuits are quite independent of the relay designs which may be applied. For example, if the current to an electric circuit or a machine is greater than that which can be tolerated, it is nec

21、essary to take remedial action. The device for recognizing the condition and initiating corrective measures would be termed as an over-current relay regardless of the mechanists by which the function would be accomplished. Because the functions of electromechanical devices are easily described, thei

22、r performance wills ever as a basis for presenting a description of relays and relay systems in general.Relays must have the following characteristics:Reliability-The nature of the problem is that the relay may be idle for periods extending into years and then be required to operate with fast respon

23、ds, as intended, the first time. The penalty for failure to operate properly may run into millions of dollars.Selectivity-The relay must not respond to abnormal, but harmless, system conditions such as switching transients or sudden changes in load.Sensitivity-The relay must not fail to operate, eve

24、n in borderline situations, when operation was planned.Speed-The relay should make the decision to act as close to instantaneously as possible. If intentional time delay is available, it should be predictable and precisely adjustable.Instantaneous-The term means no intentional time delay.There are s

25、everal possible ways to classify relays: by function, by construction, by application. Relays are one of two basic types of construction: electromagnetic or solid-state. The electromagnetic type relies on the development of electromagnetic forces on movable members, which provide switching action by

26、 physically opening or closing sets of contacts. The solid state variety provides switching action with no physical motion by changing the state of serially connected solid state component from no conducting to conducting(or vice versa). Electromagnetic relays are older and more widely used; solid s

27、tate relays are more versatile, potentially more reliable, and fast.1）ComputerizationWith swift and violent development of computer hardware, computer protect hardware develop constantly even. The power system is improving to the demand that the computer protects constantly, besides basic function p

28、rotected, should with trouble information of the large capacity and data the long-term parking space also, fast data processing function, strong communication capacity, network in order to share the whole system data , information , ability , network of resource with other protection , control devic

29、e , dispatcher, high-level language programming ,etc. This requires computer protector to have function which is equivalent to a pc machine. In computer is it develop initial stage to protect, is it make with one minicom relay protection install to imagine. Because the small-scale organism was accum

30、ulated greatly, with high costs at that time, dependability was bad, this imagined it was unrealistic . Now, exceed the minicomputer of those years greatly with computer protector size similar worker function , speed , memory capacity of accusing of machine, so make with complete sets of worker pers

31、on who accuse of opportunity of relay protection already ripe, this will be one of the developing direction that a computer is protected . Tianjin university is it spend whom transformation act as continue the electric protector with computer protector structure self-same one worker person who accus

32、e of to develop into already. The advantage of this kind of device is as follows, (1)it have functions of 486pc,it can meet to at present and it is various kinds of function demand where computer protect future. (2)The size and structure are similar to present computer protector , the craft is super

33、ior, takes precautions against earthquakes , defends overheatedly and defending the electromagnetic ability of interfering strongly, can operate it in very abominable working environment , the cost is acceptable. (3)Adopting std bus or pc bus, hardware module , can select different module for use to different protection wanton