继电器在高压开关中的正确应用.docx

1、继电器在高压开关中的正确应用Page1.Relays in high voltage switch the correct application(继电器在高压开关中的正确运用)1.English textFirstly,almost Assyria Current use of hv switchgear quadratic system by a multitude of relays, more contacts auxiliary switch and travel switch and composed pressure switch components, including re

2、lays class in proportion of the about 70%, facing the complex complex relays products, how to choose, correctly use, is the system development, design personnel close attention and should give priority to the actual problems, especially as hv switchgear quadratic control section, use plenty of relay

3、s, in its operation also has its unique particularity, selection of willpower, directly related to the substation equipment reliable safety runs, in case of accident will be particularly severe, so to achieve reasonable selection, correctly use, we must fully research analysis system of practical ap

4、plication condition and actual technical parameters of the proposed requirements, rightly chosen relays products must achieve technical performance, the whole system design, and on the basis of the importance of the whole system, reliability, by use of environmental conditions and cost factors such

5、as comprehensive consideration of the rational choice of relays.Secondly,to use environmental conditions of choice Climate stress elements, is mainly refers to temperature, humidity, air pressure (altitude), coastal atmospheric (salt fog corrosion), dust pollution, chemical gas and electromagnetic i

6、nterference factors, considering the high voltage switch in many bad working conditions, especially as wide operating equipment running high voltage circuit breaker in outdoor environment, work situation worse, and undertakes the particularity and reliable operation system key parts must choose thos

7、e who have high altitude, strong resistance of whole sealing products, because only full seal of relay will has good long-term tolerance atrocious environmental performance, excellent electrical contact is stable, reliable switching load ability. 1. Effect of temperature on the relayRelays are afrai

8、d of heat components, high temperature can accelerate relays internal plastics and insulating materials of aging, contact oxidation corrosion and extinguish arc difficulties, electric components technical parameters, the decay reliability is reduced, due to the high voltage switch inner is equipped

9、with flooding boom and insulation of heater, therefore, in the whole system design will not relay near flooding boom and insulation heaters and should remain good ventilated condition. Although relay is afraid of heat components, but low temperature also cannot ignore, low temperature can make conta

10、cts cold nien action intensifies, contacts the surface up the dew, many manufacturers of relay shows that the lowest temperature for a 25 , but the high voltage switch application in alpine region also be absent a few, because this proposal sized note onservative, avoid relays in low temperature and

11、 unreliable, appropriate in alpine region increased heaters, ensure relay at low temperatures and reliable operation, ensure the stable operation of the system. 2.Depression of relaysIn the effect of depression conditions, the relay of the radiation condition becomes worse, coil temperature rise, ma

12、ke the relay given suction close, release parameters change, affect the normal work, depression relay still can make the relay insulation resistance is reduced, contacts extinguish arc difficulties, easy to make contacts burn, the reliability of the fusion influence relays, aiming at depression cond

13、itions, the proposal USES machine sealing method. 3.The influence of mechanical stress of relaysMainly refers to the vibration and impact, collision stress elements for the control system of seismic stress resistant effect, as well as mechanical stress, the high voltage switch circuit breaker in vib

14、ration and points off the vibrations caused operation of relays more influence, should choose the bit institutions in balance, ask for electromagnetic relays reed relays are hang beam structure, the inherent frequency low, oscillation and impact can cause resonance, cause the relay contact pressure

15、drops, easy to produce instant disconnect or contacts appear jitter, affect the reliability of the relay, the proposal in the design make use vibration-proof measures to prevent produce resonance. 4.The influence of insulation voltage to relayThe sealed pressure or sealed relays derivation of the di

16、stal exposed long-term exposure to dust, moisture insulator factors, which causes the pollution of dielectric strength, it is apt to cause the insulation decline, so the breakdown failure should pay attention to the following: (1) enough creepage distance: general requirement not less than 3 mm, (2)

17、 enough insulation intensity: no electrical connection between the conductor is greater than AC2000V face contacts between more than AC1000V. (3) long-term tolerance climate stress ability: coil mouldproof broken, electrical insulation resistance level long-term stable and reliable. 5.Contact output

18、 (in) the influence of pick up circuit loadMainly refers to contact load properties, such as: light load, motor load, inductors, contactor (relays) coil, resistance sex load, etc; Contact load measure (open-circuit voltage value, closed-circuit current value), be like: low level load, dry circuit lo

19、ad, low current load, large current load, etc. Any automation equipment must be practical identification required for practical load properties, load vector-valued size, selecting proper relays product particularly important. Relay failure or reliable unreliable, mainly refers to the contacts can co

20、mplete all provisions of switching circuit function. If the actual load switch with selected relays provisions of switching load inconsistencies, reliability will be mentioned.Thirdly,use of relays should pay attention to the special problems and analysis1. About hermetic relay with the hermetic rel

21、ay part of engineering and technical personnel think that the sealing products action intuitive, failure analysis convenient while whole sealing products action process of invisiblet fathom, subjective determination not sealing products than whole sealing products more reliable, this kind of intuiti

22、on and determination of conception is very wrong. The hermetic relay advantage is used more clap well-formed bit and simple in structure, manufacture process is simple and convenient installation and easy maintenance, working condition, intuitive, and facilitate failure analysis, cheap price. The ma

23、jor disadvantage is the working reliability of use environment (climate stress, mechanical stress) change the sensitivity of the strong, long-term tolerance climatic conditions properties increased over time is susceptible to environmental conditions pollution, injury, electrical contact stability,

24、poor reliability, coil easy to generate electricity damp or impurity pollution corrosion, mildew and failure. All the hermetic relay advantage is used more balanced rotary bit and totally-sealing institutions isolation external climate stress, resistant to bad environment fine performance, the conta

25、cts electrical contact performance is stable and reliable, coil corrosion, mildew, and long-term reliable excellent performance, defect is complex structure, manufacturing processes complex, failure analysis difficulties, itself cannot repair after repeated use, cost prices high. Therefore, from the

26、 long-term climate stress resistance performance of atrocious environmental performance and electrical contact stable reliability consideration, all the hermetic relay superior to the hermetic relay, especially for high voltage switch used in relays products, should choose totally-sealing relays, so

27、 can adapt to power automatic control, long-term stable particularity request.2. Relay contacts of parallel and series relay contacts parallel used doesnt improve its load current relay, because many groups of the contacts action is absolutely not simultaneously movement, namely first connect with t

28、he group 1 contacts first switch enhanced load, and parallel other contacts havent action, it is easy to make contacts damage without contact or welded which could not disconnect, contacts to break parallel error can be reduced failure rate, but to stick mistakes, by contrast, due to break contacts

29、mistakes as the main failure modes, it shall be sure to improve reliability in parallel, can use in key parts. For example: in high voltage circuit breaker implements three extremely electrical linkage, using relay action to drive 3 normally open contacts closed, then respectively driven 3 unipolar

30、electromagnets finish points off operation, at that time relay namely points off three pairs of relays normally open contacts May 2 1 groups in parallel, played a key role, see figure 1. Use the working voltage of not higher than relays coil maximum working voltage, also do not less than 90% of the

31、rated voltage, otherwise you will endanger coil life and reliability in use.Contacts can improve its load voltage series, improve multiples namely for the tandem contacts the number of groups, contacts in the series of stick mistakes can increase its reliability, but to break mistakes opposite. For

32、example: some high voltage circuit breaker points close brake operating circuit will of auxiliary switch contacts parallel or series, is according to the operation load current to decide. In order to operate more reliable, suggestion will auxiliary switch contacts are parallel, ensure the action of

33、reliable, played a key protection, see figure 3, as shown in figure 3 parallel type Suggestions.3. Relay contacts the correct connection (1) In power automation control operation, try to move close contacts, less with dynamic break contacts, namely the relay contacts the connection, should try to use more move close contacts connection. Us