CN1042265A - Pressure photoelectric protector for explosion-proof of single capacitor - Google Patents

Abstract

The invention belongs to power capacitor manufacturing technology field, be applicable to the protection of separate unit electric capacitor.Setting pressure optical sensing means on capacitor is to obtain capacitor internal pressure variable signal.Transfer in the control central console through optical cable.Circuit is arranged, trip(ping) circuit etc. in the control central console.Circuit gives the alarm or trips and cut off the electricity supply according to the character decision of signal in this.Alarm signal circuit and trip circuit be by the silicon phototriode, transistor, and relay, resistance is formed.The present invention to the pressure reacting condition fast, sensitive, accurately and reliably, can provide capacitor internal pressure variable signal, can effectively prevent capacitor case rupture again.

Description

Pressure photoelectric protector for explosion-proof of single capacitor

The invention belongs to power capacitor manufacturing technology field, is a kind of power capacitor protective device, is applicable to the complete reactive power compensator of electric power system capacitor.

The explosion-proof main mode of protection single capacitor shell is that every capacitor adds a spray-by-type fuse or only is provided with fuse in the capacitor, or both are equipped with.But statistical confirmation for many years, the capacitor rate of failure is still higher, and its raising middle flask shell distortion is expanded and bursting accident takes place a lot of every year.Only show that this class fault accounts for the whole capacitor device and damages 35.39% of number, causes very big loss to electric power system with regard to the continuous 9 years assembly averages in the Northeast.Cause the main cause of this consequence to be that main means-spray-by-type fuse and the interior fuse of protecting single capacitor to prevent the casing deformation explosion do not play a protective role.Its main cause is that fuse exists following technological deficiency:

(1) the ampere-time characteristic dispersiveness of homemade fuse is bigger, particularly in little current range; Differing greatly between the producer, individual other up to ± 169.5%.So high dispersiveness is cooperated for protection and brings very big difficulty.

(2) the ampere-time characteristic curve that provides of producer is inaccurate.This mainly be since manufactory at the selection of material, due to the coarse behaviour in aspects such as processing technology.More chief reason is: the dispersed scope of clear and definite predetermined characteristic not among the ministerial standard JB-3840-85 of Machinery Ministry promulgation, in the ampere-time characteristic curve test method of defined, formulation about " each testing site test fuse number should be no less than three " is actually the accuracy that can't guarantee its curve.

(3) requirement that cooperates according to protection, fuse should have declivitous ampere-time characteristic in little current range.Regulation (seeing 4.10) about basic operating chacteristics among the JB-3840-85 is promptly reacted this point.Obviously, steep ampere-time characteristic may cause big dispersiveness.Test shows, even after doing strict control on the technology, the ampere-time characteristic dispersiveness of some product (under certain blowout current, the dispersiveness of its fusing time) can be limited in ± and about 60%.

(4) protection philosophy of fuse is: the ampere-time characteristic curve of fuse will be worked good with capacitor case rupture characteristic curve (being the capacitor super-load damage curve); could reliably play a protective role, but homemade so far capacitor does not have a general rupture of case characteristic curve to be employed as yet.Can only cooperate with the rupture of case characteristic roughly with the fuse blows current range.And the fuse operating characteristics itself differs greatly, and this not only is meant between each producer, even between the different size of same producer, also has bigger difference, and differing more than 1 times of having (refers to mean value operate time under the same operating current multiple).

(5) the minority component breakdown may appear in the capacitor inner member, does not reach fuse operating current value at all, but inner partial discharge causes oil to continue gasification, and may make rupture of case.Run into this internal fault situation, outer fuse will not shield.

(6) the arc-extinguishing tube moisture-sensitive aliquation of existing producer product lost efficacy arc extinction performance.It is incorrect that the installation site often takes place again, and making the fusible link buttock line be obstructed by outer pipe friction can not normally eject, and influences break performance.

The single capacitor of fuse in the band, interior fuse only can be protected the fault of inner connection in series-parallel element, and the rupture of case that can not protect inner two interpolar penetrability short circuits to cause.

Therefore, no matter be interior fuse, or separate unit spray is difficult to all very reliably by the outer fuse of formula that protective ratio himself is worth expensive about 150 times shunt capacitor, especially for as the large value capacitor of 334,000 methods unreliable especially.

The capacitor pressure photoelectric protector that the purpose of this invention is to provide fuse in a kind of separate unit band can in time detect the single capacitor internal pressure and change.When pressure rises to dangerous values, only provide alarm signal; Before pressure continues to rise to rupture of case point, can quickly and effectively capacitor be cut off from electrical network, capacitor is had a power failure, stop internal pressure and rise.The capacitor internal fault can be in time found thereby reach, the appearance of the unexpected bursting accident of capacitor can be avoided again.

The present invention mainly is made up of three parts: pressure optical sensing means, Ground Control central console, optical fiber cable transmission system.The pressure optical sensing means is responsive when the capacitor internal pressure changes to the pressure in the capacitor, by blocking the light in the optical fiber optical cable transmission system, pressure changing information is transferred to central console.Central console is according to unlike signal, and decision is to report to the police or outage.

Fig. 1 is a schematic diagram of the present invention.1 capacitor among the figure, 2 pressure optical sensing means, 3 optical cables, 4 photoelectric protections control central console, 5 capacitor frameworks, 6 high voltage supporting insulators.

Fig. 2, Fig. 3 are pressure optical sensing means structure chart of the present invention.11 is glass stria tube among the figure, and 12 is pressing plate, and 13 is the light baffle plate, 14 poles, 15 springs, 16 limit casings, 17 fiber fixed frames, 18 outer covers.

Fig. 4 controls the element circuitry figure of central console 4 for the present invention

Fig. 5 controls control of central console 4 relays and signal circuit figure for the present invention.

Select the power capacitor shell that internal pressure is changed more sensitive position, generally the side or above, fixed thereon pole 14.Pressing plate 12 is enclosed within and makes its energy free movable on the pole 14.Spring 15 is placed on the pole 14, top is spacing with limit casing 16 again.Bellows 11 is placed on below the pressing plate 12,14 of poles.Bellows 11 1 ends are shut, and the other end is sealed on the capacitor case, and communicate with its inside.Light baffle plate 13 is fixed on the pressing plate 14, also between support plate 14.Fiber fixed frame 17 on the optical cable 3 usefulness outer covers 18 is fixing.When optical fiber baffle plate 13 moves on pressing plate 12, can shelter from the transmission of optical cable 3 light.As shown in Figure 2.

Optical cable 3 is drawn through outer cover 18, to the silicon phototriode of controlling in the central console 4.In the control central console 4, control circuit and light source are arranged.Control circuit is made up of two silicon phototriodes, four transistors, relay, resistance etc.Its connection as shown in Figure 4.

When capacitor 1 was in normal charging operation, the long-life light source that is contained in the control central console 4 was lasting luminous, and as Fig. 4, AA and the BB fibre-optic bundle of light in optical cable 3 reaches pressure optical sensing means 2.Receive by BB in the optical cable 3 and DD fibre-optic bundle.This light is passed control central console 4 back, is received by two silicon phototriodes respectively.Make relay J through photoswitch circuit ₁And J ₂Excitation is in starting state, and their normally closed contact is in open mode.At this moment, alarm and trip signal do not take place in the main control room.

When certain capacitor internal discharge for a certain reason, make in the insulating oil gasification and press liter, cause bellows 11 to expand, pressing plate 12 drives light baffle plates 13 and rises.Light baffle plate 13 rises to when giving the height of setting up earlier, and fibre-optic bundle AA in the optical cable 3 and the transmission line between BB cut off.At this moment, the alarm loop silicon phototriode in the control remittance control circuit turn-offs relay J ₁Lose excitation, J ₁Normally closed contact returns closure, J _1-1Excitation is connected the alarm loop, and sound equipment is sent in the alarm in the main control room.Press in this capacitor simultaneously that to rise the alarm photoflash lamp glittering.The operations staff of announcement discerns this capacitor numbering.The operations staff checks according to the power failure chance or is changed.The alarm photoflash lamp is by relay J _1-1The control of a pair of normal opened contact.

When certain capacitor for a certain reason inside rapidly arc discharge cause insulating oil to gasify fast, when interior pressure is elevated to more dangerous air pressure suddenly, bellows 11 acceleration expansions.Light baffle plate 13 rises rapidly with pressing plate 12 and gives the height determined earlier (rising highly when giving the alarm), with the transmission line cut-out of fibre-optic bundle CC in the optical cable 3 and DD.At this moment, the silicon phototriode of the trip(ping) circuit of control remittance control circuit turn-offs relay J ₂Lose excitation, J ₂Normally closed contact returns closure, J _2-1Excitation is connected trip(ping) circuit.At this moment, the loop open circuit quick-break of this group capacitor tripping operation.Send trip signal in the master-control room simultaneously.Capacitor stops to be subjected to electricity from electrical network, and inside stops discharge, and oil pressure stops to rise, and avoids occurring bursting accident.The operations staff drops into operation of power networks after this capacitor should being changed again.

By regulating the screw on the pole 14, degree of tightness spring 15, thereby the height that definite light baffle plate 13 rises.This determines that highly oil pressure is alarm or tripping operation in the capacitor, that is to say that internal oil pressure is that general rising or rapid the rising cause dangerous spot.

Must have interior fuse element protection with capacitor of the present invention, when inner member is broken down, especially interior fuse excision protection, thus reduce alarm signal action frequency of the present invention.

Bellows 11 of the present invention directly communicates with capacitor inside, when internal pressure changes, causes bellows 11 distortion.By pressing plate 12 and light baffle plate 13, the optical channel in the optical cable is cut off.The optical channel shutoff signal is transferred to control remittance control circuit, and is shown to the operations staff, and the capacitor internal oil pressure of announcement rises to certain value or cuts off the electricity supply from electrical network.Therefore, the present invention can show accurately that the capacitor oil voltage rise is high and prevent the capacitor explosion.

The present invention has following features:

1, protective reaction is accurate. Bellows 11 of the present invention directly communicates with capacitor internal, as long as its internal pressure changes, will cause that bellows produces deformation, by the pressure optical transmission system, pressure change signal is reached control remittance control circuit. Converging control circuit in control provides alarm signal or cuts off the electricity supply.

2, protective reaction speed is fast.Impel the capacitor explosion to cause by two kinds of reasons.

Proved by Multitest work that (1) capacitor inner member fault develops gradually, after surpassing about 50%, fault progression is accelerated, up to whole punctures.Draw from the capacitor case rupture test: inner member all punctures rupture of case, needs certain gathering strength the time.Simultaneously, both made element not develop into whole punctures as yet, but long-time internal discharge impels the insulating oil gasification, the case internal pressure increases to cause to a certain degree and also rupture of case might occur.In a word, taking place after second to hundreds of at several seconds to the rupture of case required time appears in this class fault.

(2) inner two interpolars (between the lead-out wire) direct-arc of capacitor punctures flashing, causes the insulating oil gasification, and internal pressure is risen suddenly, causes casing deformation to arrive explosion.Find out that from relevant test oscillogram this process is also at least at 1.6-4.67 after second, wherein split for the part in 1.6 seconds, begin jet oil spout, flew out for the shell fuse that all splits in 4.67 seconds.Also prove this point on US Westinghouse company's capacitor burst test video sheet.

Therefore, beginning from fault at least will be through 1.6 second time to rupture of case.

Be made up of following operate time of the present invention:

(1) bellows raises, and the time of the light in the blocking optical cable can be determined by the elastic force of regulating spring 15, can be decided to be 0.1 second.

(2) the unglazed ejaculation of fibre-optic bundle DD makes relay J ₂Returning, is the movement response time of transistor optoelectronic switch during this period of time, about 6 microseconds.

(3) relay J ₂Return, its normally closed contact returns, and connects the circuit trip(ping) circuit, sends trip command, through 0.01 second operate time of fast tripping protection, adds time trip time of opening circuit again) 0.08 second, need 0.09 second altogether.

Therefore, the present invention occurs to circuit breaker trip from fault, needs 0.19 second altogether, much smaller than 1.6 seconds capacitor explosion time.

3, Bao Hu reliability.Adopted optical fiber, made the signal transmission not be subjected to electromagnetic interference.The present invention can be transmitted to light between High-Voltage Insulation platform and the ground zero potential reliably, again can the isolated high-voltage insulation pad and ground between conductivity.

4, Bao Hu sensitivity.Owing to adopted pressure is changed more sensitive bellows 11, made to change that bellows 11 will produce deformation in capacitor internal pressure one.In addition because two disconnected protected modes, can in time provide capacitor pressure rising signal or cut off the electricity supply, reach and prevent its explosion purpose.

Fig. 6～Figure 13 is specific embodiments of the invention. Fig. 6～Fig. 9 is applied in design drawing in the engineering for the present invention, and wherein Fig. 6 is plane, and Fig. 7, Fig. 8 are sectional drawing, and Fig. 9 is the wiring layout drawing. Figure 10～Figure 13 is design drawing of the present invention, has marked the model of element among the figure, the specification of each several part.

The pressure optical sensing means is placed on the capacitor top cover, by the shell binding post. In capacitor case processing, increase a hole at the top cover position, with dress ripple pipe 11, to load onto simultaneously two poles. Be connected with bolt with shell, and add the weldering sealing, airtight quality is very reliable, the inspection of pressurizeing. Bellows adopts Stainless Steel. Bellows 11, light baffle plate 13, pole 14, the manufacturing of fiber fixed frame, outer cover 18 and installation dimension error are in ± 1mm.

Every optical cable has a lot of thin glass optical waveguide fibres by four bundle glass optical waveguide fibre Shu Zucheng in every bundle glass optical waveguide fibre bundle, it is 2mm that plying forms diameter. Every bundle outsourcing silicon rubber plastic sheath, wall thickness is about 0.2mm. The crosslinked polyetylene insulated sheath of optical cable outsourcing. The optical cable that is on the High-Voltage Insulation platform is established multiple bundle cable thermal shrinkage type terminals. Every bundle glass optical waveguide fibre two ends are sealed admittedly with optical cement, and reach optics fineness through polishing, and its transmissivity is not less than 60%.

Claims (4)

1, the protection of single capacitor has outer spray-by-type fuse, interior fuse; the invention is characterized in and having setting pressure optical sensing means on the inner fuse capacitor; the optical fiber cable transmission system; with the control central console; the pressure optical sensing means communicates with capacitor; take out pressure change signal,, reach in the control central console through the optical fiber cable transmission system.

2, capacitor pressure photoelectric protector according to claim 1; it is characterized in that the bellows in the pressure optical sensor communicates with capacitor inside; when the capacitor internal pressure raises; the bellows distortion is expanded; make the light plate washer on the pressing plate move; move to when determining the position, shelter from the optical cable between fibre-optic bundle AA and BB and the transmission of light between CC and DD, and be reacted to the control central console by optical cable.

3, capacitor pressure photoelectric protector according to claim 2; it is characterized in that controlling warning circuit and trip(ping) circuit are arranged in the central console; when the light plate washer sheltered from fibre-optic bundle AA in the optical cable and BB, the silicon phototriode in the circuit for alarming made relay J ₁The normally closed contact closure, the signal that gives the alarm, when the light baffle plate sheltered from fibre-optic bundle CC in the optical cable and DD, the silicon phototriode in the trip(ping) circuit made the relay J in the trip(ping) circuit ₂The normally closed contact closure, circuit tripping operation, power cutoff.

4, capacitor pressure photoelectric protector according to claim 2 is characterized in that pressing plate is spacing on pole, and it is moved around on pole, and strut fixation is on capacitor case, and the position of moving is by the decision of the spring on the pole.

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