CN1126133C

CN1126133C - Self-protection tripping mechanism for subway electric transformer

Info

Publication number: CN1126133C
Application number: CN 98109643
Authority: CN
Inventors: 雅克·维尔德; 米歇尔·萨科蒂
Original assignee: FRANCE TRANSFORMER Co
Current assignee: FRANCE TRANSFORMER Co
Priority date: 1997-06-03
Filing date: 1998-06-03
Publication date: 2003-10-29
Anticipated expiration: 2018-06-03
Also published as: EP0883222B1; FR2764130B1; ES2236846T3; EP0883222A1; FR2764130A1; DE69828842T2; CN1201246A; DE69828842D1; RU2213406C2

Abstract

The arrangement comprises a light lever (6) made from, e.g. polypropylene. The lever is asymmetrically arranged about a pivot (7). When the lever is horizontal, its shorter arm (8) just fails to contact, with its finger (11), an actuator (2) of a trip-switch (5) that controls a primary side circuit-breaker. An open-topped (20) cup (10), terminates a longer arm (9) of the lever and is filled with oil. Initially, at the end of the tank filling process the arm swings up vertically as the oil rises in the tank; its movement being halted by a tank lid stop (12). If the tank leaks (17,13), the finger rises against the actuator to apply a force (Fd) mainly due to the weight of oil in the cup, which, at a preset value, overcomes the actuator resistance and trips the circuit-breaker, optionally, after a time delay.

Description

The self-shield tripping mechanism that is used for the immersion piezoelectric transformer

Technical field

The present invention relates to the power transformer field or be used for the distribution transformer field; More precisely, the subway transformer field that relates to self-shield.

Background technology

To look back below, subway transformer is a kind of the transformer that cools off in the dielectric fluid of its electric winding and a kind of mineral oil that is loaded on stuffing box of magnetic circuit immersion and so on.When transformer comprises a system that is loaded in its case, this system does not provide external energy under the situation of the internal breakdown that may cause the case blast, can just transformer be called " self-shield " a winding of transformer when power supply disconnects yet.As the example of this puncture, can enumerate: because the result that dielectric fluid leaks from stuffing box, fluid level descends abnormally; Perhaps the excessive pressure of dielectric fluid raises.European patent application EP-the A-0 that proposes the applicant in 653,765, perhaps delivers document at other, and EP-0 for example in 093,076 or USP4,223,364, has described a detailed example that is exclusively used in the whole Self-Protection Subsystem of polyphase transformer.

Above-mentioned Self-Protection Subsystem generally includes a circuit breaker; on circuit breaker, there is an exciter to work; exciter itself is encouraged by a tripping mechanism; tripping mechanism comprises a checkout equipment that the dielectric fluid parameter is changed sensitivity; these parameters change can express to stuffing box brings dangerous unusual possible state, and these parameters have the temperature and pressure of stuffing box intermediate current body or surface level etc.

The present invention is used for the Self-Protection Subsystem of following type: it comprises that one changes responsive tripping mechanism to liquid level at least, is used to prevent that because the danger that the loss of dielectric cooling fluid causes, for instance, the stuffing box leakage can cause this fluid loss; Thereby when this liquid level reaches a unusual low value, make the protection unit trip.

Above-mentioned tripping mechanism can be a kind of mechanism that is made up of a buoyancy aid, and this buoyancy aid is made less than the material (for example polystyrene) of dielectric fluid density by a kind of its density, therefore the liquid level that can follow the tracks of fluid in principle reliably.Yet the overtime behavior of buoyancy aid equipment can not be entirely satisfactory.If be about 30 years or more than 30 years the useful life of the transformer of given the above-mentioned type, then must be, buoyancy aid finishes its life-span owing to oil infiltration, if the obvious porous of buoyancy aid especially, then all the more so, this is because buoyancy aid experiences the cause of pressurization-step-down circulation enduringly.

Under these conditions, buoyancy aid is lost its floating ability gradually, the situation that this just may cause protection equipment to trip in advance, thus always very expensive, because need manual intervention to go to dismantle the top of transformer, so that it is resetted.

It is contemplated that, remove to replace conventional buoyancy aid with some impermeable hollow containers that are full of air.Yet; this container needs to regulate fine the sensitivity of protection equipment; also be difficult to carry out; although this is because it is in light weight; but it must be in the whole length of life of transformer; can vacuum-resistant (transformer vacuumizes) and high pressure resistant (at work, the overvoltage of transformer can reach 0.2 millibar), and high temperature resistant (usually above 100 ℃).

Summary of the invention

The objective of the invention is to provides a kind of simple and inexpensive equipment to the producer of self-shield immersion piezoelectric transformer; this equipment is to the liquid level sensitivity of dielectric cooling fluid in the stuffing box; and have when unusual in this liquid level; can guarantee that self-shield equipment trips effectively and reliable all the time in the whole length of life of transformer.

According to this purpose; theme of the present invention is a kind of tripping mechanism that interior installing is equipped with that is used as; be used for carrying out self-shield to being immersed in a piezoelectric transformer of filling with the case of dielectric cooling fluid; its method is when unusual decline appears in the liquid level of dielectric fluid, disconnects winding of transformer from power supply grid.This equipment comprises the circuit breaker that exciter of a usefulness is applied to it, and exciter itself is encouraged by described tripping mechanism, and this tripping mechanism comprises that has a container that enters opening.This tripping mechanism comprises one on the one hand around the lever that pivot carries out first kind of rotation, and this pivot is divided into a galianconism of representing lever " resistance " and one to lever and represents the long-armed of lever " power ", in long-armed end described container is installed; Comprise a device that makes described container fill dielectric fluid automatically on the other hand, this goes into by described opening when filling stuffing box, this device is loaded on the end of galianconism, be used for a power is put on exciter, when described power surpassed a threshold value by the predetermined resistance of exciter antagonism, described outage just took place; The relative size of lever arm and container dimensional are such arrangements, so that as long as the case of transformer is filled dielectric fluid, then container immerses in this fluid fully, and the power on the exciter of putting on is less than described predetermined threshold; If be considered to jeopardously low liquid level and the surface of described fluid drops to one, the described container that then keeps filling fluid reaches a kind of so emergent degree, so that under the effect of itself weight, the power that puts on the exciter can be above the threshold value of described predetermined trip.

The invention still further relates to a kind of immersion power transformer or distribution transformer, it is equipped with a self-shield equipment that comprises above-mentioned tripping mechanism.

Basic design of the present invention belongs to the sort of design that stuffing box intermediate current body fluid position is changed responsive lever tripping mechanism, it does not resemble the liquid level follower, be suspended in than the volume device on the long lever arm end (so-called " advantage (advantageous) " lever) and resemble, and be subjected to buoyancy function from this fluid.This volume device is empty at first, is full of by the dielectric fluid from stuffing box itself subsequently, so that can automatically finish this being full of when stuffing box is filled; This volume device is opened in a container for this reason, and this container is contained on the lever arm end.This container just remains after being full of and is full of; thereby have by the big total weight of buoyancy institute balance; after liquid level in stuffing box descends because of accident; it is poor that the emergent degree of flow surface causes producing a power in the stuffing box; its apparent total weight of this power official post is sent on the circuit breaker according to lever change ratio, and desired protection is implemented.

A key advantage according to tripping mechanism of the present invention belongs to the following fact: it attempts to satisfy in simple mode the constraint of obvious contradiction intrinsic in the lever buoyancy aid, so that buoyancy aid is inserted a little zone, buoyancy aid must only occupy as far as possible little space (in this case, this crowded part being placed on the following of transformer cover).Its reason is: perhaps use the suspension buoyancy aid, so that can shorten its lever arm of supporting, but in this case, it is too huge that buoyancy aid becomes, and just can float because it needs big volume; Perhaps use the buoyancy aid of smaller size smaller, itself become on the lever arm of heaviness, because it need extend the moment that could keep lever but need to put it to one in this case.What be worth emphasizing is; under the situation of the system that uses the self-protected transformer that disconnects a method of winding; this problem is especially often to occur; its reason is: the tripping force that is added on the exciter by lever resistance arm end is requirement very big (a 1kg magnitude); to avoid the protecting sensitivity of equipment too high, the too high meeting of sensitivity causes unnecessary accidental outage.

Description of drawings

Reference institute attaches pictures, and by following description, can more clearly understand the present invention, and other aspects and advantages of the present invention also can be clearer, in the accompanying drawings:

Fig. 1 with section form schematically illustrate before filling case with the dielectric cooling fluid the subway transformer case and according to equipment of the present invention;

Same cubicles and the identical device of Fig. 2 explanation when filling case;

Same cubicles and the identical device of Fig. 3 explanation after filling case; With

Fig. 4 explanation is occurring causing that the dielectric fluid that the liquid level of liquid described in the case jeopardously descends leaks later same cubicles and identical device.

Embodiment

In each figure, those only are described to the useful element of understanding the present invention, and have a mind to enlarge its size, so that explanation.Especially; basic electric parts wherein are not shown; they can be the parts of any kind known of those skilled in the art; equally, be not shown specifically the self-shield equipment unit except tripping mechanism yet: the complete description of these parts, can consult for example above-mentioned document EP 0 when needed; 653; 765, in this description, introduce its content, for reference.

In each figure, represent components identical with identical label.

Fig. 1 only schematically illustrates the conventional components of some self-shield subway transformers; it is the case 1 of transformer; the live part 19 that dots (wherein can discern three-phase transformer all phases three structures and put part); with power cut-off equipment 5; if a kind ofly can cause the unusual of transformer blast; for example the dielectric fluid liquid level descends singularly, and then equipment 5 is necessarily tripped.Case 1 with the sealing means sealing, is equipped with a hand-hole 4 by lid 3, and hole 4 allowed that the dielectric fluid perfect vacuum of case 1 usefulness mineral oil and so on filled before transformer is tried out first.This hand-hole itself is usually also by 18 sealings of a sealing plug.Before carrying out this initial fill operation, case 1 shown in Figure 1 is described earlier.

According to the present invention, in case 1, place a lever self-shield trip device, it comprises following elements:

-one lever of first order 6;

-one horizontal pivot 7, it is settled by following manner: it is divided into two arms that length is respectively " d " and " D " to this lever 6; D is corresponding to galianconism 8, constitutes " resistance " arm, and D constitutes " power " arm corresponding to long-armed 9.

-one container 10 is contained in long-armed 9 end, and it has one and freely injects opening 20, and the effect meeting of its weight the end at galianconism 8 produces a power that makes progress " F " according to the conversion ratio D/d of lever., only do not add the top dividing plate here, just can provide opening 20 on the top of container; With

-one push rod 11 on the end of galianconism 8, be used in operation power " F " being added to its exciter 2 of antagonism, resistive drag force " Fd " is equivalent to be used for the selected trip threshold of driver unit 5, so that disconnect a winding of transformer from power supply grid.

Whole assembly by tripping lever 6, exciter 2 and circuit breaker 5 form constitutes the built-in type self-shield equipment that the present invention relates to.

About tripping lever 6, it forms actual subject of the present invention, and the position of its size characteristic and its element is to determine that according to the criterion of having mentioned this also will illustrate below again.

Whole building blocks of self-shield equipment are all made by close material (metal or plastics), and they can be owing to the contact dielectric fluid changes at the whole planning period that uses transformer.In addition, also tripping lever 6 and end container 10 thereof are chosen to the material of a kind of its density less than dielectric fluid density, so that it is in a kind of stable " height " position, this as can be seen from Figure 3 situation naturally in the normal running of transformer.

When new transformer of assembling, there is not dielectric fluid in the case 1, lever 6 is vertical under its long-armed 9 side freedom, at this moment push rod 11 then acts on the power cutoff device 2 with a zero load (blank) power " Fo ", the unloaded weight that " Fo " is imagined as container 10 multiply by the conversion ratio of lever 6, it is less than threshold value " Fd ", if greater than " Fd ", then power cutoff device 2 necessarily trips.

This equipment also comprises a retainer 12, and its effect will illustrate below.

Fig. 2 illustrates the case 1 of the transformer when filling dielectric fluid 13.Extract this fluid out from holder 14, it is delivered in the case 1 by the pipe 15 that is connected in the hole of covering in 34.As shown in Figure 2, after the container 10 on long-armed 9 ends of the surface of fluid 13 arrival lever 6, this unloaded container can rise gradually owing to buoyancy function, floats on liquid level, runs into until it till the stop column 12 that is in " height " position.

Transformer tank 1 when Fig. 3 illustrates dielectric fluid 13 and is in normal volume in its case in this case, supposes that case 1 " fills fully or almost completely fill ".Under the whole circumstances, dielectric fluid surface 16 all is in a kind of final liquid level that makes container 10 complete submergences.As mentioned above, the upper limb of container 10 at first contacts retainer 12, and it can prevent that container from further rising, thereby makes container as long as the liquid level on surface 16 arrives the edge of container, just can inject opening 20 and automatically fill dielectric fluid by top.After container 10 is full of fully, its position is immersed in the fluid identical with its splendid attire fluid fully, thereby produce a power that makes push rod 11 preferably keep hindering a little exciter 2, and under the whole circumstances, the power on the exciter of acting on is all less than trip threshold " Fd ".

Fig. 4 illustrates transformer tank 1, and at this moment case 1 has accident perforation 17, and some dielectric fluids ooze out outside the case.This has caused case inner fluid 13 surperficial 16 liquid levels to descend gradually, thereby the buoyancy that causes acting on the container 10 takes place by corresponding reduction the as far as possible behindhand; Moderately keep exciter by the resistance " Fd " on the push rod 11 that acts on the galianconism end that begins to appear.

When container still is full of fluid 13, just there is the emergent degree of container on a dielectric fluid surface in case; Reach after the emergent degree, just be equivalent to the balance point between buoyancy and container 10 apparent weights.Surpass after this point, the power " F " that is acted on the exciter 2 by push rod 11 just begins to increase.When it reached and surpasses the selected value of exciter resistance " Fd " threshold value, the tripping mechanism of protection equipment just began operation.This situation can take place immediately, also can take place later at the pre-warning time that postpones a segment acknowledgement, moves one section short distance so that allow the trigger (not shown) that makes exciter 2 for this purpose.The relative size (determining its conversion ratio) of the position of calculating pivot 7 like this, the both arms of lever 6 and the capacity of container 10, so that the intensity of power " F " can become more much bigger than trip threshold " Fd ", and when the liquid level on dielectric fluid surface 16 has been reduced to the dangerous spot of meeting generation transformer blast, will surpass this threshold value " Fd ".Certainly, this liquid level must be scheduled to when the design transformer.

By a simple limiting examples, select a kind of polypropylene lever 6, its relative density is 0.9, total length is 330mm, distribute to length " the D "=300mm of long-armed 9 (lever moving arms), and distribute to length " the d "=30mm (being that conversion ratio is D/d=10) of galianconism 8 (resistance arm).Container 10 has weight and the 100cm of 20g ³Volume commonly used, but splendid attire 90g mineral oil.

Under these conditions, in container 10, do not have mineral oil, and when also not having oil in the case of contacting container 10, push rod 11 acts on the unloaded power " Fo " of a 200g on the exciter 2.In addition, tripping mechanism 6 can be set like this,, just disconnect transformer so that have only when the active force of push rod 11 surpasses the trip threshold " Fd " of a 800g.

When transformer was filled with oil, container 10 was in a kind of complete submerged state.If push rod 11 and exciter 2 are not in contact with one another, then the power that is acted on the exciter 2 by push rod 11 is zero; And under any circumstance all less than 200g, its reason is that the density of lever immerses the density of dielectric fluid wherein less than it to this power owing to help long-armed 9 different buoyancy of lever 6.

On the other hand, when oil level has been reduced to the point that is equivalent to state shown in Figure 4-container 10 of wherein filling dielectric fluid partly exposes, then a power that equals 90 * 10=900g that produces owing to the apparent weight of fluid 13 volumes in the container 10 just is added to one and is being affacted on the power of the 200g on the exciter by push rod 11 under the empty situation usually.Therefore and the driver transformer outage therefore, power " F " is 200+900=1100g, thereby far above the trip threshold " Fd " of 800g, and.Compare with relevant other power that at this moment works, it is less still partly being immersed in the influence that produces in the dielectric fluid owing to lever is long-armed, only influences second of the order of magnitude.

This equipment that is used to detect the dielectric fluid liquid level is all very simple in design, structure and the operation at it, from but very reliable.The risk that does not have mis-behave at any time.Another advantage that is better than conventional buoyancy aid equipment is, before filling transformer and in, buoyancy aid equipment makes the power cutoff device tripping operation.Therefore, necessary replacement power cutoff device after filling; Yet this is allowing on the structure that having this possibility is condition, otherwise will be provided for when filling the device at high-order locking buoyancy aid, and work can make the structure of trip device further complicated like this.

Self-evident, as to the invention is not restricted to describe with reference to the accompanying drawings example is if but be conceived to the qualification of the present invention that following claims provide, then can extend out many variations or equivalence example.

For example, retainer 12 can be made of well lid 13 bottoms own.In this case, on the edge of container 10, be preferably on the downside of lever, the one or more recesses that provide can advantageously constitute the passage that some are used for dielectric fluid 13, make dielectric fluid enter container when being in lid 3 adjoiners with convenient container.Equally, also can fulfil above-mentioned functions near opening some holes on the wall of container upper limb.

Too, container 10 can automatically not be full of dielectric fluid by its top yet.This is because might open a hole at container bottom fully, when being full of case, by this hole dielectric fluid is flowed into; Yet a check-valves will be placed in its bottom in this hole, in case internal tank is communicated in fluid dielectric on every side subsequently.

Therefore, more generally, must be designed to these devices to allow when filling case, make described container automatically fill dielectric fluid, in case this fluid is with after same route leaves container by its opening that enters.

Claims

1. one kind is used for the tripping mechanism that installing is equipped with in; when it descends unusually in contingency generation dielectric fluid liquid level; by disconnecting winding of transformer from power supply grid; automatically protect one to be immersed in one and to fill with the piezoelectric transformer (19) in the case (1) of dielectric cooling fluid; should interior installing comprise a circuit breaker (5) that is applied to it by an exciter (2) fully; and exciter (2) itself is encouraged by described tripping mechanism; this tripping mechanism comprises that has a container (10) that enters opening (20); this tripping mechanism is characterised in that it comprises a lever (6) that carries out first kind rotation around a pivot (7) on the one hand; pivot (7) is divided into a galianconism (8) and long-armed (9) of representing lever " power " of representing lever " resistance " to lever (6); described container (10) is equipped with in long-armed end; and comprise that on the other hand one is allowed that when case is filled described container automatically fills the device of dielectric fluid by described opening (20); this device is contained in the end of galianconism (8); be used for exciter (2) is applied a power; when described power during greater than a predetermined trip threshold value by exciter antagonism; described outage just takes place; lever arm (8; the relative size of relative size 9) and container (10) is such; so that as long as case is filled dielectric fluid (13); container just is immersed in this dielectric fluid fully; with the power on the exciter of being added to less than described predetermined threshold; if and the surface of described dielectric fluid (16) drop to one and are considered to jeopardously low liquid level; the described container of then still filling dielectric fluid (13) arrives an emergent like this degree; so that under the effect of its weight, the power that is added on the exciter surpasses described predetermined trip threshold value.

2. according to the tripping mechanism of claim 1, it is characterized in that the container (10) that is contained in lever long-armed (9) end is (20) opening at an upper portion thereof.

3. according to the tripping mechanism of claim 1 or 2, it is characterized in that, allow that (10 automatically fill the device of dielectric fluid to container by described opening (20) when filling case, comprise a retainer that engages with described container edge (12).

4. according to the tripping mechanism of claim 1 or 2, it is characterized in that, allow that container (10) automatically fills the device of dielectric fluid by described opening (20) when filling case, comprise that some are located at the groove of described container edge.

5. according to the tripping mechanism of claim 1, it is characterized in that, container (10) be equipped with one form in its bottom enter opening; Allow that described container automatically fills the device of dielectric fluid by described opening, comprise a check-valves that cooperatively interacts with described opening.

6. immersion power transformer or distribution transformer; it comprises a built-in type Self-Protection Subsystem (6; 2; 5); when liquid level (16) contingency of the dielectric fluid (13) of this system in the case (1) of splendid attire dielectric fluid takes place to descend; operate by disconnecting electric power network, described system comprises one to the responsive tripping mechanism of described liquid level variation, it is characterized in that described tripping mechanism (6) is consistent with the tripping mechanism in the claim 1.