CN1110000A

CN1110000A - Electrical switching device

Info

Publication number: CN1110000A
Application number: CN94118865A
Authority: CN
Inventors: P·西波尔迪; J·E·达尔德; E·杜尔尼; G·毛特赫; L·尼迈耶; S·O·奥尔森; F·佩东兴; R·施特卢姆普勒
Original assignee: ABB Patent GmbH
Current assignee: ABB Patent GmbH
Priority date: 1993-11-30
Filing date: 1994-11-29
Publication date: 1995-10-11
Also published as: DK0655760T3; EP0655760B1; JPH087721A; DE59409050D1; EP0655760A2; EP0655760A3; DE4340632A1; ES2143518T3

Abstract

A switching device which can be used in at least one mains conductor of a medium-voltage or high-voltage power supply network interrupts the at least one mains conductor if a specific overcurrent occurs. In order to simplify and reduce the price of the switching device, a non-linear resistor having a positive temperature coefficient is connected in series with an electrical load interrupter switch, which resistor limits the overcurrent which occurs to current levels which can be switched by the load interrupter switch. A short-circuit current can be switched by assigning a load interrupter switch to a non-linear resistor.

Description

Electrical switching device

The present invention relates to a kind of electric switchgear.

In the medium and high pressure scope, utilize switching device opens overcurrent or short circuit current, this switching device is called power circuit breaker again, comprises the SF that is used for high pressure ₆Vacuum switch and low-oil-content circuit-breaker that power circuit breaker or be used for is pressed, or be similar to SF ₆The switch of circuit breaker.

The purpose of this invention is to provide a kind of this paper and start described switching device, it can save manufacturing cost, but still has the same capacity that cut-offs.

Material and combined material that the present invention adopts are the specific materials as describing among the patent specification P4221309, and the temperature of these materials and resistance increase along with electric current and raises.If this nonlinear resistance and switching device are connected in series, when short circuit current or common overcurrent occurring, this electric current is restricted, and makes short circuit current or overcurrent not reach the destructiveness of expection.Therefore, needn't install a circuit breaker for blocking short dot specially, get final product and isolating switch or load-break switch only need be installed, this switch can interdict aftercurrent or rated current in special time.Described nonlinear resistance is connected on isolating switch or the load-break switch, then can saves the cost of short switch device significantly, isolating switch or on-load switch can be made the quick acting isolating switch with special purpose; If nonlinear resistance can continue the withstand voltage long period, also there is the possibility of a kind of reducing cost (not talkative inexpensive), can use isolating switch at a slow speed, its effect is to bear voltage in the disjunction position.

An impedance and this nonlinear resistance can be connected in parallel, this impedance can be linear or nonlinear, that is to say with change in voltage.A for example available capacitor utilizes discharging and recharging of capacitor to reduce the due to voltage spikes value.An also available resistor, preferably rheostat replaces capacitor, and this impedance can constitute an integral body with described nonlinear resistance, also separable formation, but for the electrical network with high inductance, this impedance must be in parallel with nonlinear resistance.

Adopt another superiority of this nonlinear resistor to embody: when the electric current that flows through in the power circuit changes, can utilize checkout gear to measure the variation of resistance characteristic, so this device can produce a signal when overcurrent takes place, this signal passes in the operating mechanism of isolating switch or on-load switch then.

In this case, people have utilized the variation that overcurrent non-linear hour resistance characteristic occurs to reflect this objective fact.On the one hand, because the resistance of nonlinear resistance increases the variation that causes the voltage that obtains on it, this change in voltage can be detected and be handled.

On the other hand, overall dimension and temperature that overcurrent non-linear hour resistance occurs all change, and the change of the variation of this size, especially volume or length can be used for causing interrupt operation.

In addition, also can in resistor, dispose temperature-measuring element, when temperature rises, can produce a corresponding signal.

In addition, can with this resistor actuated element that is connected in parallel, for example a kind of piezoelectric device, when the voltage on the resistor raise, this actuated element the voltage that is provided can be provided and produce length variations or bending.This length variations or crooked signal can be used to the operating operation device to be used to drive the rupturing operation of load-break switch.

The present invention further optimization scheme promptly also can install a switching mechanism with a keyed end additional to nonlinear resistance or resistance device, and this switching mechanism is used for installation switching device.In this case, can adopt slide unit, be mounted on the switching mechanism, this slide unit is preferably made pin or sleeve, the operating mechanism or the direct control switch that are used for driving switch, also can be equipped with an electromagnetic release unit on nonlinear resistor, this electromagnetic release unit is used for the switching mechanism release.

In this case, the lead as an electromagnetic release unit part can be connected on the electrode of nonlinear resistance.

In another preferred embodiment of the present invention, nonlinear resistance can keep together by the bracing or strutting arrangement made from insulating material with switching mechanism and/or relieving mechanism and/or lead and/or locking device.This bracing or strutting arrangement can be a shell that the insulating material that accommodates nonlinear resistance in it is at least made, and this shell directly envelopes this nonlinear resistance tightly, and discharges and/or switching mechanism can be arranged in the enclosure the free space.

According to the present invention, this shell can be made tubulose, cylinder-like structure preferably, and its end can be added a cover, and is used to connect power line or output.

Simultaneously, the resistance value of insulating material that is used for bracing or strutting arrangement (preferably shell) is preferably with change in voltage, and for example voltage-sensitive ceramic can absorb local overvoltage like this.Certainly this bracing or strutting arrangement also can have at least one by pillar made of insulating material, and nonlinear resistor and switching mechanism and/or release and/or the common unit of formation of conductor or this pillar pass the center of nonlinear resistance.

According to the present invention, slide unit is preferably made pin, and it can bear the pressure of spring, therefore can change the unlocked position of locking point, promptly jumps out this shell.

According to the present invention, this switching mechanism has a spring driven locking device, and spring is fixed a pin, and when flowing through rated current, pin is by spring force effect work, and when overcurrent took place, this locking device discharged.Spring can be made by thermoelectric bimetallic material or shape memory metal.

A kind of fuse also can be used as locking device, and it fixes the power that this slide unit withstands spring, in case overcurrent occurs, this fuse melting, the power of retracting spring simultaneously.Certainly also an end of slide unit can be fixed in the sleeve, medicament contained stage clip and fuse, and a contact projection is housed at the other end of sleeve, when it can form contact with the contact that another and nonlinear resistance are electrically connected, if fuse failure, and slide unit is jumped out, locking discharges, the on-load switch operation only needs after the switch motion that slide unit, stage clip and fuse are inserted new sleeve and gets final product, and it is very easy therefore more to change jobs.

Other improvements of the present invention are embodied in the theme of remaining dependent claims.

Further describe and explain the present invention and improvement of the present invention with reference to the accompanying drawings and improve part, and advantage of the present invention, comprising illustrated several embodiments of the invention, accompanying drawing is:

Fig. 1 represents to be inserted with the electrical network circuit diagram of nonlinear resistance;

Fig. 2 represents to connect with the electrical network circuit of single-phase transmission line representative;

Fig. 3 represents the structure of nonlinear resistor;

Fig. 4 represents that the circuit of using the representation identical with Fig. 2 and having nonlinear resistance connects;

Fig. 5 represents to be connected to the circuit of nonlinear resistance and fuse;

Fig. 6 represents to operate the device of releasing device, and it has the nonlinear resistance of an integral body;

Another embodiment of Fig. 7 presentation graphs 6 devices;

The zoomed-in view of Fig. 8 presentation graphs 7 subregions;

Fig. 9 represents to have further embodiment of this invention of nonlinear resistance;

The zoomed-in view of Figure 10 presentation graphs 9 equipment regional areas.

In medium voltage network shown in Figure 1, three phase mains R, S, T are connected on the exit of transformer 10, from high-voltage fence R1, and S1, the voltage of T1 becomes middle pressure through this transformer.

PTC(positive temperature coefficient as nonlinear resistance)

thermistor

11,12 and 13 is connected on three-phase conducting wire R, S, on each of T, these PTC thermistors have nonlinear impedance (11a, 12a, 13a), isolating switch 14 has the lead of being connected on R, S, the

contact

15,16 among the T, 17, with dashed lines illustrates among the isolating switch 14(figure) also comprise a switch operating mechanism 18, it is by feeder line 19,20,21 are connected to relieving

mechanism

23,24,25, these feeder lines 19,20,21 all are connected on the common wire 22.

Relieving mechanism

23,24,25 are connected on

PTC thermistor

11,12 and 13, are used to detect PTC thermistor 11, the variation of 12 and 13 characteristics, and according to the variation of being surveyed via circuit 19,20,21 transmit, operating mechanism 18 is moved by these signal excitation, and

contact

15,16,17 is disconnected.When flowing through lead R, S, when the electric current of T increases,

PTC thermistor

11,12 and 13 temperature change, its resistance value also changes, thereby has limited the

contact

15,16 of flowing through isolating

switch

14 and 17 electric current.Here can adopt various detection parts to survey the variation of

PTC thermistor

11,12 and 13 features.

In the circuit connecting mode of Fig. 2, be used to detect the device 31 that PTC thermistor both end voltage changes and be connected in parallel with PTC thermistor 30, the output signal of device 31 is sent into relieving mechanism or operating mechanism 18 via circuit 32.

Relieving mechanism

23,24,25 also can be omitted, and with

PTC thermistor

11,12,13 are contained in the operating equipment.Therefore in the embodiments of figure 3, ptc material 34 is placed in the shell 35,36 sealings of lid of making of the bottom of this shell by electric conducting material, leave a free space 38 between the upper end of ptc material 34 and upper cover 37, the effect in this space is to be that the elongation of ptc material 34 on length provided convenience when taking place that over-current phenomenon avoidance causes temperature to rise.In order to detect the variation on this length, 39, articulated linkage 40 of plate of an electric conducting material of configuration are connected on this piece plate 39 connecting rod Mechanical Driven operating mechanism 18 actions thus on ptc material free-ended.Shell 35 is made by insulating material, and power lead 41 or output lead 42 are connected on lid 36 or the plate 39, the circuit of Fig. 3 can be received on the power supply R by these leads.Linkage 40 the most handy nonconductive material become, and the conductor 42 that is connected with plate 39 passes 38 backs, space and stretched out by opening 43, and connecting rod 40 is connected with plate 39 by hole 44.If without shell, the supporting rod at also available break-through PTC thermistor center replaces, and the material of shell or supporting rod is an insulating material, and it can have nonlinear, with the resistance value of change in voltage, for example adopts ceramic varistor.

In the structure of Fig. 3, utilize device 23 to detect the variation of ptc material 11 characteristics, it and PTC thermistor are combined into one, and the mode of operation of linkage 40 is corresponding with lead-in wire 19/22.

In the embodiment of Fig. 4, PTC thermistor 50 for example is connected on the power circuit R, voltage signal is sent in the actuator 53 of being made by piezoelectric device by circuit 52 with the voltage measuring apparatus 51 that resistance is connected in parallel.This voltage signal causes the change that piezoelectric device 53 produces on the length, and this length variations can be ordered about contact 15 and be opened by connecting rod 54 feed-in operating mechanisms 18.Except can utilizing the piezoelectric device 53 that length changes, also can use the piezoelectric device that produces bending change, the piezoelectric that can Gong select for use is a lot, for example is disclosed in 190163 PA 2818 in Siemens's document " Vibrit ", and serial number is N-281/5053.

Fig. 5 represents another different scheme.PTC thermistor 60 is received on the circuit R, and an insurance 61 is in parallel with it, and insurance 61 itself is known, and it has an overcoat 62, and an end of overcoat is by a contact cap 63 sealings, and the other end is sealed by contact cap 64.In contact cap 64, change a conduit 65 over to, in conduit 65, fill in a pin 66.Fuse 67 is between pin 66 and following contact cap 63, and pin 66 relies on spring to eject to the arrow A direction, and spring is not shown in Fig. 5, and

block

63 and 64 is connected to respectively on the bus R through lead-out

wire

67 and 68, is parallel to the PTC thermistor thereby will insure 61.If overcurrent, the resistance of ptc material will rise a lot, force the electric current major part to flow through via insurance.So fuse 67 fusing, pin 66 move to the 66a of position shown in the dotted line among the figure by the arrow A direction.This action excitation operating mechanism 18 actions of pin 66 are so disconnect load-break switch 14.

Also available better simply safeties, this insurance only needs withstand voltage, need not conduct rated current.Its designing requirement is to conduct less nominal current.

Another embodiment of the present invention is illustrated among Fig. 6.PTC thermistor 71 is contained in the insulation crust 70.In Fig. 6, the lower end of shell 70 is sealed with the cap 72 of electric conducting material, and this cap is bowl-type, has the outer rim 73 in the L shaped cross section on button limit, relies on these outer rims that the cap body is enclosed on the lower end of shell 70.Electric conductor 41 is connected on the cap body 72.There is a segment distance upper end of the upper end of ptc material and shell 70, and the upper end of shell is by 74 sealings of cap body, and this cap body is fully identical with cap body 72.In the upper end of ptc material is a conductive layer 75, and it links to each other with a conducting rod 76 that passes from electromagnetic system 77.The upper end of conducting rod 76 then is connected electrically on the cap body 74.Switching mechanism 78 in the free space between loam cake 75 and cap body 74 has a trip lever 79, and it matches with locking cam 80 on the pin 81.Work as electromagnetic system, effect by magnetic armature 82 is moved, turn to along clockwise direction in the switching mechanism 78 under the unshowned in the drawings spring of trip lever 79, in case (not shown) locking cam 80 discharges under the pressure effect of spring, selling 81 moves towards direction of arrow A, results operation mechanism 18 situation action as shown in Figure 5 disconnects switch.This operating mechanism then no longer needs the double as blocking mechanism.

Fig. 7 shows a kind of similar structures.Ptc material 88 is positioned at shell 85 inside, and shell is made by insulating material, and its bottom and top are respectively by

cap body

86 and 87 sealings.The ptc material center has a perforate 89, it is round a conductor 90, and this conductor slightly exceeds the plane of ptc material 88 at one end (being the upper end in this figure), and its other end is that the lower end has a plate 89a, this plate fixedly installs on the conductor 90 by nut, is electrically connected with ptc material 88 simultaneously.A U-shaped contact 91 is contained on the free end (being positioned at the figure middle and upper part) of conductor 90, and chimeric with contact pin 92.

With reference now to Fig. 8,, this is a partial enlarged drawing.

Contact 91 has two

pins

93 and 94, and they and pin 92 are chimeric.Pin 92 is integrally formed on the rotating parts 95 that is fixed in the sheath 96, and sheath 96 is made by insulating material, and its end is towards conductor spare 90, and can screw in it; Pin 92 stretches out sheath 96 from opening 97.The upper end of sheath 96 is fixed at the bottom of block 87 the cap by flange 91a on 99 the embedding wheel rim 98, the inner sheath of being made by metal material 100 is enclosed within telescope sheath 96, inner sheath opens wide in the bottom of sheath 96, and seals in the zone of 87 the bottom 99 of blocking a shot.The end of inner sheath and rotating parts 95 have a segment distance, to avoid being electrically connected between this end and rotating parts.The oversheath of being made by insulating material 96 has the transverse opening (not shown) in ring flange 91a scope, the contact spring (not shown) passes this opening and is integrally formed on the inner sheath that is entrenched at the bottom of the cap 99 wheel rim 98 outsides.Inner sheath 100 is slide units, accommodates a compression spring 101, and an end of spring is supported on the rotating parts 95, and the other end of spring is supported on the last blind end of inner sheath 100.Stage clip 101 by insulating material around, therefore can not have any electric current to flow through this stage clip 101.Fuse 103 is contained between the upper end and rotating parts 95 of inner sheath and/or contact 102.Provide thus one by contact component 91 to parts 92/95 with to the fixing electric path of an end of fuse 103; Its other end is by contact 102, and inner sheath 100 and its touch spring and contact with wheel rim 98, and this touches spring and radially outward acts on by oversheath.When overcurrent occurred, fuse 103 melted, and the pressure that 100 of inner sheaths are subjected to stage clip 101 ejects to outer direction of arrow A, and its mode is the same with pin 81 among Fig. 5 embodiment.If fuse 103 has fused, only need take away sheath 96, replace

sheath

100 and 96 with new sheath.Can on sheath 96, install a handle additional, so that take out and change sheath.

In the embodiment of Figure 10, do not adorn fuse.Guide rod 111 usefulness screws that make with insulating material and that exceed the upper end of PTC thermistor 88 are screwed on the conductor spare 110, and this conductor spare is screwed in the ptc material 88.Guide rod 111 is positioned at the zone of upper end cap 87, be pressed in the guide bracket 112 that is in oversheath 113 lower ends, oversheath 113 has a ring flange on inner end 114, inner end is positioned at guide bracket 112 inside, stage clip 115 is supported on this ring flange 114, and the other end of spring supports on the upper end 116 of inner sheath 117 of inside crimping.Inner sheath is connected on the bar 118 by this ring flange 116.This bar 118 inserts guide bracket 112 and directly reaches near the free end of conductor spare 110, and a spring 119 is housed on the conductor spare, and this spring 119 is a U-shaped, have two legs 120 and 121, they curve inwardly, and approximately V-shaped at its free end, thereby form a necking down 122.The mushroom-shaped of bar 118 inner 123 embeds in this necking down 122, and relies on spring part 119 to withstand the pressure of spring 115 securely.When electric current increased, temperature also increased, and made spring part 119 distortion, two pin ones 20 and 121 of spring element 119 open, release lever 118, so bar 118 moves towards outer direction of arrow A under the active force of spring 115, This move drives switch operating mechanism 18 actions.Spring part 119 can be made by thermoelectric bimetallic material or marmem.

Outer sleeve

70 or 85 among Fig. 6 to 10 is made by insulating material, can recommend to adopt pottery to become the resistance material here.Adopting pottery to become the reason that hinders material can be referring to German patent specification recited above.

In the structure of Fig. 7-10,88 be electrically connected by a litzendraht wire 130 and realize from lower endcaps 86 to ptc material; Another root braided wire 131 is connected to upper end cap 87 with the upper end of ptc material; So current path is formed up to end cap 87 by conductor spare 90 and fuse 103 and/or conductor spare 110 and sheath 111 and/or spring part 119 and bar 118.Can obtain the parallel branch of ptc material 88, fuse 103 and/or spring element 119.

In the structure of Fig. 7 and 8 or 9 and 10, fuse needs the conduction one part of current with 119 of the U-shaped spring parts that has guide rod 118.Under the embodiment of Fig. 9 and 10 situation, guide rod 118 need be pressed into again, and this can realize by manual operation or straighforward operation.Under the embodiment of Fig. 7 and 8 situation, need to change the insurance device, comprise sheath 96, inner sheath 100, fuse 103 and pressing spring 101.Because these assemblies only flow through the fraction electric current, and most of electric current is flow through by PTC thermistor and braided

wire

130 and 131, therefore the manufacturing cost of this fuse can be reduced.If the device of Fig. 7 and 8 moves, the Arming Assembly that need more renew only.

Inner sheath can be made into the slide unit of pull switch device operation, or makes the slide unit of releasing operation device, also Lock mechanism effect of this operating means itself.

Claims

1, electric switchgear, it can insert at least one phase power line of electrical network, and when overcurrent occurring, cut off at least one phase power line, nonlinear resistor and electric switch are connected in series, the resistance of this resistor presents non-linear increase with the electric current increase, this nonlinear resistor preferably has positive temperature coefficient, it is characterized in that, this electric switch is a kind of isolating switch or load-break switch, linearity or non-linear with change in voltage impedance as rheostat and as described in nonlinear resistor be connected in parallel.

2, according to the switching device of claim 1, it is characterized in that comprising checkout gear, when electric current in the power network line changes, checkout gear is measured the variation of nonlinear resistor characteristic, if overcurrent, this device produces corresponding signal, and is sent to the operating mechanism of switching device, promptly when producing, signal makes the operating mechanism action, the cut-off switch device.

3,, it is characterized in that described device detects the variation of voltage on the nonlinear resistor according to the switching device of claim 2.

According to the switching device of claim 2, it is characterized in that 4, described device detects the variation on the nonlinear resistor physical dimension.

According to the switching device of claim 2, it is characterized in that 5, this device detects the nonlinear resistor variation of temperature.

6, according to the switching device of one of claim 1-5, it is characterized in that, the device that is used to detect the change in voltage of nonlinear resistor is formed by an actuator that is connected in parallel with nonlinear resistor, this mechanism is piezoelectric part preferably, according to its variation of geometry, the action of the operating mechanism of energizing switch device.

7, according to the switching device of one of claim 1-6, it is characterized in that switching mechanism has a locking point for the nonlinear resistance configuration, utilize this locking point, when overcurrent occurring, switching mechanism can make isolating switch or load break switch move and release is put in locking.

8, according to the switching device of claim 7, it is characterized in that switching mechanism has a slide unit, when the locking point of switching mechanism discharges, the operating mechanism action of this slide unit excitation isolating switch or load-break switch.

9,, it is characterized in that relieving mechanism of nonlinear resistor configuration, this relieving mechanism console switch mechanism according to the switching device of claim 7 or 8.

10, according to the switching device of claim 9, it is characterized in that this relieving mechanism is a kind of electromagnetic release unit with armature, be used for the locking point of driving switch mechanism.

11,, it is characterized in that a part of conductor of electromagnetism release is connected on the electrode of nonlinear resistor according to the switching device of one of claim 9 and 10.

12,, it is characterized in that nonlinear resistor and switching mechanism and/or release and/or conductor together support are on the strutting piece that insulating material is made according to the switching device of one of claim 7-11.

13, according to the switching device of claim 12, it is characterized in that this strutting piece has at least one by pillar made of insulating material, and nonlinear resistor and switching mechanism and/or release and/or unit of the common formation of conductor.

14,, it is characterized in that this pillar passes the center of nonlinear resistance according to the switching device of claim 13.

According to the switching device of claim 12, it is characterized in that 15, described strutting piece is a cavity or outer sleeve, nonlinear resistor is housed in it at least.

16,, it is characterized in that release and/or switching mechanism are configured in the interior free space of outer sleeve according to the switching device of claim 15.

According to the switching device of claim 16, it is characterized in that 17, this outer sleeve is tubular, preferably cylindrical, in its end the cap body is arranged, on the cap body, be connected with and introduce or lead-out wire, nonlinear resistor is connected electrically on the end cap cap body.

18, according to the switching device of one of claim 12-17, it is characterized in that described insulating material has the nonlinear resistance value, promptly when overcurrent occurring, the non-linear resistance of this material changes.

According to the switching device of one of claim 11-13, it is characterized in that 19, this insulating material is to become the resistance pottery.

20, according to Claim 8 one of switching device is characterized in that-19, and this slide unit is a pin, can eject strutting piece under acting force of the spring, is outer sleeve specifically.

21, according to the switching device of one of claim 15-20, it is characterized in that, this nonlinear resistor only partly occupies the interior space of outer sleeve, and switching mechanism and/or conductor and/or the electromagnetic system that has armature all are contained between the free end of nonlinear resistor and adjacent conductive.

According to the switching device of one of aforementioned claim, it is characterized in that 22, switching mechanism has a blocking mechanism, by case spring slide unit is fixed, this slide unit bears the pressure of spring, preferably adopts the pin form, and is released when overcurrent occurring.

23, according to the switching device of claim 17, it is characterized in that described case spring spare is a U-shaped, the taper pin of shape variable (thermoelectric bimetallic material or marmem) when having variations in temperature, the mushroom-shaped zone of pin rod the inner is clamped in taper in the back, thereby secures the above pin rod.

24, according to the switching device of one of claim 1-21, it is characterized in that adopting fuse as blocking mechanism, fuse fixedly slide unit withstands the active force of spring, and when overcurrent occurring, fuse melts, and spring force forces slide unit outwards to move.

According to the switching device of claim 24, it is characterized in that 25, slide unit and compression spring and fuse are arranged in the sheath, have a contact projection on the inner of sheath, it cooperates with the electrical contact that another and nonlinear resistor are electrically connected.

According to the switching device of claim 24 and 25, it is characterized in that 26, slide unit is made of an inner sheath, its end sealing outwardly, an end inwardly opens wide, and introduces in the sheath, accommodates fuse and stage clip in the inner sheath.

According to the switching device of one of aforementioned claim, it is characterized in that 27, nonlinear resistance is contained in the main current path, and fuse or U-shaped spring part are contained on the parallel with it current bypass.