A protection device and circuit for electrical engineering distribution transformer

Abstract

The application discloses a kind of protection device and circuit of electrical engineering distribution transformer, protection device includes protection seat, buckle part, protection seat has the conducting strip installation structure of open circuit state, buckle part has power supply and protection mechanism;Buckle part is buckled to protection seat, the circuit of open circuit conducting strip installation structure can be conducted, and the circuit of conduction passes through protection mechanism;Protection mechanism includes conducting rod telescopic component, fuse component.Conducting rod telescopic component can be contacted with one of conducting strip after being inserted into protection seat;Fuse component is tightly connected and electrically connected conducting rod telescopic component to make conducting rod telescopic component into protection seat, and this fuse component has overcurrent fuse and then length shortening structure.Light and sound alarm device is provided in protection seat.The application uses 2 level protection structure to protect transformer, one is installed protection device in distribution box, the fuse of protection device will be fused after overcurrent, to make passage disconnected.Two are set in distribution box Protection circuit, as secondary protection.

Description

TECHNICAL FIELD

[0001] The present application relates to a transformer, in particular to a protection device and circuit for electrical engineering distribution transformer. BACKGROUND

[0002] The transformer is a device for changing AC voltage by using the principle of electromagnetic induction, and the main components are primary coil, secondary coil and core. According to the use, it can be divided into: distribution transformer, combined transformer, dry-type transformer and oil-immersed transformer, etc. The transformer is one of the most critical devices in national economy and life, especially the oil-immersed transformer, because it bears the task of power transmission and transformation in a wide range, so its safety and normal operation is particularly important.

[0003] In the prior art, when the transformer encounters insulation failure and the internal pressure increases, a pressure relief valve is usually used for pressure relief. It has been proved by practice that the pressure relief valve can play a role in the normal pressure rise and fall of the transformer. When a violent electric arc occurs, the internal pressure of the transformer rises very quickly. At this time, due to the inherent mechanical properties of the pressure relief valve, it cannot release the pressure in time, thereby causing the explosion of the transformer. Analysis of the exploded transformer shows that these transformers are all installed with the above-mentioned pressure relief valve, but the explosion still occurs, which shows that the installation of the pressure relief valve cannot prevent the explosion of the transformer.

[0004] Therefore, it is necessary to install a protection device on the power supply control box of the distribution transformer to solve the above technical problems. SUMMARY

[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the present application is to provide a protection device and circuit for electrical engineering distribution transformer. The purpose of designing the protection device is to prevent the damage of the transformer caused by excessive current.

[0006] To solve the above technical problems, the present application realizes the following scheme: a protection device for electrical engineering distribution transformer, comprising a detachable protection seat and a buckle part, the protection seat has a circuit-breaking conductive strip installation structure, and the buckle part has a power supply and a protection mechanism;

[0007] After the buckle part buckles the protection seat, the circuit of the circuit-breaking conductive strip installation structure can be conducted, and the conducted circuit passes through the protection mechanism;

[0008] The protection mechanism comprises:

[0009] The conductive rod telescopic assembly can be telescoped into the protection seat and contacted with one of the conductive strips after being telescoped into the protection seat.

[0010] A fuse assembly abutting and electrically connecting the electrically-conductive rod telescopic assembly to make the electrically-conductive rod telescopic assembly extend into the protective seat, the fuse assembly having an overcurrent fuse and a length-reducing structure;

[0011] The protective seat is provided with an audible and visual alarm device;

[0012] The buckle part further has an on-off mechanism capable of conducting the audible and visual alarm device, the on-off mechanism comprising:

[0013] A passive switch is provided in the buckle part, the passive switch being in electrical contact with the audible and visual alarm device and capable of controlling the on-off of the audible and visual alarm device after the buckle part is inserted into the protective seat, the passive switch being electrically connected with a power supply;

[0014] A pressure head is fixed to the electrically-conductive rod telescopic assembly, the pressure head being capable of turning off the passive switch after being pressed down and automatically turning on the passive switch after being lifted up.

[0015] Further, the protective seat is a U-shaped structural member, having a U-shaped cavity inside, the bottom surface of the U-shaped opening of the protective seat being provided with four through holes, the four through holes being a first through hole, a second through hole, a third through hole and a fourth through hole respectively;

[0016] The electrically-conductive strip installation structure in the open circuit state comprises:

[0017] A left electrically-conductive strip, one end of which is fixed to the left cavity of the U-shaped cavity and the other end of which extends directly below the first through hole;

[0018] A right electrically-conductive strip, one end of which is fixed to the right cavity of the U-shaped cavity and the other end of which extends directly below the second through hole.

[0019] Further, the buckle part comprises:

[0020] A buckle shell having a battery slot, a straight cavity and an end hole, the first end of the straight cavity being opposite to the second through hole, the second end of the straight cavity being in communication with an end hole, the side part of the straight cavity being provided with a side opening, and the power supply being a rechargeable battery installed in the battery slot;

[0021] A first elastic electrode provided in the side opening, the round end of the first elastic electrode being capable of being extended, the round end being in the region of the straight cavity;

[0022] A first terminal protruding and fixed to the insertion end of the buckle shell, the first terminal being electrically connected with the first elastic electrode, the first terminal passing through the first through hole and being in contact with the left electrically-conductive strip after the buckle part is inserted into the protective seat.

[0023] Further, the conductive rod telescopic assembly comprises a conductive rod, a first compression spring, the thick section of the conductive rod is in the straight cavity, the thin section of the conductive rod extends to the second through hole, the first compression spring is sleeved on the thin section, one end of the first compression spring abuts against the edge of the second through hole, the other end of the first compression spring abuts against the step between the thick section and the thin section.

[0024] The lower end of the conductive rod contacts the right conductive strip after the conductive rod is abutted by the fuse assembly.

[0025] The pressure head is an insulating pressure head, and the insulating pressure head is fixed on one side of the conductive rod.

[0026] Further, a blocking plate limiting the upward distance of the pressure head is arranged on one side of the straight cavity.

[0027] Further, the fuse assembly comprises:

[0028] A lower pole, one end of the lower pole is a flat end, the flat end forms an abutting electrical connection with the conductive rod, the other end of the lower pole is provided with an annular stop ring, and the bottom surface of the annular stop ring is provided with a first jack arranged in an array.

[0029] An upper pole, the upper pole is provided with a second jack arranged in an array on the first surface opposite to the lower pole, and the first elastic electrode contacts the upper pole after the fuse assembly is positioned.

[0030] A plurality of fuses, the first end pin of the fuse is inserted into the first jack, and the second end pin of the fuse is inserted into the second jack.

[0031] An insulating part fixed on the second surface of the upper pole.

[0032] Further, an insulating cover is screwed on the end hole.

[0033] Further, the fuse further comprises a resistance wire assembly.

[0034] The resistance wire assembly comprises:

[0035] A glass rod, two ends of the glass rod are connected with the first end pin and the second end pin respectively, and the glass rod has a containing cavity in the interior.

[0036] A resistance wire, the resistance wire is arranged in the containing cavity, and two ends of the resistance wire are connected with the first end pin and the second end pin respectively.

[0037] An easily-expandable liquid, the easily-expandable liquid is filled in the containing cavity.

[0038] Further, the acousto-optic alarm device is fixed on the bottom cavity of the U-shaped cavity, and the shell top of the acousto-optic alarm device is provided with two power supply terminals opposite to the third through hole and the fourth through hole respectively.

[0039] The passive switch comprises:

[0040] An insulating support is fixed in the buckle part, and a contact terminal connected with the positive pole of the power supply and a spring post cavity are arranged on the insulating support;

[0041] Two electric pins are fixed on the insulating support, the two electric pins can respectively enter the third through hole and the fourth through hole and contact with the two power supply terminals one by one, and one of the first electric pins is electrically connected to the negative pole of the power supply;

[0042] A second elastic electrode is fixed in the insulating support, the non-elastic end of the second elastic electrode is electrically connected to the second electric pin, and the elastic end of the second elastic electrode is opposite to the contact terminal;

[0043] A second compression spring is arranged in the spring post cavity;

[0044] A hard terminal, the first end of the hard terminal is fixed to the upper end of the second compression spring, and the second end of the hard terminal extends to the upper end of the elastic end and is below the contact terminal;

[0045] A pressing key is fixed with the first end of the hard terminal, and the outer end of the pressing key extends out of the insulating support and is opposite to the pressing head.

[0046] The circuit of the application is applied to the electrical engineering distribution transformer, and the circuit comprises an audible and light alarm circuit and a secondary protection circuit;

[0047] The audible and light alarm circuit comprises:

[0048] A loudspeaker BZ1, the positive pole of which is connected with the hard terminal;

[0049] A triode Q24, the collector of which is connected with the negative pole of the loudspeaker BZ1, and the emitter of which is connected with the ground SGND;

[0050] A resistor R156, the first end of which is connected with the negative pole of the power supply, and the second end of which is connected with the base of the triode Q24;

[0051] A resistor R157, the first end of which is connected with the base of the triode Q24, and the second end of which is connected with the emitter of the triode Q24;

[0052] A triode Q25, the emitter of which is connected with the emitter of the triode Q24;

[0053] A resistor R160, the first end of which is connected with the emitter of the triode Q25, and the second end of which is connected with the base of the triode Q25;

[0054] A resistor R159, the first end of which is connected with the base of the triode Q25, and the second end of which is connected with the negative pole of the loudspeaker BZ1;

[0055] a diode D35 connected in parallel with the loudspeaker BZ1, wherein the negative pole of the diode D35 is connected to the negative pole of the loudspeaker BZ1;

[0056] a resistor R161, the first end of which is connected to the positive pole of the loudspeaker BZ1;

[0057] a light emitting diode LED1, the negative pole of which is connected to the collector of the triode Q25, and the positive pole of which is connected to the second end of the resistor R161;

[0058] The secondary protection circuit comprises an output current overload protection circuit and an output short circuit protection circuit;

[0059] The output current overload protection circuit comprises:

[0060] a resistor R132 and a capacitor C61, the first end of the resistor R132 being connected to the CT+ pin of the processor, the first end of the capacitor C61 being connected to the second end of the resistor R132, and the second end of the capacitor C61 being connected to the ground SGND;

[0061] a capacitor C64 connected in parallel with the capacitor C61;

[0062] a capacitor C62, a capacitor C65 and a capacitor C63, the first ends of the capacitor C62, the capacitor C65 and the capacitor C63 being connected to each other and to the ground SGND, the second end of the capacitor C62 being connected to the CT+ pin of the processor, the second end of the capacitor C63 being connected to the sampling ground SGND, and the first end of a resistor R97 being connected to the sampling ground SGND, and the second end of the resistor R97 being connected to the second end of the capacitor C65;

[0063] a capacitor C50, a resistor R102, a resistor R105 and a resistor R141, the capacitor C50, the resistor R102 and the resistor R105 being connected in series to form a first series circuit, the first end of the first series circuit being connected to the second end of the resistor R97, the second end of the first series circuit being a voltage output terminal VDD, the first end of the resistor R139 being connected to the second end of the capacitor C65, the second end of the resistor R139 being connected to a node between the resistor R102 and the resistor R105 and to the first end of the resistor R141, and the second end of the resistor R141 being connected to the OVER pin of the processor;

[0064] a comparator U9B, the inverting input terminal of the comparator U9B being connected to the second end of the capacitor C65;

[0065] A second series circuit formed by resistor R136, resistor R138 and resistor R137, the first end of the second series circuit is connected to the inverting input terminal of comparator U9B, the second end of the second series circuit is connected to the ground terminal of capacitor C61, the circuit node between resistor R136 and resistor R138 is connected to the second end of resistor R132, the circuit node between resistor R138 and resistor R137 is connected to the non-inverting input terminal of comparator U9B;

[0066] Capacitor C66, which is connected in parallel with resistor R137;

[0067] Resistor R140, the first end of resistor R140 is connected to the non-inverting input terminal of comparator U9B, and the second end of resistor R140 outputs voltage VDD;

[0068] Capacitor C68 and capacitor C70, the first end of capacitor C68 is connected to the output terminal of comparator U9B and the first end of resistor R141, the second end of capacitor C68 is connected to the ground terminal of capacitor C61, the first end of capacitor C70 is connected to the second end of resistor R141, and the second end of capacitor C70 is connected to the second end of capacitor C68;

[0069] The output short circuit protection circuit comprises:

[0070] Comparator U9A, the positive power supply terminal of comparator U9A is connected to the second end of resistor R105, and the negative power supply terminal of comparator U9A is connected to the second end of capacitor C68;

[0071] Resistor R143, capacitor C72, resistor R145, capacitor C74, resistor R149 and capacitor C77, the second ends of capacitor C72, resistor R145, capacitor C74, resistor R149 and capacitor C77 are connected to each other and grounded to SGND, the first end of resistor R143 is connected to the CT+ pin of the processor, the first end of resistor R145 is connected to the non-inverting input terminal of comparator U9A, the first end of capacitor C74 is connected to the second end of resistor R105, the first end of resistor R149 is connected to the inverting input terminal of comparator U9A, the inverting input terminal of comparator U9A is also connected to the second end of resistor R143, and the first end of capacitor C77 is connected to the output terminal of comparator U9A;

[0072] Resistor R144, the first end of resistor R144 is connected to the second end of resistor R105;

[0073] Resistor R151, the first end of resistor R151 is connected to the second end of resistor R105, and the second end of resistor R151 is connected to the SHORT pin of the processor and the output terminal of comparator U9A.

[0074] Compared with the prior art, the present application has the following advantages:

[0075] 1. The application adopts a two-stage protection structure to protect the transformer, one is to install a protection device in the distribution box, which will melt the fuse after overcurrent, so as to disconnect the passage. Two is to set a protection circuit in the distribution box as the second protection.

[0076] 2. The application improves the design of the fuse assembly, according to different power transformers, the corresponding fuse assembly can be configured, the multiple fuses on the fuse assembly have the functions of overcurrent fusing and supporting, after the multiple fuses are fused, the electric rod can be lifted up through the action of the first compression spring, thereby disconnecting the circuit of the protection device.

[0077] 3. The protection mechanism of the application is convenient to replace, only needs to open the insulating cover, take out the fused fuse assembly, and replace the new fuse assembly.

[0078] 4. The application also has an audible and visual alarm device, the audible and visual alarm device has an independent power supply, and the audible and visual alarm device is controlled by a passive switch, that is, after the electric rod is retracted, the passive switch can be closed to remind the staff. BRIEF DESCRIPTION OF DRAWINGS

[0079] Figure 1 It is a protection device passage state structure diagram of the application.

[0080] Figure 2 It is a protection mechanism schematic diagram of the application.

[0081] Figure 3 It is a structure schematic diagram of the lower pole column of the application.

[0082] Figure 4 It is a structure schematic diagram of the fuse of the application.

[0083] Figure 5 It is a protection device circuit breaking state structure diagram of the application.

[0084] Figure 6 It is a structure schematic diagram of the fused fuse assembly of the application.

[0085] Figure 7 It is a power supply structure schematic diagram of the audible and visual alarm of the application.

[0086] Figure 8 It is a circuit diagram of the audible and visual alarm device of the application.

[0087] Figure 9 It is an output current overload protection circuit diagram of the application.

[0088] Figure 10 It is an output short circuit protection circuit diagram of the application.

[0089] Marked in the drawing: buckle part 1, fuse assembly 2, conductive rod 3, blocking plate 4, protective seat 5, right conductive strip 6, pressure head 7, first compression spring 8, passive switch 9, power supply terminal 10, audible and visual alarm device 11, bottom cavity 12, first terminal 13, buckle mechanism 14, left conductive strip 15, strip-shaped profile 16, clamping plate 17, power supply 18, first elastic electrode 19, insulating cover 20, insulating part 21, upper pole 22, fuse 23, annular blocking ring 24, lower pole 25, second jack 26, first jack 27, column 28, insulating block 71, hard terminal 91, second compression spring 92, insulating support 93, second elastic electrode 94, pressure key 95, contact terminal 96, glass rod slag 211, second end pin 231, glass rod 232, easily expandable liquid 233, resistance wire 234, first end pin 235. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, so that the advantages and characteristics of the present application can be more easily understood by those skilled in the art, and the protection scope of the present application can be more clearly and definitely defined. Obviously, the described embodiments of the present application are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0091] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0092] Embodiment 1: The specific structure of the present application is as follows:

[0093] Please refer to the accompanying drawings Figures 1-7 The protective device of the electrical engineering distribution transformer of the present application comprises a detachable protective seat 5 and a buckle part 1. The protective seat 5 has a conductive strip installation structure in a break state, and the buckle part 1 has a power supply 18 and a protection mechanism. The protective seat 5 is a U-shaped structural member, which has a U-shaped cavity inside. The bottom surface of the U-shaped opening of the protective seat 5 is provided with four through holes, which are a first through hole, a second through hole, a third through hole and a fourth through hole respectively. The conductive strip installation structure in the break state comprises:

[0094] The left conductive strip 15 is fixed at one end to the left cavity of the U-shaped cavity and extends to the front of the first through hole at the other end. The left conductive strip 15 is fixed by a screw, and the extension end is provided with a terminal matching hole.

[0095] The right conductive strip 6 is fixed at one end to the right cavity of the U-shaped cavity and extends to the front of the second through hole at the other end. The right conductive strip 6 is fixed by a screw.

[0096] The housing of the protection seat 5 is provided with two terminal holes, which are opposite to two screws, and the copper terminals are connected to the screws and fastened by the screws.

[0097] After the buckle part 1 buckles the protection seat 5, the circuit of the broken conductive strip installation structure can be connected, and the connected circuit passes through the protection mechanism;

[0098] The protection mechanism comprises:

[0099] The conductive rod telescopic assembly can be telescopically extended into the protection seat 5, and after the conductive rod telescopic assembly is extended into the protection seat 5, the conductive rod telescopic assembly can contact one of the conductive strips, for example, Figure 1 As shown in the figure, the conductive rod telescopic assembly is in contact with the right conductive strip 6 after being extended into the protection seat 5;

[0100] The fuse assembly 2 abuts against and electrically connects the conductive rod telescopic assembly so that the conductive rod telescopic assembly is extended into the protection seat 5, and the fuse assembly has an overcurrent fuse and a length shortening structure;

[0101] The protection seat 5 is provided with an audible and visual alarm device 11.

[0102] The buckle part 1 further has an on-off mechanism capable of connecting the audible and visual alarm device 11, and the on-off mechanism comprises:

[0103] The passive switch 9 is arranged in the buckle part 1, and after the buckle part 1 buckles the protection seat 5, the passive switch 9 is in electrical contact with the audible and visual alarm device 11 and can control the on-off of the audible and visual alarm device 11, and the passive switch 9 is electrically connected to the power supply;

[0104] The pressure head 7 is fixed to the side of the conductive rod telescopic assembly, and after the pressure head 7 is pressed down, the passive switch 9 can be disconnected, and after the pressure head 7 is lifted up, the passive switch 9 is automatically connected, and the lower end of the pressure head 7 is an insulating block 71.

[0105] The buckle part 1 comprises:

[0106] The buckle housing has a battery slot, a straight cavity and a terminal hole, the first end of the straight cavity is opposite to the second through hole, the second end of the straight cavity is connected to the terminal hole, the side of the straight cavity is provided with a side opening, and the power supply 18 is a rechargeable battery which is installed in the battery slot;

[0107] The first elastic electrode 19 is arranged in the side opening, and the round end of the first elastic electrode 19 can be telescopically extended, and the round end is in the straight cavity area;

[0108] The first terminal 13 is protrudedly fixed to the insertion end of the buckle shell, and is electrically connected to the first elastic electrode 19. After the buckle part 1 is inserted into the protection seat 5, the first terminal 13 passes through the first through hole and contacts the left conductive strip 15.

[0109] The conductive rod telescopic assembly comprises the conductive rod 3, and the first compression spring 8. The thick section of the conductive rod 3 is located in the straight cavity, and the thin section of the conductive rod 3 extends to the second through hole. The first compression spring 8 is sleeved on the thin section, one end of the first compression spring 8 abuts against the edge of the second through hole, and the other end of the first compression spring 8 abuts against the step between the thick section and the thin section.

[0110] After the conductive rod 3 is abutted by the fuse assembly, the lower end of the conductive rod 3 contacts the right conductive strip 6.

[0111] The pressure head 7 is an insulating pressure head, and the side of the insulating pressure head is fixed to the conductive rod 3.

[0112] One side of the straight cavity is provided with a blocking plate 4 for limiting the upward distance of the pressure head 7. The blocking plate 4 is used for blocking the pressure head 7 and also blocks the upward movement of the conductive rod 3.

[0113] The fuse assembly comprises:

[0114] The lower pole 25 has a flat end, and the flat end forms an abutting type electrical connection with the conductive rod 3. The other end of the lower pole 25 is provided with an annular stop ring 24. The bottom surface of the annular stop ring 24 is provided with a first insertion hole 27 arranged in an annular array. The center of the flat end of the lower pole 25 is provided with a column 28 perpendicular to the flat end, and the height of the column 28 is less than that of the annular stop ring 24.

[0115] The upper pole 22 is provided with a second insertion hole 26 arranged in an annular array on the first surface opposite to the lower pole 25. After the fuse assembly is positioned, the first elastic electrode 19 contacts the upper pole 22.

[0116] A plurality of fuses 23. The first end pin 235 of the fuse 23 is inserted into the first insertion hole 27, and the second end pin 231 of the fuse 23 is inserted into the second insertion hole 26. When the fuse is blown, the lower pole 25 cannot be lifted when the upper pole 22 is removed. The column 28 is clamped by the clamp, and the lower pole 25 is removed.

[0117] The insulating part 21 is fixed to the second surface of the upper pole 22.

[0118] The end hole is screwed with an insulating cover 20. The insulating cover 20 is arranged to facilitate replacement of the fuse assembly 2.

[0119] The fuse 23 further comprises an electric resistance wire assembly.

[0120] The electric resistance wire assembly comprises:

[0121] a glass rod 232, having two ends connected with the first end pin 235 and the second end pin 231 respectively, and having a cavity inside;

[0122] a resistance wire 234, arranged in the cavity, and having two ends connected with the first end pin 235 and the second end pin 231 respectively;

[0123] an easily-expandable liquid 233, filled in the cavity, when normal current passes through the resistance wire 234, the resistance wire 234 generates low heat, and the heat is not enough to make the easily-expandable liquid 233 expand; when large current passes through the resistance wire 234, the resistance wire 234 generates large heat, and the large heat is absorbed by the easily-expandable liquid 233, so that the easily-expandable liquid 233 expands, and bursts the glass rod 232, and the broken glass rod 232 falls into the annular retaining ring 24, so as to prevent the broken glass rod 232 from entering the straight cavity.

[0124] the sound-light alarm device 11 is fixed on the bottom cavity 12 of the U-shaped cavity, and the shell top is provided with two power supply terminals 10, which are respectively opposite to the third through hole and the fourth through hole;

[0125] the passive switch 9 comprises:

[0126] an insulating support 93, fixed in the buckle part 1, and provided with a contact terminal 96 connected with the positive pole of the power supply 18 and a spring column cavity;

[0127] two electric pins, fixed on the insulating support 93, and capable of entering the third through hole and the fourth through hole respectively, and one-to-one contact with the two power supply terminals, wherein one first electric pin is electrically connected to the negative pole of the power supply 18;

[0128] a second elastic electrode 94, fixed in the insulating support 93, and electrically connected to the second electric pin at the non-stretching end, and opposite to the contact terminal 96 at the stretching end;

[0129] a second compression spring 92, arranged in the spring column cavity;

[0130] a hard terminal 91, having a first end fixed to the upper end of the second compression spring 92, and a second end extending to the upper end of the stretching end and below the contact terminal 96;

[0131] a pressing key 95, fixed with the first end of the hard terminal 91, and having an outer end extending out of the insulating support 93 and opposite to the pressing head 7.

[0132] Embodiment 2:

[0133] The working principle of the protection device of the electrical engineering distribution transformer is as follows:

[0134] like Figures 1-7 As shown, with Figure 1 The assembled protective device is in its initial state. At this time, the conductive rod 3 is in contact with the right conductive strip 6, forming a circuit. The insulating block 71 on the pressure head 7 is pressed down, causing the pressure key 95 to press down. The pressure key 95, along with the hard terminal 91, presses down the extension end of the second compression spring 92 and the second elastic electrode 94, disconnecting the hard terminal 91 from the contact terminal 96. At this time, the audible and visual alarm device 11 is in an open-circuit state.

[0135] Specifically, the current enters from the right conductive bar 6, passes through the conductive rod 3, the lower electrode 25, multiple fuses 23, the upper electrode 22, the first elastic electrode 19, the first terminal 13, and finally exits from the left conductive bar 15.

[0136] When the current entering the right conductive strip 6 exceeds the upper limit of the multiple fuses 23, the fuses 23 generate a large amount of heat. This heat is conducted to the easily expandable fluid 233, causing it to expand and burst the glass rod 232. The glass rod 232 shatters and falls into the bottom surface inside the annular retaining ring 24. At this time, the resistance wire 234 is insufficient to support the lower electrode 25. The conductive rod 3 is then lifted by the first compression spring 8, disconnecting it from the right conductive strip 6 and breaking the circuit.

[0137] After the lower pole post 25 is lifted, the annular retaining ring 24 on it abuts against the lower end of the upper pole post 22.

[0138] As the conductive rod 3 rises, it carries the pressure head 7 upwards simultaneously. After the pressure head 7 rises, the second compression spring 92 lifts the hard terminal 91, which then contacts the contact terminal 96. At the same time, the telescopic end of the second elastic electrode 94 rises and remains in contact with the hard terminal 91, thus creating a circuit for the audible and visual alarm device 11. The horn and LED work synchronously, emitting an alarm sound and flashing light to alert nearby personnel to handle the situation.

[0139] Correspondingly, the protective base 5 is provided with a light-transmitting area for the light from the light-emitting diode to pass through.

[0140] Example 3:

[0141] The bottom end of the protective base 5 is provided with a buckle mechanism 14, which clamps the mounting plate after the buckle is opened by the action of a return spring.

[0142] The outer corners of both ends of the protective seat 5 are provided with sliding grooves, and multiple protective seats 5 are spliced ​​together by sliding into the sliding grooves through strip profiles 16.

[0143] The outer sides of the buckle shell are provided with buckle grooves, and the upper end of the protective seat 5 is provided with a locking plate 17. After the buckle part 1 is inserted into the protective seat 5, the locking plate 17 is engaged in the buckle groove to fix the buckle part 1.

[0144] Embodiment 4:

[0145] The application also includes a circuit which applies the electrical engineering distribution transformer of Embodiments 1 to 3, the circuit comprising an audible and visual alarm circuit and a secondary protection circuit;

[0146] The audible and visual alarm circuit comprises:

[0147] A loudspeaker BZ1, the positive pole of which is connected to the hard terminal 91;

[0148] A triode Q24, the collector of which is connected to the negative pole of the loudspeaker BZ1, and the emitter of which is connected to the ground SGND;

[0149] A resistor R156, the first end of which is connected to the negative pole of the power supply 18, and the second end of which is connected to the base of the triode Q24;

[0150] A resistor R157, the first end of which is connected to the base of the triode Q24, and the second end of which is connected to the emitter of the triode Q24;

[0151] A triode Q25, the emitter of which is connected to the emitter of the triode Q24;

[0152] A resistor R160, the first end of which is connected to the emitter of the triode Q25, and the second end of which is connected to the base of the triode Q25;

[0153] A resistor R159, the first end of which is connected to the base of the triode Q25, and the second end of which is connected to the negative pole of the loudspeaker BZ1;

[0154] A diode D35, which is connected in parallel with the loudspeaker BZ1, wherein the negative pole of the diode D35 is connected to the negative pole of the loudspeaker BZ1;

[0155] A resistor R161, the first end of which is connected to the positive pole of the loudspeaker BZ1;

[0156] A light emitting diode LED1, the negative pole of which is connected to the collector of the triode Q25, and the positive pole of which is connected to the second end of the resistor R161;

[0157] The secondary protection circuit comprises an output current overload protection circuit and an output short circuit protection circuit;

[0158] The output current overload protection circuit comprises:

[0159] A resistor R132 and a capacitor C61, the first end of the resistor R132 is connected to the CT+ pin of the processor, the first end of the capacitor C61 is connected to the second end of the resistor R132, and the second end of the capacitor C61 is connected to the ground SGND;

[0160] a capacitor C64 connected in parallel with the capacitor C61;

[0161] a capacitor C62, a capacitor C65, a capacitor C63, a first end of the capacitor C62, the capacitor C65, the capacitor C63 being connected to a ground SGND, a second end of the capacitor C62 being connected to a CT+ pin of the processor, a second end of the capacitor C63 being connected to a sampling ground SGND, a first end of a resistor R97 being connected to the sampling ground SGND, and a second end of the resistor R97 being connected to a second end of the capacitor C65;

[0162] a capacitor C50, a resistor R102, a resistor R105, a resistor R139, and a resistor R141, the capacitor C50, the resistor R102, and the resistor R105 being connected in series to form a first series circuit, a first end of the first series circuit being connected to a second end of the resistor R97, a second end of the first series circuit being a voltage output terminal VDD, a first end of the resistor R139 being connected to the second end of the capacitor C65, a second end of the resistor R139 being connected to a node between the resistor R102 and the resistor R105 and a first end of the resistor R141, and a second end of the resistor R141 being connected to an OVER pin of the processor;

[0163] a comparator U9B, a non-inverting input terminal of the comparator U9B being connected to the second end of the capacitor C65;

[0164] a second series circuit formed by a resistor R136, a resistor R138, and a resistor R137, a first end of the second series circuit being connected to the non-inverting input terminal of the comparator U9B, and a second end of the second series circuit being connected to a ground pin of the capacitor C61, a node between the resistor R136 and the resistor R138 being connected to a second end of a resistor R132, and a node between the resistor R138 and the resistor R137 being connected to an inverting input terminal of the comparator U9B;

[0165] a capacitor C66 connected in parallel with the resistor R137;

[0166] a resistor R140, a first end of the resistor R140 being connected to the inverting input terminal of the comparator U9B, and a second end of the resistor R140 outputting a voltage VDD;

[0167] a capacitor C68 and a capacitor C70, a first end of the capacitor C68 being connected to an output terminal of the comparator U9B and a first end of the resistor R141, a second end of the capacitor C68 being connected to a ground terminal of the capacitor C61, and a first end of the capacitor C70 being connected to a second end of the resistor R141, and a second end of the capacitor C70 being connected to a second end of the capacitor C68;

[0168] the output short circuit protection circuit comprises:

[0169] A comparator U9A, a second end of the resistor R105 is connected to a positive power supply pin of the comparator U9A, and a second end of the capacitor C68 is connected to a negative power supply pin of the comparator U9A;

[0170] A resistor R143, a capacitor C72, a resistor R145, a capacitor C74, a resistor R149 and a capacitor C77, a second end of the capacitor C72, the resistor R145, the capacitor C74, the resistor R149 and the capacitor C77 are connected to each other and grounded SGND, a first end of the resistor R143 is connected to a CT+ pin of the processor, a first end of the resistor R145 is connected to a non-inverting input terminal of the comparator U9A, a first end of the capacitor C74 is connected to a second end of the resistor R105, a first end of the resistor R149 is connected to an inverting input terminal of the comparator U9A, the inverting input terminal of the comparator U9A is also connected to a second end of the resistor R143, and a first end of the capacitor C77 is connected to an output terminal of the comparator U9A;

[0171] A resistor R144, a first end of the resistor R144 is connected to a second end of the resistor R105;

[0172] A resistor R151, a first end of the resistor R151 is connected to a second end of the resistor R105, and a second end of the resistor R151 is connected to a SHORT pin of the processor and an output terminal of the comparator U9A.

[0173] The circuit of the present application is a secondary protection circuit, that is, when the protection device of the embodiments 1-3 fails, the secondary protection circuit can respond in time to avoid damage to the transformer.

[0174] In summary, the present application adopts a two-level protection structure to protect the transformer, that is, a protection device is installed in the distribution box, which will melt the fuse when overcurrent occurs to disconnect the circuit. Two protection circuits are provided in the distribution box as secondary protection. The present application improves the design of the fuse assembly, and according to different power transformers, corresponding fuse assemblies can be configured. The multiple fuses on the fuse assembly have the functions of overcurrent fusing and supporting. After the multiple fuses are fused, the first compression spring can lift the conducting rod to disconnect the circuit of the protection device. The protection mechanism of the present application is easy to replace, only needs to open the insulating cover, take out the fused fuse assembly, and replace the new fuse assembly. The present application also provides an audible and visual alarm device, which has an independent power supply. The audible and visual alarm device is controlled by a passive switch, that is, after the conducting rod is retracted, the passive switch can be closed to remind the staff.

[0175] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, based on the content of the present application specification and drawings, are also included in the patent protection scope of the present application.

Claims

1. A protective device for a power distribution transformer in electrical engineering, comprising a detachably connected protective base (5) and a fastener (1), wherein the protective base (5) has a conductive strip mounting structure in an open-circuit state, characterized in that, The buckle (1) has a power supply (18) and a protection mechanism; After the buckle (1) is fastened to the protective seat (5), it can connect the circuit of the disconnected conductive strip mounting structure, and the connected circuit passes through the protection mechanism. The protection mechanism includes: A telescopic conductive rod assembly that is retractable and can extend into the protective seat (5), and the telescopic conductive rod assembly can contact one of the conductive strips therein after extending into the protective seat (5); A fuse assembly is abutted against and electrically connected to the conductive rod telescopic assembly so that the conductive rod telescopic assembly extends into the protective seat (5). The fuse assembly has an overcurrent fuse structure that reduces the length. The protective base (5) is equipped with an audible and visual alarm device (11). The buckle (1) also has an on / off mechanism capable of activating the audible and visual alarm device (11), the on / off mechanism comprising: A passive switch (9) is provided on the buckle (1). After the buckle (1) is inserted into the protective seat (5), the passive switch (9) is electrically connected to the sound and light alarm device (11) and can control the on and off of the sound and light alarm device (11). The passive switch (9) is electrically connected to the power supply. The pressure head (7) is fixed to the conductive rod telescopic assembly. When the pressure head (7) is pressed down, it can disconnect the passive switch (9), and when the pressure head (7) is raised, the passive switch (9) will automatically turn on. The protective seat (5) is a U-shaped structural component with a U-shaped cavity inside. The bottom surface of the U-shaped opening of the protective seat (5) is provided with four through holes, namely the first through hole, the second through hole, the third through hole and the fourth through hole. The buckle (1) includes: The casing has a battery slot, a straight cavity and an end hole. The first end of the straight cavity is directly opposite the second through hole, and its second end is connected to the end hole. A side opening is provided on the side of the straight cavity. A first elastic electrode (19) is provided in the side opening; The fuse assembly includes: The lower electrode post (25) has a flat end at one end, which forms an abutting electrical connection with the conductive rod (3). The other end of the lower electrode post (25) is provided with an annular retaining ring (24), and the bottom surface of the annular retaining ring (24) is provided with a first insertion hole (27) arranged in a ring array. The upper electrode post (22) has a second socket (26) arranged in a ring array on the first surface facing the lower electrode post (25). After the fuse assembly is positioned, the first elastic electrode (19) and the upper electrode post (22) come into contact. A plurality of fuses (23), wherein the first pin (235) of the fuse (23) is inserted into the first socket (27), and the second pin (231) is inserted into the second socket (26); An insulating element (21) is fixed to the second side of the upper pole post (22); The fuse (23) also includes a resistance wire assembly; The resistance wire assembly includes: A glass rod (232) has its two ends connected to the first end pin (235) and the second end pin (231) respectively, and has a cavity inside. A resistance wire (234) is disposed in the cavity, and its two ends are respectively connected to the first end pin (235) and the second end pin (231). The expandable liquid (233) is filled into the cavity.

2. The protective device for an electrical engineering distribution transformer according to claim 1, characterized in that, The conductive strip mounting structure in an open-circuit state includes: The left conductive strip (15) has one end fixed to the left cavity of the U-shaped cavity and the other end extending directly below the first through hole; The right conductive strip (6) has one end fixed to the right cavity of the U-shaped cavity and the other end extending directly below the second through hole.

3. The protective device for an electrical engineering distribution transformer according to claim 2, characterized in that, The power source (18) is a rechargeable battery, which is installed in the battery compartment; The circular end of the first elastic electrode (19) is retractable and is located in the straight cavity region; The buckle (1) also includes a first terminal (13), which is protruding and fixed to the insertion end of the buckle shell and is electrically connected to the first elastic electrode (19). After the buckle (1) is inserted into the protective seat (5), the first terminal (13) passes through the first through hole and contacts the left conductive strip (15).

4. A protective device for an electrical engineering distribution transformer according to claim 3, characterized in that, The conductive rod telescopic assembly includes a conductive rod (3) and a first compression spring (8). The thick section of the conductive rod (3) is located in the straight cavity, and its thin section extends to the second through hole. The first compression spring (8) is sleeved on the thin section, with one end abutting against the edge of the inner opening of the second through hole and the other end abutting against the step between the thick section and the thin section. After the conductive rod (3) is pressed against the fuse assembly, its lower end contacts the right conductive strip (6). The pressure head (7) is an insulating pressure head, which is fixed to the conductive rod (3).

5. A protective device for an electrical engineering distribution transformer according to claim 4, characterized in that, A baffle plate (4) is provided on one side of the straight cavity to limit the upward distance of the pressure head (7).

6. A protective device for an electrical engineering distribution transformer according to claim 2, characterized in that, The sound and light alarm device (11) is fixed in the bottom cavity of the U-shaped cavity, and its shell top is provided with two power supply terminals, which are respectively facing the third through hole and the fourth through hole; The passive switch (9) includes: An insulating bracket (93) is fixed inside the buckle (1), and is provided with a contact terminal (96) connected to the positive terminal of the power supply (18) and a spring cylinder cavity; Two electrical pins are fixed to the insulating bracket (93). The two electrical pins can enter the third through hole and the fourth through hole respectively, and make one-to-one contact with the two power supply terminals. One of the first electrical pins is electrically connected to the negative terminal of the power supply (18). The second elastic electrode (94) is fixed inside the insulating bracket (93), with its non-telescopic end electrically connected to the second electrical pin and its telescopic end facing the contact terminal (96). A second compression spring (92) is provided in the spring column cavity; A rigid terminal (91) has its first end fixed to the upper end of the second compression spring (92) and its second end extending to the upper end of the telescopic end and located below the contact terminal (96). The key (95) is fixed to the first end of the hard terminal (91), and its outer end extends out of the insulating bracket (93) and faces the pressure head (7).

7. A protective device for an electrical engineering distribution transformer according to claim 1, characterized in that, An insulating cap (20) is screwed onto the end hole.

8. A circuit, characterized in that, This circuit is applied to a protective device for an electrical engineering distribution transformer as described in any one of claims 1-7. The circuit includes an audible and visual alarm circuit and a secondary protection circuit. The audible and visual alarm circuit includes: Speaker BZ1, positive terminal connected to hard terminal (91); Transistor Q24, whose collector is connected to the negative terminal of speaker BZ1, and whose emitter is grounded to SGND; Resistor R156, the first end of which is connected to the negative terminal of power supply (18), and the second end of which is connected to the base of transistor Q24; Resistor R157, the first end of which is connected to the base of transistor Q24, and the second end of which is connected to the emitter of transistor Q24; Transistor Q25, the emitter of which is connected to the emitter of transistor Q24; Resistor R160, the first end of which is connected to the emitter of transistor Q25, and the second end of which is connected to the base of transistor Q25; Resistor R159, the first end of which is connected to the base of transistor Q25, and the second end of which is connected to the negative terminal of speaker BZ1; Diode D35 is connected in parallel with speaker BZ1, wherein the cathode of diode D35 is connected to the cathode of speaker BZ1; Resistor R161, the first terminal of which is connected to the positive terminal of speaker BZ1; The negative terminal of LED1 is connected to the collector of transistor Q25, and the positive terminal is connected to the second terminal of resistor R161; The secondary protection circuit includes an output current overload protection circuit and an output short circuit protection circuit. The output current overload protection circuit includes: Resistor R132 and capacitor C61, the first end of resistor R132 is connected to the CT+ pin of the processor, the second end of resistor R132 is connected to the first end of capacitor C61, and the second end of capacitor C61 is grounded to SGND. Capacitor C64 is connected in parallel with capacitor C61; Capacitors C62, C65, and C63, and resistor R97 are provided. The first terminals of capacitors C62, C65, and C63 are interconnected and grounded to SGND. The second terminal of capacitor C62 is connected to the CT+ pin of the processor. The second terminal of capacitor C63 is connected to the sampling ground SGND. The first terminal of resistor R97 is connected to the sampling ground SGND, and its second terminal is connected to the second terminal of capacitor C65. Capacitor C50, resistors R102, R105, R139, and R141 are connected in sequence to form a first series circuit. The first terminal of the first series circuit is connected to the second terminal of resistor R97. The second terminal of the first series circuit is the voltage output terminal VDD. The first terminal of resistor R139 is connected to the second terminal of capacitor C65. Its second terminal is connected to the node between resistors R102 and R105 and the first terminal of resistor R141. The second terminal of resistor R141 is connected to the OVER pin of the processor. Comparator U9B, the inverting input of which is connected to the second terminal of capacitor C65; A second series circuit is formed by resistors R136, R138, and R137 connected in series. The first terminal of the second series circuit is connected to the inverting input terminal of comparator U9B, and the second terminal is connected to the grounding pin of capacitor C61. The circuit node between resistors R136 and R138 is connected to the second terminal of resistor R132, and the circuit node between resistors R138 and R137 is connected to the non-inverting input terminal of comparator U9B. Capacitor C66 is connected in parallel with resistor R137; Resistor R140, the first terminal of which is connected to the non-inverting input terminal of comparator U9B, and the second terminal of which outputs voltage VDD; Capacitors C68 and C70 are provided. The first terminal of capacitor C68 is connected to the output terminal of comparator U9B and the first terminal of resistor R141. The second terminal of capacitor C68 is connected to the ground terminal of capacitor C61. The first terminal of capacitor C70 is connected to the second terminal of resistor R141, and its second terminal is connected to the second terminal of capacitor C68. The output short-circuit protection circuit includes: Comparator U9A, the positive power supply pin of which is connected to the second terminal of resistor R105, and the negative power supply pin of which is connected to the second terminal of capacitor C68; Resistor R143, capacitor C72, resistor R145, capacitor C74, resistor R149, and capacitor C77. The second terminals of capacitor C72, resistor R145, capacitor C74, resistor R149, and capacitor C77 are interconnected and grounded to SGND. The first terminal of resistor R143 is connected to the CT+ pin of the processor, and its second terminal is connected to the first terminal of capacitor C72. The first terminal of resistor R145 is connected to the non-inverting input terminal of comparator U9A. The first terminal of capacitor C74 is connected to the second terminal of resistor R105. The first terminal of resistor R149 is connected to the inverting input terminal of comparator U9A. The inverting input terminal of comparator U9A is also connected to the second terminal of resistor R143. The first terminal of capacitor C77 is connected to the output terminal of comparator U9A. Resistor R144, the first terminal of which is connected to the second terminal of resistor R105; Resistor R151, the first end of which is connected to the second end of resistor R105, and the second end of which is connected to the processor's SHORT pin and the output of comparator U9A.

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