CN104201068A - Direct current circuit breaker - Google Patents

Abstract

The invention discloses a direct current circuit breaker. The invention provides an anti-shock and vibration fast repulsion tripping mechanism and a method for integrating the repulsion compensation structure. The DC circuit breaker of the present invention can effectively withstand mechanical shocks such as bumps and vibrations, has a very small chance of false tripping, and has high reliability during normal operation. At the same time, the present invention uses the repulsive disk as the reaction device of the tripping mechanism, and utilizes the energy of the repulsive disk to open the gate, thereby significantly improving the action speed of the DC circuit breaker and greatly shortening the inherent opening time of the circuit breaker. In addition, the DC circuit breaker of the present invention utilizes the structure of the moving contact guide rod to convert the elastic force of the drive spring used for opening the switch into the holding force between the moving and static contacts when the switch is closed, so as to ensure that the large short-circuit current Under this condition, the moving contact is not repelled, which improves the short-term withstand capacity of the DC circuit breaker.

Description

A DC circuit breaker

technical field

The invention belongs to the field of DC circuit breakers, in particular to a DC circuit breaker which utilizes the principle of a repulsive force disc and a quick tripping mechanism to prevent shock and vibration, and uses repulsive force compensation to improve short-term tolerance.

Background technique

Due to the unique advantages of the DC power supply system, people pay more and more attention to the research of the DC power supply system, and the connection between the DC power supply system and daily life is getting closer and closer. At present, many important industries such as urban trolleybus, subway, smelting, chemical industry, solar power generation, rolling material, ship power, mining and so on have adopted DC power supply system.

The DC circuit breaker is the guarantee for the safe operation of the DC power supply system. It has the protection function of cutting off the fault current of the circuit and is the most important protection component in the DC system. As people's requirements for the reliability of the power supply system become more and more stringent, and the DC power load capacity continues to increase, the requirements for the performance of DC circuit breakers continue to increase. The operating mechanism and tripping system are one of the core components of the work of the circuit breaker. The reliability of the circuit breaker must be based on the reliable operation of the mechanism and the tripping device, especially in applications such as ships and locomotives. It has strong anti-shock, vibration and anti-tilt capabilities, and cannot be accidentally tripped under the influence of the external environment. And out of the requirements of protection coordination, for the circuit breaker on the outlet side of the generator, it is required that the circuit breaker can withstand the short-circuit current for a certain period of time without being repelled by the electrodynamic repulsion. At the same time, due to the huge breaking energy of the DC short-circuit current, the design of the mechanism and the tripping device must also be quickly required to extinguish the arc in time to cut off the fault current, thereby reducing the ablation of the contacts and the damage to the arc extinguishing chamber, and also It can reduce the harm of the thermodynamic effect of the fault current to the whole system. However, there is a contradiction between the rapidity and reliability of the mechanism, and in order to meet the requirements of thermal stability, the mass of the moving part of the mechanism is relatively large, which will also make it difficult to realize the rapid movement of the mechanism.

Contents of the invention

The object of the present invention is: aiming at the design difficulties of the above-mentioned DC circuit breaker, the present invention provides an opening operating mechanism that is rapidly driven by tripping energy, and proposes a method for preventing shock vibration and electric repulsion compensation of the mechanism, and realizes Integrated design of tripping and opening. It solves the problem that the spring operating mechanism of the DC circuit breaker cannot meet the design requirements of fast and reliable breaking, and also solves the technical problem that the energy of the repulsion plate cannot be effectively utilized during the use of the high-speed electromagnetic repulsion device. Provided is a method that can effectively utilize the motion energy of the repulsion disc, meet the requirements of fast tripping and high-speed contact opening, improve the breaking performance of the circuit breaker, and reduce the ablation of the arc on the contact system of the circuit breaker.

The invention discloses the following DC circuit breaker, which is characterized in that:

The DC circuit breaker includes an upper busbar, a lower busbar, a static contact, a moving contact, a moving contact guide rod, a limit shaft, an upper connecting shaft, a lower connecting shaft, an upper connecting rod, a lower connecting rod, an upper driving Spring, lower drive spring, connecting rod sleeve, shift fork, lock push rod, lock holding torsion spring, repulsion push rod, metal repulsion disk, repulsion disk coil, magnetizing block, conductive block, soft connection, tripping handle arm, trip transition block, insulating frame, of which:

The upper and lower busbars are fixedly connected to the rack as current input and output terminals;

The static contact is fixedly installed on the upper busbar, and the moving contact fixedly installed on the moving contact guide rod is used as an electrical contact contact pair; the different height positions of the moving contact guide rod pass through the upper and lower connecting shafts respectively , and the upper and lower connecting rods are respectively rotated and fixed on the upper and lower connecting shafts, the other end of the upper connecting rod is installed in the connecting rod sleeve fixed on the frame, and the inner diameter of the connecting rod sleeve is slightly larger than the upper connecting rod Radius, the upper connecting rod can move along the direction restricted by the connecting rod sleeve, the lower connecting rod is installed on the frame, and the frame is designed with a guide hole at the connection position with the lower connecting rod to make the lower connecting rod The rod moves along the horizontal direction, and then the movable contact guide rod can rotate freely around the upper and lower connecting shafts;

The upper and lower connecting rods, the connecting rod sleeve and the frame are equipped with pre-compressed upper and lower driving springs, and the moving contact guide rod is connected with the conductive block with a soft connection. The current flow direction between the head and guide rods is opposite, which will generate electric repulsion on the moving contacts. At the same time, because the elastic force of the lower driving spring passes through the upper connecting shaft, the moving contact guide rod is used as a lever to convert a certain pressure of the moving and static contacts. And the pressure is converted into a holding force on the contacts, which is used to compensate the electrodynamic repulsion of the DC circuit breaker;

The repulsion disk coil, the metal repulsion disk, the repulsion push rod, the trip lever, the trip conversion block, the upper drive spring, and the lower drive spring together constitute the tripping mechanism of the DC circuit breaker;

The lock push rod is installed on the moving contact guide rod, the lock push rod can rotate around its fixed axis, the lock push rod is provided with the holding force for the lock catch push rod by one end of the lock retaining torsion spring, and the lock The other end of the buckle holding torsion spring is fixed on the guide rod of the moving contact. The locking rod is used to prevent the fork from rotating and unlocking due to accidental impact and vibration. The chance of false tripping of the tripping mechanism is extremely small;

The repulsion push rod is fixedly connected with the metal repulsion disk. The repulsion push rod includes a small front end and a boss. When the repulsion push rod moves, it can drive the trip arm and the trip conversion block to rotate synchronously. The repulsion push rod of this structure is In the process of moving towards the moving contact guide rod, the small front end first collides with the lock ejector rod to unlock the tripping mechanism, and then drives the moving contact guide rod to move, and completes the rapid movement under the joint action of the repulsive push rod and the upper and lower driving springs. The gate is opened; the magnetizing block is made of ferromagnetic material and fixed on the moving contact guide rod in a concave shape. The conductive circuit formed by the conductive block, the soft connection and the moving contact guide rod is in a U-shaped conductive form. The current flow direction of the contact guide rod is opposite, and the two opposite currents can generate an electric repulsion force. When the circuit breaker flows a short-circuit current, the repulsion force becomes the contact pressure through the upper connecting shaft to provide compensation for the electric repulsion force. The moving contact guide rod When current flows, a magnetic field will be generated around. Due to the existence of ferromagnetic materials, most of the magnetic induction lines will pass through the concave magnetization block, which is used to enhance the electrodynamic repulsion compensation effect on the DC circuit breaker;

The limit shaft passes through the special-shaped hole on the movable contact guide rod, the limit shaft is fixed to the frame, limits the range of motion of the movable contact guide rod, and plays the role of a rotating shaft after touching the special-shaped hole;

The shift fork is connected to the closing mechanism of the circuit breaker, and can move horizontally in the closing position and the opening position, and rotate clockwise from the horizontal position around the left connecting shaft to a certain extent. The upper part of the shift fork is a raised structure. The height of the raised structure is consistent with that of the upper connecting shaft, and the protrusion pushes the connecting shaft to complete the closing process when closing;

The coil of the repulsion disk is placed facing the metal repulsion disk, fixed on the frame, and externally connected with a capacitor discharge circuit controlled by a thyristor, and the movement of the metal repulsion disk is driven by an external circuit control;

The frame is fixed on the installation ground of the circuit breaker, and the limit buckle is installed on the frame to ensure that the moving contact guide rod, the metal repulsion plate, the trip arm and the trip conversion block will not move beyond the design range.

Effect of the present invention is reflected in:

1. The DC circuit breaker of the present invention can effectively withstand mechanical shocks such as bumps and vibrations by using the structure of the locking ejector rod. When the locking ejector rod is closed, it can ensure that the circuit breaker will not accidentally trip due to external vibrations, and the probability of malfunction is extremely small. .

2. The present invention is designed with two repulsion compensation methods: (1) U-shaped conductive circuit, which uses the electromagnetic force generated by the conductive circuit to compensate the electric repulsion of the contact; (2) utilizes the leverage of the moving contact guide rod in the closed state , use the elastic force of the driving spring to compensate the electric repulsion force, these two repulsion force compensation structures can greatly improve the reliability of the closing operation, and improve the rated co-current capacity of the circuit breaker.

3. The DC circuit breaker also uses the repulsion disk as the tripping response device and the moving contact drive device. The repulsion disk coil is driven by a special discharge circuit controlled by an external thyristor, so the movement process of the repulsion disk is not changed by the short-circuit current, and the time error of each operation is very small, which is easy to control. Due to the characteristics of fast starting, high speed, and large thrust of the repulsion plate, the tripping speed of the device is fast, which effectively improves the action speed of the DC circuit breaker, and thus greatly shortens the inherent opening time of the circuit breaker.

Description of drawings

Fig. 1 is a structure diagram of the closing connection relationship of a DC circuit breaker;

Fig. 2 is a model diagram of an electromagnetic repulsion mechanism;

Fig. 3 is a schematic diagram of a repulsion push rod;

Fig. 4 is a structural diagram of the opening connection relationship of a DC circuit breaker;

Among them: 1 is the upper busbar; 2 is the lower busbar; 3 is the static contact; 4 is the moving contact; 5 is the moving contact guide rod; 6 is the limit shaft; 7 is the upper connecting shaft; 8 is the lower connection Shaft; 9 is the upper connecting rod; 10 is the lower connecting rod; 11 is the upper drive spring; 12 is the lower drive spring; 13 is the connecting rod sleeve; 14 is the shift fork; 15 is the lock push rod; 16 is the repulsion push rod 17 is a metal repulsion disk; 18 is a repulsion disk coil; 19 is a magnetic block; 20 is a conductive block; 21 is a soft connection;

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings.

Referring to accompanying drawing 1, the preferred example of the present invention is a DC circuit breaker with anti-shock and vibration quick repulsion tripping mechanism and repulsion compensation, including key modules such as bracket, conductive circuit, electric repulsion compensation, anti-shock vibration, quick tripping, etc. . The frame 24 plays the role of fixing each module and other components. The conductive circuit is composed of upper busbar 1, static contact 3, moving contact 4, moving contact guide rod 5, soft connection 21, conductive block 20, and lower busbar 2. The upper busbar 1 is a flat copper bar placed horizontally, fixed on the frame 24, and a static contact 3 is protrudingly installed at the lower part of a section, and a static contact of silver-based material is installed on the static contact 3.

When the circuit breaker is in the closed and locked state, the conductive circuit is connected. At this time, the circuit breaker is in a normal working state. The normal working state is: the limit shaft 6 is in the middle position of the moving contact guide rod 5, and the shift fork 14 is in the closing position. Withstand the upper connecting shaft 7, and now the lower driving spring 12 is in a compressed state, which generates a torque on the connecting shaft 7 above the movable contact guide rod 5, and this torque provides contact pressure for closing. The lower busbar 2 protrudes from the conductive block 20 as the base of the soft connection 21 and is connected with the moving contact guide rod 5 to ensure that the moving contact guide rod 5 has a good flow capacity during movement. Because the shift fork 14 is restricted by the lock push rod 15, it cannot rotate clockwise. At this time, the circuit breaker lock can prevent the accidental tripping of the circuit breaker even when it receives mechanical shocks such as severe shock and vibration from the outside, which is excellent. To ensure the reliability of the latch in this state.

Since the conductive block 20, the flexible connection 21, and the movable contact guide rod 5 of the conductive part are in a U-shaped conductive form, the current flow directions of the conductive block 20 and the movable contact guide rod 5 are opposite. When a short-circuit fault occurs in the system where the circuit breaker is located, a short-circuit current will flow through the conductive circuit of the circuit breaker, and the short-circuit current is in the lower busbar. These two currents flowing in opposite directions can generate electrodynamic repulsion, because the existence of the magnetization block 19 will make the magnetic field stronger. Concentrate and strengthen the electric repulsion. This electric repulsion is added between the dynamic and static electric shocks through the upper connecting shaft 7, which improves the contact pressure. The contact pressure generated by the resultant force of current repulsion and the force of the aforementioned driving spring can offset the electric repulsion between the dynamic and static electric shocks caused by the short-circuit current, and the dynamic and static contacts are tightly closed at this time.

The DC circuit breaker will perform opening operation in the event of a short-circuit fault, see attached drawings 2 and 3. The operation process of the opening process is: when a short-circuit fault occurs in the system, the controller detects the short-circuit current signal and generates a trigger signal for the thyristor, thereby triggering the conduction of the thyristor VT. After the thyristor VT is turned on, the capacitor C that has stored energy will quickly discharge to the repulsion disk coil 18 to generate a pulse current; based on the principle of electromagnetic induction eddy current, the metal repulsion disk 17 will generate electromagnetic repulsion F to push the repulsion push rod 16 fast movement. The repulsion push rod 16 includes a small front end and a boss. In the process of moving to the left, the repulsion push rod 16 first contacts the lock push rod 15 by the small front end, and pushes the lock push rod 15 to rotate counterclockwise. After the rod 15 rotates at a certain angle, it loses the lock to the shift fork 14. At this time, the shift fork 14 is only subjected to the horizontal force and does not rotate, so the circuit breaker will not trip, and the circuit breaker is in an unlocked state. The repulsion push rod 14 continues to move until the boss at the upper end contacts the tripping lever 22, and the tripping lever 22 rotates clockwise to drive the tripping conversion block 23 to rotate. During the rotation of the tripping conversion block 23, the left end presses the shift fork 14 to dial The fork 14 rotates, the upper connecting shaft 7 breaks away, and the circuit breaker is in a tripped state. The moving contact guide rod 5 of the circuit breaker in the tripped state moves to the left under the elastic force of the upper and lower driving springs 11 and 12, and the moving direction is limited by the limit shaft 6 and the connecting rod sleeve 13, and the circuit breaker starts Open the gate, and now the repulsion push rod 16 continues to move, and the thicker part of the front end collides with the moving contact guide rod 5 to accelerate the movement of the moving contact guide rod 5 until reaching the maximum opening distance. Since the moving speed of the metal repulsion disk 17 is very high, this process can significantly reduce the inherent opening time of the DC circuit breaker.

Referring to Figure 4, after the DC circuit breaker completes a quick opening operation, under the action of each return spring, each component is reset, and the shift fork 14 is driven by an external mechanism to move to the opening position, so as to perform closing action and next opening operate. The closing process is specifically as follows: the shift fork 14 is driven by an external mechanism to move to the right, pushing the upper connecting shaft 7 to move, at this time, the moving contact guide rod 5 rotates with the limit shaft 6 as the rotating shaft, and the lock is locked after the moving and static contacts are in contact. The push rod 15 is returned to its original position by the action of the torsion spring.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments. It cannot be determined that the specific embodiments of the present invention are limited thereto. Under the circumstances, some simple deduction or replacement can also be made, which should be regarded as belonging to the scope of patent protection determined by the submitted claims of the present invention.

Claims (1)

1. a DC circuit breaker, is characterized in that:

Described DC circuit breaker comprises that busbar, lower busbar, fixed contact, moving contact, moving contact guide rod, limit shaft, upper connecting axle, lower connecting axle, upper connecting rod, lower connecting rod, upper driving spring, lower driving spring, connecting rod sleeve, shift fork, snap close push rod, snap close keep torsion spring, repulsion push rod, metal repulsion dish, repulsion dish coil, increase magnetic patch, conducting block, are flexible coupling, dropout connecting lever, dropout conversion block, insulation frame, wherein:

Described upper and lower busbar is fixedly connected with described frame, as electric current in-out end;

Described fixed contact is fixedly installed in busbar, with the moving contact that is fixedly installed in moving contact guide rod as electrically contacting contact pair, described moving contact guide rod differing heights position is respectively through upper, lower connecting axle, and by upper, lower connecting rod is rotationally connected and is fixed on respectively, on lower connecting axle, the upper connecting rod other end is installed in the connecting rod sleeve that is fixed on described frame, connecting rod sleeve diameter is a bit larger tham upper connecting rod radius, the direction that upper connecting rod can limit along connecting rod sleeve is moved, lower connecting rod is arranged in described frame, described frame is being designed with pilot hole with lower connecting rod link position place, so that lower connecting rod is along horizontal motion, and and then make the moving contact guide rod can be around upper, lower connecting axle freely rotates,

Precompressed upper and lower driving spring is housed between described upper and lower connecting rod and connecting rod sleeve, described frame, moving contact guide rod is connected with being flexible coupling with conducting block, because electric current current direction between conducting block and moving contact guide rod is contrary, can on moving contact, produce electrodynamic repulsion force, elastic force due to lower driving spring passes through upper connecting axle simultaneously, take the pressure of moving contact guide rod certain dynamic/static contact as lever is converted to, this repulsion and pressure are converted to the confining force to contact, the described electrodynamic repulsion force that the confining force of contact is used for to compensating direct current circuit breaker;

Preferably, described repulsion dish coil, metal repulsion dish, repulsion push rod, dropout connecting lever, dropout conversion block, upper driving spring, lower driving spring form the tripping mechanism of DC circuit breaker jointly;

Described snap close push rod is installed on moving contact guide rod, snap close push rod can be around its fixed axis rotation, snap close push rod keeps one end of torsion spring to be provided for the confining force of snap close push rod by snap close, snap close keeps the torsion spring other end to be fixed on moving contact guide rod, snap close push rod is used for preventing that tripping mechanism false tripping probability is minimum because accidental shock vibration causes shift fork rotation release;

Described repulsion push rod is fixedly connected with metal repulsion dish, repulsion push rod comprises a tiny front end and boss, during repulsion pushrod movement, can drive dropout connecting lever and the motion of dropout conversion block synchronous rotary, the repulsion push rod of this structure is in moving contact guide rod motion process, first by tiny front end and snap close push rod, collided, release tripping mechanism, then drive the motion of moving contact guide rod, under repulsion push rod and upper and lower driving spring acting in conjunction, complete quick acting switching-off, described increasing magnetic patch is fixed on moving contact guide rod by ferromagnetic material concavity, conducting block, be flexible coupling, form is conducted electricity in U-shaped in the galvanic circle that moving contact guide rod forms, conducting block is contrary with moving contact guide rod direction of current flow, the electric current of these two opposite courses can produce electrodynamic repulsion force, when circuit breaker short circuit current flow this repulsion by connecting axle to become contact pressure be that electrodynamic repulsion force affords redress, during moving contact guide rod current flowing, can produce around magnetic field, existence due to ferromagnetic material, most of line of magnetic induction can increase magnetic patch and pass from spill, for strengthening the electrodynamic repulsion force compensation effect to DC circuit breaker,

Described limit shaft is through the profiled holes on moving contact guide rod, and limit shaft and frame are fixed, and limits the range of movement of moving contact guide rod, and after contact profiled holes, plays the effect of rotating shaft;

Described shift fork is connected with breaker switching-on mechanism, can horizontal direction in closing position and open position translation, and around left connecting axle certain amplitude from horizontal level clockwise rotation, shift fork top is bulge-structure, bulge-structure is consistent with upper connecting axle height, and during combined floodgate, projection promotes connecting axle and completes making process;

Described repulsion dish coil and metal repulsion dish be over against placement, in fixing and frame, and the capacitor discharging circuit of external thyristor control, by external circuit, control and drive metal repulsion dish to move;

Described frame is fixed on circuit breaker installation ground, and limit fastener is installed in frame, and limit fastener guarantees that moving contact guide rod, metal repulsion dish, dropout connecting lever, the unlikely motion of dropout conversion block exceed scope of design.