CN221861569U - An electric fusion protection device - Google Patents

Abstract

The utility model provides an electric fusion protection electric appliance, which at least comprises a circuit breaker and a fuse, wherein the circuit breaker at least comprises an insulating shell, a repulsive force type fixed contact, a moving contact, an arc extinguishing chamber, an operating mechanism, a first wiring end and a second wiring end, wherein at least one normally open type switch device is arranged at the two ends of the fuse, the normally open type switch device and the fuse form a normally open type fuse device, and the two ends of the normally open type fuse device are connected between two repulsive force type fixed contacts or between one repulsive force type fixed contact and the moving contact or between two repulsive force type fixed contacts and the moving contact or between the first wiring end and the second wiring end or between the first wiring end and the moving contact or between the second wiring end and the moving contact; the normally open type switch device is directly or indirectly driven to be closed by a passive contact or/and an electromagnetic device. The problems of temperature rise, misoperation and the like caused by metallurgical effect of a large-current and high-voltage system and the serial and parallel connection of fuses in an electric loop are solved, and the stability of the system is improved.

Description

An electric fusion protection device

Technical Field

The utility model belongs to the technical field of low-voltage electrical appliances, and in particular relates to an electrical fusion protection appliance.

Background Art

Driven by the dual-carbon strategy, with the explosive growth of new energy such as wind power, photovoltaics and energy storage and their development towards larger capacity, in order to obtain greater power and lower costs, it is necessary to increase the high voltage of the DC system to a higher level, and increase the DC side voltage to above DC2000V or even higher voltage; as the power increases, the capacity of the transformer or battery required by the system is also increasing. When there is a short circuit between poles or phases, the short-circuit current generated is also increasing, reaching more than 50kA.

The system of high voltage and large short-circuit current requires a protective device with fast breaking speed, low cost, high safety and good reliability. Circuit breakers are key protection devices for low-voltage DC. Therefore, the DC fault breaking and protection technology of circuit breakers is a decisive factor in ensuring the safe operation of new energy systems.

Most of the existing solutions use a combination of disconnector + fuse in series. This solution has some shortcomings in practical applications. On the one hand, the fuse is always energized when the power supply system is in operation. The high temperature rise generated when the fuse is working will have an adverse effect on the safe operation of the system and will also consume part of the circuit power consumption. On the other hand, in order to solve the problem of excessive temperature rise, most of the fuses currently used in energy storage or photovoltaic systems are configured with a current greater than 170% of the rated current, which will lead to a dead zone in the system. In addition, larger fuses need to be selected, which will cause the switch protection equipment to be larger in size and the fuse cost to be higher. It can no longer meet the main needs of new energy for safety, reliability and low cost. The existing circuit breaker structure, such as the arc extinguishing system with air dielectric insulation in the arc extinguishing grid area, is also difficult to interrupt such high voltage and short-circuit current. It can only make the volume larger, but loses its economic efficiency. In addition, mechanical circuit breakers have insufficient breaking capacity and long breaking time, which are no longer suitable for the development and demand of new energy. Solid-state circuit breakers have the characteristics of small size, long service life, and fast action speed. They can cut off the fault line before the fault current rises to harm the power equipment. However, solid-state circuit breakers have problems such as large loss and high cost, which are not suitable for large-scale application. A few DC fast circuit breakers abroad can achieve fault isolation within milliseconds, but they are expensive and have technical barriers.

Fuses are disposable products, while circuit breakers are reusable products. Fuses have better ampere-second performance in breaking high voltage and large short-circuit fault currents, while circuit breakers can break low overload fault currents multiple times and perform normal opening and closing. The advantages and disadvantages of both are obvious. How to combine the advantages of fuses and circuit breakers to create a new mechanism electrical appliance is a major technical problem that needs to be solved in the low-voltage electrical appliance industry.

Utility Model Content

Based on the above background, the utility model provides an electric fusion protection device, which combines the circuit breaker and the fuse in series and in parallel, and sets a normally open switch. The fuse cannot participate in the conduction when the normal current is working, and is connected to the fuse circuit when a large current or high voltage fault occurs, thereby solving the problem of breaking the large current or high voltage system and the temperature rise and metallurgical effect of the fuse in series in the circuit. At the same time, the fuse is miniaturized. In this way, the application requirements of the new energy + energy storage system are met, and there is no need to frequently maintain the fusion protection device, which improves the stability of the system and reduces the maintenance cost.

The technical solution of the utility model is as follows:

An electric fusion protection device, comprising at least a circuit breaker, at least one fuse and other components, wherein the circuit breaker comprises at least an insulating housing, at least one repulsive static contact, a moving contact, at least one arc extinguishing chamber, an operating mechanism, a first terminal and a second terminal, at least one normally open switch device is arranged at both ends of the fuse, the normally open switch device and the fuse constitute a normally open fuse device, the two ends of the normally open fuse device are connected between the two repulsive static contacts or between one repulsive static contact and a moving contact or between two repulsive static contacts and a moving contact or between the first terminal and the second terminal or between the first terminal and the moving contact or between the second terminal and the moving contact; the normally open switch device is directly or indirectly driven to close by the moving contact or/and an electromagnetic device

In this way, the fuse does not participate in conduction when operating with normal current, preventing the fuse temperature from fluctuating. The fuse will not produce metallurgical effects, ensuring the reliability and safety of the fuse when breaking fault current, and it has low power consumption, small size and low cost.

In a preferred embodiment, there are at least one or more normally open switch devices connected in series, suitable for connecting a single or multiple fuses; the rated impulse withstand voltage (Uimp) value of the normally open switch device is not less than 7000V, so that the normally open switch device will not be broken down by voltage when it is not connected.

In the above embodiments, the breaking capacity of the circuit breaker is effectively improved.

In a preferred embodiment, the normally open switch device is provided with at least a second static contact and a second moving contact.

In a preferred embodiment, the conductor cross-sectional areas of the repulsive type stationary contact and the moving contact are larger than the conductor cross-sectional areas of the second stationary contact and the second moving contact.

In a preferred embodiment, the rated current value of the fuse is smaller than the rated current value of the circuit breaker.

In a preferred embodiment, the moving contact is a rotary single breakpoint or a rotary double breakpoint.

In a preferred embodiment, the moving contact has at least one contact piece or multiple contact pieces connected in parallel.

In a preferred embodiment, when the movable contact has multiple contact pieces, an arc contact is provided to contact the repulsive static contact before the contact piece, which is suitable for protecting the contact piece from arc erosion when breaking a large current.

In a preferred embodiment, when the moving contact is a rotating double breakpoint, a connecting conductor directly or indirectly connected to the fuse is provided on the moving contact, so that the arc current is transferred to the fuse circuit during a high current fault.

In a preferred embodiment, when the movable contact is a rotating double breakpoint, the connecting conductor is connected to a single contact piece or multiple contact pieces and/or an arc contact in the middle of the movable contact.

In a preferred embodiment, the connection between the connecting conductor and the contact piece and/or the arc contact is a fixed connection or a movable connection.

In a preferred embodiment, a moving contact forced arc-isolating device is provided on the moving contact so that the arc can be rapidly lengthened when a large current fault is to be interrupted.

In a preferred embodiment, the movable contact forced arc isolation device comprises an arc isolation cover and a reset torsion spring for enabling the arc isolation cover to cover the movable contact in a disconnected state, and a limiting boss is provided on the arc isolation cover.

In a preferred embodiment, the limiting boss slides in the limiting hole of the gas-generating material in the arc extinguishing chamber.

In a preferred embodiment, the repulsion type static contact is provided with at least a conductor and an alloy contact, at least a part of the structure of the conductor is U-shaped, and the direction of the current flowing through the conductor provided with the alloy contact is opposite to the direction of the current flowing through the conductor opposite to it; the repulsion type static contact is connected to the first terminal or the second terminal.

In a preferred embodiment, a second connecting conductor directly or indirectly connected to the fuse is provided on the conductor on which the alloy contact is provided, so that the arc current is transferred to the fuse circuit in the event of a high current fault.

In a preferred embodiment, a repulsion type static contact forced arc isolation device is provided on the repulsion type static contact, so that the arc is rapidly elongated when a large current fault is to be interrupted.

In a preferred embodiment, the repulsive static contact forced arc isolation device includes a second arc isolation cover and at least one driving rod for making the second arc isolation cover cover the repulsive static contact when the moving contact is repelled, and the second arc isolation cover is provided with a boss.

In a preferred embodiment, a first hole and a second hole are provided on the driving rod, the first hole is connected to a boss on the second arc isolation cover, and the second hole is connected to a boss provided on the contact piece of the moving contact.

In a preferred embodiment, the normally open switch device is further provided with at least an elastic member.

In a preferred embodiment, the elastic member acts on the second moving contact directly or indirectly, and the elastic member provides a force for the second moving contact to move away from the second static contact.

In a preferred embodiment, the normally open switch device is provided with a multi-link mechanism and a release member, and the release member is unlocked to drive the multi-link mechanism to move, thereby driving the normally open switch device to close.

In a preferred embodiment, a second elastic member is provided on the multi-link mechanism, the second elastic member is connected to the second moving contact, and the second elastic member provides a driving force for the second moving contact to approach the second static contact to achieve closing.

In a preferred embodiment, the release member is movably connected to the multi-link mechanism, and the electromagnetic device or the moving contact directly or indirectly drives the release member to disengage from the multi-link mechanism, so that the multi-link mechanism drives the second moving contact to move toward the second static contact under the drive of the second elastic member and closes with it for conduction.

In a preferred embodiment, the insulation protection device of the normally open switch device is of air type, vacuum type or inert gas filled type.

In a preferred embodiment, a moving contact driving structure is provided between the moving contact and the normally open switch device, and the electromagnetic device is a snap-on electromagnetic mechanism.

In a preferred embodiment, a connecting rod pusher is movably provided around the moving contact, and under the action of the electromagnetic force jointly generated by the moving contact and the repulsive static contact, the moving contact drives the connecting rod pusher to move after being repelled.

In a preferred embodiment, a hook-shaped recessed portion is provided on one end of the connecting rod pusher.

In a preferred embodiment, the connecting rod pusher directly or indirectly drives the second moving contact or the tripping member to move.

In a preferred embodiment, the snap-on electromagnetic mechanism is provided with at least a yoke and an armature, and the yoke and the armature are sleeved on the first terminal and/or the second terminal so that the armature and the yoke are attracted to each other when a large current flows through.

In a preferred embodiment, the snap-on electromagnetic mechanism directly or indirectly drives the normally open switch device to perform a closing movement.

In a preferred embodiment, at least one second driving rod is provided between the snap-fit electromagnetic mechanism and the normally open switch device, and the second driving rod is used to transmit the driving force of the snap-fit electromagnetic mechanism.

In a preferred embodiment, the fuse is set to at least one or more, suitable for various connection methods between the circuit breaker and the fuse, including a single fuse connected in parallel with a single-pole circuit breaker, a single fuse connected in series with one breakpoint and one breakpoint of a moving contact in a single-pole circuit breaker in parallel, and multiple fuses connected in parallel with each breakpoint of a moving contact in a single-pole circuit breaker.

In a preferred embodiment, a second release is connected to the operating mechanism, and the second release is connected to an overcurrent protection driver arranged on the first terminal or the second terminal, and the overcurrent protection driver provides a tripping force for the second release in case of overload and/or short circuit.

In a preferred embodiment, the overcurrent protection driver comprises an electromagnetic release and an alloy material thermal bending mechanism.

In a preferred embodiment, the overcurrent protection driver directly or indirectly drives the second release to operate.

In a preferred embodiment, the normally open switch device is arranged behind the operating mechanism.

In a preferred embodiment, the first terminal and the second terminal are arranged at an angle of 90 degrees to 180 degrees.

In a preferred embodiment, the fuses are arranged on both sides of the operating mechanism.

In a preferred embodiment, the operating mechanism and/or the fuse is covered by at least one integral or separate cover.

In a preferred embodiment, a fuse status indication hole and a controller are provided on the cover.

In a preferred embodiment, the other components are further provided with a secondary terminal, a shunt release, or a combination of one or more of an undervoltage release/a loss of pressure release.

In the above embodiments, the electrical fusion protection device has complete accessories and can realize various protections or signal transmission to achieve intelligence.

In a preferred embodiment, the electric fusion protection device is provided with a mounting device, and when the mounting device is provided as a pair of side plates, it is arranged on both sides of the electric fusion protection device to provide installation and structural support for the electric fusion protection device.

The beneficial effects of the utility model are as follows:

1. The physical characteristics of the fuse will not change during long-term operation: A normally open switch is set at the front or back end of the fuse. The fuse cannot participate in conduction when the normal current is working, so there is no phenomenon of the fuse temperature rising and falling. Therefore, there is no mechanism for the fuse to produce metallurgical effect. Therefore, the characteristics of the fuse will not change during long-term use, ensuring the reliability and safety of the fuse when breaking the fault current.

2. Full current disconnection, no protection dead zone: Circuit breakers are used to disconnect rated, overload current and smaller short-circuit current, fuses are used to disconnect large short-circuit current due to faults, and circuit breakers and fuses provide disconnection protection, covering full current protection.

3. High breaking capacity: The ultimate breaking capacity is determined by the ultimate short-circuit breaking capacity of the fuse, which can reach up to 250kA/DC2500V. Currently, molded case circuit breakers and frame type circuit breakers do not have such a high breaking capacity, which is a global first.

4. Low circuit power consumption: There is no fuse involved in the circuit conduction, only the circuit breaker is involved in the work, and the power consumption in the circuit is only the power consumption of the circuit breaker, so the power consumption is low.

5. Low cost: It saves more than 80% of the cost of high-speed circuit breakers for railways or military hybrid (electronic + electromechanical) circuit breakers. It is even lower than the combination of fuse + disconnector: the market price of a 250kA/DC2500V fuse is more than 5,000 yuan, and one for each positive and negative pole costs more than 10,000 yuan. The fuse used in our fusion protection device only needs less than 60% of the rated current, and the volume is less than 50% of the above fuse. The cost of two fuses is only about 4,000 yuan. In addition, the cost of the circuit breaker is 1,000 yuan higher than the disconnector. In this way, the total cost of the fusion protection device is only about 40% of the combination of fuse + disconnector. Because the fusion device does not have the copper wire connecting bar in the middle of the fuse + disconnector, it saves more than 10KG of copper bars, as well as the cost of the height of the cabinet, installation costs, etc., saving more than 1,000 yuan in costs. Every year, China has more than 100,000 large-scale energy storage and power conversion sets, directly creating value of more than 700 million yuan.

6. High protection accuracy: The protection accuracy of the circuit breaker body or in the power distribution system application is the same, both within ±20%, while the protection accuracy of the fuse in the power distribution system application is above ±30% due to consideration of factors such as environment and temperature rise.

7. High protection level: The fuse is set inside the plastic shell and cannot be touched by human hands.

8. Easy to operate: It can be manually operated more than thousands of times or remotely operated electrically.

9. It is convenient and safe to replace the fuse: after the fuse protection is disconnected, there is a fuse disconnection indicator on the insulating shell, the operating handle is in a separated state, the normally open switch is always in a disconnected state, the withstand voltage reaches more than 3000V, and the circuit breaker and the mechanism are also in a separated state. You only need to open the insulating cover, unscrew the nut, and replace the fuse to complete the replacement work.

10. Complete accessories: It can be equipped with secondary terminals, shunt releases, undervoltage releases, and loss of pressure releases to achieve various protections or intelligent signal transmission, which cannot be achieved on the fuse product.

11. Small size: The volume length of the fusion protection device is only 60% of the fuse + disconnector combination device. The width is the same as or smaller than the disconnector (DC2500 uses four-pole series connection).

12. Save floor space: It can reduce the width of the complete set of cabinets by 1/3, and greatly reduce the size of the container.

13. Save transportation costs: The reduction in width also greatly reduces the area occupied by transportation.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the drawings required for use in the implementation methods will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

FIG1 is a schematic diagram of a disconnector and a fuse connected in series in the prior art;

FIG2 is a schematic structural diagram of an electric fusion protection device according to a first embodiment of the present application;

FIG3 is a schematic diagram of the structure of the circuit breaker and the fuse in parallel in FIG2;

FIG4 is a schematic diagram of the internal structure of the circuit breaker shown in FIG2 ;

FIG5 is a schematic diagram showing the connection between the normally open switch device and the snap-on electromagnetic mechanism in FIG3 ;

FIG6 is a schematic structural diagram of the snap-on electromagnetic mechanism in FIG5 driving the normally open switch device to close;

FIG7 is a schematic diagram of the structure of the moving contact and the repulsive type static contact in FIG4;

FIG8 is a schematic structural diagram of a moving contact forced arc isolation device of the utility model;

FIG9 is a schematic structural diagram of a repulsive contact forced arc isolation device of the utility model;

FIG10 is a schematic diagram of the structure of the unlocking operating mechanism of the current protection driving member of the utility model;

FIG11 is a schematic structural diagram of a second embodiment of the utility model in which a fuse and a circuit breaker are connected in parallel;

FIG12 is a schematic structural diagram of a third embodiment of the utility model in which a fuse and a circuit breaker are connected in parallel;

FIG13 is a schematic structural diagram of an electric fusion protection device according to a fourth embodiment;

FIG14 is a schematic structural diagram of the moving contact in FIG13 driving the moving contact driving structure to drive the normally open switch device to close;

FIG15 is a schematic structural diagram of the moving contact in FIG13 driving the moving contact driving structure to drive the normally open switch device to open;

FIG16 is a schematic structural diagram of a moving contact driving structure of another specific embodiment of the utility model;

FIG17 is a schematic structural diagram of the moving contact driving structure in FIG16 driving the normally open switch device to open;

18 to 23 are schematic diagrams of other embodiments of the electric fusion protection device of the utility model;

FIG24 is a schematic diagram of the structure of the utility model in which a fuse is provided for each level of circuit breaker;

FIG25 is a schematic diagram of the structure of the utility model in which two fuses are arranged in each level of the circuit breaker;

FIG. 26 is a schematic diagram of the structure of the electrical accessories of the present utility model.

DETAILED DESCRIPTION

The features and exemplary embodiments of various aspects of the utility model will be described in detail below. In the detailed description below, many specific details are proposed in order to provide a comprehensive understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without the need for some of these specific details. The following description of the embodiment is only to provide a better understanding of the utility model by illustrating the utility model example. The utility model is by no means limited to any specific configuration and algorithm proposed below, but covers any modification, replacement and improvement of elements, parts and algorithms without departing from the spirit of the utility model. In the accompanying drawings and the following description, known structures and technologies are not shown in order to avoid unnecessary ambiguity to the utility model.

In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

FIG1 shows a schematic diagram of a disconnector + fuse in series according to the prior art. As shown in FIG1 , the disconnector + fuse in series includes an incoming terminal 23 ', a circuit breaker 2 ', a fuse 3 ', and an outgoing terminal 24 '. In this scheme, the circuit breaker 2 ' and the fuse 3 ' are connected in series. The main defect of this scheme is that the disconnector + fuse series circuit is connected, and the fuse 3 ' is always in an energized state. The temperature rise generated by the fuse 3 ' during operation is high and the power consumption is large. In order to solve the temperature rise, it is usually configured to be greater than 170% of the rated current, which will cause the system to have a protection dead zone. In addition, a larger specification fuse 3 ' needs to be selected, which will cause the switch protection device to be larger in size and the fuse 3 ' to be more expensive. In addition, the fuse 3 ' is often energized, which will cause a "metallurgical effect" to cause the fuse 3 ' to melt and the equipment to lose protection.

The reason why the isolating switch + fuse is connected in series in the existing technology is mainly due to the development trend of high voltage and high capacity of new energy equipment, which makes the existing switching electrical appliances unable to effectively disconnect (for example: DC2000V and higher voltage requirements, high short-circuit current up to 250kA). The isolating switch + fuse solution, the isolating switch has the function of disconnection and isolation, which is used for isolation and disconnection such as line maintenance, and the fuse has the ampere-second performance to better disconnect high voltage and large short-circuit fault current.

However, when the disconnector and fuse are used in series, the fuse will have problems such as temperature rise and metallurgical effect. In addition, the large size of the combination switch will further increase the size of the equipment and increase the cost.

With respect to the traditional isolating switch + fuse series structure, according to an embodiment of the present disclosure, an electric fusion protection device is provided. The electric fusion protection device of the embodiment of the present disclosure is further described below with reference to the accompanying drawings.

Example

Figure 2 shows a schematic diagram of the structure of the electric fusion protection device of the present application, Figure 3 shows a schematic diagram of the structure of the circuit breaker and the fuse in parallel in Figure 2, and Figure 4 shows a schematic diagram of the internal structure of the circuit breaker shown in Figure 2. As shown in Figures 2 to 4, the electric fusion protection device includes a circuit breaker 2, a fuse 3 and other components, and the circuit breaker 2 includes an insulating shell 5, a repulsion type static contact 212, a moving contact 211, an arc extinguishing chamber 22, an operating mechanism 4, a first terminal 23, and a second terminal 24. A normally open switch device 26 is provided at one end of the fuse 3, and the normally open switch device 26 and the fuse 3 form a normally open fuse device. The two ends of the normally open fuse device are connected between a repulsion type static contact 212 and a moving contact 211, and the normally open switch device 26 is driven to close by an electromagnetic device. In some embodiments, the first terminal 23 is integrally provided with a repulsion type static contact 212, the second terminal 24 is integrally provided with another repulsion type static contact 212, and the normally open fuse device 26 can be provided between the first terminal 23 and the moving contact, or between the second terminal 24 and the moving contact, and the same technical effect can be achieved.

Please continue to refer to Figure 4. The circuit breaker 2 includes a moving contact 211, a repulsive static contact 212, an arc extinguishing chamber 22 and an operating mechanism 4. The moving contact 211 is a double-breakpoint rotary moving contact. Two repulsive static contacts 212 are provided, one repulsive static contact is connected to the first terminal 23, and the other repulsive static contact is connected to the second terminal 24. Two arc extinguishing chambers 22 are provided, which are respectively arranged on two opposite sides of the moving contact 211. The fuse 3 is arranged on the other side of the moving contact 211, that is, the arc extinguishing chamber 22 and the fuse 3 are arranged along the periphery of the moving contact 211 to form a three-sided surround.

Please continue to refer to Figure 3. One end of the fuse 3 is connected to a second connecting conductor 2122 through a normally open switch device 26. One end of the second connecting conductor 2122 is arranged above the alloy contact 2121 of the repulsive static contact 212. The other end of the fuse 3 is connected to the middle position of the arc contact 2112 of the moving contact 211 through a connecting conductor 2123, forming a parallel connection with one breakpoint of the moving contact 211 and a series connection with another breakpoint. When a short-circuit high current occurs, the fuse 3 circuit mainly starts to disconnect when the moving contact 211 in the circuit breaker 2 begins to disconnect or when the moving contact 211 and the repulsive static contact 212 are disconnected. After the head is opened for a certain distance, it is connected. The distance between the moving contact 211 and the repulsive static contact 212 becomes larger and larger, or the moving contact has been moved to the opening position. The arc generated at the alloy contact 2121 is immediately transferred from the alloy material 2121 to one end of the second connecting conductor 2122. Therefore, the arc is immediately transferred from the second connecting conductor 2122 to the fuse 3 through the normally open switch device 26. The alloy material inside the fuse 3 is quickly melted and cut off the circuit under the erosion of the arc. The arc extinguishing medium inside the fuse 3 can also quickly cool and extinguish the arc, completing the large short-circuit current disconnecting protection action of the electrical fusion protection appliance.

In this embodiment, the electromagnetic device used to drive the normally open switch device 26 is a snap-on electromagnetic mechanism 271. When a current higher than the rated current passes through the electrical fusion protection device, that is, when a large short-circuit current passes through, the snap-on electromagnetic mechanism 271 generates a magnetic field force to drive the normally open switch device 26 to close, thereby connecting the fuse current loop for short-circuit fault protection.

Figure 5 shows a connection diagram of the normally open switch device and the snap-on electromagnetic mechanism in Figure 3. As shown in Figure 5, the normally open switch device 26 is driven by the snap-on electromagnetic mechanism 271 to connect the fuse. The normally open switch device 26 is arranged on one side of the first terminal 23. After the normally open switch device 26 is connected in series with the fuse 3, one end is connected to the moving contact 211, and the other end is connected to the repulsive static contact 212; the normally open switch device 26 is composed of a second static contact 261, a second moving contact 262, an elastic member 263, and a shaft 264. There are two second static contacts 261, one second static contact 261 is arranged on the conductor at one end of the fuse, and the other second static contact is arranged at the end of the second connecting conductor 2122. The snap-on electromagnetic mechanism 271 is at least provided with a yoke 2711, an armature 2712, a second driving rod 2713, a connecting rod 2714, a connecting rod 2715, a shaft 2716, and a shaft 2717; the yoke 2711 and the armature 2712 are sleeved on the first terminal 23, and the second driving rod 2713 is movably connected to the armature 2712; one end of the connecting rod 2714 is movably connected to the second moving contact 262, and the other end is movably connected to one end of the connecting rod 2715 through the shaft 2716; the connecting rod 2715 can rotate around the shaft 2717; the other end of the connecting rod 2715 is movably connected to the second driving rod 2713.

As shown in Figure 5, when the current flowing through the main circuit operates normally within the rated current range, the circuit breaker can perform normal opening and closing operations, the snap-on electromagnetic mechanism 271 does not operate, the second moving contact 262 of the normally open switch device 26 is always in the open state, and the fuse circuit is not connected.

As shown in Figure 6, when a current higher than the rated current flows through the main circuit outlet, the snap-on electromagnetic mechanism 271 will generate an electromagnetic force (magnetic field force), and the electromagnetic force will cause the armature 2712 to move toward the position of the yoke 2711 and attract, and the armature 2712 drives the lower end of the connecting rod 2715 to move to the left through the second driving rod 2713, so that the connecting rod 2715 rotates clockwise along the axis 2717, so that the other end of the connecting rod 2715 will drive the connecting rod 2714 to move to the right, because the connecting rod 2714 is movably connected with the second moving contact 262, so that the second moving contact 262 rotates clockwise, so that the second moving contact 262 is connected with the second static contact 261, so that the normally open switch device 26 is closed and the fuse circuit is connected.

Please continue to refer to FIG. 2 and FIG. 7 , the circuit breaker 2 is provided with a moving contact 211 , a repulsive static contact 212 , an arc extinguishing chamber 22 and a current protection driving member 25 . The moving contact 211 includes at least two contact pieces 2111 extending in opposite directions, and the two repulsive static contacts 212 are respectively arranged on the front and rear sides of the moving contact 211, that is, one of the repulsive static contacts 212 is arranged in front of one of the breakpoints of the moving contact 211, and the other repulsive static contact 212 is arranged behind the other breakpoint of the moving contact 211; the repulsive static contact 212 is at least provided with a conductor and an alloy contact, and at least part of the structure of the conductor is U-shaped, and the direction of the current flowing through the conductor provided with the alloy contact is opposite to the direction of the current flowing through the conductor opposite to it; the repulsive static contact is connected to the first terminal or the second terminal; two arc extinguishing chambers 22 are respectively arranged at the upper and lower ends of the moving contact 211, that is, one arc extinguishing chamber 22 is arranged above one of the breakpoints of the moving contact 211, and the other arc extinguishing chamber 22 is arranged below the other breakpoint of the moving contact 211. The plurality of arc extinguishing grids of the arc extinguishing chamber 22 are arranged along the rotation track of the moving contact 211 .

The moving contact 211 includes a plurality of contact pieces 2111 and an arc contact 2112 disposed in the middle of the plurality of contact pieces 2111. The contact portion between the arc contact 2112 and the alloy contact is higher than the contact portion between the contact pieces 2111 disposed symmetrically on both sides and the alloy contact. The arrangement is such that when the moving contact 211 and the repulsive static contact 212 are closed, the arc contact 2112 can contact the alloy contact 2121 fixed on the repulsive static contact 212 before the contact piece 2111. That is, the arc contact 2112 contacts the alloy contact 2121 before the contact piece 2111; when the moving contact 211 and the repulsive static contact 212 are opened or repelled, the arc contact 2112 can be separated from the alloy contact 2121 fixed on the repulsive static contact 212 after the contact piece 2111, that is, the time when the arc contact 2112 is separated from the alloy contact 2121 is later than the time when the contact piece 2111 is separated from the alloy contact 2121. The arc contact 2112 plays the role of closing first and opening later in the process of opening and closing, and can centrally transfer the arc generated in the process of opening and closing to the arc extinguishing chamber 22 at the upper or lower end of the moving contact and the repulsive static contact.

In this embodiment, the moving contact 211 includes multiple contact pieces in a multi-piece form. In other embodiments, the moving contact can also be set to a single-piece form. The number of contact pieces 2111 on the moving contact 211 can be set to a multi-piece form or a single-piece form according to the size of the rated current.

It should be noted that in the existing known technology, the moving contact 211 can also be arranged in the form of a single breakpoint, and correspondingly, the repulsion type static contact 212 is also provided with a matching one. The present application does not limit the breakpoint form of the moving contact and the number of repulsion type static contacts. Both double breakpoint and single breakpoint contact forms are within the protection scope of the present application.

In this embodiment, the first terminal 23 and the second terminal 24 are arranged at approximately 90 degrees, that is, the first terminal 23 extends from one side of the insulating shell, and the second terminal 24 extends from the other adjacent side, saving space above the fusion protection device 1. In other embodiments, the first terminal and the second terminal can also be arranged at 180 degrees, that is, the first terminal and the second terminal extend from two opposite sides of the insulating shell. This embodiment is only exemplary and is not intended to limit the present invention. The first terminal and the second terminal can be arranged at an angle of 90 to 180 degrees. The flexible arrangement satisfies customers' various wiring methods.

Please refer to Figures 8 to 10. The operating mechanism 4 is a manual opening mechanism. When the rated current or less than the rated current flows through the circuit, the second release 41 on the operating mechanism 4 can be driven by the operating mechanism 4 or by the shunt release 81 to unlock the operating mechanism 4, which can meet the various operation modes of on-site manual operation and remote control electric operation. The operating mechanism 4 can drive the moving contact 211 away from the repulsive static contact 212. When the arc contact 2112 and the alloy contact 2121 begin to separate, the resistance at the connection between the arc contact 2112 and the alloy contact 2121 increases, the temperature rises sharply, and the alloy contact 2121 melts; as the opening distance between the arc contact 2112 and the alloy contact 1212 increases, the melted alloy contact 2121 completes the transformation from the "metal bridge" to the metal phase arc, and finally forms a stable gas phase arc from the metal phase arc.

Please continue to refer to FIG8 . The movable contact 211 is provided with a movable contact forced arc-isolating device 213, which includes an arc-isolating cover 2131 and a reset torsion spring 2132 for enabling the arc-isolating cover 213 to cover the movable contact in the disconnected state. The arc-isolating cover 213 is provided with a limiting boss 21311, which can slide in the gas-producing material limiting hole 221 of the arc-extinguishing chamber 22. The arc-isolating cover 2131 is pivotally mounted on the contact piece 2111. When the movable contact 211 is away from the repulsive static contact 212, the arc-isolating cover 2131 rotates clockwise under the action of the reset torsion spring 2132 until it completely covers the contact piece 2111 and the upper part of the arc contact 2112, thereby cutting off the arc. The movement of the arc isolation cover 2131 is reversible. When the circuit breaker is closed, when the moving contact 211 and the repulsion type static contact 212 are close to each other, the limiting boss 21311 on the arc isolation cover 2131 is installed in the limiting hole 221 of the gas-producing material on the arc extinguishing chamber 22. Under the guidance of the limiting hole 221 of the gas-producing material, the limiting boss 21311 drives the arc isolation cover 2131 to rotate counterclockwise to open the moving contact arc isolation device.

Please continue to refer to Figure 9. The repulsive static contact 212 is provided with a repulsive static contact forced arc-isolating device, and the repulsive static contact forced arc-isolating device includes a second arc-isolating cover 2141, and at least one driving rod 2142 for making the second arc-isolating cover 2141 cover the repulsive static contact 212 when the moving contact is repelled, and the second arc-isolating cover 2141 is provided with a boss 21411, and the driving rod 2142 is provided with a first hole 21421 and a second hole 21422.

The arc shield 2141 is pivotally mounted on the conductor 2120 of the repulsive static contact 212, the first hole 21421 on the driving rod 2142 is pivotally mounted on the boss 21411 on the arc shield 21421, and the second hole 21422 on the driving rod 2142 is pivotally mounted on the boss 2111a on the contact piece 2111. When the moving contact 211 is away from the repulsive static contact 212, the contact piece 2111 drives the driving rod 2142 to move, and the arc shield 2141 moves clockwise under the pull of the moving driving rod 2142 until it completely wraps the alloy contact in the repulsive static contact 212 to cut off the arc. The movement of the arc shield 2141 is reversible. When the switch is closed, when the moving contact 211 and the repulsive static contact 212 are close to each other, the contact piece 2111 drives the movement of the driving rod 2142. The arc shield 2141 moves counterclockwise under the pull of the moving driving rod 2142 to open the arc shield device of the repulsive static contact. When the rated current is interrupted or less than the rated current, the forced arc shield device of the passive contact and the forced arc shield device of the repulsive static contact cut the interrupted arc. Under the effect of the enhanced self-excitation magnetic field generated by the U-shaped structure of the conductor 2120 in the repulsive static contact 211, under the influence of the Lorentz magnetic force, the arc is transferred to the arc extinguishing chamber 22 above the moving contact 211 and the repulsive static contact 212. Under the effect of the segmented cutting and cooling and deionization of the arc extinguishing chamber 22, the arc is quickly extinguished.

Please continue to refer to Figure 10. The current protection driving member 25 in the circuit breaker 2 includes an alloy material heat bending mechanism 252 and an electromagnetic release 251. When the overload current flows in the circuit, the alloy material heat bending mechanism 252 heats up, deforms and bends. As the bending degree of the alloy material heat bending mechanism 252 increases, it finally contacts the second release 41 on the operating mechanism 4, unlocks the operating mechanism 4, and the operating mechanism 4 drives the moving contact 211 to open the gate. The arc extinguishing process of the circuit breaker 2 is the same as the process of breaking the rated current or less than the rated current. When a smaller short-circuit current flows in the circuit, the electromagnetic release 251 attracts and triggers the second release 41, unlocks the operating mechanism 4, and the operating mechanism 4 drives the moving contact 211 to open the gate. Because the smaller short-circuit current flowing in the circuit fails to reach the attraction value of the snap-on electromagnetic mechanism 271 arranged on the first terminal 23, the snap-on electromagnetic mechanism 271 does not operate. The arc extinguishing process of the circuit breaker 2 is the same as the process of breaking the rated current or the current less than the rated current.

When a large short-circuit arc flows through the circuit, the moving contact forced arc isolation device 213, the repulsion type static contact forced arc isolation device 214 and the arc extinguishing chamber 22 in the circuit breaker 2 cannot stretch and split the arc of large energy to extinguish it, and the arc current is extinguished through the fuse 3 connected to the circuit breaker 2. When the arc current passes through the fuse 3, when the current exceeds the set value, the fuse will melt due to the high temperature, thereby cutting off the current and protecting the electrical equipment and lines from damage. The breaking capacity of the electric fusion protection device can also be increased according to the breaking capacity of the fuse 3 to break a short-circuit current of 250kA under a DC voltage of DC2500V.

Only in the process of large short-circuit current protection, the fuse 3 shunts the circuit of the circuit breaker 2, and the fuse 3 melts and breaks the arc. In normal operation, it does not participate in carrying the working current, only the circuit breaker 3 participates in the work, and the power consumption in the circuit is only the power consumption of the circuit breaker, so the power consumption is low; at the same time, the rated current of the fuse 3 can be less than the rated current of the circuit breaker 2, which reduces the production cost, so the cross-sectional area of the second static contact 261 and the second moving contact 262 of the normally open switch device 26 in the circuit of the fuse 3 can also be smaller than the moving contact 211 and the repulsion type static contact 212.

Example

FIG11 shows a schematic diagram of the structure of the second embodiment of the connection between the circuit breaker and the fuse in the electric fusion protection device of the present application. The difference from the first embodiment is that the two ends of the normally open fuse device are connected between two repulsive static contacts, or between the first terminal 23 and the second terminal 24, and the other end of the fuse 3 is connected to the second terminal 24 or another repulsive static contact 212 through a connecting conductor 2123. In the utility model, when the moving contact 211 is a double breakpoint form, the two repulsive static contacts 212 are respectively integrated with the first terminal 23 and the second terminal 24. This arrangement makes the fuse 3 parallel to the two breakpoints of the moving contact 211, and the fuse circuit is completely separated from the circuit breaker circuit. The short-circuit current breaking action process is the same as that of the first embodiment, and will not be repeated here.

Example

FIG12 is a schematic structural diagram of a third embodiment of the connection between a circuit breaker and a fuse in an electric fusion protection device of the present application. The difference from the first embodiment is that the normally open fuse device is arranged between two repulsive static contacts and a moving contact, and two fuses 3 can be arranged on each level of the circuit breaker 2, one of which is arranged in the same manner as in Embodiment 1, and the third connecting conductor 2124 at one end of the other fuse 3 is integrated with the connecting conductor 2123, and connected together to the middle position of the arc contact 2112; the other end of the fuse 3 The fourth connecting conductor 2125 is connected above the alloy contact 2121 on another repulsive type static contact 212. The connecting conductor 2123, the third connecting conductor 2124, and the fourth connecting conductor 2125 can use a copper bus to connect the fuse 3 to the circuit breaker 2, or use a soft connection to connect the circuit breaker 2 to the fuse 3. This arrangement can allow two fuses 3 to be connected in parallel with the two break points of the circuit breaker, respectively, to further enhance the breaking capacity of the product. The short-circuit current breaking action process is the same as that in the first embodiment, and will not be repeated here.

Example

Please refer to Figures 13 to 15. The present application discloses an electric fusion protection device of a fourth embodiment. The difference from the first embodiment is that the normally open switch device of this embodiment is driven to close by the moving contact through the moving contact driving structure 272. As shown in Figure 13, the normally open switch device 26 is arranged on one side of the first terminal 23. After the normally open switch device 26 is connected in series with the fuse 3, one end of the fuse is connected to the moving contact 211 through the moving contact driving structure 272, and the other end is connected to the repulsive static contact 212; the normally open switch device 26 is at least provided with a second static contact 261, a second moving contact 262, an elastic member 263, and a shaft 264, and the moving contact driving structure 272 is at least provided with a connecting rod pusher 27 21. shaft 2722, shaft 2723, support member 2724, shaft 2725 and shaft 2726; one end of the connecting rod pusher 2721 has a hook-shaped recessed portion 2721a, and the other end is movably connected to the second moving contact 262 through the shaft 2723; the shaft 2726 is movably connected to the contact piece 2111 in the moving contact 211; one end of the shaft 2725 is fixed to the rotating shaft in the moving contact 211, and the other end is movably connected to one end of the support member 2724; the other end of the support member 2724 is connected to the shaft 2726; the elastic member 263 is connected to the second moving contact 262, and under the elastic force of the elastic member 263, the second moving contact 262 and the second static contact 261 are kept in a normally open state.

As shown in Figure 13, in this scheme, when the current flowing through the main circuit operates normally within the rated current range, the circuit breaker can perform normal opening and closing operations, the moving contact driving structure 272 does not operate, the second moving contact 262 of the normally open switch device 26 is always in the open state, and the fuse circuit is not connected.

As shown in FIG. 14 , when a current higher than the rated current flows through the main circuit, the repulsive moving contact 211 will be repelled by the electric repulsive force generated together with the repulsive static contact 212, and the contact piece 2111 in the moving contact 211 will rotate counterclockwise along the shaft 2113. At this time, the contact piece 2111 will drive the shaft 2726 to move counterclockwise. Therefore, the rotating shaft on the moving contact 211 does not rotate, and the support member 2724 can only rotate counterclockwise along the shaft 2725 under the drive of the shaft 2726, thereby causing the shaft 2726 to rotate counterclockwise together. As shown in FIG15 , during the rotation process, the shaft 2726 will be lifted in the height direction, so that it can enter the hook-shaped recessed portion 2721a provided on the connecting rod pusher 2721, thereby driving the connecting rod pusher 2721 to move together; because the connecting rod pusher 2721 is connected to the second moving contact 262, driven by the connecting rod pusher 2721, the second moving contact 262 will rotate clockwise along the axis 264, so that the second moving contact 262 contacts the second static contact 261, so that the normally open switch device 26 is closed, as shown in FIG15 , and the circuit of the fuse 3 is connected. During the entire movement process, the repulsive type moving contact 211 is repelled halfway before it starts to drive the second moving contact 262 to perform the closing action. Therefore, the time when the repulsive type moving contact 211 is repelled by the electric repulsion force is earlier than the time when the fuse 3 receives electricity.

When a large current flows through the fuse 3, the fuse inside the fuse 3 melts quickly, cutting off the arc current, thereby playing a protective disconnection role. The disconnection indicator set on the insulating shell will display the disconnection state, which is convenient for prompting replacement. The circuit breaker 2 will also be in a separated state under the action of the electromagnetic release 251, and then the mechanism drives the normally open switch to open; thus, both ends of the fuse 3 are in a disconnected state, and the fuse can be replaced safely and conveniently by simply opening the insulating cover and unscrewing the nut.

In some embodiments, the normally open switch device 26 is provided with a multi-link mechanism 28, as shown in Figures 16 and 17, the multi-link mechanism 28 is provided with a release member 2801, a second elastic member 2802, a shaft 2803, and a shaft 2804; one end of the release member 2801 is movably fixed on the shaft 2803, and the other end is provided with a notch 2801a and a notch 2801b, the notch 2801a is clamped on the second moving contact 262, and the notch 2801b is connected to the shaft 2804 sliding contact; the other end of the shaft 2804 is fixed on the connecting rod pusher 2721; the second elastic member 2802 is hung on the release member 2801, and the initial elastic force of the second elastic member 2802 always keeps the release member 2801 to lock the second moving contact 262, and the second moving contact 262 is always in the open state; the elastic member 263 is hung on the second moving contact 262, and the elastic member 263 is in the energy storage state.

As shown in Figure 16, in this scheme, when the current flowing through the main circuit operates normally within the rated current range, the circuit breaker can perform normal opening and closing actions, the trip member 2801 and the second moving contact 262 are in a locked state, the second moving contact 262 of the normally open switch device 26 is always in an open state, and the fuse circuit is not connected.

As shown in FIG17 , when a current higher than the rated current flows through the main circuit, the moving contact driving structure 272 will be activated, and the connecting rod pusher 2721 will drive the shaft 2804 to move to the left, so that the shaft 2804 will squeeze the notch 2801b and push the release member 2801 to rotate clockwise around the shaft 2803, and the notch 2801a on the release member 2801 will be separated from the second moving contact 262; under the pulling force of the elastic member 263 in the energy storage state, the second moving contact 262 will rotate clockwise along the axis 264, so that the normally open switch device 26 is closed and the fuse circuit is connected. During the entire movement process, the repulsive type moving contact 211 is repelled halfway, and the connecting rod pusher 2721 unlocks the release member, and the second moving contact 262 completes the closing action under the action of the elastic member 263. Therefore, the time when the repulsive type movable contact 211 is repelled by the electric repulsive force is earlier than the time when the fuse 3 receives electricity.

In some embodiments, as shown in Figure 18, the normally open switch device 26 can also be arranged on one side of the second terminal 24. After the normally open switch device 26 is connected in series with the fuse 3, one end is connected to the moving contact 211, and the other end is connected to the repulsive static contact 212.

In some embodiments, as shown in FIG19 , at least one normally open switch device 26 is arranged on one side of the first terminal 23, and at least one normally open switch device 26 is also arranged on one side of the second terminal 24; after the normally open switch device 26 is connected in series with the fuse 3, one end is connected to the moving contact 211, and the other end is respectively connected to the repulsive static contact 212 on the first terminal 23 and the second terminal 24. In this solution, one of the fuse circuits can participate in the protection, or both fuse circuits can participate in the protection at the same time; this dual protection structure can greatly improve accuracy and safety.

In some embodiments, as shown in FIGS. 20 and 21 , the multi-link mechanism 28 may further be provided with a second release member 2805 and a third elastic member 2806, wherein the second release member 2805 is fixed on the second moving contact 262, and a notch 2805a is provided at one end of the second release member 2805; the notch 2805a is clamped on the shaft 2716 in the electromagnet mechanism 271; the third elastic member 2806 is pulled and connected to the lower end of the connecting rod 2715, and the initial tension of the third elastic member 2806 will make the connecting rod 2715 always clamped and locked with the shaft 2716; the elastic member 263 is hung on the second moving contact 262 On; when the second release member 2805 is in the locked state, the second moving contact 262 is in the open state, and the third elastic member 2806 is in the energy storage state; when a current higher than the rated current flows through the main circuit outlet, the electromagnet mechanism 271 will be actuated, and the electromagnet mechanism 271 drives the connecting rod 2715 to rotate clockwise around the axis 2717, so that the axis 2716 will be separated from the notch 2805a; thereby, the second moving contact 262 is unlocked, and under the pulling force of the elastic member 263 in the energy storage state, the second moving contact 262 will rotate clockwise along the axis 264 as a circle, so that the normally open switch device 26 is closed, and the fuse circuit is connected.

In some embodiments, as shown in FIG22 , the normally open switch device 26 can also be arranged on one side of the second terminal 24. After the normally open switch device 26 is connected in series with the fuse 3, one end is connected to the moving contact 211, and the other end is connected to the repulsive static contact 212. The snap-on electromagnetic mechanism 271 is sleeved on the second terminal 24.

In some embodiments, as shown in FIG23, at least one of the normally open switch devices 26 is arranged on one side of the first terminal 23, and at least one of the normally open switch devices 26 is also arranged on one side of the second terminal 24. After the normally open switch device 26 is connected in series with the fuse 3, one end is connected to the moving contact 211, and the other end is connected to the repulsive static contact 212. The yoke 2711 and the armature 2712 are respectively sleeved on the first terminal 23 and the second terminal 24. In this solution, one of the fuse circuits can participate in the protection, and the two fuse circuits can participate in the protection at the same time; this dual protection structure can greatly improve accuracy and safety.

As shown in Figures 24 and 25, in an electric fusion protection device, the circuit breaker 2 can be arranged in single phase or multi-phase, and can be adapted to a variety of AC and DC systems. When the circuit breaker 2 is multi-stage, multiple circuit breakers and fuses are symmetrically arranged on both sides of the operating mechanism 4. The electric fusion protection device includes a pair of mounting side plates 91 for fixing and installing the electric fusion protection device.

As shown in FIG. 26 , an electric fusion protection device of the present application can meet the rated impulse withstand voltage (Uimp) value of not less than 7000V, the operating mechanism 4 or/and the fuse 3 are covered by an integral or split cover 6, and the multi-stage circuit breaker 2 is protected by an insulating shell 5, which increases the stability and insulation performance of the electric fusion protection device, and at the same time improves the integrity of the product appearance. The cover 6 is provided with a state indication hole 61 of the fuse 3 and a controller 7, the state indication hole 61 is used to indicate the fuse state of the fuse 3 and the long delay overload, short delay, instantaneous tripping protection and other characteristic protection settings of the controller 7 (such as voltage protection, current protection, leakage protection and other parameter settings, data display) to realize direct visual observation of the fuse 3 state, the controller 7 improves the intelligence of the fusion protection device, and at the same time ensures that the circuit breaker measurement and protection accuracy reaches ±10%.

As shown in Figures 25 and 26, the electrical fusion protection device of the present application is installed with a secondary terminal 8, a shunt release 81 or an undervoltage release/loss of pressure release 82 or a combination of the above structures. Electrical accessories such as a controller 7 can remotely or locally control signal input and output. The secondary terminal 8 can supply power to the electrical accessories and the electronic controller 7 through a converter.

The utility model can be implemented in other specific forms without departing from its spirit and essential characteristics. The current embodiment is considered to be exemplary rather than restrictive in all aspects, and the scope of the utility model is defined by the appended claims rather than the above description, and all changes falling within the meaning and equivalent scope of the claims are thus included in the scope of the utility model.

Claims (44)

1. An electric fusion protection device, comprising at least a circuit breaker, at least one fuse and an element, wherein the circuit breaker comprises at least an insulating housing, at least one repulsive static contact, a moving contact, at least one arc extinguishing chamber, an operating mechanism, a first terminal and a second terminal, at least one normally open switch device is arranged at both ends of the fuse, the normally open switch device and the fuse constitute a normally open fuse device, the two ends of the normally open fuse device are connected between the two repulsive static contacts or between one repulsive static contact and the moving contact or between two repulsive static contacts and the moving contact or between the first terminal and the second terminal or between the first terminal and the moving contact or between the second terminal and the moving contact; characterized in that: the normally open switch device is directly or indirectly driven to close by the moving contact and/or the electromagnetic device. 2. An electrical fusion protection device as described in claim 1, characterized in that: there are at least one or more normally open switch devices connected in series, suitable for connecting a single or multiple fuses; the rated impulse withstand voltage value of the normally open switch device is not less than 7000V, so that the normally open switch device will not be broken down by voltage when it is not connected. 3. An electric fusion protection device as claimed in claim 1, characterized in that the normally open switch device is provided with at least a second static contact and a second moving contact. 4. An electric fusion protection device as claimed in claim 3, characterized in that the conductor cross-sectional area of the repulsive static contact and the moving contact is larger than the conductor cross-sectional area of the second static contact and the second moving contact. 5. An electric fusion protection device as claimed in claim 1, characterized in that the rated current value of the fuse is smaller than the rated current value of the circuit breaker. 6. An electric fusion protection device as claimed in claim 1, characterized in that the moving contact is a rotary single breakpoint or a rotary double breakpoint. 7. An electric fusion protection device as claimed in claim 6, characterized in that the contact piece of the moving contact is at least one or more pieces connected in parallel. 8. An electric fusion protection device as described in claim 7, characterized in that: when the moving contact has multiple contact pieces, an arc contact is provided to contact the repulsive static contact before the contact piece, which is suitable for protecting the contact piece from arc erosion when disconnecting large currents. 9. An electric fusion protection device as described in claim 6, characterized in that: when the moving contact is a rotating double breakpoint, a connecting conductor directly or indirectly connected to the fuse is provided on the moving contact, so that the arc current is transferred to the fuse circuit during a large current fault. 10. An electric fusion protection device as claimed in claim 9, characterized in that: the connecting conductor is connected to the single contact piece or multiple contact pieces in the middle of the moving contact and/or the arc contact. 11. An electric fusion protection device as claimed in claim 10, characterized in that the connection between the connecting conductor and the contact piece and/or the arc contact is a fixed connection or a movable connection. 12. An electric fusion protection device as claimed in claim 1, characterized in that: a moving contact forced arc isolation device is provided on the moving contact so that the arc can be quickly elongated when a large current fault is to be interrupted. 13. An electric fusion protection device as described in claim 12, characterized in that: the moving contact forced arc isolation device includes an arc isolation cover and a reset torsion spring used to enable the arc isolation cover to cover the moving contact when the arc isolation cover is in a disconnected state, and a limiting boss is provided on the arc isolation cover. 14. An electric fusion protection device as claimed in claim 13, characterized in that the limiting boss slides in the limiting hole of the gas-generating material in the arc extinguishing chamber. 15. An electric fusion protection device as described in claim 1, characterized in that: the repulsion type static contact is at least provided with a conductor and an alloy contact, at least part of the structure of the conductor is U-shaped, and the direction of the current flowing through the conductor provided with the alloy contact is opposite to the direction of the current flowing through the conductor opposite to it; the repulsion type static contact is connected to the first terminal or the second terminal. 16. An electrical fusion protection device as claimed in claim 15, characterized in that: a second connecting conductor directly or indirectly connected to the fuse is provided on the conductor on which the alloy contact is provided, so that the arc current is transferred to the fuse circuit in the event of a large current fault. 17. An electric fusion protection device as claimed in claim 15, characterized in that: a repulsive static contact forced arc-isolating device is provided on the repulsive static contact, so that the arc can be rapidly elongated when a large current fault is to be interrupted. 18. An electric fusion protection device as described in claim 17, characterized in that: the repulsive static contact forced arc isolation device includes a second arc isolation cover, at least one driving rod used to make the second arc isolation cover cover the repulsive static contact when the moving contact is repelled, and the second arc isolation cover is provided with a boss. 19. An electric fusion protection device as described in claim 18, characterized in that: a first hole and a second hole are provided on the driving rod, the first hole is connected to the boss on the second arc isolation cover, and the second hole is connected to the boss provided on the contact piece of the moving contact. 20. An electric fusion protection device as claimed in claim 3, characterized in that: the normally open switch device is at least further provided with an elastic member. 21. An electric fusion protection device as claimed in claim 20, characterized in that: the elastic member acts directly or indirectly on the second moving contact, and the elastic member provides a force for the second moving contact to move away from the second static contact. 22. An electric fusion protection device as claimed in claim 3, characterized in that: the normally open switch device is provided with a multi-link mechanism and a release member, and the release member is unlocked to drive the multi-link mechanism to move, thereby driving the normally open switch device to close. 23. An electric fusion protection device as described in claim 22, characterized in that: a second elastic member is provided on the multi-link mechanism, the second elastic member is connected to the second moving contact, and the second elastic member provides a driving force for the second moving contact to approach the second static contact to achieve closing. 24. An electric fusion protection device as described in claim 23, characterized in that: the release member is movably connected to the multi-link mechanism, and the electromagnetic device or the moving contact directly or indirectly drives the release member to disengage from the multi-link mechanism, so that the multi-link mechanism drives the second moving contact to move toward the second static contact under the drive of the second elastic member and closes with it for conduction. 25. An electric fusion protection device as claimed in claim 1, characterized in that the insulation protection device of the normally open switch device is of air type, vacuum type or inert gas filled type. 26. An electric fusion protection device as claimed in claim 1, characterized in that a moving contact driving structure is arranged between the moving contact and the normally open switch device, and the electromagnetic device is a snap-on electromagnetic mechanism. 27. An electric fusion protection device as described in claim 3, characterized in that: a connecting rod pusher is movably arranged around the moving contact, and under the action of the electromagnetic force generated by the moving contact and the repulsive type static contact, the moving contact is repelled and drives the connecting rod pusher to move. 28. An electric fusion protection device as claimed in claim 27, characterized in that a hook-shaped recessed portion is provided at one end of the connecting rod pusher. 29. An electric fusion protection device as claimed in claim 27, characterized in that the connecting rod pusher directly or indirectly drives the second moving contact or the tripping member to move. 30. An electric fusion protection device as described in claim 26, characterized in that: the snap-on electromagnetic mechanism is at least provided with a yoke and an armature, and the yoke and the armature are sleeved on the first terminal and/or the second terminal so that the armature and the yoke are attracted to each other when a large current flows through. 31. An electric fusion protection device as claimed in claim 26, characterized in that the snap-on electromagnetic mechanism directly or indirectly drives the normally open switch device to perform a closing movement. 32. An electric fusion protection device as described in claim 26, characterized in that: at least one second driving rod is arranged between the snap-type electromagnetic mechanism and the normally open switch device, and the second driving rod is used to transmit the driving force of the snap-type electromagnetic mechanism. 33. An electric fusion protection device as described in claim 1, characterized in that: the fuse is set to at least one or more, suitable for various connection methods between the circuit breaker and the fuse, including a single fuse connected in parallel with a single-pole circuit breaker, a single fuse connected in series with one breakpoint and one breakpoint in parallel with a moving contact in a single-pole circuit breaker, and multiple fuses connected in parallel with each breakpoint of the moving contact in a single-pole circuit breaker. 34. An electric fusion protection device as described in claim 1, characterized in that: a second release is connected to the operating mechanism, and the second release is connected to an overcurrent protection drive component arranged on the first terminal or the second terminal, and the overcurrent protection drive component provides a tripping force for the second release to be overloaded and/or short-circuited. 35. An electric fusion protection device as claimed in claim 34, characterized in that the overcurrent protection drive component has an electromagnetic release and an alloy material thermal bending mechanism. 36. An electric fusion protection device as claimed in claim 34, characterized in that the overcurrent protection driver directly or indirectly drives the second release to operate. 37. An electric fusion protection device as described in claim 1, characterized in that the normally open switch device is arranged behind the operating mechanism. 38. An electric fusion protection device as claimed in claim 1, characterized in that the first terminal and the second terminal are arranged at an angle of 90 degrees to 180 degrees. 39. An electrical fusion protection device as claimed in claim 1, characterized in that the fuse is arranged on both sides of the operating mechanism. 40. An electric fusion protection device as claimed in claim 1, characterized in that the operating mechanism and/or the fuse are covered by at least one integral or separate cover. 41. An electric fusion protection device as claimed in claim 40, characterized in that a fuse status indicator hole and a controller are provided on the cover. 42. An electric fusion protection device as described in claim 1, characterized in that the time when the moving contact is repelled by the electric repulsive force is earlier than the time when the fuse receives electricity. 43. An electric fusion protection device as claimed in claim 1, characterized in that: the element is also provided with a secondary terminal, a shunt release or a combination of one or more of an undervoltage release/loss of pressure release. 44. An electric fusion protection device as described in claim 1, characterized in that: the electric fusion protection device is provided with a mounting device, and when the mounting device is provided as a pair of side panels, it is arranged on both sides of the electric fusion protection device to provide installation and structural support for the electric fusion protection device.