An electronic short-circuit protection trip triggering device for DC circuit breakers

Abstract

This invention discloses an electronic short-circuit protection trip triggering device for DC circuit breakers, comprising a fixing screw, an upper fixing cover, an upper buffer pad, a busbar, a lower buffer pad, a lower fixing cover, and a fixing nut. A magnetic yoke, a piezoelectric ceramic plate, and an armature are arranged in a "U" shape and mounted on the busbar, secured by the upper and lower fixing covers, fixing screw, and fixing nut. When a short-circuit current flows through the busbar, an attractive force is generated between the armature and the magnetic yoke, acting on the piezoelectric ceramic plate. Under the positive piezoelectric effect of the piezoelectric ceramic, a certain voltage is generated on both the upper and lower surfaces of the piezoelectric ceramic plate, thereby triggering the electronic trip unit to trip the short-circuit protection and achieve circuit short-circuit protection. This invention utilizes the positive piezoelectric effect of the piezoelectric ceramic in conjunction with an electromagnet to trigger the electronic short-circuit protection trip. It is small in size, simple in structure and installation, and has a fast response. It can be integrated into any DC circuit breaker, avoiding the problems of large size and high heat generation associated with traditional DC circuit breakers using triggering methods such as shunts.

Description

Technical Field

[0001] This invention belongs to the field of low-voltage electrical appliance technology, specifically relating to an electronic short-circuit protection trip triggering device for DC circuit breakers. Background Technology

[0002] A DC circuit breaker is a protective electrical device used in power systems to distribute electrical energy, protect lines, and prevent damage to electrical equipment from overload and short-circuit faults. Short-circuit protection is one of the most important performance characteristics of a circuit breaker. The short-circuit protection systems used in DC circuit breakers are mainly electronic or electromagnetic. Electronic systems monitor whether a short circuit has occurred in the system circuit and then trigger a dedicated electronic trip unit to release the circuit breaker mechanism, thus tripping the circuit breaker. This method offers high protection accuracy and is simple to implement, making it the commonly used method for short-circuit protection in existing circuit breakers. Therefore, the timely and accurate triggering of the electronic short-circuit trip unit is crucial.

[0003] Currently, the short-circuit current protection tripping trigger commonly used in DC circuit breakers is achieved through shunt triggering. However, shunts are usually very large. The size of a shunt with a rated current of 1000A is equivalent to the size of one pole contact in a circuit breaker with a rated current of 1000A. The larger the rated current, the larger the size of the shunt, making it difficult to integrate and install it inside the circuit breaker, resulting in a significant increase in the overall size of the circuit breaker.

[0004] Meanwhile, the shunt itself has internal resistance. The internal resistance of a standard shunt under rated current is usually 50mV or 75mV, which is much greater than the contact resistance of a single-pole contact. This increases the heat generation and temperature rise of the circuit breaker, greatly increasing the design difficulty of the circuit breaker's conductive circuit. In fact, many circuit breakers need to be derated to prevent the temperature rise of the system circuit.

[0005] Furthermore, temperature changes can also affect the internal resistance of the shunt, causing current measurement accuracy to drift, a phenomenon known as temperature drift. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of large size, high heat generation, and significant temperature drift in existing electronic short-circuit protection trip triggering methods for DC circuit breakers, and to provide an electronic short-circuit protection trip triggering device for DC circuit breakers.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows: An electronic short-circuit protection tripping trigger device for a DC circuit breaker, which includes an insulating sleeve sleeved on a busbar and an armature, a piezoelectric ceramic sheet and a yoke installed outside the insulating sleeve. The yoke, the piezoelectric ceramic sheet and the armature form a "mouth" shape. Both upper and lower surfaces of the piezoelectric ceramic sheet have silver-plated layers and are respectively in contact with the armature and the yoke. Above the armature, an upper buffer pad and an upper fixing cover are sequentially installed. Below the yoke, a lower buffer pad and a lower fixing cover are sequentially installed. The upper fixing cover and the lower fixing cover are respectively fixedly installed on the busbar through fixing screws and fixing nuts.

[0008] For the above-mentioned electronic short-circuit protection tripping trigger device for a DC circuit breaker, the piezoelectric ceramic sheet is fixedly installed between the armature and the yoke through slow-drying epoxy glue, with one side bonded to the armature and the other side bonded to the yoke.

[0009] For the above-mentioned electronic short-circuit protection tripping trigger device for a DC circuit breaker, the materials of the upper buffer pad and the lower buffer pad can be silica gel or rubber. After installing the fixing screws and fixing nuts, a pre-tightening force can be applied to the piezoelectric ceramic sheet.

[0010] The beneficial effects of the present invention are as follows:

[0011] The present invention first utilizes the positive piezoelectric effect of the piezoelectric ceramic in cooperation with an electromagnet to achieve the triggering of the electronic short-circuit protection tripping of the DC circuit breaker, and is directly integrally installed on the inlet and outlet rows of any DC circuit breaker contact system without additionally increasing the size of the circuit breaker.

[0012] The present invention belongs to a piezoelectric non-contact short-circuit current protection tripping trigger device, which is small in size, simple in structure and installation method, fast in response, does not require an additional loop resistance, greatly reduces the temperature rise of the main circuit, and can be simply integrally installed into any DC circuit breaker without increasing the volume, avoiding the problems of large volume and high heat generation of traditional circuit breakers using shunt triggers and other triggering methods. At the same time, it is not affected by the temperature change of the main circuit and avoids the temperature drift problem existing in the traditional method.

[0013] The present invention utilizes the positive piezoelectric effect of the piezoelectric ceramic in cooperation with an electromagnet to achieve the triggering of the electronic short-circuit protection tripping of the DC circuit breaker, without increasing the main circuit resistance, greatly reducing the temperature rise of the main circuit, and avoiding the problem of high heat generation caused by the increase of the main circuit resistance in the traditional DC circuit breaker using a shunt trigger to trigger the electronic short-circuit protection tripping. Because the suddenly changed temperature of the main circuit cannot be quickly transmitted to this device, the temperature drift problem existing in the traditional trigger device is avoided. Brief Description of the Drawings

[0014] Figure 1 is the axonometric view of the present invention;

[0015] Figure 2 This is a cross-sectional view illustrating the working principle of the present invention;

[0016] Figure 3 This is a schematic diagram of the piezoelectric ceramic sheet of the present invention;

[0017] Figure 4 This is an exploded view of the present invention.

[0018] The labels on the attached drawings are as follows: 1—fixing screw, 2—upper fixing cover, 3—upper buffer pad, 4—armature, 5—insulating sleeve, 6—busbar, 7—piezoelectric ceramic plate, 8—magnetic yoke, 9—lower buffer pad, 10—lower fixing cover, 11—fixing nut. Detailed Implementation

[0019] To further understand the content of this invention, it will be described in detail with reference to the accompanying drawings and embodiments.

[0020] Reference Figures 1 to 4 As shown, this invention discloses an electronic short-circuit protection tripping trigger device for a DC circuit breaker, comprising a fixing screw 1, an upper fixing cover 2, an upper buffer pad 3, an armature 4, an insulating sleeve 5, a busbar 6, a piezoelectric ceramic plate 7, a magnetic yoke 8, a lower buffer pad 9, a lower fixing cover 10, and a fixing nut 11. The insulating sleeve 5 is fitted onto the busbar 6 for insulation. The magnetic yoke 8, the piezoelectric ceramic plate 7, and the armature 4 form a "U" shape and are mounted on the busbar 6 covered by the insulating sleeve 5. The upper buffer pad 3 and the upper fixing cover 2 are sequentially installed above the armature 4, and the lower buffer pad 9 and the lower fixing cover 10 are sequentially installed below the magnetic yoke 8, and are fixed to the busbar 6 by the fixing screw 1 and the fixing nut 11.

[0021] The piezoelectric ceramic sheet 7 has a silver-plated layer on both the upper and lower surfaces, and is fixedly installed between the armature 4 and the magnetic yoke 8 with a slow-drying epoxy adhesive. One side is bonded to the armature 4, and the other side is bonded to the magnetic yoke 8.

[0022] The upper buffer pad 3 and the lower buffer pad 9 can be made of silicone or rubber, and are respectively installed between the upper fixing cover 2 and the armature 4 and between the lower fixing cover 10 and the magnetic yoke 8. After the fixing screw 1 and the fixing nut 11 are installed, a preload can be applied to the piezoelectric ceramic sheet 7.

[0023] Reference Figure 2When a short-circuit current flows through the busbar 6, an attractive force is generated between the armature 4 and the yoke 8, acting on the piezoelectric ceramic sheet 7. Under the positive piezoelectric effect of the piezoelectric ceramic, a certain voltage is generated on both the upper and lower surfaces of the piezoelectric ceramic sheet 7, thereby triggering the electronic trip unit to trip the short-circuit protection and achieve circuit short-circuit protection. This avoids the problems of large size and high heat generation of traditional DC circuit breakers using triggering methods such as shunts. The piezoelectric non-contact short-circuit protection triggering device is small in size, simple in structure and installation, does not require increasing the circuit resistance, greatly reduces the temperature rise of the main circuit, and can be easily integrated into any DC circuit breaker without increasing the size.

[0024] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some of the application examples. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. An electronic short-circuit protection tripping trigger device for a direct current circuit breaker, characterized by: The utility model relates to a kind of piezoelectric ceramic piece, including the insulating sleeve (5) of being set on female row (6) and the armature (4) installed outside insulating sleeve (5), piezoelectric ceramic piece (7) and magnetic yoke (8), the magnetic yoke (8), piezoelectric ceramic piece (7) and armature (4) are connected into mouth character shape, silver layer is in piezoelectric ceramic piece (7) upper and lower two sides, respectively with armature (4) and magnetic yoke (8) contact, the upper fixed cover (2) and upper buffer pad (3) are successively installed above armature (4), the lower fixed cover (10) and lower buffer pad (9) are successively installed below magnetic yoke (8), the upper fixed cover (2) and lower fixed cover (10) are fixedly installed on female row (6) by fixed screw (1) and fixed nut (11) respectively.

2. The electronic short-circuit protection tripping trigger device for a DC circuit breaker according to claim 1, characterized in that, The piezoelectric ceramic piece (7) is fixedly installed between the armature (4) and the magnetic yoke (8) by slow drying epoxy glue, one side is bonded together with the armature (4), and the other side is bonded together with the magnetic yoke (8).

3. The electronic short-circuit protection tripping trigger device for a DC circuit breaker according to claim 1 or 2, characterized in that, The upper buffer pad (3) and the lower buffer pad (9) are made of silica gel or rubber.

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