Miniature circuit breaker tripping device based on decoupled integration and tripping method

Abstract

The application discloses a micro circuit breaker tripping device and tripping method based on decoupling integration, which comprises a T-shaped moving iron core, L-shaped static iron cores arranged on the two sides of the vertical part of the moving iron core, and gaps between the moving iron core and the two static iron cores, wherein the two static iron cores are oppositely arranged, and the corners of the static iron cores are away from the horizontal part of the moving iron core, a counterforce spring is sleeved on the vertical part of the moving iron core, one end of the counterforce spring is connected with the horizontal part of the moving iron core, the other end of the counterforce spring is connected with the end portions of the two static iron cores, a top rod is connected with the end of the vertical part of the moving iron core away from the horizontal part, and the two static iron cores are wound with electromagnetic coil groups. The tripping device can reduce the volume of the circuit breaker and has high integration.

Description

Technical Field

[0001] This invention belongs to the field of circuit breaker technology, specifically relating to a miniature circuit breaker trip unit based on decoupling integration, and also to a tripping method for the miniature circuit breaker trip unit based on decoupling integration. Background Technology

[0002] With the rapid development of DC power systems, the application of hybrid DC circuit breakers is becoming increasingly widespread, and the performance requirements for their core component, the trip unit, are also increasing. Traditional trip units typically design the functional inductors of each branch of the working circuit and the electromagnetic mechanism that drives the mechanical switch to open as independent wound magnetic components. However, this discrete structure results in a large size, which is not conducive to achieving the miniaturization, weight reduction, and performance optimization of the overall circuit breaker.

[0003] Planar magnetic technology is widely used due to its advantages such as low profile and ease of integration. However, how to combine this planar magnetic technology with electromagnetic tripping functions and the need for decoupling and integrating multiple magnetic circuits to design a highly integrated trip unit structure remains an unsolved problem. Summary of the Invention

[0004] The purpose of this invention is to provide a miniature circuit breaker trip unit based on decoupling integration, which solves the problems of low magnetic circuit integration in existing trip units and large size caused by the discrete structure of branch inductors in hybrid DC circuit breakers.

[0005] Another object of the present invention is to provide a tripping method for a miniature circuit breaker trip unit based on decoupled integration.

[0006] The technical solution adopted in this invention is a decoupled integrated miniature circuit breaker trip unit, including a T-shaped moving iron core, with L-shaped stationary iron cores respectively arranged on both sides of the vertical part of the moving iron core. The two stationary iron cores are arranged opposite each other, and the corners of the stationary iron cores are all far away from the horizontal part of the moving iron core. There is an air gap between the moving iron core and the two stationary iron cores. A reaction spring is sleeved on the vertical part of the moving iron core. One end of the reaction spring is connected to the horizontal part of the moving iron core, and the other end of the reaction spring is connected to the ends of the two stationary iron cores. A push rod is connected to the end of the vertical part of the moving iron core away from the horizontal part. Electromagnetic coil groups are wound on the two stationary iron cores.

[0007] The invention is further characterized by: The electromagnetic coil assembly includes a first coil, a second coil, and a third coil. The first coil is divided into a first sub-winding and a second sub-winding. The first sub-winding and the second coil are wound in the same direction on one of the stationary iron cores, while the second sub-winding and the third coil are wound in opposite directions on the other stationary iron core.

[0008] The first, second, and third coils are all made of copper wires printed on a printed circuit board.

[0009] Both the stationary and moving iron cores are planar magnetic cores made of silicon steel sheets.

[0010] Another technical solution adopted in this invention is a tripping method based on a decoupled integrated miniature circuit breaker trip unit. The process is as follows: The above-mentioned decoupled integrated miniature circuit breaker trip unit is connected to the miniature circuit breaker and the circuit to be protected. During normal operation, the air gap between the stationary iron core and the moving iron core is at its maximum, and the generated electromagnetic attraction force is less than the elastic force of the return spring, so the moving iron core remains in its initial position. When a short circuit fault occurs, the fault current drives the moving iron core to attract towards the stationary iron core, the air gap decreases, and the inductance value of the electromagnetic coil group increases. When the generated electromagnetic attraction force exceeds the elastic force of the return spring, the moving iron core drives the push rod to push the moving contact to separate from the stationary contact, perform mechanical breaking, and realize tripping.

[0011] The invention is further characterized by: The process of connecting the trip unit of the miniature circuit breaker based on decoupling integration to the miniature circuit breaker is as follows: the stationary iron core is fixed to the insulating base of the miniature circuit breaker, and the push rod is aligned with the position of the moving contact of the miniature circuit breaker.

[0012] The process of connecting the trip unit of the miniature circuit breaker based on decoupling integration into the circuit to be protected is as follows: the first coil is connected in series to the main branch of the circuit to be protected, the second coil is connected in series to the current-carrying branch of the hybrid DC circuit breaker, the third coil is connected in series to the transfer branch of the hybrid DC circuit breaker, and the common node of the miniature circuit breaker is connected to the dissipation branch of the hybrid DC circuit breaker.

[0013] The beneficial effects of this invention are: (1) The present invention is based on a decoupled integrated miniature circuit breaker trip unit, which combines planar magnetic core and PCB (Printed Circuit Board) winding technology. The circuit breaker volume is significantly reduced and the height is significantly reduced, realizing a compact planar design, which is conducive to the overall miniaturization of the circuit breaker. Furthermore, the inductance, moving iron core and stationary iron core of multiple branches are integrated into the same magnetic component, thereby greatly improving the integration degree. (2) The present invention is based on a decoupled integrated miniature circuit breaker trip unit. Through the unique L-shaped stationary iron core and T-shaped moving iron core structure and electromagnetic coil winding arrangement, the vertical part of the moving iron core is used as a common low magnetic resistance path, so that the second and third coils connected in series in different branches can achieve magnetic circuit decoupling, ensuring the independence of the inductance parameters of each branch and the working stability, and avoiding mutual interference. (3) The present invention is based on a decoupled integrated miniature circuit breaker trip unit. When a fault occurs, the movement of the moving iron core pushes the contacts through the push rod to achieve rapid mechanical disconnection and the reduction of the air gap causes the inductance of all integrated coils to double, thereby suppressing the fault current. This synergistic effect of mechanical tripping and electromagnetic current limiting can limit the peak fault current earlier and more effectively, and create conditions for rapid commutation of the transfer branch, thereby shortening the total breaking time. (4) The present invention is based on a decoupled integrated miniature circuit breaker trip unit. When applied to a hybrid DC circuit breaker, it can comprehensively improve the short-circuit breaking performance of the circuit breaker, effectively reduce the peak fault current of each branch, reduce the voltage borne during the mechanical switch breaking process, shorten the full breaking time, improve the action response speed of the trip unit and the reliability of mechanical breaking, and extend the electrical and mechanical life of the circuit breaker. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the miniature circuit breaker trip unit based on decoupling integration of the present invention; Figure 2 This is a schematic diagram of the coil winding structure in the decoupled integrated miniature circuit breaker trip unit of the present invention; Figure 3 This is an equivalent magnetic circuit model diagram of the miniature circuit breaker trip unit based on decoupling integration of the present invention; Figure 4 This is a diagram showing the connection relationship between the trip unit and the miniature circuit breaker based on decoupling integration in this invention. Figure 5 Circuit diagram for a miniature circuit breaker connected to the trip unit of this invention applied to a hybrid DC circuit breaker; Figure 6 Circuit diagram of a miniature circuit breaker with a traditional trip unit applied to a hybrid DC circuit breaker; Figure 7 A diagram showing the connection relationship between a traditional trip unit and a miniature circuit breaker; Figure 8 The breaking characteristic diagram of a miniature circuit breaker connected to the trip unit of this invention applied to a hybrid DC circuit breaker; Figure 9 The breaking characteristic diagram of a miniature circuit breaker with a traditional trip unit applied to a hybrid DC circuit breaker.

[0015] In the diagram, 1. stationary iron core, 2. moving iron core, 3. reaction spring, 4. push rod, 5. first coil, 6. second coil, 7. third coil, 8. moving contact, 9. moving iron core A, 10. push rod, 11. coil. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0017] Example 1 This invention is based on a decoupled integrated miniature circuit breaker trip unit, with the structure as follows: Figure 1 As shown, the device includes a T-shaped moving iron core 2. The T-shaped moving iron core 2 includes a horizontal member, with a vertical member connected to the middle of the horizontal member (the horizontal and vertical components are only used to distinguish parts and do not indicate specific positions or directions). L-shaped stationary iron cores 1 are respectively arranged on both sides of the vertical member of the moving iron core 2. The two stationary iron cores 1 are arranged opposite each other, and the corners of the stationary iron cores 1 are all far away from the horizontal member of the moving iron core 2. There is a variable air gap between the moving iron core 2 and the two stationary iron cores 1. A reaction spring 3 is fitted on the vertical part of the core 2. One end of the reaction spring 3 is connected to the horizontal part of the moving iron core 2, and the other end of the reaction spring 3 is connected to the ends of the two stationary iron cores 1. The reaction spring 3 provides an elastic force to move the moving iron core 2 away from the stationary iron core 1. A push rod 4 is connected to the end of the vertical part of the moving iron core 2 away from the horizontal part. The push rod 4 is used to push the moving contact 8 in the miniature circuit breaker to move, so that the moving contact 8 is separated from the stationary contact. Electromagnetic coil groups are wound on the two stationary iron cores 1.

[0018] Example 2 Based on Example 1, such as Figure 2 As shown, the electromagnetic coil assembly includes a first coil 5, a second coil 6, and a third coil 7. The first coil 5 is divided into a first sub-winding and a second sub-winding, and the total number of turns of the first coil 5 is... N 1. The number of turns of the first sub-winding is N 11 The number of turns of the second sub-winding is N 12 , N 11 + N 12 = N 1. The first sub-winding and the second coil 6 are wound in the same direction on one of the stationary iron cores 1, that is, the spiral direction of the first sub-winding and the second coil 6 is the same, so that the magnetic flux generated by the first sub-winding and the second coil 6 is in the same direction, and the magnetic flux generated is superimposed in the same direction. The second sub-winding and the third coil 7 are wound in opposite directions on the other stationary iron core 1, that is, the spiral direction of the second sub-winding and the third coil 7 is opposite, so that the magnetic flux generated by the second sub-winding and the third coil 7 is in opposite directions, and the magnetic flux generated is canceled out in opposite directions. The magnetic circuits of the second coil 6 and the third coil 7 are decoupled through the low magnetic resistance path provided by the vertical part of the moving iron core 2, so that the magnetic circuits of the two branches are independent and do not affect each other when they are working.

[0019] Example 3 Based on Example 2, the first coil 5, the second coil 6 and the third coil 7 are all made of copper wires printed on a printed circuit board. The stationary iron core 1 and the moving iron core 2 are both planar magnetic cores, and silicon steel sheets are used as the material for the planar magnetic cores. Compared with traditional wound magnetic components, the volume is significantly reduced and it is conducive to automated production.

[0020] Example 4 Based on Example 3, the length of the long arm of the two L-shaped magnetic cores of the stationary iron core 1 is 50 mm, and the length of the short arm is 20 mm.

[0021] The vertical part of the moving iron core 2 has a length of 50 mm, and the horizontal part has a length of 65 mm.

[0022] The cross-sectional area of ​​both the moving iron core 2 and the stationary iron core 1 is 250 mm².

[0023] The initial air gap between the moving iron core 2 and the stationary iron core 1 is 5mm, and the remaining air gap after they are fully engaged is 0.2mm.

[0024] The working principle of the trip unit of this invention is explained by the equivalent magnetic path of the decoupled integrated miniature circuit breaker trip unit, specifically as follows: Figure 3 As shown, the equivalent magnetic path includes a first branch, a second branch, and a third branch connected in parallel. The first branch includes half of the magnetic path of the stationary iron core and the transverse component of the moving iron core, and its total magnetic reluctance is... R 2. Air gap magnetic reluctance between the stationary and moving iron cores R g The equivalent magnetomotive force generated by the first sub-winding of the first coil N 11 i 1. The equivalent magnetomotive force generated by the second coil N 2 i 2; The second branch includes the magnetic reluctance of the vertical component of the moving iron core. R 1; The third branch includes half of the magnetic circuit of the stationary iron core and the transverse component of the moving iron core, and its total magnetic reluctance is R 2. Air gap magnetic reluctance between the stationary and moving iron cores R g The equivalent magnetomotive force generated by the second sub-winding of the first coil N 12 i 1. The equivalent magnetomotive force generated by the third coil N 3 i 3; Because the moving iron core 2 and stationary iron core 1 of the entire decoupled integrated miniature circuit breaker trip unit have a symmetrical structure, the magnetic reluctance of the magnetic cores on both sides is equal. During normal operation, the magnetic reluctance includes the air gap and the magnetic core reluctance. During a fault, the moving iron core 2 is attracted, the air gap disappears or becomes extremely small, and the magnetic reluctance is mainly composed of the magnetic core reluctance. Since the permeability of silicon steel sheets is much higher than that of air, the magnetic reluctance of the vertical components of the moving iron core... R 1. Total magnetic reluctance of the transverse components of the stationary and moving iron cores R 2 is much smaller than the magnetic resistance of the air gap between the moving and stationary iron cores. R g Ignoring the magnetic reluctance of the magnetic core, the inductance and mutual inductance of the first coil 5, the second coil 6, and the third coil 7 during a fault are as follows: (1) (2) (3) (4) (5) In equations (1) to (5), L 1 represents the self-inductance of the first coil. L 2 represents the self-inductance of the second coil. L 3 represents the self-inductance of the third coil. M 21 The mutual inductance of the first and second coils, M 31 The mutual inductance between the first and third coils, L 11 The inductance of the first sub-winding of the first coil. L 12 This represents the inductance of the second sub-winding of the first coil, with / / indicating parallel connection. The flux linkage generated by the first sub-winding of the first coil in connection with the second coil. The magnetic flux generated by the second coil in the first sub-winding of the first coil. The flux linkage generated by the second sub-winding of the first coil in connection with the third coil. The magnetic flux generated by the third coil in the second sub-winding of the first coil. i 2 represents the current flowing through the second coil. i 3 represents the current flowing through the third coil. N 1 represents the total number of turns of the first coil. N 11 The number of turns of the first sub-winding. N 12 The number of turns of the second sub-winding. N 2 represents the number of turns of the second coil. N 3 represents the number of turns of the third coil; Taking the inductance of the first coil as an example, the relationship between the inductance and the air gap distance is analyzed by calculating the ratio of the inductance before and after the fault. The expression for the ratio of the inductance before and after the fault is: (6) In the formula, This represents the inductance value of the first coil when the moving iron core is in its initial state. Let be the inductance value of the first coil at a certain moment during the closing process of the moving iron core and the stationary iron core. The air gap magnetic reluctance between the moving and stationary iron cores at a certain moment during the closing process is given. The air gap reluctance is the value of the moving iron core and the stationary iron core in their initial state. This represents the distance between the moving core and the stationary core in their initial state. This represents the distance between the moving core and the stationary core at a certain moment during the closing process. The permeability of free space, For the cross-sectional areas of the moving iron core and the stationary iron core; The above formula shows that the inductance value is inversely proportional to the air gap distance; the shorter the air gap distance, the greater the inductance value. Under normal operation, the distance between the moving iron core and the stationary iron core is the greatest, the self-inductance and mutual inductance of the coil are the smallest, and the impact on the circuit is small. When a fault occurs, the distance between the moving iron core and the stationary iron core gradually shortens, the inductance value of the first coil increases, and thus it can play its role.

[0025] The relationship between the inductance of the second coil, the inductance of the third coil, and the air gap distance is the same as that of the first coil.

[0026] For example, during normal operation, if the initial air gap is 5mm, and the air gap decreases to 0.5mm at a certain moment during the engagement process, the air gap magnetic resistance drops to about one-tenth, then the inductance can increase by nearly ten times. This significant increase in inductance constitutes an active, rapid, and powerful suppression mechanism for fault current.

[0027] Example 5 The present invention relates to a tripping method for a decoupled integrated miniature circuit breaker trip unit, the process of which is as follows: the decoupled integrated miniature circuit breaker trip unit of any one of Examples 2 to 4 is connected to the miniature circuit breaker, and then the miniature circuit breaker connected to the trip unit is connected to the circuit to be protected (that is, the miniature circuit breaker connected to the trip unit is applied to a hybrid DC circuit breaker). The specific process of connecting the decoupled integrated miniature circuit breaker trip unit to the miniature circuit breaker is as follows: (e.g.) Figure 4 As shown, the stationary iron core 1 is fixed to the insulating base of the miniature circuit breaker, and the push rod 4 is aligned with the position of the moving contact of the miniature circuit breaker. The specific process of connecting the miniature circuit breaker with the trip unit to the circuit to be protected is as follows: The topology of the circuit to be protected is as follows: It includes a main branch, one end of which is grounded, and the other end of which is connected to one end of the current-carrying branch, transfer branch, and dissipation branch of the hybrid DC circuit breaker. The other ends of the current-carrying branch, transfer branch, and dissipation branch are all grounded. The main branch includes a power supply. V DC An inductor is connected in sequence on the positive side. L s ,resistance R s ,power supply V DC The negative side is grounded, and an IGBT (Insulated-Gate Bipolar Transistor) is installed on the transfer branch, while an MOV (Metal Oxide Varistor) is installed on the dissipation branch; for example... Figure 5 As shown, the first coil 5 is connected in series in the main branch of the circuit to be protected. Specifically, the first coil 5 is connected in series with resistor R. s The output terminal of the miniature circuit breaker connects the second coil 6 in series to the current-carrying branch of the hybrid DC circuit breaker, and the third coil 7 in series to the transfer branch of the hybrid DC circuit breaker. The common node of the miniature circuit breaker is connected to the dissipation branch of the hybrid DC circuit breaker. When operating normally, the current flowing through the first coil 5 i Current of coils 1 and 6 i Both are relatively small, and the current flowing through the third coil 7 is... i When 3 is 0, the generated electromagnetic attraction force is less than the elastic force of the reaction spring 3 (that is, the generated electromagnetic attraction force is insufficient to overcome the force of the reaction spring 3), and the moving iron core 2 remains in the initial position. At this time, the air gap between the stationary iron core 1 and the moving iron core 2 is the largest. When a short circuit fault occurs, the current rises sharply, and the electromagnetic attraction generated by the coil winding increases accordingly. When the generated electromagnetic attraction exceeds the elastic force of the return spring 3, the fault current drives the moving iron core 2 to attract towards the stationary iron core 1. As the air gap between the moving iron core 2 and the stationary iron core 1 decreases rapidly, the total magnetic reluctance of the magnetic circuit drops sharply, and the inductance of the electromagnetic coil group will increase significantly and play its respective role. This helps to limit the fault current earlier, trigger the power electronic devices in the hybrid DC circuit breaker, and accelerate the commutation speed, thereby shortening the total breaking time. At the same time, the moving iron core 2 drives the push rod 4 to quickly approach the moving contact 8 in the miniature circuit breaker, and finally pushes the moving contact 8 to move, so that the moving contact 8 is quickly separated from the stationary contact, performing mechanical breaking and realizing the protective tripping function.

[0028] Example 6 This embodiment compares the breaking characteristics of a miniature circuit breaker with the trip unit of the present invention applied to a hybrid DC circuit breaker with those of a miniature circuit breaker with a traditional trip unit applied to a hybrid DC circuit breaker, as follows: like Figure 6 As shown, the circuit topology of a traditional trip unit miniature circuit breaker applied to a hybrid DC circuit breaker is as follows: It includes a main branch, one end of which is grounded. The other end of the main branch is connected to one end of each of the current-carrying branch, transfer branch, and dissipation branch of the hybrid DC circuit breaker. The other ends of each of these branches are grounded. The main branch includes a power supply. V DC An inductor is connected in sequence on the positive side. L s ,resistance R s ,power supply V DC The negative side is grounded, and a miniature circuit breaker with a conventional trip unit is installed on the current-carrying branch. An IGBT (Insulated-Gate Bipolar Transistor) is installed on the transfer branch, and an MOV (Metal Oxide Varistor) is installed on the dissipation branch.

[0029] like Figure 7 As shown, the conventional trip unit includes a moving iron core A9, on which a coil 11 is wound. A push rod 10 is provided inside the moving iron core A9, with both ends of the push rod 10 extending out of the moving iron core A9. The moving iron core A9 is located inside a sleeve, which is connected to an insulating base in a miniature circuit breaker via a bracket.

[0030] After replacing the traditional trip unit in the mechanical switching unit of the current-carrying branch of the hybrid DC circuit breaker with the decoupling-integrated trip unit of this invention, as shown in the figure... Figure 8 and 9 As shown, the conduction time of the transfer branch was shortened from 1.80ms to 1.14ms (a reduction of 36.67%), the total breaking time of the entire circuit breaker was shortened from 5.11ms to 2.61ms (a reduction of 48.92%), the peak current of the current-carrying branch decreased from 1641.14A to 1281.09A (a reduction of 21.94%), and the peak current of the transfer branch decreased from 3336.98A to 2195.99A (a reduction of 34.19%). Furthermore, simulation verification showed that when... L 1 / L 2. L 1 / L The larger the value of 3, the better its breaking characteristics.

[0031] This invention integrates the trip unit and multiple branch inductors through a low magnetic reluctance magnetic circuit decoupling method and applies planar inductor technology, resulting in a compact structure and fast response. It effectively improves the breaking performance, power density and reliability of the hybrid DC circuit breaker and can be widely used in various DC power systems that require high-efficiency breaking.

Claims

1. A miniature circuit breaker trip unit based on decoupled integration, characterized in that, The device includes a T-shaped moving iron core (2), and L-shaped stationary iron cores (1) are respectively provided on both sides of the vertical part of the moving iron core (2). The two stationary iron cores (1) are arranged opposite each other and the corners of the stationary iron cores (1) are all far away from the horizontal part of the moving iron core (2). There is an air gap between the moving iron core (2) and the two stationary iron cores (1). A reaction spring (3) is sleeved on the vertical part of the moving iron core (2). One end of the reaction spring (3) is connected to the horizontal part of the moving iron core (2), and the other end of the reaction spring (3) is connected to the ends of the two stationary iron cores (1). A top rod (4) is connected to the end of the vertical part of the moving iron core (2) that is far away from the horizontal part. An electromagnetic coil group is wound on the two stationary iron cores (1).

2. The miniature circuit breaker trip unit based on decoupling integration according to claim 1, characterized in that, The electromagnetic coil group includes a first coil (5), a second coil (6) and a third coil (7). The first coil (5) is divided into a first sub-winding and a second sub-winding. The first sub-winding and the second coil (6) are wound in the same direction on one of the stationary iron cores (1), while the second sub-winding and the third coil (7) are wound in opposite directions on the other stationary iron core (1).

3. The miniature circuit breaker trip unit based on decoupling integration according to claim 2, characterized in that, The first coil (5), the second coil (6) and the third coil (7) are all made of copper wires printed on a printed circuit board.

4. The miniature circuit breaker trip unit based on decoupling integration according to claim 2, characterized in that, Both the stationary iron core (1) and the moving iron core (2) are planar magnetic cores made of silicon steel sheets.

5. A tripping method for a miniature circuit breaker trip unit based on decoupled integration, characterized in that, The process is as follows: The miniature circuit breaker trip unit based on decoupling integration described in any one of claims 2 to 4 is connected to the miniature circuit breaker and the circuit to be protected. During normal operation, the air gap between the stationary iron core (1) and the moving iron core (2) is the largest, and the generated electromagnetic attraction force is less than the elastic force of the reaction spring (3). The moving iron core (2) remains in the initial position. When a short circuit fault occurs, the fault current drives the moving iron core (2) to attract towards the stationary iron core (1), the air gap decreases, and the inductance value of the electromagnetic coil group increases. When the generated electromagnetic attraction force exceeds the elastic force of the reaction spring (3), the moving iron core (2) drives the push rod (4) to push the moving contact to separate from the stationary contact, perform mechanical breaking, and realize tripping.

6. The tripping method for a miniature circuit breaker trip unit based on decoupled integration according to claim 5, characterized in that, The process of connecting the trip unit of the miniature circuit breaker based on decoupling integration to the miniature circuit breaker is as follows: the stationary iron core (1) is fixed to the insulating base of the miniature circuit breaker, and the top rod (4) is aligned with the position of the moving contact of the miniature circuit breaker.

7. The tripping method for a miniature circuit breaker trip unit based on decoupled integration according to claim 5, characterized in that, The process of connecting the trip unit of the miniature circuit breaker based on decoupling integration into the circuit to be protected is as follows: the first coil (5) is connected in series to the main branch of the circuit to be protected, the second coil (6) is connected in series to the current-carrying branch of the hybrid DC circuit breaker, the third coil (7) is connected in series to the transfer branch of the hybrid DC circuit breaker, and the common node of the miniature circuit breaker is connected to the dissipation branch of the hybrid DC circuit breaker.

Images