A dual repulsion trip unit for a circuit breaker

Abstract

This invention provides a dual-repulsion tripping device for circuit breakers. The device includes an intermediate valve body and two repulsion mechanisms. The two repulsion mechanisms are connected in parallel to the intermediate valve body, and are connected in parallel to the hydraulic operating mechanism of the circuit breaker. When one repulsion mechanism performs a tripping operation, the oil circuits inside the hydraulic operating mechanism and on the other repulsion mechanism are adjusted accordingly. This allows the other repulsion mechanism to perform a tripping operation based on differential principle under oil pressure, thereby realizing the tripping action of the hydraulic operating mechanism. This invention, by using two repulsion mechanisms connected in parallel on the intermediate valve body, ensures that even if one repulsion mechanism fails, the other repulsion mechanism can still trip normally, ensuring the reliability of the tripping operation and meeting the requirements of power transmission systems for independent dual-tripping circuits in low-frequency circuit breakers.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment circuit breaker technology, and more specifically, to a double-repulsion tripping device for circuit breakers. Background Technology

[0002] According to data released by the Global Wind Energy Council (GWEC), the global installed capacity of offshore wind power reached 21.1 GW in 2021, with China accounting for 80% of the new installed capacity, ranking first in the world. The application prospects of offshore wind power in my country are vast. Currently, the development of near-shore wind power resources in my country is nearing completion, and offshore wind power construction is moving towards mid-to-far-shore areas. Due to limitations in the charging current and power of AC submarine cables, power frequency AC transmission is generally only suitable for near-shore wind farms less than 70km from shore and with a capacity of less than 400MW. While flexible DC transmission has advantages such as high transmission efficiency and low line loss, the high cost and large size of MMC (Multi-modal DC transmission) platforms make offshore platform construction difficult, resulting in high prices and operational challenges. Taking a certain project as an example, the total investment in the transmission system was approximately 4.7 billion yuan, of which the cost of the offshore platform was approximately 900 million yuan. The offshore platform has become a bottleneck restricting the development of large-scale deep-sea wind power.

[0003] To address the shortcomings of the above-mentioned power transmission methods in offshore wind power transmission, low-frequency AC transmission system (LFAC) is a new type of power transmission method. By reducing the frequency and increasing the current carrying capacity of the cable, it improves the effective load capacity of the cable and greatly extends the power transmission distance. It does not require the construction of offshore converter stations, which greatly reduces the construction and maintenance costs of the transmission system. It is a new direction for the future development of offshore wind power transmission technology.

[0004] In low-frequency transmission systems, circuit breakers are among the most critical control and protection devices, requiring reliable interruption of short-circuit fault currents. In low-frequency systems, due to the reduced frequency, the current cycle is longer than in power-frequency systems, and the zero-crossing interval is extended, resulting in a significant increase in the arcing time during circuit breaker interruption. Taking a 20Hz low-frequency transmission system as an example, when the frequency drops from 50Hz to 20Hz, the current cycle increases from 20 milliseconds to 50 milliseconds, and the arcing window of the circuit breaker increases from 9 milliseconds to 22.5 milliseconds, causing the longest arcing time to exceed 35 milliseconds. The energy generated by the arc combustion increases by nearly 80% compared to conventional circuit breakers, far exceeding the breaking capacity of existing circuit breakers.

[0005] Based on a 220kV flexible low-frequency transmission demonstration project, the China Electric Power Research Institute, in conjunction with Shandong Taikai High Voltage Switch Co., Ltd., proposed a low-frequency circuit breaker technology route of fast interruption + phase selection control. Fast interruption utilizes fast circuit breakers to significantly reduce the inherent short arcing time and interruption time of circuit breakers, while phase selection technology controls the arcing time of the circuit breaker to be within the ideal arcing time window (close to short arcing), thereby fundamentally solving the problem of long arcing interruption of low-frequency short-circuit current. This technology route has the following advantages: (1) Fast interruption. It can quickly clear faults and better cooperate with fast control and protection and converter valves to enhance the stability of low-frequency transmission systems; (2) High electrical life. Based on fast circuit breakers and phase selection control, the arcing time of the circuit breaker is significantly shortened, the degree of erosion of the circuit breaker is reduced, the electrical life of the circuit breaker is greatly improved (more than doubled), and the maintenance at sea is reduced.

[0006] The original dual repulsion mechanism consists of two repulsion mechanisms connected in series. It has a large moving mass and a high discharge voltage, which is not conducive to the life of the mechanism. Furthermore, it does not support the simultaneous discharge of the two repulsion coils. In engineering, the relay protection device usually issues a tripping command to both repulsion mechanisms at the same time. The repulsion mechanism needs to be able to meet the requirement that the two tripping coils be energized at the same time and drive the repulsion mechanism. As a result, if one of them fails, the whole system cannot achieve the tripping action. Summary of the Invention

[0007] In view of this, the present invention proposes a dual repulsion tripping device for circuit breakers, which aims to solve the problem that in the existing dual repulsion mechanism, the two repulsion mechanisms connected in series need to be able to simultaneously energize and drive the two tripping coils.

[0008] This invention proposes a dual-repulsion tripping device for a circuit breaker. The device includes an intermediate valve body and two repulsion mechanisms. The two repulsion mechanisms are connected in parallel to the intermediate valve body, and are connected in parallel to the hydraulic operating mechanism of the circuit breaker. When one repulsion mechanism performs a tripping operation, the oil circuit inside the hydraulic operating mechanism and on the other repulsion mechanism is adjusted accordingly, so that the other repulsion mechanism performs a tripping operation based on the differential principle under the action of oil pressure, thereby realizing the tripping action of the hydraulic operating mechanism.

[0009] Furthermore, in the aforementioned dual-repulsion tripping device for circuit breakers, the repulsion mechanism includes a main directional valve and an electromagnetic drive assembly; wherein, the power output end of the electromagnetic drive assembly is connected to the valve core of the main directional valve, and is used to drive the valve core to reciprocate under the action of electromagnetic repulsion, so as to open the opening or closing channel on the main directional valve, thereby adjusting the oil circuit inside the hydraulic operating mechanism, so that the hydraulic operating mechanism performs opening and closing actions.

[0010] Furthermore, in the aforementioned dual-repulsion tripping device for circuit breakers, the electromagnetic drive assembly includes: a tripping coil, a closing coil, and an electromagnetic repulsion disk; wherein the tripping coil and the closing coil are arranged side by side and spaced apart; the electromagnetic repulsion disk is disposed between the tripping coil and the closing coil, and the electromagnetic repulsion disk is reciprocatingly disposed through the tripping coil and the closing coil, the tripping coil and the closing coil generating an alternating magnetic field, generating opposing induced eddy currents on the electromagnetic repulsion disk, the magnetic field generated by the eddy currents interacting with the magnetic field generated by the tripping coil or the closing coil to generate electromagnetic repulsion, and under the drive of the electromagnetic repulsion, the electromagnetic repulsion disk moves away from the tripping coil or the closing coil.

[0011] Furthermore, in the aforementioned double-repulsion tripping device for circuit breakers, a fixing rod is provided on the opening coil and the closing coil, which passes through the opening coil and the closing coil. In addition, a limiter is provided on the fixing rod, which is located between the opening coil and the closing coil and is used to limit and fix the opening coil and the closing coil. A fixing plate is provided at one end of the fixing rod for fixing to the main reversing valve.

[0012] Furthermore, in the aforementioned double-repulsion tripping device for circuit breakers, the main directional valve includes: a valve core, a valve seat, and a valve sleeve; wherein, the valve seat is provided with a closing channel and a opening channel; the valve seat is provided with a valve sleeve inside, and the valve core is disposed in the valve sleeve in a reciprocating manner to open the closing channel or the opening channel.

[0013] Furthermore, in the aforementioned double-repulsion tripping device for circuit breakers, the valve seat is provided with a high-pressure connection port, an adjusting connection port, and a low-pressure connection port, which are respectively connected to the corresponding reversing connection ports of the transition valve body for connecting the high-pressure chamber, the adjusting chamber, and the low-pressure oil tank of the hydraulic operating mechanism. When the valve core moves to the closed position, the high-pressure connection port connects with the adjusting connection port to form an open closing channel, so that the pressure in the adjusting chamber is high pressure for closing action. When the valve core moves to the open position, the low-pressure connection port connects with the adjusting connection port to form an open opening channel, so that the pressure in the adjusting chamber is low pressure for opening action.

[0014] Furthermore, in the aforementioned dual-repulsion tripping device for circuit breakers, the valve core is provided with a high-pressure oil circuit inside. One end of the high-pressure oil circuit extends to the end of the valve core and communicates with the interior of the valve sleeve, while the other end is provided with a channel connection port for connecting the high-pressure channel when the valve core is in the open position. This allows the high-pressure hydraulic oil in the high-pressure channel to flow from the high-pressure oil circuit to the outside of the valve core and between one end of the valve core and the valve sleeve. The pressure applied to the valve core by the hydraulic oil between one end of the valve core and the valve sleeve is greater than the closing driving force applied to the valve core by the electromagnetic drive assembly, but less than twice the closing driving force applied to the valve core by the electromagnetic drive assembly. This ensures that the dual-repulsion tripping device can only drive the hydraulic operating mechanism to perform the closing action when both repulsion mechanisms are performing closing operations.

[0015] Furthermore, in the aforementioned double-repulsion tripping device for circuit breakers, the repulsion mechanism is provided with an oil buffer assembly, which serves to buffer the action of the repulsion mechanism.

[0016] Furthermore, in the aforementioned double-repulsion tripping device for circuit breakers, the oil buffer assembly includes: an oil buffer fixing plate, which is disposed on the repulsion mechanism and serves a fixing function; and an oil buffer body, which is disposed on the oil buffer fixing plate and serves a buffering function when the repulsion mechanism is activated.

[0017] Furthermore, in the aforementioned dual repulsion tripping device for circuit breakers, the transition valve body is provided with a set of mechanism connection ports and two sets of reversing connection ports. The two sets of reversing connection ports are arranged in parallel and are respectively connected to the mechanism connection ports to convert the oil circuit into a dual oil circuit, so as to connect to the oil circuits of the two repulsion mechanisms respectively, and then connect the two repulsion mechanisms in parallel to the oil circuit connection ports of the hydraulic operating mechanism.

[0018] The dual-repulsion trip device for circuit breakers provided by this invention, through two repulsion mechanisms connected in parallel on the transition valve body, ensures that even if one repulsion mechanism fails, the other repulsion mechanism can still normally trip, thus ensuring the reliability of tripping. This meets the requirement of power transmission systems for independent dual-tripping circuits in low-frequency circuit breakers and solves the problem in existing dual-repulsion mechanisms where the two repulsion mechanisms connected in series need to be able to simultaneously energize and drive both tripping coils. Furthermore, the parallel structure of this dual-repulsion trip device has a low discharge voltage and can meet the conditions for single-repulsion mechanism discharge and simultaneous discharge of both repulsion mechanisms. In addition, this dual-repulsion trip device, used in the mechanism of low-frequency circuit breakers in low-frequency power transmission systems, achieves rapid response of the circuit breaker through the repulsion mechanism, ensuring the safe and reliable operation of the low-frequency power transmission system. Currently, low-frequency circuit breakers are mainly used in medium-distance offshore wind power transmission lines. In the future, with the large-scale application and gradual maturation of offshore wind power technology, the demand for low-frequency circuit breakers will increase, and dual-repulsion trip devices will also be widely used. Attached Figure Description

[0019] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0020] Figure 1 This is a structural block diagram of a double-repulsion tripping device for a circuit breaker provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the double-repulsion tripping device for a circuit breaker provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the repulsion mechanism in the open position according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the repulsion mechanism in the closed position according to an embodiment of the present invention. Detailed Implementation

[0024] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] See Figures 1 to 4 This figure illustrates a preferred structure of a dual-repulsion tripping device for a circuit breaker provided by an embodiment of the present invention. As shown, the dual-repulsion tripping device includes: an intermediate valve body 1 and two repulsion mechanisms 2; wherein, the two repulsion mechanisms 2 are connected in parallel to the intermediate valve body 1, and are connected in parallel to the hydraulic operating mechanism 3 of the circuit breaker through the intermediate valve body 1, so that when one of the repulsion mechanisms 2 performs a tripping operation, the oil circuit inside the hydraulic operating mechanism 3 and on the other repulsion mechanism 2 is adjusted accordingly, so that the other repulsion mechanism 2 performs a tripping operation based on the differential principle under the action of oil pressure, thereby realizing the tripping action of the hydraulic operating mechanism 3.

[0026] In specific implementation, two repulsion mechanisms 2 are installed side-by-side on the transition valve body 1. The transition valve body acts as an oil circuit switching transition valve, converting the oil circuit of the main cylinder (i.e., the hydraulic operating mechanism 3) with a single main control valve to an oil circuit with two repulsion mechanisms 2. This allows the two repulsion mechanisms 2 to be connected in parallel via the transition valve body 1, enabling both repulsion mechanisms 2 to simultaneously and individually drive the control valve in the hydraulic operating mechanism 3, thus achieving the function of both repulsion mechanisms 2 simultaneously and individually driving the hydraulic operating mechanism 3 to perform a tripping action. In particular, if one repulsion mechanism 2 fails during its tripping operation, the other repulsion mechanism 2 can still trip normally, ensuring the reliability of the tripping and fulfilling the dual tripping requirement. In this embodiment, the dual repulsion tripping device can only drive the hydraulic operating mechanism 3 to perform a closing action when both repulsion mechanisms 2 are performing a closing operation; that is, they must be driven simultaneously to achieve the closing action of the hydraulic operating mechanism 3. Of course, in other embodiments, individual driving is also possible.

[0027] See also Figures 2 to 4 The repulsion mechanism 2 is equipped with an oil buffer assembly 4, which serves to buffer the action of the repulsion mechanism 2 during its operation. Specifically, the oil buffer assembly 4 is located at the tail end of the repulsion mechanism 2 (e.g., ...). Figure 3 (As shown on the right), it acts as a buffer when the repulsion mechanism 2 operates, extending the service life of the repulsion mechanism 2. In this embodiment, each repulsion mechanism 2 can be equipped with an oil buffer assembly 4 to buffer the two repulsion mechanisms 2 respectively.

[0028] See also Figure 1 The transition valve body 1 is provided with one set of mechanism connection ports A and two sets of reversing connection ports B. The two sets of reversing connection ports B are arranged in parallel and are respectively connected to the mechanism connection ports A. This is used to convert the oil circuit into a dual oil circuit, which is then connected to the oil circuits of the two repulsion mechanisms 2, and thus the two repulsion mechanisms 2 are connected in parallel to the oil circuit connection ports of the hydraulic operating mechanism 1. Specifically, the number of each set of mechanism connection ports A and reversing connection ports B is determined according to the actual situation. In this embodiment, there are three of each set, which are respectively connected to the corresponding connection ports.

[0029] See also Figure 2 and Figure 4 The repulsion mechanism 2 includes a main directional valve 21 and an electromagnetic drive assembly 22. The power output end of the electromagnetic drive assembly 22 is connected to the valve core 211 of the main directional valve 21, and is used to drive the valve core 211 to reciprocate under the action of electromagnetic repulsion, so as to open the opening or closing channel on the main directional valve 21, so as to adjust the oil circuit inside the hydraulic operating mechanism 3, so that the hydraulic operating mechanism 3 performs opening and closing actions.

[0030] In practical implementation, the power output end of the electromagnetic drive assembly 22 and the valve core 211 of the main directional valve 21 can be connected by bolts to facilitate the disassembly and replacement of components. The power output end of the electromagnetic drive assembly 22 can drive the valve core 211 along its axial direction (e.g., under the action of electromagnetic repulsion) Figure 3 The valve core 211 moves reciprocally in the horizontal direction (as shown) to move as shown in the figure. Figure 3 At the indicated open position, the open channel can be opened while the close channel is simultaneously closed, thus connecting the regulating chamber in the hydraulic operating mechanism 3 with the low-pressure oil tank. This results in the pressure within the regulating chamber being low, thereby actuating the main valve core of the main control valve in the hydraulic operating mechanism 3 to perform an open operation. The power output of the electromagnetic drive assembly 22 also drives the valve core 211 to move to the position shown. Figure 4 At the closing position shown, the closing channel can be opened and the opening channel can be closed at the same time, realizing the connection between the regulating chamber and the high-pressure chamber in the hydraulic operating mechanism 3, thereby making the pressure in the regulating chamber high pressure, thus driving the main valve core in the main control valve to perform the closing action.

[0031] See also Figure 3 and Figure 4 The main directional valve 21 includes a valve core 211, a valve seat 212, and a valve sleeve 213; wherein the valve seat 212 is provided with a closing channel and a closing channel; the valve seat 212 is provided with a valve sleeve 213 inside, and the valve core 211 is disposed in the valve sleeve 213 in a reciprocating manner to open the closing channel or the closing channel.

[0032] In specific implementation, the valve core 211 can be a two-section split structure, with the two sections fixedly connected as a single movable structure; the valve sleeve 213 is also a two-section split sleeve structure, both fixed on the left and right sides of the valve seat 212 to guide the two-section split structure. The left valve sleeve section can limit the leftward movement distance of the valve core 211 and can also seal the internal cavity. In this embodiment, one end of the valve seat 212 (e.g., Figure 3 The left end (shown) is provided with an end cap 214 for fixing the valve sleeve 213. The valve core 211 is coaxially disposed inside the valve seat 212 and the valve sleeve 213, and is disposed in the valve sleeve 213 in a manner that allows it to reciprocate linearly along the axial direction of the valve seat 212. Under the action of the power output end of the electromagnetic drive assembly 22, it reciprocates directly, thereby opening the closing channel or the opening channel, realizing the reversal of the oil circuit, and thus regulating the pressure in the regulating cavity of the hydraulic operating mechanism 3.

[0033] See also Figure 3 and Figure 4The valve seat 212 is provided with a high-pressure connection port 2121, an adjustment connection port 2122, and a low-pressure connection port 2123, which are respectively connected to the corresponding reversing connection port B of the transition valve body 1, for connecting the high-pressure chamber, the adjustment chamber, and the low-pressure oil tank of the hydraulic operating mechanism 3 respectively; when the valve core 211 moves to the closed position (e.g. Figure 4 When the valve core 211 moves to the open position (as shown), the high-pressure connection port 2121 is connected to the regulating connection port 2122, forming an open closing channel so that the pressure in the regulating cavity is high pressure, so as to perform the closing action; when the valve core 211 moves to the open position (as shown), the high-pressure connection port 2121 is connected to the regulating connection port 2122, forming an open closing channel, ... as to perform the closing action. Figure 3 When (as shown), the low-pressure connection port 2123 is connected to the regulating connection port 2122 to form an open tripping channel, so that the pressure in the regulating cavity is low, so as to perform the tripping action.

[0034] See also Figure 3 The valve core 211 has a high-pressure oil passage 2111 inside, one end of which extends to the end of the valve core 211 (e.g., Figure 4 The left end (as shown) is connected to the interior of the valve sleeve 213, and the other end is provided with a channel connection port for connecting the high-pressure channel when the valve core is in the open position, so that the high-pressure hydraulic oil in the high-pressure channel flows from the high-pressure oil circuit to the outside of the valve core and between one end of the valve core and the valve sleeve, such as... Figure 3 Within the area C shown, the pressure of the hydraulic oil applied to the valve core 211 between one end of the valve core 211 and the valve sleeve 213 (i.e., within area C) is greater than the closing driving force applied to the valve core 211 by the electromagnetic drive assembly 22, but less than twice the closing driving force applied to the valve core 211 by the electromagnetic drive assembly 22. This ensures that the dual-repulsion tripping device can only drive the hydraulic operating mechanism 3 to perform a closing action when both repulsion mechanisms 2 are performing closing operations. In other words, the hydraulic operating mechanism 3 can only perform a closing action when both electromagnetic drive assemblies 22 apply force to the corresponding valve core 211. Of course, the relationship between the closing driving force applied to the valve core 211 by the electromagnetic drive assembly 22 and the pressure of the hydraulic oil applied to the valve core 211 within area C can also be adjusted according to the actual situation. It can achieve closing only with dual drive, or closing with single drive. This embodiment does not impose any limitations on it.

[0035] See also Figure 3 and Figure 4The electromagnetic drive assembly 22 includes: a trip coil 221, a closing coil 222, and an electromagnetic repulsion disk 223; wherein the trip coil 221 and the closing coil 222 are arranged side by side and spaced apart; the electromagnetic repulsion disk 223 is disposed between the trip coil 221 and the closing coil 222, and the electromagnetic repulsion disk 223 is disposed through the trip coil 221 and the closing coil 222 in a reciprocating manner; the trip coil 221 and the closing coil 222 are used to generate an alternating magnetic field, generating reverse induced eddy currents on the electromagnetic repulsion disk 223; the magnetic field generated by the eddy currents interacts with the magnetic field generated by the trip coil 221 or the closing coil 222 to generate an electromagnetic repulsion force; driven by the electromagnetic repulsion force, the electromagnetic repulsion disk 223 moves away from the trip coil 221 or the closing coil 222.

[0036] In specific implementation, the trip coil 221 is located on the left side, and the closing coil 222 is spaced apart on the right side of the trip coil 221. The electromagnetic repulsion disk 223 is coaxially arranged between the trip coil 221 and the closing coil 222, and is movably arranged along the axial direction of the valve core 211 between the trip coil 221 and the closing coil 222. The valve core 211 is slidably inserted through the trip coil 221, and its outer wall is provided with external threads. The left end of the electromagnetic repulsion disk 223 is connected to the valve core 211, and its right end is slidably inserted through the closing coil 222, so as to be buffered by the oil buffer assembly 4 located on the right side of the closing coil 222. Cables are provided on the trip coil 221 and the closing coil 222 for connection to an external control power supply.

[0037] See also Figure 3 and Figure 4 A fixing rod 224 is provided on the opening coil 221 and the closing coil 222. The fixing rod 224 passes through the opening coil 221 and the closing coil 222. A limiter 225 is also provided on the fixing rod 224. The limiter 225 is located between the opening coil 221 and the closing coil 222 and is used to limit and fix the opening coil 221 and the closing coil 222. One end of the fixing rod 224 (e.g., Figure 3 The left end (as shown) is provided with a fixing plate 226 for fixing to the main directional valve 21. Specifically, the fixing rod 224 can be a screw structure. The opening coil 221, closing coil 222, and limit switch 225 pass through the fixing rod 224. There can be multiple fixing rods 224, arranged along the circumference of the fixing rod 224. The left end of the screw can be fixed to one side of the main directional valve 21 (e.g., the left end) with the fixing plate 226. Figure 3(As shown on the right side), it can be fixed to the valve seat 212 to fix the electromagnetic drive assembly 22 to the main directional valve 21. The oil buffer assembly 4 can be fixed to the right end of the fixing rod 224 to buffer the valve core 211 and the electromagnetic repulsion disk 223.

[0038] See also Figure 3 and Figure 4 The oil buffer assembly 4 includes an oil buffer fixing plate 41 and an oil buffer body 42. The oil buffer fixing plate 41 is mounted on the repulsion mechanism 2 for fixing; the oil buffer body 42 is mounted on the oil buffer fixing plate 41 and serves to buffer the movement of the repulsion mechanism 2. Specifically, the oil buffer fixing plate 41 can be fixed to the right end of the fixing rod 224, and the oil buffer body 42 is located on the side of the oil buffer fixing plate 41 facing the valve core 211 (e.g., ...). Figure 3 At the center position (shown on the left), the electromagnetic repulsion disk 223 is buffered. Specifically, the right side of the electromagnetic repulsion disk 223 is slidably inserted through the closing coil 222 and buffered by the oil buffer body 42. In this embodiment, the oil buffer body 42 is threaded, and it can be threadedly connected to the oil buffer fixing plate 41 to adjust the position of the oil buffer body 42. Of course, the oil buffer body 42 can also be connected to the oil buffer fixing plate 41 in other adjustable ways; this embodiment does not impose any limitations on this.

[0039] The working principle of the double repulsion tripping device for circuit breakers is as follows: During the closing operation, the external control power supply energizes the closing coil 222 of the electromagnetic drive assembly 22, generating a pulse current in the closing coil 222. The pulse current generates an alternating magnetic field around the closing coil 222, and induces a reverse eddy current on the electromagnetic repulsion disk 223. The magnetic field generated by the eddy current interacts with the magnetic field generated by the current in the closing coil 222 to generate an electromagnetic force. Driven by the electromagnetic force, the electromagnetic repulsion disk 223 moves to the left, causing the valve core 211 of the main reversing valve 21 to move to the left in the valve sleeve 213 until... Figure 4 At the indicated location, the high-pressure connection port 2121 and the regulating connection port 2122 are connected, while the connection between the regulating connection port 2122 and the low-pressure connection port 2123 is blocked, thereby opening the closing channel of the main directional valve 21 and closing the opening channel, realizing the rapid closing action of the hydraulic operating mechanism 3; when the opening operation is performed, the external control power supply energizes the opening coil 221 of the electromagnetic drive assembly 22. Driven by the electromagnetic repulsion force, the electromagnetic repulsion disk 223 moves to the right, driving the valve core 211 of the main directional valve 21 to move to the right in the valve sleeve 213 until... Figure 3At the indicated location, the passage connecting the high-pressure connection port 2121 and the regulating connection port 2122 is blocked, while the connection between the regulating connection port 2122 and the low-pressure connection port 2123 is opened. This allows the opening channel of the main directional valve 21 to open and the closing channel to close, enabling the hydraulic operating mechanism 3 to perform a rapid opening action. Specifically, when one opening coil 221 is damaged, and the other opening coil 221 is functioning normally, the other opening coil 221 is energized, opening the opening channel of the main directional valve 21. This allows the hydraulic operating mechanism 3 to switch oil circuits. Simultaneously, the oil pressure change in the main directional valve 21 due to the damaged opening coil 221 causes the valve core 211 of the main directional valve 21 to move relative to each other based on the differential principle. This achieves the opening action of both main directional valves 21, ensuring that the hydraulic operating mechanism 3 can also perform a rapid opening action, thereby ensuring the reliability of the opening action.

[0040] In summary, the dual-repulsion trip device for circuit breakers provided in this embodiment, by connecting two repulsion mechanisms 2 in parallel on the transition valve body 1, ensures that even if one repulsion mechanism 2 fails, the other repulsion mechanism 2 can still normally trip, ensuring the reliability of tripping. This meets the requirements of the power transmission system for independent dual-tripping circuits of low-frequency circuit breakers and solves the problem in existing dual-repulsion mechanisms where the two repulsion mechanisms connected in series need to be able to simultaneously energize and drive the repulsion mechanism with both tripping coils. Furthermore, the parallel structure of this dual-repulsion trip device has a low discharge voltage and can meet the conditions for single-repulsion mechanism discharge and simultaneous discharge of both repulsion mechanisms. In addition, this dual-repulsion trip device, used in the mechanism of low-frequency circuit breakers in low-frequency power transmission systems, achieves rapid response of the circuit breaker through the repulsion mechanism 2, ensuring the safe and reliable operation of the low-frequency power transmission system. Low-frequency circuit breakers are currently mainly used in medium-distance offshore wind power transmission lines. In the future, with the large-scale application and gradual maturation of offshore wind power technology, the demand for low-frequency circuit breakers will increase, and dual-repulsion trip devices will also be widely used.

[0041] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0042] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A dual repulsion trip unit for a circuit breaker, comprising: include: The transition valve body and two repulsion mechanisms; among which, The two repulsion mechanisms are connected in parallel to the transition valve body, and are used to connect in parallel to the hydraulic operating mechanism of the circuit breaker through the transition valve body. When one of the repulsion mechanisms performs a tripping operation, the oil circuit inside the hydraulic operating mechanism and on the other repulsion mechanism is adjusted accordingly, so that the other repulsion mechanism performs a tripping operation based on the differential principle under the action of oil pressure, thereby realizing the tripping action of the hydraulic operating mechanism. The repulsion mechanism includes: a main directional valve and an electromagnetic drive assembly; The main directional valve includes: a valve core, a valve seat, and a valve sleeve; wherein... The valve seat is provided with a closing channel and a closing channel; The valve seat is provided with a valve sleeve inside, and the valve core is disposed in the valve sleeve in a reciprocating manner to open the closing channel or the opening channel. The valve core is provided with a high-pressure oil passage inside. One end of the high-pressure oil passage extends to the end of the valve core and is connected to the inside of the valve sleeve. The other end is provided with a channel connection port for connecting the high-pressure channel when the valve core is in the open position, so that the high-pressure hydraulic oil in the high-pressure channel flows from the high-pressure oil passage to the outside of the valve core and between one end of the valve core and the valve sleeve. The pressure of the hydraulic oil applied to the valve core between one end of the valve core and the valve sleeve is greater than the closing driving force applied to the valve core by the electromagnetic drive assembly, but less than twice the closing driving force applied to the valve core by the electromagnetic drive assembly, so that the double repulsion tripping device can drive the hydraulic operating mechanism to perform the closing action only when both repulsion mechanisms are performing the closing operation.

2. The double-repulsion tripping device for a circuit breaker according to claim 1, characterized in that, The power output end of the electromagnetic drive component is connected to the valve core of the main directional valve, and is used to drive the valve core to reciprocate under the action of electromagnetic repulsion, so as to open the opening or closing channel on the main directional valve, thereby adjusting the oil circuit inside the hydraulic operating mechanism, so that the hydraulic operating mechanism can perform opening and closing actions.

3. The dual repel force trip unit for a circuit breaker of claim 2, wherein, The electromagnetic drive assembly includes: a tripping coil, a closing coil, and an electromagnetic repulsion disk; wherein... The opening coil and the closing coil are arranged side by side and spaced apart; The electromagnetic repulsion disk is disposed between the opening coil and the closing coil, and is reciprocatingly disposed between the opening coil and the closing coil. The opening coil and the closing coil generate an alternating magnetic field, which generates opposing induced eddy currents on the electromagnetic repulsion disk. The magnetic field generated by the eddy currents interacts with the magnetic field generated by the opening coil or the closing coil to generate an electromagnetic repulsion force. Driven by the electromagnetic repulsion force, the electromagnetic repulsion disk moves away from the opening coil or the closing coil.

4. The double-repulsion tripping device for a circuit breaker according to claim 3, characterized in that, The opening coil and the closing coil are provided with a fixing rod, which passes through the opening coil and the closing coil. Furthermore, the fixing rod is also provided with a limiter, which is located between the opening coil and the closing coil and is used to limit and fix the opening coil and the closing coil. One end of the fixing rod is provided with a fixing plate for fixing to the main reversing valve.

5. The double-repulsion tripping device for a circuit breaker according to claim 2, characterized in that, The valve seat is provided with a high-pressure connection port, an adjustment connection port and a low-pressure connection port, which are respectively connected to the corresponding reversing connection ports of the transition valve body, for connecting the high-pressure chamber, the adjustment chamber and the low-pressure oil tank of the hydraulic operating mechanism respectively. When the valve core moves to the closed position, the high-pressure connection port is connected to the regulating connection port to form a closed channel in an open state, so that the pressure in the regulating cavity is high pressure, so as to perform the closing action; When the valve core moves to the open position, the low-pressure connection port connects with the regulating connection port to form an open opening channel, so that the pressure in the regulating cavity is low, so as to perform the opening action.

6. The double-repulsion tripping device for a circuit breaker according to any one of claims 1 to 5, characterized in that, The repulsion mechanism is equipped with an oil buffer assembly, which serves to buffer the action of the repulsion mechanism.

7. The dual repel force trip unit for a circuit breaker of claim 6, wherein, The oil buffer assembly includes: An oil buffer fixing plate is installed on the repulsion mechanism to serve a fixing function; The oil buffer body is mounted on the oil buffer fixing plate and is used to buffer the action when the repulsive mechanism is in motion.

8. The double-repulsion tripping device for a circuit breaker according to any one of claims 1 to 5, characterized in that, The transition valve body is provided with a set of mechanism connection ports and two sets of reversing connection ports. The two sets of reversing connection ports are arranged in parallel and are respectively connected to the mechanism connection ports to convert the oil circuit into a dual oil circuit, so as to connect to the oil circuits of the two repulsion mechanisms respectively, and then connect the two repulsion mechanisms in parallel to the oil circuit connection ports of the hydraulic operating mechanism.

Images