Method for integrated operation and buffering of dc circuit breaker for integrated marine and land multi-terminal dc system
Patent Information
- Application Number
- CN202610820670.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-08
- Publication Date
- 2026-10-09
AI Technical Summary
[0006]本申请的目的在于克服现有技术的不足，提供一种海陆一体多端直流系统用直流断路器操动缓冲一体化方法，旨在解决现有技术中操动机构需额外配置机械缓冲装置、缓冲不可控、能量浪费严重的问题，通过汤姆逊线圈驱动器的加速与减速电磁力时序协同，实现动触头的“电磁缓冲”与操动一体化，同时回收残余能量用于后续重合闸
1、操动缓冲一体化，无需机械缓冲装置：利用汤姆逊线圈驱动器的加速线圈和减速线圈分时放电，电磁力同时承担操动（加速）和缓冲（减速）功能，动触头以接近零速度到达终点，消除了机械冲击和反弹，提高了开关电气寿命和可靠性。
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Figure CN122889623A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flexible DC transmission technology, specifically relating to an integrated method for operating and buffering DC circuit breakers for a multi-terminal DC system that integrates land and sea operations. Background Technology
[0002] A multi-terminal DC system integrating land and sea typically includes offshore converter stations (such as offshore wind power collection stations) and onshore converter stations, connected to form a multi-terminal network via DC submarine cables / land cables. To ensure the safe and reliable operation of the system, DC circuit breakers need to be installed at each DC line port. The core component of a mechanical or hybrid DC circuit breaker is an ultra-fast vacuum switch, whose operating mechanism needs to complete the opening operation within milliseconds to establish a sufficient opening distance to withstand transient breaking voltages. Existing ultra-fast vacuum switches mostly use Thomson coil drivers (TCA) for their operating mechanisms. Their working principle is as follows: a pre-charged capacitor bank discharges to a fixed coil, inducing eddy currents in a metal disk, generating electromagnetic repulsion that drives the moving contact.
[0003] To overcome the severe mechanical impact (speeds exceeding 10 m / s) when the moving contact reaches its endpoint, existing technologies typically incorporate mechanical buffers at the endpoint, such as oil dampers, spring dampers, or rubber pads. However, existing mechanical buffers suffer from the following problems in use: 1) The buffer force is uncontrollable, and the impact peak is still relatively high, which can easily lead to contact rebound; 2) The buffering process consumes kinetic energy, which cannot be recovered; 3) Increased complexity and volume of the mechanism, especially in integrated marine designs where space and weight are limited.
[0004] Furthermore, in integrated land-sea multi-terminal DC systems, DC circuit breakers also need to have reclosing capabilities. Existing solutions typically use separate capacitor banks for opening and closing, resulting in large and costly energy storage units, and the residual energy in the capacitor banks is wasted after opening.
[0005] Therefore, there is an urgent need for a solution that integrates operation and buffering functions, eliminates the need for mechanical buffering devices, and can recover and utilize residual energy, in order to meet the requirements of integrated land and sea multi-terminal DC systems for miniaturization, high efficiency, and high reliability of DC circuit breakers. Summary of the Invention
[0006] The purpose of this application is to overcome the shortcomings of the prior art and provide an integrated operation and buffering method for DC circuit breakers used in multi-terminal DC systems for both land and sea applications. This method aims to solve the problems in the prior art where the operating mechanism requires additional mechanical buffering devices, the buffering is uncontrollable, and energy is wasted. By coordinating the acceleration and deceleration electromagnetic forces of the Thomson coil driver, the "electromagnetic buffering" of the moving contact and the operation are integrated, while the residual energy is recovered for subsequent reclosing.
[0007] The technical problem solved by this application is achieved through the following technical solution: An integrated method for operating and buffering DC circuit breakers in a multi-terminal DC system integrating land and sea, wherein the multi-terminal DC system includes at least one offshore converter station and at least one onshore converter station, and each converter station is connected to form a multi-terminal network through DC lines. Each DC line port is equipped with a DC circuit breaker, and the ultra-fast vacuum switch of the DC circuit breaker uses a Thomson coil driver as the operating mechanism; the upper and lower coils of the Thomson coil driver are arranged opposite to each other along the motion axis, and the moving contact connected by a metal disk is located between the upper and lower coils; During the opening operation, the upward coil first discharges to generate an upward electromagnetic repulsion force, which drives the moving contact to accelerate from the closed position to the open position. When the moving contact moves more than half of the total stroke, the downward coil immediately discharges to generate a downward electromagnetic repulsion force to electromagnetically buffer and decelerate the moving contact, so that the moving contact reaches the opening end point at a speed close to zero. During the closing operation, the reverse voltage remaining in the capacitor bank after the opening operation is used to discharge the lower coil and the upper coil in reverse order, generating electromagnetic forces in opposite directions. This sequentially completes the closing acceleration and electromagnetic buffer deceleration, causing the moving contact to close at a speed close to zero. Thus, the operation and buffering are completed in time by the same electromagnetic mechanism, realizing the integration of operation and buffering.
[0008] Furthermore, the method is implemented through a centralized drive circuit, which includes: First capacitor bank and second capacitor bank; A charging circuit is used to precharge the first capacitor bank and the second capacitor bank to a set positive voltage. First thyristor module group T u-o T d-o The first capacitor group is controlled to discharge to the upward coil and the second capacitor group is controlled to discharge to the downward coil, respectively. Second thyristor module group T d-c T u-c The second capacitor bank is controlled to discharge in reverse to the downward coil and the first capacitor bank is controlled to discharge in reverse to the upward coil, respectively. The controller is used to trigger each thyristor module group according to a preset timing sequence.
[0009] Moreover, after the first capacitor bank discharges during the tripping operation, its voltage becomes reversed, with an amplitude of 40% to 50% of the initial positive voltage. This residual energy is recovered for the closing operation. Similarly, after the second capacitor bank discharges, it generates a reverse residual voltage with an amplitude of 40% to 50% of the initial positive voltage.
[0010] Furthermore, the preset timing of the controller is that the first thyristor module group T is triggered first when the circuit breaker is opened. u-oAfter a delay of Δt1, the first thyristor module group T is triggered. d-o When closing the circuit, the second thyristor module group T is triggered first. d-c After a delay of Δt2, the second thyristor module group T is triggered. u-c The values Δt1 and Δt2 are determined based on the time required for the moving contact to move to half its stroke.
[0011] Moreover, the speed of the moving contact at both the opening and closing ends is less than 0.2 m / s.
[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. Integrated operation and buffering, eliminating the need for mechanical buffering devices: By utilizing the time-sharing discharge of the acceleration and deceleration coils of the Thomson coil driver, the electromagnetic force simultaneously undertakes the functions of operation (acceleration) and buffering (deceleration). The moving contact reaches the endpoint at near-zero speed, eliminating mechanical shock and rebound, and improving the life and reliability of the switching electrical components.
[0013] 2. Energy recovery and utilization to improve efficiency: After the deceleration phase of the circuit breaker is completed, the residual reverse voltage energy in the capacitor bank is recovered for the closing operation. There is no need to configure an additional dedicated capacitor bank for closing, which reduces the total energy storage requirement and improves the operating efficiency.
[0014] 3. Significantly reduced size and cost: The number of capacitor banks is reduced from 4 to 2 (for DC circuit breakers that require reclosing), and the size and cost of the operating mechanism are significantly reduced, making it particularly suitable for offshore platforms.
[0015] 4. Controllable buffering force and strong adaptability: By adjusting the voltage, capacity and discharge sequence of the capacitor bank, the magnitude and duration of the deceleration force can be precisely controlled to adapt to the switching requirements of different strokes and different load qualities. Mechanical buffer devices, on the other hand, cannot be adjusted once they are fixed.
[0016] 5. Simplify system structure and improve reliability: Eliminate mechanical components such as oil buffers and spring buffers, reduce failure points and maintenance workload, and improve the long-term reliability of the integrated land and sea multi-terminal DC system. Attached Figure Description
[0017] Figure 1 This is a configuration diagram of the integrated land-sea multi-terminal DC power transmission system and DC circuit breaker used in this invention. Figure 2 This is a schematic diagram of the hybrid DC circuit breaker structure used in this invention. Figure 3 This is a control circuit diagram for the traditional operating mechanism of a DC circuit breaker. Figure 4 This is a control circuit diagram of the integrated drive and buffer mechanism of the present invention. Detailed Implementation
[0018] The present application will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present application.
[0019] like Figure 1 As shown, an integrated method for operating and buffering a DC circuit breaker in a multi-terminal DC system integrating land and sea is disclosed. The multi-terminal DC system includes at least one offshore converter station and at least one onshore converter station. Each converter station is connected to form a multi-terminal network via DC lines. A DC circuit breaker is installed at the port of each DC line. The ultra-fast vacuum switch of the DC circuit breaker uses a Thomson coil driver as the operating mechanism. Its innovation lies in the fact that the upper and lower coils of the Thomson coil driver are arranged opposite each other along the motion axis, and the metal disk connecting the moving contact is located between the upper and lower coils. During the opening operation, the upward coil first discharges to generate an upward electromagnetic repulsion force, which drives the moving contact to accelerate from the closed position to the open position. When the moving contact moves more than half of the total stroke, the downward coil immediately discharges to generate a downward electromagnetic repulsion force to electromagnetically buffer and decelerate the moving contact, so that the moving contact reaches the opening end point at a speed close to zero. During the closing operation, the reverse voltage remaining in the capacitor bank after the opening operation is used to discharge the lower coil and the upper coil in reverse order, generating electromagnetic forces in opposite directions. This sequentially completes the closing acceleration and electromagnetic buffer deceleration, causing the moving contact to close at a speed close to zero. The speed of the moving contact at both the opening and closing ends is less than 0.2 m / s. Thus, the operation and buffering are completed in time by the same electromagnetic mechanism, realizing the integration of operation and buffering.
[0020] The method is implemented using a centralized driving circuit, which includes: First capacitor bank and second capacitor bank; A charging circuit is used to precharge the first capacitor bank and the second capacitor bank to a set positive voltage. First thyristor module group T u-o T d-o The first capacitor group is controlled to discharge to the upward coil and the second capacitor group is controlled to discharge to the downward coil, respectively. Second thyristor module group T d-c T u-c The second capacitor bank is controlled to discharge in reverse to the downward coil and the first capacitor bank is controlled to discharge in reverse to the upward coil, respectively. The controller is used to trigger each thyristor module group according to a preset timing sequence.
[0021] During the opening operation, after the first capacitor bank finishes discharging, its voltage becomes reversed, with an amplitude of 40% to 50% of the initial positive voltage. This residual energy is recovered for the closing operation. After the second capacitor bank finishes discharging, it also generates a reverse residual voltage with an amplitude of 40% to 50% of the initial positive voltage.
[0022] The controller's preset timing is that when the circuit breaker is opened, the first thyristor module group T is triggered first. u-o After a delay of Δt1, the first thyristor module group T is triggered. d-o When closing the circuit, the second thyristor module group T is triggered first. d-c After a delay of Δt2, the second thyristor module group T is triggered. u-c The values Δt1 and Δt2 are determined based on the time required for the moving contact to move to half its stroke.
[0023] This embodiment considers an integrated onshore and offshore three-terminal flexible DC system, including one offshore converter station A (for wind power integration) and two onshore converter stations B and C. Each converter station's outgoing port is equipped with a DC circuit breaker, requiring a tripping time ≤ 1ms (the moving contact moves to half its travel). This embodiment uses one of the circuit breakers as an example to illustrate the integrated operation and buffering method.
[0024] Integrated tripping operation buffer process: In the initial state, the first capacitor bank C u Second capacitor group C d Both are precharged with voltage, the moving contact is in the closed position (closed with the stationary contact), and the initial distance between the metal disk and the upper coil is s; During the acceleration phase (0 ~ 1 ms), after the controller detects a fault, it triggers thyristor T. u-o The first capacitor group C u Upward coil L u Upon discharge, an upward electromagnetic repulsion is generated between the upper coil and the metal disk, driving the moving contact to accelerate upward. At t = 1 ms, the moving contact has moved to half its full stroke, at which point the first capacitor bank C... u Once the discharge is complete, the voltage on it drops to a negative value.
[0025] During the deceleration (buffering) phase (1 ~ 2 ms), the controller immediately triggers thyristor T. d-o The second capacitor group C d Downward coil L d During discharge, a downward electromagnetic repulsion force is generated between the lower coil and the metal disk, exerting a reverse force on the upward-moving moving contact, thus decelerating it. At t = 2 ms, the moving contact reaches its full stroke (end point), and its speed drops to near zero, achieving an "electromagnetic soft landing" without mechanical impact. At this time, the second capacitor bank C... d The voltage drops to a negative voltage. The holding unit locks the moving contact in the open position.
[0026] The integrated closing operation buffer process includes: waiting for deionization (2 ~ 202 ms), maintaining the open state for approximately 200 ms, and waiting for the fault point to deionize. During the closing acceleration phase (202 ~ 202.94 ms), the controller triggers thyristor T... d-c The second capacitor group C d Downward coil L d Reverse discharge (current direction opposite to that during opening deceleration) generates an upward electromagnetic repulsion force, driving the moving contact to accelerate from the opening position to the closing position. Due to the lower voltage, smaller discharge current, and weaker electromagnetic force, the acceleration is slower. During the closing deceleration (buffering) phase (202.94 ~ 218.1 ms), when the moving contact approaches its end point, the controller triggers thyristor T. u-c The first capacitor group C u Upward coil L u Reverse discharge generates a downward electromagnetic repulsion force, which slows down and buffers the moving contact.
[0027] Finally, the moving contact closes at a near-zero speed at approximately 218.1 ms, achieving an electromagnetic soft landing. The total closing time is approximately 16.1 ms, which is much longer than the opening time, but does not affect the performance of the DC circuit breaker (reclosing does not require rapid operation).
[0028] This invention ensures that the kinetic energy of the moving contact at the end of the opening acceleration phase is completely absorbed by the electromagnetic force of the opening deceleration phase, and the speed of the moving contact approaches zero when it reaches the end point, thus achieving "electromagnetic soft landing". At the same time, after the opening deceleration phase ends, about 40% to 50% of the initial energy (existing in the form of reverse voltage) is still retained in the capacitor bank. This residual energy is recovered for subsequent closing operations, eliminating the need for additional dedicated closing capacitor banks.
[0029] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.
Claims
1. A method for integrated operation and buffering of a DC circuit breaker in a multi-terminal DC system integrating land and sea, wherein the multi-terminal DC system includes at least one offshore converter station and at least one onshore converter station, the converter stations are connected to form a multi-terminal network via DC lines, and a DC circuit breaker is provided at the port of each DC line, wherein the ultra-fast vacuum switch of the DC circuit breaker uses a Thomson coil driver as the operating mechanism; characterized in that: In the Thomson coil driver, the upper and lower coils are arranged opposite each other along the axis of motion, and the metal disk connecting the moving contact is located between the upper and lower coils. During the opening operation, the upward coil first discharges to generate an upward electromagnetic repulsion force, which drives the moving contact to accelerate from the closed position to the open position. When the moving contact moves more than half of the total stroke, the downward coil immediately discharges to generate a downward electromagnetic repulsion force to electromagnetically buffer and decelerate the moving contact, so that the moving contact reaches the opening end point at a speed close to zero. During the closing operation, the reverse voltage remaining in the capacitor bank after the opening operation is used to discharge the lower coil and the upper coil in reverse order, generating electromagnetic forces in opposite directions. This sequentially completes the closing acceleration and electromagnetic buffer deceleration, causing the moving contact to close at a speed close to zero. Thus, the operation and buffering are completed in time by the same electromagnetic mechanism, realizing the integration of operation and buffering.
2. The integrated method for operating and buffering DC circuit breakers in a multi-terminal DC system for both land and sea use according to claim 1, characterized in that: The method is implemented using a centralized driving circuit, which includes: First capacitor bank and second capacitor bank; A charging circuit is used to precharge the first capacitor bank and the second capacitor bank to a set positive voltage. First thyristor module group T u-o T d-o The first capacitor group is controlled to discharge to the upward coil and the second capacitor group is controlled to discharge to the downward coil, respectively. Second thyristor module group T d-c T u-c The second capacitor bank is controlled to discharge in reverse to the downward coil and the first capacitor bank is controlled to discharge in reverse to the upward coil, respectively. The controller is used to trigger each thyristor module group according to a preset timing sequence.
3. The integrated method for operating and buffering DC circuit breakers in a multi-terminal DC system for both land and sea use according to claim 2, characterized in that: During the opening operation, after the first capacitor bank finishes discharging, its voltage becomes reversed, with an amplitude of 40% to 50% of the initial positive voltage. This residual energy is recovered for the closing operation. After the second capacitor bank finishes discharging, it also generates a reverse residual voltage with an amplitude of 40% to 50% of the initial positive voltage.
4. The integrated method for operating and buffering DC circuit breakers in a multi-terminal DC system for both land and sea use according to claim 2, characterized in that: The controller's preset timing is that when the circuit breaker is opened, the first thyristor module group T is triggered first. u-o After a delay of Δt1, the first thyristor module group T is triggered. d-o When closing the circuit, the second thyristor module group T is triggered first. d-c After a delay of Δt2, the second thyristor module group T is triggered. u-c The values Δt1 and Δt2 are determined based on the time required for the moving contact to move to half its stroke.
5. The integrated method for operating and buffering DC circuit breakers in a multi-terminal DC system for both land and sea use according to claim 1, characterized in that: The speed of the moving contact at both the opening and closing ends is less than 0.2 m / s.