Parameter design method for transmission device of vacuum circuit breaker operating mechanism and vacuum arc-extinguishing chamber

Abstract

The application discloses a kind of vacuum circuit breaker operating mechanism and vacuum arc-extinguishing chamber transmission device parameter design method, comprising the following steps: S1, the transmission device between vacuum circuit breaker operating mechanism and vacuum arc-extinguishing chamber is drawn into mechanism movement sketch and carries out motion analysis;S2, the installation position of vacuum circuit breaker operating mechanism, the center position of mechanism output crank arm rotation and the starting position and rotation angle of mechanism output crank arm rotation are determined;S3, the installation position of vacuum arc-extinguishing chamber, contact opening and the position parameter of its connecting link are determined;S4, under the above known conditions, draw design drawing.The application can meet the requirements of contact opening, contact stroke, contact pressure, so that the transmission of operating mechanism and vacuum arc-extinguishing chamber is matched, the electrical performance of vacuum circuit breaker meets the requirements, realizes the normal action of vacuum circuit breaker closing and opening.

Description

Technical Field

[0001] This invention relates to a transmission device connecting the operating mechanism of a vacuum circuit breaker to a vacuum interrupter, and more particularly to a parameter design method for simulating motion of the transmission device connecting the operating mechanism of a vacuum circuit breaker to a vacuum interrupter. Background Technology

[0002] Vacuum circuit breakers are the most important control and protection equipment in power plants, substations and power systems. Their function is to close, carry and interrupt current under normal circuit conditions, and to close, carry and interrupt current under abnormal circuit conditions (such as short circuit conditions) within a specified time.

[0003] 1. Tripping (current interruption): For the circuit breaker mechanism, when the tripping coil of the operating mechanism is energized, the tripping iron core is attracted, causing the locking of the operating mechanism to be released. Under the action of the contact spring and the tripping spring, the moving contact of the vacuum interrupter chamber moves quickly, and the moving and stationary contacts separate rapidly, achieving the purpose of interrupting the current, and the circuit breaker trips. For a vacuum interrupter, when the moving and stationary contacts open under the action of the operating mechanism, an electric arc is generated between the contacts. Due to the high insulation strength of the high vacuum and the rapid diffusion of charged particles generated by the electric arc in the extremely rarefied gas, and because the contacts are designed with a special shape, a magnetic field (transverse or longitudinal magnetic field) is generated when current passes through. Under the action of this magnetic field, the electric arc rotates at high speed along the tangential direction of the contact surface, preventing the contacts from overheating. The metal vapor and charged particles in the arc combustion process are adsorbed and condensed by the shield during the intense diffusion, which reduces the temperature of the contacts and reduces the burn-off of the contacts. The electric arc is extinguished when the current naturally crosses zero, and the dielectric strength between the contacts is rapidly restored, completing the opening action of the vacuum circuit breaker and cutting off the current.

[0004] 2. Closing (Maintaining Current): For the circuit breaker mechanism, when the closing coil of the operating mechanism is energized, the closing core is attracted. Under the action of the energy storage (closing) spring, the moving contact of the vacuum interrupter moves rapidly through the crank arm and connecting rod, and the moving and stationary contacts quickly contact each other, achieving the purpose of closing the current and closing the circuit breaker. For the vacuum interrupter, when the moving and stationary contacts close under the action of the operating mechanism, the moving contact moves rapidly, shortening the distance between the moving and stationary contacts. When the distance between the moving and stationary contacts is shortened to a certain extent, the electrical gap between the contacts is broken down, and an electric arc is generated between the contacts. When the moving contact touches the stationary contact, the contact can no longer move forward. At this time, the electric arc between the contacts may be extinguished (generally referring to a very small current). Under the action of the contact compression spring, the contact pressure between the moving and stationary contacts increases until it reaches the design value, completing the closing action and closing the current. Another scenario involves pre-breakdown occurring before the moving contact touches the stationary contact. An arc is generated between the contacts, and the moving contact has sufficient force to resist the electrodynamic force (generally referring to a large current, such as the closing short-circuit current) to prevent it from retracting. At the moment of contact, under the action of the contact compression spring, the contact pressure suddenly increases to the pre-pressure value to prevent closing bounce and resist the electrodynamic repulsion. At this time, the arc between the contacts is extinguished, ensuring a good initial contact condition. As the contact stroke increases, the contact pressure between the contacts gradually increases. When the contact stroke ends, the contact pressure reaches the design value, completing the closing action and connecting the current. If the closing speed is too low, the pre-breakdown time is long, the arc exists for a long time, and the electrical wear on the contact surface is large, even causing the contacts to weld together and reduce the electrical life of the arc-extinguishing chamber. However, if the speed is too high, closing bounce is likely to occur, the output power of the operating mechanism also needs to be increased, and the mechanical impact on the arc-extinguishing chamber and the whole machine is large, affecting the reliability and mechanical life of the product.

[0005] The design of vacuum circuit breakers is extremely complex. The design of the transmission device connecting its operating mechanism and the vacuum interrupter is fundamental to meeting the requirements of contact opening distance, contact stroke, and contact pressure. If the design parameters of this part do not meet the requirements, it will cause a mismatch between the operating mechanism and the vacuum interrupter. If the mechanical characteristic parameters of the vacuum circuit breaker do not meet the requirements, it will cause a series of problems, ultimately leading to the failure of the electrical performance of the vacuum circuit breaker to meet the requirements, resulting in the failure of the vacuum circuit breaker to close or open. In this case, the vacuum circuit breaker, as the most important control and protection equipment in power plants, substations, and power systems, will lose its function. Summary of the Invention

[0006] The purpose of this invention is to provide a parameter design method for the operating mechanism and transmission device of a vacuum circuit breaker, which can meet the requirements of contact opening distance, contact stroke, and contact pressure, so that the transmission of the operating mechanism and the vacuum interrupter are matched, the electrical performance of the vacuum circuit breaker meets the requirements, and the normal closing and opening operation of the vacuum circuit breaker is realized.

[0007] The objective of this invention is achieved through the following technical measures: a method for designing parameters of a vacuum circuit breaker operating mechanism and a vacuum interrupter transmission device, characterized by comprising the following steps:

[0008] S1. Draw a simplified diagram of the transmission device between the vacuum circuit breaker operating mechanism and the vacuum interrupter and perform motion analysis.

[0009] S2. Determine the installation position of the vacuum circuit breaker operating mechanism, the center position of the rotation of the mechanism output crank arm, and the starting position and rotation angle of the mechanism output crank arm.

[0010] S3. Determine the installation location of the vacuum interrupter, the contact opening distance, and the position parameters of its connecting rods;

[0011] S4. Under the known conditions described above, draw the design diagram:

[0012] (1) Determine the length of the connecting guide rod of the vacuum interrupter, which is the distance from the connecting end of the moving contact of the vacuum interrupter to the center of the hinge of the connecting guide rod, and draw the fixed hinge point, the position of the connecting guide rod and the linear guide device on the drawing;

[0013] (2) Draw the position of the crank fixed hinge point on the figure, and determine the rotation radius of the crank, the rotation radius of the rotating connecting rod, and the hinge center length at both ends of the rotating connecting rod of the crank-slider-connecting rod linear mechanism.

[0014] (3) Preliminarily confirm the position of the circuit breaker drive shaft and the length of its drive crank arm, determine the total length of the hinge center of the transverse drive linkage, draw the position of the linear guide device on the drawing, and confirm the position of the rotation center of the bidirectional drive crank arm.

[0015] (4) The transverse transmission link consists of a variable length section and a constant length section with a central hinge. The length of the constant length section is determined, and the center length of the variable length section is determined when the circuit breaker is closed or opened. The contact stroke of the circuit breaker must meet the maximum contact stroke, and the margin for further compression of the spring when the circuit breaker is closed is determined.

[0016] (5) Determine the rotation angle α of the bidirectional transmission crank arm around the transmission main shaft of the circuit breaker mechanism, and rotate α / 2 symmetrically to the left and right of the vertical line passing through the center of rotation;

[0017] (6) The output crank arm of the vacuum circuit breaker operating mechanism and the bidirectional transmission crank arm on the main transmission shaft of the circuit breaker mechanism form a planar four-bar linkage. Given the rotation angle of the output crank arm, the rotation angle of the bidirectional transmission crank arm, and the hinge center length of the bidirectional transmission crank arm, the hinge center length of the connecting rod and the hinge center length of the output crank arm are obtained, thus completing the parameter design of the transmission device.

[0018] This invention satisfies the requirements for contact opening distance, contact stroke, and contact pressure, ensuring that the operating mechanism and the vacuum interrupter's transmission are matched, and that the electrical performance of the vacuum circuit breaker meets the requirements, thus enabling the vacuum circuit breaker to operate normally during closing and opening. This invention effectively solves the connection problem between the vacuum circuit breaker's operating mechanism and the vacuum interrupter, ensuring that the opening distance and contact stroke of the vacuum circuit breaker are within a certain range and adjustable. Simultaneously, by adjusting the output power and other structural parameters of the vacuum circuit breaker's operating mechanism in conjunction with the contact pressure requirements, it satisfies the mechanical characteristic parameters of the circuit breaker, such as average closing speed, average opening speed, closing bounce time, asynchrony between closing and opening, closing and opening time, main circuit DC resistance, and cumulative allowable wear thickness of moving and stationary contacts. Furthermore, this invention facilitates motion analysis and mechanical calculations of vacuum circuit breakers, providing a theoretical design basis for product component design, pointing a clear direction for prototype manufacturing and assembly debugging, improving the level and efficiency of designers, accelerating the development of new products, and facilitating the serialization of different voltage levels, current levels, and short-circuit breaking current levels.

[0019] Based on the above, the present invention can be fine-tuned. When the contact opening distance, contact stroke, and contact contact pressure of the circuit breaker cannot meet the design requirements, the contact opening distance can be changed by changing the length of the guide rod connected to the vacuum interrupter. At the same time, the contact stroke, contact contact pressure, and contact pressure will also change accordingly. The magnitude of the data change is related to the size of the contact opening distance, and the data must be within the design tolerance range.

[0020] In step S4(4) of this invention, the theoretical design considers that the contact stroke is ≥4mm to meet the maximum contact stroke, and also considers the margin for further compression of the spring when the switch is closed. The theoretical design margin of 1 to 2mm is appropriate.

[0021] In step S4(4) of this invention, the conformity of specific parameters is confirmed during prototype debugging by fine-tuning the opening distance and contact stroke.

[0022] Compared with the prior art, the present invention has the following significant effects:

[0023] (1) The present invention can meet the requirements of contact opening distance, contact stroke and contact pressure, so that the operating mechanism and the transmission of the vacuum interrupter are matched, the electrical performance of the vacuum circuit breaker meets the requirements, and the normal closing and opening operation of the vacuum circuit breaker is realized.

[0024] (2) This invention can effectively solve the connection between the operating mechanism of a vacuum circuit breaker and the vacuum interrupter, so that it can meet the following requirements: the opening distance and contact stroke of the vacuum circuit breaker are within a certain range and can be adjusted. At the same time, in combination with the requirements of contact pressure, the output power of the operating mechanism of the vacuum circuit breaker can be increased or decreased and other structural parameters can be modified to meet the mechanical characteristic parameters of the circuit breaker, such as average closing speed, average opening speed, closing bounce time, asynchrony of closing and opening, closing and opening time, DC resistance of the main circuit, and cumulative allowable wear thickness of moving and stationary contacts.

[0025] (3) This invention is beneficial for the motion analysis and mechanical calculation of vacuum circuit breakers, provides a theoretical design basis for the design of product components, points out a clear direction for prototype trial production and assembly debugging, improves the level and efficiency of designers, accelerates the development speed of new products, and makes it easy to achieve serialization of different voltage levels, different current levels and different short-circuit breaking current levels. Attached Figure Description

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 This is a schematic diagram of the operating mechanism of the 10kV vacuum circuit breaker according to Embodiment 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the vacuum interrupter installation structure according to Embodiment 1 of the present invention;

[0029] Figure 3 This is a schematic diagram of the 10kV vacuum circuit breaker structure according to Embodiment 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the simulated closing and opening motion of the vacuum circuit breaker operating mechanism and the transmission device of the vacuum interrupter chamber in Embodiment 1 of the present invention.

[0031] Figure 5 This is a schematic diagram of the closing simulation motion of the vacuum circuit breaker operating mechanism and the vacuum arc extinguishing transmission device in Embodiment 1 of the present invention;

[0032] Figure 6 This is a schematic diagram of the simulated opening motion of the vacuum circuit breaker operating mechanism and the transmission device of the vacuum interrupter chamber in Embodiment 1 of the present invention.

[0033] Figure 7 This is a schematic diagram of the simulated closing and opening motion of the operating mechanism and the transmission device of the vacuum interrupter in Embodiment 2 of the present invention.

[0034] Figure 8 This is a schematic diagram of the simulated closing and opening motion of the operating mechanism and the transmission device of the vacuum interrupter of the 40.5kV vacuum circuit breaker in Embodiment 3 of the present invention.

[0035] In the diagram: 1-Vacuum circuit breaker operating mechanism, 2, h-Mechanism output crank arm, 3-Connecting rod, 4-Mechanism transmission main shaft, 5, e-Variable rod (variable length part), 6-Contact spring, 7-Mounting bracket, 8-Guide connecting rod (constant length part), 9-Bracket, 10, b-Crank, 11, c-Rotating connecting rod, 12-Guide rod, 13-Moving contact, 14-Stationary contact, 15-Vacuum interrupter chamber; a-Connecting guide rod, d-First connecting rod, f-Bidirectional transmission crank arm, f1-Lower crank arm, f2-Upper crank arm, g-Second connecting rod, O, P, Q-Fixed hinge points, M, N-Linear guide device. Detailed Implementation

[0036] Example 1

[0037] like Figure 3 As shown, when the 10kV vacuum circuit breaker is in the closed state, the vacuum circuit breaker operating mechanism 1 rotates through the mechanism output crank arm 2, outputting closing power and driving the entire linkage transmission mechanism to move. The mechanism output crank arm 2, the connecting rod 3, and the rotating crank arm on the mechanism transmission main shaft 4 form a planar four-bar linkage. The output crank arm 2 of the mechanism is the driving rod, which drives the planar four-bar linkage to move, that is, drives the main shaft 4 of the mechanism to rotate 30 degrees. In other words, the crank arm at the lower end of the main shaft 4 of the mechanism rotates 30°, and the crank arm rotates 30°. It rotates 15° symmetrically in the vertical direction, and converts the arc of the crank arm rotation into an approximate linear motion through the variable rod 5 and the guide connecting rod 8. This drives the crank-slider connecting rod linear mechanism composed of crank 10, rotating connecting rod 11 (one end is hinged to the guide connecting rod 8 and the other end is hinged to the guide rod 12), and bracket 9 to move. The approximate horizontal linear motion is converted into vertical linear motion, that is, the guide rod 12 makes a vertical linear motion. The guide rod 12 is fixedly connected to the moving contact 13, that is, the moving contact 13 makes a vertical linear motion. The moving contact 13 moves upward and contacts the stationary contact 14, and the circuit breaker closes. Conversely, the moving contact 13 moves downwards and disengages from the stationary contact. When the contact opening distance of the vacuum circuit breaker reaches the specified value, the circuit breaker trips. The contact spring 6 is designed to have a considerable pre-compression even when in the tripped position, providing pre-pressure. In the actual structure, the contact spring 6 ensures that during the closing process, when the moving contact 13 has not yet touched the stationary contact 14 and pre-breakdown occurs, the moving contact has sufficient force to resist the electrodynamic force and prevent it from retracting backward. At the moment of contact, the contact pressure suddenly increases to the pre-pressure value to prevent closing bounce, which is sufficient to resist the electrodynamic repulsion and ensures a good initial contact condition. As the contact stroke advances, the contact pressure between the contacts gradually increases, reaching the design value at the end of the contact stroke. The contact stroke does not include the pre-compression range of the closing spring; it is actually the second compression stroke of the closing spring. The mounting bracket 7 supports the circuit breaker operating mechanism and the vacuum interrupter mounting structure and is equipped with a guide sleeve to guide the guide rod 8.

[0038] like Figure 1 As shown, the operating mechanism of the vacuum circuit breaker is a known modular design, and the output rotation angle of its output crank arm is 32°. The hinge center length of the crank arm is confirmed according to the actual design.

[0039] like Figure 2 As shown, when the circuit breaker is closed, the stationary contact 14 and the moving contact 13 inside the vacuum interrupter 15 are in contact. When the circuit breaker is opened, the stationary contact 14 and the moving contact 13 need to be separated by a certain distance, which is called the contact gap. The contact gap of a 10kV vacuum circuit breaker is between 8 and 10 mm, that is, 9 ± 1 mm.

[0040] like Figures 4-6 As shown, the present invention provides a parameter design method for a vacuum circuit breaker operating mechanism and a vacuum interrupter transmission device, comprising the following steps:

[0041] S1. Draw a simplified kinematic diagram of the transmission device between the vacuum circuit breaker operating mechanism and the vacuum interrupter, with the length unit being mm, and perform kinematic analysis.

[0042] S2. Determine the installation position of the vacuum circuit breaker operating mechanism, the center position of the rotation of the mechanism output crank arm h (fixed hinge point O), the starting position and rotation angle of the mechanism output crank arm, and the rotation angle of the mechanism output crank arm h is approximately 32°.

[0043] S3. Determine the installation location of the vacuum interrupter, the contact opening distance, and the position parameters of its connecting rods. The contact opening distance is 9mm.

[0044] S4. Under the conditions described above, draw the design using drafting software or on paper:

[0045] (1) Determine the length of the connecting guide rod a of the vacuum interrupter according to the structural design requirements. That is, the distance from the moving contact connection end of the vacuum interrupter to the hinge center of the connecting guide rod is 108mm. Draw the fixed hinge point O, the position of the connecting guide rod a, and the linear guide device M on the drawing. The guide device M restricts the connecting guide rod a to only perform vertical linear movement.

[0046] (2) According to the structural design requirements, the moving contact of the vacuum interrupter moves in a linear motion up and down. To ensure the linear motion of the moving contact, the motion principle of the crank-slider-connecting rod linear mechanism meets the design requirements. The fixed hinge point Q of the crank-slider-connecting rod linear mechanism is located on the extension line of the connecting guide rod of the vacuum interrupter. Draw the position of the fixed hinge point Q of the crank. To ensure that the rotation radius of the linear motion crank b and the rotating connecting rod c are equal, the rotation radius (hinge center length) of the crank b of the crank-slider-connecting rod linear mechanism is determined to be 44mm, the rotation radius (hinge center length) of the rotating connecting rod c is 44mm, and the hinge center length at both ends of the rotating connecting rod c is 88mm.

[0047] (3) According to the structural design requirements, the transverse transmission link moves linearly left and right. The approximate position of the circuit breaker transmission main shaft and the approximate length of its transmission crank arm can be determined. The total length of the hinge center of the transverse transmission link is determined to be 379mm. The position of the linear guide device N is drawn. From this, the rotation center position of the bidirectional transmission crank arm f can be determined, namely: fixed hinge point P.

[0048] (4) According to structural design requirements, the transverse transmission link can be divided into a variable-length part (variable link e) and a constant-length part (first link d), connected by a hinge. The first link d reciprocates linearly according to the motion trajectory of the crank-slider connecting rod linear mechanism, and its length is 255mm. The hinge center length of the variable link e is approximately 124mm when closed and approximately 129.6mm when open. The contact stroke and contact pressure of the circuit breaker are designed on the variable-length part. The transverse transmission link is hinged to reduce the influence of the reciprocating linear motion deformation of the transverse transmission link and reduce the transverse... Regarding the frictional force of the transmission link, it should be noted that: in the theoretical design, the contact stroke is considered to be ≥4mm to meet the maximum contact stroke, and the margin for further compression of the spring during closing (related to the latching amount of the vacuum circuit breaker operating mechanism 1) should also be considered. The theoretical design margin of 1-2mm is appropriate, which can be calculated simply, such as: 129.6-124=5.6mm≥3.5±0.5mm. The compliance of specific parameters can be resolved by fine-tuning the opening distance and contact stroke during prototype debugging. Fine-tuning the distance from the moving contact connection end of the vacuum interrupter to the center of the guide rod hinge can also further resolve the compliance of the circuit breaker parameters.

[0049] (5) The bidirectional transmission crank arm f rotates around the fixed hinge point P. The rotation angle α of the bidirectional transmission crank arm f and the variable rod e is determined to be 30°. The center length of the lower crank arm f1 is 40mm. It rotates symmetrically α / 2, or 15°, on the vertical line below the fixed hinge point P. The left and right landing points of its rotation arc are on an approximately straight line with the center line of the fixed hinge point O and the linear guide device N. This ensures that the required closing and opening power is minimized when the circuit breaker is closing. It is beneficial for the circuit breaker to meet the contact pressure requirements when closing and the opening distance requirements when opening. It also minimizes the lateral force on the entire rod system and the friction of the rod movement. For the guide device N, the vacuum circuit breaker is either in the open position or in the closed position. The movement time of the mechanism is very short. That is, the time when the force is uniform around the guide device N is normal. In general applications, the uniform force distribution around the guide device N facilitates instantaneous activation of the mechanism during circuit breaker closing and opening, minimizes friction, and reduces the probability of transmission chain jamming. In specific applications (such as sealed guide mechanisms, which ensure that the sealing rings of the sealing mechanism are subjected to uniform force during long-term operation), the sealing is the most reliable.

[0050] (6) The mechanism output crank arm of the vacuum circuit breaker operating mechanism and the bidirectional transmission crank arm on the main transmission shaft of the circuit breaker mechanism form a planar four-bar linkage. That is, the bidirectional transmission crank arm f (f1-lower crank arm, f2-upper crank arm), the second link g, the mechanism output crank arm h, the fixed hinge point O, and the fixed hinge point P form a planar four-bar linkage. It is known that the rotation angle of the mechanism output crank arm h is 32°, the rotation angle of the bidirectional transmission crank arm f is 30°, and the hinge center length of the bidirectional transmission crank arm f is 40mm. Therefore, the hinge center length of the link is 62.7mm, and the hinge center length of the mechanism output crank arm h is 44mm. The hinge center length of the upper crank arm f2 of the bidirectional transmission crank arm f is 40mm. When closing, the angle between the second link g and the upper crank arm f2 is close to 90° (measured at 87°), ensuring that the output power of the mechanism is converted into maximum torque during closing, acting on the contacts of the vacuum circuit breaker. When opening, the angle between the second link g and the upper crank arm f2 is close to 146°. The upper crank arm f2 is the driving member. The larger the angle between the second link g and the upper crank arm f2, the faster the vacuum circuit breaker operating mechanism can open and reset, and the faster the opening speed.

[0051] The vacuum circuit breaker operating mechanism rotates its output arm by 32°, and a four-bar linkage and crank-slider-connecting rod linear mechanism are used to achieve the required contact opening distance of the vacuum interrupter. This means firstly, the contact opening distance and contact stroke are satisfied. Based on this, and considering the contact pressure requirements, the output power of the vacuum circuit breaker operating mechanism and other structural parameters are adjusted to meet the requirements for average closing speed, average opening speed, closing bounce time, asynchronous closing and opening, closing and opening time, main circuit DC resistance, and cumulative allowable wear thickness of the moving and stationary contacts. This completes the parameter design for the connection between the vacuum circuit breaker operating mechanism and the vacuum interrupter, ensuring the vacuum circuit breaker can close, carry, and interrupt current under normal circuit conditions, and can also close, carry, and interrupt current under abnormal circuit conditions (such as short circuit conditions) within a specified time.

[0052] The parameter design of the crank-slider-connecting rod linear mechanism is as follows: It enables the moving contact of the vacuum interrupter to move linearly up and down, achieving the opening distance required for reliable closing and opening of the vacuum interrupter; it enables the transverse transmission connecting rod to perform reciprocating linear motion, and the transverse transmission connecting rod is divided into a variable-length section and a constant-length section, connected by a hinge, transforming the approximately reciprocating linear motion into the reciprocating linear motion of the transverse transmission connecting rod, thus offsetting the effect of transmission rod deformation; it reduces the lateral friction of the transmission connecting rod; the contact stroke and contact pressure of the circuit breaker are designed in the variable-length section, saving design space; the transverse transmission connecting rod section and the circuit breaker... The transmission main shaft crank arm of the device mechanism is hinged, and the planar four-bar mechanism further converts the rotation angle output by the crank arm of the vacuum circuit breaker operating mechanism into the motion required by the vacuum circuit breaker. The rotation angle of the transmission crank arm is 30°. The symmetrical rotation of 15° in its vertical direction can ensure that the required closing and opening work is minimized when the circuit breaker is closing and opening. This is beneficial for the circuit breaker to meet the contact pressure requirements when closing and the opening distance requirements when opening. It also minimizes the lateral force on the movement of the entire rod system, minimizes the friction of the rod movement, and ensures that the force is uniform around the guide device in normal times, making it the most reliable guide design.

[0053] Example 2

[0054] This invention can be easily serialized to different voltage levels, current levels, and short-circuit breaking current levels. For example... Figure 7 The diagram shown is a simulated motion diagram of the closing and opening of the transmission device connecting the operating mechanism of the 24kV vacuum circuit breaker and the vacuum interrupter. Based on Example 1, by changing the length of the connecting rod a of the vacuum interrupter, the contact opening distance of the 24kV vacuum circuit breaker can be achieved to be between 12 and 14 mm, i.e., 13 ± 1 mm. The length and position of other connecting rods do not need to be changed, only the design pressure of the contact spring needs to be adjusted as needed.

[0055] Example 3

[0056] like Figure 8The diagram shows a simulated closing and opening motion of the transmission device connecting the operating mechanism of a 40.5kV vacuum circuit breaker to the vacuum interrupter. Based on Example 1, the output conditions of the vacuum circuit breaker operating mechanism remain unchanged. The rotation radius of the moving crank b and the rotating connecting rod c is changed to 47mm. The rotation center distance of the bidirectional transmission crank arm f (the upper crank arm f2 remains unchanged, and the lower crank arm f1 rotation center distance is changed to 50mm) meets the requirements of the diagram. This allows the contact opening distance of the 40.5kV vacuum circuit breaker to be between 20 and 22mm, i.e., 21±1mm. Therefore, from the perspective of motion realization, this rod motion mechanism can easily achieve serialization for different voltage levels. By appropriately changing the design pressure of the contact spring 6, serialization for different current levels and different short-circuit breaking current levels can be achieved. That is, according to the parameter design method of this invention, by changing the parameters of each rod mechanism, the design of the connection between the vacuum circuit breaker operating mechanism and the vacuum interrupter can be realized, and different design schemes can be confirmed to achieve different design objectives.

Claims

1. A method for designing parameters of a vacuum circuit breaker operating mechanism and a vacuum interrupter transmission device, characterized in that... Includes the following steps: S1. Draw a simplified diagram of the transmission device between the vacuum circuit breaker operating mechanism and the vacuum interrupter and perform motion analysis. The transmission device includes a mechanism output crank arm, a second connecting rod, a bidirectional transmission crank arm, a variable rod, a guide connecting rod, a bracket, a crank, and a rotating connecting rod. The mechanism output crank arm, the second connecting rod, and the bidirectional transmission crank arm are connected by hinges. The crank, the rotating connecting rod, and the bracket form a crank-slider-connecting rod linear mechanism. The arc of rotation of the bidirectional transmission crank arm is converted into linear motion through the sequentially connected variable rod and guide connecting rod. One end of the rotating connecting rod is hinged to the guide connecting rod, and the other end is hinged to the connecting guide rod. The crank drives the crank-slider-connecting rod linear mechanism to move. The connecting guide rod of the vacuum interrupter is fixedly connected to the moving contact of the vacuum interrupter. The bidirectional transmission crank arm rotates around the fixed hinge point two. S2. Determine the installation position of the vacuum circuit breaker operating mechanism, the center position of the rotation of the mechanism output crank arm, the starting position of the rotation of the mechanism output crank arm, and the rotation angle; wherein, the center position of the rotation of the mechanism output crank arm is fixed hinge point one. S3. Determine the installation location of the vacuum interrupter, the contact opening distance, and the position parameters of its connecting guide rod; S4. Under the above conditions, draw the design drawings: (1) Determine the length of the connecting rod of the vacuum interrupter, which is the distance from the connecting end of the moving contact of the vacuum interrupter to the center of the hinge of the connecting rod, and draw the fixed hinge point 1, the position of the connecting rod and the straight guiding device of the connecting rod on the figure. (2) Draw the position of the fixed hinge point three of the crank on the figure, and determine the rotation radius of the crank, the rotation radius of the rotating connecting rod, and the hinge center length at both ends of the rotating connecting rod of the crank-slider-connecting rod linear mechanism. (3) Preliminarily confirm the position of the main drive shaft of the circuit breaker mechanism and the length of its bidirectional drive crank arm, and determine the total length of the hinge center of the transverse drive link. Draw the position of the linear guide device on the drawing and confirm the position of the rotation center of the bidirectional drive crank arm on the main drive shaft of the mechanism. (4) The transverse transmission link consists of a variable length section and a constant length section hinged in the middle. The variable length section is a variable rod, and the constant length section is a guide link. The length of the constant length section is determined, as well as the center length of the variable length section when closing or opening the circuit breaker. The contact stroke of the circuit breaker must meet the maximum contact stroke, and the margin for further compression of the spring when closing the circuit breaker is determined. (5) Determine the rotation angle α of the bidirectional transmission crank arm around the transmission main shaft of the circuit breaker mechanism, and rotate α / 2 symmetrically to the left and right of the vertical line passing through the center of rotation; (6) The output crank arm of the vacuum circuit breaker operating mechanism and the bidirectional transmission crank arm on the main transmission shaft of the circuit breaker mechanism form a planar four-bar linkage through the second link. Given the rotation angle of the output crank arm, the rotation angle of the bidirectional transmission crank arm, and the hinge center length of the bidirectional transmission crank arm, the hinge center length of the second link and the hinge center length of the output crank arm are obtained, thus completing the parameter design of the transmission device. When the contact opening distance, contact stroke, and contact contact pressure of the circuit breaker cannot meet the design requirements, the contact opening distance is first changed by altering the length of the connecting rod of the vacuum interrupter. At the same time, the contact stroke, contact contact pressure, and contact pressure will also change accordingly. The magnitude of the data change is related to the size of the contact opening distance, and the data must be within the design tolerance range.

2. The parameter design method for the vacuum circuit breaker operating mechanism and vacuum interrupter transmission device according to claim 1, characterized in that: In step S4(4), the theoretical design considers that the contact stroke is ≥4mm to meet the maximum contact stroke, and also considers the margin for further compression of the spring when the switch is closed. The theoretical design margin is 1-2mm.

3. The parameter design method for the vacuum circuit breaker operating mechanism and vacuum interrupter transmission device according to claim 1, characterized in that: In step S4(4), the conformity of the specific parameters is confirmed during prototype debugging by fine-tuning the contact gap and contact stroke.

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