Single-phase switching mechanism and split-type on-load tap-changer

Abstract

The invention discloses a single-phase switching mechanism and a split type on-load tap-changer, and belongs to the technical field of on-load tap-changers. The device comprises a trigger device, execution mechanisms and a measurement protection device, the execution mechanisms are symmetrically arranged at the top of the trigger device, the trigger device is used for driving the execution mechanisms, and the measurement protection device is connected with the execution mechanisms and used for protecting the execution mechanisms; the executing mechanism comprises a plurality of permanent magnet quick switches, and the plurality of permanent magnet quick switches form two groups of two-series two-parallel switch structures through series-parallel copper bars; the measurement protection device comprises lightning arresters and an electronic current transformer, the lightning arresters are arranged at the two ends of an inlet wire of the single-phase switching mechanism, and the electronic current transformer is connected with an outlet wire of the execution mechanism in a penetrating mode and used for monitoring the circulating current value; the state of the switching mechanism is monitored online in real time, and effective state monitoring of the switching mechanism is improved.

Description

Technical Field

[0001] The invention relates to a single-phase switching mechanism and a split-type on-load tap changer, belonging to the technical field of on-load tap changers. Background Art

[0002] In power systems, on-load tap-changers (OLTs) are key devices for dynamically adjusting transformer ratios without power outages. Their reliable and stable operation directly impacts the safe operation of the power grid. Currently, the OLTs used in large-capacity transformers with voltage levels of 110kV and above in China are primarily classified by arc extinguishing medium as either oil-based or vacuum-based. These OLTs are installed within the transformer's oil compartment. A failure during the arc extinguishing process can easily cause the OLT to catch fire or explode, damaging the transformer and potentially affecting the entire converter transformer or other substation equipment, severely harming the power grid.

[0003] In order to avoid the impact of on-load tap-changer failure on transformers and substations, solve the problems of existing traditional on-load tap-changers, such as failure of operation caused by wear of the switching mechanism, fire caused by carbonization of transformer oil insulation, and lack of reliable intelligent monitoring means to monitor the status in real time. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a single-phase switching mechanism and a split-type on-load tap changer. The on-load tap changer switching mechanism is separated from the transformer oil compartment and installed indoors or in a container. This allows the switching mechanism to operate without oil, and the switching mechanism status is monitored in real time to ensure the reliability of the on-load tap changer. In order to achieve the above objectives / solve the above technical problems, the present invention is implemented by adopting the following technical solutions: A first aspect: A single-phase switching mechanism includes a trigger device, an actuator, and a measurement and protection device, wherein the actuator is symmetrically arranged on top of the trigger device, the trigger device is used to drive the actuator, and the measurement and protection device is connected to the actuator to protect the actuator; The actuator includes a plurality of permanent magnetic fast switches, which are connected in series and parallel with copper bars to form two groups of two-series and two-parallel switch structures; The measuring and protecting device includes a lightning arrester and an electronic current transformer. The lightning arrester is arranged at both ends of the single-phase switching mechanism incoming line. The electronic current transformer is connected to the actuator outgoing line for monitoring the circulating current value.

[0005] Optionally, the permanent magnet fast switch includes a switch frame, an operating mechanism, an insulating pull rod, a vacuum interrupter, an opening and closing monitoring device, and a permanent magnet fast switch inlet line. The switch frame is arranged on the top of the trigger device, one end of the insulating pull rod is connected to the operating mechanism, and the other end is threadedly connected to the vacuum interrupter. The laser emitted from the background of the opening and closing monitoring device passes through the baffle of the insulating pull rod to determine the opening and closing status of the permanent magnet fast switch; One end of the permanent magnet fast switch incoming line is connected to the vacuum interrupter, and the other end is connected to the series-parallel copper busbar.

[0006] Optionally, the trigger device includes a bottom support insulator and an energy supply device. The lower end of the bottom support insulator is fixedly mounted on the ground, and the upper end is provided with a placement box. The placement box is provided with a control chassis, an energy storage capacitor and a power supply module. The power supply module is used to provide power for the energy storage capacitor. The control chassis is used to control the discharge of the energy storage capacitor, so that the operating mechanism generates a force opposite to the permanent magnet, and controls the opening and closing of the permanent magnet fast switch. The energy supply device provides power to the entire mechanism through a cable.

[0007] Optionally, the placement box includes an upper mounting plate and a lower mounting plate, and the upper mounting plate and the lower mounting plate are connected by an intermediate support to form a frame, and door panels are provided on both end faces of the frame, and heat dissipation decorative panels are provided on both side faces.

[0008] Optionally, the door panel is provided with a mounting hole for mounting a control chassis, the door panel is rotatably connected to the frame, and the control chassis can rotate along with the door panel.

[0009] Optionally, the energy storage capacitors are mounted on the lower mounting plate, arranged in a row with the front and back facing each other.

[0010] Optionally, the middle support is arranged with several groups of wiring troughs and power module mounting plates, and the bottom of the lower mounting plate is symmetrically installed with optical cable troughs.

[0011] Optionally, the heat dissipation panel is provided with heat dissipation holes.

[0012] Optionally, the electronic current transformer includes a sensor head and a remote module, the internal coil of the sensor head is a Rogowski coil, and the remote module is used to convert and transmit the measured current value.

[0013] A second aspect: A split on-load tap changer, comprising the single-phase switching mechanism described in the first aspect.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention is equipped with a trigger device, an actuator, and a measurement and protection device. Compared with the prior art, the switching mechanism is decoupled from the transformer, solving the problem of damage to the transformer and substation caused by a failure of the on-load tap changer switching mechanism. The trigger device is integrated into a cabinet structure, which has a compact overall layout and improves maintainability. The actuator of the present invention includes a permanent magnet fast switch, which is connected in series and parallel through copper bars to perform opening and closing actions in a time sequence, ensuring continuous and reliable operation; The measuring and protection device of the present invention is used for real-time online monitoring of the state of the switching mechanism, thereby improving effective state monitoring of the switching mechanism. In addition, the single-phase switching mechanism of the present invention can be arranged in a single-phase or three-phase common box configuration, thereby improving the selectivity of on-site configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a schematic diagram of the overall structure of the single-phase switching mechanism of the present invention; Figure 2 Shown is a schematic diagram of the internal structure of the single-phase switching mechanism of the present invention; Figure 3 Shown is a side view of the single-phase switching mechanism of the present invention; Figure 4 Shown is a front view of the single-phase switching mechanism of the present invention; Figure 5 Shown is a schematic diagram of an electronic current transformer of a single-phase switching mechanism of the present invention; Figure 6 Shown is a schematic diagram of a permanent magnet fast switch of a single-phase switching mechanism of the present invention; Figure 7 The figure shows the distribution diagram of the permanent magnet fast switch of the present invention; Figure 8 The figure shows a schematic diagram of the structure of the permanent magnet fast switching circuit of the present invention; In the figure: 1-trigger device, 2-actuator, 3-measurement and protection device, 4-optical cable trough; 5-actuator outlet; 10-heat dissipation panel, 11-bottom support insulator, 12-energy supply device, 13-control chassis, 14-door panel, 15-energy storage capacitor, 16-power module, 17-upper mounting plate, 18-middle workplace, 19-lower mounting plate; 21-permanent magnet fast-acting switch, 22-series-parallel copper busbar; 26-actuator incoming line; 211-switch frame, 212-operating mechanism, 213-insulating pull rod, 214-vacuum interrupter, 215-opening and closing monitoring device; 216-permanent magnet fast-acting switch incoming line; 31-lightning arrester, 32-electronic current transformer, 321-sensor head, 322-remote module. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0018] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances. Example

[0019] like Figures 1-6 As shown, a single-phase switching mechanism is disclosed, including a trigger device 1, an actuator 2, and a measurement and protection device 3. The trigger device 1 forms a cabinet frame structure as a whole. The actuator 2 is symmetrically arranged on the top of the trigger device 1 and connected by a series-parallel copper busbar auxiliary 22. The trigger device 1 is used to drive the actuator 2, and the measurement and protection device 3 is connected to the actuator 2 to protect the actuator 2. The actuator 2 includes a plurality of permanent magnetic fast switches 21, which are connected in series and parallel with copper bars 22 to form two groups of two-series and two-parallel switch structures. The measurement and protection device 3 includes a lightning arrester 31 and an electronic current transformer 32. The lightning arrester 31 is installed at both ends of the single-phase switching mechanism incoming line 26. The lightning arrester 31 is supported and mounted on the upper mounting plate 17 by insulators, which provide isolation. The electronic current transformer 32 is connected to the actuator outgoing line 5 and is used to monitor the circulating current value and measure the current value flowing through the permanent magnetic fast-acting switch 21. The permanent magnetic fast-acting switch 21 is controlled and protected based on the measured value. The electronic current transformer 32 is mounted on the upper mounting plate 17 via channel steel and has the same electrical potential as the upper mounting plate 17.

[0020] In the specific implementation process of this embodiment, Figure 6 As shown, the permanent magnetic fast switch 21 includes a switch frame 211, an operating mechanism 212, an insulating pull rod 213, a vacuum interrupter 214, an opening and closing monitoring device 215, and a permanent magnetic fast switch inlet line 216. The switch frame 211 is arranged on the top of the trigger device 1. One end of the insulating pull rod 213 is connected to the operating mechanism 212, and the other end is threadedly connected to the vacuum interrupter 214. The opening and closing monitoring device 215 is used to monitor the opening and closing status of the vacuum interrupter 214. The opening and closing status of the permanent magnetic fast switch 21 is determined by the laser emitted from the background through the baffle of the insulating pull rod 213. One end of the permanent magnet fast switch incoming line 216 is connected to the vacuum interrupter 214 to provide an incoming line interface, and the other end is connected to the series-parallel copper bus 22; Furthermore, in the initial state, the vacuum interrupter 214 is in a closed state, and the opening and closing monitoring device 215 can monitor the opening and closing states of the vacuum interrupter.

[0021] like Figure 1 As shown, the trigger device 1 includes a bottom support insulator 11 and an energy supply device 12. The lower end of the bottom support insulator 11 is fixedly installed on the ground, and the upper end is provided with a placement box. The placement box is provided with a control chassis 13, an energy storage capacitor 15 and a power module 16. The power module 16 is used to provide power for the energy storage capacitor 15. The control chassis 13 is used to control the discharge of the energy storage capacitor 15, so that the operating mechanism 212 generates a force opposite to the permanent magnet, and controls the opening and closing of the permanent magnet fast switch 21. The energy supply device 12 provides power to the entire mechanism through a cable.

[0022] In the specific implementation of this embodiment, the storage box includes an upper mounting plate 17 and a lower mounting plate 19, which are connected by an intermediate support 18 to form a frame. The frame is provided with door panels 14 at both ends and heat dissipation panels 10 on both sides. The door panels 14 are provided with mounting holes for mounting the control chassis 13. The door panels 14 are rotatably connected to the frame, and the control chassis 13 can rotate with the door panels 14. It is worth noting that the door panels 14 and the frame achieve rotational function via hinges or pins.

[0023] like Figure 2 As shown, the energy storage capacitor 15 is mounted on the lower mounting plate 19 , with the front and back sides arranged in a row.

[0024] The middle support 18 is provided with several groups of wiring troughs and power module mounting plates, and the bottom of the lower mounting plate is symmetrically provided with optical cable troughs 4 to facilitate the neatness of wiring.

[0025] The heat dissipation decorative plate 10 is provided with heat dissipation holes to facilitate daily heat dissipation of the heating components.

[0026] like Figure 3 and Figure 5 As shown, the electronic current transformer 32 includes a sensor head 321 and a remote module 322. The internal coil of the sensor head 321 is a Rogowski coil, which avoids the problem of magnetic flux saturation and improves measurement accuracy. The remote module is also configured for conversion and transmission of measurement values.

[0027] like Figure 7-Figure 8 As shown, the two groups of two-string and two-parallel permanent magnet fast switches 21 formed by the actuator 2 are K11, K12, K13, K14, K21, K22, K23, and K24, totaling 8 permanent magnet fast switches 21, forming 4 branches, including two main current branches and two transition branches. Each transition branch is connected in series with transition resistors R1 and R2. Electronic current transformers 32 are arranged in all four branches to monitor the current of each branch. The switching method of the single-phase switching mechanism includes the following specific time-sharing and step-by-step actions: (1) Initial state: A group of switch mechanisms consisting of K11, K12, K13, and K14 are all in the closed position, and the current flows through the main flow branches of K11 and K12; (2) Action 1: The switches K11 and K12 of the main flow branch 1 are opened, and all the current is transferred to the transition branch 1 of K13 and K14. If the opening and closing monitoring device 215 determines that the switches K11 and K12 are in the open position and the current of the main flow branch of K11 and K12 is 0, the next step is executed. If the judgment criterion is not met, the switches K11 and K12 are reclosed and the state is restored to the initial state.

[0028] (3) Action 2: The switch K14 connected in parallel with the transition resistor R1 in the transition branch 1 is opened, and the transition resistor R1 is put into operation. If the opening and closing monitoring device 215 determines that the switch K14 is in the open position and the switch current of K14 is 0, the next step is executed. If the judgment criterion is not met, the reclosing switches K11, K12, and K14 are restored to the initial state; (4) Action 3: The switch K23 in the transition branch 2 is closed. At this time, the K13, K23, R1, and R2 of the two transition branches form a loop, generating a circulating current. If the opening and closing monitoring device 215 determines that the switch K23 is closed and the generated circulating current is not zero, the next step is executed. If the judgment criterion is not met, K22 is opened first, and then the switches K11, K12, and K14 are reclosed to restore them to the initial state; (5) Action 4: The switch K13 in the transition branch 1 is opened, and the circulating current disappears. If the opening monitoring device 215 determines that the switch K13 is opened, and the current of the transition resistor R1 in the transition branch 1 is 0, the next step is executed. If the judgment criterion is not met, the switches K11, K12, K13, and K14 are reclosed, and the switch K23 is restored to the initial state; (6) Action 5: The switch K24 in the transition branch 2 is closed, and the transition resistor R2 is removed. If the opening and closing monitoring device 215 determines that the switch K24 is closed and the current of the transition resistor in the transition branch 2 is 0, the next step is executed. If the judgment criterion is not met, the switches K21 and K22 are closed, and the current flows through the main flow branch 2; (7) Action 6: The switches K21 and K22 of the main flow branch 2 are closed, and the switching action is completed.

[0029] Throughout the switching process, the position of the permanent magnetic fast-acting switch 21 is monitored in real time by the opening and closing monitoring device 215, and the current in each branch is monitored in real time by the electronic current transformer 32. The position of the permanent magnetic fast-acting switch and the current in each branch are factored into the logical judgment of the switching action. In the event of an anomaly, the fault handling logic is executed to ensure that internal short-circuit faults within the switch are avoided. Furthermore, a lightning arrester 31 is installed in parallel at the input of the entire switching mechanism to limit overvoltage at the switching mechanism input and ensure that the switching mechanism operates within a safe voltage range.

[0030] In the single-phase switching mechanism, the actuators form two groups of two-series, two-parallel switch structures, forming two main flow branches and transition branches, respectively. During normal operation, one group of main flow branches and transition branch switches are closed. When a switching action is required, the main flow branch switch mechanism opens, transferring the current to the transition branch. The second group of transition branch switch mechanisms switches from open to closed in a time-sharing manner. The second group of main flow branch switch mechanisms also switches from open to closed. The first group of transition branch switch mechanisms opens, transferring the current from the transition branch to the main flow branch of the second group of switch mechanisms, completing the step-by-step time-sharing switching action. Simultaneously, the measurement and protection device monitors current and voltage in real time to ensure that the single-phase switching mechanism operates within the normal range.

[0031] Example 2: A split on-load tap changer, comprising the single-phase switching mechanism described in Example 1.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A single-phase switching mechanism, characterized in that: The invention comprises a trigger device (1), an actuator (2) and a measuring and protecting device (3), wherein the actuator (2) is symmetrically arranged on the top of the trigger device (1), the trigger device (1) is used to drive the actuator (2), and the measuring and protecting device (3) is connected to the actuator (2) and is used to protect the actuator (2); The actuator (2) comprises a plurality of permanent magnetic fast switches (21), wherein the plurality of permanent magnetic fast switches (21) are connected in series and parallel via copper bars (22) to form two groups of two-series and two-parallel switch structures; The measuring and protecting device (3) comprises a lightning arrester (31) and an electronic current transformer (32). The lightning arrester (31) is provided at both ends of the single-phase switching mechanism incoming line (26). The electronic current transformer (32) is connected to the actuator outgoing line (5) and is used to monitor the circulating current value.

2. The single-phase switching mechanism according to claim 1, characterized in that: The permanent magnetic fast switch (21) comprises a switch frame (211), an operating mechanism (212), an insulating pull rod (213), a vacuum interrupter (214), an opening and closing monitoring device (215), and a permanent magnetic fast switch inlet line (216); the switch frame (211) is arranged on the top of the trigger device (1); one end of the insulating pull rod (213) is connected to the operating mechanism (212), and the other end is threadedly connected to the vacuum interrupter (214); a laser emitted from the back of the opening and closing monitoring device (215) passes through a baffle of the insulating pull rod (213) to judge the opening and closing state of the permanent magnetic fast switch (21); One end of the permanent magnet fast switch incoming line (216) is connected to the vacuum interrupter (214), and the other end is connected to the series-parallel copper busbar (22).

3. The single-phase switching mechanism according to claim 2, characterized in that: The trigger device (1) includes a bottom support insulator (11) and an energy supply device (12). The bottom support insulator (11) is fixedly mounted on the ground at its lower end and provided with a placement box at its upper end. The placement box is provided with a control chassis (13), an energy storage capacitor (15) and a power module (16). The power module (16) is used to provide power to the energy storage capacitor (15). The control chassis (13) is used to control the discharge of the energy storage capacitor (15) so that the operating mechanism (212) generates a force opposite to the permanent magnet, thereby controlling the opening and closing of the permanent magnet fast switch (21). The energy supply device (12) provides power to the entire mechanism through a cable.

4. The single-phase switching mechanism according to claim 3, characterized in that: The placement box comprises an upper mounting plate (17) and a lower mounting plate (19), wherein the upper mounting plate (17) and the lower mounting plate (19) are connected via an intermediate support (18) to form a frame, and door panels (14) are provided at both end surfaces of the frame, and heat dissipation decorative panels (10) are provided on both side surfaces.

5. The single-phase switching mechanism according to claim 4, characterized in that: The door panel (14) is provided with a mounting hole for mounting the control chassis (13); the door panel (14) is rotatably connected to the frame; and the control chassis (13) can rotate along with the door panel (14).

6. The single-phase switching mechanism according to claim 4, characterized in that: The energy storage capacitors (15) are mounted on the lower mounting plate (19) and arranged in a row with the front and back facing each other.

7. The single-phase switching mechanism according to claim 4, characterized in that: The middle support (18) is provided with a plurality of wiring troughs and a power module mounting plate, and the bottom of the lower mounting plate is symmetrically provided with an optical cable trough (4).

8. The single-phase switching mechanism according to claim 4, characterized in that: The heat dissipation decorative plate (10) is provided with heat dissipation holes.

9. The single-phase switching mechanism according to claim 1, characterized in that: The electronic current transformer (32) comprises a sensor head (321) and a remote module (322). The internal coil of the sensor head (321) is a Rogowski coil, and the remote module (322) is used to convert and transmit the measured current value.

10. A split-type on-load tap-changer, characterized in that: It includes the single-phase switching mechanism described in any one of claims 1-9.

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