Power supply switching device for frequency converter of coal feeder of thermal power plant

Abstract

The utility model relates to the technical field of frequency converter power supply switching, and discloses a thermal power plant coal feeder frequency converter power supply switching device, which comprises a fixed block and a frequency converter fixedly arranged at the upper end of the fixed block, when the device is normally used, power is supplied by a power supply main line, an electromagnet is in a power-on state, and electromagnetic force is generated to adsorb a movable block; when the power supply main line breaks down, the electromagnet is powered off, the attraction force of the electromagnet to the movable block disappears at the moment, the movable block is automatically pulled to the other side along the movable cavity under the action of the spring, and when the movable block moves to the maximum movable distance, the standby power supply line outputs current to the movable block at the moment; the power supply switching device of the frequency converter of the coal feeder of the thermal power plant uses the electromagnet to enable the conductive movable block to be located between the power supply main line and the output line in an initial state, the circuit is switched on, the magnetic force of the electromagnet disappears when the power supply main line breaks down and is short-circuited, and the standby power supply line is automatically switched on under the action of the spring; and a standby line can be quickly switched.

Description

Technical Field

[0001] This utility model relates to the field of frequency converter power switching technology, specifically a power switching device for a frequency converter of a coal feeder in a thermal power plant. Background Technology

[0002] Currently, low-voltage ride-through devices have been installed to address the low-voltage ride-through phenomenon in coal feeder frequency converters. However, this does not completely solve the problem. From the working principle of the frequency converter, for it to operate normally under voltage fluctuations, both the power circuit and the control circuit must have reliable power supply. The current solution for low-voltage ride-through in coal feeder frequency converters involves two main aspects: the power circuit primarily provides a stable DC power supply to the frequency converter's DC bus to ensure voltage stability during inversion; the control circuit primarily uses either a 1KVA small UPS or a large on-site UPS. However, based on current upgrades in most domestic thermal power plants, the 1KVA small UPS has a high failure rate, and its maintenance is easily overlooked, especially regarding battery charging and discharging. Furthermore, its lifespan is short, typically requiring battery replacement every two years, resulting in significant maintenance workload. Using a large on-site UPS is relatively more reliable, but several boiler fires in recent years have occurred due to UPS failures, primarily caused by quality issues with the UPS itself.

[0003] When the power supply line of the frequency converter ages and fails after long-term use, the power supply will be directly disconnected, interrupting the normal operation of the device. Depending on the maintenance time of the staff, it will also affect the normal work efficiency. In order to protect the electrical device, the power supply line will actively disconnect the circuit when a fault occurs. This can only protect the device but affects the operation, which has certain shortcomings in actual use.

[0004] Therefore, we propose a power switching device for the frequency converter of a coal feeder in a thermal power plant to solve the problems mentioned above. Utility Model Content

[0005] The purpose of this utility model is to provide a power switching device for the frequency converter of a coal feeder in a thermal power plant, in order to solve the problem mentioned in the background art where, when the power supply line of the frequency converter ages and fails after long-term use, the power supply will be directly disconnected, the power supply will be interrupted, and the normal operation of the device will be affected. Depending on the maintenance time of the staff, it will also affect the normal work efficiency. In order to protect the electrical equipment, the power supply line will actively cut off the circuit when a fault occurs. This can only protect the device but affects the operation, which has certain shortcomings in actual use.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a power switching device for a frequency converter of a coal feeder in a thermal power plant, comprising a fixed block and a frequency converter fixedly installed on the upper end of the fixed block. A main power supply line and a backup power supply line are fixedly installed on one side wall of the fixed block, and an output circuit is fixedly installed on the other side of the fixed block. A movable chamber is formed inside the fixed block, and a movable block is slidably connected inside the movable chamber. Moving contacts are fixedly installed on both side walls of the movable block. A metal plate is fixedly installed between the fixed block and the output circuit, and the moving contacts are slidably connected to the metal plate. An electromagnet is fixedly installed on one inner wall of the movable chamber, and the electromagnet is electrically connected to the main power supply line. A spring is fixedly installed between one side of the movable block and the inner wall of the movable chamber.

[0007] Preferably, the movable block is a metal block, and the movable block is electrically connected to the frequency converter.

[0008] Preferably, the two side walls of the movable chamber are respectively provided with a sliding groove one and a sliding groove two, and the two moving contacts are slidably connected in the two sliding grooves two respectively.

[0009] Preferably, the main power supply line and the backup power supply line are respectively located at both ends of the slide groove.

[0010] Preferably, a limiting block is fixedly installed on one inner wall of the movable chamber, and the limiting block is disposed inside the spring.

[0011] Preferably, the lower side wall of the fixed block is provided with a sliding groove three, and a manual adjustment rod is slidably connected in the sliding groove three. One end of the manual adjustment rod is fixedly connected to the side wall of the movable block.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. Under normal use, the device is powered by the main power supply line, and the electromagnet is energized, generating electromagnetic force to attract the movable block. When the main power supply line fails, the electromagnet disconnects the power supply, and the attraction of the electromagnet to the movable block disappears. Under the action of the spring, the movable block is automatically pulled to the other side along the movable chamber. When it moves to the maximum movable distance, the backup power supply line outputs current to the movable block. In the initial state, the power switching device of the coal feeder frequency converter in the thermal power plant uses the electromagnet to keep the conductive movable block between the main power supply line and the output line, and connects the circuit. When the main power supply line fails and short-circuits, the magnetic force of the electromagnet disappears, and the backup power supply line is automatically connected under the action of the spring, which can quickly switch to the backup line.

[0014] 2. With the cooperation of slide rail three, slide rail one, slide rail two, moving contact, limit block and manual adjustment rod, the device can intuitively judge the line status of the main power supply line by the position of the manual adjustment rod when in use. When a fault is repaired and the movable block is brought back to the main power supply line by manually adjusting the rod, the electromagnet can automatically attract and fix the movable block. The operation is simple. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall three-dimensional structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the overall longitudinal cross-sectional three-dimensional structure of this utility model;

[0017] Figure 3 This is a schematic diagram of the overall transverse cross-sectional three-dimensional structure of this utility model;

[0018] Figure 4 For the present utility model Figure 3 Enlarged 3D structural diagram at point A.

[0019] In the diagram: 1. Fixed block; 11. Movable chamber; 12. Movable block; 13. Spring; 14. Slide three; 15. Slide one; 16. Slide two; 17. Moving contact; 2. Frequency converter; 3. Backup power supply line; 4. Main power supply line; 5. Output circuit; 51. Metal plate; 6. Electromagnet; 7. Limit block; 8. Manual adjustment rod. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Example 1: Please refer to Figure 1 - Figure 3A power switching device for a frequency converter of a coal feeder in a thermal power plant includes a fixed block 1 and a frequency converter 2 fixedly installed on the upper end of the fixed block 1. A main power supply line 4 and a backup power supply line 3 are fixedly installed on one side wall of the fixed block 1, and an output circuit 5 is fixedly installed on the other side of the fixed block 1. A movable chamber 11 is opened inside the fixed block 1, and a movable block 12 is slidably connected inside the movable chamber 11. Moving contacts 17 are fixedly installed on both side walls of the movable block 12. A metal plate 51 is fixedly installed between the fixed block 1 and the output circuit 5. The moving contacts 17 are slidably connected to the metal plate 51. An electromagnet 6 is fixedly installed on one inner wall of the movable chamber 11. The electromagnet 6 is electrically connected to the main power supply line 4. A spring 13 is fixedly installed between one side of the movable block 12 and the inner wall of the movable chamber 11.

[0022] In this embodiment: When the device is in normal use, the current flows outward through the main power supply line 4 to the movable block 12 and then to the output line 5. The frequency converter 2 is used to control the output current. At this time, since the main power supply line 4 is powered, the electromagnet 6 is energized and generates electromagnetic force to attract the movable block 12 to the side close to the electromagnet 6. When the main power supply line 4 fails, the electromagnet 6 disconnects the power supply. At this time, the attraction of the electromagnet 6 to the movable block 12 disappears. Under the action of the spring 13, the movable block 12 is automatically pulled to the other side along the movable chamber 11. When it moves to the maximum movable distance, the backup power supply line 3 outputs current to the movable block 12. In the initial state, the power switching device of the coal feeder frequency converter in the thermal power plant uses the electromagnet 6 to make the conductive movable block 12 located between the main power supply line 4 and the output line 5 and connect the circuit. When the main power supply line 4 fails and short-circuits, the magnetic force of the electromagnet 6 disappears. Under the action of the spring 13, the backup power supply line 3 is automatically connected, and the device can quickly switch to the backup line.

[0023] Example 2: This example is an improvement on Example 1. For details, please refer to [link / reference]. Figure 2 - Figure 4 The movable block 12 is a metal block, and the movable block 12 is electrically connected to the frequency converter 2. The metal movable block 12 can be attracted by the electromagnet 6 when it is energized.

[0024] The two side walls of the movable chamber 11 are respectively provided with a sliding groove 15 and a sliding groove 16. Two moving contacts 17 are slidably connected in the two sliding grooves 16. The sliding grooves 15 and 16 can limit the moving contacts 17 on both sides.

[0025] The main power supply line 4 and the backup power supply line 3 are respectively set at both ends of the slide groove 15. When the moving contact 17 moves to both ends, power is supplied through the main power supply line 4 and the backup power supply line 3 respectively.

[0026] A limiting block 7 is fixedly installed on one inner wall of the movable chamber 11. The limiting block 7 is located inside the spring 13. The limiting block 7 further limits the movable block 12 and restricts its movement distance.

[0027] The lower side wall of the fixed block 1 is provided with a sliding groove 3 14. A manual adjustment rod 8 is slidably connected in the sliding groove 3 14. One end of the manual adjustment rod 8 is fixedly connected to the side wall of the movable block 12. When the movable block 12 moves, it can drive the manual adjustment rod 8 to slide along the sliding groove 3 14. Similarly, the position of the movable block 12 can be adjusted by the manual adjustment rod 8.

[0028] In this embodiment: when the main power supply line 4 is normal, the movable block 12 is located as follows: Figure 2 , Figure 3 At the position shown, the electromagnet 6 is energized and attracts the movable block 12. When the main power supply line 4 is disconnected, the magnetic force of the electromagnet 6 also disappears. Under the tension of the spring 13, the movable block 12 slides along the inner wall of the movable chamber 11. During the sliding process, the movable block 12 drives the moving contacts 17 on both sides to slide along the first slide groove 15 and the second slide groove 16, and drives the manual adjustment rod 8 at the lower end to slide along the third slide groove 14 to the other side. When the movable block 12 slides to the other side of the first slide groove 15 and the second slide groove 16, the moving contact 17 in the first slide groove 15 is connected to the backup power supply line 3, and the device is powered through the backup power supply line 3. The position of the manual adjustment rod 8 has changed, allowing for a direct visual assessment of whether the main power supply line 4 is functioning normally during maintenance. After maintenance of the main power supply line 4, the manual adjustment rod 8 can be manually slid along the slide groove 14 to the other end. Under the attraction of the electromagnet 6, the movable block 12 can be limited. When using this device, the position of the manual adjustment rod 8 can be used to visually determine the condition of the main power supply line 4. After a fault is repaired, the movable block 12 can be brought back to the position of the main power supply line 4 using the manual adjustment rod 8. The electromagnet 6 can automatically attract and fix the movable block 12. The operation is simple.

[0029] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0030] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power switching device for a frequency converter of a coal feeder in a thermal power plant, comprising a fixed block (1) and a frequency converter (2) fixedly installed on the upper end of the fixed block (1), wherein a main power supply line (4) and a backup power supply line (3) are fixedly installed on one side wall of the fixed block (1), and an output circuit (5) is fixedly installed on the other side of the fixed block (1), characterized in that: The fixed block (1) has an open movable chamber (11) inside. A movable block (12) is slidably connected inside the movable chamber (11). Movable contacts (17) are fixedly installed on both sides of the movable block (12). A metal plate (51) is fixedly installed between the fixed block (1) and the output circuit (5). The movable contacts (17) are slidably connected to the metal plate (51). An electromagnet (6) is fixedly installed on one side of the inner wall of the movable chamber (11). The electromagnet (6) is electrically connected to the main power supply line (4). A spring (13) is fixedly installed between one side of the movable block (12) and the inner wall of the movable chamber (11).

2. The power switching device for a frequency converter of a coal feeder in a thermal power plant according to claim 1, characterized in that: The movable block (12) is a metal block, and the movable block (12) is electrically connected to the frequency converter (2).

3. The power switching device for a frequency converter of a coal feeder in a thermal power plant according to claim 2, characterized in that: The two side walls of the movable chamber (11) are respectively provided with a sliding groove one (15) and a sliding groove two (16), and the two moving contacts (17) are respectively slidably connected in the two sliding grooves two (16).

4. A power switching device for a frequency converter of a coal feeder in a thermal power plant according to claim 3, characterized in that: The main power supply line (4) and the backup power supply line (3) are respectively located at both ends of the slide groove (15).

5. A power switching device for a frequency converter of a coal feeder in a thermal power plant according to claim 4, characterized in that: A limiting block (7) is fixedly installed on one inner wall of the active chamber (11), and the limiting block (7) is located inside the spring (13).

6. A power switching device for a frequency converter of a coal feeder in a thermal power plant according to claim 5, characterized in that: The lower side wall of the fixed block (1) is provided with a sliding groove three (14), and a manual adjustment rod (8) is slidably connected in the sliding groove three (14). One end of the manual adjustment rod (8) is fixedly connected to the side wall of the movable block (12).

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