Three-position disconnecting switch and contact pressure monitoring device

Abstract

The invention relates to a contact pressure monitoring device for a three-position disconnecting switch and a contact, and belongs to the field of primary power equipment. A contact contact pressure monitoring device is additionally arranged on the basis of an original three-station isolating switch, pressure is generated on the spring when the isolating switch rotates, shear stress is generated on the stress sensor by the pressure of the spring, and the strain resistance value of the stress sensor is changed by the shear stress, so that the contact pressure of the isolating switch contact is detected. According to the invention, the online monitoring function of the contact pressure of the disconnecting switch contact is realized, and technical support is provided for intelligent upgrading of the gas-insulated switchgear.

Description

Technical Field

[0001] The invention relates to a three-position isolating switch and a contact pressure monitoring device, belonging to the field of electric power primary equipment. Background Art

[0002] As the most important and critical equipment in the power system, the reliability of switchgear directly affects the reliability of power supply. The isolating switch is a switchgear that carries current and provides a clear maintenance port. Whether the isolating switch can stably and reliably carry the rated current of the normal circuit and the rated short-circuit current is directly related to the stability of the power system.

[0003] The stability and reliability of disconnect switches are closely linked to the cross-sectional dimensions of the disconnecting switch conductors and the contact pressure of the disconnecting switch contacts. Traditional inflatable cabinet disconnect switches rely on contact springs to maintain contact pressure. When the springs fail due to fatigue, the contact pressure drops, reducing the current-carrying capacity of the disconnect switch. Because all conductors in the high-voltage circuits of the inflatable cabinets are fully sealed and shielded, measuring the circuit resistance is difficult, making it impossible to detect contact pressure. This makes it difficult to detect abnormal contact pressure on disconnecting switches during routine inspections. Summary of the Invention

[0004] The purpose of the present invention is to provide a three-position isolating switch and a contact pressure monitoring device to solve the problem that it is difficult to detect whether the contact pressure of the isolating switch is abnormal during the current inspection process.

[0005] In order to solve the above technical problems, the present invention provides a three-position isolating switch, including an isolating knife switch 1, an insulating pull rod 6, and a contact pressure spring 18. The insulating pull rod 6 drives the isolating knife switch 1 to realize the three positions of opening, closing, and grounding of the isolating knife switch 1. It also includes a stress sensor that can sense the pressure of the contact pressure spring 18 when the isolating knife switch 1 rotates to generate pressure on the contact pressure spring 18.

[0006] The present invention uses a stress sensor to detect the shear stress generated by the pressure of the spring on the stress sensor when the isolating knife switch rotates and generates pressure on the spring, thereby realizing the online monitoring function of the contact pressure of the isolating switch contacts and providing technical support for the intelligent upgrade of the inflatable cabinet.

[0007] Furthermore, the stress sensor is an axle pin sensor, the axle pin sensor 16 passes through the sensor sleeve 15 horizontally, and the end face of the contact pressure spring 18 presses on the washer 17, transferring the pressure to the washer 17. The washer 17 presses the sensor sleeve 15, so that the sensor sleeve 15 applies a radial shear stress to the axle pin sensor 16.

[0008] Furthermore, the three-position isolating switch further includes a wireless signal transmitter 14 connected to the stress sensor, for converting the electrical signal detected by the stress sensor into a wireless digital signal.

[0009] The use of wireless digital signals solves the problem of high-voltage insulation of sensors.

[0010] Furthermore, the isolation knife switch 1 is arranged in a sealed housing, and a sealing plug 7 is provided on the housing for the wireless line signal emitted by the wireless signal transmitter 14 to penetrate.

[0011] Since the signal transmitter is sealed in a stainless steel air chamber, the wireless digital signal cannot be transmitted out of the sealed metal shell. By providing a sealing plug cover on the shell, the wireless digital signal can be transmitted out of the shell.

[0012] The present invention also provides a contact pressure monitoring device, including a stress sensor and a wireless signal transmitter 14. The stress sensor is used to sense the pressure generated on the contact pressure spring when the isolation switch rotates. The wireless signal transmitter is communicatively connected to the stress sensor and is used to convert the electrical signal detected by the stress sensor into a wireless digital signal.

[0013] The present invention uses a stress sensor to detect the shear stress generated by the pressure of the spring on the stress sensor when the isolating knife switch rotates and generates pressure on the spring, thereby realizing the online monitoring function of the contact pressure of the isolating switch contacts, converting the detected signal and sending it out, solving the high-voltage insulation problem of the sensor and providing technical support for the intelligent upgrade of the inflatable cabinet.

[0014] Furthermore, the isolation knife switch 1 is arranged in a sealed housing, and a sealing plug 7 is provided on the housing for the wireless line signal emitted by the wireless signal transmitter 14 to penetrate.

[0015] Since the signal transmitter is sealed in a stainless steel air chamber, the wireless digital signal cannot be transmitted out of the sealed metal shell. By providing a sealing plug cover on the shell, the wireless digital signal can be transmitted out of the shell.

[0016] Furthermore, the stress sensor is a shaft pin sensor 16, which is arranged at a position capable of sensing the pressure generated on the contact pressure spring when the isolation knife switch rotates.

[0017] Furthermore, the axle pin sensor 16 passes through the sensor sleeve 15 laterally, and the end face of the contact pressure spring 18 presses on the washer 17, transferring the pressure to the washer 17. The washer 17 presses the sensor sleeve 15, so that the sensor sleeve 15 applies a radial shear stress to the axle pin sensor 16. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall structure of the three-position disconnector of the present invention;

[0019] Figure 2It is a structural schematic diagram of the isolating knife switch of the three-position isolating switch of the present invention;

[0020] Figure 3 It is a partial structural diagram of the three-position disconnector of the present invention;

[0021] Among them, 1 is the isolating knife switch; 2 is the grounding contact seat; 3 is the grounding copper busbar; 4 is the upper outlet bushing; 5 is the stainless steel sealing box; 6 is the insulating pull rod; 7 is the sealing plug cover; 8 is the sealed transmission shaft; 9 is the first gear; 10 is the mechanism support frame; 11 is the operating mechanism; 12 is the upper static contact; 13 is the isolating knife switch body; 14 is the wireless signal transmitter; 15 is the sensor spacer; 16 is the shaft pin sensor; 17 is the gasket; 18 is the contact pressure spring; 19 is the lower static contact; 20 is the isolating switch transmission main shaft; 21 is the upper static contact support insulator; 22 is the mechanism output shaft; 23 is the second gear; 24 is the stud pin; 25 is the nut; 26 is the isolating switch transmission main shaft bevel gear; 27 is the sealed transmission shaft bevel gear. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0023] Embodiment of three-position disconnect switch

[0024] A high-voltage three-position disconnector has three positions: isolation-on, opening, and earthing. The isolation position, after opening, creates a reliable insulation barrier in the power system, isolating the equipment or circuit requiring maintenance from the power source with a clear disconnect point to ensure the safety of maintenance personnel and equipment. In the closed position, it carries the rated current of the normal circuit and the rated short-circuit current for a specified time. The earthing switch is a mechanical grounding device that discharges static charge from the equipment and circuit being maintained, as well as ensuring the safety of maintenance personnel during power outages. It can withstand short-circuit currents for a specified period of time. Whether an disconnector can stably and reliably carry the rated current of the normal circuit and the rated short-circuit current depends not only on the cross-sectional dimensions of the disconnector conductor meeting requirements but also on sufficient contact pressure between the disconnector contacts. Insufficient contact pressure can lead to severe heating of the circuit conductor and aging of the insulation material. Insufficient contact pressure can also reduce the rated short-circuit current withstand capability, potentially causing contact welding when a short-circuit current occurs. Therefore, contact pressure is a key parameter for disconnector reliability. The contact pressure is maintained by the contact compression spring. Mechanical fatigue of the spring is the main reason for insufficient contact pressure. Contact pressure monitoring is an effective way to improve the reliability of the disconnector.

[0025] The present invention adds a contact pressure monitoring device to the existing three-position disconnector. Rotation of the disconnector creates pressure on a spring, which in turn generates shear stress on a stress sensor. This shear stress changes the strain gauge resistance of the stress sensor, thereby detecting the disconnector contact pressure. This is explained below with reference to a specific example.

[0026] The overall structural diagram of the present invention is as follows Figure 1 As shown, the three-position disconnector of the present invention includes an isolating knife switch 1, a grounding contact seat 2, a grounding copper bar 3, an upper outlet bushing 4, a stainless steel sealed box 5, an insulating pull rod 6, a sealed transmission shaft 8, a first gear 9, a mechanism support frame 10, an operating mechanism 11, an upper static contact support insulator 21, a mechanism output shaft 22, a second gear 23, and a sealed transmission shaft bevel gear 27. The second gear 23 is fixed to the mechanism output shaft 22, the second gear 23 is engaged with the first gear 9, the first gear 9 is fixed to the sealed transmission shaft 8, the rotational motion of the mechanism output shaft 23 is transmitted to the sealed transmission shaft 8 through the engagement of the second gear 23 with the first gear 9, the sealed transmission shaft bevel gear 27 is engaged with the disconnector transmission main shaft bevel gear 26 to realize the rotational motion of the disconnector main shaft, the disconnector main shaft drives the insulating pull rod 6 through the crank arm, and the insulating pull rod 6 drives the disconnector knife switch 1 to realize the three positions of the disconnector knife switch 1: opening, closing, and grounding. The structural schematic diagram of the disconnector knife switch of the three-position disconnector is shown as follows Figure 2 As shown, the three-position disconnector also includes an upper static contact 12, an isolating knife switch body 13 (the same structure as the isolating knife switch 1, just from a different perspective), a contact pressure spring 18, a lower static contact 19, an isolating switch transmission main shaft 20, and an isolating switch transmission main shaft bevel gear 26. The isolating knife switch is provided with a stud pin 24 and a nut 25 for cooperating to realize the rotation of the isolating knife switch 1. The contact pressure between the isolating knife switch body 13 and the upper static contact 12 and the lower static contact 19 is maintained by the contact pressure spring 18. The local structure of the three-position disconnector is shown in FIG. Figure 3 shown.

[0027] The contact pressure monitoring device of the present invention includes a wireless signal transmitter 14, a sensor spacer 15, a stress sensor, and a washer 17. The stress sensor in this embodiment adopts an axle pin sensor 16. The end face of the contact pressure spring 18 is pressed on the washer 17, transmitting the pressure to the washer 17. The washer 17 presses the sensor spacer 15. The axle pin sensor 16 passes through the sensor spacer 15 horizontally, so that the sensor spacer 15 applies a radial shear stress to the axle pin sensor 16.

[0028] Radial shear stress causes the strain resistance value of the pin sensor 16 to change; the wireless signal transmitter 14 is in communication with the pin sensor 16 and is used to convert the strain resistance value into a wireless digital signal. Because the isolation switch 1 and its contact pressure monitoring device are both disposed within a sealed housing, the wireless signal transmitter 14 smoothly transmits the converted wireless digital signal to the monitoring portion outside the housing. The present invention also provides a sealing plug 7 on the sealed housing. This sealing plug 7 enables the wireless digital signal emitted by the wireless signal transmitter 14 to be transmitted to the exterior of the housing. The sealing plug 7 in this embodiment is made of organic glass and can be provided as one or more plugs.

[0029] In this embodiment, the electrical signal collected by the axle pin sensor 16 can be transmitted via wired or wireless means. Since the isolating knife switch is a high-voltage conductor, the use of wired signals requires solving the insulation problem of the signal transmission line. Therefore, this embodiment adopts wireless signal transmission. The wireless signal transmitter 14 converts the strain resistance value into a wireless digital signal and sends it. Since the three-position isolating switch is used in a 35KV gas cabinet, the gas cabinet is to install the high-voltage components of each functional unit in a sealed SF6 gas tank. The SF6 gas tank is a metal sealed box. Therefore, in this embodiment, the wireless digital signal is sent to the external terminal receiver through the sealing cover 7 on the shell. In this embodiment, Zigbee wireless digital signals are used. As other implementations, other methods such as Bluetooth and WiFi can also be used for signal transmission.

[0030] This invention achieves online contact pressure monitoring through the coordinated operation of a pin sensor, sensor spacer, wireless signal transmitter, and terminal receiver. Because the isolation switch is a high-voltage conductor, using a wired signal requires insulation of the signal transmission line. This invention uses ZigBee wireless digital signals to address this high-voltage insulation issue.

[0031] Embodiments of a contact pressure monitoring device

[0032] The contact pressure monitoring device includes a stress sensor and a wireless signal transmitter. The stress sensor senses the pressure exerted on the spring by the isolating switch during rotation. The wireless signal transmitter is in communication with the stress sensor and converts the electrical signal detected by the stress sensor into a wireless digital signal. The specific implementation of this device has been detailed in the embodiment of the three-position isolating switch and will not be repeated here.

Claims

1. A three-position isolating switch, comprising an isolating knife switch (1), an insulating pull rod (6), and a contact pressure spring (18), wherein the insulating pull rod (6) drives the isolating knife switch (1) to realize the three positions of the isolating knife switch (1) being open, closed, and grounded, and characterized in that: It also includes a stress sensor capable of sensing the pressure of the contact pressure spring (18) when the isolating knife switch (1) rotates to generate pressure on the contact pressure spring (18).

2. The three-position disconnect switch according to claim 1, characterized in that: The stress sensor is an axle pin sensor (16), which passes through the sensor sleeve (15) transversely. The end face of the contact pressure spring (18) is pressed on the washer (17), transmitting the pressure to the washer (17). The washer (17) presses the sensor sleeve (15), so that the sensor sleeve (15) applies a radial shear stress to the axle pin sensor (16).

3. The three-position disconnect switch according to claim 1 or 2, characterized in that: The three-position isolating switch further comprises a wireless signal transmitter (14) connected to the stress sensor and used for converting the electrical signal detected by the stress sensor into a wireless digital signal.

4. The three-position disconnect switch according to claim 3, characterized in that: The isolation knife switch (1) is arranged in a sealed housing, and a sealing plug (7) is provided on the housing for the wireless line signal emitted by the wireless signal transmitter (14) to penetrate.

5. A contact pressure monitoring device, characterized in that: The invention comprises a stress sensor and a wireless signal transmitter (14). The stress sensor is used to sense the pressure generated on the contact pressure spring when the isolation knife switch (1) rotates. The wireless signal transmitter is connected to the stress sensor for communication and is used to convert the electrical signal detected by the stress sensor into a wireless digital signal.

6. The contact pressure monitoring device according to claim 5, characterized in that: The isolation knife switch (1) is arranged in a sealed housing, and a sealing plug (7) is provided on the housing for the wireless line signal emitted by the wireless signal transmitter (14) to penetrate.

7. The contact pressure monitoring device according to claim 5 or 6, characterized in that: The stress sensor is a shaft pin sensor (16) which is arranged at a position capable of sensing the pressure generated on the contact pressure spring when the isolation knife switch rotates.

8. The contact pressure monitoring device according to claim 7, characterized in that: The axle pin sensor (16) passes through the sensor spacer (15) transversely, and the end face of the contact pressure spring (18) presses on the washer (17), transmitting the pressure to the washer (17). The washer (17) presses the sensor spacer (15), so that the sensor spacer (15) applies a radial shear stress to the axle pin sensor (16).

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