Isolation switch insulator stress alarm system

Abstract

The invention relates to an isolation switch insulator stress alarm system. An isolation switch comprises a base, an insulator installed at the upper end of the base and a stand column installed at the lower end of the base. The bottom of the insulator is fixed with the base through the matching of a flange, a pair of symmetrically distributed strain gauges are connected to the two sides of the bottom of the insulator, and the strain gauges are parallel to the center line of the insulator; the stand column is further provided with an alarm box, and a voltage detector, an alarm device and a pair of resistors are arranged in the alarm box. The two strain gauges and the two resistors are connected through a circuit to form a Wheatstone bridge, the Wheatstone bridge is connected to a power supply, the two sides of the Wheatstone bridge are connected to the input end of the voltage detector, and the output end of the voltage detector is connected to the alarm. The alarm system is simple in structure, stable in performance and low in cost, and can solve the problem that the disconnecting switch insulator is large in bending force and has no early warning due to internal or external factors during outdoor operation.

Description

Technical Field

[0001] This invention relates to the field of disconnector switch monitoring, and in particular to a stress alarm system for disconnector switch insulators. Background Technology

[0002] A disconnecting switch is a switching device primarily used for isolating power sources, switching operations, and connecting and disconnecting small-current circuits, without arc-extinguishing capabilities. When in the open position, the contacts of a disconnecting switch have an insulation distance meeting specified requirements and a clear disconnection mark; when in the closed position, it can carry current under normal circuit conditions and current under abnormal conditions (such as short circuits) for a specified time. It is generally used as a high-voltage disconnecting switch, i.e., a disconnecting switch with a rated voltage of 1kV or higher. Its working principle and structure are relatively simple, but due to its large usage and high reliability requirements, it has a significant impact on the design, construction, and safe operation of substations and power plants. The main characteristic of a disconnecting switch is that it lacks arc-extinguishing capability and can only open and close circuits when there is no load current. This entry introduces the functions, characteristics, types, applications, anti-misoperation improvements, maintenance, and common problems of disconnecting switches.

[0003] Currently, conventional disconnect switches do not have the ability to monitor and alarm in real time the stress on insulators. Under conditions such as improper operation, foundation settlement, strong winds, or earthquakes, disconnect switches may be subjected to large bending stress and break, leading to serious power outages and affecting the safe operation of the entire power grid. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a stress alarm system for disconnecting switch insulators that can monitor the stress on disconnecting switches in real time.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a force alarm system for disconnecting switch insulators, the innovation of which is: the disconnecting switch includes a base, an insulator installed on the upper end of the base, and a column installed on the lower end of the base; The bottom of the insulator is fixed to the base by a flange. A pair of symmetrically distributed strain gauges are connected to both sides of the bottom of the insulator, and the strain gauges are parallel to the center line of the insulator. An alarm box is also installed on the column, and the alarm box contains a voltage detector, an alarm and a pair of resistors; The two strain gauges and two resistors are connected by a circuit to form a Wheatstone bridge and connected to a power supply. The input terminals of a voltage detector are connected to both sides of the Wheatstone bridge, and the output terminal of the voltage detector is connected to an alarm.

[0006] Furthermore, the two strain gauges are vertically mounted on both sides of the insulator, and both strain gauges are located on the upper end face of the flange.

[0007] Furthermore, the alarm method of the disconnector insulator stress alarm system includes the following steps: First, the maximum allowable stress at the root of the insulator is calculated based on the insulator's height, rod diameter, and rated bending strength. This stress is then converted into the maximum allowable strain, and the corresponding voltage value is calculated. The voltage detector then sets this voltage value to the set voltage value. Secondly, a pair of symmetrically distributed strain gauges are attached to both sides of the upper end face of the bottom flange of the insulator. The two strain gauges are in the same environment, so there is no need for temperature compensation. The strain measured by the two strain gauges is taken as the strain at the root of the insulator. Then, two strain gauges are used to detect the strain at the root of the insulator, and the detection results are converted into real-time voltage values. These real-time voltage values ​​are then fed back to the voltage detector, which compares the real-time voltage values ​​with the set voltage values. Finally, when the voltage detector determines that the insulator stress has reached the maximum allowable stress, the alarm will issue an alarm signal.

[0008] Furthermore, the voltage value is calculated as follows: First, define the resistance as R, the power supply as E, and the resistances of the two strain gauges as R1 and R2, respectively. When the bending stress of the insulator increases, the resistance of the strain gauges will change by ΔR. At this time, the voltage across the voltage detector of the two strain gauges is... 1) When the voltage U exceeds the set value, the output voltage of the voltage detector causes the alarm to issue an alarm signal; The calculation method for the set voltage value of the voltage detector is as follows: Assuming the diameter of the insulator root rod is D, the height is H, the allowable stress of the insulator is 40 MPa, the bending strength of the insulator is F, and the elastic modulus of the insulator is G, then the allowable strain gauge variation ΔR 许 for: 2) Substituting the value of equation 2) into equation 1) yields the set voltage value.

[0009] The advantages of this invention are: the alarm system of this invention has a simple structure, stable performance, and low cost, and can solve the problem of no early warning when the insulator of the disconnecting switch is subjected to large bending force due to internal or external factors during outdoor operation.

[0010] The alarm system of this invention can monitor the stress on the insulator in real time, and can preset the alarm force value of the insulator according to the rod diameter and height of the insulator. This allows for early detection of the bending force received by the disconnecting switch, enabling preventive measures to be taken in advance to ensure the safe and stable operation of the substation. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the disconnector switch insulator stress alarm system of the present invention.

[0012] Figure 2 This is a circuit connection diagram for the present invention. Detailed Implementation

[0013] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0014] like Figure 1 , Figure 2 The diagram shows a stress alarm system for a disconnecting switch insulator. The disconnecting switch includes a base 5, an insulator 3 mounted on the upper end of the base 5, and a column 7 mounted on the lower end of the base 5.

[0015] The bottom of the insulator 3 is fixed to the base through the fit of the flange 4. A pair of symmetrically distributed strain gauges are connected on both sides of the bottom of the insulator 3, and the strain gauges are parallel to the center line of the insulator 3. The two strain gauges are defined as the first strain gauge 1 and the second strain gauge 2, respectively.

[0016] The first strain gauge 1 and the second strain gauge 2 are vertically installed on both sides of the insulator 3, and both the first strain gauge 1 and the second strain gauge 2 are located on the upper end face of the flange 4.

[0017] An alarm box 6 is also installed on the column 7. Inside the alarm box 6 are a voltage detector 63, an alarm 64 and a pair of resistors 61.

[0018] like Figure 2 As shown, the first strain gauge 1 and the second strain gauge 2 are respectively connected to two resistors 61 through a circuit to form a Wheatstone bridge, and are connected to a power supply 62. The input terminals of voltage detectors 63 are connected to both sides of the Wheatstone bridge, and the output terminal of voltage detectors 63 is connected to an alarm 64.

[0019] The alarm method of the disconnector switch insulator stress alarm system includes the following steps: First, the maximum allowable stress at the root of the insulator is calculated based on the height of insulator 3, the rod diameter, and the rated bending strength of the insulator. This stress is then converted into the maximum allowable strain, and the corresponding voltage value is calculated. The voltage detector then sets this voltage value to the set voltage value.

[0020] The voltage value is calculated as follows: First, define resistor 61 as R, power supply 62 as E, and the resistances of the first strain gauge 1 and the second strain gauge 2 as R1 and R2, respectively. When the bending stress of the insulator 3 increases, the resistances of the first strain gauge 1 and the second strain gauge 2 will change by ΔR. At this time, the voltage across the voltage detector 63 is... 1) When the voltage U exceeds the set value, the output voltage of the voltage detector 63 causes the alarm 64 to issue an alarm signal.

[0021] The calculation method for the set voltage value of the voltage detector is as follows: Assume the diameter of the rod at the root of insulator 3 is D, the height is H, the allowable stress of insulator 3 is 40 MPa, the bending strength of insulator 3 is F, and the elastic modulus of insulator 3 is G. Then the allowable strain gauge variation ΔR 许 for: 2) Substituting the value of equation 2) into equation 1) yields the set voltage value.

[0022] Secondly, a pair of symmetrically distributed strain gauges are attached to both sides of the upper end face of the bottom flange 4 of the insulator 3. The two strain gauges are in the same environment, so there is no need for temperature compensation. The strain measured by the two strain gauges is taken as the strain at the root of the insulator 3.

[0023] Then, the strain at the root of the insulator 3 is detected by two strain gauges, and the detection results are converted into real-time voltage values. These real-time voltage values ​​are then fed back to the voltage detector 63, which compares the real-time voltage values ​​with the set voltage values.

[0024] Finally, when the voltage detector 63 determines that the stress on the insulator 3 has reached the maximum allowable stress, the alarm device 64 will issue an alarm signal to prompt the user to conduct timely inspection and take preventive measures.

[0025] The alarm system of this invention can monitor the stress on insulators in real time and can preset the alarm force value of the insulators according to the rod diameter and height of the insulators. This allows for early detection of the bending force received by the disconnecting switch, enabling preventive measures to be taken in advance to ensure the safe and stable operation of the substation. This alarm system can be applied to the detection of stress on the insulators of high-voltage disconnecting switches in substations.

[0026] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A disconnector insulator stress warning system, characterized in that: The isolating switch comprises a base, an insulator installed at the upper end of the base, and a stand installed at the lower end of the base; The bottom of the insulator is fixed to the base by the cooperation of the flanges, and a pair of symmetrically distributed strain gauges are connected to the two sides of the bottom of the insulator, and the strain gauges are parallel to the center line of the insulator; The stand is further provided with an alarm box, and the alarm box is provided with a voltage detector, an alarm, and a pair of resistors; The two strain gauges and the two resistors are connected by a circuit to form a Wheatstone bridge, and are connected to a power supply, the two sides of the Wheatstone bridge are connected to the input end of the voltage detector, and the output end of the voltage detector is connected to the alarm.

2. The isolator insulator stress warning system of claim 1, wherein: The two strain gauges are vertically installed on the two sides of the insulator, and the two strain gauges are located at the upper end surface position of the flanges.

3. The isolator insulator stress warning system of claim 1, wherein: The alarm method of the isolating switch insulator stress alarm system comprises the following steps: First, the maximum allowable stress of the insulator root is calculated according to the height of the insulator, the rod diameter, and the rated bending strength of the insulator, and is converted into the maximum allowable strain, the corresponding voltage value is calculated, and the voltage value is set as the set voltage value by the voltage detector; Second, a pair of symmetrically distributed strain gauges are attached to the upper end surface of the flange at the bottom of the insulator, and the two strain gauges are in the same environment, so temperature compensation is not required, and the strain measured by the two strain gauges is used as the strain of the insulator root; Then, the strain of the insulator root is detected by the two strain gauges, and the detection result is converted into a real-time voltage value, and the real-time voltage value is fed back to the voltage detector, and the voltage detector compares the real-time voltage value with the set voltage value; Finally, when the insulator stress reaches the maximum allowable stress according to the comparison result of the voltage detector, the alarm sends an alarm signal.

4. The disconnector insulator stress warning system according to claim 3, characterized in that: The calculation method of the voltage value is as follows: First, define the resistance as R, the power supply as E, and the resistance of the two strain gauges as R1 and R2, when the bending stress of the insulator increases, the resistance of the strain gauge changes by△R, and the voltage across the voltage detector at this time is 1） When the voltage U exceeds the set value, the output voltage of the voltage detector causes the alarm to send an alarm signal; The calculation method of the set voltage value of the voltage detector is: setting the root rod diameter of the insulator as D, the height as H, the allowable stress of the insulator as 40 MPa, the bending strength of the insulator as F, and the elastic modulus of the insulator as G, then the allowed strain gauge variation ΔR is 许 : 2） The value of formula 2) is brought into formula 1) to obtain the set voltage value.

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