A method for diagnosing mechanical defects of a double-column horizontal opening isolating switch

Abstract

The present application belongs to the technical field of defect detection methods for power equipment, and in particular, to a method for diagnosing mechanical defects of a double-column horizontal opening type disconnector. First, a closing stroke curve is constructed based on a normally operating double-column horizontal opening type disconnector to obtain corresponding data of a normal stroke curve; during the closing process of the double-column horizontal opening type disconnector to be tested, a measured closing stroke curve is drawn. Fault identification and detection are performed based on the difference between the measured curve and the normal curve. The present invention uses a digital quantitative method to quickly and effectively judge various mechanical defects of the double-column horizontal opening type disconnector, which helps to improve the efficiency and accuracy of diagnosing mechanical defects of the disconnector, improve the reliability of the operation of the disconnector, and provide a design basis for realizing digital intelligent monitoring. Based on this method and its judgment rules, sensors and other equipment can be conveniently used to realize automatic monitoring and alarming, which is convenient for industrial implementation and has good application prospects.

Description

Technical Field

[0001] The present application belongs to the technical field of power equipment defect detection methods, and in particular, relates to a double-column horizontal opening isolating switch and a mechanical defect diagnosis method. Background Art

[0002] High-voltage disconnectors are the most numerous switchgear in power plants and substations. They have various structural forms such as horizontal and vertical, and have functions such as isolating power supply, switching operation, connecting and disconnecting low-current circuits, etc. During the installation and operation of disconnectors, affected by the installation and commissioning experience and harsh environment (rain, ice, sand), there may be potential defects such as bearing jamming, operating rod jamming, contact rust, insufficient clamping force, three-phase sync, spring failure, and inadequate travel. It is difficult to detect defects in time through manual separation and closing tests at the early stage, resulting in rotating insulator fracture, transmission rod deformation, contact finger deformation, poor contact, local overheating, separation and closing failure, etc. The commonly used diagnostic method currently uses a torque wrench. When using a torque wrench to detect mechanical defects, its effectiveness mainly depends on the experience of maintenance personnel. This method is not easy to detect general defects in the early stage, which will cause the disconnector to operate with defects. Typical defects such as three-phase sync, contact angle deviation, and over-travel can all lead to poor contact, contact fatigue, contact overheating, etc., which reduces the reliability and service life of the switchgear. Summary of the invention

[0003] The purpose of the invention is to adopt a digital method to replace the manual torque wrench method to improve the sensitivity and accuracy of mechanical defect diagnosis of a double-column horizontal opening disconnector.

[0004] To achieve the above purpose, the present invention adopts the following technical solution.

[0005] A method for diagnosing mechanical defects of a double-column horizontal opening disconnector, the method for diagnosing mechanical defects of a double-column horizontal opening disconnector is based on a closing stroke curve, the closing stroke curve is set in a cross coordinate system, wherein the abscissa coefficient is the rotation angle of an operating rod during the closing process; wherein the ordinate coefficient is the torque of the operating rod during the closing process;

[0006] Firstly, a closing stroke curve is constructed according to the normally operating double-column horizontal opening isolating switch, and the corresponding data of the normal stroke curve is obtained;

[0007] The sections are divided according to the changing trend of closing torque, including:

[0008] The smoothing interval x∈[α0, α1] of the contact travel process;

[0009] The small wave peak section x∈[α1, α2] of the contact process;

[0010] The large peak section x∈[α2, α3] of the contact engagement process;

[0011] During the closing process of the double-column horizontal opening disconnector to be tested, the rotation angle of the operating lever and the torque data of the operating lever during the closing process are measured, and the measured closing stroke curve is drawn.

[0012] Based on the above, the similarity coefficient R is defined as follows:

[0013] Assume that the measured closing stroke curve and normal stroke curve are sequence X(k) and sequence Y(k), respectively, k = 0, 1, ..., N-1, where X(k) and Y(k) are real numbers, and N is the number of sampling points;

[0014] Compute the standard deviation of these two series:

[0015]

[0016] Compute the covariance of these two series:

[0017]

[0018] Compute the normalized covariance coefficient of the two series:

[0019]

[0020] Calculate the similarity coefficient R:

[0021]

[0022] For the travel stage between the rotation angles α0 and α1, a similarity comparison is performed between the measured closing travel curve within the range and the normal travel curve. If the similarity coefficient is less than R1, and R1 is taken as 2.0, it is judged that the double-column horizontal opening disconnector has a jamming defect in the travel stage.

[0023] For the contact stage between the rotation angles α1 and α2, the measured curve within this range is compared with the normal stroke curve for similarity. If the similarity coefficient is less than R2, and the R2 value is 1.5, it is judged that the double-column horizontal opening disconnector has a three-phase out-of-phase defect in the contact stage;

[0024] For the engagement stage between the rotation angles α2 and α3, if the terminal torque of the measured curve within this range exceeds R3 times the average torque of the travel stage, and R3 is 1.3, it is judged that the double-column horizontal opening type disconnector has a closing overtravel defect in the engagement stage.

[0025] Based on the aforementioned double-column horizontal opening disconnector mechanical defect diagnosis method, the normal travel curve construction method is: construct a finite element simulation according to the double-column horizontal opening disconnector to be diagnosed, and obtain the normal travel curve based on the simulated closing process of the finite element model of the horizontal opening disconnector.

[0026] Based on the aforementioned closing mechanical defect diagnosis method of the double-column horizontal opening type disconnector, the normal stroke curve construction method is: measuring the closing stroke curve of the double-column horizontal opening type disconnector in normal operation to obtain the normal stroke curve.

[0027] Based on the aforementioned closing mechanical defect diagnosis method of the double-column horizontal opening type disconnector, the normal stroke curve construction method is: theoretically deriving the closing stroke curve of the normally operating double-column horizontal opening type disconnector to obtain the normal stroke curve.

[0028] Based on the aforementioned double-column horizontal opening disconnector mechanical defect diagnosis method, its diagnosis range is in the engagement stage between the rotation angles α2 and α3. The terminal angle of the measured curve within this range is compared with the terminal angle of the normal stroke curve. If the measured angle is less than the normal stroke angle by more than R4, and R4 takes a value of 3°, it is judged that the double-column horizontal opening disconnector has a closing under-travel defect in the engagement stage.

[0029] Based on the aforementioned double-column horizontal opening disconnector mechanical defect diagnosis method, its diagnosis range is in the engagement stage between the rotation angles α2 and α3. The terminal angle of the measured curve within this range is compared with the terminal angle of the normal stroke curve. If the measured angle is greater than the normal stroke angle by more than R5, and R5 is taken as 3°, it is judged that the double-column horizontal opening disconnector has a closing overtravel defect in the engagement stage.

[0030] Its beneficial effects are:

[0031] The present invention uses a digital quantitative method to quickly and effectively judge various mechanical defects of double-column horizontal opening isolating switches, which helps to improve the diagnostic efficiency and accuracy of mechanical defects of isolating switches, improve the reliability of isolating switch operation, and provide a design basis for realizing digital intelligent monitoring. Based on this method and its judgment rules, sensors and other equipment can be conveniently used to realize automatic monitoring and alarm, which is convenient for industrial implementation and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the closing stroke curve. DETAILED DESCRIPTION

[0033] The present invention is described in detail below in conjunction with specific embodiments.

[0034] The double-column horizontal opening disconnector closing mechanical defect diagnosis method of the present application is based on the closing stroke curve, such as Figure 1 As shown, the closing stroke curve is set in a cross coordinate system, where the abscissa coefficient is the rotation angle of the operating lever during the closing process (°); and the ordinate coefficient is the closing torque during the closing process (Nm);

[0035] Firstly, a closing stroke curve is constructed according to the normally operating double-column horizontal opening isolating switch, and the corresponding data of the normal stroke curve is obtained;

[0036] The sections are divided according to the changing trend of closing torque, including:

[0037] The smoothing interval x∈[α0, α1] of the contact travel process;

[0038] The small wave peak section x∈[α1, α2] of the contact process;

[0039] The large peak section x∈[α2, α3] of the contact engagement process;

[0040] In order to simplify the implementation process and improve efficiency, finite element modeling and simulation can be used to simulate the closing process and obtain the normal travel curve using the finite model of the device under test.

[0041] During the closing process of the double-column horizontal opening disconnector to be tested, the rotation angle of the operating lever and the closing torque data during the closing process are measured, and the measured closing stroke curve is drawn. On this basis, the mechanical fault is judged according to the following method:

[0042] The similarity between the measured closing stroke curve and the normal stroke curve is quantitatively calculated by the stroke curve similarity coefficient R, which can be used as a basis for judging whether there are mechanical defects in the transmission mechanism of the double-column horizontal opening disconnector.

[0043] Assume that the measured closing stroke curve and the normal stroke curve are X(k) and Y(k) respectively, k=0, 1, ..., N-1, where X(k) and Y(k) are real numbers and N is the number of sampling points. The similarity coefficient R can be calculated according to the following formula.

[0044] Compute the standard deviation of two series:

[0045]

[0046] Compute the covariance of two series:

[0047]

[0048] Compute the normalized covariance coefficient of two series:

[0049]

[0050] Calculate the similarity coefficient R:

[0051]

[0052] For the travel stage between the rotation angles α0 and α1, the measured closing travel curve within the range is compared with the normal travel curve for similarity. If the similarity coefficient is less than 2.0, it is determined that the double-column horizontal opening disconnector has a jamming defect in the travel stage;

[0053] For the contact stage between the rotation angles α1 and α2, the measured curve within this range is compared with the normal stroke curve for similarity. If the similarity coefficient is less than 1.5, it is determined that the double-column horizontal opening disconnector has a three-phase out-of-phase defect during the contact stage.

[0054] For the engagement stage between the rotation angles α2 and α3, if the terminal torque of the measured curve within this range exceeds 1.3 times the average torque of the travel stage, it is judged that the double-column horizontal opening type disconnector has a closing overtravel defect in the engagement stage.

[0055] For the engagement stage between the rotation angles α2 and α3, the terminal angle of the measured curve within this range is compared with the terminal angle of the normal travel curve. If the measured angle is smaller than the simulation angle by more than 3°, it is judged that the double-column horizontal opening disconnector has a closing under-travel defect during the engagement stage.

[0056] For the engagement stage between the rotation angles α2 and α3, the terminal angle of the measured curve within this range is compared with the terminal angle of the normal stroke curve. If the measured angle is greater than the simulation angle by more than 3°, it is judged that the double-column horizontal opening disconnector has a closing overtravel defect during the engagement stage.

[0057] according to Figure 1 The switch stroke curve to be tested is combined with the method proposed in this application to analyze and diagnose the closing stroke curve of the double-column horizontal opening type disconnector shown in the above figure.

[0058] In the travel stage before the contact fingers engage, the closing torque drives the main knife to rotate at a basically uniform speed. It is a translational rotation process. Under normal circumstances, its torque curve is smooth.

[0059] After similarity coefficient calculation, the similarity coefficient is 1.8, indicating that the disconnector has a stuck defect in this travel stage. During the actual measurement, the transmission component or the ground knife of the disconnector was not properly debugged, so that the two touched during the movement, proving that the judgment conclusion of the defect is correct.

[0060] In the contact stage, the measured curve and the simulation curve in this range are compared for similarity, and the calculated similarity coefficient is 2.3, indicating that the double-column horizontal opening disconnector does not have the defect of three-phase synch during the contact stage. In the meshing stage, the simulation value of the main shaft rotation angle during the operation of this model switch is 135°, while the actual value of the switch rotation angle is 147°, which exceeds the simulation angle by 12°, and can be diagnosed as a closing overtravel defect. In the actual measurement, the mechanical limit of this case did not play the role of double protection, which was caused by improper operation of the travel switch and mechanical limit device of the mechanism box.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for diagnosing mechanical defects of a double-column horizontal opening disconnector, characterized in that: The closing mechanical defect diagnosis method of the double-column horizontal opening disconnector is based on the closing stroke curve, which is set in a cross coordinate system, where the abscissa coefficient is the rotation angle of the operating lever during the closing process, and the ordinate coefficient is the torque of the operating lever during the closing process; Firstly, a closing stroke curve is constructed according to the normally operating double-column horizontal opening isolating switch, and the corresponding data of the normal stroke curve is obtained; The sections are divided according to the changing trend of closing torque, including: The smoothing interval x∈[α0, α1] of the contact travel process; The small wave peak section x∈[α1, α2] of the contact process; The large peak section x∈[α2, α3] of the contact engagement process; During the closing process of the double-column horizontal opening disconnector to be tested, the rotation angle and torque data of the operating lever during the closing process are measured, and the measured closing stroke curve is drawn; Based on the above, the similarity coefficient R is defined as follows: Assume that the measured closing stroke curve and normal stroke curve are sequence X(k) and sequence Y(k), respectively, k = 0, 1, ..., N-1, where X(k) and Y(k) are real numbers, and N is the number of sampling points; Compute the standard deviation of these two series: Compute the covariance of these two series: Compute the normalized covariance coefficient of the two series: Calculate the similarity coefficient R: For the travel stage between the rotation angles α0 and α1, the measured closing travel curve within the range is compared with the normal travel curve for similarity. If the similarity coefficient is less than R1, and R1 is 2.0, it is determined that the double-column horizontal opening disconnector has a jamming defect in the travel stage; For the contact stage between the rotation angles α1 and α2, the measured curve within this range is compared with the normal stroke curve for similarity. If the similarity coefficient is less than R2, and the R2 value is 1.5, it is judged that the double-column horizontal opening disconnector has a three-phase out-of-phase defect in the contact stage; For the engagement stage between the rotation angles α2 and α3, if the terminal torque of the measured curve within this range exceeds R3 times the average torque of the travel stage, and R3 is 1.3, it is judged that the double-column horizontal opening type disconnector has a closing overtravel defect in the engagement stage.

2. According to claim 1, a method for diagnosing mechanical defects of a double-column horizontal opening disconnector is characterized in that: The normal travel curve construction method is: construct a finite element simulation according to the double-column horizontal opening disconnector to be diagnosed, and obtain the normal travel curve based on the simulated closing process of the finite element model of the horizontal opening disconnector.

3. According to claim 1, a method for diagnosing mechanical defects of a double-column horizontal opening disconnector is characterized in that: The normal travel curve construction method is: measuring the closing travel curve of the normally operating double-column horizontal opening type disconnector to obtain the normal travel curve.

4. A method for diagnosing mechanical defects of a double-column horizontal opening disconnector according to claim 1, characterized in that: The method for constructing the normal travel curve is as follows: theoretically deriving the closing travel curve of a normally operating double-column horizontal opening type disconnector to obtain the normal travel curve.

5. According to claim 1, a method for diagnosing mechanical defects of a double-column horizontal opening disconnector is characterized in that Its diagnostic range is in the meshing stage between the rotation angles α2 and α3. The terminal angle of the measured curve within this range is compared with the terminal angle of the normal stroke curve. If the measured angle is smaller than the normal stroke angle by more than R4, and R4 takes a value of 3°, it is judged that the double-column horizontal opening disconnector has a closing under-travel defect in the meshing stage.

6. A method for diagnosing mechanical defects of a double-column horizontal opening disconnector according to claim 1, characterized in that Its diagnostic range is in the meshing stage between the rotation angles α2 and α3. The terminal angle of the measured curve within this range is compared with the terminal angle of the normal stroke curve. If the measured angle is greater than the normal stroke angle by more than R5, and R5 takes a value of 3°, it is judged that the double-column horizontal opening disconnector has a closing overtravel defect in the meshing stage.

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