A Mechanical Fault Diagnosis Method for Disconnecting Switches with Multi-Information Parameter Fusion

Abstract

The present invention discloses a mechanical fault diagnosis method for isolating switches with multi-information parameter fusion. First, the changes in corresponding characteristic quantities during the opening or closing operation of the isolating switch are measured by sensors such as torque, rotation angle, and current, and torque-time (or torque-rotation angle), current-time curves, etc. are constructed. Then, according to the above curves, the effective values, average values, maximum values, etc. of characteristic quantities such as torque and current within one action cycle (one opening or closing) are respectively solved and obtained. Finally, the ratio of the maximum value (or effective value) of the above characteristic quantity to the average value is defined as its curve coefficient, and the mechanical state recognition and mechanical fault diagnosis of the isolating switch are realized according to the numerical situation of the curve coefficient. The present invention can replace the commonly used horizontal and vertical comparison methods in existing fault diagnosis methods, eliminate the dependence of the diagnosis method on measurement samples in different operating states, and at the same time improve the generality of the method in isolating switches of different structural types.

Description

Technical Field

[0001] The present invention relates to the technical field of disconnector state detection and fault diagnosis, and particularly relates to a mechanical fault diagnosis method for disconnectors that fuses multi-information parameters. Background Art

[0002] High-voltage disconnectors are important switching devices in the power grid. Due to their large usage and high requirements for working reliability, their state assessment and fault diagnosis technologies have attracted the attention of power operation and maintenance units. Existing mechanical fault diagnosis methods for disconnectors mainly rely on characteristic quantities such as infrared temperature measurement, motor current, torque, and rotation angle. Among them, infrared temperature measurement is mainly used to detect possible poor contact defects of contact fingers in the off state of the disconnector, and the latter three mainly judge whether there are hidden and subtle defects such as jammed transmission mechanisms, insufficient contact finger clamping force, and incomplete closing and opening in the disconnector by measuring the changes in the corresponding characteristic quantities during the operation process of the disconnector, which play an important role in the mechanical fault diagnosis of disconnectors.

[0003] The existing mechanical fault diagnosis methods for disconnectors based on characteristic quantities such as motor current, torque, and rotation angle mainly have the following problems: First, due to the differences in the operating mechanisms and conductive arm structures, there are significant differences in the change characteristics of the motor current, torque, and rotation angle of disconnectors of different structural types. For example, the variation law of torque with the action stroke of double-column horizontal rotary and vertical telescopic disconnectors is completely different; Second, most of the existing diagnostic methods rely on longitudinal comparisons in different states of the disconnector (such as normal, jammed, or three-phase non-synchronous, etc.) or transverse comparisons between different phases of disconnectors in the same group, resulting in the effective implementation of the diagnostic method depending on a large number of characteristic curves of disconnectors of different types. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a mechanical fault diagnosis method for disconnectors that fuses multi-information parameters, uses curve coefficients to quantitatively describe the change laws of curves such as motor current, torque, and rotation angle, realizes the mechanical state assessment of disconnectors based on curve coefficients, can be applied to the mechanical states of disconnectors of different structural types, and effectively replaces the horizontal comparison method and longitudinal comparison method in traditional diagnostic methods.

[0005] To achieve the purpose of this invention, the present invention adopts the following technical solutions, including the following steps:

[0006] S1: Install an electrodynamic torque sensor (or manual torque sensor) at the manual handle operation position of the disconnector operating mechanism box, install a Hall current sensor in the control circuit of the driving motor, and install a rotation angle sensor at a suitable position on the transmission component connected between the disconnector operating mechanism box and the conductive arm. After installation, operate the disconnector through the operating mechanism box, and combine with the data acquisition device to measure and record the torque, current, and rotation angle changes during a single operation process (one opening or closing) of the disconnector;

[0007] S2: According to the measurement results of the torque sensor and the rotation angle sensor, plot the torque-time curve or torque-rotation angle curve, and record the maximum torque value F max during a single operation process (opening or closing), and solve the average value F avg and the effective value F rms of the torque during a single operation process. The calculation methods are as follows:

[0008]

[0009]

[0010] In the formula, T is the time period of a single measurement, and f(t) is the torque measurement value corresponding to the moment t;

[0011] Similarly, according to the measurement results of the current sensor, plot the motor current envelope curve, and record the maximum motor current value I max during a single operation process, and solve the average value I avg and the effective value I rms of the motor current during a single operation process. The calculation methods are as follows:

[0012]

[0013]

[0014] In the formula, T is the time period of a single measurement, and i(t) is the current value corresponding to the moment t in the current envelope curve;

[0015] S3: Calculate the ratio of the maximum torque value F max (or the effective value F rms ) to the average value F avg , and define it as the curve coefficient K1 of the torque curve. The calculation method is as follows:

[0016]

[0017] Similarly, calculate the ratio of the maximum value (or effective value) of the motor current to the average value, and define it as the curve coefficient K2 of the current envelope curve;

[0018]

[0019] S4: According to the values of the curve coefficients K1 and K2, it can be determined whether the disconnector is operating normally or what kind of mechanical fault exists. If the curve coefficients K1 and K2 meet the threshold setting requirements, the operating state of the disconnector is normal; if the curve coefficients K1 and K2 do not meet the threshold setting requirements, it is judged whether there are defects or faults such as out-of-synchronization or jamming in three-phase closing according to their numerical distribution intervals.

[0020] Taking the calculation of the curve coefficient by the ratio of the maximum value to the average value as an example, if K1 is greater than 1.5 and K2 is greater than 1.1, it indicates that the operating state of the disconnector is normal; if K1 is between 1.35 and 1.45 and K2 is less than 1.1, it indicates that the disconnector may have a three-phase out-of-synchronization fault; if K1 is less than 1.35 and K2 is less than 1.02, it indicates that the disconnector may have a jamming fault.

[0021] Further, the torque sensor in S1 should meet the following requirements: the sampling frequency is not less than 100 Hz, and the range is ±10 Nm; the Hall current sensor should meet the following requirements: the sampling frequency is not less than 1 kHz, and the range is 0 - 5 A; the rotation angle sensor should meet the following requirements: the sampling frequency is not less than 100 Hz, and the range is ±180°.

[0022] Further, for the calculation of the curve coefficients K1 and K2 in S3, if there are no obvious abnormal changes in the torque-time curve and the current envelope curve, the curve coefficient is calculated by the ratio of the maximum value to the average value; if there are local data anomalies caused by measurement, the curve coefficient is calculated by the ratio of the effective value to the average value.

[0023] Further, in S3, when there are local data anomalies in the single measurement result, the repeatability of the measurement result can be verified through multiple measurements, and the optimal measurement result is selected as the calculation input.

[0024] Further, in S3, if the curve coefficient is calculated using the effective value, the threshold value range of the curve coefficients K1 and K2 is reduced, and the data accuracy requirement is increased. The average value of multiple measurement results can be taken.

[0025] Advantages of the present invention:

[0026] A mechanical fault diagnosis method for a disconnector integrating multiple information parameters provided by the present invention can achieve the purpose of unifying the mechanical fault diagnosis basis for disconnectors of different structural types, replacing the longitudinal and transverse comparison methods used in traditional fault diagnosis methods, and overcoming the problem that the diagnosis method requires a large amount of collection of the change curves of the corresponding characteristic quantities of the disconnector in the normal operating state or the fault operating state and constructing a fault characteristic library for disconnectors of different structural types. Description of the Drawings

[0027] AppendixFigure 1 is the flow chart of the disconnector mechanical fault diagnosis method for multi-information parameter fusion described in the present invention;

[0028] Appendix Figure 2 is the schematic diagram of the disconnector structure in the embodiment of the present invention;

[0029] Appendix Figure 3 is the schematic diagram of the electrodynamic torque measurement of the disconnector in the embodiment of the present invention;

[0030] Appendix Figure 4 is the comparison diagram of the torque-rotation angle curves of the disconnector under normal state and jamming state in the embodiment of the present invention;

[0031] Appendix Figure 5 is the comparison diagram of the motor current envelope curves of the disconnector under normal state and jamming state in the embodiment of the present invention.

[0032] Illustration: 1. Installation bracket; 2. Base; 3. Operating rod; 4. Bearing; 5. Post insulator; 6. Conductive arm seat; 7. Conductive arm; 8. Contact seat; 9. Contact; 10. Phase-interphase connecting rod; 11. Inter-pole connecting rod; 12. Finger seat; 13. Finger; 14. Spring piece; 15. Operating mechanism box; 16. Operating rod crank arm; 17. Operating connecting rod; 18. Wiring busbar. Specific implementation manner

[0033] The following further describes the present invention in combination with embodiments. It is necessary to point out here that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art according to the above invention content still fall within the protection scope of the present invention.

[0034] Taking the mechanical fault diagnosis of the GW4-126 type high-voltage disconnector installed on the laboratory test platform as an example, the feasibility of the diagnosis method is determined in combination with the method of the present invention, and its diagnostic effect is verified and checked. Its flow chart is as Figure 1 shown. It includes the following steps:

[0035] S1: For the GW4-126 type disconnector installed on the laboratory test platform, its structure is as shown in Appendix Figure 2As shown. Among them, the group components include: mounting bracket 1, base 2, operating rod 3, bearing 4, post insulator 5, conducting arm seat 6, conducting arm 7, contact seat 8, contact 9, interphase connecting rod 10, inter-pole connecting rod 11, finger seat 12, finger 13, spring piece 14, operating mechanism box 15, operating rod crank arm 16, operating connecting rod 17, connecting busbar 18. An electric torque sensor (or manual torque sensor) is installed at the manual handle operation position of the operating mechanism box, a Hall current sensor is installed in the control circuit of the driving motor inside the operating mechanism box, and an angle sensor is installed at a suitable position on the transmission component connecting the disconnector operating mechanism box and the conducting arm. After installation, the disconnector is controlled to act through the operating mechanism box, and the data acquisition device is used to measure and record the torque, current, and angle change conditions during a single action process (one opening or closing) of the disconnector; the measurement of the electric torque of the disconnector is as Figure 3 shown.

[0036] S2: When the mechanical state of the disconnector is normal, according to the measurement results of the torque sensor and the angle sensor, a torque-angle curve is drawn, as Figure 4 shown by the bottommost curve. Record the maximum torque F max during a single action process (opening or closing) as 2.96 N·m, and solve for the average torque F avg during a single action process as 1.78 N·m, and the effective value F rms as 2.09 N·m. The calculation method is as follows:

[0037]

[0038]

[0039] In the formula, T is the time period of one measurement, and f(t) is the torque measurement value corresponding to the moment t;

[0040] Similarly, according to the measurement results of the current sensor, an envelope curve of the motor current is drawn, as Figure 5 shown by the topmost curve. Record the maximum motor current I max during a single action process as 0.80 A, and solve for the average motor current I avg during a single action process as 0.70 A, and the effective value I rms as 0.73 A. The calculation method is as follows:

[0041]

[0042]

[0043] In the formula, T is the time period of one measurement, and i(t) is the current value corresponding to the moment t in the current envelope curve;

[0044] S3: Calculate the maximum moment F max (or the effective value F rms ) and the average value F avg The ratio of them is defined as the curve coefficient K1 of the moment curve, and the calculation method is as follows:

[0045]

[0046] Similarly, calculate the ratio of the maximum value (or effective value) of the motor current to the average value, and define it as the curve coefficient K2 of the current envelope;

[0047]

[0048] The calculated curve coefficients K1 and K2 are 1.66 and 1.14 respectively.

[0049] S4: According to the values of the curve coefficients K1 and K2, it can be judged whether the disconnector is operating normally or what kind of mechanical faults exist. If the curve coefficients K1 and K2 meet the threshold setting requirements, the operating state of the disconnector is normal; if the curve coefficients K1 and K2 do not meet the threshold setting requirements, judge whether there are defects or faults such as out-of-synchronization or jamming in three-phase closing according to their numerical distribution intervals.

[0050] Taking the calculation of the curve coefficient by the ratio of the maximum value to the average value as an example, if K1 is greater than 1.5 and K2 is greater than 1.1, it indicates that the operating state of the disconnector is normal; if K1 is between 1.35 and 1.45 and K2 is less than 1.1, it indicates that the disconnector may have a three-phase out-of-synchronization fault; if K1 is less than 1.35 and K2 is less than 1.02, it indicates that the disconnector may have a jamming fault.

[0051] According to the above calculation results, it can be determined that the disconnector is in a normal state, verifying that this diagnostic method is feasible for the GW4-126 type disconnector.

[0052] Similarly, by artificially creating a jamming defect on the drive rod and repeating the above step S1, the following can be obtained Figure 4 The upper two moment-angle curves in the jamming state and Figure 5 The lower two current envelopes in the jamming state. Repeating the above steps S2 and S3, the curve coefficients K1 and K2 can be calculated to be 1.21 and 0.98 respectively, and according to their value ranges, it can be verified that there is indeed a jamming defect.

Claims

1. A mechanical fault diagnosis method for disconnectors with multi-information parameter fusion, characterized in that: It includes the following steps: S1: By installing an electric torque sensor or a manual torque sensor and a Hall current sensor in the disconnector operating mechanism box, and installing an angle sensor on the disconnector transmission component, and combining with a data acquisition device to measure and record the torque, current and angle change conditions during a single operation process of the disconnector; S2: According to the measurement results of the torque sensor and the angle sensor, draw a torque-time curve or a torque-angle curve, record the maximum torque value during a single operation process, and solve the average value and effective value of the torque during a single operation process; According to the measurement results of the current sensor, draw a motor current envelope, record the maximum motor current value during a single operation process, and solve the average value and effective value of the motor current during a single operation process; S3: Calculate the ratio of the maximum or effective value of the torque to the average value, and define it as the curve coefficient of the torque curve K 1; Calculate the ratio of the maximum or effective value of the motor current to the average value, and define it as the curve coefficient of the current envelope K 2; S4: According to the values of the curve coefficients K 1 and K 2, determine whether there is a mechanical fault in the disconnector; if the curve coefficients K 1 and K 2 meet the requirements, the operating state of the disconnector is normal; if Curve coefficient K 1 and K If 2 does not meet the requirements, it is judged whether there are defects or faults such as different closing times of three phases or jamming according to its numerical distribution range.

2. The mechanical fault diagnosis method for disconnector with multi-information parameter fusion according to claim 1, characterized in that: The torque sensor in S1 should meet the following requirements: the sampling frequency is not less than 100Hz, and the range is: ±10 Nm; the Hall current sensor should meet the following requirements: the sampling frequency is not less than 1kHz, and the range is: 0~5A; the angle sensor should meet the following requirements: the sampling frequency is not less than 100Hz, and the range is: ±180°.

3. The mechanical fault diagnosis method for disconnector with multi-information parameter fusion according to claim 1, characterized in that: The curve coefficients in S3 K 1 and K 2 are calculated as follows: If there are no obvious abnormal changes in the torque-time curve and the current envelope, the curve coefficient is calculated as the ratio of the maximum value to the average value; if there are local data abnormalities caused by measurement, the curve coefficient is calculated as the ratio of the effective value to the average value.

4. The mechanical fault diagnosis method for disconnector with multi-information parameter fusion according to claim 3, characterized in that: If there are local data anomalies in the single measurement results, the repeatability of the measurement results can be verified by multiple measurements, and the optimal measurement result is selected as the calculation input.

5. The mechanical fault diagnosis method for disconnector with multi-information parameter fusion according to claim 3, characterized in that: When calculating the curve coefficient using the effective value, the threshold value range of the curve coefficients K 1 and K 2 is reduced, and the data precision requirement is increased. The average value can be taken from multiple measurement results.

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