Dielectric loss measuring device and method for evaluating service life of motor

Abstract

The embodiment of the invention provides a dielectric loss measuring device and method for motor life extension evaluation. The device comprises a current transformer which is used for accessing a motor stator winding loop and converting loop current into measurement information current; the shunt is used for shunting the measurement information current; the digital-to-analog converter is used for converting the shunted three-phase measurement information current analog signal into a digital signal; and the calculation module is used for calculating a direct current and an alternating current according to the digital signal of the three-phase measurement information current, and calculating a dielectric loss coefficient according to the direct current and the alternating current. According to the embodiment of the invention, the portable dielectric loss measuring device is provided, repeated dismounting and connection of a circuit are not needed, and dielectric loss coefficient measurement can be carried out only by connecting the current transformer of the device into a loop. The digital-to-analog converter integrated by the device is adopted, and a standard capacitor or a protective resistor does not need to be added, so that the interference on the measurement information current is avoided, and meanwhile, the safety is ensured.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of dielectric loss measurement for motor life extension evaluation, and specifically relate to a device and method for measuring dielectric loss for motor life extension evaluation. Background Art

[0002] The main purpose of electrical life extension assessment is to understand the current status of electrical equipment, predict its remaining life, and formulate appropriate maintenance, upgrade or modification plans accordingly to extend the service life of the equipment and improve its operating efficiency.

[0003] Under the influence of an electric field, charged particles within an insulating material migrate, generating a weak current (leakage current). This current heats the dielectric and causes energy loss. Furthermore, the dielectric also consumes energy during polarization, especially when the polarization process is slow (such as relaxation polarization or space charge polarization), which takes a long time to reach a stable state, further causing energy loss.

[0004] Dielectric loss is a key indicator for evaluating the electrical performance of insulation materials and a crucial component in assessing the lifespan of electrical equipment. In high-voltage and high-frequency devices, excessive dielectric loss can degrade overall performance and even cause thermal breakdown of the insulation. Therefore, accurately measuring and evaluating dielectric loss is crucial for optimizing material selection and application. Summary of the Invention

[0005] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a device and method for measuring dielectric loss for motor life extension assessment.

[0006] One aspect of the present disclosure provides a device for measuring dielectric loss for motor life extension evaluation, the device comprising:

[0007] Current transformer, used to connect to the motor stator winding loop and convert the loop current into measurement information current;

[0008] A shunt, used for shunting the measurement information current;

[0009] A digital-to-analog converter, used for converting the analog signals of the three-phase measurement information current after shunting into digital signals;

[0010] a calculation module, configured to calculate a direct current and an alternating current based on the digital signal of the three-phase measurement information current, and calculate a dielectric loss coefficient based on the direct current and the alternating current;

[0011] The current transformer, the shunt and the digital-to-analog converter are sequentially connected in series, and the calculation module is connected to the digital-to-analog converter.

[0012] Furthermore, the current transformer adopts a high-ratio and high-precision current transformer.

[0013] Furthermore, the calculation module is specifically used to perform Park transformation on the digital signal of the three-phase measurement information current to obtain direct current and alternating current.

[0014] Furthermore, the Parker transformation is shown as follows:

[0015] i d =(2 / 3)(i a +α 2 i b +αi c )

[0016] i q =(2 / 3)(i a +αi b +α 2 i c )

[0017] Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

[0018] Furthermore, the dielectric loss coefficient is calculated by the following formula:

[0019] tanδ=i q / i d

[0020] Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

[0021] Another aspect of the present disclosure provides a method for measuring dielectric loss in motor life extension evaluation, based on the above-mentioned dielectric loss measurement device for motor life extension evaluation, the method comprising:

[0022] Use a current transformer to access the motor stator winding loop and convert the loop current into measurement information current;

[0023] Use a shunt to shunt the measurement information current;

[0024] Convert the three-phase measurement information current analog signals after shunting into digital signals using a digital-to-analog converter;

[0025] A direct current and an alternating current are calculated based on the digital signal of the three-phase measurement information current, and a dielectric loss coefficient is calculated based on the direct current and the alternating current.

[0026] Furthermore, the current transformer adopts a high-ratio and high-precision current transformer.

[0027] Furthermore, the step of calculating the direct current and the alternating current based on the digital signal of the measured information current includes:

[0028] Perform Park transformation on the digital signal of the three-phase measurement information current to obtain DC current and AC current.

[0029] Furthermore, the Parker transformation is shown as follows:

[0030] i d =(2 / 3)(i a +α 2 i b +αi c )

[0031] i q =(2 / 3)(i a +αi b +α 2 i c )

[0032] Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

[0033] Furthermore, the dielectric loss coefficient is calculated by the following formula:

[0034] tanδ=i q / i d

[0035] Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

[0036] The disclosed embodiments provide a device and method for measuring dielectric loss for motor life extension assessment. This convenient device eliminates the need for repeated circuit disassembly and reassembly, requiring only the device's current transformer to be connected to the circuit for dielectric loss coefficient measurement. The device's integrated digital-to-analog converter eliminates the need for standard capacitors or protective resistors, thus preventing interference with the measured current and ensuring safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a structural schematic diagram of a dielectric loss measurement device for motor life extension evaluation according to an embodiment of the present disclosure;

[0038] Figure 2 The present invention is a flowchart of a method for measuring dielectric loss in motor life extension assessment according to another embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0040] In addition, the described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations or operations are not shown or described in detail to avoid blurring various aspects of the present disclosure.

[0041] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0042] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Thus, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of this disclosure. As used in this disclosure, the term "and / or" includes any one of the associated listed items and all combinations of one or more of them.

[0043] Those skilled in the art will understand that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present disclosure, and therefore cannot be used to limit the scope of protection of the present disclosure.

[0044] like Figure 1As shown, an embodiment of the present disclosure provides a dielectric loss measurement device 100 for motor life extension assessment, wherein the device 100 includes a current transformer 110, a shunt 120 and a digital-to-analog converter 130 connected in series, and a calculation module 140 connected to the digital-to-analog converter 130.

[0045] Specifically, the current transformer 110 is a high-ratio, high-precision current transformer, which is connected to the motor stator winding loop 200 to perform loop current ratio conversion and convert the loop current into a smaller measurement information current. The shunt 120 is used to shunt the measurement information current to obtain a three-phase measurement information current. The digital-to-analog converter 130 is used to perform analog-to-digital conversion and convert the shunt three-phase measurement information current analog signal into a digital signal (i a ,i b ,i c The calculation module 140 collects the digital signal (i ) of the three-phase measurement information current from the digital-to-analog converter 130. a ,i b ,i c ), perform Park transformation (PARK) on the digital signal of the three-phase measurement information current to ensure the accuracy and effectiveness of the transformation, and decompose the DC current i in the three-phase current d and the AC current i q , the specific formula is as follows:

[0046] i d =(2 / 3)(i a +α 2 i b +αi c )

[0047] i q =(2 / 3)(i a +αi b +α 2 i c )

[0048] Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

[0049] Then the calculation module 140 calculates the DC current i d and the alternating current i q Calculate the dielectric loss coefficient. The specific formula is as follows:

[0050] tanδ=i q / id

[0051] Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

[0052] The disclosed embodiments of a dielectric loss measurement device for motor life extension assessment provide a convenient dielectric loss measurement device that eliminates the need for repeated circuit disconnection and reconnection. Dielectric loss coefficient measurements can be performed simply by inserting the device's current transformer into the loop. The device integrates a digital-to-analog converter, eliminating the need for standard capacitors or protective resistors, thereby avoiding interference with the measured current and ensuring device safety.

[0053] like Figure 2 As shown, another embodiment of the present disclosure provides a method for measuring dielectric loss for motor life extension evaluation. Based on the dielectric loss measurement device for motor life extension evaluation described in the previous embodiment, the method includes:

[0054] Step S1: Use a current transformer to access the motor stator winding loop and convert the loop current into a measurement information current.

[0055] Specifically, refer to Figure 1 , the current transformer 110 in the dielectric loss measuring device 100 is connected to the motor stator winding loop 200 to perform a transformation ratio conversion of the loop current, thereby converting the loop current into a smaller measurement information current.

[0056] Step S2: Use a shunt to shunt the measurement information current.

[0057] Specifically, the shunt 120 in the dielectric loss measurement device 100 is used to shunt the measurement information current to obtain three-phase measurement information current.

[0058] Step S3: using a digital-to-analog converter to convert the shunted three-phase measurement information current analog signal into a digital signal.

[0059] Specifically, the digital-to-analog converter 130 in the dielectric loss measurement device 100 is used to convert the shunted three-phase measurement information current analog signal into a digital signal (i a ,i b ,i c ).

[0060] Step S4: Calculate the direct current and the alternating current according to the digital signal of the three-phase measurement information current, and calculate the dielectric loss coefficient according to the direct current and the alternating current.

[0061] Specifically, the calculation module 140 in the dielectric loss measurement device 100 collects the digital signal (i a ,i b ,i c ), perform Park transformation (PARK) on the digital signal of the three-phase measurement information current to ensure the accuracy and effectiveness of the transformation, and decompose the DC current i in the three-phase current d and the AC current i q , the specific formula is as follows:

[0062] i d =(2 / 3)(i a +α 2 i b +αi c )

[0063] i q =(2 / 3)(i a +αi b +α 2 i c )

[0064] Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

[0065] Then, according to the DC current i d and the alternating current i q Calculate the dielectric loss coefficient. The specific formula is as follows:

[0066] tanδ=i q / i d

[0067] Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

[0068] A method for measuring dielectric loss for motor life extension assessment, disclosed in this embodiment, utilizes a portable dielectric loss measurement device. This device eliminates the need for repeated circuit disassembly and reassembly; it simply requires the device's current transformer to be connected to the circuit for dielectric loss coefficient measurement. The use of a digital-to-analog converter eliminates the need for standard capacitors or protective resistors, thus preventing interference with the measured current and ensuring the safety of the method.

[0069] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A dielectric loss measurement device for motor life extension assessment, characterized in that: The device comprises: Current transformer, used to connect to the motor stator winding loop and convert the loop current into measurement information current; A shunt, used for shunting the measurement information current; A digital-to-analog converter, used for converting the analog signals of the three-phase measurement information current after shunting into digital signals; a calculation module, configured to calculate a direct current and an alternating current based on the digital signal of the three-phase measurement information current, and calculate a dielectric loss coefficient based on the direct current and the alternating current; The current transformer, the shunt and the digital-to-analog converter are sequentially connected in series, and the calculation module is connected to the digital-to-analog converter.

2. The device according to claim 1, characterized in that The current transformer adopts a high-transformation-ratio and high-precision current transformer.

3. The device according to claim 1, characterized in that The calculation module is specifically used to perform Park transformation on the digital signal of the three-phase measurement information current to obtain direct current and alternating current.

4. The device according to claim 3, characterized in that The Parker transform is shown below: i d =(2 / 3)(i a +α 2 i b +αi c ) i q =(2 / 3)(i a +αi b +α 2 i c ) Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

5. The device according to any one of claims 1 to 4, characterized in that The dielectric loss factor is calculated by the following formula: tanδ=i q / i d Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

6. A method for measuring dielectric loss for motor life extension evaluation, based on the dielectric loss measurement device for motor life extension evaluation according to any one of claims 1 to 5, characterized in that: The method comprises: Use a current transformer to access the motor stator winding loop and convert the loop current into measurement information current; Use a shunt to shunt the measurement information current; Convert the three-phase measurement information current analog signals after shunting into digital signals using a digital-to-analog converter; A direct current and an alternating current are calculated based on the digital signal of the three-phase measurement information current, and a dielectric loss coefficient is calculated based on the direct current and the alternating current.

7. The method according to claim 6, characterized in that The current transformer adopts a high-transformation-ratio and high-precision current transformer.

8. The method according to claim 6, characterized in that The step of calculating the direct current and the alternating current based on the digital signal of the measured information current includes: Perform Park transformation on the digital signal of the three-phase measurement information current to obtain DC current and AC current.

9. The method according to claim 8, characterized in that The Parker transform is shown below: i d =(2 / 3)(i a +α 2 i b +αi c ) i q =(2 / 3)(i a +αi b +α 2 i c ) Where i d is the DC current, i q is the alternating current, i a 、i b 、i c is the three-phase measurement information current, α=e (j2π / 3) is the complex number of a rotation of 120°.

10. The method according to any one of claims 6 to 9, characterized in that The dielectric loss factor is calculated by the following formula: tanδ=i q / i d Where tanδ is the dielectric loss coefficient, i d is the DC current, i q For alternating current.

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