Optical switch multi-channel system for partial discharge ultrasonic signal monitoring
By combining fiber optic grating sensors and optical switch arrays, the problems of low sensitivity and channel limitation in traditional partial discharge detection are solved, enabling efficient and non-invasive multi-channel monitoring of multiple power devices.
Patent Information
- Application Number
- CN202511194504.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-25
- Publication Date
- 2025-11-07
AI Technical Summary
Traditional partial discharge detection methods have low sensitivity, and the external acquisition channels of optical monitoring equipment are limited, making it difficult to meet the needs of multi-channel monitoring.
By employing fiber optic grating sensors and a 1×N optical switch array, and using a stepper motor to drive the fiber optic collimator switching, partial discharge signals of multiple power devices can be monitored. The optical switch array can be used to extend the monitoring data to multiple optical monitoring devices.
It achieves highly sensitive partial discharge detection for multiple power devices, breaking free from the channel limitations of existing optical monitoring equipment and possessing non-invasive, multi-channel monitoring capabilities.
Smart Images
Figure CN120908617A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of optical fiber sensing, and in particular to an optical switch multi-channel system for partial discharge ultrasonic signal monitoring. BACKGROUND
[0002] During the operation of electrical equipment, partial discharge often occurs due to uneven electric field distribution, aging of insulating materials, manufacturing process defects and other factors. Partial discharge not only reduces the insulation performance of the equipment, but also can even cause damage to the equipment and lead to safety accidents. Therefore, the detection of partial discharge of electrical equipment is particularly important.
[0003] Traditional partial discharge monitoring methods have their own limitations. The pulse current method is susceptible to coupling impedance and electromagnetic interference during detection, resulting in reduced monitoring sensitivity and signal-to-noise ratio, and must be detected with power off. The chemical analysis method determines the discharge state by analyzing the chemical gas generated by discharge, which has a lag.
[0004] The ultrasonic detection method based on optical fiber sensing technology, as a non-invasive detection method, has many advantages, such as no damage to the equipment, high sensitivity, remote detection, etc., and has gradually become one of the main means of partial discharge detection.
[0005] However, the current ordinary optical fiber sensor faces the problem of a large number of input monitoring targets and a large number of optical monitoring equipment requirements. Multi-channel optical fiber sensing monitoring equipment has a wide range of application scenarios. SUMMARY
[0006] The embodiment of the present application provides an optical switch multi-channel system for partial discharge ultrasonic signal monitoring, which is used to solve the problems of low sensitivity of traditional partial discharge detection technology, intrusion system, and the limitation of limited external collection channels of existing optical monitoring equipment.
[0007] To achieve the above purpose, the present application provides the following technical scheme:
[0008] The embodiment of the present application provides an optical switch multi-channel system for partial discharge ultrasonic signal monitoring, which comprises a fiber grating sensor, a 1xN optical switch array and a power equipment to be tested, the fiber grating sensor is connected to the 1xN optical switch array, the 1xN optical switch array is connected to the power equipment to be tested, and the switching between multiple power equipment to be tested through the 1xN optical switch array.
[0009] The 1xN optical switch array comprises a stepper motor and an input fiber array, the stepper motor drives a moving fiber collimator to move, and the moving fiber collimator is aligned with a static fiber collimator of the input fiber array, thereby completing the switching of the 1xN optical switch array.
[0010] The fiber grating sensor comprises a laser, a modulator, a circulator, a sensing fiber, a 3*3 coupler and a photodetector, the incident light generated by the laser becomes pulsed light through the acousto-optic modulator, the two reflected lights generated by the front and back two weak reflection gratings of the sensing fiber enter the 3*3 coupler for interference, the three output lights generated afterwards are accepted by the photodetector, the phase difference changes of the two reflected lights are obtained through correlation demodulation, and sensing measurement of the partial discharge signal is realized.
[0011] The sensing fiber is closely attached to the power equipment to be measured, and when the power equipment generates partial discharge, the generated vibration signal causes the axial strain change of the sensing fiber.
[0012] The sensing fiber is connected to the input fiber array.
[0013] Compared with the prior art, the beneficial effects of the present application are that when the power equipment generates partial discharge, the length changes due to the photoelastic effect of the fiber, the reflected light intensity of the weak reflection grating changes, and the partial discharge of the power equipment is detected by detecting the change of the light intensity. The switching of the power equipment to be measured can be realized through the optical switch.
[0014] Through the optical switch array, the monitoring data of the monitoring target input is expanded into multiple outputs to multiple optical monitoring devices, and the limitation of the limited external collection channel of the existing optical monitoring device is overcome. DETAILED DESCRIPTION
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.
[0016] Figure 1 A principle schematic diagram of an optical switch multi-channel system for monitoring partial discharge ultrasonic signals is provided in the present application.
[0017] Figure 2 A schematic diagram of a fiber sensor structure is provided.
[0018] Figure 3 A schematic diagram of the structure of the optical switch is provided. DETAILED DESCRIPTION
[0019] The technical solutions in the embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.
[0020] The terms "comprise", "comprising", or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.
[0021] The terms "first", "second", etc. are only used to distinguish one entity or operation from another entity or operation, and cannot be understood as indicating or implying relative importance, nor can they be understood as requiring or implying any such actual relationship or order between the entities or operations.
[0022] A light switch multi-channel system for partial discharge ultrasonic signal monitoring, the incident light generated by the laser becomes pulsed light through the acousto-optic modulator, and the two reflected lights generated by the front and rear two weak reflection gratings enter the 3*3 coupler for interference, and the three output lights generated are accepted by the photodetector, and the phase difference change of the two reflected lights is obtained through correlation demodulation, realizing the sensing measurement of the partial discharge signal.
[0023] Priority, when the partial discharge occurs in the power equipment to be measured, the generated acoustic vibration signal will cause the axial strain change of the sensing optical fiber attached to it. The phase information of the incident light through the sensing optical fiber will also change.
[0024] Priority, the phase difference change between the two reflected light beams formed by the two weak reflection gratings on the sensing optical fiber is linearly proportional to the axial strain change of the sensing optical fiber. The information of the partial discharge signal can be obtained by detecting the phase difference change.
[0025] Priority, the two reflected light beams formed by the two weak reflection gratings on the sensing optical fiber enter the 3*3 coupler for interference, forming three output light signals. The three output light signals contain phase information representing acoustic signals. The three output light signals have a phase difference of 120° between each other. Based on this mathematical feature, the phase difference change of the two reflected lights can be demodulated, and thus the partial discharge acoustic signal is obtained.
[0026] Priority, the 1*N optical switch can switch the sensing system on N power equipment to be measured, widening the number of monitoring channels of the sensing system.
[0027] As shown in Figure 1 Fiber grating sensor 1, 1*N optical switch 2, power equipment to be measured 3. As shown in Figure 3As shown, stepper motor 10, fiber array 11. Switching between multiple power equipment to be tested can be realized by 1xN optical switch, and the fiber grating sensing system can realize detection of multiple power equipment to be tested with limited photodetector, thus getting rid of the limitation of limited external acquisition channel of existing optical monitoring equipment.
[0028] As shown, laser 4, modulator 5, circulator 6, weak reflection fiber grating 7, 3x3 coupler 8, photodetector 9. Figure 2
[0029] The sensing fiber is closely attached to the power equipment to be tested, and when the power equipment has partial discharge, the generated vibration signal will cause the axial strain change of the sensing fiber. When the pressure generated by the external acoustic emission signal is F, the change amount of the light phase caused thereby can be represented as:
[0030]
[0031] The phase change in the fiber and the pressure generated by the acoustic emission signal are in linear relationship, and the external acoustic emission signal can be restored by demodulating the phase in the fiber.
[0032] The reflected light of the two weak reflection gratings on the sensing fiber enters the 3x3 coupler for interference, and the 3 output light signals have a phase difference of 120° between them.
[0033]
[0034] The 3 output light signals enter the photodetector to be converted into electrical signals, which are input to the PC end, and the correlation operation is performed on the 3 output signals, so that the phase difference between the reflected light of the two weak reflection gratings can be obtained , so that the external partial discharge acoustic signal can be restored.
[0035]
[0036] The acoustic signal can be demodulated by solving the arctangent function.
[0037] The above only describes the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. An optical switch multi-channel system for partial discharge ultrasonic signal monitoring, characterized in that, The application relates to a sensor for detecting partial discharge of power equipment, which comprises a fiber grating sensor, a 1*N optical switch array and power equipment to be detected, wherein the fiber grating sensor is connected to the 1*N optical switch array, the 1*N optical switch array is connected to sensing optical fibers on the power equipment to be detected, and the 1*N optical switch array is used for switching among the multiple power equipment to be detected.
2. An optical switch multi-channel system for partial discharge ultrasonic signal monitoring according to claim 1, characterized in that, The 1*N optical switch array comprises a stepping motor and an input optical fiber array, the stepping motor drives a moving optical fiber collimator to move, the moving optical fiber collimator is aligned with a static optical fiber collimator of the input optical fiber array, and thus the switching of the 1*N optical switch array is completed.
3. An optical switch multi-channel system for partial discharge ultrasonic signal monitoring according to claim 2, characterized in that, The fiber grating sensor comprises a laser, a modulator, a ring, a sensing optical fiber, a 3*3 coupler and a photodetector, incident light generated by the laser is changed into pulsed light through an acousto-optic modulator, two reflected lights generated by two weak reflection gratings before and after the sensing optical fiber enter the 3*3 coupler to interfere, three output lights generated after the 3*3 coupler are accepted by the photodetector, the change of phase difference of the two reflected lights is obtained through relevant demodulation, and sensing measurement of partial discharge signals is realized.
4. An optical switch multi-channel system for partial discharge ultrasonic signal monitoring according to claim 3, characterized in that, The sensing optical fiber is closely attached to the power equipment to be detected, when partial discharge occurs in the power equipment, vibration signals generated by the partial discharge can cause axial strain change of the sensing optical fiber.
5. An optical switch multi-channel system for partial discharge ultrasonic signal monitoring according to claim 4, characterized in that, The sensing optical fiber is connected to the 1*N optical switch array.