Device and method for measuring live working gap operation impulse discharge parameters

Abstract

The invention provides a live working gap operation impulse discharge parameter measuring device and method, and the device comprises an impulse voltage generator, a voltage divider, an oscilloscope, a high-voltage lead, and an optical fiber type current sensor which surrounds the periphery of the high-voltage lead. According to the device and the method, various hot-line work gaps can be simulated, the operation impact discharge physical parameters of the hot-line work gaps can be acquired, the anti-electromagnetic interference capability is relatively high, and powerful support can be provided for hot-line work research tests. The high-frequency signal detection device can accurately judge the discharge development time by capturing electromagnetic waves radiated by a streamer and pilot development system.

Description

Technical Field

[0001] The invention relates to the technical field of electrical engineering, and in particular to a device and method for measuring parameters of live working gap operation impulse discharge. Background Art

[0002] In UHV transmission lines, live working is generally used for operation and maintenance. In order to ensure the safety of live working personnel, the minimum safe distance for live working needs to be determined. Obtaining the characteristics of gap operation impulse discharge during live working is a prerequisite for determining the minimum safe distance. However, at present, there is a lack of detailed observation of the gap operation impulse discharge process during live working, and it is difficult to explain the influence mechanism of the posture of the operator and the characteristics of the line on the gap discharge characteristics. As a result, a large margin is often left when determining the safe distance, which to a certain extent causes a contradiction between the safety of live working and the economy of engineering construction. Therefore, by obtaining the physical parameters of gap operation impulse discharge during live working, it can provide strong support for practical engineering applications such as optimization of live working research and experiments and refined design of insulation coordination.

[0003] The gap for live working is a long air gap, but existing research mainly focuses on the rod-plate gap. The gap structure formed by workers, conductors and different poles and towers under live working conditions is quite different from the rod-plate long air gap structure. In addition, the electric field shielding caused by the proximity effect of the conductor makes the initiation and development process of the streamer leader in the live working gap different from that of the conventional gap. Therefore, the key parameters obtained in the existing long gap research are difficult to be directly used in the study of the discharge characteristics of the live working gap in actual engineering. At the same time, due to the complex gap structure formed by live working workers, poles and towers, and conductors, the measurement of various discharge parameters often has large errors. For example, the displacement current caused by stray capacitance is complex, which makes it difficult to accurately judge the characteristic starting current of the discharge current. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and provide a device and method for measuring parameters of live working gap operation impulse discharge, which can obtain physical parameters of live working gap operation impulse discharge.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a device for measuring parameters of live working gap operation impulse discharge, comprising: An impulse voltage generator is used to generate a positive polarity operating impulse voltage; A voltage divider connected to the impulse voltage generator; an oscilloscope connected to the voltage divider via a coaxial cable; High voltage lead, connecting the voltage divider with the simulator and the split wire; An optical fiber current sensor is surrounded by the high voltage lead; The high-frequency signal detection device includes two sets of high-frequency antennas and a host computer processor, which are arranged next to the high-speed camera. After the high-frequency antenna collects the discharge high-frequency signal, the host computer processor processes the characteristic signal in real time; A signal generator is connected to the oscilloscope, the high-speed camera and the current measuring device to achieve synchronous measurement of discharge voltage, discharge current and discharge development image of the gap during live working.

[0006] Furthermore, it also includes: A simulated tower window is grounded and hoisted to a height of 20 m above the ground, wherein the simulated person wears a full set of shielding clothing and is connected to the split conductor via a copper wire to achieve equipotentiality; The manikin and the split conductors are suspended on the simulated tower window using insulators, and the high-voltage electrode composed of the manikin and the split conductors forms a long air gap for live working with the simulated tower window.

[0007] Furthermore, the optical fiber current sensor includes an LED light source, and the light signal emitted by the LED light source is divided into two beams through a first coupler, one of which continues to be transmitted; the continuously transmitted light wave is converted into linearly polarized light after passing through a fiber polarizer, and the linearly polarized light is divided into two beams again after passing through a second coupler, and each beam of light passes through a fiber phase delay device and is converted into circularly polarized light. The two beams of circularly polarized light have the same rotation direction, and after passing through a third coupler, they enter the sensing fiber ring in opposite directions; the two beams of circularly polarized light propagate in the sensing fiber ring.

[0008] Furthermore, a method for measuring parameters of live working gap operation impulse discharge is implemented by using a live working gap operation impulse discharge parameter measuring device, and further includes: The velocity change of the two circularly polarized lights is manifested as a phase difference when they meet and interfere, specifically: ; in, is the phase difference; is the Faraday rotation angle, i.e. the angle at which light rotates under the action of a magnetic field; V is the Field constant, H is the magnetic field intensity, and l is the length of the sensing optical fiber; The magnetic field near a current-carrying conductor is: ; in, is the radius of the current-carrying conductor; The relationship between the phase difference and the current is: ; Wherein, N is the number of turns of the sensing optical fiber loop; I is the current value to be measured; When no current flows, the phase difference between the two light waves is zero, that is, , ; Fiber state function under the influence of current : ; The Faraday effect is related to the directionality of the current. The direction of the current will directly affect the sign of the measured phase difference. If the current is reversed, the sign of the phase difference should also be reversed accordingly. The change of phase difference with current direction is expressed as: ; Where S is a current directionality function defined. When the value is +1, it means that the current flows clockwise, and when the value is -1, it means that the current flows counterclockwise. A is the effective area of ​​the fiber ring. The Field constant V is affected by temperature T and external magnetic field B, so environmental correction needs to be considered: ; The phase difference changes with the environment: ; in, is the magnetic permeability of vacuum.

[0009] Furthermore, the birefringence effect in the optical fiber causes the two polarization components of the light to propagate at different speeds, which in turn affects the phase difference. Let the additional phase difference caused by birefringence be : ; in, is the total error after being affected only by birefringence; If the birefringence effect is not significant, that is: ; ; If there is a significant birefringence effect: ; in, is the fiber state function under the influence of birefringence effect.

[0010] Furthermore, when the optical fiber is subjected to external stress changes, the optical fiber material will be deformed, thereby affecting the measurement of the phase difference. The phase difference caused is: ; Where k is a constant related to the properties of the optical fiber material; is the stress-strain function; Assume that the stress-strain determination condition is: ; If significant stress-strain exists: ; in, is the fiber state function under the influence of stress and strain.

[0011] Furthermore, external electromagnetic interference will have an adverse effect on the measurement results of the optical fiber sensor. The interference function of the external electromagnetic field on the phase difference is for: .

[0012] Furthermore, the transmission intensity and phase difference of light are affected by the optical loss in the fiber ring. The effect of loss on the phase difference is expressed as: ; Where α is the loss coefficient; If the loss is not significant, then: ; Introduce the judgment conditions of optical loss: .

[0013] Further, determine whether the measurement is valid for: ; when The measurement is valid when , it indicates that the measurement will be affected by errors or environmental factors.

[0014] The beneficial effects of the present invention are as follows: the device includes a fiber optic current sensor, a current measuring device, a high-speed camera, a high-frequency signal detection device and a signal generator, and the discharge voltage signal measured by the voltage divider is transmitted to the oscilloscope via a cable. The fiber optic current sensor is wound around the high-voltage lead to measure the discharge current signal, which is transmitted to the current measuring device via the optical fiber; the high-speed camera is used to capture the optical image of the discharge process, and its working parameters are set according to the test layout, lens configuration, and resolution requirements; to ensure the consistency of electrical and optical observations in the test, the current measuring device and the high-speed camera are synchronized through the trigger signal output by the oscilloscope. The fiber optic current sensor is insensitive to electromagnetic interference and can accurately measure current in a strong electromagnetic environment; secondly, the optical fiber itself is an electrical insulator, which can avoid the influence of high voltage on the measuring equipment. In addition, the optical fiber has the characteristics of light weight and good flexibility, which is easy to install and maintain; Finally, the device and method can simulate various types of live working gaps and obtain the microscopic physical parameters of live working gap operation impulse discharge, and have strong anti-electromagnetic interference ability, which can provide strong support for live working research and experiments. The high-frequency signal detection device can accurately determine the time of discharge development from the ns level by capturing the electromagnetic waves radiated by the streamer and leader development system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a diagram of a device for measuring the parameters of live working gap operation impulse discharge; Figure 2 (a) Schematic diagram of the simulated person sitting with his back against the wire; Figure 2 (b) The mannequin is close to the conductor and facing away from the tower; Figure 3 Schematic diagram of a fiber optic current sensor. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] See also Figure 1 , a device for measuring parameters of live working gap operation impulse discharge, comprising: An impulse voltage generator 1, used for generating a positive polarity operating impulse voltage; A voltage divider 2 connected to the impulse voltage generator 1; an oscilloscope 9 connected to the voltage divider 2 via a coaxial cable 3; A high voltage lead 10, connecting the voltage divider 2 with the dummy 6 and the split wire 7; An optical fiber current sensor 11 is surrounded by the high voltage lead wire 10; The high-frequency signal detection device includes two sets of high-frequency antennas 15 and a host computer processor 16, which are arranged next to the high-speed camera 14. After the high-frequency antenna 15 collects the discharge high-frequency signal, the host computer processor 16 processes the characteristic signal in real time; The signal generator 13 is connected to the oscilloscope 9, the high-speed camera 14 and the current measuring device 8 to achieve synchronous measurement of the discharge voltage, discharge current and discharge development image of the live working gap.

[0018] After receiving the TTL signal from the oscilloscope 9 , the signal generator 13 sends signals to the high-speed camera 14 and the current measuring device 8 at the same time.

[0019] The current measuring device 8 is composed of a transmitter 26, a detector 25 and a signal processor 26. The transmitter 26 is connected to the LED light source 24, and the detector 25 is connected to the optical fiber current sensor 11 through an optical fiber. It is used to collect current signals and convert them into electrical signals for transmission to the signal processor 27. The signal processor 27 processes the current signals to obtain the corresponding discharge current waveform; the signal processor 27 is connected to the computer 28.

[0020] Also includes: See also Figure 2 (a) and Figure 2 (b), the simulated tower window 4 is grounded and hoisted to a height of 20 m above the ground, and the simulated person 6 wearing a full set of shielding clothing is connected to the split conductor 7 through copper wire to achieve equipotential; In a specific embodiment, insulators are used to hang the simulator 6 and the split conductor 7 on the simulated tower window 4. The high-voltage electrode composed of the simulator 6 and the split conductor 7 forms a long air gap for live working with the simulated tower window 4. The distance of the long air gap for live working is adjustable, and the posture of the simulator 6 can also be adjusted, so as to realize the construction of various typical live working conditions.

[0021] The manikin 6 and the split conductor 7 are suspended on the simulated tower window 4 using insulators 5 , and the high-voltage electrode composed of the manikin 6 and the split conductor 7 forms a long air gap with the simulated tower window 4 for live working.

[0022] The optical fiber current sensor 11 includes an LED light source 24, and the light signal emitted by the LED light source 24 is divided into two beams through the first coupler 191, one of which continues to be transmitted; the continuously transmitted light wave is converted into linearly polarized light after passing through the optical fiber polarizer 20, and the linearly polarized light is divided into two beams again after passing through the second coupler 192, and each beam of light passes through the optical fiber phase delay device 18 and is converted into circularly polarized light. The two beams of circularly polarized light have the same rotation direction, and after passing through the third coupler 193, they enter the sensing optical fiber ring 17 in opposite directions; the two beams of circularly polarized light propagate in the sensing optical fiber ring 17.

[0023] The working principle of a device for measuring the parameters of live working gap operation impulse discharge is as follows: Firstly, according to the test requirements, the simulator 6 is given a full set of shielding clothing, the required live working posture is adjusted, and the simulator 6 is connected to the split conductors through copper wires to form a high-voltage electrode. The horizontal distance between the high-voltage electrode and the side of the simulated tower window 4 is adjusted until the test requirements are met, thus simulating a long air gap working condition for live working to be tested.

[0024] The output voltage value of the impulse voltage generator is selected according to the step-up and step-down method until a discharge breakdown occurs in the long air gap of the live working. At this time, the discharge current will flow through the high-voltage lead. The optical fiber current sensor 11 wound around the high-voltage lead uses the Faraday magneto-optical effect to indirectly obtain the strength of the induced magnetic field surrounding the current, thereby realizing the collection of the discharge current.

[0025] The voltage divider 2 converts the high voltage signal generated by the impulse voltage generator into a low voltage signal, and transmits it to the oscilloscope 9 via a coaxial cable. The oscilloscope 9 outputs a TTL trigger signal after measuring the discharge voltage waveform.

[0026] After receiving the TTL trigger signal, the current measuring device 8 measures the discharge current waveform. After receiving the TTL trigger signal, the high-speed camera 14 records the discharge development image of the long air gap during live working. The high-speed camera is equipped with a lens with an aperture of 1.5 f and the shooting speed is set to 210 kfps.

[0027] The high-frequency antenna 15, the host computer processor 16 and the high-speed camera 14 are arranged in adjacent positions to record the distance between the high-frequency antenna and the typical discharge gap of live working, and the parameters of the two sets of antennas are set consistently; When the discharge develops, the streamer and the leader development system will radiate high-frequency signals, which are captured by the two sets of high-frequency antennas 15 respectively. Due to the position difference between the two sets of high-frequency antennas 15, two sets of signals with the same waveform and different time can be received. The signal can be detected with an accuracy of 0.1 ns. The high-frequency signals generated by the streamer and pilot discharge obtained in the experiment are mainly concentrated in tens to hundreds of kilohertz. By analyzing the characteristics of the two groups of real-time collected signals in the host computer processor 16, discharge signals of different frequencies can be distinguished and extracted.

[0028] The start time of the streamer and the leader can be accurately determined based on the measured high-frequency signal time difference, the heights of the two sets of high-frequency antennas 15, the distance between the typical discharge gap and the two sets of high-frequency antennas, and the discharge current waveform.

[0029] Combining the measured discharge voltage, discharge current and discharge development image, the characteristics of each stage of long air gap discharge development in live working can be verified from multiple angles, providing more detailed experimental information for the study of impact discharge characteristics of live working operations.

[0030] In the sensing fiber ring 17, the Faraday rotation angle caused by the current surrounding the magnetic field is ; A method for measuring parameters of gap operation impulse discharge during live working is implemented by a device for measuring parameters of gap operation impulse discharge during live working, and further comprises: The velocity change of the two circularly polarized lights is manifested as a phase difference when they meet and interfere, specifically: ; in, is the phase difference; is the Faraday rotation angle; is the Field constant, is the magnetic field strength, is the sensing optical fiber length; The magnetic field near a current-carrying conductor is: ; in, is the radius of the current-carrying conductor; The relationship between the phase difference and the current is: ; in, is the number of turns of the sensing optical fiber loop; is the current value to be measured; When no current flows, the phase difference between the two light waves is zero, that is, , ; Fiber state function under the influence of current : ; The Faraday effect is related to the directionality of the current. The direction of the current will directly affect the sign of the measured phase difference. If the current is reversed, the sign of the phase difference should also be reversed accordingly. The change of phase difference with current direction is expressed as: ; Where S is a current directionality function defined. When the value is +1, it means that the current flows clockwise, and when the value is -1, it means that the current flows counterclockwise. is the effective area of ​​the fiber ring; The Field constant V is affected by temperature T and external magnetic field B, so environmental correction needs to be considered: ; The phase difference changes with the environment: ; in, is the magnetic permeability of vacuum.

[0031] The birefringence effect in optical fiber causes the two polarization components of light to propagate at different speeds, which in turn affects the phase difference. Let the additional phase difference caused by birefringence be : ; in, is the total error after being affected only by birefringence; If the birefringence effect is not significant, that is: ; ; If there is a significant birefringence effect: ; in, is the fiber state function under the influence of birefringence effect.

[0032] When the optical fiber is subjected to external stress changes, it will cause the optical fiber material to deform, thus affecting the measurement of phase difference. The phase difference caused is: ; Where k is a constant related to the properties of the optical fiber material; is the stress-strain function; Assume that the stress-strain determination condition is: ; If significant stress-strain exists: ; in, is the fiber state function under the influence of stress and strain.

[0033] External electromagnetic interference will have an adverse effect on the measurement results of the optical fiber sensor. The interference function of the external electromagnetic field on the phase difference is for: .

[0034] The transmission intensity and phase difference of light are affected by the optical loss in the fiber ring. The effect of loss on the phase difference is expressed as: ; Where α is the loss coefficient; If the loss is not significant, then: ; Introduce the judgment conditions of optical loss: .

[0035] Further, determine whether the measurement is valid for: ; when The measurement is valid when , it indicates that the measurement will be affected by errors or environmental factors.

[0036] Fiber-optic current sensors are insensitive to electromagnetic interference and can accurately measure current in strong electromagnetic environments. Secondly, optical fiber itself is an electrical insulator, which can avoid the influence of high voltage on the measuring equipment. In addition, optical fiber is light in weight and flexible, making it easy to install and maintain.

[0037] It is necessary to consider reducing the errors caused by external environmental factors such as temperature and vibration. The fiber-optic current sensor is wrapped with insulation material to keep the phase error of the fiber-optic current sensor within 10 -6 rad, and the temperature change rate is less than 0.002 K / s.

[0038] Two groups of sensing fiber optic rings 17 are used as control data sampling under the same environment, one group is used to measure the current signal in the high-voltage lead, and the other group is placed in the same environment. Since the two groups of fiber optic rings will have the same reaction to temperature under the same environment, the signals collected by the two groups of sensing fiber optic rings 17 are differentiated to reduce the error caused by temperature.

[0039] The optical fiber sensing ring that measures current affects the offset when detecting current normally: ; in, is the offset caused only by the current; It is the offset caused by the influence of ambient temperature; The offset caused by the ambient temperature Thermal expansion coefficient of optical fiber material and thermo-optic coefficient The comparison sensor fiber ring is only affected by the environment, and the offset produced is The two groups of optical fibers use the same material and the same packaging, that is, , , when the two groups of optical fibers receive the same temperature When interference occurs, the offset .

[0040] In the actual acquisition process, the difference is obtained after differential temperature compensation As a fixed value, the calculated offset is less affected by temperature and the accuracy is greatly improved.

[0041] At the same time, a micro-optical linear polarizer attached with magneto-optical material is used to simultaneously collect temperature and Faraday rotation angle during the measurement process. The fiber-optic current sensor is illuminated by a broadband light source to analyze the original spectrum, thereby compensating for temperature fluctuations in current measurement.

[0042] A shock-absorbing package is used to suppress non-reciprocal errors caused by linear and angular vibrations.

[0043] The device and method can simulate various types of live working gaps and obtain the physical parameters of live working gap operation impact discharge, and have strong anti-electromagnetic interference ability and accuracy. The measured discharge current is less affected by the displacement current, and the judgment of the typical starting time of the discharge current is more accurate, which can provide strong support for live working research experiments.

[0044] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be based on the attached claims.

Claims

1. A device for measuring the parameters of live working gap operation impulse discharge, characterized in that: include: An impulse voltage generator (1) is used to generate a positive polarity operating impulse voltage; A voltage divider (2) connected to the impulse voltage generator (1); An oscilloscope (9) connected to the voltage divider (2) via a coaxial cable (3); A high voltage lead (10) connecting the voltage divider (2) with the simulator (6) and the split wire (7); An optical fiber current sensor (11) surrounding the high-voltage lead wire (10); A high-frequency signal detection device, comprising two sets of high-frequency antennas (15) and a host computer processor (16), arranged next to the high-speed camera (14); after the high-frequency antennas (15) collect the discharge high-frequency signal, the host computer processor (16) processes the characteristic signal in real time; A signal generator (13) is connected to the oscilloscope (9), the high-speed camera (14) and the current measuring device (8) to achieve synchronous measurement of the discharge voltage, discharge current and discharge development image of the gap during live working.

2. A device for measuring parameters of live working gap operation impulse discharge according to claim 1, characterized in that: Also includes: A simulated tower window (4) is grounded and hoisted to a height of 20 m above the ground, wherein the simulated person (6) wears a full set of shielding clothing and is connected to the split conductor (7) via a copper wire to achieve equipotentiality; The manikin (6) and the split conductor (7) are suspended on the simulated tower window (4) using insulators (5), and a high-voltage electrode formed by the manikin (6) and the split conductor (7) forms a long air gap for live working with the simulated tower window (4).

3. A device for measuring parameters of live working gap operation impulse discharge according to claim 2, characterized in that: The optical fiber current sensor (11) comprises an LED light source (24). The LED light source (24) emits an optical signal which is divided into two beams through a first coupler (191), one of which is continuously transmitted. The continuously transmitted light wave is converted into linearly polarized light after passing through an optical fiber polarizer (20). The linearly polarized light is again divided into two beams after passing through a second coupler (192). Each beam of light is converted into circularly polarized light after passing through an optical fiber phase delay device (18). The two beams of circularly polarized light have the same rotation direction and enter the sensing optical fiber ring (17) in opposite directions after passing through a third coupler (193). The two beams of circularly polarized light propagate in the sensing optical fiber ring (17).

4. A method for measuring the parameters of live working gap operation impulse discharge, characterized in that: The method is implemented by using a live working gap operation impulse discharge parameter measurement device as claimed in any one of claims 1 to 3, and further comprising: The velocity change of the two circularly polarized lights is manifested as a phase difference when they meet and interfere, specifically: ； in, is the phase difference; is the Faraday rotation angle, i.e. the angle at which light rotates under the action of a magnetic field; V is the Field constant, H is the magnetic field intensity, and l is the length of the sensing optical fiber; The magnetic field near a current-carrying conductor is: ； in, is the radius of the current-carrying conductor; The relationship between the phase difference and the current is: ； Wherein, N is the number of turns of the sensing optical fiber loop; I is the current value to be measured; When no current flows, the phase difference between the two light waves is zero, that is, , ; Fiber state function under the influence of current : ； The Faraday effect is related to the directionality of the current. The direction of the current will directly affect the sign of the measured phase difference. If the current is reversed, the sign of the phase difference should also be reversed accordingly. The change of phase difference with current direction is expressed as: ； Where S is a current directionality function defined. When the value is +1, it means that the current flows clockwise, and when the value is -1, it means that the current flows counterclockwise. A is the effective area of ​​the fiber ring. The Field constant V is affected by temperature T and external magnetic field B, so environmental correction needs to be considered: ； The phase difference changes with the environment: ； in, is the magnetic permeability of vacuum.

5. A method for measuring parameters of live working gap operation impulse discharge according to claim 4, characterized in that: The birefringence effect in optical fiber causes the two polarization components of light to propagate at different speeds, which in turn affects the phase difference. Let the additional phase difference caused by birefringence be : ； in, is the total error affected only by birefringence; If the birefringence effect is not significant, that is: ； ； If there is a significant birefringence effect: ； in, is the fiber state function under the influence of birefringence effect.

6. A method for measuring parameters of live working gap operation impulse discharge according to claim 5, characterized in that: When the optical fiber is subjected to external stress changes, it will cause the optical fiber material to deform, thus affecting the measurement of phase difference. The phase difference caused is: ； Where k is a constant related to the properties of the optical fiber material; is the stress-strain function; Assume that the stress-strain determination condition is: ; If significant stress-strain exists: ； in, is the fiber state function under the influence of stress and strain.

7. A method for measuring parameters of live working gap operation impulse discharge according to claim 6, characterized in that: External electromagnetic interference will have an adverse effect on the measurement results of the optical fiber sensor. The interference function of the external electromagnetic field on the phase difference is for: 。 8. A method for measuring parameters of live working gap operation impulse discharge according to claim 7, characterized in that: The transmission intensity and phase difference of light are affected by the optical loss in the fiber ring. The effect of loss on the phase difference is expressed as: ； Where α is the loss coefficient; If the loss is not significant, then: ； Introduce the judgment conditions of optical loss: 。 9. A method for measuring parameters of live working gap operation impulse discharge according to claim 8, characterized in that: Determine whether the measurement is valid for: ； when The measurement is valid when , it indicates that the measurement will be affected by errors or environmental factors.

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