A Fault Location Method for Equal Gradient Traveling Wave Accelerator Tubes Based on Transmission Line Transient Response

Abstract

This invention discloses a fault location method for an equal-gradient traveling-wave accelerator tube based on transmission line transient response, belonging to the field of radio frequency electronic linear acceleration. It includes: equating the equal-gradient accelerator tube to a single transmission line composed of multiple cascaded uniform lossless transmission lines; and using transmission line transient response analysis methods to equate the transmission and reflection isowave processes of the delayed pulse generated by the traveling-wave pulse source in the transmission line to the transmission and reflection isowave processes at the moment of arcing fault occurrence in the equal-gradient traveling-wave accelerator tube. This yields the relationship between the round-trip time of the microwave pulse leading edge between the start and fault points and the fault location, thereby determining the fault location. This method can obtain the arcing location within the equal-gradient traveling-wave accelerator tube conveniently and at a relatively low cost without altering the existing accelerator device.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency electronic linear acceleration, and more specifically, relates to a fault location method for equal gradient traveling wave accelerator tubes based on the transient response of transmission lines. Background Technology

[0002] Radio frequency (RF) linear accelerators are widely used in basic scientific research such as free-electron lasers, synchrotron radiation sources, and large particle colliders, as well as in industrial fields such as testing, chemical engineering, and medicine. The traveling-wave accelerator tube is the core component of the RF linear accelerator, determining the beam performance of the accelerator device.

[0003] From both civilian and commercial perspectives, there is a desire to reduce the size of accelerator systems and increase their output beam power, thereby saving costs. This requires traveling-wave tubes (TWTs) to generate high-gradient accelerating voltages and operate at high average power. However, due to factors such as conductor materials, manufacturing precision, and vacuum levels, arcing inevitably occurs in TWTs during the process of increasing accelerating voltage and average power. In severe cases, this can cause permanent damage to the accelerator tube, and even damage to the power source and microwave devices due to excessive reflected power. Current research results cannot yet rigorously define the physical nature of arcing in radio frequency accelerators, and related theoretical and experimental studies typically involve complex and expensive detection systems and technologies. For large-scale accelerator facilities already built, if the arcing is reversible and does not cause permanent damage to the facility, it is desirable to analyze and study the location and cause of arcing within the TWT at a lower cost without altering the existing structure of the facility.

[0004] For equal-gradient traveling-wave accelerator tubes, existing technologies require expensive detection devices and complex techniques to determine the arcing location within the tube, which is complicated and costly. Summary of the Invention

[0005] In view of the shortcomings of the existing technology and the need for improvement, the present invention provides a fault location method for equal gradient traveling wave accelerator tube based on the transient response of the transmission line. Its purpose is to obtain the arcing position in the equal gradient traveling wave accelerator tube at a relatively low cost and with relatively convenient means without changing the current status of the accelerator device.

[0006] To achieve the above objectives, according to one aspect of the present invention, a fault location method for an equal-gradient traveling-wave accelerator tube based on the transient response of a transmission line is provided, comprising a transmission line circuit construction step and a fault location step:

[0007] The transmission line circuit construction steps include:

[0008] Each accelerating cavity of the equal-gradient traveling wave accelerator tube is equivalent to a lossless sub-transmission line, and multiple sub-transmission lines are cascaded to form a complete transmission line; the length and wave velocity of each transmission line are the length and group velocity of the corresponding accelerating cavity, respectively.

[0009] The arcing fault in the acceleration tube is equivalent to a low-resistance or short-circuit fault in a complete transmission line, and the low-resistance or short-circuit fault is represented by the fault resistance.

[0010] A traveling wave pulse source is connected in series in the complete transmission line to generate traveling wave pulses to simulate microwave pulses in the accelerating tube; a time delay switch is connected in series with the fault resistor to record the time of fault occurrence; wherein, the time difference between the ignition start time in the accelerating tube and the leading edge of the microwave pulse is the closing time of the time delay switch.

[0011] A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit.

[0012] The fault location step includes: equating the transmission and reflection isowave process of the traveling wave pulse source generating a delayed pulse in the transmission line circuit to the transmission and reflection isowave process when an arcing fault occurs in the accelerating tube, obtaining the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location, and then determining the fault location.

[0013] Furthermore, using the equivalent piecewise linear plot method in the transmission line circuit, the relationship between the round-trip time of the microwave pulse leading edge between the start and the fault point and the fault location is obtained. The relationship is as follows:

[0014]

[0015] In the formula, N x L is the faulty cavity number. x For the Nth x The distance L between the beginning of the acceleration chamber and the specific fault location. c v is the length of each acceleration cavity segment. gi Let t be the group velocity within the i-th acceleration cavity. x This is the round-trip time of the microwave front between the starting point and the fault point.

[0016] Furthermore, the round-trip time t between the microwave leading edge and the fault point... x Obtained through the following method:

[0017] Forward and reverse microwave pulses are acquired using a directional coupler and detector tube pre-installed at the beginning of the equal-gradient traveling wave accelerator tube;

[0018] The time delay between the forward and reverse microwave pulses is measured, where the time delay is the round-trip time t between the microwave leading edge and the fault point. x.

[0019] Furthermore, the fault cavity number N x Obtained through the following methods:

[0020] Establish the time t from the initial measurement to the leading edge of the reflected pulse at the beginning of the i-th accelerating cavity. i The cavity number N of the i-th accelerating cavity i The relationship between the time of the leading edge of the reflected pulse at the beginning of the i-th accelerating cavity and the cavity number N is obtained. i A data table with a one-to-one correspondence between them;

[0021] Based on the round-trip time t between the microwave front and the fault point x The corresponding cavity number is found in the data table to obtain the faulty cavity number N. x .

[0022] Furthermore, the time t at which the initial end measures the leading edge of the reflected pulse at the beginning of the i-th accelerating cavity is measured. i The cavity number N of the i-th accelerating cavity i The relationship between them is:

[0023]

[0024] Among them, L c v is the length of each acceleration cavity segment. gi Let i be the group velocity within the acceleration cavity of segment i.

[0025] Furthermore, all cascaded sub-transmission lines are matched connections.

[0026] Furthermore, by ensuring that the wave impedances between multiple sub-transmission lines are equal, the cascaded sub-transmission lines are all matched connections.

[0027] According to a second aspect of the present invention, a fault location system for an equal-gradient traveling-wave accelerator tube based on the transient response of a transmission line is provided, comprising:

[0028] The first equivalent unit is used to convert each accelerating cavity of the equal-gradient traveling wave accelerating tube into a lossless sub-transmission line, and multiple sub-transmission lines are cascaded to form a complete transmission line; wherein, the length and wave velocity of each sub-transmission line are the length and group velocity of the corresponding accelerating cavity, respectively.

[0029] The second equivalent unit is used to equate the arcing fault in the acceleration tube to a low-resistance or short-circuit fault in a complete transmission line, and the low-resistance or short-circuit fault is represented by the fault resistance.

[0030] A traveling wave pulse source, connected in series in the complete transmission line, is used to generate traveling wave pulses to simulate microwave pulses in the accelerating tube;

[0031] A time delay switch, connected in series with the fault resistor, is used to record the time of the fault occurrence; wherein, the time difference between the ignition start time in the accelerating tube and the leading edge of the microwave pulse is the closing time of the time delay switch;

[0032] A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit.

[0033] The fault location unit is used to equate the transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line circuit to the transmission and reflection isowave process when an arcing fault occurs in the accelerating tube, and obtain the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location, thereby determining the fault location.

[0034] According to a third aspect of the invention, a computer-readable storage medium is provided having a computer program stored thereon, characterized in that, when the program is executed by a processor, it implements the fault location method as described in any one of the first aspects.

[0035] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0036] (1) The fault location method of this invention equates the equal-gradient accelerator tube to an integral transmission line composed of multiple cascaded uniform lossless transmission lines. Utilizing the transient response analysis method of transmission lines, the transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line is equated to the transmission and reflection isowave process at the moment of arcing fault occurrence in the equal-gradient traveling wave accelerator tube. This yields the relationship between the round-trip time of the microwave pulse leading edge between the start and fault points and the fault location, thereby determining the fault location. This equivalent method of the present invention eliminates the need to consider the radio frequency carrier signal in the measured pulse waveform; only the delay of the delayed pulse generated by the traveling wave pulse source needs to be measured, greatly simplifying the fault location method and possessing engineering practicality. Furthermore, this equivalent approach avoids altering the existing conditions of the accelerator device and eliminates the need for expensive detection devices, significantly reducing the cost of fault location.

[0037] (2) In the application of the formula for fault location, it is only necessary to rely on the directional coupler and detector tube that are usually pre-installed in the accelerator device. The microwave pulse waveform measured by the oscilloscope is combined with the design parameters of the accelerator tube to analyze and obtain the accurate fault location. It has the advantages of fast positioning speed, low cost and simple analysis process.

[0038] (3) In the positioning method of the present invention, the cascaded sub-transmission lines are all matched connections, which can avoid the problem of reflected waves generated at the interface of different transmission lines, interfering with the identification of reflected waves at the fault point, and affecting the measurement accuracy of the round-trip time between the microwave front and the fault point.

[0039] In summary, this invention, based on the transient response theory of transmission lines, provides an economical and convenient method for fault analysis and location of equal-gradient traveling-wave accelerator tubes by establishing an equivalent relationship between the transmission line and the equal-gradient traveling-wave accelerator tube. This method can obtain the arcing location inside the equal-gradient traveling-wave accelerator tube at a relatively low cost and with greater convenience without changing the existing status of the accelerator device. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a fault location method provided in an embodiment of the present invention.

[0041] Figure 2 A flowchart of a fault location method provided in an embodiment of the present invention.

[0042] Figure 3 The circuit diagram of the overall transmission line, which is equivalent to a traveling wave accelerator tube, is provided for the embodiments of the present invention.

[0043] Figure 4 The transmission and reflection isowave processes in an equal-gradient traveling-wave accelerator tube during an arcing fault, as provided in an embodiment of the present invention, are analyzed using a piecewise linear graph.

[0044] Figure 5 A schematic diagram of the forward microwave waveform at the beginning of the equivalent overall transmission line provided in an embodiment of the present invention.

[0045] Figure 6 This is a schematic diagram of the reverse microwave waveform at the beginning of the equivalent overall transmission line provided in an embodiment of the present invention.

[0046] Figure 7 The oscilloscope provides an example of the present invention to show the forward and reverse microwave waveforms at the beginning of an equal-gradient traveling-wave accelerating tube. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] In this invention, the terms "first," "second," etc., used in the invention and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0049] like Figure 1 and Figure 2 As shown, the fault location method for equal-gradient traveling-wave accelerating tubes based on transmission line transient response of the present invention mainly includes transmission line circuit construction steps and fault location steps:

[0050] The steps for constructing a transmission line circuit include:

[0051] Each accelerating cavity of the equal-gradient traveling-wave accelerator tube is equivalent to a uniform, lossless sub-transmission line. Multiple sub-transmission lines are cascaded to form a complete transmission line, and the cascaded sub-transmission lines are matched connections. The length of each sub-transmission line is the length of the corresponding cavity of the equal-gradient traveling-wave accelerator tube, and the wave velocity of each sub-transmission line is the group velocity of the corresponding cavity of the equal-gradient traveling-wave accelerator tube.

[0052] Arson faults in equal-gradient traveling-wave accelerator tubes are equivalent to low-resistance or short-circuit faults in a complete transmission line, represented by the fault resistor R. f This indicates a low-resistance or short-circuit fault;

[0053] A traveling wave pulse source is connected in series in the complete transmission line to generate traveling wave pulses to simulate microwave pulses in a uniformly gradient traveling wave accelerator tube. A delay switch and a fault resistor R are also present. f In series, it is set between the faulty sub-transmission line and the adjacent sub-transmission line to record the time of the fault occurrence; wherein, the time difference between the arcing start time in the equal gradient traveling wave accelerating tube and the microwave pulse leading edge in the equal gradient traveling wave accelerating tube is the delay switch closing time of the low impedance or short circuit fault in the complete transmission line.

[0054] A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit.

[0055] Fault location steps include:

[0056] The transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line circuit is equivalent to the transmission and reflection isowave process at the moment of arcing fault in the equal-gradient traveling wave accelerating tube. The relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location is obtained, and then the fault location is determined.

[0057] Specifically, in this embodiment, the relationship between the round-trip time of the microwave pulse leading edge between the start and the fault point and the fault location is obtained by using the equivalent broken line graph method:

[0058]

[0059] In the formula, N x L is the faulty cavity number. x For the Nth x The distance L between the beginning of the acceleration chamber (i.e., the start of the acceleration chamber segment) and the specific fault location. c v is the length of each acceleration cavity segment. gi Let t be the group velocity within the i-th acceleration cavity. x This is the round-trip time of the microwave front between the starting point and the fault point.

[0060] In the above formula, the round-trip time t between the microwave leading edge and the fault point is... x Obtained through the following methods:

[0061] Forward and reverse microwave pulses are acquired using a directional coupler and detector tube pre-installed at the beginning of the equal-gradient traveling wave accelerator tube;

[0062] The time delay between the forward and reverse microwave pulses, i.e., the round-trip time t between the microwave leading edge and the fault point, is measured using an oscilloscope. x .

[0063] It should be noted that while traveling wave transmission line circuits require analysis and identification of incident and reflected traveling wave pulses, in this invention, after using the equivalent broken line diagram in the traveling wave transmission line circuit to obtain the relationship between the round-trip time of the microwave pulse leading edge between the start and fault points and the fault location, the identification of the reverse microwave pulse leading edge directly utilizes the directional characteristic of the pre-set directional coupler of the equal-gradient traveling wave accelerator tube itself, without needing to consider whether there is overlap between the incident and reflected microwave pulses. In other words, this invention comprehensively utilizes the advantages of both traveling wave transmission line circuits and equal-gradient traveling wave accelerator tubes to obtain the location information of the arcing fault point.

[0064] In the above formula, the fault cavity number N x Obtained through the following methods:

[0065] Establish the time t from the initial measurement to the leading edge of the i-th accelerating cavity reflected pulse. i The cavity number N of the i-th accelerating cavity i The relationship between the time of the leading edge of the reflected pulse in the i-th accelerating cavity and the cavity number N is obtained. i A data table with a one-to-one correspondence between them;

[0066] The fault time, i.e., the round-trip time t between the microwave leading edge and the fault point, is obtained using the above method. x By looking up the data table, the faulty cavity number N was obtained. x ;

[0067] Among them, the time t from the start point to the leading edge of the i-th accelerating cavity reflected pulse is established. i The cavity number N of the i-th accelerating cavity i The relationship between them is as follows:

[0068]

[0069] The obtained fault cavity number N x And the round-trip time t between the microwave leading edge and the fault point. x Substituting the relationship between the round-trip time of the microwave pulse leading edge between the start and the fault location into the formula for the fault location, the Nth pulse can be calculated.x The precise fault location L of each fault cavity x .

[0070] The present invention will be further described below with reference to the specific accompanying drawings:

[0071] (1) First, the equal-gradient traveling-wave accelerator tube is equivalent to a whole transmission line composed of multiple segments of uniform lossless transmission lines. When constructing the equivalent relationship, each cavity in the equal-gradient traveling-wave accelerator tube is equivalent to a small segment of uniform lossless transmission line; the equal-gradient traveling-wave accelerator tube as a whole is equivalent to a whole transmission line composed of multiple cascaded sub-transmission lines; the length of each sub-transmission line is equivalent to the length of the corresponding cavity in the accelerator tube; the wave velocity of each sub-transmission line is equivalent to the group velocity of the corresponding cavity in the accelerator tube. Among them, the cascaded sub-transmission lines are all matched connections. In transmission line theory, when the impedance is mismatched, reflected waves will be generated at the interface of different transmission line sections, interfering with the identification of reflected waves at the fault point, affecting the measurement accuracy of the round-trip time between the microwave front and the fault point, and even making it impossible to measure t. x To accurately identify reflected waves, impedance matching of the transmission lines is necessary. Specifically, this is achieved by ensuring that the wave impedances of multiple sub-transmission lines are equal, thus ensuring that all cascaded sub-transmission lines are matched.

[0072] (2) Secondly, the arcing fault in the equal gradient traveling wave accelerating tube is equivalent to the low resistance or short circuit fault in the overall transmission line. The time difference between the arcing start time in the equal gradient traveling wave accelerating tube and the microwave pulse front edge is equivalent to the delay switch closing time of the low resistance or short circuit fault in the overall transmission line.

[0073] Through the above equivalents, the established traveling wave transmission line circuit is as follows: Figure 3 As shown, Figure 3 in, u s (t) is a pulse voltage source; R l A resistor is applied to achieve impedance matching at the starting end; i1(t) is the pulse current in the line; R f For fault resistor; Z c The wave impedance of the transmission line.

[0074] Among them, pulse voltage source u s (t) and R l The series connection forms a traveling wave pulse source to generate traveling wave pulses simulating microwave pulses in a uniformly gradient traveling wave accelerator tube; the wave impedance Z of the transmission line c All sub-transmission lines used for cascading are matched connections; fault resistor R f It is connected in series with a time delay switch between the faulty sub-transmission line and the adjacent sub-transmission line, and together they are equivalent to an arcing fault.

[0075] (3) Based on the established traveling wave transmission line circuit, the relationship between the round-trip time of the microwave leading edge between the start and the fault point and the fault location is obtained using the piecewise linear diagram of the traveling wave transmission line. Specifically, the transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line circuit is equivalent to the transmission and reflection isowave process at the moment of arcing fault occurrence in the equal-gradient traveling wave accelerating tube. The equivalent transmission and reflection isowave process at the moment of arcing fault occurrence in the equal-gradient traveling wave accelerating tube is as follows: Figure 4 As shown. Figure 4 In the diagram, the horizontal axis represents the longitudinal position on a transmission line of length l; the vertical axis represents the time axis at different longitudinal positions; x represents the location of the fault point; where, Figure 4 There are two incident waves. The upper incident wave is the incident wave that propagated at the initial moment, and the lower incident wave is the incident wave that propagated at the moment the fault occurred.

[0076] according to Figure 4 Based on the wave process shown, and combined with the time delay characteristics of the transmission line transient response, schematic diagrams of the forward and reverse microwave pulse waveforms measured at the beginning are drawn, as shown below. Figure 5 and Figure 6 As shown. Figure 5 and Figure 6 t in f ' is the time it takes for the leading edge of the reflected pulse to reach the beginning, t t t is the initial emission time at the trailing edge of the pulse. t ′ represents the time it takes for the trailing edge of the reflected pulse to reach the beginning.

[0077] Then, based on the identification of the microwave pulse waveform edges and combined with the wave process, a formula for analyzing fault location is obtained:

[0078]

[0079] In the formula, N x L is the faulty cavity number. x For the Nth x The distance L between the beginning of the acceleration chamber (i.e., the start of the acceleration chamber segment) and the specific fault location. c v is the length of each acceleration cavity segment. gi Let t be the group velocity within the i-th acceleration cavity. x This is the round-trip time of the microwave front between the starting point and the fault point.

[0080] In practice, based on the forward and reverse microwave pulse waveforms acquired by the directional coupler pre-installed at the beginning of the equal-gradient traveling wave accelerating tube, the round-trip time t of the microwave leading edge between the beginning and the fault point is obtained by measuring the time delay using an oscilloscope. x ;like Figure 7 The figure shows the microwave pulse waveform measured at the beginning of the accelerating tube. Figure 7The waveform corresponding to Acc+ with the number 2 is the forward microwave pulse, and the waveform corresponding to Acc- with the number 3 is the reverse microwave pulse.

[0081] Based on the accelerator tube design parameters, the data table corresponding to the round-trip time of the wave from the initial end of the entire accelerator tube to the front end of each accelerator tube is calculated sequentially. Given the fault time, the faulty cavity number can be determined by looking up the data table, and then the precise fault location L of the faulty cavity can be calculated using the above formula. x .

[0082] In this embodiment, based on the waveform data and the design parameters of the accelerating tube, the fault cavity number is 23. In this embodiment, the equal gradient traveling wave accelerating tube has a total of 84 cavities, and the length of each cavity segment is 34.99 mm. Finally, by substituting the corresponding parameters into the formula for analyzing the fault location, the specific location of the fault is found to be 14.99 mm from the beginning of cavity number 23.

[0083] The present invention also provides a fault location system for an equal-gradient traveling-wave accelerating tube based on the transient response of a transmission line, comprising:

[0084] The first equivalent unit is used to convert each accelerating cavity of the equal-gradient traveling wave accelerating tube into a lossless sub-transmission line, and multiple sub-transmission lines are cascaded to form a complete transmission line; wherein, the length and wave velocity of each sub-transmission line are the length and group velocity of the corresponding accelerating cavity, respectively.

[0085] The second equivalent unit is used to equate the arcing fault in the accelerating tube to a low-resistance or short-circuit fault in the complete transmission line, and the low-resistance or short-circuit fault is represented by the fault resistance.

[0086] A traveling wave pulse source, connected in series in a complete transmission line, is used to generate traveling wave pulses to simulate microwave pulses in an accelerating tube;

[0087] A time delay switch, connected in series with the fault resistor, is used to record the time when the fault occurs; the time difference between the start of the ignition in the accelerating tube and the leading edge of the microwave pulse is the closing time of the time delay switch.

[0088] A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit.

[0089] The fault location unit is used to equate the transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line circuit to the transmission and reflection isowave process when an arcing fault occurs in the accelerating tube, and obtain the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location, thereby determining the fault location.

[0090] Among them, the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location is obtained by using the equivalent broken line diagram method in the transmission line circuit. The relationship is consistent with the relationship in the above fault location method. For details, please refer to the above fault location method.

[0091] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the specific steps of the fault location method described above.

[0092] This invention equates an equal-gradient accelerator tube to a single transmission line composed of multiple cascaded uniform lossless transmission lines, with matched connections between the sub-transmission lines. By employing the piecewise linear plot method in transmission line transient response analysis, the transmission and reflection isowave processes of the delayed pulse generated by the traveling wave pulse source in the transmission line can be equated to the transmission and reflection isowave processes at the moment of arcing fault occurrence in the equal-gradient traveling wave accelerator tube. This allows for the determination of the relationship between the round-trip time of the microwave pulse leading edge between the start and fault points and the fault location, thus enabling fault location determination. This equivalent method eliminates the need to consider the RF carrier signal in the measured pulse waveform; only the delay of the modulated square wave (i.e., the delayed pulse generated by the traveling wave pulse source) needs to be measured, significantly simplifying the problem and making it practical for engineering applications. Furthermore, this equivalent approach avoids altering the existing conditions of the accelerator device and eliminates the need for expensive detection devices, greatly reducing the cost of fault location.

[0093] In the application of the fault location formula, it is only necessary to rely on the directional coupler and detector tube that are usually pre-installed in the accelerator device. The microwave pulse waveform measured by the oscilloscope is combined with the design parameters of the accelerator tube to analyze and obtain the accurate fault location. It has the advantages of fast positioning speed, low cost and simple analysis process.

[0094] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fault location method for an equal-gradient traveling-wave accelerating tube based on the transient response of a transmission line, characterized in that, This includes the transmission line circuit construction steps and fault location steps: The transmission line circuit construction steps include: Each accelerating cavity of the equal-gradient traveling wave accelerator tube is equivalent to a lossless sub-transmission line, and multiple sub-transmission lines are cascaded to form a complete transmission line; the length and wave velocity of each transmission line are the length and group velocity of the corresponding accelerating cavity, respectively. The arcing fault in the acceleration tube is equivalent to a low-resistance or short-circuit fault in a complete transmission line, and the low-resistance or short-circuit fault is represented by the fault resistance. A traveling wave pulse source is connected in series in the complete transmission line to generate traveling wave pulses to simulate microwave pulses in the accelerating tube; a time delay switch is connected in series with the fault resistor to record the time of fault occurrence; wherein, the time difference between the ignition start time in the accelerating tube and the leading edge of the microwave pulse is the closing time of the time delay switch. A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit. The fault location step includes: equating the transmission and reflection isowave process of the traveling wave pulse source generating a delayed pulse in the transmission line circuit to the transmission and reflection isowave process when an arcing fault occurs in the accelerating tube, obtaining the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location, and then determining the fault location.

2. The fault location method according to claim 1, characterized in that, The relationship between the round-trip time of the microwave pulse leading edge between the start and the fault point and the fault location is obtained by using the equivalent piecewise linear diagram method in the transmission line circuit. The relationship is as follows: In the formula, N x L is the faulty cavity number. x For the Nth x The distance L between the beginning of the acceleration chamber and the specific fault location. c v is the length of each acceleration cavity segment. gi Let t be the group velocity within the i-th acceleration cavity. x This is the round-trip time of the microwave front between the starting point and the fault point.

3. The fault location method according to claim 2, characterized in that, The round-trip time t between the microwave front and the fault point x Obtained through the following method: Forward and reverse microwave pulses are acquired using a directional coupler and detector tube pre-installed at the beginning of the equal-gradient traveling wave accelerator tube; The time delay between the forward and reverse microwave pulses is measured, where the time delay is the round-trip time t between the microwave leading edge and the fault point. x .

4. The fault location method according to claim 2, characterized in that, The fault cavity number N x Obtained through the following methods: Establish the time t from the initial measurement to the leading edge of the reflected pulse at the beginning of the i-th accelerating cavity. i The cavity number N of the i-th accelerating cavity i The relationship between the time of the leading edge of the reflected pulse at the beginning of the i-th accelerating cavity and the cavity number N is obtained. i A data table with a one-to-one correspondence between them; Based on the round-trip time t between the microwave front and the fault point x The corresponding cavity number is found in the data table to obtain the faulty cavity number N. x .

5. The fault location method according to claim 4, characterized in that, The time t from the beginning of the i-th acceleration cavity to the leading edge of the initial reflected pulse is measured. i The cavity number N of the i-th accelerating cavity i The relationship between them is: Among them, L c v is the length of each acceleration cavity segment. gi Let i be the group velocity within the acceleration cavity of segment i.

6. The fault location method according to claim 1, characterized in that, All cascaded sub-transmission lines are matched connections.

7. The fault location method according to claim 6, characterized in that, By ensuring that the wave impedances between multiple sub-transmission lines are equal, the cascaded sub-transmission lines are all matched connections.

8. A fault location system for an equal-gradient traveling-wave accelerator tube based on the transient response of a transmission line, characterized in that, include: The first equivalent unit is used to convert each accelerating cavity of the equal-gradient traveling wave accelerating tube into a lossless sub-transmission line, and multiple sub-transmission lines are cascaded to form a complete transmission line; wherein, the length and wave velocity of each sub-transmission line are the length and group velocity of the corresponding accelerating cavity, respectively. The second equivalent unit is used to equate the arcing fault in the acceleration tube to a low-resistance or short-circuit fault in a complete transmission line, and the low-resistance or short-circuit fault is represented by the fault resistance. A traveling wave pulse source, connected in series in the complete transmission line, is used to generate traveling wave pulses to simulate microwave pulses in the accelerating tube; A time delay switch, connected in series with the fault resistor, is used to record the time of the fault occurrence; wherein, the time difference between the ignition start time in the accelerating tube and the leading edge of the microwave pulse is the closing time of the time delay switch; A traveling wave pulse source, a time delay switch, a fault resistor, and a complete transmission line constitute a transmission line circuit. The fault location unit is used to equate the transmission and reflection isowave process of the delayed pulse generated by the traveling wave pulse source in the transmission line circuit to the transmission and reflection isowave process when an arcing fault occurs in the accelerating tube, and obtain the relationship between the round-trip time of the microwave pulse leading edge between the beginning and the fault point and the fault location, thereby determining the fault location.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the fault location method as described in any one of claims 1-7.

Images