Novel acoustooptic combined monitoring method and system for extra-high voltage large oil-filled equipment

Abstract

The application discloses a novel acousto-optic-electric combined monitoring method and system for extra-high voltage large oil-filled equipment, relates to the electrical equipment and measurement technical field, and comprises the following steps: acquiring discharge parameters of the extra-high voltage oil-filled equipment, wherein the discharge parameters comprise maximum amplitude, pulse number and phase width; if the parameters increase simultaneously, it indicates that the equipment may have a discharge fault; otherwise, it may be interference; if the discharge fault is detected, a sound sensor is used to determine the fault source; if the fault is internal discharge, the fault type is determined according to the discharge frequency; for the continuous discharge fault, the amplitude and pulse number growth rates are calculated, and the equipment maintenance state is evaluated according to the growth rates. Through the acousto-optic-electric combined diagnosis, the application can discover the fault earlier and more accurately and make a response, so that the reliability of the extra-high voltage large oil-filled equipment and the whole power system is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical equipment and measurement, in particular to a novel acoustic-optical-electric combined monitoring method and system for an extra-high voltage large oil-filled equipment. BACKGROUND

[0002] The extra-high voltage large oil-filled equipment is technically complex and costly to manufacture. Once an insulation fault occurs, it may cause serious accidents such as combustion and explosion, which not only endangers the safety of the equipment itself, but also leads to huge economic losses, and has a crucial impact on the safety and economy of the power system. To ensure the safe operation of these equipment, a monitoring method that can detect potential faults at an early stage, reduce false positives, and significantly improve the accuracy and reliability of monitoring is particularly important to provide strong protection for the safe and stable operation of the extra-high voltage power system.

[0003] The existing acoustic signal and electric signal monitoring means often face the problems of low confidence and insufficient effectiveness when detecting faults of the extra-high voltage large oil-filled equipment due to physical characteristics and environmental influences. Acoustic signal monitoring is easily disturbed by environmental noise, and the signal is prone to attenuation during transmission, resulting in a high risk of false positives and false negatives; electric signal monitoring is sensitive to electromagnetic interference, making it difficult to accurately capture equipment fault information and leading to frequent false positives, and it is difficult to provide reliable fault warnings. Optical signal monitoring, with its anti-interference ability of being unaffected by electromagnetic waves and environmental noise, has become a powerful supplement to acoustic and electric monitoring, providing more reliable protection for fault detection of extra-high voltage equipment. However, the existing measurement means in the current laboratory cannot effectively combine acoustic, electric and optical signals, and cannot fully utilize their respective advantages. SUMMARY

[0004] The purpose of the present application is to provide a novel acoustic-optical-electric combined monitoring method and system for an extra-high voltage large oil-filled equipment, which can detect faults earlier and more accurately through acoustic-optical-electric combined diagnosis.

[0005] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0006] In a first aspect, the present application provides a novel acoustic-optical-electric combined monitoring method for an extra-high voltage large oil-filled equipment, comprising:

[0007] Obtaining a discharge parameter of a composite signal of the extra-high voltage large oil-filled equipment within a unit time; the composite signal comprises an acoustic signal, an optical signal and an electric signal; the discharge parameter comprises a discharge frequency, a discharge amplitude and a phase of the composite signal.

[0008] According to the discharge parameter of the composite signal, calculating a maximum amplitude, a pulse number and a phase width of the composite signal; the pulse number is used to quantify the degree of increase in the discharge frequency.

[0009] If the values of the maximum amplitude, the pulse number and the phase width are simultaneously increased, it is determined that the ultrahigh voltage large oil-filled equipment has a discharge fault; otherwise, it is determined that the ultrahigh voltage large oil-filled equipment is interfered.

[0010] When the ultrahigh voltage large oil-filled equipment has a discharge fault, a source of the discharge signal is determined according to the sound sensor signal receiving time at each position of the ultrahigh voltage large oil-filled equipment, and the source of the discharge signal includes internal discharge and external discharge.

[0011] When the source of the discharge signal is internal discharge, a discharge fault type is determined according to the number of discharges per unit time, and the discharge fault type includes sharp / occasional discharge and continuous discharge fault.

[0012] When the discharge fault type is continuous discharge fault, an amplitude growth rate and a pulse number growth rate are calculated based on the maximum amplitude and the pulse number of the composite signal.

[0013] According to the amplitude growth rate and the pulse number growth rate, a maintenance state of the ultrahigh voltage large oil-filled equipment is determined based on a set threshold, and the maintenance state includes overhaul, alarm and tripping.

[0014] Optionally, calculating the maximum amplitude of the composite signal according to the discharge parameters of the composite signal specifically includes:

[0015] According to the discharge amplitude of the composite signal per unit time, the maximum amplitude of the composite signal is determined by using a peak value detection method.

[0016] Optionally, calculating the pulse number of the composite signal according to the discharge parameters of the composite signal specifically includes:

[0017] A power frequency cycle is equally divided into a plurality of phase windows.

[0018] For each phase window, the pulse number of the composite signal is calculated according to the number of discharges of the composite signal in the phase window.

[0019] Optionally, for each phase window, the pulse number of the composite signal is calculated according to the number of discharges of the composite signal in the phase window, specifically including:

[0020] The pulse number of the composite signal is calculated according to the formula

[0021] Wherein, M is the total number of detected power frequency cycles per unit time, n is is the number of discharges of the s-th cycle in the phase window , and N i is the pulse number.​​​

[0022] Optionally, the phase width of the composite signal is calculated according to the discharge parameter of the composite signal, specifically comprising:

[0023] The phase width of the composite signal is calculated according to the formula

[0024] Wherein, is the phase after a unit time is the phase at t=0 is the phase width, T is the power frequency period, and t is the time.

[0025] Optionally, when the discharge fault occurs in the UHV large oil-filled equipment, the source of the discharge signal is determined according to the receiving time of the acoustic sensor signal at each position of the UHV large oil-filled equipment, specifically comprising:

[0026] The receiving time t of the acoustic sensor signal at each position of the UHV large oil-filled equipment is obtained.

[0027] When t

[0028] When t> threshold T1, it is determined that the discharge signal occurs outside the equipment.

[0029] Optionally, when the source of the discharge signal is internal discharge, the type of the discharge fault is determined according to the number of discharges per unit time; the type of the discharge fault includes sharp / occasional discharge and continuous discharge fault, specifically comprising:

[0030] According to the number of pulses of the composite signal, when the number of pulses

[0031] When the number of pulses of the composite signal is greater than threshold N1, it is determined as a continuous discharge fault.

[0032] Optionally, when the type of the discharge fault is a continuous discharge fault, the amplitude growth rate and the pulse number growth rate are calculated based on the maximum amplitude and the number of pulses of the composite signal, specifically comprising:

[0033] The amplitude growth rate is calculated according to the formula

[0034] The pulse number growth rate is calculated according to the formula

[0035] Wherein, V0 is the signal amplitude at the initial time, N0 is the pulse number at the initial time, Δt is the interval time, V1 is the signal amplitude after the time Δt, and N1 is the pulse number after the time Δt.

[0036] ​​​The second aspect of the application provides a new type of photoacoustic combined monitoring system of an extra-high voltage large oil-filled equipment, comprising:

[0037] A parameter acquisition module is configured to acquire a discharge parameter of a composite signal of the extra-high voltage large oil-filled equipment within a unit time; the composite signal comprises an acoustic signal, an optical signal and an electrical signal; and the discharge parameter comprises a discharge frequency, a discharge amplitude and a phase of the composite signal.

[0038] A first calculation module is configured to calculate a maximum amplitude, a pulse number and a phase width of the composite signal according to the discharge parameter of the composite signal; and the pulse number is used to quantify a growth degree of the discharge frequency.

[0039] A fault judgment module is configured to judge whether the values of the maximum amplitude, the pulse number and the phase width within a set time simultaneously increase; if yes, it is judged that the extra-high voltage large oil-filled equipment has a discharge fault; and if no, it is judged that the extra-high voltage large oil-filled equipment is interfered.

[0040] A signal source judgment module is configured to judge a discharge signal source according to a receiving time of an acoustic sensor signal at each position of the extra-high voltage large oil-filled equipment when the extra-high voltage large oil-filled equipment has a discharge fault; and the discharge signal source comprises internal discharge and external discharge.

[0041] A fault type judgment module is configured to judge a discharge fault type according to the discharge frequency within a unit time when the discharge signal source is internal discharge; and the discharge fault type comprises a spike / occasional discharge and a continuous discharge fault.

[0042] A second calculation module is configured to calculate an amplitude growth rate and a pulse number growth rate based on the maximum amplitude and the pulse number of the composite signal when the discharge fault type is the continuous discharge fault.

[0043] A state maintenance module is configured to determine a maintenance state of the extra-high voltage large oil-filled equipment based on a set threshold value according to the amplitude growth rate and the pulse number growth rate; and the maintenance state comprises repair, alarm and tripping.

[0044] Optionally, the signal source judgment module specifically comprises:

[0045] A time acquisition submodule is configured to acquire a receiving time t of an acoustic sensor signal at each position of the extra-high voltage large oil-filled equipment.

[0046] A judgment submodule is configured to judge that a discharge signal comes from an internal part of the equipment when t is less than a threshold value T1, and judge that the discharge signal occurs outside the equipment when t is greater than the threshold value T1.

[0047] According to the specific embodiments provided in the application, the following technical effects are disclosed:

[0048] The application provides a novel acousto-optic-electric combined monitoring method and system for an extra-high voltage large oil-filled equipment, acquires a discharge parameter of a composite signal of the extra-high voltage large oil-filled equipment in a unit time; the composite signal covers an acoustic signal, an optical signal and an electric signal; the discharge parameter includes a discharge frequency, a discharge amplitude and a phase of the composite signal. According to the discharge parameter of the composite signal, a maximum amplitude, a pulse number and a phase width of the composite signal are calculated; the pulse number is used for quantifying a growth degree of the discharge frequency. Whether the values of the maximum amplitude, the pulse number and the phase width in a set time increase synchronously is judged; if yes, it is determined that the extra-high voltage large oil-filled equipment has a discharge fault; if not, it is determined that the extra-high voltage large oil-filled equipment is interfered. When the extra-high voltage large oil-filled equipment has a discharge fault, according to a signal receiving time of each position acoustic sensor, a source of a discharge signal is judged; the source of the discharge signal is divided into internal discharge and external discharge. When the source of the discharge signal is internal discharge, according to the discharge frequency in a unit time, a discharge fault type is judged; the discharge fault type includes a spike / occasional discharge and a continuous discharge fault. When the discharge fault type is the continuous discharge fault, based on the maximum amplitude and the pulse number of the composite signal, an amplitude growth rate and a pulse number growth rate are calculated. According to the amplitude growth rate and the pulse number growth rate, in combination with a set threshold, a maintenance state of the extra-high voltage large oil-filled equipment is determined; the maintenance state includes repair, alarm and tripping. The acousto-optic-electric combined monitoring method can synchronously acquire information of three different physical signals of sound, light and electricity, each signal corresponds to different fault characteristics. Through fusion analysis of multi-dimensional information, noise and interference in the acoustic and electric signals are effectively filtered out, the real state of the fault is more comprehensively reflected, the limitations of the acoustic and electric signal diagnosis method are avoided, and the accuracy of fault diagnosis is improved. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0050] Figure 1 A flowchart of a novel acousto-optic-electric combined monitoring method for an extra-high voltage large oil-filled equipment is provided for an embodiment of the present application.

[0051] Figure 2 A schematic diagram of a whole judgment mode of acousto-optic-electric combined monitoring is provided for an embodiment of the present application.

[0052] Figure 3 A specific judgment flowchart of acousto-optic-electric combined monitoring is provided for an embodiment of the present application.

[0053] Figure 4 This is a schematic diagram of a novel acoustic-optical-electrical combined monitoring system for a large-scale oil-filled ultra-high voltage power transmission equipment, provided as an embodiment of this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0055] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] Example 1

[0057] like Figure 1 As shown, this embodiment provides a novel acoustic-optical-electrical combined monitoring method for large-scale ultra-high voltage oil-filled equipment, including:

[0058] Step 101: Obtain the discharge parameters of the composite signal of the UHV large oil-filled equipment per unit time; the composite signal includes acoustic signal, optical signal and electrical signal; the discharge parameters include the number of discharges, discharge amplitude and the phase of the composite signal.

[0059] Step 102: Calculate the maximum amplitude, number of pulses, and phase width of the composite signal based on the discharge parameters of the composite signal; the number of pulses is used to quantify the degree of increase in the number of discharges.

[0060] Step 103: Determine whether the maximum amplitude, pulse count, and phase width increase simultaneously within a set time period; if yes, determine that the UHV large oil-filled equipment has a discharge fault; if no, determine that the UHV large oil-filled equipment is being interfered with.

[0061] Step 104: When the UHV large oil-filled equipment experiences a discharge fault, the source of the discharge signal is determined based on the signal reception time of the acoustic sensors at various locations of the UHV large oil-filled equipment; the source of the discharge signal includes internal discharge and external discharge.

[0062] Step 105: When the discharge signal originates from internal discharge, determine the discharge fault type based on the number of discharges per unit time; the discharge fault types include spike / intermittent discharge and continuous discharge fault.

[0063] Step 106: When the discharge fault type is a continuous discharge fault, calculate the amplitude growth rate and pulse number growth rate based on the maximum amplitude and pulse number of the composite signal.

[0064] Step 107: determining the maintenance state of the ultra-high voltage large oil-filled equipment based on the set threshold according to the amplitude growth rate and the pulse number growth rate; the maintenance state includes overhaul, alarm and tripping.

[0065] Specifically, as shown in FIG. 1, the present embodiment identifies discharge through acoustic, optical and electrical signals. Based on the basic local discharge signals, including maximum amplitude, pulse number per unit time, phase broadening degree, sound sensor signal receiving time at different positions, continuous discharge, amplitude growth rate and pulse number growth rate, whether the ultra-high voltage large oil-filled equipment has discharge fault, whether the fault position is internal or external, whether the discharge fault is continuously developing and whether it reaches the near breakdown state are monitored and judged, and corresponding overhaul signal, alarm signal or protection tripping signal is sent. Figure 2

[0066] In some embodiments, when step 101 is performed, the following steps can be specifically performed:

[0067] The discharge times N of the composite signal (acoustic, optical and electrical signals) of the ultra-high voltage large oil-filled equipment per unit time, the discharge amplitude V and the phase thereof are obtained.

[0068] In some embodiments, when step 102 is performed, the following steps can be specifically performed:

[0069] Step 201: determining the maximum amplitude of the composite signal by peak detection method according to the discharge amplitude of the composite signal per unit time.

[0070] Specifically, according to the discharge amplitudes V1, V2, …, V n , the maximum amplitude is V max = {V1, V2, …, V n}.

[0071] Step 202: dividing one power frequency cycle into a plurality of phase windows; for each phase window, calculating the pulse number of the composite signal according to the discharge times N i of the composite signal in the phase window. Specifically, the pulse number of the composite signal is calculated according to the formula

[0072] .

[0073] wherein M is the total number of detected power frequency cycles per unit time, n is is the discharge times of the s-th cycle in the phase window, and N i is the pulse number. ​​​

[0074] Step 203: calculating the phase width of the composite signal according to the discharge parameter of the composite signal, specifically comprising:

[0075] According to the formula The phase width of the composite signal is calculated.

[0076] Wherein, is the phase after unit time is the phase at t = 0 is the phase width, T is the power frequency period, and t is the time.

[0077] Wherein, in some embodiments, when steps 103-107 are performed, specifically as follows:

[0078] As Figure 3 shown, according to the calculated maximum amplitude, pulse number and phase width of the composite signal; the pulse number is used to quantify the degree of discharge frequency increase, to determine whether the values of maximum amplitude, pulse number and phase width in the set time increase simultaneously; if yes, it is judged that the extra-high voltage large oil-filled equipment has a discharge fault; if not, it is judged that the extra-high voltage large oil-filled equipment is disturbed.

[0079] The receiving time t of the sound sensor signal of the extra-high voltage large oil-filled equipment at each position is obtained; when t < threshold T1, it is judged that the discharge signal comes from the inside of the equipment; when t > threshold T1, it is judged that the discharge signal occurs outside the equipment.

[0080] Then according to the discharge frequency N i in unit time, when the discharge pulse frequency N i < threshold N1, it is judged as a spike or an occasional discharge; when the discharge pulse frequency > threshold N1, it is judged as a continuous discharge fault.

[0081] Based on the amplitude and pulse number of the electric, acoustic and optical signals, the amplitude and pulse number growth rate is calculated.

[0082] The signal amplitude V0 and pulse number N0 at the initial time are obtained, and the signal amplitude V1 and pulse number N1 after time Δt are obtained, then the amplitude growth rate is calculated according to the formula The pulse number growth rate is calculated according to the formula

[0083] ​Based on the continuous discharge fault, the amplitude and the pulse growth rate are used to characterize the gradual increase of the discharge amplitude from small to large and the gradual increase of the effective discharge times in unit time, further improving the reliability of the alarm signal and the trip signal, when the threshold A1 < growth rate < threshold A2, it is judged as the maintenance signal; when the threshold A2 < growth rate < threshold A3, it is judged as the alarm signal; when the growth rate > threshold A3, it is judged as the trip signal.

[0084] Embodiment two

[0085] As Figure 4 shown, the embodiment provides a new acousto-optic-electric combined monitoring system of an ultra-high voltage large oil-filled equipment, comprising:

[0086] The parameter acquisition module 401 is configured to acquire a discharge parameter of a composite signal of the ultra-high voltage large oil-filled equipment in unit time; the composite signal comprises an acoustic signal, an optical signal and an electrical signal; and the discharge parameter comprises a discharge frequency, a discharge amplitude and a phase of the composite signal.

[0087] The first calculation module 402 is configured to calculate a maximum amplitude, a pulse number and a phase width of the composite signal according to the discharge parameter of the composite signal; and the pulse number is used to quantify the growth degree of the discharge frequency.

[0088] The fault judgment module 403 is configured to judge whether the values of the maximum amplitude, the pulse number and the phase width in a set time increase simultaneously; if yes, it is judged that the ultra-high voltage large oil-filled equipment has a discharge fault; and if no, it is judged that the ultra-high voltage large oil-filled equipment is disturbed.

[0089] The signal source judgment module 404 is configured to, when the ultra-high voltage large oil-filled equipment has a discharge fault, judge a discharge signal source according to a sound sensor signal receiving time at each position of the ultra-high voltage large oil-filled equipment; and the discharge signal source comprises internal discharge and external discharge.

[0090] The fault type judgment module 405 is configured to, when the discharge signal source is internal discharge, judge a discharge fault type according to a discharge frequency in unit time; and the discharge fault type comprises sharp / occasional discharge and continuous discharge fault.

[0091] The second calculation module 406 is configured to, when the discharge fault type is continuous discharge fault, calculate an amplitude growth rate and a pulse number growth rate based on the maximum amplitude and the pulse number of the composite signal.

[0092] The state maintenance module 407 is configured to, according to the amplitude growth rate and the pulse number growth rate, determine a maintenance state of the ultra-high voltage large oil-filled equipment based on a set threshold; and the maintenance state comprises maintenance, alarm and trip.

[0093] Optionally, the signal source judgment module 404 specifically comprises:

[0094] a time acquisition submodule, configured to acquire a receiving time t of the sound sensor signal at each position of the UHV large oil-filled equipment.

[0095] a judgment submodule, configured to judge that the discharge signal is from inside the equipment when t< threshold T1, and judge that the discharge signal occurs outside the equipment when t> threshold T1.

[0096] In summary, the present application has the following technical effects:

[0097] The present application first proposes a new type of sound-light-electricity combined monitoring method for UHV large oil-filled equipment, simultaneously acquires information of three different physical signals of sound, light and electricity, and through fusion analysis of multi-dimensional information, can more comprehensively reflect the real state of the fault, effectively filter out noise and interference in the sound-electricity signal, and provide more reliable diagnosis results, thereby improving the accuracy of fault diagnosis. Through sound-light-electricity combined diagnosis, the fault can be found earlier and more accurately and responded, significantly improving the comprehensiveness, accuracy and reliability of the insulation fault diagnosis of the UHV large oil-filled equipment, reducing the risk of unexpected downtime and equipment damage, and thereby significantly improving the reliability of the UHV large oil-filled equipment and the entire power system.

[0098] The technical features of the above embodiments can be combined in any manner, and to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0099] The principles and implementation modes of the present application are described by applying specific examples in this paper, and the above embodiment descriptions are only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In summary, the content of the present application should not be understood as a limitation.

Claims

1. A new type of acousto-optic-electric combined monitoring method for extra-high voltage large oil-filled equipment, characterized in that, The method comprises the following steps: acquiring discharge parameters of a composite signal of an extra-high voltage large oil-filled equipment in a unit time; the composite signal comprises an acoustic signal, an optical signal and an electrical signal; the discharge parameters comprise a discharge frequency, a discharge amplitude and a phase of the composite signal; calculating a maximum amplitude, a pulse number and a phase width of the composite signal according to the discharge parameters of the composite signal; the pulse number is used to quantify a growth degree of the discharge frequency; judging whether the maximum amplitude, the pulse number and the phase width simultaneously increase in a set time; if yes, judging that the extra-high voltage large oil-filled equipment has a discharge fault; if no, judging that the extra-high voltage large oil-filled equipment is interfered; when the extra-high voltage large oil-filled equipment has a discharge fault, judging a discharge signal source according to a signal receiving time of an acoustic sensor at each position of the extra-high voltage large oil-filled equipment; the discharge signal source comprises internal discharge and external discharge; when the discharge signal source is internal discharge, judging a discharge fault type according to a discharge frequency in a unit time; the discharge fault type comprises a spike / occasional discharge and a continuous discharge fault; when the discharge fault type is the continuous discharge fault, calculating an amplitude growth rate and a pulse number growth rate based on the maximum amplitude and the pulse number of the composite signal; determining a maintenance state of the extra-high voltage large oil-filled equipment based on a set threshold according to the amplitude growth rate and the pulse number growth rate; the maintenance state comprises repair, alarm and tripping.

2. The new type of acousto-optic-electric combined monitoring method for extra-high voltage large oil-filled equipment according to claim 1, characterized in that, The method for calculating the maximum amplitude of the composite signal according to the discharge parameters of the composite signal comprises the following steps: adopting a peak value detection method to determine the maximum amplitude of the composite signal according to a discharge amplitude of the composite signal in a unit time.

3. The new type of acousto-optic-electric combined monitoring method for extra-high voltage large oil-filled equipment according to claim 2, characterized in that, The method for calculating the pulse number of the composite signal according to the discharge parameters of the composite signal comprises the following steps: equally dividing one power frequency cycle into a plurality of phase windows; For each phase window, according to the composite signal in that phase window The number of discharges within the range is used to calculate the number of pulses in the composite signal.

4. The new type of acousto-optic-electric combined monitoring method for extra-high voltage large oil-filled equipment according to claim 3, characterized in that, For each phase window, according to the composite signal in that phase window The number of discharges within the range is used to calculate the number of pulses of the composite signal, specifically including: According to the formula counting the number of pulses of the composite signal; Wherein, M is the total number of power frequency cycles detected in a unit of time, n is is the number of discharges in the phase window for the s-th cycle, N i is the number of pulses.

5. The new type of acousto-optic-electric combined monitoring method for extra-high voltage large oil-filled equipment according to claim 4, characterized in that, The method for calculating the phase width of the composite signal according to the discharge parameters of the composite signal comprises the following steps: According to the formula calculating a phase spread of the complex signal; wherein, is the phase after a unit of time is the phase at t = 0 is the phase spread, T is the power frequency period, and t is the time.

6. The new type of acousto-optic-electric combined monitoring method of the extra-high voltage large oil-filled equipment according to claim 5, characterized in that, When the extra-high voltage large oil-filled equipment has a discharge fault, judging the discharge signal source according to the signal receiving time of the acoustic sensor at each position of the extra-high voltage large oil-filled equipment, which comprises the following steps: acquiring the signal receiving time t of the acoustic sensor at each position of the extra-high voltage large oil-filled equipment; when t < threshold T1, judging that the discharge signal comes from the equipment interior; when t > threshold T1, judging that the discharge signal occurs outside the equipment.

7. The new type of acousto-optic-electric combined monitoring method of the extra-high voltage large oil-filled equipment according to claim 6, characterized in that, When the discharge signal source is internal discharge, judging the discharge fault type according to the discharge frequency in a unit time; the discharge fault type comprises a spike / occasional discharge and a continuous discharge fault, which comprises the following steps: when the pulse number of the composite signal < threshold N1, judging that it is a spike or an occasional discharge; when the pulse number of the composite signal > threshold N1, judging that it is a continuous discharge fault.

8. The new type of acousto-optic-electric combined monitoring method of the extra-high voltage large oil-filled equipment according to claim 7, characterized in that, When the discharge fault type is the continuous discharge fault, calculating the amplitude growth rate and the pulse number growth rate based on the maximum amplitude and the pulse number of the composite signal, which comprises the following steps: According to the formula The amplitude growth rate is calculated; The pulse number growth rate is calculated according to the formula pulse number growth rate = (pulse number at end of interval - pulse number at start Wherein, V0 is the signal amplitude at the initial moment, N0 is the pulse number at the initial moment, Δt is the interval time, V1 is the signal amplitude after time Δt, N1 is the pulse number after time Δt.

9. A new type of acousto-optic-electric combined monitoring system for extra-high voltage large oil-filled equipment, characterized in that, Comprise: The parameter acquisition module is used for acquiring the discharge parameter of the composite signal of the UHV large oil-filled equipment in unit time;The composite signal comprises an acoustic signal, a light signal and an electric signal;The discharge parameter comprises a discharge frequency, a discharge amplitude and a phase of the composite signal; The first calculation module is used for calculating the maximum amplitude, the pulse number and the phase width of the composite signal according to the discharge parameter of the composite signal;The pulse number is used for quantifying the growth degree of the discharge frequency; The fault judgment module is used for judging whether the values of the maximum amplitude, the pulse number and the phase width in a set time are simultaneously increased;If yes, it is judged that the UHV large oil-filled equipment has a discharge fault;If no, it is judged that the UHV large oil-filled equipment is interfered; The signal source judgment module is used for judging the discharge signal source according to the signal receiving time of the acoustic sensor at each position of the UHV large oil-filled equipment when the UHV large oil-filled equipment has a discharge fault;The discharge signal source comprises internal discharge and external discharge; The fault type judgment module is used for judging the discharge fault type according to the discharge frequency in unit time when the discharge signal source is internal discharge;The discharge fault type comprises sharp / occasional discharge and continuous discharge fault; The second calculation module is used for calculating the amplitude growth rate and the pulse number growth rate based on the maximum amplitude and the pulse number of the composite signal when the discharge fault type is continuous discharge fault; The state maintenance module is used for determining the maintenance state of the UHV large oil-filled equipment based on a set threshold according to the amplitude growth rate and the pulse number growth rate;The maintenance state comprises overhaul, alarm and tripping.

10. The new type of acousto-optic-electric combined monitoring system of a UHV large oil-filled equipment according to claim 9, characterized in that, The signal source judgment module specifically comprises: The time acquisition submodule is used for acquiring the signal receiving time t of the acoustic sensor at each position of the UHV large oil-filled equipment; The judgment submodule is used for judging that the discharge signal comes from the equipment interior when t< threshold T1;Judging that the discharge signal occurs outside the equipment when t> threshold T1.

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