AU2021102900A4 - A method and a system for detecting intermittent partial discharge signals - Google Patents
A method and a system for detecting intermittent partial discharge signals Download PDFInfo
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- 238000005070 sampling Methods 0.000 claims abstract description 54
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- 238000012544 monitoring process Methods 0.000 claims abstract description 13
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- 230000007547 defect Effects 0.000 description 18
- 238000003860 storage Methods 0.000 description 14
- 238000003745 diagnosis Methods 0.000 description 4
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- 238000012806 monitoring device Methods 0.000 description 3
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- 238000009413 insulation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The embodiment of the invention discloses a method and a system for detecting intermittent
partial discharge signals, which are used for electrical equipment. The detection method
comprises the following steps: starting from the initial phase of a power grid cycle being 0,
monitoring each pulse signal of electrical equipment synchronously with the power grid cycle.
If it is monitored that any pulse signal of the current power grid cycle meets the trigger
condition at the current time, all pulse signals with preset duration before and after the current
time are collected. Sampling the acquired phase resolved pulse sequence characteristic maps
data of each pulse signal. According to the type of the collected sensor satisfying the trigger
condition and the pulse amplitude of the sampled pulse signal satisfying the trigger condition,
it is determined that the pulse signal satisfying the trigger condition is an intermittent partial
discharge signal or an external interference signal inside the electrical equipment. The
embodiment of the invention can effectively detect intermittent partial discharge signals and
reduce the omission rate.
1/3
FIGURES
S101 Starting from the initial phase of the power grid cycle being , monitoring
each pulse signal of the electrical equipment synchronously with the power
grid cycle.
3102 If it is monitored that any pulse signal of the current power grid cycle meets
the trigger condition at the current time, all pulse signals of preset duration
before and after the current time are collected.
S103 Samplng the collected phase resolved pulse sequence characteristic map
data of each pulse signal.
3104 According to the collected sensor types of pulse signals meeting trigger
conditions and the pulse amplitude of pulse signals meeting trigger
conditions after sampling processing, it is determined that the pulse signals
meeting trigger conditions are intermittent partial discharge signals or
external interference signals inside electrical equipment.
Fig. 1 A flowchart of the method for detecting intermittent partial discharge signals
according to an embodiment of the present invention.
Description
1/3
S101 Starting from the initial phase of the power grid cycle being , monitoring each pulse signal of the electrical equipment synchronously with the power grid cycle. 3102 If it is monitored that any pulse signal of the current power grid cycle meets the trigger condition at the current time, all pulse signals of preset duration before and after the current time are collected. S103 Samplng the collected phase resolved pulse sequence characteristic map data of each pulse signal.
3104 According to the collected sensor types of pulse signals meeting trigger conditions and the pulse amplitude of pulse signals meeting trigger conditions after sampling processing, it is determined that the pulse signals meeting trigger conditions are intermittent partial discharge signals or external interference signals inside electrical equipment.
Fig. 1 A flowchart of the method for detecting intermittent partial discharge signals
according to an embodiment of the present invention.
A method and a system for detecting intermittent partial discharge signals
The invention relates to the technical field of partial discharge, in particular to a method
and a system for detecting intermittent partial discharge signals.
In the process of production, transportation, installation and operation of power
equipment such as GIS, transformer and switchgear, due to manufacturing process,
assembly quality, material aging and mechanical vibration, some defects are inevitable.
Common defects mainly include metal tip defects, free metal particle defects, suspension
defects and solid insulation defects, etc. Partial discharge caused by these defects is not
only a sign of internal insulation deterioration of electrical equipment, but also an
important reason for insulation deterioration.Among the partial discharge signals, some
signals have the characteristics of long intermittent time and sparse discharge. Because
these intermittent partial discharge signals are untimely, they may suddenly discharge for
a period of time or occasionally discharge once, which is not easy to be collected by
online monitoring equipment or easily misjudged as random interference.
At present, there are many live detection devices and on-line monitoring devices used in
partial discharge monitoring. The monitoring data are collected and stored regularly or
regularly by using detection technologies such as ultra high frequency and high frequency
current, which are judged by manual experts or uploaded to the cloud for diagnosis and
analysis. The detection period of live detection is long, and only some defects can be
found. The online monitoring device has a good application effect for the local discharge
with good repeatability. However, for intermittent partial discharge signals, due to the characteristics of uncertain discharge time, scattered frequency, sporadic and sparse, it is difficult for online monitoring devices in the prior art to effectively distinguish intermittent partial discharge signals from random interference signals, resulting in false alarms or missing reports.
The embodiment of the invention provides a method and a system for detecting
intermittent partial discharge signals, so as to solve the problem that it is difficult to
effectively distinguish intermittent partial discharge signals from random interference
signals in the prior art.
In a first aspect, providing a method for detecting intermittent partial discharge signals
for electrical equipment, the method comprising:
The pulse signals of electrical equipment are monitored synchronously with the power
grid cycle from the initial phase of the power grid cycle being 0.
If it is monitored that any pulse signal of the current power grid cycle meets the trigger
condition at the current time, all pulse signals with preset duration before and after the
current time are collected.
Sampling the acquired phase resolved pulse sequence characteristic maps data of each
pulse signal.
According to the type of the collected sensor satisfying the trigger condition and the pulse
amplitude of the sampled pulse signal satisfying the trigger condition, it is determined
that the pulse signal satisfying the trigger condition is an intermittent partial discharge
signal or an external interference signal inside the electrical equipment.
The trigger conditions include:
The pulse amplitude of any pulse signal at the current time of the current power grid
cycle is larger than the pulse threshold of the previous power grid cycle.
Moreover, the pulse signal larger than the pulse threshold of the previous power grid
cycle has the following characteristics: It 0.5Vu - v IT u, It 0.5Vd -tv |T d and t 0.5Vu
< TV < t0.5vd, t0.5vu indicates the time when the pulse signal rises from 0.1 times the
pulse amplitude to 0.5 times the pulse amplitude, T v indicates the time when pulse signal
rises from 0.1 times pulse amplitude to 0.9 times pulse amplitude, t 0.5Vd indicates the
time when pulse signal falls from 0.9 times pulse amplitude to 0.5 times pulse amplitude,
T u indicates the rising pulse width threshold, and T d indicates the falling pulse width
threshold.
In a second aspect, providing a detection system of intermittent partial discharge signals
for electrical equipment, the detection system comprising:
Monitoring module, which is used for monitoring each pulse signal of the electrical
equipment in synchronization with the power grid cycle from the initial phase of the
power grid cycle being 00.
Acquisition module, which is used for acquiring each pulse signal with a preset time
before and after the current time if it is monitored that any pulse signal of the current
power grid cycle meets the trigger condition at the current time.
Sampling module, which is used for sampling the acquired phase resolved pulse sequence
characteristic maps data of each pulse signal.
Determination module, which is configured to determine that the pulse signal meeting the
trigger condition is an intermittent partial discharge signal or an external interference
signal inside the electrical equipment according to the type of the sensor of the collected pulse signal meeting the trigger condition and the pulse amplitude of the pulse signal meeting the trigger condition after sampling processing.
The trigger conditions include:
The pulse amplitude of any pulse signal at the current time of the current power grid
cycle is larger than the pulse threshold of the previous power grid cycle.
Moreover, the pulse signal larger than the pulse threshold of the previous power grid
cycle has the following characteristics: It 0.5Vu -t v IST u, t 0.5Vd -t v ST d and t 0.5Vu
< TV < t0.5vd, t0.5vu indicates the time when the pulse signal rises from 0.1 times the
pulse amplitude to 0.5 times the pulse amplitude, T v indicates the time when pulse signal
rises from 0.1 times pulse amplitude to 0.9 times pulse amplitude, t 0.5Vd indicates the
time when pulse signal falls from 0.9 times pulse amplitude to 0.5 times pulse amplitude,
T u indicates the rising pulse width threshold, and T d indicates the falling pulse width
threshold.
In this way, the embodiment of the invention can effectively detect intermittent partial
discharge signals, especially for abnormal electrical equipment, and continuously collect
the intermittent partial discharge signals in real time under the condition that power
failure is impossible to overhaul, and adopt a trigger collection mechanism to extract
occasional and sparse intermittent partial discharge signals, thereby avoiding the
occurrence of intermittent partial discharge signal omission caused by timing collection
and reducing the partial discharge signal omission rate. At the same time, it only needs to
collect the data at the triggering time of the storage signal, which reduces the requirement
of storage resources and solves the contradiction between high sampling rate and low
storage resources. By comparing the signals of noise sensor and ultrahigh frequency sensor, intermittent partial discharge signals and external interference signals can be effectively distinguished, so as to further improve the accuracy of defect diagnosis.
In order to explain the technical scheme of the embodiments of the present invention
more clearly, the figures used in the description of the embodiments of the present
invention will be briefly introduced below. Obviously, the figures in the following
description are only some embodiments of the present invention, and other figures can be
obtained according to these figures without paying creative labor.
Fig. 1 is a flowchart of the method for detecting intermittent partial discharge signals
according to an embodiment of the present invention.
Fig. 2 is a functional flow chart of data collected according to a preferred embodiment of
the present invention.
Fig. 3 is a structural block diagram of the system for detecting intermittent partial
discharge signals according to an embodiment of the present invention.
In the following, the technical scheme in the embodiments of the present invention will
be described clearly and completely with reference to the figures in the embodiments of
the present invention. Obviously, the described embodiments are part of the embodiments
of the present invention, not all of them. Based on the embodiments of the present
invention, all other embodiments obtained by ordinary technicians in the field without
creative labor belong to the scope of protection of the present invention.
The embodiment of the invention discloses a method for detecting intermittent partial
discharge signals. The detection method is used for electrical equipment, such as GIS, transformer and switchgear. As shown in fig. 1, the detection method includes the following steps:
Si01: starting from the initial phase of the power grid cycle being 0, monitoring each
pulse signal of the electrical equipment synchronously with the power grid cycle.
A power grid cycle is generally 0.02s. Specifically, it can be monitored and cached by
FPGA chip. It should be understood that the following steps can be stopped when the
total number of buffered single pulses reaches the maximum number of buffered pulses,
and the following steps can be performed when the total number of buffered single pulses
is less than the maximum number of buffered pulses.
Generally, a plurality of sensors can be provided, and each sensor is responsible for each
pulse signal. For example, taking GIS equipment as an example, sensors can be deployed
on GIS equipment.
S102: if it is monitored that any pulse signal of the current power grid cycle meets the
trigger condition at the current time, all pulse signals of preset duration before and after
the current time are collected.
The preset duration before and after the current time refers to a time interval formed by
the time before the current time, the current time and the continuous time after the current
time. Generally, the selected time before the current time is shorter than that after the
current time, which can be determined by experience. The specific duration of the preset
duration can also be set by experience, for example, the preset duration is Is.
Specifically, the trigger conditions include:
(1) The pulse amplitude of any pulse signal at the current time of the current power grid
cycle is larger than the pulse threshold of the previous power grid cycle.
It should be understood that pulse amplitude refers to the maximum amplitude of pulse
changing from "0" to "1".
Specifically, the pulse threshold of the previous power grid cycle is calculated by the
following formula:
In which N j represents the pulse threshold of the monitored j-th power grid cycle, it
should be understood that the current power grid cycle is the j+1-th power grid cycle. m
represents the total number of monitored power grid cycles, n represents the total number
of equally divided intervals of each power grid cycle, which can be set by experience. F ij
represents the maximum pulse amplitude of the pulse signal in the i-th interval of the
monitored j-th power grid cycle, and the pulse amplitude can be obtained by
measurement, so that the maximum pulse amplitude can be determined from it. k
represents the margin coefficient, which can be determined by experience, 1<k<SNR, and
SNR represents the signal-to-noise ratio, which can be obtained by measurement.
(2) The pulse signal larger than the pulse threshold of the previous power grid cycle has
the following characteristics:
It 0.5Vu - v I<T u .
It 0.5Vd -tv I<T d.
t 0.5Vu <t v <t 0.5Vd .
t 0.5Vu represents the time when the pulse signal rises from 0.1 times the pulse amplitude
to 0.5 times the pulse amplitude. t v indicates the time when the pulse signal rises from
0.1 times the pulse amplitude to 0.9 times the pulse amplitude. t 0.5Vd indicates the time
when the pulse signal drops from 0.9 times the pulse amplitude to 0.5 times the pulse
amplitude. t u represents the rising pulse width threshold, which can be preset by experience, in a preferred embodiment of the present invention, the value is Oms. T d represents the falling pulse width threshold, which can be preset by experience, in a preferred embodiment of the present invention, the value is 20ms.
In practice, when the trigger condition is reached, the pulse signals before and after the
trigger can be stored by FPGA chip instead of storing all the pulse data. The location of
partial discharge defects requires a high sampling frequency of ultrahigh frequency,
which leads to a large amount of data. By adopting this trigger method for acquisition and
storage, the amount of stored data can be reduced, and the storage resource requirements
caused by high sampling rate can be reduced.
S103: sampling the collected phase resolved pulse sequence characteristic map data of
each pulse signal.
Specifically, the sampling process is carried out as follows:
(1) According to the sampling ratio of phase resolved pulse sequence characteristic map,
the number of points of pulse signal collected each time is divided into multiple intervals.
Where interval number = number of points/sampling ratio of pulse signal. Generally, the
pulse data of partial discharge signals can be acquired by two acquisition modes: pulse
acquisition and phase resolved pulse sequence characteristic map (PRPS) acquisition.
According to the embodiment of the invention, phase resolved pulse sequence
characteristic map data is adopted to judge whether a pulse signal is an intermittent
partial discharge signal.
(2) In each interval, the point with the maximum pulse amplitude of the pulse signal is
taken as the sampling of the phase resolved pulse sequence characteristic map.
Because the pulse amplitude of each pulse signal may be different, the pulse signal with
the largest pulse amplitude in the interval is selected as the sample.
S104: according to the collected sensor types of pulse signals meeting trigger conditions
and the pulse amplitude of pulse signals meeting trigger conditions after sampling
processing, it is determined that the pulse signals meeting trigger conditions are
intermittent partial discharge signals or external interference signals inside electrical
equipment.
Sensors adopted by the embodiment of the invention include an ultrahigh frequency
sensor and a noise sensor. The sampling rate of ultrahigh frequency sensor is 2.5GHz.
Sampling rate of noise sensor is 2.5GHz. Because there are many interferences on
ultrahigh frequency partial discharge signals, and the characteristics of interference
signals are similar to those of partial discharge signals, noise sensors should be used to
eliminate the spatial interference of ultrahigh frequency partial discharge signals.
According to specific needs, different numbers of corresponding sensors can be set. In a
preferred embodiment of the present invention, three ultrahigh frequency sensors and one
noise sensor can be provided.
Specifically, this step includes the following situations:
(1) Only the noise sensor collects the pulse signal that meets the trigger condition.
If the sensor that collects the pulse signal satisfying the trigger condition is a noise
sensor, it is determined that the pulse signal satisfying the trigger condition is an external
interference signal.
(2) Only the ultrahigh frequency sensor collects the pulse signal that meets the trigger
condition.
If the sensor that collects the pulse signal satisfying the trigger condition is an ultrahigh
frequency sensor, it is determined that the pulse signal satisfying the trigger condition is
an intermittent partial discharge signal inside the electrical equipment.
(3) Both ultrahigh frequency sensors and noise sensors have collected pulse signals that
meet the triggering conditions.
(1) If the sensors collecting pulse signals satisfying trigger conditions include ultrahigh
frequency sensors and noise sensors, it is judged whether the characteristics of phase
resolved pulse sequence characteristic maps of pulse signals satisfying trigger conditions
collected by ultrahigh frequency sensors and noise sensors are the same.
Among them, the characteristics of phase resolved pulse sequence characteristic map
refer to discharge times, skewness, prominence, asymmetry, correlation coefficient, pulse
concentration and dispersion. These characteristics can be obtained by counting the
discharge frequency phase distribution, discharge amplitude phase distribution and
discharge frequency periodic distribution of phase resolved pulse sequence characteristic
map.
(2) If the characteristics of phase resolved pulse sequence characteristic maps of pulse
signals satisfying trigger conditions collected by ultrahigh frequency sensors are different
from those of pulse signals satisfying trigger conditions collected by noise sensors, it is
determined that the pulse signals satisfying trigger conditions collected by ultrahigh
frequency sensors are intermittent partial discharge signals inside electrical equipment.
It should be understood that in this case, the pulse signal collected by the noise sensor
that meets the trigger condition is an external interference signal.
(3) If the characteristics of phase resolved pulse sequence characteristic maps of pulse
signals satisfying trigger conditions collected by ultrahigh frequency sensors are the same
as those of pulse signals satisfying trigger conditions collected by noise sensors, compare
the pulse amplitudes of pulse signals satisfying trigger conditions collected by ultrahigh
frequency sensors with those of pulse signals satisfying trigger conditions collected by
noise sensors.
It should be understood that the pulse amplitude of the pulse signal collected by the
ultrahigh frequency sensor and the pulse amplitude of the pulse signal collected by the
noise sensor for comparison are pulse signals collected at the same time.
(4) If the pulse amplitude of the pulse signal satisfying the trigger condition collected by
the ultrahigh frequency sensor is not smaller than that of the pulse signal satisfying the
trigger condition collected by the noise sensor, it is determined that the pulse signal
satisfying the trigger condition collected by ultrahigh frequency is an intermittent partial
discharge signal inside the electrical equipment.
It should be understood that in this case, the pulse signal collected by the noise sensor
that meets the trigger condition is an external interference signal.
(5) If the pulse amplitude of the pulse signal which meets the trigger condition collected
by the ultrahigh frequency sensor is smaller than that of the pulse signal which meets the
trigger condition collected by the noise sensor, it is determined that the pulse signal
which meets the trigger condition collected by the ultrahigh frequency sensor is an
external interference signal.
It should be understood that in this case, the pulse signal collected by the noise sensor
that meets the trigger condition is an external interference signal.
In addition, after the intermittent partial discharge signal in the electrical equipment is
determined by the detection method of the embodiment of the invention, the defect type
can be identified and the position of the defect can be determined according to the
intermittent partial discharge signal.
As shown in fig. 2, in the process of collecting pulse signals, the pulse signals can also be
collected by ultrasonic sensors with a sampling rate of 1MHz, and specifically, three
ultrasonic sensors can be provided. The location of defects can be determined by using
ultrahigh frequency 2.5GHz pulse spectrum data of intermittent partial discharge signals
collected by ultrahigh frequency sensors (without sampling) and by using ultrasonic
1MHz pulse spectrum data of intermittent partial discharge signals collected by ultrasonic
sensors (without sampling). The location of defects can also be determined by using the
ultrahigh frequency 1GHz pulse map data of intermittent partial discharge signals
collected by ultrahigh frequency sensors (pre-sampling is required) and the ultrasonic
1MHz pulse map data of intermittent partial discharge signals collected by ultrasonic
sensors (pre-sampling is not required).
The defect types can be diagnosed by existing methods using ultrahigh frequency phase
resolved pulse sequence characteristic map data (pre-sampling is required) of intermittent
partial discharge signals collected by ultrahigh frequency sensors, ultrasonic phase
resolved pulse sequence characteristic map data (pre-sampling is required) of intermittent
partial discharge signals collected by ultrasonic sensors and noise phase resolved pulse
sequence characteristic map data (pre-sampling is required) collected by noise sensors.
Combining the results of the above-mentioned joint judgments, we can get more accurate
positions and types of defects. Among them, the sampling method of phase resolved pulse sequence characteristic map data is as described above. The sampling method of ultrahigh frequency pulse map data is to divide the stored pulse points into equal intervals according to the sampling frequency of ultrasonic waves, and the interval number is equal to the sampling frequency of ultrasonic waves, and the point with the largest pulse amplitude in the interval is taken as the sampling of ultrahigh frequency pulse map.
In summary, the intermittent partial discharge signal detection method of the embodiment
of the present invention can effectively detect the intermittent partial discharge signal,
especially for the electrical equipment with abnormality, the intermittent partial discharge
signal can be continuously collected in real time under the condition of failure to
overhaul, and the occasional and sparse intermittent partial discharge signal can be
extracted by adopting the trigger collection mechanism, thus avoiding the occurrence of
intermittent partial discharge signal missing caused by timing collection. The missing rate
of partial discharge signals is reduced, and only the data at the triggering time of the
storage signals need to be collected, which reduces the requirement of storage resources
and solves the contradiction between high sampling rate and low storage resources. By
comparing the signals of noise sensors and ultrahigh frequency sensors, intermittent
partial discharge signals and external interference signals can be effectively
distinguished, so as to further improve the accuracy of defect diagnosis.
The embodiment of the invention also discloses a system for detecting intermittent partial
discharge signals. The detection system is used for electrical equipment. As shown in fig.
3, the detection system includes:
Monitoring module 301, which is used for monitoring each pulse signal of the electrical
equipment in synchronization with the power grid cycle from the initial phase of the
power grid cycle being 0.
Acquisition module 302, which is used for acquiring each pulse signal with a preset time
before and after the current time if it is monitored that any pulse signal of the current
power grid cycle meets the trigger condition at the current time.
Sampling module 303, which is used for sampling the acquired pulse sequence phase
characteristic maps data of each pulse signal.
Determination module 304, which is configured to determine that the pulse signal
meeting the trigger condition is an intermittent partial discharge signal or an external
interference signal inside the electrical equipment according to the type of the sensor of
the collected pulse signal meeting the trigger condition and the pulse amplitude of the
pulse signal meeting the trigger condition after sampling processing.
The trigger conditions include:
The pulse amplitude of any pulse signal at the current time of the current power grid
cycle is larger than the pulse threshold of the previous power grid cycle.
The formula for calculating the pulse threshold of the previous power grid cycle is as
follows:
In which N j represents the pulse threshold of the monitored j-th power grid cycle, m
represents the total number of monitored power grid cycles, n represents the total number
of equally divided intervals of each power grid cycle, F ij represents the maximum pulse
amplitude of the pulse signal in the i-th interval of the monitored j-th power grid cycle, k represents the margin coefficient, 1<k<SNR, and SNR represents the signal-to-noise ratio.
Moreover, the pulse signal larger than the pulse threshold of the previous power grid
cycle has the following characteristics: It 0.5Vu -t v IST u, t 0.5Vd -t v IST d and t 0.5Vu
< TV < t0.5vd, t0.5vu indicates the time when the pulse signal rises from 0.1 times the
pulse amplitude to 0.5 times the pulse amplitude, T v indicates the time when pulse signal
rises from 0.1 times pulse amplitude to 0.9 times pulse amplitude, t 0.5Vd indicates the
time when pulse signal falls from 0.9 times pulse amplitude to 0.5 times pulse amplitude,
T u indicates the rising pulse width threshold, and T d indicates the falling pulse width
threshold.
Preferably, the determining module 304 includes:
First determination sub-module, if the sensor which collects the pulse signal meeting the
trigger condition is a noise sensor, determining that the pulse signal meeting the trigger
condition is an external interference signal.
Second determination sub-module, determining that the pulse signal meeting the trigger
condition is an intermittent partial discharge signal inside the electrical equipment if the
sensor which collects the pulse signal meeting the trigger condition is an ultrahigh
frequency sensor.
Preferably, the determining module 304 further includes:
Judging sub-module, judging whether the characteristics of pulse sequence phase
characteristic maps of pulse signals satisfying the triggering conditions collected by the
ultrahigh frequency sensor and the noise sensor are the same if the sensors collecting the pulse signals satisfying the triggering conditions include ultrahigh frequency sensors and noise sensors.
Third determination sub-module, if the characteristics of pulse sequence phase
characteristic maps of pulse signals which meet the triggering conditions collected by the
ultrahigh frequency sensor are different from those of pulse signals which meet the
triggering conditions collected by the noise sensor, determining that the pulse signals
which meet the triggering conditions collected by the ultrahigh frequency sensor are
intermittent partial discharge signals inside the electrical equipment.
Comparison sub-module, comparing the pulse amplitude of the pulse signal satisfying the
trigger condition collected by the ultrahigh frequency sensor with that of the noise sensor
if the characteristics of the pulse sequence phase characteristic map of the pulse signal
satisfying the trigger condition are the same.
Fourth determination sub-module, if the pulse amplitude of the pulse signal which meets
the trigger condition collected by the ultrahigh frequency sensor is not smaller than that
of the pulse signal which meets the trigger condition collected by the noise sensor,
determining that the pulse signal which meets the trigger condition collected by the
ultrahigh frequency sensor is an intermittent partial discharge signal inside electrical
equipment.
Fifth determination sub-module, if the pulse amplitude of the pulse signal which meets
the trigger condition collected by the ultrahigh frequency sensor is smaller than that of
the pulse signal which meets the trigger condition collected by the noise sensor,
determining that the pulse signal which meets the trigger condition collected by the
ultrahigh frequency sensor is an external interference signal.
Preferably, the sampling module 303 includes:
Dividing sub-module, configured to divide the number of points of the pulse signal
collected each time into a plurality of intervals according to the sampling ratio of the
pulse sequence phase characteristic map, wherein the number of intervals is equal to the
number of points of the pulse signal/sampling ratio.
Sampling sub-module, which is used for extracting the point with the largest pulse
amplitude of the pulse signal in each interval as the sampling of the pulse sequence phase
characteristic map.
As for the device embodiment, because it is basically similar to the method embodiment,
the description is relatively simple, and relevant points can be found in the partial
description of the method embodiment.
In summary, the intermittent partial discharge signal detection system of the embodiment
of the present invention can effectively detect the intermittent partial discharge signal,
especially for the electrical equipment with abnormality, the intermittent partial discharge
signal can be continuously collected in real time under the condition of failure to
overhaul, and the occasional and sparse intermittent partial discharge signal can be
extracted by adopting the trigger collection mechanism, thus avoiding the occurrence of
intermittent partial discharge signal missing caused by timing collection. The missing rate
of partial discharge signals is reduced, and only the data at the triggering time of the
storage signals need to be collected, which reduces the requirement of storage resources
and solves the contradiction between high sampling rate and low storage resources. By
comparing the signals of noise sensors and ultrahigh frequency sensors, intermittent partial discharge signals and external interference signals can be effectively distinguished, so as to further improve the accuracy of defect diagnosis.
Those of ordinary skill in the art can realize that the units and algorithm steps of each
embodiment described in connection with the embodiments disclosed in the embodiments
of the present invention can be realized in electronic hardware, or a combination of
computer software and electronic hardware. Whether these functions are implemented in
hardware or software depends on the specific application and design constraints of the
technical scheme. Professionals can use different methods to implement the described
functions for each specific application, but such implementation should not be considered
outside the scope of the present invention.
It can be clearly understood by those skilled in the art that for the convenience and
conciseness of description, the specific working processes of the systems, devices and
units described above can refer to the corresponding processes in the aforementioned
method embodiments, and will not be described in detail here.
In the embodiments provided in this application, it should be understood that the
disclosed device and method can be realized in other ways. For example, the device
embodiment described above is only schematic. For example, the division of the unit is
only a logical function division. In actual implementation, there may be another division
mode, for example, multiple units or components can be combined or integrated into
another system, or some features can be ignored or not implemented. On the other hand,
the mutual coupling or direct coupling or communication connection shown or discussed
may be indirect coupling or communication connection through some interfaces, devices
or units, and may be in electrical, mechanical or other forms.
The units described as separated components may or may not be physically separated,
and the components displayed as units may or may not be physical units, that is, they may
be located in one place or distributed to multiple network units. Some or all of the units
can be selected according to actual needs to achieve the purpose of this embodiment.
In addition, each functional unit in each embodiment of the present invention may be
integrated into one processing unit, or each unit may physically exist separately, or two or
more units may be integrated into one unit.
If the functions are realized in the form of software functional units and sold or used as
independent products, they can be stored in a computer readable storage medium. Based
on this understanding, the technical solution of the present invention can be embodied in
the form of a software product, which is stored in a storage medium and includes several
instructions to make a computer device (which can be a personal computer, a server, or a
network device, etc.) execute all or part of the steps of the method described in each
embodiment of the present invention. The aforementioned storage media include: U disk,
mobile hard disk, ROM, RAM, magnetic disk or optical disk, etc.
The above is only a specific embodiment of the present invention, but the protection
scope of the present invention is not limited to this. Any person familiar with the
technical field can easily think of changes or substitutions within the technical scope
disclosed by the present invention, which should be covered within the protection scope
of the present invention. Therefore, the protection scope of the present invention shall be
subject to the protection scope of the claims.
Claims (10)
1. A method for detecting intermittent partial discharge signals used in electrical
equipment, which is characterized by comprising:
The pulse signals of electrical equipment are monitored synchronously with the power
grid cycle from the initial phase of the power grid cycle being 0.
If it is monitored that any pulse signal of the current power grid cycle meets the trigger
condition at the current time, all pulse signals with preset duration before and after the
current time are collected.
Sampling the acquired phase resolved pulse sequence characteristic maps data of each
pulse signal.
According to the type of the collected sensor satisfying the trigger condition and the pulse
amplitude of the sampled pulse signal satisfying the trigger condition, it is determined
that the pulse signal satisfying the trigger condition is an intermittent partial discharge
signal or an external interference signal inside the electrical equipment.
The trigger conditions include:
The pulse amplitude of any pulse signal at the current time of the current power grid
cycle is larger than the pulse threshold of the previous power grid cycle.
Moreover, the pulse signal larger than the pulse threshold of the previous power grid
cycle has the following characteristics: It 0.5Vu - v IT u, It 0.5Vd -tv |T d and t 0.5Vu
< TV < t.5vd, tO.5vu indicates the time when the pulse signal rises from 0.1 times the
pulse amplitude to 0.5 times the pulse amplitude, T v indicates the time when pulse signal
rises from 0.1 times pulse amplitude to 0.9 times pulse amplitude, t 0.5Vd indicates the
time when pulse signal falls from 0.9 times pulse amplitude to 0.5 times pulse amplitude,
T u indicates the rising pulse width threshold, and T d indicates the falling pulse width
threshold.
2. The detection method according to claim 1, characterized in that the calculation
formula of the pulse threshold of the previous power grid cycle is as follows:
In which N j represents the pulse threshold of the monitored j-th power grid cycle, m
represents the total number of monitored power grid cycles, n represents the total number
of equally divided intervals of each power grid cycle, F ij represents the maximum pulse
amplitude of the pulse signal in the i-th interval of the monitored j-th power grid cycle, k
represents the margin coefficient, 1<k<SNR, and SNR represents the signal-to-noise
ratio.
3. The detection method according to claim 1, characterized in that the step of
determining that the pulse signal satisfying the trigger condition is an intermittent partial
discharge signal inside the electrical equipment or an external interference signal
comprises:
If the sensor which collects the pulse signal meeting the trigger condition is a noise
sensor, determining that the pulse signal meeting the trigger condition is an external
interference signal.
If the sensor which collects the pulse signal meeting the trigger condition is an ultrahigh
frequency sensor, determining that the pulse signal meeting the trigger condition is an
intermittent partial discharge signal inside the electrical equipment.
4. The detection method according to claim 1, characterized in that the step of
determining that the pulse signal satisfying the trigger condition is an intermittent partial discharge signal inside the electrical equipment or an external interference signal further comprises:
If the sensor collecting the pulse signal satisfying the triggering condition includes an
ultrahigh frequency sensor and a noise sensor, it is judged whether the characteristics of
the phase resolved pulse sequence characteristic map of the pulse signal satisfying the
triggering condition collected by the ultrahigh frequency sensor and the pulse signal
satisfying the triggering condition collected by the noise sensor are the same.
If the characteristics of phase resolved pulse sequence characteristic maps of pulse
signals which meet the triggering conditions collected by the ultrahigh frequency sensor
are different from those of pulse signals which meet the triggering conditions collected by
the noise sensor, determining that the pulse signals which meet the triggering conditions
collected by the ultrahigh frequency sensor are intermittent partial discharge signals
inside the electrical equipment.
If the characteristics of the phase resolved pulse sequence characteristic map of the pulse
signal satisfying the triggering condition collected by the ultrahigh frequency sensor and
the pulse signal satisfying the triggering condition collected by the noise sensor are the
same, then, the pulse amplitude of the pulse signal satisfying the triggering condition
collected by the ultrahigh frequency sensor is compared with the pulse amplitude of the
pulse signal satisfying the triggering condition collected by the noise sensor.
If the pulse amplitude of the pulse signal which meets the trigger condition collected by
the ultrahigh frequency sensor is not smaller than that of the pulse signal which meets the
trigger condition collected by the noise sensor, determining that the pulse signal which meets the trigger condition collected by the ultrahigh frequency sensor is an intermittent partial discharge signal inside electrical equipment.
If the pulse amplitude of the pulse signal which meets the trigger condition collected by
the ultrahigh frequency sensor is smaller than that of the pulse signal which meets the
trigger condition collected by the noise sensor, determining that the pulse signal which
meets the trigger condition collected by the ultrahigh frequency sensor is an external
interference signal.
5. The detection method according to claim 1, characterized in that the step of sampling
the acquired phase resolved pulse sequence characteristic map data of each pulse signal
comprises:
According to the sampling ratio of phase resolved pulse sequence characteristic map, the
number of points of pulse signal collected each time is divided into multiple intervals,
where the number of intervals is equal to the number of points of pulse signal/sampling
ratio.
Extracting the point with the maximum pulse amplitude of the pulse signal in each
interval as the sampling of the phase resolved pulse sequence characteristic map.
6. A detection system of intermittent partial discharge signals for electrical equipment,
characterized in that the detection system comprises:
Monitoring module, which is used for monitoring each pulse signal of the electrical
equipment in synchronization with the power grid cycle from the initial phase of the
power grid cycle being 0.
Acquisition module, which is used for acquiring each pulse signal with a preset time
before and after the current time if it is monitored that any pulse signal of the current
power grid cycle meets the trigger condition at the current time.
Sampling module, which is used for sampling the acquired phase resolved pulse sequence
characteristic maps data of each pulse signal.
Determination module, which is configured to determine that the pulse signal meeting the
trigger condition is an intermittent partial discharge signal or an external interference
signal inside the electrical equipment according to the type of the sensor of the collected
pulse signal meeting the trigger condition and the pulse amplitude of the pulse signal
meeting the trigger condition after sampling processing.
7. The detection system according to claim 6, characterized in that the calculation
formula of the pulse threshold of the previous power grid cycle is as follows:
8. The detection system according to claim 6, characterized in that the determination
module comprises:
First determination sub-module, if the sensor which collects the pulse signal meeting the
trigger condition is a noise sensor, determining that the pulse signal meeting the trigger
condition is an external interference signal.
Second determination sub-module, determining that the pulse signal meeting the trigger
condition is an intermittent partial discharge signal inside the electrical equipment if the
sensor which collects the pulse signal meeting the trigger condition is an ultrahigh
frequency sensor.
9. The detection system according to claim 6, characterized in that the determination
module further comprises:
Judging sub-module, judging whether the characteristics of phase resolved pulse
sequence characteristic maps of pulse signals satisfying the triggering conditions
collected by the ultrahigh frequency sensor and the noise sensor are the same if the
sensors collecting the pulse signals satisfying the triggering conditions include ultrahigh
frequency sensors and noise sensors.
Third determination sub-module, if the characteristics of phase resolved pulse sequence
characteristic maps of pulse signals which meet the triggering conditions collected by the
ultrahigh frequency sensor are different from those of pulse signals which meet the
triggering conditions collected by the noise sensor, determining that the pulse signals
which meet the triggering conditions collected by the ultrahigh frequency sensor are
intermittent partial discharge signals inside the electrical equipment.
Comparison sub-module, comparing the pulse amplitude of the pulse signal satisfying the
trigger condition collected by the ultrahigh frequency sensor with that of the noise sensor
if the characteristics of the phase resolved pulse sequence characteristic map of the pulse
signal satisfying the trigger condition are the same.
Fourth determination sub-module, if the pulse amplitude of the pulse signal which meets
the trigger condition collected by the ultrahigh frequency sensor is not smaller than that
of the pulse signal which meets the trigger condition collected by the noise sensor,
determining that the pulse signal which meets the trigger condition collected by the
ultrahigh frequency sensor is an intermittent partial discharge signal inside electrical
equipment.
Fifth determination sub-module, if the pulse amplitude of the pulse signal which meets
the trigger condition collected by the ultrahigh frequency sensor is smaller than that of the pulse signal which meets the trigger condition collected by the noise sensor, determining that the pulse signal which meets the trigger condition collected by the ultrahigh frequency sensor is an external interference signal.
10. The detection system according to claim 6, characterized in that the sampling module
comprises:
Dividing sub-module, configured to divide the number of points of the pulse signal
collected each time into a plurality of intervals according to the sampling ratio of the
phase resolved pulse sequence characteristic map, wherein the number of intervals is
equal to the number of points of the pulse signal/sampling ratio.
Sampling sub-module, which is used for extracting the point with the largest pulse
amplitude of the pulse signal in each interval as the sampling of the phase resolved pulse
sequence characteristic map.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102900A AU2021102900A4 (en) | 2021-05-27 | 2021-05-27 | A method and a system for detecting intermittent partial discharge signals |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102900A AU2021102900A4 (en) | 2021-05-27 | 2021-05-27 | A method and a system for detecting intermittent partial discharge signals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2021102900A4 true AU2021102900A4 (en) | 2021-07-15 |
Family
ID=76785339
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2021102900A Ceased AU2021102900A4 (en) | 2021-05-27 | 2021-05-27 | A method and a system for detecting intermittent partial discharge signals |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU2021102900A4 (en) |
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2021
- 2021-05-27 AU AU2021102900A patent/AU2021102900A4/en not_active Ceased
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