CN107271833A - A kind of electric transmission line isolator On-line Monitoring of Leakage Current method and its system - Google Patents
A kind of electric transmission line isolator On-line Monitoring of Leakage Current method and its system Download PDFInfo
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- CN107271833A CN107271833A CN201710415303.3A CN201710415303A CN107271833A CN 107271833 A CN107271833 A CN 107271833A CN 201710415303 A CN201710415303 A CN 201710415303A CN 107271833 A CN107271833 A CN 107271833A
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2506—Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
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Abstract
It is high to solve existing insulator leakage current monitoring system data communication cost the invention discloses a kind of electric transmission line isolator On-line Monitoring of Leakage Current method and its system, and the low technical problem of leakage current monitoring result accuracy rate.This method comprises the following steps：The leakage current signal of each insulator on transmission line of electricity is obtained in real time, and the leakage current signal is sent to by remote monitoring center by cordless communication network；The remote monitoring center receives and stores the leakage current signal, and the aperiodic component and periodic component of the leakage current signal are separated by Fourier transform, remove the intrinsic frequency interference in the periodic component, and passage time Scale Decomposition removes the noise of aperiodic component, the aperiodic component after denoising and the periodic component are then reconstructed into the leakage current signal；When the leakage current signal is more than default leakage current threshold value, the remote monitoring center sends alarm.
Description
Technical field
The present invention relates to electrical equipment technical field, and in particular to a kind of electric transmission line isolator On-line Monitoring of Leakage Current
Method and its system.
Background technology
Insulator in high-voltage transmission line is responsible for the double action of electric insulation and mechanical support, it is ensured that transmission line of electricity
Can normally it be run under overvoltage feelings, the working condition of insulator plays the safe and reliable operation to power system particularly important
Effect.Related data shows that the extent of injury of high-voltage transmission line insulator pollution flashover accident and the economic loss caused are own to pass through
Considerably beyond the influence of switching overvoltage and lightning impulse overvoltage to power system.In order to prevent the generation of pollution flashover accident,
Need to make the situation of staining of insulator judgement promptly and accurately, before danger is arrived, to take necessary measure.Electricity
Power department generally uses the number of insulator in increase insulator chain, applies hydrophobic painting using anti-pollution insulator, in insulator surface
Expect, carry out several Flash Decontamination Measurements such as periodic cleaning using composite organic insulator, to insulator.These methods are in insulator
Positive effect is all played in actual motion, but can not in real time, dynamically, comprehensively reflect the pollution condition of insulator, it is impossible to
Accomplish the generation of Prevent from Dirt Flash accident in advance.Therefore, the insulator on-line monitoring system for being adapted to power system demand is developed, entirely
The operation conditions of the monitoring high-voltage fence insulator of weather, the generation of operation of power networks failure is avoided to take measures in advance, is carried
The safety and reliability of high operation of power networks, promotes insulator to have from current scheduled overhaul to repair based on condition of component transition important
Meaning.
The pollution flashover phenomenon of insulator be derived from various key element, such as thermodynamics, chemistry and by electricity cause to be influenceed.In insulation
The top layer of son, if heat power will reach that balance generally entails the arc over of locality.It is specific to judge that insulator pollutes by filth
Degree when, selectable index contain top layer electrical conductivity, flashover field strength factor, cable leakage electric current, equivalent attached salt it is close
Degree.In these key elements, the specific size of current of terminal leakage is related to weather, retting-flax wastewater, filthy degree etc. at that time.Electricity
Operationally, power network can provide the monitoring information of real-time to cable, hereby it is possible to measure insulator state during operation.It is existing exhausted
Edge system for monitoring leakage current, obtains the leakage current on insulator generally by current sensor, then, passes through
GPRS GSM the communication technology such as CDMA be transferred to Surveillance center；Current system for monitoring leakage current has that noise is big, precision not
Height, and the problems such as communication cost height, accordingly, it would be desirable to it is further perfect, optimization insulator leakage current monitoring system
Performance.
The content of the invention
It is an object of the invention to provide a kind of electric transmission line isolator On-line Monitoring of Leakage Current method and its system, use
It is high to solve existing insulator leakage current monitoring system data communication cost, and leakage current monitoring result accuracy rate is low
Technical problem.
To achieve the above object, the inventive method is believed with obtaining the leakage current on insulator in real time by current sensor
Number, the data communication of leakage current signal and Surveillance center is then realized by cordless communication network, then passes through Fourier
Conversion and time scale, which are decomposed, to carry out denoising to leakage current signal, it is proposed that a kind of electric transmission line isolator leakage electricity
Flow on-line monitoring method.Specifically, this method comprises the following steps：
The leakage current signal of each insulator on transmission line of electricity is obtained in real time, by cordless communication network by the leakage
Current signal is sent to remote monitoring center；
The remote monitoring center receives and stores the leakage current signal, and by being let out described in Fourier transform separation
The aperiodic component and periodic component of leakage current signal, remove the intrinsic frequency interference in the periodic component, and passage time
Scale Decomposition removes the noise of aperiodic component, and the aperiodic component after denoising and the periodic component then are reconstructed into institute
State leakage current signal；
When the leakage current signal is more than default leakage current threshold value, the remote monitoring center sends alarm and carried
Show.
Further, the electric transmission line isolator On-line Monitoring of Leakage Current method also includes：Power transmission line is obtained in real time
Atmospheric particulates (APM) index on road near the temperature of each insulator surface, humidity data, and the insulator, and
The remote monitoring center will be sent to by cordless communication network.
Further, the remote monitoring center is according to the leakage current signal, temperature, the humidity, described big
Aerated particle thing index generates corresponding leakage current signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve,
Obtain the leakage current signal and the temperature, the humidity, the relation property of the Atmospheric particulates.
Further, the cordless communication network by multiple setting sensor nodes on the insulator by ZigBee without
Line communication protocol and intermediate node are constituted, by the intermediate node by the leakage current signal on each phase transmission line of electricity
Supervisory control of substation terminal is sent to, the supervisory control of substation terminal is transferred to the remote monitoring center by fiber optic network.
Insulator leakage current comprising can as feature periodic component and aperiodic component, reservation is should give during denoising.
Fast Fourier Transform (FFT) (FFT) can extract the periodic component of leakage current, and then component performance period and aperiodic component
Separation.Arbitrarily complicated signal decomposition adaptively can be had actual physics meaning by intrinsic time Scale Decomposition (ITD) to be some
The intrinsic rotational component PRC (Proper Rotation Component) of justice and a monotonic trend (surplus).
Further, the aperiodic component of the leakage current signal and the mistake of periodic component are separated by Fourier transform
Journey is as follows：
The leakage current signal is expressed as：
X (n)=s (n)+e (n)+g (n)+h (n)；
Wherein, n=1,2 ..., N；N is the length of discrete signal, and s is the discrete periodic component in leakage current signal；e
For natural period frequency noise；G is discrete white noise；H abrupt local values caused by electric discharge；
Threshold value T is separated by setting onec' separation g (n) and h (n)；The Tc' acquisition is calculated by below equation：
Tc'=c × thr × σ '；
σ '=median | X (n) |/0.6745；
Wherein, median is that statement takes median；σ ' is the variance of white noise；C is the regulation of controlling cycle component number
The factor；Thr is the fixed threshold function of white noise,K is signal length；X (n) is leakage current signal x (n)
Fourier coefficient；
By in the periodic component of the leakage current signal, the primitive period periodic component consistent with voltage cycle is protected
Stay, and remove the natural period frequency noise of the periodic component, the periodic component of reservation is transformed into time domain, protected
The time-domain representation for the periodic component stayed.
Wherein, note NUM (Tc') it is to take threshold value TcAmplitude in the periodic component that ' when isolates from amplitude spectrum for 0
Number, as NUM (Tc')=100 when, can preferably obtain leakage current signal X (n) aperiodic component and periodic component.
Wherein, e (n) is obvious non-fundametal compoment in the insulator leakage current under drying regime.Under drying regime
The insulator leakage current signal of collection mainly contains fundametal compoment, and harmonic wave point occurs in contaminated insulator under moist cup border
Amount, therefore, obvious non-fundametal compoment is disturbed as intrinsic frequency in the insulator leakage current under desirable drying regime, and according to
This does truncation to gathering leakage current under wet environment, to eliminate interference.
By the aperiodic component by Fourier transform, the time-domain representation of the aperiodic component is obtained.
Further, the process of the noise of passage time Scale Decomposition removal aperiodic component is：
By the aperiodic component by Fourier transform, the time-domain representation of the aperiodic component is obtained；Using described
Existing similar waveform section carries out continuation to the two ends of the aperiodic component in leakage current signal；
Insulator flashover from making moist to occurring will undergo certain process, leakage current shown as on waveform it is interim because
This, it is believed that leakage current has similitude on partial waveform.
Specifically, during continuation, the similarity degree of waveform segment is characterized using Euclidean distance, it is public by taking left continuation as an example
Formula is as follows：
Wherein, i and l is isometric different wave section, and l is signal high order end one piece of data, and i is the hop count in signal
According to；Length (l) represents waveform segment l length.The corresponding i of minimum value in all dt is selected, and remembers the most like ripple that it is l
Shape section.The long waveform segments of the length (i) on the left of the i are taken to carry out continuation to the left end of primary signal.Because ITD enters according to extreme value
Row is decomposed, and leakage current comprises at least fundamental signal, in order to ensure that the data that continuation comes out comprise at least an extreme point, is prolonged
Open up and take length (l)=length (i)=primitive period length/2.
Aperiodic component progress time scale decomposition to the leakage current after continuation obtains several intrinsic rotations
Component PRCiWith a monotonic trend (surplus)；
Pass through the PRC to NoiseiNoise-removed threshold value T is seti, and to each PRCiCarried out by soft-threshold or hard -threshold
Quantify；
The TiCalculated and obtained by below equation：
Ti=thri×σi；
Wherein, fixed threshold functionNiFor PRCiLength；σi=median | PRCi|/0.6745,
Represent PRCiThe estimate of noise variance；
It is as follows that the quantization of the soft-threshold and the hard -threshold removes expressions of noise difference：
Wherein, PRCi,jIt is PRCiIn j-th value；
To each PRC after quantizationiIt is reconstructed with surplus, obtains aperiodic point of the leakage current after denoising
Amount.Reconstruct refers to each PRCiAnd surplus, the component of signal that these aperiodic components are further decomposed synthesizes one again
The aperiodic component of leakage current；Reconstruct is the reverse process of signal decomposition.
Based on on the one hand conception, another aspect of the present invention exists there is provided a kind of electric transmission line isolator leakage current
Line monitoring system, including sensor node, intermediate node and remote monitoring center, the sensor node is arranged on each defeated
On each insulator of electric line, the leakage current signal on the insulator is obtained in real time；On the transmission line of electricity of each phase
The sensor node is communicated by ZigBee wireless communication protocols with the intermediate node, will be each by the intermediate node
The leakage current signal on phase transmission line of electricity is sent to supervisory control of substation terminal, and the supervisory control of substation terminal passes through optical fiber
Network transmission is to the remote monitoring center；
The remote monitoring center is used to receive and store the leakage current signal, and separates institute by Fourier transform
The aperiodic component and periodic component of leakage current signal are stated, the intrinsic frequency interference in the periodic component is removed, and pass through
Time scale decomposes the noise for removing aperiodic component, then by the aperiodic component after denoising and the periodic component weight
Leakage current signal described in structure；When the leakage current signal is more than default leakage current threshold value, the remote monitoring center
Send alarm.
Further, temperature sensor, humidity sensor are also included on the sensor node, for obtaining transmission line of electricity
The temperature of upper each insulator surface, humidity data；Obtained simultaneously by an atmosphere particulate matter monitoring instrument near the insulator
Atmospheric particulates (APM) index；The remote monitoring center is referred to by the temperature, the humidity, the Atmospheric particulates
Count and generate corresponding leakage current signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve, let out described in acquisition
Leakage current signal and the temperature, the humidity, the relation property of the Atmospheric particulates.
Further, the electric current inductive pick-up on the sensor node includes loop coil, with the loop coil
Winding connection I-V change-over circuits, the I-V change-over circuits are made up of a transport and placing device.
Further, the temperature sensor, humidity sensor are that SAW humidity sensors label and SAW temperature are passed respectively
Sensor label, the SAW humidity sensors label and the SAW temperature sensor label are sticked on the insulator, pass through
One reader obtains the temperature and humidity data of the insulator, the temperature and humidity measurement of the reader and the sensor node
Circuit is connected.
The inventive method has the following advantages that：
The electric transmission line isolator On-line Monitoring of Leakage Current method and its system of the present invention, it is real-time by current sensor
The leakage current signal on insulator is obtained, leakage current signal and Surveillance center are then realized by cordless communication network
Data communication, then decomposes to carry out denoising to leakage current signal, can obtain by Fourier transform and time scale
Accurate leakage current signal is obtained, based on leakage current signal, the running status of insulator can in real time be monitored,
And predict that the accident conditions such as pollution flashover occur for insulator.
Brief description of the drawings
A kind of electric transmission line isolator On-line Monitoring of Leakage Current method flow block diagram of Fig. 1 embodiment of the present invention.
A kind of electric transmission line isolator On-line Monitoring of Leakage Current system architecture connection figure of Fig. 2 embodiment of the present invention.
The sensor node system structured flowchart of Fig. 3 embodiment of the present invention.
The electric current inductive pick-up electrical block diagram of Fig. 4 embodiment of the present invention.
The electric current inductive pick-up equivalent circuit schematic of Fig. 5 embodiment of the present invention.
The Temperature and Humidity Sensor System structure principle chart that Fig. 6 present invention is implemented.
Embodiment
Following examples are used to illustrate the present invention, but are not limited to the scope of the present invention.
Embodiment 1
As shown in figure 1, the invention provides a kind of electric transmission line isolator On-line Monitoring of Leakage Current method.Specifically,
This method comprises the following steps：
S101, the leakage current signal for obtaining each insulator on transmission line of electricity in real time, by cordless communication network by institute
State leakage current signal and be sent to remote monitoring center；
S102, the remote monitoring center receive and store the leakage current signal, and are separated by Fourier transform
The aperiodic component and periodic component of the leakage current signal, remove the intrinsic frequency interference in the periodic component, and lead to
The noise that time Scale Decomposition removes aperiodic component is crossed, then by the aperiodic component and the periodic component after denoising
Reconstruct the leakage current signal；
S103, when the leakage current signal is more than default leakage current threshold value, the remote monitoring center sends report
Alert prompting.
Wherein, the electric transmission line isolator On-line Monitoring of Leakage Current method also includes：Obtain in real time on transmission line of electricity
Atmospheric particulates (APM) index near the temperature of each insulator surface, humidity data, and the insulator, and will be logical
Cross cordless communication network and be sent to the remote monitoring center.
Wherein, the remote monitoring center is given birth to according to the leakage current signal, temperature, humidity, Atmospheric particulates index
Into corresponding leakage current signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve, the leakage electricity is obtained
Flow signal and the temperature, the humidity, the relation property of the Atmospheric particulates.
Wherein, the cordless communication network passes through ZigBee channel radios by the sensor node of multiple settings on the insulator
Believe that agreement is constituted with intermediate node, transmitted the leakage current signal on each phase transmission line of electricity by the intermediate node
To supervisory control of substation terminal, the supervisory control of substation terminal is transferred to the remote monitoring center by fiber optic network.
Insulator leakage current comprising can as feature periodic component and aperiodic component, reservation is should give during denoising.
Fast Fourier Transform (FFT) (FFT) can extract the periodic component of leakage current, and then component performance period and aperiodic component
Separation.Arbitrarily complicated signal decomposition adaptively can be had actual physics meaning by intrinsic time Scale Decomposition (ITD) to be some
The intrinsic rotational component PRC (Proper Rotation Component) of justice and a monotonic trend (surplus).
Wherein, by Fourier transform separate the leakage current signal aperiodic component and periodic component process such as
Under：
The leakage current signal is expressed as：
X (n)=s (n)+e (n)+g (n)+h (n)；
Wherein, n=1,2 ..., N；N is the length of discrete signal, and s is the discrete periodic component in leakage current signal；e
For natural period frequency noise；G is discrete white noise；H abrupt local values caused by electric discharge；
Threshold value T is separated by setting onec' separation g (n) and h (n)；The Tc' acquisition is calculated by below equation：
Tc'=c × thr × σ '；
σ '=median | X (n) |/0.6745；
Wherein, median is that statement takes median；σ ' is the variance of white noise；C is the regulation of controlling cycle component number
The factor；Thr is the fixed threshold function of white noise,K is signal length；X (n) is leakage current signal x (n)
Fourier coefficient；
By in the periodic component of the leakage current signal, the primitive period periodic component consistent with voltage cycle is protected
Stay, and remove the natural period frequency noise of the periodic component, the periodic component of reservation is transformed into time domain, protected
The time-domain representation for the periodic component stayed.
Wherein, note NUM (Tc') it is to take threshold value TcAmplitude in the periodic component that ' when isolates from amplitude spectrum for 0
Number, as NUM (Tc')=100 when, can preferably obtain leakage current signal X (n) aperiodic component and periodic component.
Wherein, e (n) is obvious non-fundametal compoment in the insulator leakage current under drying regime.Under drying regime
The insulator leakage current signal of collection mainly contains fundametal compoment, and harmonic wave point occurs in contaminated insulator under moist cup border
Amount, therefore, obvious non-fundametal compoment is disturbed as intrinsic frequency in the insulator leakage current under desirable drying regime, and according to
This does truncation to gathering leakage current under wet environment, to eliminate interference.
By the aperiodic component by Fourier transform, the time-domain representation of the aperiodic component is obtained.
Wherein, the process of the noise of passage time Scale Decomposition removal aperiodic component is：
By the aperiodic component by Fourier transform, the time-domain representation of the aperiodic component is obtained；Using described
Existing similar waveform section carries out continuation to the two ends of the aperiodic component in leakage current signal；
Insulator flashover from making moist to occurring will undergo certain process, leakage current shown as on waveform it is interim because
This, it is believed that leakage current has similitude on partial waveform.
Specifically, during continuation, the similarity degree of waveform segment is characterized using Euclidean distance, it is public by taking left continuation as an example
Formula is as follows：
Wherein, i and l is isometric different wave section, and l is signal high order end one piece of data, and i is the hop count in signal
According to；Length (l) represents waveform segment l length.The corresponding i of minimum value in all dt is selected, and remembers the most like ripple that it is l
Shape section.The long waveform segments of the length (i) on the left of the i are taken to carry out continuation to the left end of primary signal.Because ITD enters according to extreme value
Row is decomposed, and leakage current comprises at least fundamental signal, in order to ensure that the data that continuation comes out comprise at least an extreme point, is prolonged
Open up and take length (l)=length (i)=primitive period length/2.
Aperiodic component progress time scale decomposition to the leakage current after continuation obtains several intrinsic rotations
Component PRCiWith a monotonic trend (surplus)；
Pass through the PRC to NoiseiNoise-removed threshold value T is seti, and to each PRCiCarried out by soft-threshold or hard -threshold
Quantify；
The TiCalculated and obtained by below equation：
Ti=thri×σi；
Wherein, fixed threshold functionNiFor PRCiLength；σi=median | PRCi|/0.6745,
Represent PRCiThe estimate of noise variance；
It is as follows that the quantization of the soft-threshold and the hard -threshold removes expressions of noise difference：
Wherein, PRCi,jIt is PRCiIn j-th value；
To each PRC after quantizationiIt is reconstructed with surplus, obtains aperiodic point of the leakage current after denoising
Amount.
Embodiment 2
Based on same inventive concept, another aspect of the present invention, there is provided a kind of electric transmission line isolator as shown in Figure 2
On-line Monitoring of Leakage Current system, including sensor node, intermediate node and remote monitoring center, the sensor node are set
Put on each insulator of each transmission line of electricity, the leakage current signal on the insulator is obtained in real time；Each phase it is defeated
The sensor node in electric line is communicated by ZigBee wireless communication protocols with the intermediate node, passes through the centre
Leakage current signal on each phase transmission line of electricity is sent to supervisory control of substation terminal by node, and the supervisory control of substation terminal is led to
Cross fiber optic network and be transferred to the remote monitoring center；
The remote monitoring center is used to receive and store the leakage current signal, and separates institute by Fourier transform
The aperiodic component and periodic component of leakage current signal are stated, the intrinsic frequency interference in the periodic component is removed, and pass through
Time scale decomposes the noise for removing aperiodic component, then by the aperiodic component after denoising and the periodic component weight
Leakage current signal described in structure；When the leakage current signal is more than default leakage current threshold value, the remote monitoring center
Send alarm.
As shown in figure 3, also including temperature sensor, humidity sensor on the sensor node, for obtaining power transmission line
The temperature of each insulator surface, humidity data on road；The insulator is obtained by an atmosphere particulate matter monitoring instrument simultaneously attached
Near Atmospheric particulates (APM) index；The remote monitoring center is generated by the temperature, humidity, Atmospheric particulates index
Corresponding leakage current signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve, obtain the leakage current
Signal and the temperature, the humidity, the relation property of the Atmospheric particulates.
As shown in Figure 4,5, the electric current inductive pick-up on the sensor node includes loop coil, with the toroid
The I-V change-over circuits of the winding connection of circle, the I-V change-over circuits are made up of a transport and placing device.
Existing electric current inductive pick-up is Rogowski coil, and weak point is that the data of measurement are influenceed by high-intensity magnetic field,
Easily produce error, can with frequency range it is narrow, it is not easy to realize the measurement of low-frequency band, and the precision of current sensor
Influenceed etc. performance by manufacture material than larger.The electric current inductive pick-up of the present invention adds the response to the faint stream of front end electricity
Scope, accelerates the speed of reaction.The frequency characteristic of electric current inductive pick-up of the present invention is：
Wherein, RfFor amplifier feedback resistance；RinFor amplifier input resistance (being ideally 0), obtained by above-mentioned formula
The bound cut-off frequency of electric current inductive pick-up of the present invention is respectively；
Upper cut-off frequency：
Upper cut-off frequency：
Wherein, amplifier constitutes I-V circuits, by adjusting RfOutput voltage V can be conveniently adjustedOSize, while not influenceing
Sensor amplitude versus frequency characte.I-V circuits (current-voltage conversion circuit) the input impedance R constituted due to amplifierinIt is minimum, in formula
The low frequency for stating formula visible light transducer obtains very big extension, while minimum RinWith the equivalent stray capacitance C of punching coilsMutually simultaneously
Connection so that CsBypass effect substantially reduce, then the high frequency of sensor also obtains very big extension.The self-induction L of punching coils,
Have just comparable with amplifier input impedance when frequency is very low, this allows for sensor and does not require that the excessive number of turn is ensured that
Less low-frequency minimum, so as to understand that coil turn takes 100 circles or so both to ensure higher sensitivity, is ensured that wider
Passband, while so that sensor external shield is very easy to.Minimum RinAlso so that magnetic core magnetic hydraulic performance decline, to sensor
Influence is substantially reduced, and this reduces the requirement to magnetic core so that the cost of sensor is substantially reduced, while sensor is out of doors
The performance of long-term use, which changes with time, to be greatly reduced.
Passed as shown in fig. 6, the temperature sensor, humidity sensor are SAW humidity sensors label and SAW temperature respectively
Sensor label, the SAW humidity sensors label and the SAW temperature sensor label are sticked on the insulator, pass through
One reader obtains the temperature and humidity data of the insulator, the temperature and humidity measurement of the reader and the sensor node
Circuit is connected.
Although above with general explanation and specific embodiment, the present invention is described in detail, at this
On the basis of invention, it can be made some modifications or improvements, this will be apparent to those skilled in the art.Therefore,
These modifications or improvements, belong to the scope of protection of present invention without departing from theon the basis of the spirit of the present invention.
Claims (10)
1. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method, it is characterised in that methods described comprises the following steps：
The leakage current signal of each insulator on transmission line of electricity is obtained in real time, by cordless communication network by the leakage current
Signal is sent to remote monitoring center；
The remote monitoring center receives and stores the leakage current signal, and separates the leakage electricity by Fourier transform
The aperiodic component and periodic component of signal are flowed, the intrinsic frequency interference in the periodic component, and passage time yardstick is removed
The noise for removing aperiodic component is decomposed, then will be let out described in the aperiodic component after denoising and periodic component reconstruct
Leakage current signal；
When the leakage current signal is more than default leakage current threshold value, the remote monitoring center sends alarm.
2. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method according to claim 1, it is characterised in that institute
Stating electric transmission line isolator On-line Monitoring of Leakage Current method also includes：Each insulator surface on transmission line of electricity is obtained in real time
Atmospheric particulates index near temperature, humidity data, and the insulator, and institute will be sent to by cordless communication network
State remote monitoring center.
3. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method according to claim 2, it is characterised in that institute
State remote monitoring center and corresponding leakage current is generated according to the leakage current signal, temperature, humidity, Atmospheric particulates index
Signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve, obtain the leakage current signal and the temperature
Degree, humidity, the relation property of Atmospheric particulates.
4. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method according to claim 1, it is characterised in that institute
State cordless communication network and ZigBee wireless communication protocols and middle node are passed through by the sensor node of multiple settings on the insulator
Point composition, supervisory control of substation end is sent to by the intermediate node by the leakage current signal on each phase transmission line of electricity
End, the supervisory control of substation terminal is transferred to the remote monitoring center by fiber optic network.
5. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method according to claim 1, it is characterised in that logical
Cross Fourier transform separate the leakage current signal aperiodic component and periodic component process it is as follows：
The leakage current signal is expressed as：
X (n)=s (n)+e (n)+g (n)+h (n)；
Wherein, n=1,2 ..., N；N is the length of discrete signal, and s is the discrete periodic component in leakage current signal；E is solid
There is period frequency noise；G is discrete white noise；H abrupt local values caused by electric discharge；
Threshold value T is separated by setting onec' separation g (n) and h (n)；The Tc' acquisition is calculated by below equation：
Tc'=c × thr × σ '；
σ '=median | X (n) |/0.6745；
Wherein, median is that statement takes median；σ ' is the variance of white noise；C is the regulatory factor of controlling cycle component number；
Thr is the fixed threshold function of white noise,K is signal length；X (n) is leakage current signal x (n) Fu
Vertical leaf system number；
By in the periodic component of the leakage current signal, the primitive period periodic component consistent with voltage cycle retains,
And the natural period frequency noise of the periodic component is removed, the periodic component of reservation is transformed into time domain, retained
The periodic component time-domain representation.
6. a kind of electric transmission line isolator On-line Monitoring of Leakage Current method according to claim 1, it is characterised in that logical
Cross time Scale Decomposition and remove the process of noise of aperiodic component and be：
By the aperiodic component by Fourier transform, the time-domain representation of the aperiodic component is obtained；Utilize the leakage
Existing similar waveform section carries out continuation to the two ends of the aperiodic component in current signal；
Aperiodic component progress time scale decomposition to the leakage current after continuation obtains several intrinsic rotational components
PRCiWith a surplus；
Pass through the PRC to NoiseiNoise-removed threshold value T is seti, and to each PRCiQuantified by soft-threshold or hard -threshold；
The TiCalculated and obtained by below equation：
Ti=thri×σi；
Wherein, fixed threshold functionNiFor PRCiLength；σi=median | PRCi|/0.6745, represent
PRCiThe estimate of noise variance；
It is as follows that the quantization of the soft-threshold and the hard -threshold removes expressions of noise difference：
<mrow>
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<msub>
<mi>PRC</mi>
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<mi>PRC</mi>
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<mi>PRC</mi>
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<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
</mrow>
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Wherein, PRCi,jIt is PRCiIn j-th value；
To each PRC after quantizationiIt is reconstructed with surplus, obtains the aperiodic component of the leakage current after denoising.
7. a kind of electric transmission line isolator On-line Monitoring of Leakage Current system, it is characterised in that including sensor node, middle node
Point and remote monitoring center, the sensor node are arranged on each insulator of each transmission line of electricity, and institute is obtained in real time
State the leakage current signal on insulator；The sensor node on the transmission line of electricity of each phase passes through ZigBee radio communications
Agreement communicates with the intermediate node, is passed the leakage current signal on each phase transmission line of electricity by the intermediate node
Supervisory control of substation terminal is sent to, the supervisory control of substation terminal is transferred to the remote monitoring center by fiber optic network；
The remote monitoring center is used to receive and store the leakage current signal, and by being let out described in Fourier transform separation
The aperiodic component and periodic component of leakage current signal, remove the intrinsic frequency interference in the periodic component, and passage time
Scale Decomposition removes the noise of aperiodic component, and the aperiodic component after denoising and the periodic component then are reconstructed into institute
State leakage current signal；When the leakage current signal is more than default leakage current threshold value, the remote monitoring center is sent
Alarm.
8. a kind of electric transmission line isolator On-line Monitoring of Leakage Current system according to claim 7, it is characterised in that institute
Stating also includes temperature sensor, humidity sensor on sensor node, for obtaining each insulator surface on transmission line of electricity
Temperature, humidity data；The Atmospheric particulates (APM) obtained simultaneously by an atmosphere particulate matter monitoring instrument near the insulator refer to
Number；The remote monitoring center generates corresponding leakage current by the temperature, the humidity, the Atmospheric particulates index
Signal curve, temperature curve, moisture curve and Atmospheric particulates exponential curve, obtain the leakage current signal and the temperature
Degree, the humidity, the relation property of the Atmospheric particulates.
9. a kind of electric transmission line isolator On-line Monitoring of Leakage Current system according to claim 7, it is characterised in that institute
The electric current inductive pick-up stated on sensor node includes loop coil, the I-V conversions being connected with the winding of the loop coil
Circuit, the I-V change-over circuits are made up of a transport and placing device.
10. a kind of electric transmission line isolator On-line Monitoring of Leakage Current system according to claim 7, it is characterised in that
The temperature sensor, humidity sensor are SAW humidity sensors label and SAW temperature sensor label respectively, and the SAW is wet
Degree sensor tag and the SAW temperature sensor label are sticked on the insulator, obtain described exhausted by a reader
The temperature and humidity data of edge, the reader is connected with the temperature and humidity measurement circuit of the sensor node.
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| CN111162506B (en) * | 2020-01-13 | 2022-02-18 | 华电国际电力股份有限公司邹县发电厂 | Double-speed motor protection measurement and control device |
| CN116990718A (en) * | 2023-08-22 | 2023-11-03 | 北京中联太信科技有限公司 | Method for detecting medium-high voltage online micro alternating current leakage |
| CN116990718B (en) * | 2023-08-22 | 2024-01-26 | 北京中联太信科技有限公司 | Method for detecting medium-high voltage online micro alternating current leakage |
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