CN106066437A - A kind of on-line monitoring device of metallic oxide arrester and monitoring method thereof - Google Patents

Abstract

The invention discloses a kind of on-line monitoring device of metallic oxide arrester and monitoring method thereof, including: main control chip, gather leakage current signal and the data acquisition module of voltage signal, receive the data of data acquisition module and calculate current in resistance property and be sent to the backstage algorithm processing module of main control chip, being connected to the man-machine interaction assembly of main control chip alternately；Data acquisition module includes: be used for measuring the voltage and current measurement module of the Leakage Current of the voltage at metal oxide arrester spark gap two ends and metal oxide arrester spark gap, receive the signal of voltage and current measurement module and carry out the filtration module of Filtering Processing, the signal of the module that accepts filter the AD conversion module being AD converted.The present invention provides a kind of on-line monitoring device of metallic oxide arrester and monitoring method thereof, the present invention takes into full account the impact that current in resistance property is extracted by the harmonic wave in voltage, interference current in resistance property extracted due to harmonic voltage can well be reduced, improve efficiency and the accuracy of on-line monitoring.

Description

A kind of on-line monitoring device of metallic oxide arrester and monitoring method thereof

Technical field

The present invention relates to electrical equipment technical field of measurement and test, particularly a kind of on-line monitoring device of metallic oxide arrester And monitoring method.

Background technology

It is excellent that metal oxide arrester spark gap (MOA) has that nonlinear characteristic is good, through-current capacity is big, protective value is superior etc. Good characteristic, is the main device of relay protection of power system.MOA works online adversely thermal damaged, transient state, humorous state overvoltage for a long time The impact of the factors such as impact and internal humidity, accelerates the aging deterioration of metal oxide arrester spark gap, causes spark gap Damage, finally make spark gap lose protective effect.Therefore being monitored operating spark gap is that power system security is reliable The important guarantee run.Both at home and abroad many achievements in research are pointed out, MOA is aging, internal wetted and insulating properties bad time, leakage Electric current can increase, and wherein resistive current component increases substantially, and therefore current in resistance property is the important ginseng of monitoring spark gap running status Amount.

Classical capacitive current compensation method can not remove the harmonic component in capacity current, and such harmonic component can be mixed into In current in resistance property, causing the current in resistance property of this algorithm to produce error, thus affect the extraction accuracy of current in resistance property, it is right to easily cause The erroneous judgement of state of metal oxide lightning arrester.

Summary of the invention

For solving the deficiencies in the prior art, it is an object of the invention to provide a kind of metal oxide arrester on-line monitoring Device and monitoring method thereof, the present invention takes into full account the impact that current in resistance property is extracted by the harmonic wave in voltage, can well subtract The little interference extracted current in resistance property due to harmonic voltage, improves efficiency and the accuracy of on-line monitoring.

In order to realize above-mentioned target, the present invention adopts the following technical scheme that:

A kind of on-line monitoring device of metallic oxide arrester, including: main control chip, gather leakage current signal and voltage The data acquisition module of signal, receives the data of data acquisition module and calculates current in resistance property and be sent to the backstage of main control chip Algorithm processing module, is connected to the man-machine interaction assembly of main control chip alternately；Data acquisition module includes: be used for measuring metal oxygen The voltage at compound spark gap spark gap two ends and the voltage and current measurement of the Leakage Current of metal oxide arrester spark gap Module, receives the signal of voltage and current measurement module and carries out the filtration module of Filtering Processing, and the signal of the module that accepts filter is also The AD conversion module being AD converted.

Aforesaid a kind of on-line monitoring device of metallic oxide arrester, man-machine interaction assembly composition has: be connected to master control The GPRS module of chip, is connected to the PC of GPRS module, is connected to the display module of PC.

Aforesaid a kind of on-line monitoring device of metallic oxide arrester, backstage algorithm processing module includes: voltage signal Read module, for voltage signal carries out the phase shifter of 90 ° of phase shifts, receives and detects the next voltage signal of phase shifter transmission Waveshape detector, for the voltage signal read is carried out fft analysis FFT module, leakage current read module, is connected to voltage Signal reading module, the zero-crossing detector of leakage current read module, be connected to FFT module and zero-crossing detector and calculate crystalline substance Dielectric capacitance C and G, C computing module of capacitance compensation coefficient G, be connected to waveshape detector and the multiplier of G, C computing module, It is connected to multiplier and the subtractor of Leakage Current module.

The monitoring method of aforesaid a kind of on-line monitoring device of metallic oxide arrester comprises the steps:

(1) the initial voltage u and initial leakage current i of metal oxide arrester spark gap are obtained_x；

(2) initial voltage signal is carried out fft analysis, obtain fundamental voltage amplitude u₁, 3 subharmonic voltage amplitudes u₃And Frequency w；

(3) by initial voltage and Leakage Current by zero-crossing detector, finding initial voltage is leakage corresponding to zero moment Electric current i_x(t₀)；

(4) by step 2, fundamental voltage amplitude u obtained by 3₁, 3 subharmonic voltage amplitudes u₃, frequency w, leakage current i_x (t₀) bring formula (1) into and obtain brilliant dielectric capacitance C,

$c=\frac{i_x\left(t_0\right)}{{\mathrm{wu}}_1+3{\mathrm{wu}}_3}---\left(1\right)$

(5) by step 2, fundamental voltage amplitude u obtained by 4₁, 3 subharmonic voltage amplitudes u₃, frequency w, brilliant dielectric capacitance C Bring formula (2) into and obtain capacitance compensation coefficient G,

$G=\frac{{\mathrm{wcu}}_1^2+3{\mathrm{wcu}}_3^2}{u_1^2+u_3^2}---\left(2\right)$

(6) by initial voltage signal by phase shifter phase shift counterclockwise 90 °, the voltage after phase shift is obtained by waveforms detection u_sf；

(7) by step 5, capacitance compensation coefficient G, voltage u obtained by 6_sfIt is multiplied by multiplier；

(8) by the leakage current i acquired in step 1_xAnd the result obtained by step 7 subtracted each other by subtractor, obtain Resistive current component i_R；

(9) by the resistive current component i obtained by step 8_RIt is uploaded to main control chip, by main control chip by data transmission To display module and GPRS module；

(10) data obtained by step 9 are sent to PC by GPRS module.

The invention have benefit that: the present invention provides a kind of on-line monitoring device of metallic oxide arrester and prison thereof Survey method, it is possible to achieve the on-line real time monitoring to metal oxide arrester, the method for the present invention considers harmonic wave electricity simultaneously The pressure impact on capacitive current compensation method, can well reduce the interference extracted current in resistance property due to harmonic voltage, improves The accuracy extracted, thus reduce owing to harmonic wave disturbs the erroneous judgement to metal oxide arrester practical situation caused, dress Put structural principle simple, method simple possible, actual monitoring has the highest practical value, cost-effective, economical and efficient.

Accompanying drawing explanation

Fig. 1 is the structural representation of an embodiment of the present invention；

Fig. 2 is the schematic diagram of backstage of the present invention a kind of embodiment of algorithm processing module；

Fig. 3 is the equivalent model figure of an embodiment of the present invention；

Fig. 4 is that the present invention extracts current in resistance property and actual current in resistance property contrast effect figure；

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention made concrete introduction.

A kind of on-line monitoring device of metallic oxide arrester, including: main control chip, gather leakage current signal and voltage The data acquisition module of signal, receives the data of data acquisition module and calculates current in resistance property and be sent to the backstage of main control chip Algorithm processing module, is connected to the man-machine interaction assembly of main control chip alternately；Data acquisition module includes: be used for measuring metal oxygen The voltage at compound spark gap spark gap two ends and the voltage and current measurement of the Leakage Current of metal oxide arrester spark gap Module, receives the signal of voltage and current measurement module and carries out the filtration module of Filtering Processing, and the signal of the module that accepts filter is also The AD conversion module being AD converted.

Man-machine interaction assembly composition has: is connected to the GPRS module of main control chip, is connected to the PC of GPRS module, connects Display module in PC.

Backstage algorithm processing module includes: voltage signal read module, for voltage signal carries out the phase shift of 90 ° of phase shifts Device, receives and detects the waveshape detector of the voltage signal that phase shifter transmission comes, divide for the voltage signal read is carried out FFT Analysis FFT module, leakage current read module, it is connected to voltage signal read module, the zero passage detection of leakage current read module Device, is connected to FFT module and zero-crossing detector and calculates brilliant dielectric capacitance C and G, C computing module of capacitance compensation coefficient G, It is connected to waveshape detector and the multiplier of G, C computing module, is connected to multiplier and the subtractor of Leakage Current module.Backstage The operating procedure of algorithm processing module is: first passes through voltage x current read module and reads the voltage in main control chip and reveal electricity Stream, then the voltage signal read is carried out fft analysis by FFT module, then by zero-crossing detector to the voltage of reading, leakage Electric current carries out the i that zero passage detection obtains_x(t₀)、w、u₁、u₃, G, C module i obtained_x(t₀)、w、u₁、u₃Calculate brilliant dielectric capacitance C, capacitance compensation coefficient G；Phase shifter carries out 90 ° of phase shifts, the voltage signal after waveshape detector detection phase shift to voltage signal, makes With multiplier, the voltage after phase shift is multiplied with G；Subtractor is used to be subtracted each other with phase shifter acquired results by Leakage Current, thus To current in resistance property.

The method of the present invention considers the harmonic voltage impact on capacitive current compensation method, can well reduce due to humorous The interference that current in resistance property is extracted by wave voltage, improves the accuracy of extraction, thus reduce due to harmonic wave interference cause to gold Belong to the erroneous judgement of Oxide Arrester practical situation；The monitoring method of on-line monitoring device of metallic oxide arrester includes walking as follows Rapid:

(1) the initial voltage u and initial leakage current i of metal oxide arrester spark gap are obtained_x；

(2) initial voltage signal is carried out fft analysis, obtain fundamental voltage amplitude u₁, 3 subharmonic voltage amplitudes u₃And Frequency w；

(3) by initial voltage and Leakage Current by zero-crossing detector, finding initial voltage is leakage corresponding to zero moment Electric current i_x(t₀)；

(4) by step 2, fundamental voltage amplitude u obtained by 3₁, 3 subharmonic voltage amplitudes u₃, frequency w, leakage current i_x (t₀) bring formula (1) into and obtain brilliant dielectric capacitance C,

$c=\frac{i_x\left(t_0\right)}{{\mathrm{wu}}_1+3{\mathrm{wu}}_3}---\left(1\right)$

(5) by step 2, fundamental voltage amplitude u obtained by 4₁, 3 subharmonic voltage amplitudes u₃, frequency w, brilliant dielectric capacitance C Bring formula (2) into and obtain capacitance compensation coefficient G,

$G=\frac{{\mathrm{wcu}}_1^2+3{\mathrm{wcu}}_3^2}{u_1^2+u_3^2}---\left(2\right)$

(6) by initial voltage signal by phase shifter phase shift counterclockwise 90 °, the voltage after phase shift is obtained by waveforms detection u_sf；

(7) by step 5, capacitance compensation coefficient G, voltage u obtained by 6_sfIt is multiplied by multiplier；

(8) by the leakage current i acquired in step 1_xAnd the result obtained by step 7 subtracted each other by subtractor, obtain Resistive current component i_R；

(9) by the resistive current component i obtained by step 8_RIt is uploaded to main control chip, by main control chip by data transmission To display module and GPRS module；

(10) data obtained by step 9 are sent to PC by GPRS module.

It should be understood that the pushing away of formula (1) (2) in the monitoring method of on-line monitoring device of metallic oxide arrester The process of leading is: metal oxide arrester, when normally working, flows through the power current within spark gap the least, at spark gap In small area analysis district.In small area analysis district, MOA model can be equivalent to simplifiedly as described in Figure 3 by electric capacity and nonlinear resistance also The model of connection.In Fig. 3, i_xFor leakage current of an arrester, i_RThe current in resistance property produced for nonlinear resistance, i_cProduce for electric capacity and hold Property electric current, u is the voltage at spark gap two ends.Leakage current of an arrester i_xFor current in resistance property i_RWith capacity current i_cSum.

Classical capacitive current compensation method principle is to will leak out electric current i_xIn capacitive current component i_cCompensation is fallen, thus To current in resistance property i_R, its principle can use formula (3) to represent:

${\∫}_0^{2\mathrm{\π}}{u}_{sf}(i_x-{\mathrm{Gu}}_{sf})d\left(wt\right)=0---\left(3\right)$

When capacitive current compensation falls, i_x-Gu_sfIt is current in resistance property, can obtain

i_R=i_x-Gu_sf (4)

If containing 3 subharmonic voltages in electrical network, acting on the voltage on MOA can be expressed as:

U=u₁sin(wt)+u₃sin(3wt) (5)

u₁And u₃It is respectively first-harmonic and the amplitude of 3 subharmonic.

Capacity current is:

$i_c=c\frac{du}{dt}={\mathrm{wcu}}_1\cos wt+3{\mathrm{wcu}}_{3}cos3wt---\left(6\right)$

Current in resistance property is:

i_R=I_R1sinwt+I_R3sin3wt (7)

I_R1And I_R3It is respectively fundamental current and the 3 subharmonic current amplitudes of MOA current in resistance property.

(5), (6), (7) are substituted into (3) formula, can be in the hope of penalty coefficient G:

$G=\frac{{\mathrm{wcu}}_1^2+3{\mathrm{wcu}}_3^2}{u_1^2+u_3^2}---\left(8\right)$

Now, by the current in resistance property value under the available harmonic voltage of formula (4),

$i_R=I_{R1}\sin wt+I_{R3}sin3wt+\frac{2{\mathrm{wcu}}_1^2{u}_{3}cos3wt}{u_1^2+u_3^2}-\frac{2{\mathrm{wcu}}_3^2{u}_1\cos wt}{u_1^2+u_3^2}---\left(9\right)$

By formula (9) compared with formula (7), it is known that after line voltage adds harmonic wave, the harmonic voltage meeting in electrical network On current in resistance property produce impact, it is contemplated that the penalty coefficient G of harmonic voltage can be seen that as shown in formula (8) not only with fundamental voltage About the most relevant with electric voltage frequency and 3 subharmonic voltage amplitudes.

When at the voltage zero-cross at spark gap two ends, flow through the current in resistance property i of spark gap_RIt is zero, then flows through spark gap Total current i_xEqual with the capacitive current component of arrester valve piece made of metallic oxide.When the voltage containing 3 subharmonic, electricity entirely Stream i_xCan be expressed as:

$i_x\left(t\right)=i_R\left(t\right)+c\frac{du}{dt}=i_R\left(t\right)+wc(u_1\cos wt+u_{3}cos3wt)---\left(10\right)$

Being located at the t0 moment, being carried in the take shelter from the thunder line voltage instantaneous value at two ends of metal-oxide is zero, now can be with voltage Can be expressed from the next:

u(t₀)=u₁sinwt₀+u₃sin3wt₀=0 (11)

Total current i that metal-oxide is lightning-arrest in the case of voltage zero-cross can be obtained further_x(t₀) value:

i_x(t₀)=i_R(t₀)+wc(u₁coswt₀+3u₃cos3wt₀) (12)

According to feature during voltage zero-cross, formula (12) metal oxide arrester valve in the case of voltage zero-cross can be obtained Brilliant dielectric capacitance on sheet:

$c=\frac{i_x\left(t_0\right)}{{\mathrm{wu}}_1+3{\mathrm{wu}}_3}---\left(13\right)$

Think constant due to what the brilliant dielectric appearance of MOA valve block can approximate, it can be considered that the electric capacity of formula (13) gained Value is the brilliant dielectric capacitance of MOA.

Formula (13) is brought in (8) formula and can obtain containing the penalty coefficient under voltage harmonic

And utilize formula (4) to try to achieve the current in resistance property value under harmonic voltage.

Effect contrast figure such as Fig. 4 institute of current in resistance property obtained by the method used by the present invention of use and actual current in resistance property Show.Fig. 4 shows, the current in resistance property that the present invention is extracted has the most consistent with the actual current in resistance property of metal oxide arrester Property, illustrate that this method can realize the on-line monitoring to metal oxide arrester well.Can be obtained by analysis chart 4, Total current and the current in resistance property numerical value of metal oxide arrester are relatively stable, and waveform has periodically and symmetry, meets The practical operation situation of MOA.The current in resistance property oscillogram major part region that actual current in resistance property in Fig. 4 extracts with context of methods More consistent, the current waveform extracted herein in the current over-zero moment has less shake, it may be possible to owing to containing in line voltage There is the impact of the therein harmonic wave that the nonlinear elements of a small amount of higher hamonic wave and metal oxide arrester self produces, The present invention is to simplify to calculate the impact that have ignored the less Electric Network Higher Harmonic of quantity, but total resistive curve conformity is higher, Meet the needs of actual monitoring process.

The present invention provides a kind of on-line monitoring device of metallic oxide arrester and monitoring method thereof, it is possible to achieve to metal The on-line real time monitoring of Oxide Arrester, the method for the present invention considers the harmonic voltage shadow to capacitive current compensation method simultaneously Ring, interference current in resistance property extracted due to harmonic voltage can well be reduced, improve the accuracy of extraction, thus reduce Owing to harmonic wave disturbs the erroneous judgement to metal oxide arrester practical situation caused, apparatus structure principle is simple, and method is simple Feasible, actual monitoring has the highest practical value, cost-effective, economical and efficient.

The ultimate principle of the present invention, principal character and advantage have more than been shown and described.The technical staff of the industry should Understanding, above-described embodiment limits the present invention the most in any form, and the mode of all employing equivalents or equivalent transformation is obtained Technical scheme, all falls within protection scope of the present invention.

Claims (4)

1. an on-line monitoring device of metallic oxide arrester, it is characterised in that including: main control chip, gathers leakage current Signal and the data acquisition module of voltage signal, receive the data of above-mentioned data acquisition module and calculate current in resistance property and be sent to The backstage algorithm processing module of above-mentioned main control chip, is connected to the man-machine interaction assembly of above-mentioned main control chip alternately；Above-mentioned data Acquisition module includes: voltage and metal oxide arrester for measuring metal oxide arrester spark gap two ends are taken shelter from the thunder The voltage and current measurement module of the Leakage Current of device, receives the signal of above-mentioned voltage and current measurement module and carries out Filtering Processing Filtration module,

The signal receiving above-mentioned filtration module the AD conversion module being AD converted.

A kind of on-line monitoring device of metallic oxide arrester the most according to claim 1, it is characterised in that above-mentioned man-machine Interactive component composition has: is connected to the GPRS module of above-mentioned main control chip, is connected to the PC of above-mentioned GPRS module, is connected to State the display module of PC.

A kind of on-line monitoring device of metallic oxide arrester the most according to claim 1, it is characterised in that above-mentioned backstage Algorithm processing module includes: voltage signal read module, for voltage signal carries out the phase shifter of 90 ° of phase shifts, receives and examines Survey the waveshape detector of the voltage signal that the transmission of above-mentioned phase shifter comes, for the voltage signal read is carried out fft analysis FFT mould Block, leakage current read module, it is connected to above-mentioned voltage signal read module, the zero-crossing detector of leakage current read module, It is connected to above-mentioned FFT module and zero-crossing detector and calculates brilliant dielectric capacitance C and G, C computing module of capacitance compensation coefficient G, It is connected to above-mentioned waveshape detector and the multiplier of G, C computing module, is connected to subtracting of above-mentioned multiplier and Leakage Current module Musical instruments used in a Buddhist or Taoist mass.

The monitoring method of a kind of on-line monitoring device of metallic oxide arrester the most according to claim 1, its feature exists In, comprise the steps:

(1) the initial voltage u and initial leakage current i of metal oxide arrester spark gap are obtained_x；

(2) initial voltage signal is carried out fft analysis, obtain fundamental voltage amplitude u₁, 3 subharmonic voltage amplitudes u₃And frequency w；

(3) by initial voltage and Leakage Current by zero-crossing detector, finding initial voltage is leakage current i corresponding to zero moment_x (t₀)；

(4) by step 2, fundamental voltage amplitude u obtained by 3₁, 3 subharmonic voltage amplitudes u₃, frequency w, leakage current i_x(t₀) band Enter formula (1) and obtain brilliant dielectric capacitance C,

$c=\frac{i_x\left(t_0\right)}{{\mathrm{wu}}_1+3{\mathrm{wu}}_3}---\left(1\right)$

(5) by step 2, fundamental voltage amplitude u obtained by 4₁, 3 subharmonic voltage amplitudes u₃, frequency w, brilliant dielectric capacitance C bring into Formula (2) obtains capacitance compensation coefficient G,

$G=\frac{{\mathrm{wcu}}_1^2+3{\mathrm{wcu}}_3^2}{u_1^2+u_3^2}---\left(2\right)$

(6) by initial voltage signal by phase shifter phase shift counterclockwise 90 °, the voltage u after phase shift is obtained by waveforms detection_sf；

(7) by step 5, capacitance compensation coefficient G, voltage u obtained by 6_sfIt is multiplied by multiplier；

(8) by the leakage current i acquired in step 1_xAnd the result obtained by step 7 subtracted each other by subtractor, obtain resistive electricity Flow component i_R；

(9) by the resistive current component i obtained by step 8_RIt is uploaded to main control chip, transfers data to show by main control chip Show module and GPRS module；

(10) data obtained by step 9 are sent to PC by GPRS module.