CN202854247U - Gapless metal oxide surge lightning arrester no residual voltage monitoring device - Google Patents

Abstract

The utility model relates to the field of lightning arrester online monitoring technology, and particularly relates to a gapless metal oxide surge lightning arrester no residual voltage monitoring device. The online monitoring of the running state of a lightning arrester is carried out through a no residual voltage method. The device comprises a shell body and an internal circuit board. The shell body is provided with an outer cover which is provided with a display screen window. An LED display is installed on an end cover and is displayed from the window. The outer cover is also provided with a projection, a cable threading hole and a socket. The internal circuit board comprises a sensor part, a central processor MCU, a clock circuit, a memory circuit, a signal measuring and converting circuit, a protection circuit and a communication circuit. The device can monitor parameters of full current, resistive current, action times and the like of the lightning arrester in an online way and is provided with functions of local display, remote communication, data storage and the like. The device is suitable for the online monitoring of lightning arresters in different voltage levels, can completely replace a traditional full current meter and an action counter, and has a broad application prospect.

Description

Gapless metal-oxide lighting arrester is without the residual voltage monitoring device

Technical field

The utility model relates to lightning arrester on-line monitoring technique field, relates in particular to a kind of gapless metal-oxide lighting arrester without the residual voltage monitoring device.By the method without residual voltage the lightning arrester running status to be carried out on-line monitoring.

Background technology

Along with the progress of electronic technology with to going deep into that MOA studies, some on-line monitoring instruments have been engendered.These instruments are easy to carry, use simply, need not have a power failure and remove MOA, adopt the mode of manual inspection, directly measure the performance parameters such as leakage current, voltage of MOA, greatly improved work efficiency, avoided the inconvenience of off-line monitoring.But the operating condition of MOA is very complicated, and the impact of Coupling Between Phases electric capacity and system voltage harmonic wave is interweaved and is in the same place.Adopt above-mentioned these on-line monitoring instruments MOA to be monitored also to exist accuracy of detection low, the shortcoming such as real-time is inadequate.Nowadays resistor disc is all installed in the lightning arrester on-Line Monitor Device inside of rig-site utilization, so just so that device leaves residual voltage when being subject to being struck by lightning, and such device can only be measured the total current peak value, can't measure the current in resistance property value, has lacked an important criterion of lightning arrester state.Traditional lightning arrester monitoring device does not have telecommunications functions yet, does not meet the basic demand of current intelligent substation.

The utility model content

The utility model provides a kind of gapless metal-oxide lighting arrester without the residual voltage monitoring device for above-mentioned problems of the prior art.Purpose is in order to realize the on-line monitoring of each electric pressure lightning arrester, can to substitute traditional total current table and operation counter fully, significantly improving work efficiency.

The technical scheme that its technical matters that solves the utility model adopts is:

Gapless metal-oxide lighting arrester is without the residual voltage monitoring device, and comprise shell body and internal circuit board: housing is provided with enclosing cover, and enclosing cover has display screen windows, and light-emitting diode display is installed on the end cap and shows from window; Cover outward and also be provided with projection, cable through wires hole and socket;

Internal circuit board comprises: Sensor section, central processor MCU, clock circuit, memory circuit, signal measurement and translation circuit, holding circuit and telecommunication circuit;

Wherein mutual inductor is connected in the housing, and the mutual inductor extension line links to each other with the circuit board connection terminal; The direct entering signal of circuit board leads leakage current of an arrester is measured and translation circuit, enters central processor MCU after through the signal conversion; Clock circuit is connected with central processor MCU; Memory circuit also is connected with central processor MCU; Central processor MCU sends the data directly to holding circuit and telecommunication circuit, and the RS485 level transmissions by standard is to far-end.

Described display screen windows is sealed by the engineering transparent plastic.

Described projection is the ear shape, is provided with two.

Described enclosing cover material is cast aluminium.

Described socket is provided with two, is five core metal aviation sockets, and wherein the 3rd core is communication interface, and the second core is power interface; The plug portion of socket welds five core shielded cables.

Described mutual inductor adopts little electric current punching mutual inductor.

Described central processor MCU adopts C8051 series high-performance single-chip microcomputer, has 12 AD and SPI, UART interface.

The function that the utility model possesses is: can on-line monitoring lightning arrester total current, the parameter such as current in resistance property, action frequency, and have the functions such as local demonstration, telecommunication, data storage.Device is applicable to the on-line monitoring of each electric pressure lightning arrester, can substitute traditional total current table and operation counter fully.Device also has telecommunications functions, adopts the MODBUS-RTU agreement, standard RS485 communication interface, but messaging parameter flexible configuration, and convenient and comprehensive state monitoring means (main IED) communicates.The Monitoring Data such as total current, current in resistance property and action frequency with timestamp can be in the device storage inside more than 1 year.When the device lightning arrester current value of monitoring surpasses user's setting value, with output alarm signal, in time find the aging or problem of making moist of lightning arrester, prevent the generation of fault.

The utlity model has following advantage and beneficial effect:

Monitoring device adopts the sampling of punching mutual inductor, measure precisely, can residual pressure drop during by thunder-strike current, and be sent to processor after sampled signal nursed one's health, extract first-harmonic and third harmonic through the DFT algorithm, thereby draw more accurate total current and current in resistance property value, the operations staff can check the running status of lightning arrester easily.Can on-line monitoring lightning arrester total current, the parameter such as current in resistance property, action frequency, and have the functions such as local demonstration, telecommunication, data storage.Be applicable to the on-line monitoring of each electric pressure lightning arrester, can substitute traditional total current table and operation counter fully, it has a extensive future.The effect that reaches: 1. accelerate speed and precision that the MOA operating mode is judged; 2. realize telemonitoring and failure prediction; 3. reduce the monitoring expense.The MOA remote online monitoring has than large economy benefit and social effect.

Description of drawings

Fig. 1 is structured flowchart of the present utility model;

Fig. 2 is external structure synoptic diagram of the present utility model;

Fig. 3 is inner structure synoptic diagram of the present utility model.

Among the figure: display screen windows 1, mutual inductor 2, socket 3; projection 4, enclosing cover 5, central processor MCU 6; memory circuit 7, Flash storer 8, signal measurement and translation circuit 9, amplifying circuit 10, reference source circuit 11; negative voltage circuit 12, holding circuit 13, electric capacity 14; holding circuit and telecommunication circuit 15; voltage transient killer tube 16, clock circuit 17, comparer 18.

Embodiment

Below in conjunction with specific embodiment of the utility model and accompanying drawing, the utility model is described in detail.

The utility model be a kind of gapless metal-oxide lighting arrester without the residual voltage monitoring device, hardware components mainly comprises:

Shell body and internal circuit board: housing is provided with enclosing cover 5, and enclosing cover 5 has display screen windows 1, and the LED display is installed on the end cap and shows from window; Also be provided with projection 4, cable through wires hole and socket 3 on the enclosing cover 5; Internal circuit board comprises: Sensor section, central processor MCU 6, holding circuit and telecommunication circuit 15, memory circuit 7, signal measurement and translation circuit 9, electric capacity 14.Wherein mutual inductor 2 is connected in the housing, and mutual inductor 2 extension lines link to each other with the circuit board connection terminal; The direct entering signal of circuit board leads leakage current of an arrester is measured and translation circuit 9, enters central processor MCU 6 after through the signal conversion; Clock circuit 17 is connected with central processor MCU 6; Memory circuit 7 also is connected with central processor MCU 6, is convenient to storaging current and time data.Central processor MCU 6 sends the data directly to holding circuit and telecommunication circuit 15, and the RS485 level transmissions by standard is to far-end.

Enclosing cover 5 materials of monitoring device described in the utility model are cast aluminium, have display screen windows 1 on the end cap, and window is sealed by the engineering transparent plastic.Light-emitting diode display with wide temperature function is installed on the end cap and shows from window.There are two ear shape projections 4 at cast aluminium box back, is used for shell is fixed to lightning arrester base.The shell box portion has the cable through wires hole, and the arrester ground line accesses the earth after passing box body.Two core metal aviation sockets 3 are installed in the housing below, and wherein the 3rd core is communication interface, and the second core is power interface.Plug portion can weld shielded cable.

Internal circuit: sensor adopts little electric current punching mutual inductor 2, adopts resin that mutual inductor is poured onto box body inside, and the mutual inductor extension line is to circuit board connection terminal place.Central processor MCU 6 adopts C8051 series high-performance single-chip microcomputer, has 12 AD and SPI, UART interface.Base when clock chip DS1302 17 adopts the 32.768Hz crystal oscillator to provide high-precision.Memory circuit 7 adopts Flash storer 8 and EEPROM storage chip, respectively can storage of measurement data 16M byte and pointer data 256 bytes.Signal measurement and translation circuit 9, signal enters into signal measurement and translation circuit 9 by mutual inductor 2, and conversion is modulated into and can for the signal of single-chip microcomputer collection, processes through software algorithm through signal.Holding circuit 13 adds voltage transient at the input port of signal and suppresses circuit and be unlikely to impaired under the thunder and lightning occasion with protection and translation circuit.The alternative condition of voltage transient killer tube (TVS) will satisfy: the maximal value that dc breakdown voltage can bear greater than sample circuit:

The maximum impact electric current can bear and flow through the maximum lightning current of lightning arrester.Telecommunication circuit, telecommunication circuit adopts the RS485 circuit, and the differential level transmission mode makes communication distance farther, and anti-interference is stronger, and communication protocol adopts the MODBUS-RTU agreement, and verification can make communications more reliable to data through CRC16.Counting circuit adopts trigger to trigger the singlechip interruption port, thereby carries out tally function.

Principle of work: gapless metal-oxide lighting arrester adopts two CT sample rate current signals and lightning strike signals without the residual voltage monitoring device, gather out leakage current of an arrester by a precision transformer, through signal measurement and translation circuit 9, enter central processor MCU 6, central processor MCU 6 inner AD can arrange startup according to the user, after starting acquisition, processor reads the data of 256 sampled points of a cycle, and through the discrete Fourier algorithm, extract first-harmonic and third harmonic, calculate total current value and the current in resistance property value of current time, and store in the FLASH chip 8, be 1 year storage time, and the user also can transfer the historical data of storer.Tally function is to adopt high-frequency mutual inductor; when lightning arrester lightning strikes or line over-voltage occur when; the electric current that flows out lightning arrester increases suddenly; high-frequency mutual inductor can extract thunderbolt or overvoltage signal, and through overcommutation, 16 protections of TVS voltage transient killer tube; at last to electric capacity 14 chargings; voltage is increased to trigger comparator 18 behind the reference voltage, and comparer 18 output high level enter processor and interrupt, and record this time thunderbolt or overvoltage signal.This device makes timestamp on each current data and the thunderbolt data band by clock chip DS1302 17, is convenient to data query and fault diagnosis.

The utility model is by precision current transformer current signal to be measured, process signal condition and translation circuit convert the voltage signal of processor tolerance interval to, in processor, utilize fast fourier algorithm to calculate, draw lightning arrester total current and current in resistance property.The tally function of device is to adopt the high-frequency mutual inductor sampling, and trigger comparator under the heavy current impact keeps and record.The collection of two kinds of signals all is to adopt the punching mutual inductor, is therefore installing inside without residual voltage, and the fine traditional monitoring device that solved is after lightning arrester is struck by lightning, and device retains the residual voltage height, thereby affects the service life of arrester problem.Device of the present utility model also adopts the discrete Fourier algorithm, well extracts total current and the current in resistance property of lightning arrester, and measuring accuracy is improved.

Gapless metal-oxide lighting arrester without residual voltage monitoring measuring method is: the leakage current of device is through the straight-through current transformer of gapless metal-oxide lighting arrester without the residual voltage monitoring device, current signal enters current-to-voltage converting circuit, current transformation is become voltage signal, be transformed into MCU acceptable voltage magnitude through behind the voltage signal conditioning circuit, entering at last MCU calculates, after through the DFT discrete Fourier transform (DFT), the current signal that gathers decomposites the first-harmonic value of total current and current in resistance property, show data with polling mode and exist in the FLASH storer at display screen, the pointer of storage data leaves among the E2PROM, can be repeatedly erasable; When the host computer request sent data, MCU received order by data communication system, and sends corresponding return data by the UART serial ports.It is described that current transformation is become voltage signal is to adopt high-frequency mutual inductor to respond to the appearance of large electric current, when large electric current being arranged by behind the high-frequency mutual inductor, electric current in the certain amplitude of mutual inductor secondary side output, through forming pulse signal behind the comparator circuit and directly triggering the MCU interrupt function, this moment, MCU record lightning current or superpotential occured once, and the time that Real Time Clock System records is deposited in the FLASH storer together.

One, computing formula:

The ultimate principle of harmonic analysis method is as follows:

Any period function f (t) is as long as satisfy the Di Liheli condition, be that given periodic function is in limited interval, only have limited jump and limited maximum value and minimal value, and the periodic function that runs in the electrotechnics all satisfies this condition usually.Then f (t) all can be decomposed into the Fourier series that is comprised of DC component and each harmonic:

$f\left(t\right)=a_0+(a_1\cos \mathrm{\&omega;t}+b_1\sin \mathrm{\&omega;t})+(a_2\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="120918145204.png"\; state="\{\{state\}\}">cos</figure-callout>}2\mathrm{\&omega;t}+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="120918145204.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\sin 2\mathrm{\&omega;t})+...$

$=a_0+\underset{k=1}{\overset{l}{\mathrm{\&Sigma;}}}(a_k\cos \mathrm{k\&omega;t}+b_k\sin \mathrm{k\&omega;t})---\left(1\right)$

For design factor a _k, b _k, the following formula both sides respectively be multiply by cosk ω t and are got definite integral:

${\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)={\&Integral;}_0^{2\mathrm{\&pi;}}{a}_0\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)+{\&Integral;}_0^2{a}_1\cos \mathrm{\&omega;}t\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)+{\&Integral;}_0^{2\mathrm{\&pi;}}{a}_2\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="120918145204.png"\; state="\{\{state\}\}">cos</figure-callout>}2\mathrm{\&omega;}t\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)+...$

$+{\&Integral;}_0^{2\mathrm{\&pi;}}{b}_1\sin \mathrm{\&omega;}t\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)+{\&Integral;}_0^{2\mathrm{\&pi;}}{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="120918145204.png"\; state="\{\{state\}\}">b</figure-callout>}}_2\sin 2\mathrm{\&omega;}t\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)+...$

According to orthogonality of trigonometric function matter, m, n is arbitrary integer, and m ≠ n, then following definite integral is set up:

${\&Integral;}_0^{2\mathrm{\&pi;}}\sin \mathrm{mxdx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}\cos \mathrm{mxdx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}{\left(\sin \mathrm{mx}\right)}^2\mathrm{dx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}{\left(\cos \mathrm{mx}\right)}^2\mathrm{dx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}\sin \mathrm{mx}\cos \mathrm{nxdx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}\cos \mathrm{mx}\cos \mathrm{nxdx}=0$

${\&Integral;}_0^{2\mathrm{\&pi;}}\sin \mathrm{mx}\sin \mathrm{nxdx}=0$

Then

${\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)=a_k\mathrm{\&pi;}$

So

$a_k=\frac{1}{\mathrm{\&pi;}}{\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\cos \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)$

In like manner, go to multiply by the both sides of (1) formula with sink ω t, and get definite integral,

$b_k=\frac{1}{\mathrm{\&pi;}}{\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\sin \mathrm{k\&omega;td}\left(\mathrm{\&omega;t}\right)$

Consider first-harmonic, its coefficient is

$a_1=\frac{1}{\mathrm{\&pi;}}{\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\cos \mathrm{\&omega;td}\left(\mathrm{\&omega;t}\right)=\frac{2}{T}{\&Integral;}_0^{T}f\left(t\right)\cos \mathrm{\&omega;tdt}$

$b_1=\frac{1}{\mathrm{\&pi;}}{\&Integral;}_0^{2\mathrm{\&pi;}}f\left(t\right)\sin \mathrm{\&omega;td}\left(\mathrm{\&omega;t}\right)=\frac{2}{T}{\&Integral;}_0^{T}f\left(t\right)\sin \mathrm{\&omega;tdt}$

Above fundametal compoment in (1) formula be

A ₁＝a ₁cosωt+b ₁sinωt

Following formula is done some conversion, order

A＝(a ₁+b ₁) ^1/2

A is arranged again ₁=A ₁Sin φ ₁, b ₁=A _1mCos φ ₁, tan φ ₁=a ₁/ b ₁

Then have

A ₁＝A _1msinφ ₁cosωt+A _1mcosφ ₁sinωt

Use trigonometric function and with long-pending relation, can draw A ₁=A _1mSin (ω t+ φ ₁).

A _1mAnd φ ₁Can be by a ₁, b ₁Try to achieve, and a ₁, b ₁Then can try to achieve by numerical integration.By above calculating, can try to achieve amplitude and the phase angle of first-harmonic.Represent respectively corresponding time-domain function with B, A, then the coefficient a of fundamental signal ₁, b ₁For

$a_1=A_{1m}\cos {\mathrm{\&phi;}}_A=\frac{2}{T}{\&Integral;}_0^{T}A\sin \mathrm{\&omega;tdt}$

$b_1=A_{1m}\sin {\mathrm{\&phi;}}_A=\frac{2}{T}A\cos \mathrm{\&omega;tdt}$

In the formula, A _1mThe fundamental voltage amplitude of signal A, φ _AIt is its phase place.Can draw:

${\mathrm{\&phi;}}_A=\arctan \frac{b_1}{a_1}$

$A_{1m}=\sqrt{{a_1}^2+{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="120918145204.png"\; state="\{\{state\}\}">b</figure-callout>}}_2}^2}$

In like manner, for the k rd harmonic signal, its coefficient is:

$a_k=A_k\cos {\mathrm{\&phi;}}_k=\frac{2}{T}{\&Integral;}_0^{T}X\left(t\right)\sin \mathrm{\&omega;tdt}$

$b_k=A_k\sin {\mathrm{\&phi;}}_k=\frac{2}{T}{\&Integral;}_0^{T}X\left(t\right)\cos \mathrm{\&omega;tdt}$

And for in-site measurement, the data that obtain all are situations about dispersing, corresponding coefficient a _k, b _kFor

$a_k=\frac{2}{N}\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(n\right)\sin \left(\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}\right)$

$b_k=\frac{2}{N}\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left(n\right)\cos \left(\frac{2\mathrm{\&pi;}}{N}\mathrm{kn}\right)$

${\mathrm{\&phi;}}_k=\arctan \frac{b_k}{a_k}$

$X_k=\sqrt{{a_{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="120918145204.png"\; state="\{\{state\}\}">k</figure-callout>}}}^2+{{\mathrm{<figure-callout\; id="2"\; label="b\; k"\; filenames="120918145204.png"\; state="\{\{state\}\}">b</figure-callout>}}_k}^2}$

Following formula becomes the computing formula of this mensuration.

Practical application:

The utility model device has successfully applied to south, Changchun 500kV intelligent substation, and carries out site test with Portable arrester testing current instrument and compare, and wherein two groups of lightning arrester data as shown in Table 1 and Table 2.

First group of lightning arrester data of table 1

Second group of lightning arrester data of table 2

Claims (7)

1. gapless metal-oxide lighting arrester comprises shell body and internal circuit board: it is characterized in that without the residual voltage monitoring device:

Housing is provided with enclosing cover (5), and enclosing cover (5) has display screen windows (1), and light-emitting diode display is installed on the end cap and shows from window; Also be provided with projection (4), cable through wires hole and socket (3) on the enclosing cover (5);

Internal circuit board comprises: Sensor section, central processor MCU (6), clock circuit (17), memory circuit (7), signal measurement and translation circuit (9), holding circuit and telecommunication circuit (15);

Wherein mutual inductor (2) is connected in the housing, and mutual inductor (2) extension line links to each other with the circuit board connection terminal; The direct entering signal of circuit board leads leakage current of an arrester is measured and translation circuit (9), enters central processor MCU (6) after through the signal conversion; Clock circuit (17) is connected with central processor MCU (6); Memory circuit (7) also is connected with central processor MCU (6); Central processor MCU (6) sends the data directly to holding circuit and telecommunication circuit (15), and the RS485 level transmissions by standard is to far-end.

2. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described display screen windows (1) is sealed by the engineering transparent plastic.

3. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described projection (4) is the ear shape, is provided with two.

4. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described enclosing cover (5) material is cast aluminium.

5. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described socket (3) is provided with two, is five core metal aviation sockets, and wherein the 3rd core is communication interface, and the second core is power interface; The plug portion of socket (3) welds five core shielded cables.

6. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described mutual inductor (2) adopts little electric current punching mutual inductor.

7. gapless metal-oxide lighting arrester according to claim 1 is characterized in that without the residual voltage monitoring device: described central processor MCU (6) adopts C8051 series high-performance single-chip microcomputer, has 12 AD and SPI, UART interface.

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