CN1888924A - Transformer local discharging ultra-wide band sensor array positioning system and method thereof - Google Patents

Abstract

This is a transformer local discharge ultrawide-band sensor array orientation system. Four elements ultrawide-band RF sensor arrays are micro size wide-band antenna and their designed upper limit frequency isn't lower than 6 GHz. The elements aren't in one circumcircle and the space between of element isn't smaller than 80cm. Set each group of sensor array at both side of the transformer iron core. Respectively connect the feeder to the four ultrawide-band amplifiers of 1GHz-6GHz by same length and low wastage high frequency RF cable, and the export ending of amplifier connects to the high-speed collecting figure oscillograph. Test the arriving time difference of the element test single with the others by the sensor array to find the position of the transformer local discharge radiant point. The orientation system and method adopt the existing instrument and achieve the veracious orientation and can be used on line.

Description

Transformer local discharging ultra-wide band sensor array positioning system and method thereof

Technical field

The invention belongs to power transformer online measuring technique field, be meant a kind of transformer local discharging ultra-wide band sensor array positioning system and method thereof especially.Non-plane (or hither plane) the radio frequency sensor array of arranging with circumscribed circle of a kind of employing a plurality of (more than 2 or 2) 4 array elements carries out system and the method thereof that Partial Discharge in Power Transformer detects.

Background technology

Along with development and national economy, more and more higher to the requirement of electric system reliability service, and power transformer is the hinge equipment of electric system, its reliability of operation is directly connected to the safety and stablization of electric system.To the statistical results show of physical fault, insulation fault is the main cause that influences the normal operation of transformer, and shelf depreciation is to cause the major reason of insulation fault.

Current, the state maintenance of development power equipment has become a kind of inexorable trend.Not only there is important booster action shelf depreciation location to the assessment of the extent of injury of shelf depreciation accurately, and can provide the guidance of science for the repair based on condition of component of transformer, so that the maintainer carries out maintenance of equipment with a definite target in view, help fixing a breakdown rapidly and improving the maintenance level, also structural design, the raising manufacturing technology level of improving transformer had directive significance simultaneously.

The partial discharge of transformer location technology has been studied more than 20 year at home and abroad, and at present, the method for existing shelf depreciation location mainly contains two kinds of ultrasonic locating method, electrical Location methods.But up to now these classic methods all can't realize accurately, localization of fault reliably.

Method for ultrasonic locating is to begin development the eighties, is tending towards ripe a kind of partial discharge positioning method the nineties, and present this method has obtained using more widely.But the practice of rig-site utilization shows that this method position success rate is very low, and locating effect is very poor.The main cause of its location failure has following 3 points: at first, especially tank envelope is very serious to the decay of ultrasonic signal for various acoustic mediums in the transformer, and the sensitivity of ultrasonic sensor is lower, cause ultrasonic method to be difficult to detection signal effectively thus, cause can't locate or locate inaccurate.Secondly, the electromagnetic interference (EMI) of site environment is strong, and the ultrasonic sensor poor anti jamming capability of using at present causes to be difficult to effective using ultrasound method and accurately to locate.At last, transformer device structure complexity, the equivalent velocity of sound of ultrasonic signal in different medium are difficult to determine that accurately location algorithm is perfect not to the utmost in addition, cause the location inaccurate.

Be called the electrical Location method according to partial discharge pulse along the method that the Transformer Winding propagation law carries out analyzing and positioning.Different with localization by ultrasonic, the position that electric method is determined is the electric position that takes place of shelf depreciation but not geometric position.Although more to the Transformer Winding The Characteristic Study, and multiple electrical Location method has correspondingly appearred, up to the present, seldom adopt electric method in the reality.Its main cause is: at first, the on-the-spot behaviour of electric method institute is complicated, so the scope of application is subjected to bigger restriction; The second, big to the accurate modeling difficulty of Transformer Winding, work is loaded down with trivial details, versatility is poor; The 3rd, because transformer winding structure complexity and shelf depreciation happening part is different, the pulse regularity that propagates into winding overhang is not strong, and its accurate positioning is not high.And because the influence of on-the-spot strong electromagnetic interference (EMI), pulse current method is difficult to online effectively application.

To have highly sensitive a, antijamming capability strong and be suitable for the advantage of online detection in view of the UHF method, and people begin to explore by UHF and detect the location of carrying out Partial Discharge in Power Transformer at present.Someone's the shortest optical path principle of giving chapter and verse is carried out the idea of Partial Discharge in Power Transformer location at present, but research also finds because local discharge signal intensity is limited, and large scale entity metal assemblies such as iron core are very strong to the decay that the UHF signal causes, the latency measurement that causes thus is inaccurate, the latency measurement error in addition up to the number nanoseconds more than, this requires for the partial discharge of transformer orientation problem, and the fault for centimetre magnitude positions in several meters spatial dimension, consider that electromagnetic wave is with near light velocity propagation, the positioning error that causes thus is (even can reach several meters) greatly, therefore is difficult to directly carry out according to the shortest optical path principle the accurate location of partial discharge of transformer.

Summary of the invention

The purpose of this utility model is to avoid above-mentioned weak point of the prior art and a kind of transformer local discharging ultra-wide band sensor array positioning system and method thereof is provided.The present invention has developed non-plane (or hither plane) the radio frequency sensor array of arranging with circumscribed circle of a kind of employing a plurality of (more than 2 or 2) 4 array elements and has carried out system and the method thereof that Partial Discharge in Power Transformer detects.

Purpose of the present invention can reach by following measure:

A kind of transformer local discharging ultra-wide band sensor array positioning system, its positioning system is constructed as follows:

High speed acquisition digital oscilloscope by 4 array element ultra-wide band radio-frequency sensor arraies, isometric low-loss radio frequency feed line, 1GHz-6GHz ultra broadband amplifier, 6GHz analog bandwidth is formed;

4 array element ultra-wide band radio-frequency sensor arraies, the array element of its sensor array is the miniature broadband antenna, its design upper limiting frequency be not less than 6GHz, each array element of the arrangement requirement of sensor array not on same circumscribed circle, floor plan, array element distance is not less than 80cm;

Near the transformer oil tank wall low place or in the magnetic shielding district both sides unshakable in one's determination one group of sensor array at least respectively is installed, each sensor is drawn with isometric low-loss radio frequency feed line, with isometric low-loss high-frequency radio-frequency cable feeder line is received respectively on the ultra broadband amplifier of 4 road 1GHz-6GHz drawing the feeder line structure place, adopted isometric low-loss high-frequency radio-frequency cable that amplifier output is connected on the high speed acquisition digital oscilloscope equally.

A kind of transformer local discharging ultra-wide band sensor array localization method:

(1) analog bandwidth high speed acquisition digital oscilloscope is set to triggering mode, adopts the follow-up relatively concussion wave-shape amplitude of Mintrop wave peak-to-peak amplitude higher, and pulse width do not have the direct wave that becomes big, adopts the sensor array of this side to detect;

(2) selected a certain road array element detection signal is as the reference benchmark, and it is poor with respect to the time of arrival of this array element detection signal to measure other each array elements, and known velocity of wave c and each sensor coordinates are obtained the position of partial discharge of transformer radiation source.

The present invention has following advantage compared to existing technology:

This transformer local discharging ultra-wide band sensor array positioning system and method thereof adopt existing typing instrument and equipment, can directly buy on market, can be not impaired by side transformer, and accurate positioning is reliable.

But this transformer local discharging ultra-wide band sensor array positioning system and method on-line measurement thereof, method is simple, overlaps simple.

Description of drawings

Fig. 1. four array element ultra-wide band radio-frequency sensor arraies, its four array element are that rhombus is arranged, wherein acute angle is 30～60 ° in the rhombus, and array element distance L is more than the 80cm.

Fig. 2. the both sides unshakable in one's determination sensor installation array synoptic diagram of transformer, its S ₁, S ₂, S ₃, S ₄Be the iron core one side senser array of transformer, and S ₂' ... opposite side sensor array unshakable in one's determination for transformer.

Fig. 3 mistiming is read synoptic diagram, its [τ ₁₂, τ ₁₃, τ ₁₄]=[1.543,0.877 ,-0.179], unit: ns.

Embodiment

The present invention proposes a kind of transformer local discharging ultra-wide band sensor array positioning system and method thereof, non-plane (or hither plane) the radio frequency sensor array of arranging with circumscribed circle of a kind of employing a plurality of (more than 2 or 2) 4 array elements carries out system and the method thereof that Partial Discharge in Power Transformer detects, and can effectively improve measuring accuracy.

Transformer local discharging ultra-wide band sensor array positioning system is made up of the high speed acquisition digital oscilloscope of 4 array element ultra-wide band radio-frequency sensor arraies, isometric low-loss radio frequency feed line, 1GHz-6GHz ultra broadband amplifier, 6GHz analog bandwidth, and its each unit is installed, connects as follows:

1, the installation of sensor array

Shown in accompanying drawing 1. 4 array element ultra-wide band radio-frequency sensor arraies, wherein the array element of sensor array is the miniature broadband antenna, and its design upper limiting frequency is not less than 6GHz.Each array element of the arrangement requirement of sensor array is not on same circumscribed circle, floor plan or almost plane are arranged, array element distance is not less than 80cm, satisfy the rhombus of this requirement and arrange that (the rhombus acute angle is between 30 °-60 °) are preferable, other satisfy array element not the layout on same circumscribed circle also can.

In the transformer production stage not oil-filled before, near can be the transformer oil tank wall low place or near sensor installation array magnetic shielding; Another mode is exactly during transformer returns factory's overhaul, after transformer oil bleeds off, and near low place the transformer oil tank wall or near sensor installation array magnetic shielding.Must guarantee at least respectively to install one group of sensor array in both sides unshakable in one's determination.Isometric sensor feeder line is drawn by transformer valve, manhole, hand hole or special perforate position by special hermetically-sealed construction.

Shown in the both sides unshakable in one's determination sensor installation array synoptic diagram of accompanying drawing 2 transformers, isometric low-loss radio frequency feed line is drawn by specialized structure from transformer valve, manhole or hand hole position, also can go between by the mode of transformer production producer perforate in advance on tank wall, the lead division bit architecture carries out excellent sealing, and a sensor array at least respectively is installed in the transformer core both sides.

2, connect detection system

In transformer operation or pressurization experimentation, transformer is inner to be existed discharge and needs further to determine spark location when carrying out follow-up diagnosis or maintenance when detecting, and with isometric low-loss high-frequency radio-frequency cable feeder line is received respectively on the ultra broadband amplifier of 4 road 1GHz-6GHz drawing the feeder line structure place.The isometric low-loss high-frequency radio-frequency cable of same employing is connected to amplifier output on the high speed acquisition digital oscilloscope.

3, test data sheet signal

Read shown in the synoptic diagram as 3 mistimings of accompanying drawing, draw signal and amplify the back is connected directly to the 6GHz analog bandwidth by the high-frequency radio frequency concentric cable high-speed figure collection oscillograph through the amplifier of four road 1GGHz-6GHz bandwidth.Position detecting system is set to triggering mode, according to the speed of the Mintrop wave peak of gathering discharge waveform, can distinguish discharge signal and whether stop still along direct path arrival sensor through iron core with respect to size, distortion situation and the rising edge of follow-up concussion wave-shape amplitude.Concrete grammar is if the follow-up relatively concussion wave-shape amplitude of Mintrop wave peak-to-peak amplitude is lower, and obviously pulse width becomes big, and then discharge signal is for sensor received after iron core stops and diffraction takes place; Otherwise be direct wave.According to the position of discharge source with respect to iron core, i.e. discharge occurs in which side unshakable in one's determination, detects with regard to the sensor array that adopts this side.According to the size of detection signal-to-noise ratio, decision record discharge waveform size.If disturb greatlyyer, then write down a large amount of discharge waveform samples, to eliminate random disturbance and ambient noise signal, improve the noise that detects, and the discharge signal reference position is highlighted;

Selected a certain road array element detection signal is as the reference benchmark, measure other each array elements with respect to the time of arrival of this array element detection signal poor-be signal time delay, as input parameter, carry out the search location of discharge source with detection signal time delay information by mistiming algorithm (also claiming the hyperboloid algorithm).

Under the situation of selected frequency band of the present invention and sensor mounting means, the radiofrequency signal that shelf depreciation produces can effectively penetrate horizontal, vertical oil duct of Transformer Winding and propagate in the mode of nearly straight line, and this conclusion is confirmed by a large amount of emulation and test.This fact has greatly been simplified the location algorithm development difficulty, has reduced the mistiming location algorithm and has implemented difficulty.Therefore, can be based on signal rectilinear propagation modelling mistiming algorithm.

4, specific algorithm is as follows the mistiming:

Measure the relative time delay between good each sensor array element, and it can be located the coordinate position of shelf depreciation point as parameter substitution location algorithm.

For example 3 mistimings of accompanying drawing read the actual measurement time delay that provides in the synoptic diagram and are [τ 12, and τ 13, and τ 14]=[1.543,0.877 ,-0.179], unit: ns.Utilize delay inequality can determine discharge radiation source, (x, y is z) to sensor S to establish discharge radiation source P ₁(x ₁, y ₁, z ₁) travel-time t ₁, then the P point is to S ₁Apart from r ₁Satisfy

$r_1=\sqrt{{(x-x_1)}^2+{(y-y_1)}^2+{(z-z_1)}^2}=c\·t_1---\left(1\right)$

In the formula, c is electromagnetic velocity of wave.

If signal arrives sensor S _i(x _i, y _i, z _i) and reference sensor S ₁Relative time error be τ _1i=t _i-t ₁, i=2,3,4, then satisfy relation of plane down between the coordinate of radiation source P and each sensor

$\left\{\begin{array}{c}{r}_1=\sqrt{{(x-x_1)}^2+{(y-y_1)}^2+{(z-z_1)}^2}=c\&CenterDot;t_1\\ {\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="A20061010366500102.png,A20061010366500103.png"\; state="\{\{state\}\}">r</figure-callout>}}_2=\sqrt{{(x-x_2)}^2+{(y-y_2)}^2+{(z-z_2)}^2}=c\&CenterDot;(t_1+{\mathrm{\&tau;}}_{12})\\ r_3=\sqrt{{(x-x_3)}^2+{(y-y_3)}^2+{(z-z_3)}^2}=c\&CenterDot;(t_1+{\mathrm{\&tau;}}_{13})\\ r_4=\sqrt{{(x-x_4)}^2+{(y-y_4)}^2+{(z-z_4)}^2}=c(t_1+{\mathrm{\&tau;}}_{14})\end{array}\right.---\left(2\right)$

Measure each sensor with respect to sensor S ₁Relative time error τ _1i, known velocity of wave c and each sensor coordinates then can be obtained the position of radiation source by formula (2).From geometric meaning, what formula (2) was represented is the hyperboloid equation, so the mistiming location algorithm is also referred to as the hyperboloid algorithm.A P three bi-curved intersection points are in fact put in office.

This transformer local discharging ultra-wide band sensor array positioning system and method thereof adopt existing typing instrument and equipment, and accurate positioning is reliable, but on-line measurement, and method is simple.

Claims (2)

1, a kind of transformer local discharging ultra-wide band sensor array positioning system is characterized in that: its positioning system is constructed as follows:

High speed acquisition digital oscilloscope by 4 array element ultra-wide band radio-frequency sensor arraies, isometric low-loss radio frequency feed line, 1GHz-6GHz ultra broadband amplifier, 6GHz analog bandwidth is formed;

4 array element ultra-wide band radio-frequency sensor arraies, the array element of its sensor array is the miniature broadband antenna, its design upper limiting frequency be not less than 6GHz, each array element of the arrangement requirement of sensor array not on same circumscribed circle, floor plan, array element distance is not less than 80cm;

Near the transformer oil tank wall low place or in the magnetic shielding district both sides unshakable in one's determination one group of sensor array at least respectively is installed, each sensor is drawn with isometric low-loss radio frequency feed line, with isometric low-loss high-frequency radio-frequency cable feeder line is received respectively on the ultra broadband amplifier of 4 road 1GHz-6GHz drawing the feeder line structure place, adopted isometric low-loss high-frequency radio-frequency cable that amplifier output is connected on the high speed acquisition digital oscilloscope equally.

2, a kind of transformer local discharging ultra-wide band sensor array localization method is characterized in that:

(1) analog bandwidth high speed acquisition digital oscilloscope is set to triggering mode, adopts the follow-up relatively concussion wave-shape amplitude of Mintrop wave peak-to-peak amplitude higher, and pulse width do not have the direct wave that becomes big, adopts the sensor array of this side to detect;

(2) selected a certain road array element detection signal is as the reference benchmark, and it is poor with respect to the time of arrival of this array element detection signal to measure other each array elements, and known velocity of wave c and each sensor coordinates are obtained the position of partial discharge of transformer radiation source.

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