CN203465384U - GIS partial discharge narrow band electromagnetic wave signal detection system - Google Patents

Abstract

The utility model discloses a GIS partial discharge narrow band electromagnetic wave signal detection system. The system is mainly composed of a narrow band antenna which is placed to be opposite to a pouring hole of a GIS metal ring, a filter, an amplifier and a signal collector. The voltage signal output end of the narrow band antenna is connected with the voltage signal input end of the filter. The voltage signal output end of the filter is connected with the voltage signal input end of the amplifier. The voltage signal output end of the amplifier is connected with the voltage signal input end of the signal collector. The narrow band antenna receives an electromagnetic wave signal radiated from the pouring hole, converts the electromagnetic wave signal into a voltage signal, and transmits the voltage signal to the filter. The voltage signal undergoes filtering of the filter, is transmitted to the amplifier for signal amplification, and finally is sent to the signal collector for recording and analyzing. According to the utility model, in an effective narrow band range, the gain is much higher than the gain of the existing wideband detection device; an interference signal in a wide band range is avoided; the signal to noise ratio is improved; and the requirements of spot detection are fully met.

Description

The arrowband electromagnetic wave signal detection system of GIS shelf depreciation

Technical field

The utility model relates to a kind of arrowband electromagnetic wave signal detection system of GIS apparatus local discharge.

Background technology

Along with the continuous increase of society to electricity needs, power industry is developed rapidly, and at present, the safe operation of large-scale power transmission network has become the significant problem that power industry is paid close attention to.Research shows, gas insulated combined electrical equipment (Gas Insulated Switchgear, hereinafter to be referred as GIS) and potential device inside take insulation fault as many, and the tendency of insulation fault often shows as shelf depreciation, it is generally acknowledged, shelf depreciation in high-tension apparatus has a strong impact on Electric Field Distribution, causes electric field distortion and insulating material corrosion, finally causes insulation breakdown.The broadband electromagnetic wave signal that shelf depreciation in GIS is usually expressed as fast-pulse electric current and excites thus.The frequency range of electromagnetic wave signal can reach several GHz, even higher.By being coupled, this electromagnetic wave signal can detect the partial discharges fault that occurs in GIS device interior.In order to improve signal to noise ratio (S/N ratio), avoid the complicated undesired signals such as the on-the-spot corona existing, the working band of existing detection system mainly in superfrequency (Ultra High Frequency, hereinafter to be referred as UHF) band limits, that is: 0.3～1.5GHz.In recent years, GIS shelf depreciation UHF detection technique has obtained greatly developing and applying in China.Apply this technology and repeatedly found the inner shelf depreciation defect of GIS, avoided the generation of GIS insulation fault, for the safe and reliable operation of assurance electric system has been made significant contribution.

As shown in Figures 1 to 3, for receiving the electromagnetic installation of sensors of UHF in GIS device interior (referring to Fig. 1,2) or being installed on disc insulator 10 outside surfaces (referring to Fig. 3).UHF sensor 1 when GIS equipment 2 inside or disc insulator outside surface, the non-constant width of electromagnetic wave signal frequency that it receives.From signal spectrum, in 300MHz～1.5GHz frequency range, there is energy distribution.Therefore, existing UHF sensor all adopts broadband sensor, such as capacitance type transducers, equiangular spiral antenna, log-periodic antenna, bow-tie type antenna etc.; Existing UHF amplifier and wave filter also all adopt broadband operation pattern.Detection system shown in Fig. 2 comprises coupling mechanism 3, conversion connector 4, UHF sensor 1, cable 6 and oscillograph 7.Detection system shown in Fig. 3 comprises broad-band antenna 8 and UHF detector 9.

In recent years, along with the development of urban planning and construction and the development of backcountry power transmission network, in order to save transformer station's floor area and to reduce operation maintenance, the GIS equipment adopting in newly-built transformer station is more and more.In order to improve Earthing Reliability, to prevent the corrosion of rugged surroundings to insulator, on increasing GIS equipment, adopted the insulator with becket.Becket wraps up whole insulator.For the ease of insulator castable, on becket, there is a plug hole, for pouring into epoxy material.Owing on existing most of GIS equipment, built-in UHF sensor not being installed, and because the stopping of becket, UHF electromagnetic wave can only be through plug hole to external radiation.But, extremely faint to extraradial UHF signal, utilize existing external broad-band antenna and detection system, extremely low because of the sensitivity of detection system, 100pC and above shelf depreciation only can be detected, can not reach the requirement of Site Detection.

Utility model content

The utility model object is to provide a kind of arrowband electromagnetic wave signal detection system that can improve the GIS shelf depreciation of detection sensitivity and signal to noise ratio (S/N ratio), can reach the requirement of On-site Partial Discharge Detection in GIS.

Above-mentioned purpose of the present utility model realizes by the following technical solutions: a kind of arrowband electromagnetic wave signal detection system of GIS shelf depreciation, it is characterized in that: it is mainly by the narrow-band antenna for placing over against the plug hole of the upper becket of GIS, wave filter, amplifier and signal picker form, the voltage signal output end of described narrow-band antenna is connected with the voltage signal input end of wave filter, the voltage signal output end of described wave filter is connected with the voltage signal input end of amplifier, the voltage signal output end of described amplifier is connected with the voltage signal input end of signal picker, described narrow-band antenna is sent to wave filter after receiving the electromagnetic wave signal being given off by plug hole and being translated into voltage signal, after device filtering processing, be resent to amplifier after filtering and carry out signal amplification, be finally sent to signal picker and record and analyze.

The gain of the utility model within the scope of effective arrowband be far away higher than existing wide band detection method, and avoided the undesired signal in broad frequency range, greatly improved signal to noise ratio (S/N ratio).Reached the requirement of Site Detection completely.

The centre frequency of described narrow-band antenna is the cutoff frequency f of the main mould of electromagnetic wave that gives off of the plug hole of becket on GIS equipment _c, the bandwidth of operation of narrow-band antenna is 50～150MHZ, the gain of narrow-band antenna improves greatly than broad-band antenna, and antijamming capability is strong.The passband of described wave filter is f _c-50MHZ～f _c+ 50MHZ, has further improved signal to noise ratio (S/N ratio), and the minimum value of the analog bandwidth of described signal picker is at most f _c-50MHZ.

The work bandwidth of amplifier described in the utility model is f _c-50MHZ～f _c+ 50MHZ, has improved detection sensitivity greatly.

Plug hole described in the utility model is rectangular opening, cutoff frequency f _ccomputing formula be:

$f_c=\frac{c}{2a\sqrt{{\mathrm{\μ}}_r{\mathrm{\ϵ}}_r}}---\left(1\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum; A is the length of plug hole, and what b was plug hole is wide, ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

Plug hole described in the utility model is circular hole, cutoff frequency f _ccomputing formula be:

$f_c=\frac{u_{11}^{\&prime;}\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HDA00003749958500011.png,HDA00003749958500012.png"\; state="\{\{state\}\}">c</figure-callout>}}{2\mathrm{\&pi;r}\sqrt{{\mathrm{\&mu;}}_r{\mathrm{\&epsiv;}}_r}}---\left(2\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum; u ₁₁' be constant; R is the radius of plug hole; ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

Compared with prior art, the utlity model has following significant effect:

The gain of the utility model within the scope of effective arrowband is far away higher than existing wide band detection method, highly sensitive, and has avoided the undesired signal in broad frequency range, has greatly improved signal to noise ratio (S/N ratio).Reached the requirement of Site Detection completely.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.

Fig. 1 is existing for receiving the schematic diagram of the electromagnetic installation of sensors of UHF in GIS equipment;

Fig. 2 is the detection system of the built-in UHF sensor that the comprises Fig. 1 structural representation when measuring;

Fig. 3 is existing for receiving the electromagnetic installation of sensors of UHF in the schematic diagram of disc insulator outside surface;

Fig. 4 is the principle schematic that the utility model embodiment 1 calculates rectangle plug hole cutoff frequency;

Fig. 5 is the principle schematic that the utility model embodiment 2 calculates circular plug hole cutoff frequency;

Schematic diagram when Fig. 6 is the measurement of the utility model detection system.

Embodiment

Embodiment 1

A kind of arrowband electromagnetic wave signal coupling process of measuring GIS shelf depreciation of the utility model, comprises the following steps:

(1) calculate the cutoff frequency f of the main mould of electromagnetic wave that the plug hole by becket 18 on GIS equipment gives off _c; In the present embodiment, GIS equipment is the 252kVGIS of certain manufacturer production.Plug hole 15 on this GIS insulator 19 is approximately rectangle, and referring to Fig. 4, according to Electromagnetic theory, the main mould in rectangular waveguide inside is TE ₁₀ripple, the computing formula of its cutoff frequency is:

$f_c=\frac{c}{2a\sqrt{{\mathrm{\&mu;}}_r{\mathrm{\&epsiv;}}_r}}---\left(1\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum, that is: 3 * 10 ⁸m/s; A is the length of plug hole, and what b was plug hole is wide, ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

Rectangular waveguide cross section is rectangle, and its size (long * wide) is: 0.045m * 0.020m.The relative permeability μ of its inner mould material _rbe 1, relative dielectric constant ε _rbe 3.8.Make a=0.045m, b=0.020m; C=3 * 10 ⁸m/s, μ _r=1, ε _r=3.8.According to formula (1), calculate cutoff frequency, obtain: f _c=1.71GHz.

The measurement bandwidth of determining detection system is 1.66～1.76GHz.

(2) with cutoff frequency f _cas the centre frequency of detection system, detection system is mainly communicated to connect and forms successively by narrow-band antenna 11, wave filter 12, amplifier 13 and signal picker 14, and the centre frequency of narrow-band antenna 11 is cutoff frequency f _c=1.71GHz, generally, more than 1.5GHz, the bandwidth of operation of narrow-band antenna is 100MHZ, and this narrow-band antenna has stronger directivity and gain, and the gain of narrow-band antenna improves greatly than broad-band antenna, and antijamming capability is strong.The passband of wave filter is 1.66～1.76GHz, and at cutoff frequency place, gain is-3dB, and stop band gain is-20dB further to have improved signal to noise ratio (S/N ratio).The work bandwidth of amplifier is 1.66～1.76GHz, in the gain of cutoff frequency place, is 3dB, and passband gain is 20dB, has greatly improved detection sensitivity.

In the present embodiment, signal picker adopts the Wavemaster8620A type oscillograph of U.S. Li Ke company, and its analog bandwidth can reach 0-6GHz.The minimum value that is the analog bandwidth of signal picker is at most f _c-50MHZ.

(3), while measuring, narrow-band antenna 11 is arranged over against plug hole;

(4) narrow-band antenna 11 changes into voltage signal by the electromagnetic wave signal being given off by plug hole and is sent to wave filter 12, this voltage signal carries out filtering by wave filter 12 and amplifies after processing by amplifier 13, by signal picker 14, receiving this voltage signal records and analyzes, test result shows, to the output amplitude of the shelf depreciation of GIS inside 5pC, is 10mV.Therefore, the utility model is used in the shelf depreciation that GIS inside is detected at plug hole place.

The gain of the utility model within the scope of effective arrowband is far away higher than existing wide band detection method, highly sensitive, and has avoided the undesired signal in broad frequency range, has greatly improved signal to noise ratio (S/N ratio).Reached the requirement of Site Detection completely.

As shown in Figure 6, use the detection system 17 of the arrowband electromagnetic wave signal coupling process of above-mentioned measurement GIS shelf depreciation, it is mainly comprised of narrow-band antenna 11, wave filter 12, amplifier 13 and signal picker 14 for placing over against the plug hole of the upper becket of GIS, the voltage signal output end of narrow-band antenna 11 is connected with the voltage signal input end of wave filter 12, the voltage signal output end of wave filter 12 is connected with the voltage signal input end of amplifier 13, and the voltage signal output end of amplifier 13 is connected with the voltage signal input end of signal picker 14; Narrow-band antenna 11 is sent to wave filter 12 after receiving the electromagnetic wave signal being given off by plug hole and being translated into voltage signal, after device 12 filtering processing, be resent to amplifier 13 after filtering and carry out signal amplification, be finally sent to signal picker 14 and record and analyze.

Wherein, the centre frequency of narrow-band antenna is the cutoff frequency f of the main mould of electromagnetic wave that gives off of the plug hole of becket on GIS equipment _c=1.71GHz, the bandwidth of operation of narrow-band antenna is 100MHZ, the passband of wave filter is f _c-50MHZ～f _c+ 50MHZ, is 1.66～1.76GHz, and at cutoff frequency place, gain is-3dB, and stop band gain is-20dB; The analog bandwidth of signal picker is 0-6GHz, and the work bandwidth of amplifier is f _c-50MHZ～f _c+ 50MHZ, is 1.66～1.76GHz, in the gain of cutoff frequency place, is 3dB, and passband gain is 20dB.

Embodiment 2

The difference of the present embodiment and embodiment 1 is: as shown in Figure 5, plug hole 16 is circular hole, and circular waveguide cross section is circular, and according to Electromagnetic theory, the main mould in circular waveguide inside is TE ₁₁ripple, cutoff frequency f _ccomputing formula be:

$f_c=\frac{u_{11}^{\&prime;}\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HDA00003749958500011.png,HDA00003749958500012.png"\; state="\{\{state\}\}">c</figure-callout>}}{2\mathrm{\&pi;r}\sqrt{{\mathrm{\&mu;}}_r{\mathrm{\&epsiv;}}_r}}---\left(2\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum; u ₁₁' be constant value 1.841; R is the radius of plug hole; ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

Embodiment of the present utility model is not limited to this; according to foregoing of the present utility model; according to ordinary skill knowledge and the customary means of this area; do not departing under the above-mentioned basic fundamental thought of the utility model prerequisite; the bandwidth of operation of the utility model narrow-band antenna is 50～150MHZ; therefore the utility model can also be made modification, replacement or the change of other various ways, within all dropping on the utility model rights protection scope.

Claims (5)

1. the arrowband electromagnetic wave signal detection system of a GIS shelf depreciation, it is characterized in that: it is mainly comprised of narrow-band antenna, wave filter, amplifier and signal picker for placing over against the plug hole of the upper becket of GIS, the voltage signal output end of described narrow-band antenna is connected with the voltage signal input end of wave filter, the voltage signal output end of described wave filter is connected with the voltage signal input end of amplifier, and the voltage signal output end of described amplifier is connected with the voltage signal input end of signal picker; Described narrow-band antenna is sent to wave filter after receiving the electromagnetic wave signal being given off by plug hole and being translated into voltage signal, after device filtering processing, be resent to amplifier after filtering and carry out signal amplification, be finally sent to signal picker and record and analyze.

2. the arrowband electromagnetic wave signal detection system of GIS shelf depreciation according to claim 1, is characterized in that: the centre frequency of described narrow-band antenna is the cutoff frequency f of the main mould of electromagnetic wave that gives off of the plug hole of becket on GIS equipment _c, the bandwidth of operation of narrow-band antenna is 50～150MHZ, the passband of described wave filter is f _c-50MHZ～f _c+ 50MHZ, the minimum value of the analog bandwidth of described signal picker is at most f _c-50MHZ.

3. the arrowband electromagnetic wave signal detection system of GIS shelf depreciation according to claim 2, is characterized in that: the work bandwidth of described amplifier is f _c-50MHZ～f _c+ 50MHZ.

4. according to the arrowband electromagnetic wave signal detection system of the GIS shelf depreciation described in claim 1～3 any one, it is characterized in that: described plug hole is rectangular opening, cutoff frequency f _ccomputing formula be:

$f_c=\frac{c}{2a\sqrt{{\mathrm{\&mu;}}_r{\mathrm{\&epsiv;}}_r}}---\left(1\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum; A is the length of plug hole, and what b was plug hole is wide, ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

5. according to the arrowband electromagnetic wave signal detection system of the GIS shelf depreciation described in claim 1～3 any one, it is characterized in that: described plug hole is circular hole, cutoff frequency f _ccomputing formula be:

$f_c=\frac{u_{11}^{\&prime;}c}{2\mathrm{\&pi;r}\sqrt{{\mathrm{\&mu;}}_r{\mathrm{\&epsiv;}}_r}}---\left(2\right)$

Wherein, c is electromagnetic wave velocity of wave in a vacuum; u ₁₁' be constant; R is the radius of plug hole; ε _r, μ _rbe respectively relative dielectric constant and the relative permeability of the dielectric material of filling in plug hole.

Images