CN207007711U

CN207007711U - A kind of TDLAS detects SF6The device of humidity in electrical equipment

Info

Publication number: CN207007711U
Application number: CN201720679744.XU
Authority: CN
Inventors: 张英
Original assignee: Electric Power Research Institute of Guizhou Power Grid Co Ltd
Current assignee: Electric Power Research Institute of Guizhou Power Grid Co Ltd
Priority date: 2017-06-13
Filing date: 2017-06-13
Publication date: 2018-02-13
Anticipated expiration: 2027-06-13

Abstract

The utility model discloses the device that a kind of TDLAS detects humidity in SF6 electrical equipments, the wavelength modulation that a high frequency sinusoidal signal realizes laser is also superimposed while low frequency triangular wave is superimposed in laser drive current, infrared beam is after gas absorbs, electric signal is converted optical signals to by photodetector, subsequently into lock-in amplifier, frequency-doubled signal demodulation through sinusoidal signal first obtains the harmonic signal related to tested gas concentration, again by detecting the size of harmonic signal, so as to obtain the concentration of tested gas, with overcome the deficiencies in the prior art.

Description

A kind of TDLAS detects SF6The device of humidity in electrical equipment

Technical field

It the utility model is related to a kind of TDLAS detections SF₆The device of humidity, belongs to SF in electrical equipment₆Electrical equipment scene Detection technique field.

Background technology

SF₆Moisture is mainly derived from SF in electrical equipment₆New gas or SF₆Itself contains moisture, SF6 equipment in regeneration gas Assembling maintenance overhaul and fill among tonifying Qi process mixed moisture, assembling and maintenance overhaul high-voltage electrical equipment when Wait, moisture of the air included in may be brought into the inside of equipment.Adsorbent among insulating materials and equipment Itself contain water, the moisture divided in air via SF₆Electrical equipment weak seal link and penetrate into inside of equipment etc., SF₆When gas water content is higher, will easily it occur in the phenomenon of insulating materials surface sweating, this can cause equipment exhausted Edge declines, and the accidents such as flashover breakdown can occur serious when.And moisture is too high can cause a series of chain reactions, add Fast device interior corrosion.Detect SF₆The moisture of electrical equipment is very necessary, in ieee standard, national standard, power industry It is required to make Humidity detection in standard and company standard, and defines standard value, it is seen that its necessity.

Existing detection method is mainly SF₆Moisture monitoring in electrical equipment is mainly comprising dew point method, capacitance-resistance method, electrolysis Method and gravimetric method.Dew point method (Cold Mirrors method) is the condensation and humidity for measuring gas contained humidity, and power industry is current at present Measure the main stream approach of humidity.There is also certain weak point for dew point method.If such as have in sulfur hexafluoride gas on a small quantity to steam Hydro carbons or arc cracked product existing for vapour form, these materials before moisture condensation will condensation, so as to influence measurement knot Fruit.In addition, environment temperature is too high or the too low result that can all influence condensation, even condensation is unable to when serious.Capacitance-resistance method is also mesh The main stream approach of preceding measurement humidity.It is disadvantageous in that irreversible decay, and error can be with usage time and number increasingly Greatly, and exist by live electromagnetic interference problem.Electrolysis is not used substantially now, and this is due to measurement system before in-site measurement System is in itself and moist, often there is background values, makes measurement result not accurate enough.Weight rule is referee method, but is only suitable for Laboratory, it is impossible to be used in Site Detection SF₆Humidity in electrical equipment.

Utility model content

The purpose of this utility model is to provide a kind of TDLAS detections SF₆The device of humidity in electrical equipment, driven in laser The wavelength modulation that a high frequency sinusoidal signal realizes laser, infrared light are also superimposed while low frequency triangular wave is superimposed on streaming current Beam converts optical signals to electric signal after gas absorbs, by photodetector, subsequently into lock-in amplifier, through sinusoidal signal Frequency-doubled signal demodulation first obtain the harmonic signal related to tested gas concentration, then by detecting the size of harmonic signal, from And the concentration of tested gas is obtained, with overcome the deficiencies in the prior art.

To achieve the above object, the technical solution adopted in the utility model is that a kind of TDLAS detects SF₆It is wet in electrical equipment The device of degree, including TDLAS controllers, power module, Laser emission end, light path system and receiving terminal, described power supply Module output end is connected with TDLAS controller power source interface inputs；TDLAS controllers respectively with Laser emission end and receiving terminal Connection；Light path system is between Laser emission end and receiving terminal.

Described TDLAS controllers include OEM modules, temperature control modules and expansion module.

Described Laser emission end includes laser and base.

Described light path system is the how anti-chamber absorption cell of long light path or open light path lens.

Described receiving terminal includes photodiode, amplifying circuit, bias circuit and filter circuit, and optical signal first passes through Photodiode detection is converted to faint electric signal, then connects amplifying circuit and electric signal is put by amplifying circuit Greatly, finally circuit is filtered to it after filtering.Wherein bias circuit improves the reaction sensitivity of photodiode.

Collimation unit is provided between described Laser emission end and light path system, collimation unit is lens or optical fiber Collimater.

Condenser lens is provided between described light path system and receiving terminal.

Described Laser emission end, light path system, receiving terminal, collimation unit and condenser lens is on the same line.

Described optical fiber collimator is butterfly.

It is compared with the prior art, the utility model has following technique effect：

, can moisture in detection device at the scene under any temperature first, do not limited by environment temperature

Second, not disturbed by other gas components, SF is accurately detected₆Humidity (moisture) in electrical equipment.

Third, high sensitivity, and not by live electromagnetic interference, and irreversible decay is not present in optical means detection, detects Long lifespan, the Humidity Detection suitable for on-site electrical equipment.

In summary, tunable laser method detection SF₆Moisture completely can be with overcome the deficiencies in the prior art, advantage in gas Substantially.

Brief description of the drawings

Fig. 1 is schematic diagram of device of the present utility model；

Fig. 2 is TDLAS detection principle diagram；

Fig. 3 is H₂O FTIR line charts；

Label symbol explanation in accompanying drawing：

1st, TDLAS controllers；2nd, power module；3rd, Laser emission end；4th, light path system；5th, receiving terminal, 6, collimation Unit, 7, condenser lens.

Embodiment

The utility model is described in further detail below in conjunction with the accompanying drawings.

As Figure 1-3, a kind of TDLAS detections SF of the present utility model₆The device of humidity in electrical equipment, including TDLAS controllers 1, power module 2, Laser emission end 3, light path system 4, receiving terminal 5, collimation unit 6, condenser lens 7, The output end of power module 2 is connected with the power interface input of TDLAS controllers 1；TDLAS controllers 1 respectively with Laser emission end 3 Connected with receiving terminal 5；Light path system 4 is between Laser emission end 3 and receiving terminal 5；Light path system (4) and receiving terminal (5) condenser lens (7) is provided between；Laser emission end (3), light path system (4), receiving terminal (5), collimation unit (6) With condenser lens (7) on the same line；Optical fiber collimator is butterfly.

TDLAS is Tunable Diode Laser Absorption Spectroscopy abbreviation, and translator of Chinese is can Tuning diode laser absorption spectrum.Tunable diode laser absorption spectroscopy (TDLAS) technology is to utilize diode laser Wavelength tuning characteristic, the absorption spectrum in the range of the characteristic absorption spectrum of object gas is obtained, so as to determine object gas Property or quantitative analysis.

Firstly the need of object gas analysis spectral line is determined, so that it is determined that the wavelength of system laser light source.In TDLAS technologies In, gas molecule target absorption choice of spectrum typically follows following several principles：

1. the absorption line of selection must have enough line strengths, to improve detection sensitivity and signal to noise ratio；

2. light, which is modulated, by tunable laser method can avoid other gas componants to selected absorption line Produce interference；

3. ensure the needs for thering is reliable laser diode light source to meet absorption line detection.

The data that spectrum analysis provide according to HITRAN databases.HITRAN databases are real by Cambridge aerodynamic investigation The high accuracy migration molecular database of the annual continuous renewal of room exploitation is tested, it is widely used in Trace gas detection, big Gas pollutant research etc., and to provide various parameters using Lambert-Beer laws, for example, absorption line line by force, position with And some widen coefficient etc..By this spectra database to H₂The analysis of the infrared spectral characteristic of O gases, determines object gas H₂O optimum analysis spectral line is 2460nm, i.e. the 2nd peak in Fig. 3.H₂O absorption lines are as shown in figure 3, be shown as wave number in figure.

OEM modules are Laser emission Control architecture in Fig. 1, control the emitting portion of laser.Other template contrals receive Hold the parts such as amplifying circuit, bias circuit, filter circuit, photoelectric diode.

Generally, due to which molecular structure is different, every kind of gas is only to those energy photon corresponding with its molecular entergy level There is absorption, be spectrally reflected as the characteristic absorption spectrum of every kind of gas.When gas is irradiated by infrared beam, the gas Body will absorb the luminous energy of its corresponding characteristic wavelength of a part, reduce the light intensity of infrared beam, according to Bill's lambert's law, Attenuation degree can by detecting light intensity obtains the concentration information of gas.However, in mid infrared region, gas is to light Absorptance is fainter.Therefore, the key technology that tiny signal is detection is extracted from ambient noise.

Using t unable filter (Tunable Diode Laser Absorption Spectroscopy, TDLAS) improve detection sensitivity.System general principle in laser drive current as shown in Fig. 2 fold Add and the wavelength modulation that a high frequency sinusoidal signal realizes laser is also superimposed while low frequency triangular wave, infrared beam is inhaled through gas After receipts, electric signal is converted optical signals to by photodetector, subsequently into lock-in amplifier, the frequency-doubled signal through sinusoidal signal Demodulation just obtains the harmonic signal related to tested gas concentration.By detecting the size of harmonic signal, realize that tested gas is dense The measurement of degree.

Using infrared tuning semiconductor laser absorption spectrum gas detection method, with reference to highly sensitive wavelength modulation spectrum technology With compact multiple reflections optical absorption pool technology, realize that moisture detects.Fig. 1 show design principle, mainly by optics System, electronics and Data collection and precessing system.Optical system includes being used for H₂The near-infrared dfb semiconductor of O spectral detections LASER Light Source, open compact multiple reflections long light path optical absorption pond and with reference to absorption cell, and optical collimation lenses and Transmission Fibers, electronics include laser temperature and current control circuit, modulation generating circuit, phase-sensitive detection electricity Road, photodetector etc. are formed, and semiconductor laser passes through optical fiber output, and optical absorption is coupled into by incidence window after collimation Pond, light beam are emitted in absorption cell after multiple reflections by being emitted optical window, and outgoing beam is by with reference to quilt after absorption cell Focus on a photodetector photosurface, photosignal send phase sensitive detection circuit to carry out second-harmonic detection.Data acquisition The second harmonic signal absorbed to gas with processing system is carried out after A/D conversions and digital collection through multiple accumulation process, to Real time inversion gas concentration.

It is described above, only specific embodiment of the present utility model, but the scope of protection of the utility model is not limited to In this, any one skilled in the art can readily occur in change in the technical scope that the utility model discloses Or replace, it should all cover within the scope of protection of the utility model, therefore, the scope of protection of the utility model should be with the power The protection domain that profit requires is defined.

Claims

1. a kind of TDLAS detects SF₆The device of humidity in electrical equipment, including TDLAS controllers (1), power module (2), laser Transmitting terminal (3), light path system (4) and receiving terminal (5), it is characterised in that：Described power module (2) output end with TDLAS controllers (1) power interface input connects；TDLAS controllers (1) respectively with Laser emission end (3) and receiving terminal (5) Connection；Light path system (4) is between Laser emission end (3) and receiving terminal (5).

A kind of 2. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described TDLAS controllers (1) include OEM modules, temperature control modules and expansion module.

A kind of 3. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Laser emission end (3) include laser and base.

A kind of 4. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Light path system (4) be the how anti-chamber absorption cell of long light path or open light path lens.

A kind of 5. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Receiving terminal (5) receive optical signal faint electric signal is converted to by photodiode, then by transfer wire connection put Big circuit, amplifying circuit are amplified to electric signal, and amplifying circuit connects filter circuit by transfer wire, after filtering circuit It is filtered, wherein bias circuit is connected by transfer wire with photoelectric diode.

A kind of 6. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Laser emission end (3) and light path system (4) between be provided with collimation unit (6), collimation unit (6) is lens or optical fiber Collimater.

A kind of 7. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Light path system (4) and receiving terminal (5) between be provided with condenser lens (7).

A kind of 8. TDLAS detections SF according to claim 1₆The device of humidity in electrical equipment, it is characterised in that：It is described Laser emission end (3), light path system (4), receiving terminal (5), collimation unit (6) and condenser lens (7) in same straight line On.

A kind of 9. TDLAS detections SF according to claim 6₆The device of humidity in electrical equipment, it is characterised in that：It is described Optical fiber collimator be butterfly.