CN1851489A - Variable frequency high-voltage motor insulated local discharge measuring method and its special measuring instrument - Google Patents
Variable frequency high-voltage motor insulated local discharge measuring method and its special measuring instrument Download PDFInfo
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- CN1851489A CN1851489A CN 200610020866 CN200610020866A CN1851489A CN 1851489 A CN1851489 A CN 1851489A CN 200610020866 CN200610020866 CN 200610020866 CN 200610020866 A CN200610020866 A CN 200610020866A CN 1851489 A CN1851489 A CN 1851489A
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Abstract
The present invention features adopting 100--200 MHz high frequency current high frequency current transducer sensing frequency conversion motor insulative partial discharge signal, and transmitting it into broadband filter amplifier to proceed filtering amplification process, and through data processing device processing to obtain test result. Said method can effectively proceed partial discharge detection to frequency conversion motor insulation system under frequency conversion high voltage condition, thereby realizing evaluate to motor state of insulation.
Description
Affiliated field
The present invention relates to a kind of method of testing and tester thereof of local discharge of electrical equipment, relate in particular to a kind of method of testing and tester thereof that is used for the electrical machine insulation shelf depreciation under the frequency conversion condition of high voltage.
Background technology
The frequency control kinematic train has unrivaled superiority in Electrified Transmission, have been widely used in fields such as communications and transportation, the energy, machineries.But, seriously restricted applying of this technology because variable-frequency control technique causes electrical machine insulation system premature failure easily.In the inversion output loop of frequency conversion speed-adjusting system, output current signal is the pulse waveform that is subjected to the modulation of pulse width modulator (PWM) carrier signal, this modulation waveform is because be subjected to the high-speed transitions of frequency control switch to produce steep voltage wave, and steep voltage wave produces bigger reflected voltage ripple again by long cable.Because the wave impedance of variable-frequency motor significantly greater than the wave impedance of cable, causes variable-frequency motor can be subjected to the pulse front edge voltage of about twice input voltage amplitude, is in operation and will causes the variable-frequency motor coil covering that serious shelf depreciation takes place.The frequency of frequency conversion system is much larger than common power frequency in addition, for GTO type high power contravariant element, the carrier frequency of its PWM is 500Hz-2kHz, and the high carrier frequency of the PWM of IGBT type high power contravariant element can reach 40kHz, this makes the partial discharge phenomenon of electrical machine insulation layer significantly strengthen, shelf depreciation has been quickened the aging even accumulation puncture of electricity of turn-to-turn insulation, directly influences the steady operation of frequency control kinematic train.Therefore, shelf depreciation is the one of the main reasons that electrical machine insulation wears out, lost efficacy under the effect of PWM frequency conversion voltage.Need monitor variable frequency high-voltage motor insulated partial discharge phenomenon, collect the information of fault discharge, for research platform is set up in the state of insulation assessment of motor under the frequency conversion condition of high voltage, for the reliability service of guaranteeing the frequency control kinematic train provides technical foundation.
Under the effect of frequency conversion high pressure, what electrical machine insulation bore is that pulsewidth is the square-wave pulse of the steep rising edge of 20ns-5 μ s, and its amplitude reaches thousands of volts and even higher.The equivalent upper limiting frequency of square-wave pulse rise time correspondence and the equivalent upper limiting frequency of local discharge signal differ about 2 orders of magnitude, but amplitude differs 106 grades, be that the variable-frequency power sources frequency band is 100kHz～50MHz, voltage is generally the kV level, and the local discharge signal frequency band range upper limit can reach 500MHz, and amplitude mostly is the mV level.It is very difficult to extract faint discharge signal in the very big zone of this electric pressure span, requires sensor to have wide working band.Existing method of testing and tester thereof are mainly drafted according to IEC60270 and GB7354-87 standard, are only applicable to power frequency (50/60Hz) or DC condition.
Existing Partial discharge detector has RLC to detect impedance type and Rogovski coil type.Wherein:
RLC detects impedance type and comes down to a kind of Hi-pass filter, when it is used for detecting discharge signal under the frequency conversion condition of high voltage, because its transitional zone is too wide, doubly to power pulse signal attenuation 10-100, still than the high 2-3 of a discharge signal order of magnitude, so Chang Buneng detects discharge signal effectively; And RLC impedance detection type sensor and tested circuit have direct electrical connection, in a single day sample takes place under the effect of frequency conversion high pressure puncture, and easily sensor and follow-on test circuit are produced harm; Simultaneously, under continuous high frequency pulse power supply, the influence of circuit stray capacitance and stray inductance is bigger, can make the structural parameters that detect impedance change, and parameters such as measurement frequency band are drifted about influence test effect.
The Rogovski coil type mostly is winding around on air core and the current sensor that constitutes, comes the induction discharge signal by the electric current mutual inductance.Core material mostly is MnZn, and magnetic core generally is only applicable to the following low frequency of 1MHz like this, and high frequency performance is relatively poor; Traditional coil-winding mode makes induced signal be subject to the influence of stray capacitance and the influence of external interference signals.
The frequency band range of the current sensor of Gou Chenging mostly is from tens kHz to hundreds of kHz like this, can't intactly tell local discharge signal and power pulse signal under the frequency conversion condition of high voltage; And because passband is low excessively, the energy of local discharge signal is all seriously flooded by the power pulse signal, can not obtain required discharge signal well.In a word, existing under the effect of frequency conversion high pressure the detection method of the local discharge signal of electrical machine insulation and tester thereof still belong to blank at home and abroad.
Summary of the invention
Purpose of the present invention just provides a kind of electrical machine insulation local discharge measuring method that is used under the frequency conversion condition of high voltage.Can solve effectively under the frequency conversion condition of high voltage variable-frequency motor insulation system is carried out Partial Discharge Detection, thereby realization is to the assessment of electrical machine insulation state.
The present invention solves its technical matters, the technical scheme that is adopted is: a kind of variable frequency high-voltage motor insulated local discharge measuring method, it is characterized in that: adopt the High Frequency Current Sensor of 100MHz-200MHz to induce the local discharge signal that variable-frequency motor insulate, send into the broadband filter amplifier and carry out filter amplifying processing, and draw test result by the data processing equipment processing.
Compared with prior art, the invention has the beneficial effects as follows: adopt the 100MHz-200MHz High Frequency Current Sensor to obtain discharge signal, both can avoid the main energy of power supply signal, can effectively be coupled to local discharge signal again by the mutual inductance mode; And by the broadband filter amplifier discharge signal is extracted accurately and efficiently, analysis draws test result based on data processing equipment.
Another object of the present invention provides a kind of dedicated tester of realizing above-mentioned method of testing, and the working band of this tester is wide, highly sensitive, signal to noise ratio (S/N ratio) is high, good reliability.
The present invention realizes the dedicated tester of above-mentioned method of testing, and it consists of: frequency band be the inductive frequency conversion electrical machine insulation local discharge signal of 100MHz-200MHz High Frequency Current Sensor, the signal that induces is carried out the broadband filter amplifier of filter amplifying processing and the filtering amplifying signal is carried out the data processing equipment that statistical study is handled; High Frequency Current Sensor, broadband filter amplifier and data processing equipment are linked to each other successively by the high frequency coaxial shielded cable.
Adopt this dedicated tester can realize above-mentioned method of testing of the present invention easily.Evidence, this dedicated tester working band is wide, the response sensitivity height, and good high frequency characteristics and dynamic perfromance are arranged.Measurement sensitivity can reach 1 skin coulomb, frequency response range: 100MHz～200MHz under-3dB, the rise time of step response is 20ns, has the better linearity degree.
During experiment test, tested variable frequency high-voltage motor insulated line is passed the inner chamber of shielding cavity of the central column of High Frequency Current Sensor, the simulation of variable-frequency pulse generator produces power pulse voltage and puts on this sample, regulating impulse voltage, rising along with pulse voltage, shelf depreciation occurs and amplitude increases, and the increased frequency of discharge.Sense the discharge signal that produces in the sample on the inductive coil of High Frequency Current Sensor, and obtain electrical signal of reaction, the time rate of change of electric current in this electrical signal of reaction and the sample (being time differential) is proportional, this signal is by behind the integrating resistor integration, and the signal of output is the voltage signal that is directly proportional with shelf depreciation electric current in the tested sample.After the broadband filter filtering of level is amplified later, can detect the shelf depreciation in the tested sample.For the high-voltage signal of the kilovolt level in the flat-top zone of power pulse voltage, with respect to discharge signal, its over time rate be zero, therefore on current sensor, can not produce induced voltage, promptly power pulse voltage can not exert an influence in the discharge test instrument.This experiment test can produce the variable-frequency pulse environment of various simulations as required, sets up research platform for the state of insulation assessment of motor under the frequency conversion condition of high voltage, provides technical foundation for the reliability service of guaranteeing the frequency control kinematic train easily.
The present invention is except can carrying out above-mentioned simulated experiment test, and also the insulator pin of the variable-frequency high-voltage motor that the scene can be used directly places the inner chamber of shielding cavity of the central column of High Frequency Current Sensor to carry out on-the-spot test.
Consisting of of above-mentioned High Frequency Current Sensor: inductive coil earlier on circular magnetic core around, and then behind a circle, draw along walking in the opposite direction with coil along the outer peripheral edges of annulus magnetic core; Between two exits and connect integrating resistor; High Frequency Current Sensor is wrapped in the shielding cavity of central column, has the slit that is parallel to the annulated column center line on the internal chamber wall of this shielding cavity.
As perpendicular to the disturbing magnetic field of annular direction the time, the some overhangs that are surrounded on magnetic core will produce induced potential, thereby influence the precision of High Frequency Current Sensor, produce test error.In the High Frequency Current Sensor of the present invention, inductive coil earlier on circular magnetic core around, and then behind a circle, draw along walking in the opposite direction with coil along the outer peripheral edges of annulus magnetic core.The induced potential that this outer peripheral edges coil is produced is opposite with the end turn induced potential direction of wounded core, can offset effectively perpendicular to the influence to High Frequency Current Sensor of the disturbing magnetic field of annular direction, has improved signal to noise ratio (S/N ratio) of the present invention.
High Frequency Current Sensor is wrapped in the shielding cavity of central column, has the slit that is parallel to the annulated column center line on the internal chamber wall of this shielding cavity.Shielding cavity can shield the interference that reduces external magnetic field effectively, reduces the adverse effect to High Frequency Current Sensor; Simultaneously have the slit at inner chamber, again can the actual induction discharge signal.
Around 30 circles-40 circle, circular magnetic core is a nickel zinc magnetic core to above-mentioned inductive coil on the ring of circular magnetic core, and the impedance of integrating resistor and high frequency coaxial shielded cable is 50 Ω.The high frequency characteristics of nickel zinc magnetic core is good, can guarantee the high frequency performance of sensor; The impedance of integrating resistor and high frequency coaxial shielded cable is 50 Ω, can avoid detected local discharge signal to reflect in transmission course backward like this, causes decay.
Above-mentioned broadband filter amplifier is made of quadravalence Butterworth low-pass filter and the series connection of quadravalence Butterworth Hi-pass filter, and low-pass filtering resistance in the low-pass filter and the high-pass filtering resistance in the Hi-pass filter are adjustable resistance; Be close on the shell of broadband filter amplifier and be enclosed with the double-level-metal gauze screen, shell and gauze screen common ground.
The adjustable filter amplifier of the frequency band of Gou Chenging can be regulated bandwidth between 100MHz-200MHz like this, at different frequency conversion systems, the corresponding bandwidth of regulating, realization is for the discharge frequency band external signal decay 80dB of specific frequency conversion system, promptly decay 10000 times, also be about to the power supply high-frequency pulse signal that sensors coupled comes and decay to below the 10mV.The discharge signal of wider bandwidth can intactly detect under the specific operation of assurance particular system.This filter amplifier is placed the double-level-metal gauze screen, prevent on-the-spot 1kHz-300MHz Electromagnetic Interference effectively.And High Frequency Current Sensor and filter amplifier shield respectively, have reduced influencing each other between the two.
The invention will be further described below in conjunction with the drawings and specific embodiments.
Description of drawings
Fig. 1 is the structural representation of the embodiment of the invention.
Fig. 2 is broadband filter amplifier circuit theory diagrams in the embodiment of the invention.
Embodiment
Embodiment
Fig. 1,2 illustrates, a kind of embodiment of the present invention is: a kind of variable frequency high-voltage motor insulated local discharge measuring method is: the local discharge signal that adopts the High Frequency Current Sensor 1 inductive frequency conversion electrical machine insulation of 100MHz-200MHz, send into broadband filter amplifier 2 and carry out filter amplifying processing, and obtain test result by data processing equipment 3 processing.
A kind of dedicated tester that is used to realize above-mentioned method of testing, it consists of: frequency band be 100MHz-200MHz the inductive frequency conversion electrical machine insulation local discharge signal High Frequency Current Sensor 1, the signal that induces is carried out the broadband filter amplifier 2 of filter amplifying processing and the filtering amplifying signal is carried out the data processing equipment 3 that statistical study is handled; High Frequency Current Sensor 1, broadband filter amplifier 2 and data processing equipment 3 are linked to each other successively by high frequency coaxial shielded cable 4.
Consisting of of High Frequency Current Sensor 1: inductive coil 15 earlier on circular magnetic core 14 around, and then behind a circle, draw again along walking in the opposite direction with coil along the outer peripheral edges of annulus magnetic core; Between two exits and connect integrating resistor 13; High Frequency Current Sensor 1 is wrapped in the shielding cavity of central column, has the slit that is parallel to the annulated column center line on the internal chamber wall of this shielding cavity.Inductive coil 15 on circular magnetic core 14 around the number of turn be 35 circles, circular magnetic core 14 is a nickel zinc magnetic core, integrating resistor 13 is 50 Ω with the impedance of high frequency coaxial shielded cable 4.
Broadband filter amplifier 2 is made of quadravalence Butterworth low-pass filter 21 and 22 series connection of quadravalence Butterworth Hi-pass filter, and high-pass filtering resistance R 3, R4 in the low-pass filtering resistance R 1 in the low-pass filter 21, R2 and the Hi-pass filter 22 are adjustable resistance; Be close on the shell of broadband filter amplifier 2 and be enclosed with the double-level-metal gauze screen, this gauze screen and shell common ground.
High Frequency Current Sensor 1 circular magnetic core 14 internal diameter sizes are 45mm; Inductive coil 15 adopts the enameled wire coiling, and the shielding cavity material is a copper, and outside dimension is 90mm, and endoporus is of a size of 18mm, and the shielding cavity upper and lower part is fastenedly connected with screw; One deck of the shell double layer screen net of broadband filter amplifier 2 is made of copper, another layer is fabricated from iron.
Data processing equipment 3 of the present invention can adopt existing computer data processing system to carry out analyzing and processing to gathering the data of coming.
Claims (5)
1, a kind of variable frequency high-voltage motor insulated local discharge measuring method, it is characterized in that: the local discharge signal that adopts High Frequency Current Sensor (1) the inductive frequency conversion electrical machine insulation of 100MHz-200MHz, send into broadband filter amplifier (2) and carry out filter amplifying processing, and obtain test result by data processing equipment (3) processing.
2, a kind of dedicated tester that is used to realize the described method of testing of claim 1, it consists of: frequency band be the inductive frequency conversion electrical machine insulation local discharge signal of 100MHz-200MHz High Frequency Current Sensor (1), the signal that induces is carried out the broadband filter amplifier (2) of filter amplifying processing and the filtering amplifying signal is carried out the data processing equipment (3) that statistical study is handled; High Frequency Current Sensor (1), broadband filter amplifier (2) and data processing equipment (3) are linked to each other successively by high frequency coaxial shielded cable (4).
3, dedicated tester according to claim 2, it is characterized in that: the consisting of of described High Frequency Current Sensor (1): inductive coil (15) earlier circular magnetic core (14) go up around, and then behind a circle (15A), draw along walking in the opposite direction with coil along the outer peripheral edges of annulus magnetic core; Between two exits and connect integrating resistor (13); High Frequency Current Sensor (1) is wrapped in the shielding cavity of central column, has the slit that is parallel to the annulated column center line on the internal chamber wall of this shielding cavity.
4, dedicated tester according to claim 3, it is characterized in that: described inductive coil (15) circular magnetic core (14) go up around the number of turn be 30 circles-40 circles, circular magnetic core (14) is a nickel zinc magnetic core, and integrating resistor (13) is 50 Ω with the impedance of high frequency coaxial shielded cable (4).
5, dedicated tester according to claim 2, it is characterized in that: described broadband filter amplifier (2) constitutes the low-pass filtering resistance (R in the low-pass filter (21) by quadravalence Butterworth low-pass filter (21) and quadravalence Butterworth Hi-pass filter (22) series connection
1, R
2) and Hi-pass filter (22) in high-pass filtering resistance (R
3, R
4) be adjustable resistance; Be close on the shell of broadband filter amplifier (2) and be enclosed with the double-level-metal gauze screen, this gauze screen and shell common ground.
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| CN 200610020866 CN1851489A (en) | 2006-05-22 | 2006-05-22 | Variable frequency high-voltage motor insulated local discharge measuring method and its special measuring instrument |
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| CN101900779A (en) * | 2010-07-28 | 2010-12-01 | 西南交通大学 | Method for measuring lightning shielding failure trip-out rate of high-voltage power transmission line by combining topography |
| CN102135594A (en) * | 2011-01-30 | 2011-07-27 | 太原理工大学 | Insulation state monitoring device of high voltage motor for main fan used for mine |
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| CN103744006A (en) * | 2014-01-07 | 2014-04-23 | 海南金海浆纸业有限公司 | Localization diagnosis method for partial discharge generated by looseness in high-voltage electrical equipment |
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| CN102156236A (en) * | 2010-02-11 | 2011-08-17 | 致茂电子(苏州)有限公司 | Master/slave detection device and high-temperature upflow transformer of sensing module thereof |
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| CN101900779B (en) * | 2010-07-28 | 2012-10-17 | 西南交通大学 | Method for measuring lightning shielding failure trip-out rate of high-voltage power transmission line by combining topography |
| CN102135594A (en) * | 2011-01-30 | 2011-07-27 | 太原理工大学 | Insulation state monitoring device of high voltage motor for main fan used for mine |
| CN102135594B (en) * | 2011-01-30 | 2016-01-20 | 太原理工大学 | Insulation state monitoring device of high voltage motor for main fan used for mine |
| CN103308827A (en) * | 2013-05-22 | 2013-09-18 | 东莞市高能电气股份有限公司 | Voltage aging test method and device for composite insulator |
| CN103308827B (en) * | 2013-05-22 | 2016-08-24 | 长园高能电气股份有限公司 | Composite insulator voltage aging test method and assay device |
| CN103744006A (en) * | 2014-01-07 | 2014-04-23 | 海南金海浆纸业有限公司 | Localization diagnosis method for partial discharge generated by looseness in high-voltage electrical equipment |
| CN103744006B (en) * | 2014-01-07 | 2016-03-23 | 海南金海浆纸业有限公司 | High voltage electric equipment inside loosens the shelf depreciation positioning diagnosticing method produced |
| CN104777386A (en) * | 2015-04-22 | 2015-07-15 | 西南石油大学 | Failure analyzing and detecting system for cable accessories |
| CN106154200A (en) * | 2016-06-15 | 2016-11-23 | 贵州电网有限责任公司六盘水供电局 | Portable GIS local discharge high frequency sensors test device and method of testing |
| CN106154200B (en) * | 2016-06-15 | 2023-04-07 | 贵州电网有限责任公司六盘水供电局 | Portable GIS partial discharge high-frequency sensor testing device and testing method |
| CN107167717A (en) * | 2017-07-20 | 2017-09-15 | 云南电网有限责任公司电力科学研究院 | A kind of local discharge signal blocking device |
| CN107167717B (en) * | 2017-07-20 | 2024-02-06 | 云南电网有限责任公司电力科学研究院 | Partial discharge signal blocking device |
| CN109270453A (en) * | 2018-09-15 | 2019-01-25 | 中船重工西安东仪科工集团有限公司 | It is a kind of for testing the device and method of pulse motor load capacity |
| CN109270453B (en) * | 2018-09-15 | 2023-09-01 | 中船重工西安东仪科工集团有限公司 | Device and method for testing load capacity of pulse motor |
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| CN110161395B (en) * | 2019-05-29 | 2021-02-26 | 苏州半唐电子有限公司 | Method and system for monitoring insulation state of inverter driving motor on line |
| CN111239562A (en) * | 2020-02-10 | 2020-06-05 | 桑原电机(大连)有限公司 | High-voltage motor insulation detection method and device |
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