CN104251953A - Diagnosis method and device for loosening faults of on-load tap switch contact of power transformer - Google Patents
Diagnosis method and device for loosening faults of on-load tap switch contact of power transformer Download PDFInfo
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- CN104251953A CN104251953A CN201410461241.6A CN201410461241A CN104251953A CN 104251953 A CN104251953 A CN 104251953A CN 201410461241 A CN201410461241 A CN 201410461241A CN 104251953 A CN104251953 A CN 104251953A
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Abstract
The invention discloses a diagnosis method for loosening faults of an on-load tap switch contact of a power transformer. The diagnosis method comprises the following steps: carrying out real-time monitoring on a switching movement process of a tap switch; taking the back half part of an energy maximum point of a time-domain signal from a monitored signal and avoiding the energy maximum point in the time-domain signal; carrying out time-domain transformation analysis; determining a spectral line with a larger amplitude of a signal time domain in a range of 800-1000Hz through analyzing; comparing, and showing that the tap switch has the loosening faults of the switch contact if the spectral line is remarkably increased when being compared with a normal state of the tap switch. The invention further discloses a diagnosis device for the loosening faults of the on-load tap switch contact of the power transformer. The fault characteristic quantity disclosed by the invention can accurately reflect the loosening faults of the tap switch contact; the characteristics are remarkable and the repeatability is good and universality on the tap switches with the same type is realized. The technical engineer for diagnosing the loosening faults of the on-load tap switch contact is simple to realize and a sensor is convenient to mount. A microcomputer is used for detecting, processing and diagnosing so that the performance is reliable and the diagnosis method and the diagnosis device are convenient to realize.
Description
Technical field
What the present invention relates to is a kind of method and device of power transformer on load tap changer contact slap fault diagnosis, belongs to electrical control engineering field.
Background technology
Maintenance strategy based on on-line monitoring and fault diagnosis technology will become the inexorable trend of future development.ULTC is very important power transmission and transforming equipment in electric system, it can not only steady load center voltage, and be get in touch with electrical network, adjustment load trend, improvement without indispensable visual plants such as the distribution of work, be widely used in electrical network.
Load ratio bridging switch (On-Load TapChanger, OLTC) all installed by 110kV a large amount of at present and above transformer, and its function completes transformer regulating under bringing onto load state.The running status of load ratio bridging switch directly has influence on the height of the operation of power transformer, the adjustment of electric system and the quality of power supply.According to statistics, load ratio bridging switch fault is one of main fault of power transformer, and failure rate is only second to winding failure.And along with the increase of increasing of applying in electrical network of ULTC and the average daily times of pressure regulation of separate unit shunting switch, the fault of load ratio bridging switch has the trend of increase.Carry out the condition monitoring and fault diagnosis of shunting switch, Timeliness coverage shunting switch is abnormal, significant to safe operation of power system, and has a good application prospect.
Contact slap is one of main fault of tapping switch for electric power transformer.The repeated stock of holding capacity in shunting switch handoff procedure, causing contact slap, as diagnosed not in time, contact even can be caused to come off after repeatedly switching.After contact comes off, very large working current has to independently bear (shunting switch double-throw contact often two groups work side by side) by another group contact in handoff procedure.Another group contact heavy overload, heating, as found not in time, can burn tapping switch contact very soon, whole switch and transformer cannot be worked.In addition, after contact slap, switching contact is loose contact in handoff procedure, causes serious electric arc, also easily makes switching contact burn.
Also do not have reliable diagnostic method to the fault of shunting switch at present, the method in research mainly contains based on the method (as three-ratio method) of dissolved gas analysis, based on the supervision and analysis method of vibration, the diagnostic method etc. based on thermonoise.But due under shunting switch normal operating condition, because of deciliter action of contact, also corresponding gas can be produced in oil, therefore, analytical approach based on oil dissolved gas is difficult to realize at present: the diagnosis based on thermonoise propagates into outside transformer owing to sending out after sub-connecting switch of transformer fault thermonoise thermogenetic, shunting switch fault diagnosis is carried out by installing noise transducer detection on transformer case, this is have obvious fault based on shunting switch contact and produced serious heating (gentle heat can not produce obvious thermonoise) on the one hand, thermonoise propagates into transformer outside on the other hand, the energy loss of signal is large, add various interference, (the various noise of transformer running environment is a lot of engineering to be difficult to realization, particularly electromagnetic noise, ground unrest is very large, much larger than causing the overheated energy passing to signal outside oil tank of transformer because of contact slap fault): owing to causing the factor of vibration a lot of in shunting switch handoff procedure, vibration during the gunlock action of particularly shunting switch is very large, difficulty is brought to vibration analysis, therefore the key based on the shunting switch fault diagnosis of vibration is the characteristic signal finding energy faults in monitored signal, in addition, after monitoring method and monitoring signal analysis method also affect shunting switch thus the accuracy of diagnosis is fallen.
Summary of the invention
What the present invention proposed is method and the device of power transformer on load tap changer contact slap fault diagnosis, its object is intended to the problems referred to above for existing in OLTC fault diagnosis, according to OLTC operation characteristic, and in conjunction with its normal vibration characteristics different with during fault, the characteristic signal that can reflect tapping switch contact looseness fault has been found through theoretical analysis and experiment, namely after tapping switch contact looseness fault, its vibration signal, through suitably process, will produce the spectral line that an obvious amplitude is larger within the scope of 800 ~ 1000Hz in frequency-region signal.Take monitoring and signal analysis method, whether contain this feature according in measured signal, whether diagnosis shunting switch exists contact slap fault, realizes the monitoring and diagnosis of tapping switch contact looseness fault.
Technical solution of the present invention: the method for power transformer on load tap changer contact slap fault diagnosis, it is characterized in that one, Real-Time Monitoring is carried out to shunting switch switching action process, in the signal of monitoring, get the latter half of the main energy of time-domain signal, and avoid Energy maximum value point in time-domain signal; Two, time-frequency transformation analysis is carried out; Three, by analysis, determine the spectral line that amplitude within the scope of 800 ~ 1000Hz of signal frequency domain is larger: four, compare, this spectral line comparatively shunting switch normal condition obviously increases, tapping switch contact looseness fault occurs.
The device of power transformer on load tap changer contact slap fault diagnosis, its structure installs vibration transducer on sub-connecting switch of transformer, the output terminal of vibration transducer connects with the input end of signal conditioning circuit, the output terminal of signal conditioning circuit connects with the input end of Acquisition Instrument, the output terminal of Acquisition Instrument connects with the input end of signal processor, and the output terminal of signal processor is connected with display input end.Signal processor and display can have been replaced by a microcomputer (industrial computer).If the voltage signal that sensor is suitable sized by exporting, or Acquisition Instrument is with charge amplifier, then sensor exports the input end directly connecing Acquisition Instrument, can omit special signal conditioning circuit.
Beneficial effect:
1) fault characteristic value found can accurately reflect tapping switch contact looseness fault, and feature is obvious, reproducible, confirms to have good ubiquity to the shunting switch of same type through great many of experiments.
2) the load tap changer contact slap fault diagnosis engineering increased based on spectral line peak value between vibration frequency-region signal 800-1000Hz realizes simple, and sensor is easy for installation.
3) adopt industrial computer to carry out detecting, process and diagnosing, dependable performance, software simulating is convenient, and man-machine interface is friendly, and diagnosis is directly perceived.
Accompanying drawing explanation
Fig. 1 is the structured flowchart of fault diagnosis system; Wherein 1 is sub-connecting switch of transformer, and 2 is sensors, and 3 is signal conditioning circuits, and 4 is Acquisition Instruments, and 5 is signal processors, and 6 is display (with computer generations for signal processor 5 and display 6);
Fig. 2 is the test block diagram of diagnostic system;
Fig. 3 is the frequency domain figure of vibration signal under shunting switch normal condition;
Fig. 4 is the frequency domain figure of vibration signal under tapping switch contact looseness fault state;
Fig. 5 is the vibration signal frequency domain figure under tapping switch contact normal condition;
Fig. 6 is the vibration signal frequency domain figure under tapping switch contact looseness fault state;
Fig. 7 is the vibration signal frequency domain figure under tapping switch contact normal condition;
Fig. 8 is the vibration signal frequency domain figure under shunting switch touches looseness fault state;
Fig. 9 is the vibration signal frequency domain figure under tapping switch contact normal condition;
Figure 10 is the vibration signal frequency domain figure under tapping switch contact looseness fault state.
Embodiment
Contrast accompanying drawing 1, its structure installs vibration transducer 2 on sub-connecting switch of transformer 1, sensor output signal send Acquisition Instrument 4 to gather after signal conditioning circuit 3 is changed, after use Acquisition Instrument 4 collects coherent signal, carry out signal analysis by signal processor 5, the image obtained and diagnostic result are shown on the display 6.Annexation between them: sub-connecting switch of transformer 1 connects with the input end of sensor 2, the output terminal of sensor 2 connects with the input end of signal conditioning circuit 3, the output terminal of signal conditioning circuit (prior art) 3 connects with the input end of Acquisition Instrument 4, the output terminal of Acquisition Instrument 4 connects with the input end of signal processor 5, and the output terminal of signal processor 5 is connected with display 6.If the voltage signal that sensor is suitable sized by exporting, or Acquisition Instrument is with charge amplifier, then sensor exports the input end directly connecing Acquisition Instrument, does not need special signal conditioning circuit.
Described vibration transducer 2 is piezoelectric type acceleration vibration transducer, and model is CA-YD-103.Piezoelectric type acceleration vibration transducer is also known as piezoelectric accelerometer, and it utilizes the piezoelectric effect of some crystalline material to make, and its output electricity is proportional to the vibration acceleration value of testee.
Described Acquisition Instrument model is Gould 77-0801-NET, is a kind of high-accuracy general data collecting instrument, and is furnished with charge amplifier, sample to input signal, and can send computing machine by image data.
Signal processor 5 and display 6 are completed by analysis software by a common computer (microcomputer).
Because Acquisition Instrument has charge amplifier, so, do not need special signal conditioning circuit.
Although vibration signal can be monitored from X, Y, Z tri-directions, consider from monitoring convenience, vibration transducer is arranged on the top of shunting switch, the vibration signal of main monitoring shunting switch vertical direction.When shunting switch switches, monitor its vibration signal, this signal, after Acquisition Instrument collection, is undertaken analyzing, processing by computing machine, and carries out fault diagnosis.
In order to verify feasibility of the present invention; test as follows; experiment domestic application extremely widely M type load ratio bridging switch is tested, and shunting switch model is CMIII-500-63B-10193W (for the load ratio bridging switch manufacturing enterprise Shanghai Huaming Electric Appliance Equipment Co., Ltd of largest domestic produces).The basic parameter of this switch is in table 1.
Shunting switch basic parameter table tested by table 1
| Maximum rated by electric current (A) | 500 | The number of phases and connected mode | Three-phase Y connection |
| Maximum level voltage (V) | 3300 | Working position number | 19 |
| Amount electric pressure (kV) | 63 | The class of insulation | B |
| Specified level capacity (kVA) | 1400 | ? | ? |
Experimental provision also comprises acceleration vibration transducer, Buddhist nun's height data collecting instrument, microcomputer etc.Acceleration vibration transducer is directly installed on shunting switch top, and Buddhist nun's height Acquisition Instrument is used for collection and the record of signal, and PC then carries out data-storing, data processing and fault diagnosis.And demonstrate result in PC, the sample frequency of vibration signal is 50kHz.
In the vibration signal collected, the signal that the point of Energy maximum value gets 4096 points (about 82ms) backward after time delay 200 points (4ms) from time-domain signal is analyzed.
Normal shunting switch, the frequency spectrum of vibration signal can 4000Hz be roughly that boundary is divided into two parts, and lower than the region of 4000Hz referred to herein as comparatively low frequency range, the region higher than 4000Hz is called higher-frequency district.In comparatively low frequency range, the frequency of the signal that signal amplitude is maximum generally between 300 ~ 500Hz, and does not have the signal that amplitude is obviously large in 800 ~ 1000Hz interval.
When after tapping switch contact looseness fault, carry out signal analysis as stated above, between 800 ~ 1000Hz of frequency-region signal, newly increase the amount that an amplitude is obviously greater than other frequency signal amplitude, the amplitude of this radio-frequency component is not only greater than the signal maximum in former normal condition 300 ~ 500Hz interval, and is the amplitude larger (being generally maximum) of signal of all frequencies under malfunction.
After carrying out above-mentioned analysis to monitor signal, if find to occur the spectral line that amplitude obviously increases between frequency-region signal 800 ~ 1000Hz, this shunting switch substantially can be diagnosed out to there is contact slap fault; If the sample under normal condition can be had to contrast (historical data), the frequency of vibration frequency-region signal maximal value is originally between 300 ~ 500Hz, the current signal monitored newly increases the relatively very large characteristic signal of amplitude between frequency 800 ~ 1000Hz, not only original than this interval value of its maximal value is significantly increased, and is also greater than the amplitude of the signal between 300 ~ 500Hz.Then can reliably diagnose, there is contact slap fault in this shunting switch.
Accompanying drawing 3,4 is respectively in test under shunting switch normal condition and tapping switch contact looseness fault state, the spectrogram of vibration signal during shunting switch switching action.
Comparison diagram 3 and Fig. 4 can find, Fig. 3 time normal, and maximum amplitude part appears at 325Hz, amplitude about 0.0338 (ordinate is after the conversion such as vibration transducer, the relative magnitude of the signal obtained in signal sampler, lower same).The spectral line that obvious amplitude is very large is not had between 800 ~ 1000Hz., newly there is the spectral line of obvious amplitude maximum in Fig. 4 during fault, in this example, this spectral line amplitude reaches 0.076, and this spectral line amplitude is much larger than the amplitude of the maximum spectral line of original signal between 970Hz.
During different gear, the different operation conditions of shunting switch, the numerical value slightly difference of the amplitude of above-mentioned characteristic signal, this is because as a kind of mechanical switch, mechanical property in handoff procedure, vibration characteristics always have certain dispersiveness, but rule identical (namely different operating modes, different duties, after the looseness fault of contact, the signal of the obvious increase of an amplitude is always had to exist in 800 ~ 1000Hz interval).Vibration Condition (frequency domain figure) when Fig. 5-Figure 10 is the switching of shunting switch under different conditions.Wherein Fig. 5, Fig. 7 and Fig. 9 are the vibration signals spectrograph of normal condition, and Fig. 6, Fig. 8, Figure 10 are the vibration signals spectrograph of contact slap state.Visible, rule is the same.
Find after a large amount of measured test is carried out on the basis of theoretical analysis, above-mentioned feature has well repeated and regular.Demonstrate this feature and may be used for tapping switch contact slap fault diagnosis.
Claims (4)
1. a diagnostic method for power transformer on load tap changer contact looseness fault, is characterized in that:
One, Real-Time Monitoring is carried out to shunting switch switching action process vibrations, in the signal of monitoring, get the latter half of the main energy of vibration time-domain signal, and avoid Energy maximum value point in vibration time-domain signal;
Two, time-frequency transformation analysis is carried out;
Three, by analysis, the spectral line that amplitude within the scope of 800 ~ 1000Hz of signal frequency domain is larger is determined;
Four, compare, this spectral line comparatively shunting switch normal condition obviously increases, and shunting switch exists contact slap fault.
2. the diagnostic method of power transformer on load tap changer contact looseness fault according to claim 1, it is characterized in that: described tapping switch contact exists looseness fault, acceleration vibration transducer can be adopted to obtain the vibration signal of sub-connecting switch of transformer handoff procedure, after signal sampler collection, digital signal processing method is used to carry out analyzing and processing again, sample in conjunction with normal condition contrasts, diagnosis shunting switch fault, by monitoring and diagnostic result output on display accordingly.
3. the diagnostic device of a power transformer on load tap changer contact looseness fault, it is characterized in that: on sub-connecting switch of transformer, vibration transducer is installed, the output terminal of vibration transducer connects with the input end of signal conditioning circuit, the output terminal of signal conditioning circuit connects with the input end of Acquisition Instrument, Acquisition Instrument output terminal connects with the input end of signal processor, and the output terminal of signal processor is connected with display.
4. the diagnostic device of power transformer on load tap changer contact looseness fault according to claim 3, is characterized in that: described vibration transducer is arranged on the top of shunting switch, the vibration signal of main monitoring shunting switch vertical direction.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510812A (en) * | 2015-10-12 | 2016-04-20 | 国家电网公司 | Converter transformer tap switch condition monitoring system and non-stationary signal spectrum estimation method |
| CN106124973A (en) * | 2016-05-16 | 2016-11-16 | 国家电网公司 | Converter power transformer load ratio bridging switch on-line condition monitoring method |
| CN108490347A (en) * | 2018-05-24 | 2018-09-04 | 国网上海市电力公司 | A kind of breaker in extra high voltage arcing contact loosens the detection method of defect |
| CN109633431A (en) * | 2019-01-09 | 2019-04-16 | 国网江苏省电力有限公司电力科学研究院 | The load ratio bridging switch fault recognition method extracted based on vibration signal characteristics |
| CN110187268A (en) * | 2019-06-14 | 2019-08-30 | 国网江苏省电力有限公司 | Method, system and the terminal device of on-load tap changers of transformers data management |
| CN110422340A (en) * | 2019-08-29 | 2019-11-08 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Power supply unit, power supply system, cable loosen detection method and aircraft |
| CN113390591A (en) * | 2021-05-31 | 2021-09-14 | 广西电网有限责任公司电力科学研究院 | On-load tap-changer mechanical vibration detection system and method based on 5G network |
| CN113759197A (en) * | 2021-09-09 | 2021-12-07 | 国网上海市电力公司 | Power transformer state monitoring device and method |
-
2014
- 2014-09-11 CN CN201410461241.6A patent/CN104251953A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510812A (en) * | 2015-10-12 | 2016-04-20 | 国家电网公司 | Converter transformer tap switch condition monitoring system and non-stationary signal spectrum estimation method |
| CN106124973A (en) * | 2016-05-16 | 2016-11-16 | 国家电网公司 | Converter power transformer load ratio bridging switch on-line condition monitoring method |
| CN108490347A (en) * | 2018-05-24 | 2018-09-04 | 国网上海市电力公司 | A kind of breaker in extra high voltage arcing contact loosens the detection method of defect |
| CN109633431A (en) * | 2019-01-09 | 2019-04-16 | 国网江苏省电力有限公司电力科学研究院 | The load ratio bridging switch fault recognition method extracted based on vibration signal characteristics |
| CN109633431B (en) * | 2019-01-09 | 2021-07-09 | 国网江苏省电力有限公司电力科学研究院 | On-load tap-changer fault identification method based on vibration signal feature extraction |
| CN110187268A (en) * | 2019-06-14 | 2019-08-30 | 国网江苏省电力有限公司 | Method, system and the terminal device of on-load tap changers of transformers data management |
| CN110422340A (en) * | 2019-08-29 | 2019-11-08 | 中国商用飞机有限责任公司北京民用飞机技术研究中心 | Power supply unit, power supply system, cable loosen detection method and aircraft |
| CN113390591A (en) * | 2021-05-31 | 2021-09-14 | 广西电网有限责任公司电力科学研究院 | On-load tap-changer mechanical vibration detection system and method based on 5G network |
| CN113759197A (en) * | 2021-09-09 | 2021-12-07 | 国网上海市电力公司 | Power transformer state monitoring device and method |
| CN113759197B (en) * | 2021-09-09 | 2024-04-30 | 国网上海市电力公司 | Power transformer state monitoring device and method |
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