Micro computer monitoring power frequency high voltage test wave recording device
The utility model is a micro computer monitoring power frequency high voltage test wave recording device, belongs to high-potting and field of measuring technique.
Traditional power frequency high voltage experiment with measuring loop as shown in Figure 1.The voltage of measuring test specimen can adopt one of following three kinds of modes shown in Figure 1: mode (1) is to utilize testing transformer B
1The instrument winding that itself attaches inserts voltage table V
1Come reading numerical values, V
1Generally with common effective voltmeter.This pressure measurement mode adopts in most of middle-size and small-size electric enterprises; Mode (2) is to adopt high voltage potential transformer H
1, in the low pressure winding of mutual inductor and connect the crest voltage Table V
2Come reading; Mode (3) adopts high-voltage capacitive divider, in low-voltage arm and connect the crest voltage Table V
3Come reading.Mode (2) and mode (3) are the modes that the high-tension laboratory of large enterprise and specialty adopts usually.
Along with development of computer, the report of a small amount of more advanced power frequency high voltage test unit by computer monitor is arranged both at home and abroad, the lifting of switch deciliter and pressure regulator is controlled by computer in the loop, and the measurement of voltage also can be undertaken by computing machine.At this moment, voltage table V
3Or V
2Great majority adopt digital peak-reading voltmeter and are connected with computing machine by interface.Also can not adopt instrument, use the peak value rectification loop, be connected with computing machine then.The digital quantity of the former embodied on computer readable digital watch or analog quantity, the latter must be an analog quantity.Reading under the situation of analog quantity, computing machine is converted to digital quantity by A/D converter and shows on display screen then.The power frequency high voltage test unit is through being usually used in carrying out discharge in insulation test or flash test.The purpose of test this moment is to determine the insulation discharging voltage or the voltage breakdown of High-Voltage Electrical Appliances.The shortcoming of above-mentioned test unit be measure sparking voltage not accurate enough and dispersed bigger, this be because alternating current discharge voltage be actually relevant with instantaneous voltage.In high-potting standard GB311, execute high-potting outward and respond to high-potting all requiring to read crest voltage.The mode of above-mentioned measuring voltage (1) adopts effective voltmeter, and this obviously is inaccurate.Because mains voltage waveform often has harmonic wave to superpose on it, the ratio that makes peak value and effective value is a parameter.Also there are some problems in mode (2) and (3) though adopted peak-reading voltmeter.Because present peak value meter reading is the voltage peak that has reflected a certain period, no matter be that the indicating instrument or the digital peak value instrument of peak value rectification formula all is like this.The digital watch great majority all are to adopt the dual integration analog to digital conversion, and its sampling period is longer.Even and the very fast A/D converter of employing speed, the update cycle of demonstration also can not reach per second 50 times.Because if the display cycle is too fast, the reaction of people's eyes is not come, and in fact just can't see clearly yet.Have at present that the digital watch of some adjustable display cycles is the fastest also only to be shown twice or thrice a second, show being spaced apart more than power frequency tens cycles once this moment.As seen the still non-instantaneous voltage of the voltage that shows on the digital watch, but the same magnitude of voltage that belongs to a certain period of macroscopic view with indicating gauge.During the discharge in insulation test,, all require voltage evenly to rise till discharge no matter be manually-operated or computation.But because factors such as the limitation of pressure regulator performance or power-supply fluctuation occur on the test specimen voltage fluctuation being arranged sometimes.For the withstand voltage test of the tested transformer of the above neutral earthing device of 110kV, often replace the outer high pressure of executing with the induction high pressure.By intermediate transformer and tested transformer and the loop formed of distributed capacitance over the ground, because iron core is non-linear, make it the more difficult requirement of evenly boosting of satisfying, the voltage fluctuation on this moment test product is a common occurrence.If during voltage fluctuation, discharge, discharge moment people on instrument, read voltage may be inconsistent with the insulation discharging voltage of reality, general instrument presents slightly hysteresis.As long as someone thinks that indication that discharge the time reads instrument to maximum that value just can overcome the error that hysteresis brings, but reality also is far from it.Because often cause vibration after the discharge, the voltage peak of the several cycles in discharge back is often greater than the peak value of discharge place cycle.Some device has adopted the measure of locking digital watch after the discharge in insulation, but locking signal often just sends after discharge causes the overcurrent relay action, and this process has been some cycles after discharge, the also voltage of absence of discharge moment of blocked voltage this moment.In sum, carrying out withstand voltage or discharge in insulation when test, existing power frequency high voltage experimental measurement, operation are cumbersome, inefficiency and the sparking voltage or the breakdown voltage value that are difficult to accurately determine insulation, are necessary to improve.
The purpose of this utility model be exactly for overcome and solve that existing power frequency high voltage test unit is measured, test operation is cumbersome, inefficiency, measurement are inaccurate etc. shortcoming and problem, a kind of automaticity height of research and design, high efficiency, measurement are accurately and can record the micro computer monitoring power frequency high voltage test wave recording device of ripple automatically.
The circuit block diagram of micro computer monitoring power frequency high voltage test wave recording device and wiring diagram thereof as shown in Figure 2, capacitor C shown in Figure 2
1, C
2The equipment in voltage divider left side and experiment with measuring wiring thereof are conventional experiment with measuring devices, capacitor C
1, C
2The voltage divider right side is the utility model---the circuit block diagram of micro computer monitoring power frequency high voltage test wave recording device, it is electrically connected formation jointly by voltage changer VT, analog-digital conversion a/d card, microcomputer device CS, input/output interface circuit I/O card, and its interconnected relationship is: the input of voltage changer VT and C
1, C
2The circuit voltage divider that serial connection constitutes is electrically connected mutually and is electrically connected mutually with the analog-digital conversion a/d card by the voltage transformation output line, the analog-digital conversion a/d cartoon is crossed computer bus and is electrically connected mutually with microcomputer device CS, microcomputer device CS is by computer bus and input/output interface circuit I/O card connection, and the I/O cartoon is crossed the K switch in output line and conventionally test loop
1, K
2And pressure regulator T
1Be electrically connected mutually.The circuit principle of compositionality of this micro computer monitoring power frequency high voltage test wave recording device as shown in Figure 3, wherein: voltage changer VT is connected and composed by optical fiber and light-electricity and electricity-photoconverter by electro-optic crystal probe, (optional GCD-100 type), the A/D card is connected and composed by multi-channel electronic switch and analog to digital converter (optional ADG506 type and AD779 type), microcomputer device CS is by adopting software and hardware combining to realize the Industrial Control Computer (optional 586 types) and the display thereof of power frequency high voltage duration of test continuous sampling record ripple, printer connects and composes, and input/output circuitry is I/O card (optional 8255 type I/O interface modules) and the K switch of passing through its output signal line and conventionally test loop
1, K
2And pressure regulator T
1Be electrically connected mutually, thereby the change-over switch conducting is turn-offed and control pressure regulator voltage raising and reducing.A/D card and I/O card all patch patching on the notch in microcomputer.
Effect operation logic of the present utility model is as follows: during the power frequency high voltage test, whole process is by computer control, measurement, demonstration, timing, record ripple and control five functions and constantly carry out synchronously, wherein sampling and record ripple can be that per 20～80 μ S record a bit (is executed high pressure or responded to the supply frequency that high pressure adopted and decide on outer), measure (data processing), timing and send steering order that ripple is once weekly, screen display also is weekly that ripple is made once judgement, shows once when being in the display cycle of the setting of being in order.This process if do withstand voltage test, is then finished until withstand voltage timing, and the voltage for the treatment of test specimen is reduced to 50% of withstand voltage and just finished; If do discharge test or when doing withstand voltage test, discharge, then in one or two cycle that discharge takes place, finish, this moment, sparking voltage should be as the criterion with wave form analysis.Generally speaking, as each cycle voltage waveform stable (in boost phase or visible ascendant trend slightly) before discharging, then with the crest voltage of the last cycle that discharges sparking voltage as insulation.The equipment in capacitive divider left side is conventional test loop among Fig. 2, can further describe, and the equipment on its right side promptly is the utility model device.Wherein: voltage changer (VT) is C
1, C
2The power-frequency voltage that capacitive divider is told is transformed into the input voltage that is suitable for modulus converter A/D, waveform then with C
2On waveform identical.Require this transducer must be high input impedance and also should be much larger than C
2Capacitive reactance.The effect of isolation be should have simultaneously concurrently, modulus converter A/D and computing machine damaged because of counterattack when avoiding discharging.Modulus converter A/D should adopt more than 12, and its sample rate is enough fast, reaches suitable precision with the measurement that guarantees the power frequency peak value.Computing machine CS comprises microcomputer, display and a printer.Wherein microcomputer must be at a high speed, finishes multinomial functions such as record ripple, data processing, demonstration and control simultaneously otherwise be difficult to satisfy in a cycle.Interface circuit (I/O) be used to control the voltage up-down of pressure regulator and switch deciliter.Computer software programs are according to not only satisfying withstand voltage test but also can satisfy two kinds of function designs of discharge test, and its software program flow process block diagram as shown in Figure 4.It matches with this device, just can all measure primary voltage by each cycle of realization in the power frequency high voltage test, and the voltage waveform before and after the continuous recording discharge.
The utility model is compared with traditional power frequency high voltage experiment test device, has following advantage and beneficial effect: (1) is because the utility model adopts microcomputer Automatic Control and measurement.Measuring voltage ripple is weekly carried out once, and measurement, demonstration, timing, record conformance control are carried out synchronously.When discharge in insulation, it can record down a series of waveforms before and after the discharge, and the gauge tap separating brake, the step-down excision.Since can record from normal condition to the waveform that some cycles that discharge experienced take place, the worthwhile right conventional voltage table than macroscopic view peak value of a certain period of reflection of the sparking voltage that draws is accurate in view of the above.Because the instantaneous voltage value that is applied in the insulation was depended in discharge in insulation originally.The power frequency high voltage that all traditional power frequency high voltage test units are measured all is the peak value of a certain period.The utility model adopts computing machine to monitor automatically, and hardware and software is suitably cooperated, and can directly record the voltage waveform of several cycles before and after the discharge, thereby can accurately determine the sparking voltage that insulate; (2) because process of the test of the present utility model is controlled by computer software programs, all realized robotization such as the adjustment of the rate of rise, withstand voltage timing, switch deciliter etc., thereby also improved work efficiency; (3) the utility model helps testing analysis of abnormal.What is called is meant the electric voltage exception fluctuation unusually, and one of them may be that the electric power network disturbance causes, also might be that the test loop parametrical nonlinearity causes.For instance, for the induction high-potting of the above transformer of 110kV, because line end and neutral point different insulative level replace the outer high pressure of executing with the induction high pressure, test is to pursue to carry out mutually, and high-pressure measurement mechanism is in tested phase line end, and line end connects protection ball crack simultaneously.In the process of boosting, hear sometimes and see that test specimen punctures with the copper ball discharge and take place simultaneously, voltage table fall after rising (fall is because the switch automatic trip of discharge back).Because process takes place suddenly in a flash at certain; the crest voltage meter reading that the manual read gets is likely inaccurate; and to the explanation of this process also exist two kinds may: first kind of explanation is to think; boost through intermediate transformer in this induced test loop; because intermediate transformer is different with tested transformer degree of saturation under different voltages; belong to nonlinear element; adopt 100～200 all power supplys to make the capacity current of test specimen load bigger during induced test; if loop parameter is near resonance in the process of boosting; cause that then voltage rises rapidly; though protection ball crack generally is adjusted to 1.15～1.2 times of withstand voltage; but voltage surpasses this value ball crack still to discharge; the discharge back further punctures tested transformer owing to vibration causes voltage higher.Think that thus the original insulation of transformer does not have defective, just the testing equipment parameter cooperates bad this afterclap that causes; Transformer insulated defectiveness is thought in second kind of explanation, and test product is not breakdown when voltage reaches or rise to withstand voltage, causes vibration after the puncture, and voltage further raises, thereby makes ball-gap discharge.This process equally also is to take place in the blink in one or two week, and sees that equally voltage table falls after rising.In the high-power transformer test, the probability that protection copper ball and test specimen discharge simultaneously is very high.If adopt this micro computer monitoring wave recording device, as long as waveform before and after the discharge at a glance, just character that immediately can deterministic process belongs to the former or the latter.As belong to the former, should see voltage weekly ripple increase progressively very soon, and the voltage of discharge cycle reaches the protection voltage of copper ball, is that copper ball discharges prior to test specimen at this moment.As belong to the latter, then to raise should be slowly and steadily to the voltage of each waveform, and the voltage of the cycle that begins to discharge is lower than copper ball protection voltage, only is that thereafter vibration superpotential just causes the copper ball discharge; (4) this device as be used to has the High-Voltage Electrical Appliances test of interior insulation (oil-immersed type transformer, oilpaper sleeve pipe, solid are casting insulated etc.), record fault waveform help to carry out more analysis of science and judge to puncturing character.At this moment, this device will be recorded down the voltage and current waveform simultaneously, and should record following 50 cycles or more Wave datas at least.The voltage grading if see current increase from fault waveform does not have significantly sudden change, and this should be thermal breakdown but not electric breakdown.The fault waveform that punctures such as transformer breakdown between adjacent turns and major insulation also will be different in addition.Therefore, the utility model might be started a technology of judging various nature of troubles with the power frequency fault waveform; (5) this device can with the supporting use of original power frequency high voltage test unit, make original device upgrade to the power frequency high voltage equipment that computing machine is automatically monitored the record ripple, its technical feature is improved greatly, enable to be applicable to the high-tension laboratory of power test department and the factory and enterprise of producing High-Voltage Electrical Appliances, power transformer product.
Below Figure of description is further specified as follows: Fig. 1 is traditional power frequency high voltage experiment with measuring loop; Fig. 2 is the circuit block diagram and the experiment with measuring wiring diagram thereof of micro computer monitoring power frequency high voltage test wave recording device; Fig. 3 is the circuit principle of compositionality figure of this micro computer monitoring power frequency high voltage test wave recording device; Fig. 4 is the microcomputer software program circuit block scheme of this micro computer monitoring power frequency high voltage test unit; Fig. 5 is example 1 10 cycle oscillograms that the first time, discharge test was recorded; Fig. 6 is the oscillogram of BC-35 cover tube discharge the last week and discharge place cycle for example 2 test specimens; Fig. 7 is two cycle oscillograms before and after the ball-gap discharge in the example 2.Among each figure: K
1, K
2Be switch, T
1Be pressure regulator, B
1Be HT testing transformer, R
1Be water resistance, BSP
1Be product to be tested, C
1, C
2Be voltage-dividing capacitor, H
1Be voltage transformer (VT), V
1Be common effective voltmeter, V
2, V
3Be peak-reading voltmeter, VT is a voltage changer, and A/D is an A/D converter, and CS is a microcomputer device, and I/O is the input/output interface circuit.CYCLE is the cycle, and SCALE is an engineer's scale.
This practical embodiment can be as follows: (1) is by shown in Figure 3, choose some components and parts, for example: the optional GCD-100 type of voltage changer VT, the optional 8255 type I/O interface modules of A/D card, the I/O card that optional ADG506 electronic multi-channel switch of A/D card and AD779 pattern number conversion module connect and compose, optional 586 Industrial Control Computers of microcomputer device CS and supporting display and printer thereof.Then the A/D card of choosing, I/O clamping are inserted in patching on the notch of 586 microcomputers; (2) by shown in Figure 2 and connection is installed, just can finish the connection of measurement of the present utility model, test loop by the described annexation of top instructions; (3) by shown in Figure 4, the monitoring software program of establishment micro computer monitoring power frequency high voltage test.Working procedure just can finely be measured and high-potting on computers then.The inventor shows this device of use through a large amount of tests, can can both realize robotization to the adjustment of the rate of rise, withstand voltage timing, switch on and off etc., and can record the waveform before and after the discharge down when discharge or puncture take place test specimen, this has not only improved work efficiency, and measurement data is accurate, the reliability height.Following inventor is listed below two examples and is illustrated:
Example 1: the test site is at electric power institute of South China Science ﹠ Engineering University high-tension laboratory.The same Fig. 2 of its test connection.Testing transformer B wherein
1Be 250kV, 1A HT testing transformer, pressure regulator T
1Be the 250kVA moving coil voltage regulator.The C of capacitive divider
1=768pf, C
2=0.9788 μ f, its working voltage is no more than 150kV, voltage changer VT adopts the GCD-100 type optical fiber field intensity voltage table of being produced by power test research institute of northwest electricity management board, this voltage table can directly show alternating voltage effective value (digital) on the one hand, exportable again real-time AC signal, this signal are delivered to the A/D input port of computing machine and are used as recording ripple in real time; A-D converter A/D adopts the AD779 of U.S. A/D company, 14 bit resolutions, and the highest sample frequency is 100kHz, and I/O adopts 8255 parallel input/output interfaces, and computing machine adopts 586 Industrial Control Computers.Software programming and step are referring to block diagram shown in Figure 4.Wherein except that record ripple, data processing, timing, control buck, demonstration etc. were partly worked out with 8086 assembly language, all the other were all with the higher level lanquage establishment, and whole procedure is moved after can being compiled into the EXE file.
The test specimen BSP that this is routine
1It is GW-10 type 10kV high voltage isolator.Proceedings applies on the magnitude of voltage 50% promptly to begin to record continuously ripple in expectation, sampling interval 80 μ S, write down 2500 sample values of 10 cycles, wash out the sample value of first cycle since the 11st cycle, later on one by one with newly towards old, so have the data of up-to-date 10 cycles in the calculator memory all the time.When each generation was discharged, computer search had sudden change to the curtage waveform, and programmed control is excised switch immediately and made the pressure regulator step-down.Therefore, the record ripple promptly stops behind the cycle of undergoing mutation.After test was finished, other had special program that the form of the data of 10 cycles with waveform shown on computer screen, also can print on printer.10 cycles that table 1 is recorded for discharge test for the first time apply voltage peak (with the effective value scale), the printout waveform of each cycle of correspondence is as shown in Figure 5.From table 1 and Fig. 5 as seen, it is more stable and little on the rise (this is because when doing dried discharge test that the voltage of 9 cycles before the discharge takes place, pressure regulator is in lasting ascent stage), during discharge because test loop parameter causes the test specimen terminal voltage higher-order of oscillation so that generation is restriked for 4 times.The positive and negative voltage of discharge place cycle all rises.Obviously the sparking voltage value of test specimen should be with the discharge voltage of the last week, and promptly 68.63kV is as the criterion.This routine test specimen has carried out dried discharge test 10 times, and similar record ripple is also made in all the other 9 times discharges, always has 100 waveforms and prepares against inquiry with the document form data deposit.
10 cycles before the table 1:10kV high voltage isolator power-frequency discharge apply magnitude of
voltage
| | 5 | 6 | 7 | 8 | 9 | 10 | 1 | 2 | 3 | 4 |
| Magnitude of voltage (kV) | 68.05 | 68.22 | 67.88 | 67.99 | 68.56 | 68.40 | 68.60 | 68.81 | 68.63 | Discharge |
Example 2: this routine testing ground is at Guangzhou power equipment factory high-tension laboratory, its power frequency testing transformer B
1Be two 200kV tandems (always exporting 400kV), high pressure rated current 1A: pressure regulator T
1Be induction voltage regulator; 1000 times of capacitive divider intrinsic standoff ratios; Same GCD instrument and the computer A/D interface of adopting.Test specimen BSP
1Be by BC-35 (35kV sleeve pipe).Table 2 is the magnitude of voltage that applies of preceding 10 cycles of discharge.
10 cycles before the table 2:35kV sleeve pipe power-frequency discharge apply magnitude of
voltage
| | 6 | 7 | 8 | 9 | 10 | 1 | 2 | 3 | 4 | 5 |
| Magnitude of voltage (kV) | 182.6 | 182.8 | 182.6 | 182.5 | 182.6 | 182.3 | 183 | 182.7 | 183.1 | Discharge |
10 cycle data of test have been deposited for future reference, and the oscillogram of wherein discharge the last week and discharge place cycle as shown in Figure 6.This routine sparking voltage decidable is 183.1kV, because this plant parameter cooperation is preferable, test specimen discharge back damped oscillation decays rapidly, does not cause any superpotential in the test specimen termination.
Also carried out the discharge test in 0.5 meter ball crack in this factory.The magnitude of voltage of 10 cycles before its discharge and the waveform of two cycles are respectively as table 3 and shown in Figure 7.
10 cycles before the power-frequency discharge of table 3:0.5 rice ball crack apply magnitude of
voltage
| | 8 | 9 | 10 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Magnitude of voltage (kV) | 229.4 | 228.8 | 229.8 | 229.6 | 229.7 | 230.0 | 229.4 | 230.2 | Discharge | Discharge |
This routine ball-gap discharge voltage decidable is 230.2kV, because discharge place cycle and phase of wave ratio the last week, positive negative peak is significantly sudden change not, and computing machine is proceeded the 7th cycle record ripple in the instruction that the 6th cycle trips and stops to record ripple.Therefore record the waveform of two cycles after the discharge of this example.From oscillogram as seen, ball crack power-frequency discharge is very regular rapid damping damped oscillation waveform.
