CN217060394U - Test device for measuring partial discharge of electromagnetic voltage transformer - Google Patents
Test device for measuring partial discharge of electromagnetic voltage transformer Download PDFInfo
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- CN217060394U CN217060394U CN202220351145.6U CN202220351145U CN217060394U CN 217060394 U CN217060394 U CN 217060394U CN 202220351145 U CN202220351145 U CN 202220351145U CN 217060394 U CN217060394 U CN 217060394U
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Abstract
The utility model provides a measure electromagnetic type voltage transformer partial discharge test device reduces test instrument's use, has reduced test cost, can improve maintenance efficiency, reduces the maintenance cost and saves test time simultaneously. The device comprises a variable frequency power supply, a mutual inductor, a detection impedance and a partial discharge instrument which are connected in sequence; the mutual inductor comprises a plurality of low-voltage windings and a plurality of high-voltage windings, the low-voltage windings of the mutual inductor are connected with the output end of the variable-frequency power supply, the high-voltage windings of the mutual inductor are connected with the input end of the detection impedance, and the output end of the detection impedance is connected with the detection end of the partial discharge instrument. Partial discharge test device reduced the use of instrument, reduced test cost, can improve maintenance efficiency, reduce the maintenance expense and save test time simultaneously.
Description
Technical Field
The utility model relates to a generator export electromagnetic type voltage transformer fault test and failure diagnosis technical field specifically are a measure electromagnetic type voltage transformer partial discharge test device.
Background
The voltage transformer is an important special transformer in an electric power system, and mainly converts high voltage into low voltage which can be directly measured by an instrument in proportion, and the instrument is configured to measure by utilizing the transformation ratio relation of the transformer. The power supply and the signal are provided for devices such as relay protection, electric energy metering, automatic control, signal indication and the like. The voltage transformer has a similar structural principle to a transformer, namely, a primary winding and a secondary winding which are insulated from each other are wound on an iron core of a closed loop. The 20kV voltage class transformer produced in China mostly adopts an epoxy resin pouring insulation structure, and mainly measures insulation resistance and alternating current withstand voltage when regular test and inspection are carried out. The quality of the insulating performance of the transformer is an important factor for judging the condition of the transformer. Partial discharge defects are difficult to find by using a traditional insulation test method, and insulation is damaged by a 1min alternating current withstand voltage test, so that the later operation performance of equipment is influenced. In recent years, 50% of voltage transformer accidents in China are accidents caused by short circuit between turns or segments under normal operation, and the reasons are also partial discharge. Research proves that partial discharge is one of the main reasons for causing insulation damage of high-voltage electrical equipment, weak partial discharge can generate an accumulation effect, insulation defects can be gradually enlarged, finally, breakdown, explosion and other faults occur, once the faults occur, the safe operation of the whole system can be seriously damaged, and huge economic loss is caused.
At present, the detection method of the electromagnetic voltage transformer mainly comprises insulation test, direct resistance test, alternating current withstand voltage and partial discharge measurement. The conventional partial discharge test mainly adopts a different test scheme, the first scheme is a one-time pressurization scheme, and the scheme needs an independent partial discharge-free transformer for boosting. The second scheme is a secondary induction pressurization scheme, a coupling capacitor without partial discharge is required to be added and connected with the high-voltage winding A of the mutual inductor in parallel, and partial discharge signals are measured through the coupling capacitor. The two test schemes require more and heavy test instruments, and increase the test cost and the test time.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem that exists among the prior art, the utility model provides a measure electromagnetic type voltage transformer partial discharge test device reduces test instrument's use, has reduced test cost, can improve maintenance efficiency, reduces the maintenance cost and saves test time simultaneously.
The utility model discloses a realize through following technical scheme:
a test device for measuring partial discharge of an electromagnetic voltage transformer comprises a variable frequency power supply, the transformer, a detection impedance and a partial discharge instrument which are sequentially connected;
the transformer comprises a plurality of low-voltage windings and a plurality of high-voltage windings, the low-voltage windings of the transformer are connected with the output end of the variable-frequency power supply, the high-voltage windings of the transformer are connected with the input end of the detection impedance, and the output end of the detection impedance is connected with the detection end of the partial discharge instrument.
Preferably, the low-voltage winding comprises a tested low-voltage winding and a non-tested low-voltage winding, wherein the tested low-voltage winding is connected with the output end of the variable-frequency power supply through an isolation transformer, and the tail end of the high-voltage winding is connected with the input end of the detection impedance.
Preferably, the non-tested low voltage winding of the transformer is reliably grounded.
Preferably, the head end of the high-voltage winding is connected with a voltage-equalizing cap.
Preferably, the head end of the high-voltage winding is connected with a calibration pulse generator, and a ground terminal of the calibration pulse generator is reliably connected with a ground terminal of the detection impedance.
Preferably, a broadband amplifier is arranged between the detection impedance and the partial discharge instrument.
Preferably, the low-voltage winding of the mutual inductor is reliably connected with the output end of the variable-frequency power supply through a low-voltage signal wire.
Preferably, the transformer is a dry-type voltage transformer, a cast insulation voltage transformer, an oil-immersed voltage transformer or a gas insulation voltage transformer.
Compared with the prior art, the utility model discloses following profitable technological effect has:
the utility model provides a pair of measure electromagnetic type voltage transformer partial discharge test device to exist not enough among the current mutual-inductor partial discharge test method, utilizes mutual-inductor self winding structural feature test partial discharge, through on the pressurized basis of secondary response, no longer uses independent coupling capacitor, but will detect and measure after the impedance is direct to establish ties with the high voltage winding of mutual-inductor. The variable frequency power supply provides excitation voltage for a low-voltage winding of the mutual inductor, and high voltage is generated by utilizing the transformation ratio of the mutual inductor. Under the high voltage required by regulations, due to charge exchange generated by partial discharge, high-frequency current pulses are generated, voltage pulses are generated through a detection impedance connected with the tail end of a high-voltage winding of the mutual inductor, and the voltage pulses are measured by an partial discharge instrument. Partial discharge test device reduced the use of instrument, reduced test cost, can improve maintenance efficiency, reduce the maintenance expense and save test time simultaneously.
Drawings
Fig. 1 is the structure schematic diagram of the partial discharge test device of the present invention.
In the figure: 1. a variable frequency power supply; 2. an isolation transformer; 3. a pressure equalizing cap; 4. a mutual inductor; 5. detecting impedance; 6. a partial discharge instrument; 7. the pulse generator is calibrated.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The present invention will be described in further detail with reference to the accompanying drawings:
as shown in fig. 1, the utility model provides a test device for measuring partial discharge of an electromagnetic voltage transformer, which comprises a variable frequency power supply 1, a transformer 4, a detection impedance 5 and a partial discharge instrument 6 which are connected in sequence;
the low-voltage winding 1a1n of the mutual inductor 4 is connected with the output end of the variable-frequency power supply 1, the tail end X of the high-voltage winding of the mutual inductor 4 is connected with the input end of the detection impedance 5, and the output end of the detection impedance 5 is connected with the detection end of the partial discharge instrument 6.
The utility model provides a pair of measure electromagnetic type voltage transformer partial discharge test device to exist not enough among the 4 partial discharge test methods of current mutual-inductor, utilizes mutual-inductor 4 self winding structural feature test partial discharge, through on the pressurized basis of secondary response, no longer uses independent coupling capacitor, but will detect impedance 5 and directly establish ties in mutual-inductor 4's high voltage winding tail end X department and measure. The low-voltage winding 1a1n of the transformer 4 is provided with excitation voltage by the variable-frequency power supply 1, and high voltage is generated by the transformation ratio of the transformer 4. Under the high voltage required by regulations, due to charge exchange generated by partial discharge, high-frequency current pulses are generated, voltage pulses are generated through a detection impedance 5 connected with the tail end X of a high-voltage winding of a mutual inductor 4, and the voltage pulses are amplified by a proper broadband amplifier and then measured by a partial discharge instrument 6. Partial discharge test device reduced the use of instrument, reduced test cost, can improve maintenance efficiency, reduce the maintenance expense and save test time simultaneously.
The transformer 4 comprises a plurality of low-voltage windings and a plurality of high-voltage windings, the low-voltage windings comprise tested low-voltage windings and non-tested low-voltage windings, the tested low-voltage windings are connected with the output end of the variable-frequency power supply 1 through the isolation transformer 2, and the tail end of the high-voltage windings is connected with the input end of the detection impedance 5.
Wherein, the head end A of the high-voltage winding is connected with the voltage-sharing cap 3 and is connected to the calibration pulse generator 7 through the voltage-sharing cap 3.
Wherein the non-tested low-voltage winding of the mutual inductor 4 is reliably grounded.
Wherein the ground terminal of the detection impedance 5 is reliably grounded.
Further, a broadband amplifier is arranged between the detection impedance 5 and the partial discharge instrument 6, and the broadband amplifier can amplify the generated voltage pulse, so that the partial discharge instrument 6 can conveniently measure and observe.
Preferably, the transformer 4 is a dry-type voltage transformer, a cast-insulation voltage transformer, an oil-immersed voltage transformer or a gas-insulation voltage transformer.
The utility model provides an in the embodiment variable frequency power supply 1's output and isolation transformer 2's input be connected, isolation transformer 2's output and mutual-inductor 4's low voltage winding 1a1n are connected, form excitation induction loop. The voltage-sharing cap 3 is connected with the head end A of the high-voltage winding of the mutual inductor 4, the tail end X of the high-voltage winding of the mutual inductor 4 is connected with the input end of the detection impedance 5, and the output end of the detection impedance 5 is connected with the input end of the partial discharge instrument 6 to form a partial discharge measurement loop.
In this embodiment, a variable frequency power supply is used as an example, and the test apparatus for measuring partial discharge of an electromagnetic voltage transformer of the present invention is described.
Implement the test device of the utility model, the concrete implementation process is as follows:
1) carrying out preparation work before the partial discharge test of the mutual inductor 4, and entering the step 2) after all the early preparation work is finished;
2) and opening the variable frequency power supply tester, and reliably and firmly connecting the test wire to the low-voltage winding terminal 1a1n of the mutual inductor 4. The detection impedance 5 is connected in series with the tail end X of the high-voltage winding of the mutual inductor 4 and then grounded, and a signal wire of the detection impedance 5 is connected into a partial discharge instrument 6. Entering step 3);
3) the calibration pulse generator 7 is turned on and its output gear is adjusted to 500pC, at which time the measurement data is viewed on the partial discharge meter. By adjusting the gain, the measurement data was made to be 500 pC. The square wave power supply output gear is adjusted to be 100pC, and the measured data checked on the partial discharge instrument 6 at the moment is 100 pC. The partial discharge test loop is checked, the calibration pulse generator 7 is removed after the check is finished, and the step 4) is carried out;
4) turning on a power switch of the variable frequency power supply tester, adjusting the test frequency to 50Hz, testing the no-load current before testing, reducing the test voltage to 0V after the no-load current is tested, adjusting the test frequency to 150Hz, and entering the step 5);
5) and slowly controlling a boosting program of the variable frequency power supply, observing the measured value of the partial discharge instrument in the process of boosting the voltage, and stopping the test immediately when the measured value is abnormal to perform inspection and analysis. At a voltage level of 1.1Um/√ 3, for one minute, the partial discharge amount was observed, and a continuous level of the partial discharge amount not more than 100pC was acceptable. After the test is finished, the test voltage is reduced to 0V. Adjusting the test frequency to 50Hz, and entering the step 6);
6) and (4) testing the no-load current after the test, reducing the test voltage to 0V after the no-load current test is finished, turning off the power supply, and fully discharging the mutual inductor 4.
The specific operation process of the step 1) is as follows:
11) and (4) completely removing the high-voltage side lead, the fuse and the low-voltage side secondary wire of the tested mutual inductor 4. And the removed high-voltage lead is far away from the body of the tested mutual inductor 4 as far as possible. The n-terminal of the non-tested winding is directly grounded.
12) A220V power supply for test is prepared, and the variable frequency power supply tester and the partial discharge instrument 6 are reliably grounded.
The specific operation process of the step 2) is as follows:
21) the voltage-equalizing cap 3 is worn at the head end A of the high-voltage winding, the input end of the detection impedance 5 is connected in series at the tail end X of the high-voltage winding, and the grounding terminal of the detection impedance 5 is reliably grounded.
22) The output end of the detection impedance 5 is connected to the partial discharge instrument 6.
23) The variable frequency power supply 1 is connected with an isolation transformer 2, and then the output end of the isolation transformer 2 is connected with a low-voltage winding 1a1n of a mutual inductor 4.
The specific operation process of the step 3) is as follows:
31) and the output end of the calibration pulse generator 7 is reliably connected with the head end A of the high-voltage winding of the mutual inductor 4 through a special shielded wire and is suspended.
32) The ground terminal of the calibration pulse generator 7 is reliably connected to the ground of the detection impedance 5.
The specific operation process of the step 4) is as follows:
41) the n end of the low-voltage winding of the mutual inductor 4, which is not the tested winding, is reliably grounded.
42) The no-load current was measured at 1.0 times, 1.5 times, and 1.9 times, respectively. The excitation current test result meets the requirements of the regulations.
The specific operation process of the step 5) is as follows:
51) before boosting, the safety distance around the mutual inductor 4 is confirmed again, and the mutual inductor 4 is ensured to be in an independent space.
52) During the test, the release amount was carefully observed. Note that the body of the transformer 4 has no abnormal sound.
53) The continuous level of the partial discharge amount during the test at a voltage of 1.1Um/√ 3 is not more than 100 pC.
54) During the test at a voltage of 1.1Um (if necessary), the continuous level of the partial discharge quantity was not more than 500 pC.
55) At a voltage of 1.1Um/√ 3, partial discharges do not exhibit a tendency to continue to grow, and higher amplitude pulses that occur by chance may not be accounted for.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. The embodiments described in this specification are to be considered exemplary only, with a true scope of the application being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of protection of the invention is defined by the claims.
Claims (8)
1. A test device for measuring partial discharge of an electromagnetic voltage transformer is characterized by comprising a variable frequency power supply (1), a transformer (4), a detection impedance (5) and a partial discharge instrument (6) which are sequentially connected;
the transformer (4) comprises a plurality of low-voltage windings and a plurality of high-voltage windings, the low-voltage windings of the transformer (4) are connected with the output end of the variable-frequency power supply (1), the high-voltage windings of the transformer (4) are connected with the input end of the detection impedance (5), and the output end of the detection impedance (5) is connected with the detection end of the partial discharge instrument (6).
2. The test device for measuring the partial discharge of the electromagnetic voltage transformer according to claim 1, wherein the low voltage winding comprises a tested low voltage winding and a non-tested low voltage winding, wherein the tested low voltage winding is connected with the output end of the variable frequency power supply (1) through an isolation transformer (2), and the tail end of the high voltage winding is connected with the input end of the detection impedance (5).
3. A test device for measuring partial discharge of an electromagnetic voltage transformer according to claim 2, characterized in that the non-tested low-voltage winding of the transformer (4) is reliably grounded.
4. The test device for measuring the partial discharge of the electromagnetic voltage transformer according to claim 2, wherein a voltage-equalizing cap (3) is connected to the head end of the high-voltage winding.
5. The test device for measuring the partial discharge of the electromagnetic voltage transformer according to claim 2, wherein the head end of the high-voltage winding is connected with a calibration pulse generator (7), and the grounding terminal of the calibration pulse generator (7) is reliably connected with the grounding end of the detection impedance (5).
6. The testing apparatus for measuring partial discharge of an electromagnetic voltage transformer according to claim 1, wherein a broadband amplifier is disposed between the detection impedance (5) and the partial discharge instrument (6).
7. The testing device for measuring the partial discharge of the electromagnetic voltage transformer according to claim 1, wherein the low-voltage winding of the transformer (4) is reliably connected with the output end of the variable-frequency power supply (1) through a low-voltage signal wire.
8. The testing device for measuring the partial discharge of the electromagnetic voltage transformer according to claim 1, wherein the transformer (4) is a dry voltage transformer, a cast insulation voltage transformer, an oil-immersed voltage transformer or a gas insulation voltage transformer.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220351145.6U CN217060394U (en) | 2022-02-21 | 2022-02-21 | Test device for measuring partial discharge of electromagnetic voltage transformer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220351145.6U CN217060394U (en) | 2022-02-21 | 2022-02-21 | Test device for measuring partial discharge of electromagnetic voltage transformer |
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| CN202220351145.6U Active CN217060394U (en) | 2022-02-21 | 2022-02-21 | Test device for measuring partial discharge of electromagnetic voltage transformer |
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