CN102129032B - Transformer on-load tapping switch tester - Google Patents
Transformer on-load tapping switch tester Download PDFInfo
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- CN102129032B CN102129032B CN 201010584656 CN201010584656A CN102129032B CN 102129032 B CN102129032 B CN 102129032B CN 201010584656 CN201010584656 CN 201010584656 CN 201010584656 A CN201010584656 A CN 201010584656A CN 102129032 B CN102129032 B CN 102129032B
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Abstract
The invention discloses a transformer on-load tapping switch tester. The tester is of a circuit module structure that: a filter circuit is connected with a constant current source circuit and a reference voltage circuit respectively, the reference voltage circuit is connected with the constant current source circuit, and the constant current source circuit is connected with a data acquiring and processing circuit. The comprehensive measuring instrument for measuring and analyzing electric performance indexes of a transformer on-load tapping switch in a power system can realize measurement of parameters of transition time, transition waveform, transition resistance, three-phase synchronism and the like of the on-load tapping switch, and has the advantages of convenience in use, light weight, good interference resistance and high precision.
Description
Technical field
The present invention relates to a kind of for the composite measurement instrument of measuring and analyze electric system on-load tap changers of transformers electricity function index.
Background technology
The measurement of load ratio bridging switch is divided into no winding and has winding to measure two kinds, and namely bringing onto load (transformer) and bringing onto load are not measured.No winding measurement is mainly used in the measurement of dispatching from the factory when switch is produced, when having winding then to be used for switch maintenance.Because when load ratio bridging switch uses and transformer be connected as a single entity, switch and transformer are separately pretty troublesome during measurement, have winding to measure so adopt.Have winding to measure owing to added Transformer Winding in the loop, and Transformer Winding is perception, in handoff procedure, can hinders the variation of loop current, produce vibration, make the voltage and current signal that records inaccurate, cause Rx inaccurate.Therefore, to being arranged, measures winding, usually adopt the method that adds current source at present, the influence of transformer coil inductance to measuring when eliminating the switch switching with constant current, but the present of home make tester accuracy in this aspect generally is not very high, add that tester output result directly shows the waveform that transition resistance and transit time are formed, by the own moving cursor of user of service, to check actual transition resistance and transit time, because the otherness of personnel's reading causes the measuring error to load ratio bridging switch transition resistance and transit time bigger.
Summary of the invention
Purpose of the present invention provides a kind of easy to use, in light weight, good in anti-interference performance, precision high a kind of for transformer on-load tap changer tester just in order to overcome the defective that above-mentioned prior art exists.
The objective of the invention is to realize by following technical solution.
Circuit module structure of the present invention is, adopts filtering circuit to be connected with constant-current source circuit, reference voltage circuit respectively, and reference voltage circuit is connected with constant-current source circuit again, and constant-current source circuit is connected with treatment circuit with data acquisition again.
H bridge and high-frequency transformer that constant-current source circuit of the present invention is made up of field effect transistor are formed; Filtering circuit by ac filter and superpotential suppress, DC filtering forms, wherein ac filter partly contains two coils on the ferrite; Reference voltage circuit is made up of voltage chip LM399 and amplifier LM258; Data acquisition and treatment circuit keep chip LF298 and AD analog to digital conversion AD7714 to form by sampling.Constant-current source circuit partly is output as the DC current of 1A.
The present invention can be used in the composite measurement instrument of measuring and analyzing on-load tap changers of transformers electricity function index in the electric system, can realize transit time, transition waveform, transition resistance, the isoparametric measurement of three-phase synchronism to load ratio bridging switch, with having easy to use, in light weight, good in anti-interference performance, precision height.
Description of drawings
Fig. 1 is general structure block diagram of the present invention;
Fig. 2 is constant-current source circuit figure;
Fig. 3 is filtering circuit figure;
Fig. 4 is reference voltage circuit figure;
Fig. 5 is data acquisition and treatment circuit figure;
Fig. 6 is the oscillogram of transition resistance and transit time.
Embodiment
As shown in Figure 1, transformer on-load tap changer tester of the present invention, its circuit module structure are to adopt filtering circuit to be connected with constant-current source circuit, reference voltage circuit respectively, reference voltage circuit is connected with constant-current source circuit again, and constant-current source circuit is connected with treatment circuit with data acquisition again.
Constant-current source circuit is made up of H bridge and high-frequency transformer that field effect transistor is formed as shown in Figure 2; Filtering circuit as shown in Figure 3 by ac filter and superpotential suppress, DC filtering forms, wherein ac filter partly contains two coils on the ferrite; Reference voltage circuit is made up of voltage chip LM399 and amplifier LM258 as shown in Figure 4; Data acquisition and treatment circuit keep chip LF298 and AD analog to digital conversion AD7714 to form by sampling as shown in Figure 5.Constant-current source circuit partly is output as the DC current of 1A.Output transition resistance, transit time waveform is illustrated in figure 6 as spill.
Ultimate principle of the present invention is: export the DC current of 1A to the load ratio bridging switch of transformer by constant-current source circuit, simultaneously from obtaining its d. c. voltage signal from the load ratio bridging switch joint, sample then, operation such as maintenance, AD conversion, demonstration, the inter-process by single-chip microcomputer directly shows its transition resistance, transition current, three-phase synchronism and waveform.
Circuit theory of the present invention is:
1. constant-current source circuit
Constant-current source circuit is regulated electric current to 1A automatically by the mode of closed-loop control, its concrete control method: DC voltage is carried on the H bridge of 4 metal-oxide-semiconductors compositions, receive in the loop of LRC by transformer and VD1, VD2 then, closed-loop control is 1A by the break-make of PWM modulator control metal-oxide-semiconductor thereby make outputting current steadily.
2. filtering circuit
Filtering circuit can effectively suppress electric network noise, improves Electro Magnetic Compatibility and the reliability of tester, selects the second order common-mode filter here for use, here main filtering switching noise and the harmonic wave that caused by input line.When common mode interference occurring in the circuit, because the flow direction unanimity of two coils among the L, the total inductance amount increases rapidly after the fine overcoupling, thereby common-mode signal is produced very big induction reactance, make it to be difficult for passing through, these two coils are respectively on the ferrite bead of low-loss, high permeability.Directly grounded two capacitor C 1, C2 are mainly used to the filtering series mode interference.It is surge suppressor that L1, D1 and D2 form excess voltage suppressor jointly, prevents from surpassing their specified momentary outputs and passes through, the protection subsequent conditioning circuit.By behind the rectifier again by DC filtering with filtering spiking etc.
3. reference voltage (Vref) circuit
Stable in order to improve the output of modulus conversion chip precision and constant-current source circuit, the multiple factors such as temperature, drift that reduce are to the influence of equipment precision, utilize accurate voltage chip LM399 to set up high-precision voltage reference, and further making reference voltage keep stable by amplifier LM258, physical circuit is as shown in Figure 3.
4. data acquisition and treatment circuit
The data acquisition of tester and treatment circuit are as shown in Figure 4, voltage signal keeps chip and AD sampling A finally to deliver in the single-chip microcomputer by special sampling, single-chip microcomputer carries out analyzing and processing to the waveform of being made up of transition resistance, transition current (as shown in Figure 5), finally directly be presented on the display screen, simultaneously also printable and communicate by the RS232 interface.
Sampling keeps chip to adopt LF298, and its feature is to be made of field effect transistor, has the sample rate height, keeps the voltage characteristics such as slow and precision height that descend.When as single amplifier, its DC current gain precision is 0.002%, the sampling time during less than 6 μ s precision can reach 0.01%; The adjustment of input offset voltage only needs to get final product in the offset side adjustment, and under the situation that does not reduce bias current, bandwidth allows 1MHz, can guarantee the same period and the accuracy requirement of three phase samplers so fully.
The AD conversion chip adopts AD7714, and it is a complete AFE (analog front end) that is used for the low frequency measurement application scenario, is used for directly receiving small-signal and exporting the serial digital amount from circuit.It uses ∑-Δ switch technology to realize can not losing up to the code of 24 precision, and 3 difference analogue inputs and a difference benchmark input are arranged, and is used for connecing reference signal.
Technical indicator is as follows:
1, three-phase constant-current output is 1A
2, the measurement of transit time: 0-250ms, 0.1 grade of precision
3, the measurement of transition resistance: (0.1-40) Ω, 0.1 grade of precision
4, three-phase synchronism: 0.1 grade of precision
Claims (1)
1. transformer on-load tap changer tester, it is characterized in that: its circuit module structure is: adopt filtering circuit respectively with constant-current source circuit, reference voltage circuit connects, reference voltage circuit is connected with constant-current source circuit again, constant-current source circuit is connected with treatment circuit with data acquisition again, H bridge and high-frequency transformer that constant-current source circuit is made up of field effect transistor are formed, filtering circuit is suppressed by ac filter and superpotential, DC filtering is formed, wherein ac filter partly contains two coils on the ferrite, reference voltage circuit is made up of voltage chip LM399 and amplifier LM258, amplifier LM258 is divided into two-stage and amplifies, DC voltage+12V is carried in DC voltage port 3 ports of voltage chip LM399 and cathode voltage port 8 ports of amplifier LM258 first order amplifying unit respectively, DC voltage+12V is again by resistance R 118, resistance R 81, resistance R 93 is connected to input port 3 ports of amplifier LM258 first order amplifying unit, DC voltage+12V is connected to the anodal port one port of input of voltage chip LM399 by resistance R 118, the input negative pole port 2 port ground connection of voltage chip LM399, DC voltage-12V is carried in DC voltage port 4 ports of voltage chip LM399 and cathode voltage port 4 ports of amplifier LM258 first order amplifying unit respectively, the sampling reference voltage AD-VREF that the amplifier LM258 first order is amplified back output connects data acquisition and treatment circuit, the current feedback circuit of the reference voltage Vref connection constant-current source circuit of back output is amplified in the amplifier LM258 second level, and data acquisition and treatment circuit comprise that sampling keeps chip LF298 and AD analog to digital conversion AD7714; Current feedback circuit comprises: after the output current feedback is subtracted each other with reference voltage Vref, will subtract back input current ring corrective network as a result, thereby control PWM modulator constitutes current feedback circuit; Constant-current source circuit partly is output as the DC current of 1A.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010584656 CN102129032B (en) | 2010-12-13 | 2010-12-13 | Transformer on-load tapping switch tester |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010584656 CN102129032B (en) | 2010-12-13 | 2010-12-13 | Transformer on-load tapping switch tester |
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| CN102129032A CN102129032A (en) | 2011-07-20 |
| CN102129032B true CN102129032B (en) | 2013-08-21 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103323671B (en) * | 2013-06-14 | 2015-08-05 | 国家电网公司 | Transformer directly hinders and loaded switch parameter measuring apparatus |
| CN108344941A (en) * | 2018-01-10 | 2018-07-31 | 中国电力科学研究院有限公司 | A kind of system and method for the hybrid load ratio bridging switch thyristor module performance of test |
| CN109001608A (en) * | 2018-06-26 | 2018-12-14 | 中国电力科学研究院有限公司 | A kind of simulation test device of hybrid load ratio bridging switch thyristor module |
| CN110646018B (en) * | 2019-09-12 | 2021-10-19 | 东南大学 | High-frequency current source Wheatstone bridge detection circuit realized by low-speed operational amplifier |
| CN111624457B (en) * | 2020-05-08 | 2022-10-04 | 南方电网科学研究院有限责任公司 | Simulation test method for thyristor module action characteristics |
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| JPH10285923A (en) * | 1997-03-31 | 1998-10-23 | Canon Inc | Power unit and method for controlling its voltage |
| JP2005039975A (en) * | 2003-07-18 | 2005-02-10 | Sony Corp | Current resonant converter |
| CN2696015Y (en) * | 2004-04-16 | 2005-04-27 | 中国科学院近代物理研究所 | Extreme high precision reference voltage source |
| CN101350557B (en) * | 2007-07-18 | 2011-04-27 | 华为技术有限公司 | Apparatus for adjusting power supply |
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