CN108761191B - Traveling wave protection acquisition circuit - Google Patents
Traveling wave protection acquisition circuit Download PDFInfo
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- CN108761191B CN108761191B CN201810980762.0A CN201810980762A CN108761191B CN 108761191 B CN108761191 B CN 108761191B CN 201810980762 A CN201810980762 A CN 201810980762A CN 108761191 B CN108761191 B CN 108761191B
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- 239000003990 capacitor Substances 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 12
- 230000005404 monopole Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 abstract description 8
- 238000010586 diagram Methods 0.000 description 6
- 230000006978 adaptation Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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Abstract
The invention discloses a traveling wave protection acquisition circuit, which comprises a current transformer, a precise operational amplifier follower circuit, a precise operational amplifier reverse proportion attenuator circuit, a bipolar single-ended to single-polarity differential circuit and a single-channel single-pole differential high-precision AD acquisition circuit, and is characterized in that: the output end of the current transformer is connected with the positive input end of the precise operational amplifier follower circuit, the output end of the precise operational amplifier follower circuit is connected with the input end of the bipolar single-ended to single-polarity differential circuit, the output end of the bipolar single-ended to single-polarity differential circuit is connected with the input end of the single-channel single-pole differential high-precision AD acquisition circuit, the output end of the precise operational amplifier reverse proportion attenuator circuit is connected with the bipolar single-ended to single-polarity differential circuit, the driving load capacity is strong, the sampling precision is high, the sampling rate is fast, and the current transformer is suitable for traveling wave protection acquisition and has higher practical value and wide application prospect.
Description
Technical Field
The invention relates to the technical field of circuit design, in particular to a traveling wave protection acquisition circuit design method.
Background
A high-voltage long-distance transmission line in a power system belongs to a distributed parameter circuit, and electromagnetic energy generated during state switching or disturbance of the power system can induce a wave process in the high-voltage long-distance transmission line. Traveling waves are transient components that propagate at approximately the speed of light, even on a 1000km long line, for a time of no more than 5ms. The prior art protection devices are not capable of accurately capturing and analyzing such signals and are not useful in production practice.
The scholars at home and abroad begin to study protection and ranging based on traveling waves in 1950 s, and the difficulties are concentrated on: the travelling wave exists only in a very short time window, so that the travelling wave is difficult to serve as a main protection; an acquisition circuit is built by using an operational amplifier earlier, and although the problem of insufficient acquisition density does not exist, the problem of cache and alignment is encountered during differential signal extraction; before large-area popularization of GPS/Beidou, a wide-area time synchronization means is lacking. In addition, the debugging running instrument of the device is special, so that the popularization of traveling wave protection is limited.
In recent years, engineering practice of using the traveling wave principle for fault location has been gradually developed, but the design of a traveling wave acquisition circuit is still immature, and how to realize high-precision and high-sampling acquisition of traveling wave signals becomes a problem to be solved.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a traveling wave protection acquisition circuit, which solves the technical problems that the signal cannot be accurately captured and analyzed and cannot be used for production practice due to the arrangement of a current transformer, a precise operational amplifier follower circuit, a precise operational amplifier reverse proportion attenuator circuit, a bipolar single-ended to single-polarity differential circuit and single-channel single-polarity differential high-precision AD acquisition.
In order to achieve the above purpose, the invention adopts the following technical scheme: the traveling wave protection acquisition circuit comprises a current transformer, a precise operational amplifier follower circuit, a precise operational amplifier reverse proportion attenuator circuit, a bipolar single-ended to single-polarity differential circuit and a single-channel single-pole differential high-precision AD acquisition circuit, wherein the output end of the current transformer is connected with the positive input end of the precise operational amplifier follower circuit, the output end of the precise operational amplifier follower circuit is connected with the input end of the bipolar single-ended to single-polarity differential circuit, the output end of the bipolar single-ended to single-polarity differential circuit is connected with the input end of the single-channel single-pole differential high-precision AD acquisition circuit, and the output end of the precise operational amplifier reverse proportion attenuator circuit is connected with the bipolar single-ended to single-polarity differential circuit.
Preferably, the output end of the current transformer is connected with a first resistor R1, and the first resistor R1 is connected with the precise operational amplifier follower circuit.
Preferably, the output end of the precise operational amplifier I is connected with the second resistor R2, and the reverse input end of the precise operational amplifier I is connected with the output end of the precise operational amplifier.
Preferably, the precise operational amplifier reverse proportion attenuator circuit comprises a precise operational amplifier II, a third resistor R3, a fourth resistor R4 and a fifth resistor R5, wherein the non-inverting input end of the precise operational amplifier II is grounded through the fifth resistor R5, the inverting input end of the precise operational amplifier II is connected to the positive voltage end through the third resistor R3, the inverting input end of the precise operational amplifier II is connected to the output end of the precise operational amplifier II through the fourth resistor R4, and the output end of the precise operational amplifier II is connected to the bipolar single-ended-to-single-polarity differential circuit.
Preferably, the bipolar single-ended to unipolar differential circuit includes a fully differential attenuation amplifier and a low-pass filter circuit, a sixth resistor R6, a seventh resistor R7, a first capacitor C1, a second capacitor C2, and a third capacitor C3, where a bias voltage VOCM end of the fully differential attenuation amplifier is connected to an output end of the precision operational amplifier, a non-inverting input end of the fully differential attenuation amplifier is connected to an output end of the second resistor R2 of the precision operational amplifier follower circuit, an inverting input end of the fully differential attenuation amplifier is grounded, a negative output end of the fully differential attenuation amplifier is connected to the single-channel unipolar differential high-precision AD acquisition circuit through the sixth resistor R6, a positive output end of the fully differential attenuation amplifier is connected to the single-channel unipolar differential high-precision AD acquisition circuit through the seventh resistor R7, the first capacitor C1 and the second capacitor C2 are connected in series and then connected between an output end of the sixth resistor R6 and an output end of the seventh resistor R7, and the third capacitor C3 is simultaneously connected between an output end of the sixth resistor R6 and an output end of the seventh resistor R7.
Preferably, the proportional relationship between the third resistor R3 and the fourth resistor R4 is that the fourth resistor R4/the third resistor r3=the bias voltage VOCOM/the voltage VCC.
Preferably, the single-channel monopole differential high-precision AD acquisition circuit comprises a high-precision AD conversion circuit, wherein the negative input end of the high-precision AD conversion circuit is connected to the output end of a seventh resistor R7, the positive input end of the high-precision AD conversion circuit is connected to the output end of a sixth resistor R6, and the digital circuit signal of the high-precision AD conversion circuit is connected with the SPI interface of the MPC8247 processor through an SCK pin, an SDO pin, a CNV pin and an SDI pin.
Compared with the prior art, the invention has the beneficial effects that: the invention discloses a traveling wave protection acquisition circuit, which comprises a current transformer, a follower circuit built by a precise operational amplifier, a reverse proportional attenuator circuit built by the precise operational amplifier, a bias voltage providing circuit for converting a bipolar single-ended signal into a unipolar differential signal, a single-channel single-pole differential high-precision AD acquisition circuit for sampling a single-channel secondary voltage, and the follower circuit is strong in driving load capacity, high in sampling precision and fast in sampling rate, is suitable for traveling wave protection acquisition, and has higher practical value and wide application prospect.
Drawings
FIG. 1 is a schematic diagram of a current transformer of a traveling wave protection acquisition circuit of the present invention;
FIG. 2 is a schematic diagram of a follower circuit built by a precision operational amplifier of the traveling wave protection acquisition circuit;
FIG. 3 is a schematic diagram of a reverse proportional attenuator circuit constructed by a precision operational amplifier of the traveling wave protection acquisition circuit;
FIG. 4 is a schematic diagram of a fully differential attenuation amplifier of a traveling wave protection acquisition circuit and a bipolar single-ended to single-polarity differential circuit built by a low-pass filter circuit of the present invention;
fig. 5 is a schematic diagram of a single-channel monopole differential high-precision AD acquisition circuit of a traveling wave protection acquisition circuit of the present invention;
fig. 6 is an overall circuit schematic diagram of a traveling wave protection acquisition circuit of the present invention.
Detailed Description
The invention will be further described with reference to specific examples.
As shown in fig. 1-6, a traveling wave protection acquisition circuit comprises a current transformer, a precise operational amplifier follower circuit, a precise operational amplifier reverse proportion attenuator circuit, a bipolar single-ended to single-polarity differential circuit and a single-channel single-polarity differential high-precision AD acquisition circuit, wherein the output end of the current transformer is connected with the positive input end of the precise operational amplifier follower circuit, the output end of the precise operational amplifier follower circuit is connected with the input end of the bipolar single-ended to single-polarity differential circuit, the output end of the bipolar single-ended to single-polarity differential circuit is connected with the input end of the single-channel single-polarity differential high-precision AD acquisition circuit, and the output end of the precise operational amplifier reverse proportion attenuator circuit is connected with the bipolar single-ended to single-polarity differential circuit.
In this embodiment, the output end of the current transformer is connected with a first resistor R1, and the first resistor R1 is connected with the precision operational amplifier follower circuit, and is used for converting primary large current of electric power into secondary small voltage.
In this embodiment, the output end of the first precise operational amplifier is connected to the second resistor R2, the reverse input end of the first precise operational amplifier is connected to the output end of the precise operational amplifier, and it is noted that the resistance of the first resistance R1 is the same as the resistance of the second resistance R2, so as to form a follower circuit for enhancing the capability of the signal source to drive the load.
In this embodiment, the precise operational amplifier reverse proportion attenuator circuit includes a precise operational amplifier second, a third resistor R3, a fourth resistor R4, and a fifth resistor R5, where the in-phase input end of the precise operational amplifier second is grounded through the fifth resistor R5, the precise operational amplifier second inverting input end is connected to the positive voltage end through the third resistor R3, the precise operational amplifier second inverting input end is connected to the output end of the precise operational amplifier second through the fourth resistor R4, and the output end of the precise operational amplifier second is connected to the bipolar single-ended to single-polarity differential circuit, and is used for providing the bias voltage of the bipolar single-ended to single-polarity differential circuit.
In this embodiment, the bipolar single-ended to unipolar differential circuit includes a fully differential attenuation amplifier and a low-pass filter circuit, a sixth resistor R6, a seventh resistor R7, a first capacitor C1, a second capacitor C2, and a third capacitor C3, where a bias voltage VOCM end of the fully differential attenuation amplifier is connected to an output end of the precision operational amplifier, a non-inverting input end of the fully differential attenuation amplifier is connected to an output end of the second resistor R2 of the precision operational amplifier follower circuit, an inverting input end of the fully differential attenuation amplifier is grounded, a negative output end of the fully differential attenuation amplifier is connected to the single-channel unipolar differential high-precision AD acquisition circuit through the sixth resistor R6, a positive output end of the fully differential attenuation amplifier is connected to the single-channel unipolar differential high-precision AD acquisition circuit through the seventh resistor R7, the first capacitor C1 and the second capacitor C2 are connected in series between an output end of the sixth resistor R6 and an output end of the seventh resistor R7, and the third capacitor C3 is simultaneously connected between an output end of the sixth resistor R6 and an output end of the seventh resistor R7, and is used for converting a single-ended differential signal into a single-ended signal.
In this embodiment, the proportional relationship between the third resistor R3 and the fourth resistor R4 is that the fourth resistor R4/the third resistor r3=the bias voltage VOCOM/the voltage VCC.
In this embodiment, the single-channel unipolar differential high-precision AD acquisition circuit includes a high-precision AD conversion circuit, a negative input end of the high-precision AD conversion circuit is connected to an output end of the seventh resistor R7, a positive input end of the high-precision AD conversion circuit is connected to an output end of the sixth resistor R6, and a digital circuit signal of the high-precision AD conversion circuit is connected to an SPI interface of the MPC8247 processor through an SCK pin, an SDO pin, a CNV pin, and an SDI pin. The single-channel secondary voltage sampling device is used for sampling the single-channel secondary voltage and transmitting the obtained digital signal to the processor.
The foregoing is only a preferred embodiment of the invention, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.
Claims (5)
1. The utility model provides a travelling wave protection acquisition circuit, includes current transformer, accurate operational amplifier follower circuit, accurate operational amplifier reverse proportion attenuator circuit, bipolar single-ended to unipolar difference circuit, single-channel unipolar difference high accuracy AD acquisition circuit, its characterized in that: the output end of the current transformer is connected with the positive input end of the precise operational amplifier follower circuit, the output end of the precise operational amplifier follower circuit is connected with the input end of the bipolar single-ended to single-polarity differential circuit, the output end of the bipolar single-ended to single-polarity differential circuit is connected with the input end of the single-channel single-pole differential high-precision AD acquisition circuit, and the output end of the precise operational amplifier reverse proportion attenuator circuit is connected with the bipolar single-ended to single-polarity differential circuit;
the precise operational amplifier reverse proportion attenuator circuit comprises a precise operational amplifier II, a third resistor R3, a fourth resistor R4 and a fifth resistor R5, wherein the non-inverting input end of the precise operational amplifier II is grounded through the fifth resistor R5, the inverting input end of the precise operational amplifier II is connected to a positive voltage end through the third resistor R3, the inverting input end of the precise operational amplifier II is connected to the output end of the precise operational amplifier II through the fourth resistor R4, and the output end of the precise operational amplifier II is connected to a bipolar single-ended-to-single-polarity differential circuit;
the bipolar single-ended to unipolar differential circuit comprises a fully differential attenuation amplifier, a low-pass filter circuit, a sixth resistor R6, a seventh resistor R7, a first capacitor C1, a second capacitor C2 and a third capacitor C3, wherein the offset voltage VOCM end of the fully differential attenuation amplifier is connected with the output end of a second precise operational amplifier, the non-inverting input end of the fully differential attenuation amplifier is connected with the output end of a second resistor R2 of the precise operational amplifier follower circuit, the inverting input end of the fully differential attenuation amplifier is grounded, the negative output end of the fully differential attenuation amplifier is connected to the single-channel single-pole differential high-precision AD acquisition circuit through the sixth resistor R6, the positive output end of the fully differential attenuation amplifier is connected to the single-channel single-pole differential high-precision AD acquisition circuit through the seventh resistor R7, the first capacitor C1 is connected between the output end of the sixth resistor R6 and the output end of the seventh resistor R7 after being connected in series with the second capacitor C2, and the third capacitor C3 is simultaneously connected between the output end of the sixth resistor R6 and the output end of the seventh resistor R7.
2. The traveling wave protection acquisition circuit of claim 1, wherein: the output end of the current transformer is connected with a first resistor R1, and the first resistor R1 is connected with the precise operational amplifier follower circuit.
3. A traveling wave protection acquisition circuit according to claim 1 or 2, characterized in that: the precise operational amplifier follower circuit comprises a precise operational amplifier I and a second resistor R2, wherein the output end of the precise operational amplifier I is connected to a bipolar single-ended-to-single-polarity differential circuit through the second resistor R2, and the reverse input end of the precise operational amplifier I is connected with the output end of the precise operational amplifier.
4. The traveling wave protection acquisition circuit of claim 1, wherein: the proportional relationship between the third resistor R3 and the fourth resistor R4 is that the fourth resistor R4/the third resistor r3=the bias voltage VOCOM/the voltage VCC.
5. The traveling wave protection acquisition circuit of claim 2, wherein: the single-channel monopole differential high-precision AD acquisition circuit comprises a high-precision AD conversion circuit, wherein the negative input end of the high-precision AD conversion circuit is connected to the output end of a seventh resistor R7, the positive input end of the high-precision AD conversion circuit is connected to the output end of a sixth resistor R6, and the digital circuit signal of the high-precision AD conversion circuit is connected with the SPI interface of the MPC8247 processor through an SCK pin, an SDO pin, a CNV pin and an SDI pin.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810980762.0A CN108761191B (en) | 2018-08-27 | 2018-08-27 | Traveling wave protection acquisition circuit |
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| CN201810980762.0A CN108761191B (en) | 2018-08-27 | 2018-08-27 | Traveling wave protection acquisition circuit |
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| CN108761191B true CN108761191B (en) | 2023-12-19 |
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| CN109459600B (en) * | 2018-12-25 | 2024-04-30 | 北京华峰测控技术股份有限公司 | Floating wide-range voltage measurement circuit |
| CN111812159A (en) * | 2020-06-19 | 2020-10-23 | 福建氢启健康科技有限公司 | Water quality detection circuit and method for water storage tank of oxyhydrogen breathing machine |
| CN115347680B (en) * | 2022-10-18 | 2023-02-03 | 国网湖北省电力有限公司电力科学研究院 | Remote power failure monitoring system and method based on time sensitive network |
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