CN220289829U - Eight-channel residual current transformer broken wire and short wire detection circuit - Google Patents
Eight-channel residual current transformer broken wire and short wire detection circuit Download PDFInfo
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- CN220289829U CN220289829U CN202320668704.0U CN202320668704U CN220289829U CN 220289829 U CN220289829 U CN 220289829U CN 202320668704 U CN202320668704 U CN 202320668704U CN 220289829 U CN220289829 U CN 220289829U
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- 238000001514 detection method Methods 0.000 title claims abstract description 45
- 230000001052 transient effect Effects 0.000 claims description 11
- 239000003990 capacitor Substances 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000002457 bidirectional effect Effects 0.000 description 8
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- 230000009286 beneficial effect Effects 0.000 description 1
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Abstract
The utility model discloses an eight-channel residual current transformer broken wire and short wire detection circuit, which comprises: the signal acquisition circuit comprises a residual current transformer CT_1, a secondary signal load resistor R47, an RC filter and an N-channel MOS tube Q1, wherein the first end of the residual current transformer CT_1 is connected with the first end of the secondary signal load resistor R47, the second end of the residual current transformer CT_1 is connected with the second end of the secondary signal load resistor R47, the first end of the secondary signal load resistor R47 is connected with an analog ground AGND, the second end of the secondary signal load resistor R47 is connected with the RC filter and the source electrode of the N-channel MOS tube Q1, and the secondary signal load resistor R47 is used for converting a secondary current signal of the residual current transformer into a voltage signal. The problems of broken wire and short wire detection of the multi-channel residual current transformer are solved by the combined application of the three-eight decoder and the data check device, and the multi-channel residual current transformer has higher economic value.
Description
Technical Field
The utility model relates to the technical field of alternating current systems, in particular to an eight-channel residual current transformer disconnection and short-circuit detection circuit.
Background
Along with the increasing importance of power plants and substations to alternating current systems, the fire fighting capability lifting requirements of the substations are also becoming more and more urgent, and as more alternating current power supply main feeder lines for the substations are provided, more than ten alternating current feeder lines are usually arranged in an alternating current feeder line screen on one side to be detected, so that the residual current monitoring device of the alternating current feeder lines for the substations is usually required to collect the residual currents of a plurality of alternating current feeder lines simultaneously. Because the acquisition channels are more, in order to avoid that the switching time of a plurality of channels is long, the detection of broken lines and short lines influences the current value actually acquired, a circuit scheme capable of rapidly switching the channels needs to be selected, and the function of channel isolation is realized.
Disclosure of Invention
The utility model mainly aims to provide an eight-channel residual current transformer wire breakage and short wire detection circuit which can effectively solve the problems in the background technology.
In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:
the utility model provides a surplus current transformer broken string and stub detection circuit of eight passageways which characterized in that includes:
the signal acquisition circuit comprises a residual current transformer CT_1, a secondary signal load resistor R47, an RC filter and an N-channel MOS tube Q1, wherein the first end of the residual current transformer CT_1 is connected with the first end of the secondary signal load resistor R47, the second end of the residual current transformer CT_1 is connected with the second end of the secondary signal load resistor R47, the first end of the secondary signal load resistor R47 is connected with an analog ground AGND, the second end of the secondary signal load resistor R47 is connected with the RC filter and the source electrode of the N-channel MOS tube Q1, and the secondary signal load resistor R47 is used for converting a secondary current signal of the residual current transformer into a voltage signal.
The problems of broken wire and short wire detection of the multi-channel residual current transformer are solved through the combined application of the three-eight decoder and the data check device, and the chip device is mature, low in cost and high in economic value;
the circuit scheme can be expanded, the eight-channel acquisition switching chip is used, and the circuit can be expanded to sixteen, twenty-four and thirty-two channel broken line and short line detection by replacing a sixteen-channel decoder and a data check device or combining a plurality of eight-channel chips.
As a preferred embodiment, the signal acquisition circuit further includes a bidirectional transient diode D7, the bidirectional transient diode D7 is used for circuit protection, and a first end of the bidirectional transient diode D7 is connected to the first end of the residual current transformer ct_1 and the first end of the secondary signal load resistor R47.
As a preferred embodiment, the RC filter comprises a resistor R48 and a capacitor C38 connected in series, wherein a first end of the resistor R48 is connected to a second end of the secondary signal load resistor R47.
As a preferred implementation manner, the number of the signal acquisition circuits is 8, in the signal acquisition circuits, ct_1 is an external residual current transformer, and D7 is a bidirectional transient diode for circuit protection; r47 is a secondary signal load resistor for converting a secondary current signal of the residual current transformer into a voltage signal, and R48 and C38 are RC filters for converting the voltage signal; q1 is an N-channel MOS tube, DXKZ_01 is a control signal for controlling the conduction of the MOS tube, the level is 0 or 3.3V, rct is CT_1 internal resistance, the circuit is a signal acquisition circuit of one channel, and the other 2-8 channels all adopt the same circuit.
When the power is initially on, the DXKZ_01 control level is 0V, the Q1MOS tube is not conducted, and the In_V01 detection signal is the residual current value. When In_V01 is not 0, the current residual current transformer is considered to have no wire breakage and short wire condition, and the wire breakage and short wire detection function is not started; when In_V01 is 0, the current residual current transformer is considered to have the possibility of faults, disconnection and short-line detection are started, the DXKZ_01 control level is 3.3V, the MOS tube is conducted, R47 is connected with the internal resistance of the transformer In parallel, and a voltage dividing circuit is formed with R126. When In_V01 is 0, the secondary signal of the transformer is considered to form a short line; when in_v01 is VCC_5V (R47/R126), the secondary signal of the transformer is considered to form a broken line; when in_v01 is vcc_5v (R47/(R126// Rct)), the secondary signal wiring of the transformer is considered to be normal, and no disconnection or short-circuit condition exists.
As a preferred embodiment, further comprising a channel switching circuit, the channel switching circuit comprising:
a tri-eight decoder U32, wherein the tri-eight decoder U32 is configured to perform enable control by using a 238_en2 signal, start or close wire break and short wire detection, and select a channel to be detected by using 4051_a, 4051_b, and 4051_c;
a data check U22, wherein the data check U22 enables sampling channels through 4051_EN1 and selects channels to be sampled through 4051_A, 4051_B and 4051_C;
and an operational amplifier U34, wherein the operational amplifier U34 is used for following and filtering the acquisition signal.
When the power is initially turned on, the level of 238_EN2 is controlled to be 0V, the three-eight decoder is not enabled, the disconnection and short line detection are stopped, the level of the data check device 4051_EN1 is controlled to be 0V (low level enabled), the data acquisition function is started, in_V 01-V08 channels are selected through 4051_A, 4051_B and 4051_C, and the detection value of 4051_OUT is the residual current value of the corresponding channel.
When the in_v01-V08 channels have the value of 0, the level of 238_en2 is controlled to be 3.3V, the disconnection and disconnection detection are started, the channel needing detection is selected through 4051_a, 4051_b and 4051_c, meanwhile, the U22 data acquisition channel is started, the 4051_OUT detection value is the disconnection and disconnection detection value of the corresponding channel, and the secondary wiring state of the currently selected channel residual current transformer is determined through analysis of the detection voltage value.
Compared with the prior art, the utility model has the following beneficial effects:
the problems of broken wire and short wire detection of the multi-channel residual current transformer are solved through the combined application of the three-eight decoder and the data check device, and the chip device is mature, low in cost and high in economic value;
the circuit scheme can be expanded, the eight-channel acquisition switching chip is used, and the circuit can be expanded to sixteen, twenty-four and thirty-two channel broken line and short line detection by replacing a sixteen-channel decoder and a data check device or combining a plurality of eight-channel chips.
Drawings
In order to more clearly illustrate the embodiments of the utility model or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the utility model, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a schematic diagram of a signal acquisition circuit of an eight-channel residual current transformer wire break and short wire detection circuit according to the present utility model.
Fig. 2 is a schematic diagram of a channel switching circuit of an eight-channel residual current transformer disconnection and short-circuit detection circuit according to the present utility model.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
The eight-channel residual current transformer disconnection and short-circuit detection circuit as shown in fig. 1-2 is characterized by comprising:
the signal acquisition circuit comprises a residual current transformer CT_1, a secondary signal load resistor R47, an RC filter and an N-channel MOS tube Q1, wherein the first end of the residual current transformer CT_1 is connected with the first end of the secondary signal load resistor R47, the second end of the residual current transformer CT_1 is connected with the second end of the secondary signal load resistor R47, the first end of the secondary signal load resistor R47 is connected with an analog ground AGND, the second end of the secondary signal load resistor R47 is connected with the RC filter and the source electrode of the N-channel MOS tube Q1, and the secondary signal load resistor R47 is used for converting a secondary current signal of the residual current transformer into a voltage signal.
The problems of broken wire and short wire detection of the multi-channel residual current transformer are solved through the combined application of the three-eight decoder and the data check device, and the chip device is mature, low in cost and high in economic value;
the circuit scheme can be expanded, the eight-channel acquisition switching chip is used, and the circuit can be expanded to sixteen, twenty-four and thirty-two channel broken line and short line detection by replacing a sixteen-channel decoder and a data check device or combining a plurality of eight-channel chips.
The signal acquisition circuit further comprises a bidirectional transient diode D7, the bidirectional transient diode D7 is used for circuit protection, and a first end of the bidirectional transient diode D7 is connected with a first end of the residual current transformer CT_1 and a first end of the secondary signal load resistor R47.
The RC filter comprises a resistor R48 and a capacitor C38 which are connected in series, and a first end of the resistor R48 is connected with a second end of the secondary signal load resistor R47.
In the signal acquisition circuit, CT_1 is an external residual current transformer, and D7 is a bidirectional transient diode for circuit protection; r47 is a secondary signal load resistor for converting a secondary current signal of the residual current transformer into a voltage signal, and R48 and C38 are RC filters for converting the voltage signal; q1 is an N-channel MOS tube, DXKZ_01 is a control signal for controlling the conduction of the MOS tube, the level is 0 or 3.3V, rct is CT_1 internal resistance, the circuit is a signal acquisition circuit of one channel, and the other 2-8 channels all adopt the same circuit.
When the power is initially on, the DXKZ_01 control level is 0V, the Q1MOS tube is not conducted, and the In_V01 detection signal is the residual current value. When In_V01 is not 0, the current residual current transformer is considered to have no wire breakage and short wire condition, and the wire breakage and short wire detection function is not started; when In_V01 is 0, the current residual current transformer is considered to have the possibility of faults, disconnection and short-line detection are started, the DXKZ_01 control level is 3.3V, the MOS tube is conducted, R47 is connected with the internal resistance of the transformer In parallel, and a voltage dividing circuit is formed with R126. When In_V01 is 0, the secondary signal of the transformer is considered to form a short line; when in_v01 is VCC_5V (R47/R126), the secondary signal of the transformer is considered to form a broken line; when in_v01 is vcc_5v (R47/(R126// Rct)), the secondary signal wiring of the transformer is considered to be normal, and no disconnection or short-circuit condition exists.
Wherein, still include the passageway switching circuit, the passageway switching circuit includes:
a tri-eight decoder U32, wherein the tri-eight decoder U32 is configured to perform enable control by using a 238_en2 signal, start or close wire break and short wire detection, and select a channel to be detected by using 4051_a, 4051_b, and 4051_c;
a data check U22, wherein the data check U22 enables sampling channels through 4051_EN1 and selects channels to be sampled through 4051_A, 4051_B and 4051_C;
and an operational amplifier U34, wherein the operational amplifier U34 is used for following and filtering the acquisition signal.
When the power is initially turned on, the level of 238_EN2 is controlled to be 0V, the three-eight decoder is not enabled, the disconnection and short line detection are stopped, the level of the data check device 4051_EN1 is controlled to be 0V (low level enabled), the data acquisition function is started, in_V 01-V08 channels are selected through 4051_A, 4051_B and 4051_C, and the detection value of 4051_OUT is the residual current value of the corresponding channel.
When the in_v01-V08 channels have the value of 0, the level of 238_en2 is controlled to be 3.3V, the disconnection and disconnection detection are started, the channel needing detection is selected through 4051_a, 4051_b and 4051_c, meanwhile, the U22 data acquisition channel is started, the 4051_OUT detection value is the disconnection and disconnection detection value of the corresponding channel, and the secondary wiring state of the currently selected channel residual current transformer is determined through analysis of the detection voltage value.
In the description of the present utility model, it should be understood that the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model. In the description of the present utility model, unless otherwise specified and defined, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, mechanical or electrical, or may be in communication with each other between two elements, directly or indirectly through intermediaries, as would be understood by those skilled in the art, in view of the specific meaning of the terms described above.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.
Claims (5)
1. The utility model provides a surplus current transformer broken string and stub detection circuit of eight passageways which characterized in that includes:
the signal acquisition circuit comprises a residual current transformer CT_1, a secondary signal load resistor R47, an RC filter and an N-channel MOS tube Q1, wherein the first end of the residual current transformer CT_1 is connected with the first end of the secondary signal load resistor R47, the second end of the residual current transformer CT_1 is connected with the second end of the secondary signal load resistor R47, the first end of the secondary signal load resistor R47 is connected with an analog ground AGND, the second end of the secondary signal load resistor R47 is connected with the RC filter and the source electrode of the N-channel MOS tube Q1, and the secondary signal load resistor R47 is used for converting a secondary current signal of the residual current transformer into a voltage signal.
2. The eight channel residual current transformer wire break and short circuit detection circuit according to claim 1, wherein the signal acquisition circuit further comprises a bi-directional transient diode D7, the bi-directional transient diode D7 is used for circuit protection, and a first end of the bi-directional transient diode D7 is connected with a first end of the residual current transformer ct_1 and a first end of the secondary signal load resistor R47.
3. The eight channel residual current transformer wire break and short detection circuit according to claim 1, wherein the RC filter comprises a resistor R48 and a capacitor C38 connected in series, a first end of the resistor R48 being connected to a second end of the secondary signal load resistor R47.
4. The eight-channel residual current transformer wire break and short wire detection circuit according to claim 1, wherein the number of the signal acquisition circuits is 8.
5. The eight channel residual current transformer wire break and stub detection circuit of claim 1, further comprising a channel switching circuit comprising:
a tri-eight decoder U32, wherein the tri-eight decoder U32 is configured to perform enable control by using a 238_en2 signal, start or close wire break and short wire detection, and select a channel to be detected by using 4051_a, 4051_b, and 4051_c;
a data check U22, wherein the data check U22 enables sampling channels through 4051_EN1 and selects channels to be sampled through 4051_A, 4051_B and 4051_C;
and an operational amplifier U34, wherein the operational amplifier U34 is used for following and filtering the acquisition signal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202320668704.0U CN220289829U (en) | 2023-03-30 | 2023-03-30 | Eight-channel residual current transformer broken wire and short wire detection circuit |
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| CN202320668704.0U CN220289829U (en) | 2023-03-30 | 2023-03-30 | Eight-channel residual current transformer broken wire and short wire detection circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118131110A (en) * | 2024-05-06 | 2024-06-04 | 云南电网有限责任公司 | Voltage transformer error characteristic simulation test platform and test method thereof |
| CN119251961A (en) * | 2024-12-04 | 2025-01-03 | 深圳欧米智能科技有限公司 | Method and system for monitoring anti-shearing alarm of steel cable |
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2023
- 2023-03-30 CN CN202320668704.0U patent/CN220289829U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118131110A (en) * | 2024-05-06 | 2024-06-04 | 云南电网有限责任公司 | Voltage transformer error characteristic simulation test platform and test method thereof |
| CN119251961A (en) * | 2024-12-04 | 2025-01-03 | 深圳欧米智能科技有限公司 | Method and system for monitoring anti-shearing alarm of steel cable |
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