CN205539135U - High reliability high accuracy current measuring device - Google Patents
High reliability high accuracy current measuring device Download PDFInfo
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- CN205539135U CN205539135U CN201620058160.6U CN201620058160U CN205539135U CN 205539135 U CN205539135 U CN 205539135U CN 201620058160 U CN201620058160 U CN 201620058160U CN 205539135 U CN205539135 U CN 205539135U
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- 230000004224 protection Effects 0.000 claims abstract description 15
- 238000004080 punching Methods 0.000 claims abstract description 14
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 20
- 229910052697 platinum Inorganic materials 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000013519 translation Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 abstract description 16
- 238000000034 method Methods 0.000 abstract description 4
- 230000007774 longterm Effects 0.000 abstract description 2
- 238000012544 monitoring process Methods 0.000 abstract description 2
- 230000000007 visual effect Effects 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 239000012634 fragment Substances 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000002730 additional effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The utility model provides a high reliability high accuracy current measuring device belongs to electrical measurement technical field, and the current measurement sensor is zero magnetic flow current transformer, adopts not opening punching connected mode access current loop, does not have the magnetic leakage, and current loop electrical connecting point is directly perceived visual, does not have the risk of opening a way. The device has multistage protection function and a screened circuit, and the protection sensor, the circuit can not be because of opening a way the damage under the extreme condition, and the current measurement scope is simply adjustable, and its precision receives influence of temperature hardly, reaches 0.02 grade level. The utility model discloses the method can conveniently insert the on -the -spot secondary current return circuit of transformer substation, and long -term suspended net carries out electric current on line measurement, has improved the on -line monitoring level.
Description
Technical field
This utility model relates to Electric Measurement Technology field, is specifically related to reliability high-precision current measuring device.
Background technology
In transformer station's online monitoring system, need the parameters such as the secondary loop current of equipment, Leakage Current in transformer station are carried out real-time on-line measurement, owing to current measurement needs long-term hanging net operation, the reliability and precision measuring access is had the highest requirement.Existing mode typically uses the mode of directly series connection to access, and junction point is positioned at inside device, it is impossible to intuitive judgment loop state, and the maintenance of measurement apparatus has influence on the connection of secondary circuit.
Utility model content
Technical problem to be solved in the utility model is for problem present in above-mentioned background technology, a kind of reliability high-precision current measuring device is provided, can be under substation field ensures the precondition of reliability, realize the high-acruracy survey of loop current, facilitate repair and maintenance and measure test.
For solving above-mentioned technical problem, the technical solution adopted in the utility model is: a kind of reliability high-precision current measuring device, including zero-flux current transformer, it is characterized in that, zero-flux current transformer uses not opening punching connected mode to access current loop, zero-flux current transformer is wrapped up by metal shielding, metal shielding connects shielded cable, zero-flux current transformer connects change-over circuit by shielded cable and shielded cable joint, described shielded cable joint is between shielded cable and switching current, and shielded cable joint is integrated with normally closed travel switch.Opening does not refers to that the magnetic material of transformer is that Guan Bi is looped.
Described change-over circuit uses amplifier to build I/V translation circuit, and Current Transformer Secondary side electric current flows through amplifier outfan through platinum resistance, and the input of amplifier is by two 1N4148 diode clamp protection amplifiers.
When shielded cable joint disconnects with change-over circuit, automatic short circuit current transformer secondary side circuit, described change-over circuit is connected with shielded cable joint by connecting seat.
Reliability high-precision current measuring method, comprises the following steps:
Zero-flux current transformer, metal shielding, shielded cable, shielded cable joint and connection seat are installed on outside device, amplifier is arranged at inside device, current loop uses not opening punching connected mode to pass zero-flux current transformer, the number of turn adjustable of punching；Use shielded cable to connect shielding case and zero-flux current transformer secondary side circuit is carried out shielding protection；The built-in normally closed travel switch of shielded cable joint；When shielded cable joint be connected seat disconnect time, the Guan Bi of travel switch ensures that Current Transformer Secondary side loop is not opened a way, when shielded cable joint connects upper connecting base, in connecting seat, contact pushes down normally closed travel switch shell fragment, and Current Transformer Secondary side loop is linked change-over circuit；Described change-over circuit is amplifier positive and negative terminal, and Current Transformer Secondary side electric current flows through amplifier outfan through platinum resistance, uses platinum resistance to realize I/V conversion.Device refers to the equipment that voltage x current data are acquired conversion, refers to the inside of this equipment inside device；Change-over circuit is linked on the interface (interface is connected with shielded cable joint) of this device, the cable connected outside device interface is the shielded cable with screen layer, connecting seat to be arranged on the shell of device, change-over circuit is connected to zero-flux current transformer current loop by interface, shielded cable joint, shielded cable.
Change the number of turn of zero-flux current transformer punching, and the multiplying power of device internal amplifier I/V conversion is to change measurement scope.
The input of amplifier when stream crossed by current transformer or device does not power on, will not damage amplifier by two 1N4148 diode clamp protections.
The I/V translation circuit of amplifier and shielded cable effectively inhibit common mode disturbances, the precision of I/V conversion to depend on current transformer precision and platinum resistance precision.
Compared with prior art, this utility model has the advantages that
Under conditions of this utility model can connect not changing on-the-spot secondary circuit, it is achieved measurement high-precision to loop current, and device possesses multi-stage protection function, it is ensured that sensor, circuit are not affected by open circuit, power-off.
Accompanying drawing explanation
Fig. 1 is reliability high-precision current measuring device structure chart of the present utility model；
Wherein 1 zero-flux current transformer, 2 current loops, 3 shielding cases, 4 shielded cables, 5 normally closed travel switches, 6 joints, 7 connect seat, inside 8 measurement apparatus, 9 diodes, 10 platinum resistance.
Detailed description of the invention
Below in conjunction with the accompanying drawings this utility model is further described.
(1) current loop 2 uses not opening punching connected mode to pass zero-flux current transformer 1, and the number of turn of punching is variable.Current transformer punching one circle no-load voltage ratio is 1000:1, and two circles are 2000:1, by that analogy.If measuring electric current to be 6A to the maximum, then can design punching two circle, Current Transformer Secondary side electric current is 12mA to the maximum, and peak-to-peak value is 17mA.Opening does not refers to that the magnetic material referring to transformer is that Guan Bi is looped, it is impossible to open.
(2) Current Transformer Secondary side electric current is less, and when primary side current is 250mA, secondary side current is 125uA, uses shielded cable 4 to connect shielding case 3 and secondary side current loop is carried out shielding protection.
(3) the built-in normally closed travel switch 5 of the joint 6 of shielded cable, when be connected seat 7 disconnect time, travel switch closes, ensure that Current Transformer Secondary side current loop is not opened a way, when connecing upper connecting base, connect contact in seat to push down normally closed travel switch shell fragment and make normally closed travel switch disconnect, Current Transformer Secondary side loop is linked amplifier positive and negative terminal.Secondary side circuit is two output leads of transformer.
(4) due to the empty short characteristic of amplifier, Current Transformer Secondary side is equivalent to short-circuit condition, and secondary side current flows through amplifier outfan through platinum resistance 10, and the magnitude of voltage U=-I*R, I of amplifier outfan is Current Transformer Secondary side electric current.The precision of output valve is the most relevant with the precision of the precision of Zero flux transformer, resistance, the zero-flux current transformer and 0.01% precision, the temperature drift that use 0.01% are the ± 500 Europe platinum resistance of 2PPM/ DEG C, whole device precision can be made to reach 0.02 grade, and output area 0 ~ 6V(exchanges).Amplifier need to select Low-bias Current, and the device of high cmrr, such as OPA277.
(5) owing to, under abnormal conditions, Current Transformer Secondary side there may be stream or device not power-up state, and therefore the input of amplifier designs two reverse diode protection amplifier input potential differences without departing from tolerance.Diode 9 must select the device of low junction capacity, it is ensured that diode will not produce additional effect to the phase place of circuit under normal circumstances.
A kind of reliability high-precision current measuring method, current metering sensor is zero-flux current transformer, uses not opening punching connected mode to access current loop, and current loop electric connecting point (i.e. shielded cable joint) is the most visual；Device has multi-stage protection function and a screened circuit, and protection sensor (i.e. current transformer), circuit will not be under extreme conditions because of open circuit breakage；Current measuring range is the most adjustable；Current measurement precision hardly suffers from the impact of temperature, reaches the level of 0.02 grade.
Zero-flux current transformer accesses and uses punching connected mode, and electric terminal (i.e. shielded cable joint), not inside device, does not increase extra electric terminal, do not changes the line footpath in original loop, increase only the loop length of several centimetres, increases 0.2VA load.Device has multi-stage protection function and screened circuit.In order to ensure that electric terminal is not inside device, sensor is not mounted within inside device, sensor has metal screen layer, sensor is connected by shielded cable with change-over circuit, the integrated short switch of shielded cable joint (the most normally closed travel switch), when sensor union joint (i.e. shielded cable joint) disconnects with change-over circuit, automatic short circuit current transformer circuit.Change-over circuit uses amplifier to build I/V translation circuit, and the input of amplifier when stream crossed by current transformer or device does not power on, will not damage amplifier by two 1N4148 diode clamp protections.Current measuring range is the most adjustable.Current transformer change multiplying power into 1000:1, change the number of turn of external current transformer punching, and the multiplying power of internal I/V conversion, measurement scope can be changed.Generally the maximum punching number of turn is 8.Current measurement precision hardly suffers from the impact of temperature, reaches the level of 0.02 grade.The I/V translation circuit of operational amplifier design and screen layer effectively inhibit common mode disturbances, design to use a noninductive platinum resistance to realize I/V conversion, and U=-I*R, the precision of conversion is only affected by current transformer precision and platinum resistance precision.
A kind of reliability high-precision current measuring method and device is achieved by this utility model; under conditions of can connecting not changing on-the-spot secondary circuit; realize measurement high-precision to loop current; and device possesses multi-stage protection function; ensure that sensor, circuit are not affected by open circuit, power-off; measurement device precision is high, reaches 0.02 grade of level.
The above is only preferred implementation of the present utility model; it is noted that, for those skilled in the art; on the premise of without departing from this utility model principle, it is also possible to make some improvements and modifications, these improvements and modifications also should be regarded as protection domain of the present utility model.
Claims (3)
1. a reliability high-precision current measuring device, including zero-flux current transformer, it is characterized in that, zero-flux current transformer uses not opening punching connected mode to access current loop, zero-flux current transformer is wrapped up by metal shielding, metal shielding connects shielded cable, zero-flux current transformer connects change-over circuit by shielded cable and shielded cable joint, described shielded cable joint is between shielded cable and switching current, and shielded cable joint is integrated with normally closed travel switch.
A kind of reliability high-precision current measuring device the most according to claim 1; it is characterized in that; described change-over circuit uses amplifier to build I/V translation circuit; Current Transformer Secondary side electric current flows through amplifier outfan through platinum resistance, and the input of amplifier is by two 1N4148 diode clamp protection amplifiers.
A kind of reliability high-precision current measuring device the most according to claim 1, it is characterized in that, when shielded cable joint disconnects with change-over circuit, automatic short circuit current transformer secondary side circuit, described change-over circuit is connected with shielded cable joint by connecting seat.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620058160.6U CN205539135U (en) | 2016-01-21 | 2016-01-21 | High reliability high accuracy current measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620058160.6U CN205539135U (en) | 2016-01-21 | 2016-01-21 | High reliability high accuracy current measuring device |
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| CN205539135U true CN205539135U (en) | 2016-08-31 |
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| CN201620058160.6U Active CN205539135U (en) | 2016-01-21 | 2016-01-21 | High reliability high accuracy current measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510679A (en) * | 2016-01-21 | 2016-04-20 | 江苏省电力公司电力科学研究院 | High-reliability and high-precision current measuring method and device |
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2016
- 2016-01-21 CN CN201620058160.6U patent/CN205539135U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510679A (en) * | 2016-01-21 | 2016-04-20 | 江苏省电力公司电力科学研究院 | High-reliability and high-precision current measuring method and device |
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| GR01 | Patent grant |