CN2399735Y - Computer controlled insulation monitor - Google Patents
Computer controlled insulation monitor Download PDFInfo
- Publication number
- CN2399735Y CN2399735Y CN 99229193 CN99229193U CN2399735Y CN 2399735 Y CN2399735 Y CN 2399735Y CN 99229193 CN99229193 CN 99229193 CN 99229193 U CN99229193 U CN 99229193U CN 2399735 Y CN2399735 Y CN 2399735Y
- Authority
- CN
- China
- Prior art keywords
- circuit
- operational amplifier
- leakage current
- sampling resistor
- current acquisition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000009413 insulation Methods 0.000 title abstract description 28
- 238000005070 sampling Methods 0.000 claims abstract description 9
- 238000013519 translation Methods 0.000 claims description 5
- 238000012806 monitoring device Methods 0.000 claims description 4
- 238000002955 isolation Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 230000035945 sensitivity Effects 0.000 abstract 1
- 238000012544 monitoring process Methods 0.000 description 6
- 238000004891 communication Methods 0.000 description 4
- 230000002950 deficient Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- Measurement Of Resistance Or Impedance (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The utility model relates to a computer controlled DC insulation monitor, which comprises a leakage current acquisition circuit (1), an A/D conversion circuit (2), a microprocessor control circuit (3), a keyboard and a display circuit (4). The positive bus-bar end and the negative bus-bar end of the leakage current acquisition circuit (1) are respectively connected in series with resistors (R1 and R2), and a relay connection point is connected with a sampling resistor (R3). The leakage current acquisition circuit (1) is provided with operational amplifiers (A1 and A2), and the two input ends of the operational amplifiers bridge on the both ends of the sampling resistor. The output ends of the operational amplifiers are connected with the microprocessor control circuit. The utility model provides a computer controlled insulation monitor which has the advantage of high sensitivity and respectively displays the insulation resistance to the ground of the positive bus-bar and the negative bus-bar.
Description
The utility model belongs to the manufacturing of power equipment, relates to a kind of device that DC power-supply system such as transformer station, generating plant monitored and monitored dc bus insulation against ground situation that is used for.
Become power supply and generating plant (station) for safety, usually will carry out insulation against ground to the bus of direct current supply monitors, and for a long time, the insulation monitoring and warning device of use is to adopt the bridge balance principle to judge the resistance of positive and negative dc feeder insulation against ground, in order to judge dc bus insulation against ground situation.Its shortcoming is: owing to adopt bridge circuit, one side bridge circuit is fixed resistance, the another side of bridge circuit is the positive and negative end resistance to earth of dc bus, when one of bus brings out existing defective insulation, the bridge out of trim, when its value acquired a certain degree, the actuating of relay was reported to the police.This shows that when bridge circuit two ends insulation resistance all descended, bridge circuit was reached another kind of balance, at this moment, just can not report to the police, also be easy to generate wrong report.Simultaneously, existing insulation monitoring and warning device can only be a kind of monitoring qualitatively, there is no quantitative demonstration, relies on highly sensitive relay setting working value to be difficult to accurately, and error is big.In the use; the situation that regular meeting wrong report occurs or do not report; had a strong impact on equipment safety operation; domestic have some improved direct current monitoring devices: it is to adopt photodiode inspection stream; promptly differentiate the size of insulation resistance, set alarming value with circuit and solved the defective of using supersensitive relay in the past from the electric current that flows through photodiode.But its shortcoming is, still do not have the demonstration of insulation resistance value, the 2nd, and the photodiode temperature influence is big.
This practical purpose is: a kind of highly sensitive computer control insulation monitoring and warning device that shows positive and negative bus insulation against ground resistance respectively is provided, and is a kind of insulation monitoring and warning device of being set alarming value by numeral.
The purpose of this utility model is achieved in that a kind of computer control D.C. isolation monitoring device, comprise leakage current Acquisition Circuit (1), A/D translation circuit (2), microprocessor control circuit (3), keyboard, display circuit (4) composition, it is characterized in that being constructed as follows of leakage current Acquisition Circuit (1): from positive and negative busbar end difference series resistor (R
1, R
2) and relay tip be connected to sampling resistor (R
3), be provided with operational amplifier (A1), its two input end is connected across the two ends of sampling resistor respectively, other is provided with operational amplifier (A2), its two input ends anode and negative terminal are connected across the two ends of sampling resistor respectively on the contrary, the output terminal of two operational amplifiers is imported A/D translation circuit (2), microprocessor control circuit (3), the output terminal pilot relay contact of microprocessor control circuit (3) through photoelectric isolating circuit.
The utility model is described in further detail below in conjunction with accompanying drawing and by embodiment:
Fig. 1 is the utility model principle schematic
Fig. 2 is the utility model current acquisition circuit diagram
Fig. 3 is the utility model A/D translation circuit, microprocessor control circuit, display circuit figure
As shown in the figure, among Fig. 1,2, suppose that dc bus insulation against ground resistance is R
+And R
-When bus insulation resistance is big, flow through current sampling resistor R
3Electric current minimum, when the positive bus-bar insulation against ground is bad, R
-Diminish, this moment, voltage just had leakage current I
LeakThrough R
+, R
3, R
2Flow through and at R
3Last generation pressure drop U
R3=I
Leak* R
3, because leakage current and R
3Data all very little, so will pass through high-accuracy operational amplifier A
1Or A
2After the amplification, change into data volume, read and calculate R by microprocessor by the A/D change-over circuit
+Size, otherwise also like this during the negative wire defective insulation.A among the figure
1Anode and A
2Negative terminal be connected A
1Negative terminal and A
2The anode parallel connection, and parallel connection is connected across on the sample resistance.When positive and negative busbar insulating was bad, the size of its leakage current was inversely proportional to the size of insulation resistance.This buffer circuit is a linear photoconductor coupling buffer circuit.
In order when measuring calculating, to reduce measuring error, reduce resistance R
1And R
2To the influence of measuring accuracy, when measuring the positive bus-bar insulation resistance, tripping normally closed contact J
1b, to reduce resistance R
1To R
+The influence that produces in parallel.Because resistance R
1R
2Be far longer than R
3So, R
3Ignore.Otherwise tripping normally closed contact J when measuring the negative busbar insulation resistance
2bTo reduce resistance R
2To R
-The influence that produces in parallel.
Because positive and negative busbar insulating resistance is in case determine, so basic no change is bigness scale insulation resistance just often.Only when accurate measurement, just jump normally closed contact, prolonged the serviceable life of device so greatly, because positive and negative bus is the difference oil mass, so show the insulation resistance (because actual conditions positive and negative busbar resistance to earth is not the same) of positive and negative busbar respectively.
In Fig. 3 circuit diagram, keyboard is used to set the size of insulation resistance warning numerical value, owing to be that digital test and numeral compare, just is not subjected to the influence of reasons such as temperature.Computer control part is made up of microprocessor 97C2051, watchdog circuit 25045 (containing EEPRAM), A/D conversion chip TLC0832 and communication chip MAX202E and MAX485E, control end, address end and the data terminal of microprocessor 97C2051 and watchdog circuit 25045 (containing EEPRAM), A/D conversion chip TLC0832 are connected to each other, and interface can carry out communication with host computer in Fig. 3.Input end from the measuring-signal of the output of Fig. 2 to the A/D conversion chip TLC0832 of Fig. 3, connect microprocessor 97C2051 again, carry out data processing by microprocessor and also connect with host computer (PC), carry out communication by RS232 or RS485 mode by communication chip MAX202E and MAX485E.The output terminal of microprocessor 97C2051 drives relay J by amplifier 2003 in addition
1J
2Action.J
3J
4Be respectively the bad warning output relay of positive and negative busbar insulating.
Claims (2)
1, a kind of computer control D.C. isolation monitoring device, comprise leakage current Acquisition Circuit (1), A/D translation circuit (2), microprocessor control circuit (3), keyboard, display circuit (4) composition, it is characterized in that being constructed as follows of leakage current Acquisition Circuit (1): from positive and negative busbar end difference series resistor (R
1, R
2) and relay tip be connected to sampling resistor (R
3), be provided with operational amplifier (A
1), its two input end is connected across the two ends of sampling resistor respectively, and other is provided with operational amplifier (A
2), its two input ends anode and negative terminal are connected across the two ends of sampling resistor respectively on the contrary, the output terminal of two operational amplifiers is imported A/D translation circuit (2), microprocessor control circuit (3), the output terminal pilot relay contact of microprocessor control circuit (3) through photoelectric isolating circuit.
2, by the described computer control of claim 1 D.C. isolation monitoring device, it is characterized in that operational amplifier (A
1) anode and another operational amplifier (A
2) negative terminal be connected operational amplifier (A
1) negative terminal and operational amplifier (A
2) the anode parallel connection, and parallel connection is connected across on the sample resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99229193 CN2399735Y (en) | 1999-08-18 | 1999-08-18 | Computer controlled insulation monitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99229193 CN2399735Y (en) | 1999-08-18 | 1999-08-18 | Computer controlled insulation monitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2399735Y true CN2399735Y (en) | 2000-10-04 |
Family
ID=34018465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99229193 Expired - Fee Related CN2399735Y (en) | 1999-08-18 | 1999-08-18 | Computer controlled insulation monitor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2399735Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101158701B (en) * | 2007-11-16 | 2010-06-02 | 中国科学院电工研究所 | High voltage system voltage and insulation resistance measurement circuit |
| CN101663589B (en) * | 2007-06-28 | 2012-07-25 | Ll株式会社 | Measuring instrument for a resistive electric leakage current |
| CN103091544A (en) * | 2013-01-21 | 2013-05-08 | 中国人民解放军63963部队 | Direct current electric leakage detection circuit |
| CN106645963A (en) * | 2016-12-27 | 2017-05-10 | 北京天诚同创电气有限公司 | Insulation resistance detection circuit and insulation resistance detection method |
-
1999
- 1999-08-18 CN CN 99229193 patent/CN2399735Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101663589B (en) * | 2007-06-28 | 2012-07-25 | Ll株式会社 | Measuring instrument for a resistive electric leakage current |
| CN101158701B (en) * | 2007-11-16 | 2010-06-02 | 中国科学院电工研究所 | High voltage system voltage and insulation resistance measurement circuit |
| CN103091544A (en) * | 2013-01-21 | 2013-05-08 | 中国人民解放军63963部队 | Direct current electric leakage detection circuit |
| CN103091544B (en) * | 2013-01-21 | 2015-03-25 | 中国人民解放军63963部队 | Direct current electric leakage detection circuit |
| CN106645963A (en) * | 2016-12-27 | 2017-05-10 | 北京天诚同创电气有限公司 | Insulation resistance detection circuit and insulation resistance detection method |
| CN106645963B (en) * | 2016-12-27 | 2019-06-04 | 北京天诚同创电气有限公司 | Insulating resistor detecting circuit and its detection method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |