CN106451325A - Protective circuit for microcomputer type relay protection device - Google Patents
Protective circuit for microcomputer type relay protection device Download PDFInfo
- Publication number
- CN106451325A CN106451325A CN201610988171.9A CN201610988171A CN106451325A CN 106451325 A CN106451325 A CN 106451325A CN 201610988171 A CN201610988171 A CN 201610988171A CN 106451325 A CN106451325 A CN 106451325A
- Authority
- CN
- China
- Prior art keywords
- operational amplifier
- circuit
- type relay
- protection device
- relay protection
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
A protective circuit for a microcomputer type relay protection device comprises an operational amplifier, a resistor and an adjustable resistor, wherein the reverse-phase input end of the operation amplifier is connected with a digital ground wire through the first resistor; one end of the adjustable resistor is connected with the reverse-phase input end of the operation amplifier and the other end of the adjustable resistor is connected with the output end of the operation amplifier; the in-phase input end of the operational amplifier is the input end of the circuit and is connected with the output end of an analog-digital convertor A/D; and the output end of the operational amplifier is the output end of the circuit and is connected with the input end of the microcomputer type relay protection device. The protective circuit for the microcomputer type relay protection device provided by the invention has the effects that an in-phase operation amplification circuit is added in front of the microcomputer type relay protection device and a small resistance grounded current signal is amplified, so that the output signal can easily meet the sensitivity requirement of the microcomputer type relay protection device.
Description
Technical field
The invention belongs to technical field of relay protection, more particularly to a kind of protection for microcomputer based relay protective device
Circuit.
Background technology
In transformer station's straight-flow system one point earth line selection apparatus, (principle is to believe to straight-flow system injection low pressure low-frequency ac
Number, generally 10V, 10HZ) and power distribution network Little Current Ground Connection System in, after circuit single phase ground fault, such as
Fruit earth point can produce earth current numerical value very little when resistance eutral grounding, easily beyond the measurement range of protection device so that
Computerized protection cannot ensure the accuracy of earthing detection, cause erroneous judgement or according to dynamic problem.
Content of the invention
In order to solve the above problems, it is an object of the invention to provide a kind of protection for microcomputer based relay protective device
Circuit.
In order to achieve the above object, the protection circuit provided by the present invention for microcomputer based relay protective device includes：Fortune
Calculate amplifier A, resistance R1 and adjustable resistance Rf；Wherein：The inverting input of operational amplifier A is by first resistor R1 and numeral
Ground wire connects, adjustable resistance RfOne end be connected with the inverting input of operational amplifier A, its other end and operational amplifier A
Outfan connection；The in-phase input end of operational amplifier A is the input of this circuit, the outfan with modulus converter A/D
Connection, the outfan of operational amplifier A is the outfan of this circuit, is connected with the input of microcomputer based relay protective device.
Described first resistor R1 is 2k Ω resistor, adjustable resistance RfFor rheostat, resistance is taken at 0～150k
Ω.
Effect provided by the present invention for the protection circuit of microcomputer based relay protective device：
It is one homophase operational amplification circuit of addition before microcomputer based relay protective device, can be by the little electricity of resistance grounded
Stream signal amplification so that output signal can be easily met the requirement of microcomputer based relay protective device sensitivity.
Description of the drawings
Fig. 1 is the structural representation of the protection circuit provided by the present invention for microcomputer based relay protective device.
Specific embodiment
Below in conjunction with the accompanying drawings with specific embodiment to the protection electricity provided by the present invention for microcomputer based relay protective device
Road is described in detail.
As shown in figure 1, the protection circuit provided by the present invention for microcomputer based relay protective device is arranged on analog digital conversion
Between device A/D and microcomputer based relay protective device, it is a homophase operational amplification circuit, protection signal can be amplified；
Which includes：Operational amplifier A, resistance R1 and adjustable resistance Rf；Wherein：The inverting input of operational amplifier A leads to
Cross first resistor R1 to be connected with digital ground wire, adjustable resistance RfOne end be connected with the inverting input of operational amplifier A, which is another
One end is connected with the outfan of operational amplifier A；The in-phase input end of operational amplifier A is the input of this circuit, with modulus
The outfan connection of transducer A/D, the outfan of operational amplifier A is the outfan of this circuit, fills with microcomputer type relay protection
The input connection that puts.
Amplification Au=1+ (Rf/R1) of the described protection circuit for microcomputer based relay protective device, i.e. Usc=
[1+(Rf/R1)]Usr.Wherein first resistor R1 is 2k Ω resistor, adjustable resistance RfFor rheostat, resistance is taken at 0～
150kΩ.General amplification Au=30～50 can meet sensitivity requirement.Because this circuit adopts homophase operational amplification circuit,
So circuit input Usr and circuit output Usc phase.
Protection circuit provided by the present invention for microcomputer based relay protective device can be by the small current of resistance grounded
Signal amplifies so that output signal can be easily met the requirement of microcomputer based relay protective device sensitivity.
Claims (2)
1. a kind of protection circuit for microcomputer based relay protective device, it is characterised in that：Described protects for microcomputer type relay
The protection circuit of protection unit includes：Operational amplifier A, resistance R1 and adjustable resistance Rf；Wherein：Operational amplifier A anti-phase defeated
Enter end to be connected with digital ground wire by first resistor R1, adjustable resistance RfOne end and operational amplifier A inverting input even
Connect, its other end is connected with the outfan of operational amplifier A；The in-phase input end of operational amplifier A is the input of this circuit,
It is connected with the outfan of modulus converter A/D, the outfan of operational amplifier A is the outfan of this circuit, with microcomputer type relay
The input connection of protection device.
2. the protection circuit for microcomputer based relay protective device according to claim 1, it is characterised in that：Described
One resistance R1 is 2k Ω resistor, adjustable resistance RfFor rheostat, resistance is taken at 0～150k Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610988171.9A CN106451325A (en) | 2016-11-09 | 2016-11-09 | Protective circuit for microcomputer type relay protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610988171.9A CN106451325A (en) | 2016-11-09 | 2016-11-09 | Protective circuit for microcomputer type relay protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106451325A true CN106451325A (en) | 2017-02-22 |
Family
ID=58208305
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610988171.9A Pending CN106451325A (en) | 2016-11-09 | 2016-11-09 | Protective circuit for microcomputer type relay protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106451325A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110514891A (en) * | 2019-09-04 | 2019-11-29 | 珠海西格电力科技有限公司 | A kind of microcomputer current detection means |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000258469A (en) * | 1999-03-11 | 2000-09-22 | Mitsubishi Electric Corp | Electric power system protection and control device |
| CN101499650A (en) * | 2009-03-10 | 2009-08-05 | 南京因泰莱配电自动化设备有限公司 | Small current earthing wire selection protection apparatus and protection method based on GPRS |
| CN101846715A (en) * | 2009-03-27 | 2010-09-29 | 北海银河科技继保电气有限公司 | Low-current ground fault line selection device and multi-platform combined line selection method |
| CN202033448U (en) * | 2011-03-18 | 2011-11-09 | 华北电力大学 | Undercurrent earth fault line selection apparatus base on embedded technology |
| CN202471891U (en) * | 2011-11-23 | 2012-10-03 | 广州东芝白云菱机电力电子有限公司 | DC feeder line small current grounding line selection device for DC power cabinet |
| CN204989385U (en) * | 2015-08-03 | 2016-01-20 | 京泰尔联电气（北京）有限公司 | Earth fault AD signal processing system of undercurrent system |
-
2016
- 2016-11-09 CN CN201610988171.9A patent/CN106451325A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000258469A (en) * | 1999-03-11 | 2000-09-22 | Mitsubishi Electric Corp | Electric power system protection and control device |
| CN101499650A (en) * | 2009-03-10 | 2009-08-05 | 南京因泰莱配电自动化设备有限公司 | Small current earthing wire selection protection apparatus and protection method based on GPRS |
| CN101846715A (en) * | 2009-03-27 | 2010-09-29 | 北海银河科技继保电气有限公司 | Low-current ground fault line selection device and multi-platform combined line selection method |
| CN202033448U (en) * | 2011-03-18 | 2011-11-09 | 华北电力大学 | Undercurrent earth fault line selection apparatus base on embedded technology |
| CN202471891U (en) * | 2011-11-23 | 2012-10-03 | 广州东芝白云菱机电力电子有限公司 | DC feeder line small current grounding line selection device for DC power cabinet |
| CN204989385U (en) * | 2015-08-03 | 2016-01-20 | 京泰尔联电气（北京）有限公司 | Earth fault AD signal processing system of undercurrent system |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110514891A (en) * | 2019-09-04 | 2019-11-29 | 珠海西格电力科技有限公司 | A kind of microcomputer current detection means |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170222 |