CN206657049U - Power transformer iron core grounding current sample circuit - Google Patents
Power transformer iron core grounding current sample circuit Download PDFInfo
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- CN206657049U CN206657049U CN201720453460.9U CN201720453460U CN206657049U CN 206657049 U CN206657049 U CN 206657049U CN 201720453460 U CN201720453460 U CN 201720453460U CN 206657049 U CN206657049 U CN 206657049U
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- slide rheostat
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 15
- 239000003381 stabilizer Substances 0.000 claims abstract description 11
- 239000003990 capacitor Substances 0.000 claims description 18
- 238000005284 basis set Methods 0.000 claims 1
- 230000005611 electricity Effects 0.000 abstract description 5
- 238000005070 sampling Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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Abstract
Power transformer iron core grounding current sample circuit, belongs to power supply field, and the utility model is to solve the problems, such as that existing transformer core current cailure rate of false positives is high.The utility model：Transformer T secondary side is load output voltage by mu balanced circuit, and sample circuit includes current transformer TA, LA25NP current sensor, amplifier A1, NE555 time-base integrated circuit, auxiliary reclay KA, 7805 voltage stabilizing chips, rectifier bridge, resistance R1~R7, slide rheostat Rp1, slide rheostat Rp2, electric capacity C1~C4 and voltage-stabiliser tube Vs；Series connection auxiliary reclay KA normally-closed contacts in the exchange output loop of mu balanced circuit；Earth fault occurs for transformer core, and its earth current increases severely, and the KA normally-closed contacts for being connected on mu balanced circuit outlet side disconnect, and cut off the loop to secondary side load supplying, are just restored electricity after power circuit is normal.
Description
Technical field
The utility model belongs to power supply field.
Background technology
When multipoint earthing of iron core failure occurs for transformer, iron core grounding current can uprush, on transformer core grounding line
Transformer iron core grounding current on-line monitoring equipment is installed, the earth current of transformer core is monitored in real time, is monitoring
The effective ways of multipoint earthing of iron core.
It is inaccurate due to sampling output result when sample rate current is excessive in actual motion, and then cause equipment rate of false alarm
It is high.
The content of the invention
The purpose of the utility model is to solve the problems, such as that existing transformer core current cailure rate of false positives is high, there is provided one
Kind power transformer iron core grounding current sample circuit.
Power transformer iron core grounding current sample circuit described in the utility model, transformer T secondary side pass through voltage stabilizing
Circuit is load output voltage, and sample circuit includes base when current transformer TA, LA25NP current sensor, amplifier A1, NE555
Integrated circuit, auxiliary reclay KA, 7805 voltage stabilizing chips, rectifier bridge, resistance R1~R7, slide rheostat Rp1, slide rheostat
Rp2, electric capacity C1, electric capacity C2, electrochemical capacitor C3, electrochemical capacitor C4 and voltage-stabiliser tube Vs；
Series connection auxiliary reclay KA normally-closed contacts in the exchange output loop of mu balanced circuit；
Current transformer TA primary coil string is on transformer T iron core, current transformer TA secondary coil difference
5 pin and 6 pin of LA25NP current sensors are connected, 3 pin of LA25NP current sensors connect+15V dc sources, LA25NP electric currents
2 pin of sensor connect -15V dc sources, and 1 pin of LA25NP current sensors is grounded,
The 4 pin connection amplifier A1 of LA25NP current sensors in-phase input end, amplifier A1 in-phase input end pass through electricity
Hinder R1 ground connection；Amplifier A1 inverting input is grounded by resistance R2, in parallel between amplifier A1 inverting input and output end
One ac input end of resistance R3, amplifier A1 output end connection rectifier bridge, another ac input end ground connection of rectifier bridge；
The cathode power supply output end of rectifier bridge connects electric capacity C1 one end, resistance R4 one end and 7805 voltage stabilizing chips simultaneously
1 pin, the negative power supply output end of rectifier bridge connects the electric capacity C1 other end, the resistance R4 other end and 7805 voltage stabilizing cores simultaneously
2 pin of piece, and be grounded；The 3 pin connection slide rheostat Rp1 of a 7805 voltage stabilizing chips fixing end；Slide rheostat Rp1's
Sliding end connects electrochemical capacitor C3 positive pole and 2 pin of NE555 time-base integrated circuits simultaneously；
1 pin of NE555 time-base integrated circuits connects electric capacity C2 one end and electrochemical capacitor C3 negative pole simultaneously；
5 pin of NE555 time-base integrated circuits connect voltage-stabiliser tube Vs anode, electrochemical capacitor C4 negative pole and slided simultaneously to be become
A device Rp2 fixing end is hindered, and is grounded；Slide rheostat Rp2 another fixing end and slide rheostat Rp1 another
Fixing end is connected；
The 4 pin connection slide rheostat Rp2 of NE555 time-base integrated circuits sliding end；
The 6 pin connection resistance R7 of NE555 time-base integrated circuits one end；
8 pin of NE555 time-base integrated circuits connect electrochemical capacitor C4 positive pole, the resistance R7 other end, resistance R6 simultaneously
One end and resistance R5 one end；Resistance R6 other end connection voltage-stabiliser tube Vs negative electrode；
NE555 time-base integrated circuits 3 pin connection auxiliary reclay KA coils one end, auxiliary reclay KA coils it is another
One end connection resistance R5 other end.
Preferably, the single-phase full bridge rectification circuit that rectifier bridge is made up of diode D1~D4.
The advantages of the utility model：Power transformer iron core grounding current sample circuit described in the utility model is applied to big
Current sample, it is simple in construction, reliable working performance, effectively reduce rate of false alarm.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of power transformer iron core grounding current sample circuit described in the utility model.
Embodiment
Embodiment one：Illustrate present embodiment, electrical transformer cores described in present embodiment with reference to Fig. 1
Earth current sample circuit, transformer T secondary side are load output voltage by mu balanced circuit, and it is mutual that sample circuit includes electric current
It is sensor TA, LA25NP current sensor, amplifier A1, NE555 time-base integrated circuit, auxiliary reclay KA, 7805 voltage stabilizing chips, whole
Flow bridge, resistance R1~R7, slide rheostat Rp1, slide rheostat Rp2, electric capacity C1, electric capacity C2, electrochemical capacitor C3, electrochemical capacitor
C4 and voltage-stabiliser tube Vs；
Series connection auxiliary reclay KA normally-closed contacts in the exchange output loop of mu balanced circuit；
Current transformer TA primary coil string is on transformer T iron core, current transformer TA secondary coil difference
5 pin and 6 pin of LA25NP current sensors are connected, 3 pin of LA25NP current sensors connect+15V dc sources, LA25NP electric currents
2 pin of sensor connect -15V dc sources, and 1 pin of LA25NP current sensors is grounded,
The 4 pin connection amplifier A1 of LA25NP current sensors in-phase input end, amplifier A1 in-phase input end pass through electricity
Hinder R1 ground connection；Amplifier A1 inverting input is grounded by resistance R2, in parallel between amplifier A1 inverting input and output end
One ac input end of resistance R3, amplifier A1 output end connection rectifier bridge, another ac input end ground connection of rectifier bridge；
The cathode power supply output end of rectifier bridge connects electric capacity C1 one end, resistance R4 one end and 7805 voltage stabilizing chips simultaneously
1 pin, the negative power supply output end of rectifier bridge connects the electric capacity C1 other end, the resistance R4 other end and 7805 voltage stabilizing cores simultaneously
2 pin of piece, and be grounded；The 3 pin connection slide rheostat Rp1 of a 7805 voltage stabilizing chips fixing end；Slide rheostat Rp1's
Sliding end connects electrochemical capacitor C3 positive pole and 2 pin of NE555 time-base integrated circuits simultaneously；
1 pin of NE555 time-base integrated circuits connects electric capacity C2 one end and electrochemical capacitor C3 negative pole simultaneously；
5 pin of NE555 time-base integrated circuits connect voltage-stabiliser tube Vs anode, electrochemical capacitor C4 negative pole and slided simultaneously to be become
A device Rp2 fixing end is hindered, and is grounded；Slide rheostat Rp2 another fixing end and slide rheostat Rp1 another
Fixing end is connected；
The 4 pin connection slide rheostat Rp2 of NE555 time-base integrated circuits sliding end；
The 6 pin connection resistance R7 of NE555 time-base integrated circuits one end；
8 pin of NE555 time-base integrated circuits connect electrochemical capacitor C4 positive pole, the resistance R7 other end, resistance R6 simultaneously
One end and resistance R5 one end；Resistance R6 other end connection voltage-stabiliser tube Vs negative electrode；
NE555 time-base integrated circuits 3 pin connection auxiliary reclay KA coils one end, auxiliary reclay KA coils it is another
One end connection resistance R5 other end.
The single-phase full bridge rectification circuit that rectifier bridge is made up of diode D1~D4.
Operation principle：
Transformer T primary coil connects AC power, and the break-make of AC power is controlled by circuit breaker Q S.Transformer secondary line
The alternating current of output is enclosed by being load output power supply after mu balanced circuit, the break-make of the working power is by auxiliary reclay KA
Normally-closed contact controls.
Earth current on current transformer TA sensor transformer T iron cores, when the no ground failure of transformer T iron core, its
Earth current is typically within 0.5A, and LA25NP gathers the current output voltage signal, and is amplified by amplifier A1 and exported, the friendship
It is direct current to flow voltage signal rectification, then is exported by 7805 voltage stabilizings, then by Rp1 partial pressures, 2 pin of the magnitude of voltage exported to NE555,
NE555 and periphery electronic component form RS triggering mode of operations, due to voltage-stabiliser tube Vs1 access so that NE555 internal comparators
Reference voltage clamp voltage be about 4V or so.The sampling value that transfinites accesses NE555 2 pin from Rp1 movable end, when ground connection electricity
Flowing small (being less than 0.5A), NE555 2 pin input voltages are less than 2V, and sampling voltage is higher than 0.7V resetting voltage value on 4 pin,
Overturn inside so NE555, its 3 pin output high level, KA coils both ends are high voltage, and KA coils must not be electric, and it is connected on
The normally-closed contact of mu balanced circuit outlet side is kept closed, and transformer exports burning voltage to secondary lateral load.Now power
Normally.
If earth fault occurs for transformer core, its earth current increases severely, and current transformer TA senses high current,
The current value that LA25NP is collected is big, and the magnitude of voltage of output is also big, and NE555 resets, and its 3 pin changes into low level, KA from high level
There is voltage difference in coil both ends, KA coils obtain electric, and it is connected on the normally-closed contact of mu balanced circuit outlet side and disconnected, and cuts off to secondary
The loop of lateral load power supply, just restores electricity after power circuit is normal.
Claims (2)
1. power transformer iron core grounding current sample circuit, transformer T secondary side is electric for load output by mu balanced circuit
Pressure, it is characterised in that sample circuit include current transformer TA, LA25NP current sensor, amplifier A1, NE555 when basis set into
Circuit, auxiliary reclay KA, 7805 voltage stabilizing chips, rectifier bridge, resistance R1~R7, slide rheostat Rp1, slide rheostat Rp2,
Electric capacity C1, electric capacity C2, electrochemical capacitor C3, electrochemical capacitor C4 and voltage-stabiliser tube Vs；
Series connection auxiliary reclay KA normally-closed contacts in the exchange output loop of mu balanced circuit；
On transformer T iron core, current transformer TA secondary coil connects current transformer TA primary coil string respectively
5 pin and 6 pin of LA25NP current sensors, 3 pin of LA25NP current sensors connect+15V dc sources, LA25NP current senses
2 pin of device connect -15V dc sources, and 1 pin of LA25NP current sensors is grounded,
The 4 pin connection amplifier A1 of LA25NP current sensors in-phase input end, amplifier A1 in-phase input end pass through resistance R1
Ground connection；Amplifier A1 inverting input is grounded by resistance R2, parallel resistance between amplifier A1 inverting input and output end
One ac input end of R3, amplifier A1 output end connection rectifier bridge, another ac input end ground connection of rectifier bridge；
The cathode power supply output end of rectifier bridge connects the 1 of electric capacity C1 one end, resistance R4 one end and 7805 voltage stabilizing chips simultaneously
Pin, the negative power supply output end of rectifier bridge connect the electric capacity C1 other end, the resistance R4 other end and 7805 voltage stabilizing chips simultaneously
2 pin, and be grounded；The 3 pin connection slide rheostat Rp1 of a 7805 voltage stabilizing chips fixing end；Slide rheostat Rp1 cunning
Moved end connects electrochemical capacitor C3 positive pole and 2 pin of NE555 time-base integrated circuits simultaneously；
1 pin of NE555 time-base integrated circuits connects electric capacity C2 one end and electrochemical capacitor C3 negative pole simultaneously；
5 pin of NE555 time-base integrated circuits connect voltage-stabiliser tube Vs anode, electrochemical capacitor C4 negative pole and slide rheostat simultaneously
A Rp2 fixing end, and be grounded；Another of slide rheostat Rp2 another fixing end and slide rheostat Rp1 are fixed
End is connected；
The 4 pin connection slide rheostat Rp2 of NE555 time-base integrated circuits sliding end；
The 6 pin connection resistance R7 of NE555 time-base integrated circuits one end；
8 pin of NE555 time-base integrated circuits connect electrochemical capacitor C4 positive pole, the resistance R7 other end, the one of resistance R6 simultaneously
End and resistance R5 one end；Resistance R6 other end connection voltage-stabiliser tube Vs negative electrode；
One end of the 3 pin connection auxiliary reclay KA coils of NE555 time-base integrated circuits, the other end of auxiliary reclay KA coils
Connect the resistance R5 other end.
2. power transformer iron core grounding current sample circuit according to claim 1, it is characterised in that rectifier bridge is by two
The single-phase full bridge rectification circuit that pole pipe D1~D4 is formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720453460.9U CN206657049U (en) | 2017-04-26 | 2017-04-26 | Power transformer iron core grounding current sample circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720453460.9U CN206657049U (en) | 2017-04-26 | 2017-04-26 | Power transformer iron core grounding current sample circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206657049U true CN206657049U (en) | 2017-11-21 |
Family
ID=60319740
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720453460.9U Expired - Fee Related CN206657049U (en) | 2017-04-26 | 2017-04-26 | Power transformer iron core grounding current sample circuit |
Country Status (1)
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| CN (1) | CN206657049U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108879967A (en) * | 2018-09-19 | 2018-11-23 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switch trip warning system |
| CN108900009A (en) * | 2018-09-19 | 2018-11-27 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switch trip alarm device |
| CN109560526A (en) * | 2018-09-19 | 2019-04-02 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switching current alarm device |
-
2017
- 2017-04-26 CN CN201720453460.9U patent/CN206657049U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108879967A (en) * | 2018-09-19 | 2018-11-23 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switch trip warning system |
| CN108900009A (en) * | 2018-09-19 | 2018-11-27 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switch trip alarm device |
| CN109560526A (en) * | 2018-09-19 | 2019-04-02 | 广东电网有限责任公司 | A kind of power distribution station outlet branch line switching current alarm device |
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|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171121 Termination date: 20180426 |
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| CF01 | Termination of patent right due to non-payment of annual fee |