CN201184891Y - Detection module for short/open circuit of current mutual inductor secondary circuit - Google Patents

Detection module for short/open circuit of current mutual inductor secondary circuit Download PDF

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Publication number
CN201184891Y
CN201184891Y CNU2008200821094U CN200820082109U CN201184891Y CN 201184891 Y CN201184891 Y CN 201184891Y CN U2008200821094 U CNU2008200821094 U CN U2008200821094U CN 200820082109 U CN200820082109 U CN 200820082109U CN 201184891 Y CN201184891 Y CN 201184891Y
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CN
China
Prior art keywords
circuit
loop
winding
comparer
mutual inductor
Prior art date
Application number
CNU2008200821094U
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Chinese (zh)
Inventor
俞盛荣
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俞盛荣
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Priority to CNU2008200821094U priority Critical patent/CN201184891Y/en
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Publication of CN201184891Y publication Critical patent/CN201184891Y/en

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Abstract

The utility model relates to monitoring technology field of power meters and discloses a secondary loop short circuit/open circuit detection module of a current transformer. The secondary loop short circuit/open circuit detection module is composed of a high electric frequency power supply, a three-winding transformer, a differential current detection circuit, an impedance sampling circuit and a comparator. When the impedance sampling circuit obtains the information of secondary short circuit or open circuit of the current transformer, the information is immediately transmitted to the differential current detection circuit, and a prompt message is actively issued after the identification and the confirmation by the comparator. The secondary loop short circuit/open circuit detection module adopts the special circuit of external information and internal identification, thereby being able to accurately identify the reasons of sudden drop of current which is input in the billing power meter, carrying out the active, the rapid and the accurate report of the current drop caused by electricity stealing activities and not reflecting the change of load current of a user. The circuit is simple and the cost is low.

Description

Secondary loop of mutual inductor weak point/open circuit detection module
Technical field
The utility model relates to electronic electric energy meter and makes the field.Be specifically a kind of secondary loop of mutual inductor short online detection, discriminating, the special module of prompting of open circuit abnormal information.
Technical background
Both at home and abroad each large-scale power user's electric energy metrical mode all is that this user tens is transformed into the standard electric current that secondary is 5A or 1A to the load current Current Transformer of several kiloamperes, and then delivers to electric energy meter and go metering.The measuring principle of electric energy meter is the integration of power, and power then is the product of voltage, electric current, power factor, i.e. W=UICOS φ.Therefore, the user can reduce these three kinds of methods of voltage, electric current or power factor that electric energy meter collects by technological means, reduces power, realizes the purpose of stealing.In the present technology outage is pressed (decompression), changed phase place stealing electricity methods such as (negative phase sequences etc.), comparatively effectively detection method is all arranged, but the stealing electricity method that reduces electric current is still lacked effective detection reminding method.
Making the short open circuit of secondary loop of mutual inductor, is a kind of effective electricity filching means that reduces to be input to the electric energy meter electric current.And the user is owing to produce to need, and is about to load certainly descend, as closes down several consumers, the electric current that is input in the electric energy meter is reduced, but this belongs to normal power mode.This electric current of two types reduces, and also is difficult at present distinguish on the electric energy meter manufacturing technology.So the electronic electric energy meter of supplying on the market, no matter be import or homemade, do not possess to secondary loop of mutual inductor short abnormal information prompting, the warning function of open circuit.
Employing make secondary loop of mutual inductor short the method stealing of open circuit, method is simple, operational risk is little.Since can not find exactly at present, very harmful.Bring enormous economic loss to country.
Summary of the invention
The objective of the invention is to solve existing above-mentioned deficiency in the prior art, provide a kind of secondary loop of mutual inductor short the open circuit detection module, can realize the independent detection secondary loop of mutual inductor short open circuit information so that send prompting or report to the police.
The technical solution adopted in the present invention is: secondary loop of mutual inductor short the open circuit detection module, form by high frequency electric source, three-winding transformer, difference leakage resistance, comparer, filter capacitor.
Described high frequency electric source output terminal comprises H, L two ends, and described L end links to each other with the non-polar end of first winding of described three-winding transformer, and described H end links to each other with the second winding non-polar end of a difference leakage resistance and described three-winding transformer.The other end of described poor leakage resistance links to each other with the polar end of described first and second winding of three-winding transformer and ground connection, forms the difference current detection circuit.
After the current sampling element is connected in the tertiary winding of described three-winding transformer and the electric energy meter, be serially connected in secondary loop of mutual inductor, formation impedance sample circuit.
The input anode of the input negative terminal of first comparer and second comparer is connected the non-earth terminal of poor leakage resistance simultaneously in the described comparer, form transformer secondary circuit short open circuit information differentiate, cue circuit.
The impedance of the online detection secondary loop of mutual inductor of this module, when impedance changed, comparer was initiatively sent abnormal information.When secondary loop of mutual inductor was short-circuited or opens a way, the comparer output level changed, and initiatively sends the abnormal information cue.
According to transformer working principle, when omitting the static exciter loss, the electric current that flows to first winding equals to flow out the electric current sum of second and third winding, that is:
I 1=I 2+I 3…… (a)
Because in the difference current detection circuit, first winding is that same polarity is docked with second winding, so flow through their common branch---the electric current Δ I that difference flows back to the road is I 1With I 2Poor, that is:
ΔI=I 1-I 2…… (b)
With a formula substitution b formula: Δ I=I 1-I 2=I 3(c)
Because the tertiary winding is serially connected in secondary loop of mutual inductor, when big variation does not take place in the secondary loop of mutual inductor load, I 3Substantially constant.
The pressure drop Δ U at described poor leakage resistance two ends is decided by Δ I, because I 3Substantially constant, Δ I also remains unchanged, and the sampling voltage of described comparer is come the voltage Δ U on the autodyne leakage resistance, so the positive and negative voltage ratio of comparator input terminal does not become, comparer keeps virgin state constant.When secondary loop of mutual inductor take place short during open circuit, the impedance loop of the tertiary winding changes, I 3Ensue variation.According to the c formula as can be known, Δ I also changes, and the voltage that then described comparer is taked also changes, and the comparer output level changes thereupon, sends the abnormal information prompting.
Because sample circuit of the present utility model only is connected in the secondary loop of mutual inductor, when electricity consumption load current size changes, because do not influence the change of secondary loop of mutual inductor impedance, so saltus step does not take place the comparer output level.Therefore realized distinguishing the electric current variation that electric current that the short open circuit because of secondary loop of mutual inductor causes changes and cause because of load variations.
As further improvement of the utility model, the output terminal of two comparers meets a filter capacitor C respectively, to eliminate the interference that temporary impact brings and to filter flat comparer output voltage.
The utility model detection module can be used for single-phase electric energy meter, also can be used for three-phase electric energy meter, when being used for three electric energy meters, can adopt three detection modules of the present utility model, is respectively applied for to detect three phase lines; Also can adopt the utility model detection module, regularly switch, realize detection successively three phase lines by switch.
The utility model adopts the circuit of unique " external information; the inner discriminating ", can discern exactly and be input to the reason that the interior electric current of charge electric energy table descends suddenly, the electric current that " electricity filching behavior " caused descends initiatively, reports rapidly, accurately, and variation does not reflect to the customer charge electric current.And circuit is simple, and cost is low.In addition, because prompting mode is by the saltus step of comparer output level, so can start the LED liquid crystal display easily or light light emitting diode.
Description of drawings
Fig. 1 is, the utility model secondary loop of mutual inductor short the circuit diagram of open circuit detection module.
Embodiment
Below in conjunction with accompanying drawing the utility model is further described.
With reference to Fig. 1, the utility model comprises high frequency electric source (E), three-winding transformer (T), comparer (B 1, B 2), filter capacitor (C), difference leakage resistance (R), described high frequency electric source (E) is used for three-winding transformer (T) is injected detection signal, its iron core working band is 10--20KC.Described three-winding transformer (T) and difference leakage resistance (R) and and the inner sampling of electric energy meter original paper (T A) formation difference current detection circuit and impedance sample circuit.First winding (the W wherein 1) and the second winding (W 2) be 100-200 circle, the tertiary winding (W 3) be the 1-2 circle.Described comparer (B 1, B 2) be used for the output current transformer secondary circuit short open circuit information.Described poor leakage resistance (R) will differ from circulation and be changed to differential pressure Δ U, offer comparer (B 1, B 2) (B 1, B 2) sampling.
Secondary loop of mutual inductor do not take place short under the open-circuit condition, set difference leakage resistance (R) two end pressure drop Δ U=Δ U Often, and set the positive terminal voltage E of input of first comparer 1=1.5 Δ U Often, the input negative terminal E of second comparer 2=0.5 Δ U Often
Because three-winding transformer selects high-frequency core for use, the signal beyond the working band is decayed substantially 50 all power frequency components especially, the tertiary winding (W 3) be coupled to the first winding (W 1), the second winding (W 2), so the electric current Δ I that flows through on difference leakage resistance (R) all is a high-frequency signal.
According to the c formula, difference stream Δ I and the tertiary winding (W 3) loop current I 3Equate, when the secondary loop of mutual inductor impedance is constant, I 3Stablize constantly, Δ U also maintains certain order of magnitude; According to design parameter, E 1=1.5 Δ U Often, E2=0.5 Δ U Often, when the secondary loop of mutual inductor impedance did not take place to change greatly, the positive terminal voltage of comparator input terminal was higher than negative terminal voltage, output low level " 0 ".
When secondary loop of mutual inductor is short-circuited, the tertiary winding (W 3) impedance loop declines to a great extent I 3Rise, Δ I increases, Δ U>>1.5 Δ U Often, the first comparer (B 1) input positive terminal voltage be lower than input negative terminal voltage, that is: E 1<Δ U, the first comparer (B 1) action, output high level " 1 " sends " secondary loop of mutual inductor short circuit " information.Second comparer (the B 2) input positive terminal voltage be higher than the input negative terminal voltage, output level is constant.
When open circuit takes place in secondary loop of mutual inductor, the tertiary winding (W 3) impedance loop becomes infinity, I 3=0, Δ U descends, Δ U<<0.5 Δ U Often, the first comparer (B 1) input negative terminal voltage be lower than the input positive terminal voltage, output level is constant.Second comparer (the B 2) the positive terminal voltage of input is lower than the input negative terminal voltage, that is: Δ U<E 2, high level " 1 " is changed in output, sends " secondary loop of mutual inductor open circuit " information.
As the above analysis, as long as the secondary loop of mutual inductor impedance is undergone mutation, this module just can be reported to the police immediately.Because the level saltus step is adopted in prompting, so can start the LED liquid crystal display easily or light light emitting diode.After abnormal information was removed, prompting was eliminated automatically.
What should be understood that is that the foregoing description is to explanation of the present utility model, rather than to restriction of the present utility model, any innovation and creation that do not exceed in the utility model connotation scope all fall into the utility model protection domain.

Claims (3)

1. the short open circuit of a secondary loop of mutual inductor detection module is characterized in that, comprises high frequency electric source (E), three-winding transformer (T), difference leakage resistance (R), the first comparer (B 1), the second comparer (B 2) form, the output terminal of described high frequency electric source (E) comprises H, L two ends, the first winding (W of described L end and described three-winding transformer (T) 1) non-polar end link to each other described H end and an end of described poor leakage resistance (R) and the second winding (W of described three-winding transformer (T) 2) non-polar end links to each other; First winding (the W of the other end of described poor leakage resistance (R) and described three-winding transformer (T) 1) and the second winding (W 2) polar end link to each other and ground connection; The tertiary winding (the W of described three-winding transformer (T) 3) and the interior current sampling element (T of electric energy meter A) after the connection, be serially connected in secondary loop of mutual inductor; The described first comparer (B 1) the input negative terminal and the second comparer (B 2) the input anode be connected the non-earth terminal of poor leakage resistance (R) simultaneously.
2. secondary loop of mutual inductor as claimed in claim 1 short the open circuit detection module, it is characterized in that described comparer (B 1, B 2) output terminal all be connected to a filter capacitor (C).
3. secondary loop of mutual inductor as claimed in claim 2 short the open circuit detection module, it is characterized in that when secondary loop of mutual inductor was not short-circuited or opens a way, setting difference leakage resistance (R) two terminal voltage Δ U was Δ U Often, and set the first comparer (B 1) the positive terminal voltage E of input 1Be 1.5 Δ U Often, the second comparer (B 2) input negative terminal voltage E 2Be 0.5 Δ U Often
CNU2008200821094U 2008-01-11 2008-01-11 Detection module for short/open circuit of current mutual inductor secondary circuit CN201184891Y (en)

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CNU2008200821094U CN201184891Y (en) 2008-01-11 2008-01-11 Detection module for short/open circuit of current mutual inductor secondary circuit

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Application Number Priority Date Filing Date Title
CNU2008200821094U CN201184891Y (en) 2008-01-11 2008-01-11 Detection module for short/open circuit of current mutual inductor secondary circuit

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101968524A (en) * 2010-09-30 2011-02-09 王道龙 Division test method and tester for multi-point grounding of common loop
CN102520309A (en) * 2011-12-07 2012-06-27 宁波三星电气股份有限公司 Method for judging open circuit of secondary loop of current transformer
CN102798838A (en) * 2012-08-29 2012-11-28 重庆市电力公司电力科学研究院 Pluggable safety junction box for site calibration of electric energy meter
CN103257301A (en) * 2013-04-28 2013-08-21 国家电网公司 Current sealing detection device
CN103956714A (en) * 2014-04-24 2014-07-30 合肥沃华电气技术有限公司 High-sensitivity multifunctional CT open circuit protection device
CN104297611A (en) * 2014-01-14 2015-01-21 河南许继智能控制技术有限公司 Transformer sampling circuit
CN105938153A (en) * 2016-03-03 2016-09-14 中国电力科学研究院 System for monitoring abnormal state of CT secondary loop and electricity stealing prevention method
CN106872928A (en) * 2017-01-19 2017-06-20 宁波三星医疗电气股份有限公司 The electric energy meter and self checking method of a kind of electric energy self checking
CN107015095A (en) * 2017-03-23 2017-08-04 中国电力科学研究院 A kind of method and system that secondary loop of mutual inductor state is judged based on Transient Method
CN109980601A (en) * 2017-12-28 2019-07-05 国网江苏省电力公司常州供电公司 Electromagnetic current transducer secondary circuit protective device
CN110133349A (en) * 2019-06-04 2019-08-16 河南工业大学 Anti- shunting stealing electricity method based on alien frequencies method
CN111999677A (en) * 2020-10-28 2020-11-27 江苏智臻能源科技有限公司 Indoor and outdoor short circuit identification method based on meter box monitoring terminal and intelligent electric meter

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101968524A (en) * 2010-09-30 2011-02-09 王道龙 Division test method and tester for multi-point grounding of common loop
CN102520309A (en) * 2011-12-07 2012-06-27 宁波三星电气股份有限公司 Method for judging open circuit of secondary loop of current transformer
CN102798838A (en) * 2012-08-29 2012-11-28 重庆市电力公司电力科学研究院 Pluggable safety junction box for site calibration of electric energy meter
CN103257301A (en) * 2013-04-28 2013-08-21 国家电网公司 Current sealing detection device
CN104297611A (en) * 2014-01-14 2015-01-21 河南许继智能控制技术有限公司 Transformer sampling circuit
CN103956714A (en) * 2014-04-24 2014-07-30 合肥沃华电气技术有限公司 High-sensitivity multifunctional CT open circuit protection device
CN103956714B (en) * 2014-04-24 2016-09-07 合肥沃华电气技术有限公司 A kind of high sensitivity multi-functional CT open-circuit protecting device
CN105938153A (en) * 2016-03-03 2016-09-14 中国电力科学研究院 System for monitoring abnormal state of CT secondary loop and electricity stealing prevention method
CN106872928A (en) * 2017-01-19 2017-06-20 宁波三星医疗电气股份有限公司 The electric energy meter and self checking method of a kind of electric energy self checking
CN106872928B (en) * 2017-01-19 2019-04-12 宁波三星医疗电气股份有限公司 A kind of electric energy meter and self checking method of electric energy self checking
CN107015095A (en) * 2017-03-23 2017-08-04 中国电力科学研究院 A kind of method and system that secondary loop of mutual inductor state is judged based on Transient Method
CN109980601A (en) * 2017-12-28 2019-07-05 国网江苏省电力公司常州供电公司 Electromagnetic current transducer secondary circuit protective device
CN110133349A (en) * 2019-06-04 2019-08-16 河南工业大学 Anti- shunting stealing electricity method based on alien frequencies method
CN111999677A (en) * 2020-10-28 2020-11-27 江苏智臻能源科技有限公司 Indoor and outdoor short circuit identification method based on meter box monitoring terminal and intelligent electric meter

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20090121

Termination date: 20160111