CN204613359U - A kind of detection system of current transformer for metering secondary circuit state - Google Patents
A kind of detection system of current transformer for metering secondary circuit state Download PDFInfo
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- CN204613359U CN204613359U CN201520348755.0U CN201520348755U CN204613359U CN 204613359 U CN204613359 U CN 204613359U CN 201520348755 U CN201520348755 U CN 201520348755U CN 204613359 U CN204613359 U CN 204613359U
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- 230000010355 oscillation Effects 0.000 description 11
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- 239000003990 capacitor Substances 0.000 description 3
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Abstract
The utility model provides a kind of detection system of current transformer for metering secondary circuit state, comprises and is serially connected in high-frequency voltage signal generation unit between current transformer for metering and electric energy meter, vibration and Resonance detector unit and current detecting unit; High-frequency voltage signal generation unit, vibration and Resonance detector unit and current detecting unit are all connected to single-chip microcomputer; Electric energy meter is connected to single-chip microcomputer by communication unit.Monitoring system of the present utility model can independently be installed in secondary circuit, its simple structure and reliable, can detect the desired data of monitored secondary loop of mutual inductor state in real time, for secondary circuit state analysis provides reliable Data Source.
Description
Technical field
The utility model relates to the monitoring system of current transformer, is specifically related to a kind of detection system of current transformer for metering secondary circuit state.
Background technology
Electric power meter mainly contains voltage transformer (VT), current transformer, secondary circuit and electric energy meter composition.Open circuit in the state of secondary circuit, short circuit and serial connection components and parts are all very important to electric energy metrical.In systems in which, system voltage amplitude is relatively stable, therefore realizes the monitoring to secondary circuit and voltage transformer (VT) state by the supervision of system voltage.And the size of current amplitude changes along with the size variation of load, therefore not by the monitoring of monitoring realization to loop state of amplitude.
Current existing detection system is by being detected the minimum value determination loop state of resonance frequency, but in actual use, the method is for the current transformer of little no-load voltage ratio; Or injected and detection high-frequency signal respectively to secondary loop of mutual inductor by the mode of electromagnetic coupled, measure high-frequency signal by sampling resistor, and judge secondary loop of mutual inductor state according to the change of amplitude; But in actual use, it all exists and almost cannot carry out the problem distinguished, especially current mutual inductor with high transforming ratio by the change of frequency for the open circuit of current transformer and normal operating conditions.Be not suitable for independent installation for secondary circuit status monitoring simultaneously, and the situation of its existence wrong report, effect is undesirable.
Utility model content
In view of this, a kind of detection system of current transformer for metering secondary circuit state that provides of the utility model; This monitoring system can independently be installed in secondary circuit, can detect the desired data of monitored secondary loop of mutual inductor state in real time, for secondary circuit state analysis provides reliable Data Source.
The purpose of this utility model is achieved through the following technical solutions:
A detection system for the secondary circuit state of current transformer for metering, the primary side of described current transformer for metering is connected with power frequency supply, and the secondary side of current transformer for metering is connected with electric energy meter and forms described secondary circuit;
Described system comprises and is serially connected in high-frequency voltage signal generation unit between described current transformer for metering and described electric energy meter, vibrates and Resonance detector unit and current detecting unit;
Described high-frequency voltage signal generation unit, vibration and Resonance detector unit and current detecting unit are all connected to single-chip microcomputer;
Described electric energy meter is connected to described single-chip microcomputer by communication unit.
Preferably, described single-chip microcomputer comprises USB interface, hummer, A/D converter and data processor.
Preferably, described high-frequency voltage signal generation unit comprises operational amplifier and voltage transformer (VT);
Described operational amplifier is connected with described data processor, and in parallel with the secondary side of described voltage transformer (VT);
The primary side of described voltage transformer (VT) is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
Preferably, described vibration and Resonance detector unit comprise phase inverter, capacitance group and the first current transformer;
Described phase inverter is connected with the secondary side of the first current transformer and described data processor respectively;
Described capacitance group is connected with the secondary side of described first current transformer;
The primary side of described first current transformer is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
Preferably, described capacitance group comprises 2 electric capacity of series connection.
Preferably, described current detecting unit comprises sampling resistor and the second current transformer;
Described sampling resistor is connected with the secondary side of described second current transformer and the sampling end of described A/D converter respectively;
The primary side of described second current transformer is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
Preferably, described vibration is connected by digital control simulant electronic switch with Resonance detector unit and described current detecting unit;
Described digital control simulant electronic switch is arranged between the sampling end of described sampling resistor and described A/D converter.
Preferably, described communication unit comprises intelligent instrument and transmission cable.
Preferably, described single-chip microcomputer is connected with display screen and keyboard; Described keyboard is connected with described single-chip microcomputer by interface line; Described display screen is connected with single-chip microcomputer by bus.
As can be seen from above-mentioned technical scheme, the utility model provides a kind of detection system of secondary circuit state of current transformer for metering, comprises and is serially connected in high-frequency voltage signal generation unit between current transformer for metering and electric energy meter, vibration and Resonance detector unit and current detecting unit; High-frequency voltage signal generation unit, vibration and Resonance detector unit and current detecting unit are all connected to single-chip microcomputer; Electric energy meter is connected to single-chip microcomputer by communication unit.Monitoring system of the present utility model can independently be installed in secondary circuit, its simple structure and reliable, can detect the desired data of monitored secondary loop of mutual inductor state in real time, for secondary circuit state analysis provides reliable Data Source.
With immediate prior art ratio, the technical scheme that the utility model provides has following excellent effect:
Technical scheme provided by the utility model, detection system is by being serially connected in the setting of high-frequency voltage signal generation unit between current transformer for metering and electric energy meter, vibration and Resonance detector unit and current detecting unit; This monitoring system is made independently to be installed in secondary circuit, its simple structure and reliable, the desired data of monitored secondary loop of mutual inductor state can be detected in real time, for secondary circuit state analysis provides reliable Data Source, and then ensure that the Stability and dependability of operation of current transformer for metering, can widespread use, there is significant Social benefit and economic benefit.
Accompanying drawing explanation
Fig. 1 is the structural representation of the detection system of a kind of current transformer for metering secondary circuit state of the present utility model;
Fig. 2 is the process flow diagram of the testing process of detection system of the present utility model.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on embodiment of the present utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
In the embodiment shown in fig. 1, application examples of the present utility model provides a kind of detection system of current transformer for metering secondary circuit state, the primary side of current transformer for metering is connected with power frequency supply, and the secondary side of current transformer for metering is connected with electric energy meter and forms secondary circuit;
System comprises and is serially connected in high-frequency voltage signal generation unit between current transformer for metering and electric energy meter, vibration and Resonance detector unit and current detecting unit;
High-frequency voltage signal generation unit, vibration and Resonance detector unit and current detecting unit are all connected to RAM single-chip microcomputer STM32F407;
Electric energy meter is connected to RAM single-chip microcomputer STM32F407 by RS485 communication unit; RAM single-chip microcomputer STM32F407 is also connected with USB interface and hummer.
RAM single-chip microcomputer STM32F407 comprises USB interface, hummer, A/D converter and data processor.
High-frequency voltage signal generation unit comprises operational amplifier OPA227 and voltage transformer pt;
Operational amplifier OPA227 ARM single-chip microcomputer STM32F407 connects, triangular signal is produced by ARM single-chip microcomputer STM32F407, by OPA227 driving voltage mutual inductor winding, and in parallel with the secondary side of the voltage transformer pt of 6:1, voltage transformer pt is used for secondary circuit injecting voltage;
The primary side of voltage transformer pt is serially connected on the secondary circuit between current transformer for metering and electric energy meter;
STM32F407 ARM single-chip microcomputer is connected with OPA227, and synthesized the triangular wave of 20kHz by STM32F407, by the voltage transformer pt of OPA227 Driver injection signal, be the near sinusoidal waveform of 20kHz to CT loop injected frequency, amplitude is 0.4V.
Vibration and Resonance detector unit comprise phase inverter, and the chip model of phase inverter is 74CH14, capacitance group and the first Current Transmit 1;
Phase inverter is that the secondary side of first Current Transmit 1 of 8.4mH and data processor are connected respectively with inductance value;
Capacitance group is connected with the secondary side of the first Current Transmit 1, forms the LC resonant circuit for injecting voltage signal frequency, and forms oscillatory circuit in positive feedback amplifier OPA227;
The primary side of the first Current Transmit 1 is serially connected on the secondary circuit between current transformer for metering and electric energy meter;
When having power current in secondary circuit, the resonance frequency formed with rear class electric capacity of Current Transmit 1 is that the testing circuit of 20kHz will detect the signal obtaining 20kHz and to be connected to by analog signal line the AD sampling end of STM32F407, carries out data processing by STM32F407;
Under being completed be there is no power current situation by STM32F407 in secondary circuit, Current Transmit 1 with rear class electric capacity, the detection of the oscillation frequency of the oscillatory circuit that positive feedback amplifier OPA227 is formed.
Capacitance group comprises 2 electric capacity of series connection.
Current detecting unit comprises the first Current Transmit 2 that sampling resistor and the number of turn are 1000, and Current Transmit 2 is for detecting power current on secondary circuit;
Sampling resistor is connected with the secondary side of the second Current Transmit 2 and the sampling end of A/D converter respectively;
The primary side of the second Current Transmit 2 is serially connected on the secondary circuit between current transformer for metering and electric energy meter;
The two ends of the power current sampling resistor that Current Transmit 2 and sampling resistor are formed are connected by analog signal line with the AD sampling end of STM32F407, and AD sampling end switches the source controlling collection signal by CD4501 multiplex switch.
Vibration is connected by digital control simulant electronic switch CD4051 with Resonance detector unit and current detecting unit;
Digital control simulant electronic switch CD4051 is arranged between sampling resistor and the sampling end of A/D converter.
RS485 communication unit comprises intelligent instrument and transmission cable, and RS485 communication unit adopts MAX485 communication module to realize; STM32F407 is completed and electric energy between electric energy meter by MAX485, the reading of the data such as electric current.
RAM single-chip microcomputer STM32F407 is connected with display screen and keyboard; Keyboard is connected with RAM single-chip microcomputer STM32F407 by I/O interface line, and keyboard is used for the input information of user; 480*320LCD LCDs is connected with RAM single-chip microcomputer STM32F407 by FSMC bus, for showing the information of the secondary circuit state of pick-up unit acquisition, comprising: secondary circuit state, Status Type, can position etc.;
ARM single-chip microcomputer STM32F407 can be connected with acquisition terminal interface by RS485, the data upload that monitoring obtains by acquisition terminal is to parent server, simultaneously monitoring device self also will on screen display status information, and control hummer according to corresponding status information by single-chip microcomputer STM32F407 and produce alerting signal.
As shown in Figure 2, the utility model provides a kind of testing process of detection system of current transformer for metering secondary circuit state to comprise:
Step 1. measures the actual current value I of the check point on secondary circuit
s;
1-1. being connected in series secondary circuit with the primary side of the second Current Transmit 2, the second Current Transmit 2 is positioned at the check point place on secondary circuit; The secondary side of the second Current Transmit 2 is connected with sampling resistor R;
1-2. the second Current Transmit 2 measures the actual current value I of check point
s.
Step 2. compares actual current value I
sthe measurement current value I recorded with electric energy meter
m;
If measure current value I
mwith actual current value I
sabsolute deviation values be more than or equal to deviation standard value, then judge the secondary loop short circuit between check point to electric energy meter, detect terminate;
If absolute deviation values is less than deviation standard value, and actual current value I
sbe not 0, then enter step 3;
If absolute deviation values is less than deviation standard value, and actual current value I
sbe 0, then enter step 5;
Step 3. measures the oscillation frequency value of secondary circuit;
The primary side of secondary circuit with the first Current Transmit 1 is connected in series by 3-1.;
3-2. connects capacitance group and auxiliary circuit respectively at the secondary side of the first Current Transmit 1; Capacitance group comprises the capacitor of 2 series connection, is C1, C2 respectively;
3-3. measures the capacitance of capacitor C1, C2 of 2 series connection;
3-4., by capacitance and the first Current Transmit 1L, calculates the oscillation frequency standard value of secondary circuit
Step 4. compares the oscillation frequency standard value of oscillation frequency value and secondary circuit;
If oscillation frequency value does not exceed oscillation frequency standard value, then judge that secondary circuit state is normal, detect and terminate;
If oscillation frequency value is greater than oscillation frequency standard value, then judge primary side short circuit or the current transformer for metering magnetic saturation of secondary loop short circuit, current transformer for metering, detect and terminate;
Step 5. injects HF voltage in secondary circuit, and detects the actual HF voltage value in secondary circuit;
Secondary circuit is connected in series with the primary side of voltage transformer pt by 5-1.; In the secondary side of voltage transformer pt high frequency signal generator in parallel;
5-2. injects HF voltage by voltage transformer pt in secondary circuit;
The resistance value in the loop that 5-3, the secondary side detecting the first Current Transmit 1 are connected with capacitance group;
5-4, the frequency of HF voltage injected in secondary circuit according to resistance value, the capacitance of capacitor C1, C2 of 2 series connection, voltage transformer pt and the HF voltage value of the first Current Transmit 1, namely the actual HF voltage value calculating the two ends of capacitance group detects C1 and C2 two ends high-frequency voltage signal Ur2, because L and C1, C2 have formed the oscillatory circuit that resonance frequency is f, be that CT1 is coupled the high-frequency signal Ur1's that obtains at C1 and C2 both end voltage Ur2
doubly, wherein R is the resistance value of CT1 and electric capacity C1, C2 series loop.
If the actual HF voltage value of step 6. is 0, then judge that secondary circuit is opened a way, detect and terminate;
If actual HF voltage value is greater than the voltage limits of secondary circuit; Then judge secondary loop short circuit, detect and terminate;
If actual HF voltage value is greater than 0 and does not exceed the voltage limits of secondary circuit; Then judge that secondary circuit state is normal, detect and terminate.
Wherein, deviation standard value is measure current value 5%; Oscillation frequency standard value is 50% of the minimum oscillation frequency constant value of secondary circuit.
Above embodiment is only in order to illustrate that the technical solution of the utility model is not intended to limit; although be described in detail the utility model with reference to above-described embodiment; those of ordinary skill in the field still can modify to embodiment of the present utility model or equivalent replacement; and these do not depart from any amendment of the utility model spirit and scope or equivalent replacement, it is all being applied within the claims of the present utility model awaited the reply.
Claims (9)
1. a detection system for current transformer for metering secondary circuit state, the primary side of described current transformer for metering is connected with power frequency supply, and the secondary side of current transformer for metering is connected with electric energy meter and forms described secondary circuit; It is characterized in that,
Described system comprises and is serially connected in high-frequency voltage signal generation unit between described current transformer for metering and described electric energy meter, vibrates and Resonance detector unit and current detecting unit;
Described high-frequency voltage signal generation unit, vibration and Resonance detector unit and current detecting unit are all connected to single-chip microcomputer;
Described electric energy meter is connected to described single-chip microcomputer by communication unit.
2. detection system as claimed in claim 1, it is characterized in that, described single-chip microcomputer comprises USB interface, hummer, A/D converter and data processor.
3. detection system as claimed in claim 2, it is characterized in that, described high-frequency voltage signal generation unit comprises operational amplifier and voltage transformer (VT);
Described operational amplifier is connected with described data processor, and in parallel with the secondary side of described voltage transformer (VT);
The primary side of described voltage transformer (VT) is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
4. detection system as claimed in claim 2, it is characterized in that, described vibration and Resonance detector unit comprise phase inverter, capacitance group and the first current transformer;
Described phase inverter is connected with the secondary side of the first current transformer and described data processor respectively;
Described capacitance group is connected with the secondary side of described first current transformer;
The primary side of described first current transformer is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
5. detection system as claimed in claim 4, it is characterized in that, described capacitance group comprises 2 electric capacity of series connection.
6. detection system as claimed in claim 2, it is characterized in that, described current detecting unit comprises sampling resistor and the second current transformer;
Described sampling resistor is connected with the secondary side of described second current transformer and the sampling end of described A/D converter respectively;
The primary side of described second current transformer is serially connected on the described secondary circuit between described current transformer for metering and described electric energy meter.
7. detection system as claimed in claim 6, it is characterized in that, described vibration is connected by digital control simulant electronic switch with Resonance detector unit and described current detecting unit;
Described digital control simulant electronic switch is arranged between the sampling end of described sampling resistor and described A/D converter.
8. detection system as claimed in claim 1, it is characterized in that, described communication unit comprises intelligent instrument and transmission cable.
9. detection system as claimed in claim 1, is characterized in that,
Described single-chip microcomputer is connected with display screen and keyboard; Described keyboard is connected with described single-chip microcomputer by interface line; Described display screen is connected with single-chip microcomputer by bus.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104849649A (en) * | 2015-05-26 | 2015-08-19 | 中国电力科学研究院 | System and method for detecting state of secondary circuit of current transformer for metering |
| CN106443304A (en) * | 2016-11-07 | 2017-02-22 | 北京博纳电气股份有限公司 | Method for detecting secondary side loop state of once metering CT on ammeter exterior and detection device |
| CN108362922A (en) * | 2018-01-23 | 2018-08-03 | 宁波三星医疗电气股份有限公司 | CT secondary circuit power theft monitoring methods based on genetic algorithm frequency-selecting |
| CN108663614A (en) * | 2018-07-27 | 2018-10-16 | 柳州和利时科技有限责任公司 | Resistance-capacitance box with exchange track switch indication circuit working state monitoring |
| CN109923424A (en) * | 2016-10-11 | 2019-06-21 | 阿莫善斯有限公司 | Device and method for diagnosing the failure of electromagnetic induction power supply unit |
| CN111650538A (en) * | 2020-05-29 | 2020-09-11 | 深圳供电局有限公司 | Electric energy meter wiring detection device and method |
| CN111650535A (en) * | 2020-05-29 | 2020-09-11 | 深圳供电局有限公司 | Electric energy meter wiring detection method |
| CN114355242A (en) * | 2021-12-24 | 2022-04-15 | 广州南方电力集团科技发展有限公司 | CT secondary side open short circuit detection device and detection method |
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2015
- 2015-05-26 CN CN201520348755.0U patent/CN204613359U/en active Active
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104849649A (en) * | 2015-05-26 | 2015-08-19 | 中国电力科学研究院 | System and method for detecting state of secondary circuit of current transformer for metering |
| CN104849649B (en) * | 2015-05-26 | 2019-03-22 | 中国电力科学研究院 | A kind of detection method of current transformer for metering secondary circuit state |
| CN109923424A (en) * | 2016-10-11 | 2019-06-21 | 阿莫善斯有限公司 | Device and method for diagnosing the failure of electromagnetic induction power supply unit |
| CN109923424B (en) * | 2016-10-11 | 2022-02-25 | 阿莫善斯有限公司 | Apparatus and method for diagnosing a fault in an electromagnetic induction power supply device |
| CN106443304A (en) * | 2016-11-07 | 2017-02-22 | 北京博纳电气股份有限公司 | Method for detecting secondary side loop state of once metering CT on ammeter exterior and detection device |
| CN106443304B (en) * | 2016-11-07 | 2019-06-07 | 北京博纳电气股份有限公司 | For detecting the device and method of primary metering CT secondary side circuit state outside ammeter |
| CN108362922B (en) * | 2018-01-23 | 2020-09-11 | 宁波三星医疗电气股份有限公司 | CT secondary circuit electricity stealing monitoring method based on genetic algorithm frequency selection |
| CN108362922A (en) * | 2018-01-23 | 2018-08-03 | 宁波三星医疗电气股份有限公司 | CT secondary circuit power theft monitoring methods based on genetic algorithm frequency-selecting |
| CN108663614A (en) * | 2018-07-27 | 2018-10-16 | 柳州和利时科技有限责任公司 | Resistance-capacitance box with exchange track switch indication circuit working state monitoring |
| CN111650535A (en) * | 2020-05-29 | 2020-09-11 | 深圳供电局有限公司 | Electric energy meter wiring detection method |
| CN111650538A (en) * | 2020-05-29 | 2020-09-11 | 深圳供电局有限公司 | Electric energy meter wiring detection device and method |
| CN111650535B (en) * | 2020-05-29 | 2022-07-15 | 深圳供电局有限公司 | Electric energy meter wiring detection method |
| CN114355242A (en) * | 2021-12-24 | 2022-04-15 | 广州南方电力集团科技发展有限公司 | CT secondary side open short circuit detection device and detection method |
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