CN112285618A - Scheme for detecting CT secondary side wiring state - Google Patents
Scheme for detecting CT secondary side wiring state Download PDFInfo
- Publication number
- CN112285618A CN112285618A CN201911322527.5A CN201911322527A CN112285618A CN 112285618 A CN112285618 A CN 112285618A CN 201911322527 A CN201911322527 A CN 201911322527A CN 112285618 A CN112285618 A CN 112285618A
- Authority
- CN
- China
- Prior art keywords
- circuit
- signal
- secondary side
- sampling
- converter
- 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.)
- Withdrawn
Links
Images
Landscapes
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention discloses a scheme for detecting the wiring state of a CT secondary side, which is used for detecting the wiring state of an external CT secondary side by electric energy metering equipment and can realize the state detection of open circuit, short circuit, virtual short and normal connection of the external CT wiring state. The scheme comprises a converter connected in series with a CT secondary side coil, an IC chip for data transmission and sampling, and an MCU chip for data processing. The scheme can effectively realize the detection of the wiring state of the secondary side of the CT, can be used for three-phase metering and the detection of the external CT wiring of the terminal equipment, and improves the electricity larceny prevention level of the equipment.
Description
Technical Field
The invention relates to a method and a circuit for detecting the secondary side wiring state of an external CT (computed tomography) on electric power metering equipment.
Background
At present, with the increase of electricity consumption of power consumers, the load current of many power consumers reaches dozens or even thousands of amperes, and such consumers generally convert the current into 5A or 1A current for metering by installing a current transformer (one-time metering CT) for a three-phase meter or a terminal. Due to factors such as improper construction and electricity stealing by users, abnormal electricity utilization wiring modes such as short circuit, disconnection and virtual short can occur when the three-phase meter or the terminal is connected with the secondary side of the CT, so that not only is the electric power property loss brought to an electric power operation department, but also the open circuit operation of the external CT can enable the CT to be in an abnormal working state, and equipment damage is possibly brought. For the detection of the wiring state of the external CT secondary side, the maintenance work of an electric power operation department can be effectively reduced, and the method has very important significance for electric power safety and electricity larceny prevention.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a solution for detecting a secondary side connection state of a CT, which can detect problems of open circuit, short circuit, etc. of a secondary side connection of an external CT by using a detection circuit and a corresponding converter, and an experimental metering device detects a secondary connection state of an external CT in real time.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the scheme for detecting the wiring state of the secondary side of the CT comprises a detection circuit and a corresponding converter, wherein the detection circuit comprises a signal generation circuit, a signal sampling circuit and a data processing circuit; the converter comprises a signal transmitting part and a signal sampling part.
The detection circuit comprises a signal generation circuit, a signal sampling circuit and a data processing circuit, wherein the signal generation circuit can generate PWM waves with adjustable frequency, a signal sending coil inside the converter and a capacitor connected in parallel form an LC resonance circuit, the LC resonance circuit is driven by the PWM waves, energy is coupled to the detection coil through the converter, a resistor is connected in series outside the detection coil, the coupled current signals can be converted into voltage signals, the output voltage signals are connected to a 24-bit sigma-delta AD sampling pin, analog signals are converted into digital signals, the sampled digital signals are transmitted to an MCU for data processing, the MCU can calculate amplitude signals corresponding to different frequencies through sampled data, and the state of the wiring mode of the secondary side of the CT can be judged through comparison with the stored amplitude values of the detection frequency.
The converter is composed of two magnetic rings, each magnetic ring surrounds 300 circles of enameled wires, the two magnetic rings are connected in a penetrating manner through a lead, the number of turns of the penetrating connection is not less than 3, one magnetic ring is used for driving energy input of signals, and an inductor of the magnetic ring and an external capacitor connected in parallel form an LC resonance circuit; the transmitting coil is driven by PWM waves, energy is coupled to the detecting coil through a through lead, the converter is connected in series in the CT detection secondary coil, different energy coupled to the detecting coil can be caused by different wiring modes of the CT detection secondary coil, currents generated by the detecting coil are also different, and the magnitude of the coupled currents can be measured through the sampling resistors connected in series on the sampling coil.
The scheme of the CT secondary side wiring state provided by the invention realizes the judgment of open circuit, short circuit, virtual short circuit and normal connection of the CT secondary side wiring by utilizing different CT secondary side wiring modes and different coupling energies of the detection coil and the sampling coil.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of a driving circuit according to the present invention;
FIG. 3 is a schematic diagram of a detection circuit according to the present invention;
FIG. 4 is a schematic diagram of a converter connection according to the present invention;
FIG. 5 is a software flow diagram of the present invention;
Detailed Description
The invention relates to a scheme for detecting the wiring state of the secondary side of a CT (computed tomography), which is characterized in that a converter is connected with the secondary side of a detected CT, the judgment of the open circuit, short circuit, virtual short and normal wiring state of the detected CT side is realized by driving the converter through a detection circuit and detecting the change of the voltage amplitude value of specific frequency output by the converter.
As shown in fig. 1, the schematic structural diagram of the scheme for detecting the secondary side connection state of the CT includes a detection circuit and a corresponding converter, wherein the converter is connected in series in the secondary side coil of the CT to be detected, and the converter isolates the signal generation circuit and the sampling circuit from the secondary side connection of the CT to be detected, thereby playing a role in protecting the back-end circuit. The converter is connected with the signal generating circuit and the signal sampling circuit, the signal generating circuit outputs PWM signals for driving the converter, signals coupled out through the converter are converted into digital signals through the sampling circuit by analog signals, the digital signals are transmitted to the data processing circuit, and the data processing circuit realizes the processing and judgment of data.
As shown in fig. 2, the driving circuit includes a resonant circuit composed of a coupling coil L and a capacitor C, a PWM generator provided in the detection chip drives the resonant circuit, the circuit continuously outputs a PWM signal with a specific frequency during the detection process, the driving converter continuously outputs a detection signal with a specific frequency, and the PWM signal is turned off after the state detection is completed.
As shown in fig. 3, the detection circuit includes a detection chip, an RC filter circuit, a detection coil of a converter, and a sampling resistor thereof, the drive coil continuously outputs a PWM signal with a specific frequency, and the drive coil is coupled to the detection coil through the converter, and after a high-frequency signal is filtered by the RC filter circuit, the detection chip can sample the specific frequency signal sent by the drive circuit and a power frequency signal for metering.
As shown in fig. 4, the converter includes 2 magnetic cores, one of which is a detection coil for inputting a PWM signal, and the other of which is a sampling coil for signal sampling, the two magnetic cores are connected through a lead wire, energy transmission is realized through the lead wire, the number of turns of the lead wire passing through the magnetic cores is not less than 3, and the more the number of turns, the more the detection accuracy can be improved.
As shown in fig. 5, after the processed digital signal is sampled, the data processing circuit is required to perform corresponding processing, and the data processing circuit is required to complete processing of the sampled signal and determine the specific working state of the secondary side of the CT through a series of processes. Firstly, if the sampling signal contains a power frequency signal, the external CT can be judged to be in a virtual short or normal connection state, then, whether the frequency amplitude of the sampling driving signal is in a normal power utilization interval or not is judged, if the sampling driving signal is in the normal power utilization interval, the sampling driving signal is judged to be in a normal connection state, and if the sampling driving signal is not in the normal power utilization interval, the sampling driving signal is judged to be in the virtual short connection state. If the sampling signal does not contain a power frequency signal, judging which section of short circuit, open circuit or normal connection the driving signal frequency amplitude is in, and further judging the wiring state of the external CT secondary side.
The embodiment of the invention can effectively detect the state of the secondary side wiring of the CT, provides a scheme for detecting the wiring state of the external CT by the metering equipment, and has the advantages of simple circuit and convenient expansion.
Claims (5)
1. A scheme for detecting the wiring state of the secondary side of a CT comprises a detection circuit and a corresponding converter, and is characterized in that: the detection circuit comprises a signal generation circuit, a signal sampling circuit and a data processing circuit; the converter comprises a signal sending part and a signal sampling part.
2. The CT secondary side wiring status scheme of claim 1 wherein: the detection circuit comprises an integrated PWM generator, an IC chip for 24-bit sigma-delta AD sampling and an MCU chip for data processing, wherein the PWM generator is used for signal transmission, the 24-bit sigma-delta AD is used for signal sampling and transmitting the sampled data to the MCU, and the MCU processes the sampled data.
3. The data processing circuit of claim 1, wherein: the data processing circuit receives the data provided by the signal sampling circuit, and performs corresponding mathematical operation to distinguish whether the amplitudes of different frequencies are available.
4. The converter of claim 1, wherein: the converter needs to be connected in series in a secondary coil on the CT side, the converter comprises 2 magnetic rings for winding enameled wires, the 2 magnetic rings are connected in a penetrating mode through conducting wires, the number of penetrating turns is larger than 3 and smaller than 7, a coil of one magnetic ring and a capacitor form an LC resonance circuit for sending detection signals, and the other magnetic ring is connected with a sampling resistor in parallel and connected to a signal sampling circuit for sampling signals.
5. The scheme for detecting the secondary side wiring state of the CT as claimed in claim 1, wherein: the signal generating circuit generates a signal of 1-3 kHz, the signal is transmitted to the sampling circuit through the converter, and the data processing circuit determines the working state of the secondary side wiring of the CT by judging the amplitude change of corresponding frequency points.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911322527.5A CN112285618A (en) | 2019-12-20 | 2019-12-20 | Scheme for detecting CT secondary side wiring state |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911322527.5A CN112285618A (en) | 2019-12-20 | 2019-12-20 | Scheme for detecting CT secondary side wiring state |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112285618A true CN112285618A (en) | 2021-01-29 |
Family
ID=74418875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911322527.5A Withdrawn CN112285618A (en) | 2019-12-20 | 2019-12-20 | Scheme for detecting CT secondary side wiring state |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112285618A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201251596Y (en) * | 2008-06-25 | 2009-06-03 | 三门利达电器有限公司 | Anti-theft electric pulse type precise current transformer combination |
| CN101666846A (en) * | 2009-09-25 | 2010-03-10 | 深圳市科陆电子科技股份有限公司 | System and method for detecting anomaly of secondary wiring of current mutual inductor |
| CN102411112A (en) * | 2011-08-02 | 2012-04-11 | 长沙威胜信息技术有限公司 | Method and circuit for detecting secondary side wiring state of primary metering CT (Computed Tomography) outside terminal |
| CN204028280U (en) * | 2014-06-26 | 2014-12-17 | 镇江瑞清电子科技有限公司 | A kind of secondary loop of mutual inductor failure detector |
| CN106645931A (en) * | 2016-11-29 | 2017-05-10 | 国网四川省电力公司电力科学研究院 | Current transformer secondary circuit monitoring module and method, and specific transformer acquiring terminal |
| CN107037303A (en) * | 2016-11-07 | 2017-08-11 | 北京博纳电气股份有限公司 | Detection means and detection method for tested CT secondary side circuit states outside ammeter |
-
2019
- 2019-12-20 CN CN201911322527.5A patent/CN112285618A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201251596Y (en) * | 2008-06-25 | 2009-06-03 | 三门利达电器有限公司 | Anti-theft electric pulse type precise current transformer combination |
| CN101666846A (en) * | 2009-09-25 | 2010-03-10 | 深圳市科陆电子科技股份有限公司 | System and method for detecting anomaly of secondary wiring of current mutual inductor |
| CN102411112A (en) * | 2011-08-02 | 2012-04-11 | 长沙威胜信息技术有限公司 | Method and circuit for detecting secondary side wiring state of primary metering CT (Computed Tomography) outside terminal |
| CN204028280U (en) * | 2014-06-26 | 2014-12-17 | 镇江瑞清电子科技有限公司 | A kind of secondary loop of mutual inductor failure detector |
| CN107037303A (en) * | 2016-11-07 | 2017-08-11 | 北京博纳电气股份有限公司 | Detection means and detection method for tested CT secondary side circuit states outside ammeter |
| CN106645931A (en) * | 2016-11-29 | 2017-05-10 | 国网四川省电力公司电力科学研究院 | Current transformer secondary circuit monitoring module and method, and specific transformer acquiring terminal |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| CN111650535B (en) * | 2020-05-29 | 2022-07-15 | 深圳供电局有限公司 | Electric energy meter wiring detection method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8593150B2 (en) | Method and apparatus for detecting a location of ground faults in a motor/motor drive combination | |
| CN102624325B (en) | Motor drive system, detection method of ground faults, and common mode choker system | |
| CN204679548U (en) | A kind of unicoil magnetic modulation type residual current detection device | |
| CN101937024A (en) | Capacitance measurement method and measurement device for power distribution network with neutral point grounded through arc suppression coil | |
| CN112285618A (en) | Scheme for detecting CT secondary side wiring state | |
| CN104166072B (en) | The intelligent device for detecting polarity of four star-like voltage transformers and detection method | |
| CN205092562U (en) | Residual current protection device | |
| CN105891606A (en) | Device for testing tower grounding resistance through disassembly-free ground lead | |
| CN101666846A (en) | System and method for detecting anomaly of secondary wiring of current mutual inductor | |
| CN205248099U (en) | After -current transformer | |
| CN104316825A (en) | Low voltage user electric energy meter wiring checking method and system | |
| CN104360223A (en) | System and method for detecting defects of micromotor rotor windings | |
| CN108427062B (en) | Frequency conversion resonance voltage-withstanding partial discharge test method adopting intermittent excitation | |
| CN207149352U (en) | Transformer demagnetization instrument with remanent magnetism quantitative analysis function | |
| CN103439072B (en) | A kind of electronic current mutual inductor soupling vibration test unit and method thereof | |
| CN114552584A (en) | Low-voltage power grid distribution area topology identification system and identification method | |
| CN112083231B (en) | Generator stator core loss test device capable of reducing closing impact current | |
| CN103743941A (en) | Wireless communication clamp alternating current ammeter without power supply | |
| CN104833929A (en) | Transformer demagnetization analyzer | |
| CN204347150U (en) | Responsive household electrical appliance harmonic wave immunity to interference test platform | |
| CN207281235U (en) | A kind of partial discharge intensity's detection circuit based on series process | |
| CN113358990B (en) | Oscillatory wave test system | |
| CN210669533U (en) | Resonance point debugging loop of high-voltage power filter device | |
| CN204556807U (en) | A kind of transformer demagnetization analyzer | |
| CN201373892Y (en) | Real-time detection circuit for preventing electricity-stealing in current method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20210129 |