CN103956714A - High-sensitivity multifunctional CT open circuit protection device - Google Patents
High-sensitivity multifunctional CT open circuit protection device Download PDFInfo
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- CN103956714A CN103956714A CN201410168046.4A CN201410168046A CN103956714A CN 103956714 A CN103956714 A CN 103956714A CN 201410168046 A CN201410168046 A CN 201410168046A CN 103956714 A CN103956714 A CN 103956714A
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Abstract
The invention relates to the field of protection devices of electric power circuits, equipment and the like, in particular to a high-sensitivity multifunctional CT open circuit protection device which is characterized in that a signal sampling part, an executing protecting part, a single chip microcomputer, a liquid crystal displaying part and a fault resetting part are included, the CT protection device has a basic fault displaying function, a total fault frequency recording function and a fault moment voltage value and voltage waveform displaying and recording function, a foundation is provided for working personnel to check whether a device connected with a secondary side of a current transformer can cause unrecoverable damage due to secondary side open circuit voltage, fault checking of whole equipment provided with the current transformer is convenient, and maintaining time and labor cost are saved.
Description
Technical field:
The present invention relates to the protective device fields such as power circuit, equipment, specifically the multi-functional CT open-circuit protecting device of a kind of high sensitivity.
Background technology:
The safe operation of power circuit, closely bound up with the construction of national economy and personnel's safety.Current transformer is to provide a kind of facility that can reflect the corresponding current parameters of system for detecting instrument and control device, and the safe operation of electric power system is very important, operation rule regulation: in service, Current Transmit secondary side circuit can not be opened a way.The open circuit once Current Transformer Secondary winding and loop thereof are in operation, will produce the overvoltage of thousands of volts volts even up to ten thousand.This works the mischief not only to the insulation of electrical secondary system, also can make the too drastic and scaling loss of instrument transformer, the life security that even jeopardizes operations staff.
For these problems, many technical work personnel work it out many contributions, for example: application number 89216913.3, notification number CN2074493U, denomination of invention: Installation of Open-circuit Protection for Current Transformers; Application number 00229882.1, notification number CN2602931Y, denomination of invention: silicon controlled open circuit protector for electric power current transformer; Application number 200420010869.6, notification number CN2715407Y, denomination of invention: CT open circuit protector with high sensitivity etc., although some protective devices are obtained certain effect after coming into operation at present, protective device still has problems:
The fault detection part of existing Installation of Open-circuit Protection for Current Transformers is used pure hardware detecting circuit; select optocoupler to judge device as fault; being input to single-chip microcomputer or other protection action triggers circuit is low and high level signal; cannot be when current transformer be opened a way record trouble voltage and false voltage waveform constantly; thereby cannot cause expendable damage by the failure judgement possibility pair device relevant to instrument transformer, be unfavorable for being equipped with the malfunction elimination of current transformer complete equipment.
Summary of the invention:
In order to overcome above-mentioned the deficiencies in the prior art, the present invention designs the multi-functional CT open-circuit protecting device of a kind of high sensitivity.This programme is intended to solve the problem that prior art cannot be monitored instrument transformer open circuit voltage and be preserved fault moment waveform.
The technical problem solving adopts following technical scheme:
The multi-functional CT open-circuit protecting device of high sensitivity, is characterized in that: contain signal sampling part, carry out protection part, single-chip microcomputer and liquid-crystal display section and failure reset part;
Described signal sampling is partly: input voltage, through two divider resistances, is connected with Order RC filter; TVS pipe of a parallel connection in divider resistance; Order RC filter is connected with signal input amplifier, by the voltage of raising accessing in signal amplifier circuit, sampling input voltage is raised, and realizes the sampling to AC signal; The output of signal input amplifier is connected with the AD sampling pin of single-chip microcomputer through protective circuit of diode;
Described execution protection part is: driving power is connected with the input anode of optical coupling isolator through the first resistance; Single-chip microcomputer delivery outlet connects the input negative terminal of optical coupling isolator; Optical coupling isolator output one end the second resistance connects the gate leve of bidirectional triode thyristor, another termination bidirectional triode thyristor; Two pins beyond the gate leve of bidirectional triode thyristor connect respectively input and common port;
Described liquid-crystal display section: the AD sampling functions of single-chip microcomputer and the programming of single-chip microcomputer realize, and LCD LCDs is selected in display section, and displaying contents has: 20ms voltage waveform and total failare number of times before fault phase, fault moment magnitude of voltage, fault moment.
Described failure reset is partly: one group of power supply comprises VCC, GND, and second group of power supply comprises VCC1, GNDA, and VCC, GND are directly connected by common mode inductance with VCC1, two groups of power supplys of GNDA, and VCC1 is connected with capacitance cathode, and GND is connected with electric capacity negative pole; Capacitance cathode is connected with bipod and interface of external reset of reset key through the 3rd resistance; The another bipod of reset key and another interface of external reset are connected with the positive pole of optocoupler input; The negative pole of electric capacity is connected with the negative pole of optocoupler input; Optocoupler output collector electrode connects the input port of single-chip microcomputer, meets power supply VCC through pull-up resistor simultaneously; Optocoupler output emitter connects GND end.
Described signal input signal amplifier circuit comprises amplifier, be connected to the resistance R 6 on amplifier negative pole, be connected to the resistance R 7 of amplifier negative pole and amplifier out, and be connected to the resistance R 8 on amplifier anode, the negative pole of described amplifier is connected with the resistance output of Order RC filter, and described resistance R 8 is connected with the electric capacity output of Order RC filter with the other end of amplifier.
The invention has the beneficial effects as follows:
(1) the present invention input port of sampling adopts connect with the small resistor principle of dividing potential drop of a large resistance, and resistance value is very large, has effectively reduced CT secondary side and has shunted;
(2) protective device voltage sample of the present invention is accurate, highly sensitive;
(3) protective device antijamming capability of the present invention is strong, and system power supply is partly used integrated AC-DC modular power, and system is more stable;
(4) CT open-circuit protecting device of the present invention is adaptable for multiloop protective device, can be according to CT secondary winding quantity arbitrary extension;
(5) the present invention has 485 communication functions, has installed signal transmission interface additional, can realize and the networking of comprehensive automation control appliance, has greatly increased automaticity;
(6) CT protective device of the present invention is except basic fault Presentation Function and total failare number of times writing function; with fault moment magnitude of voltage and voltage waveform, show and writing function; whether the device being connected with Current Transformer Secondary side for staff's investigation can cause expendable damage that foundation is provided because of secondary side open circuit voltage; facilitate the malfunction elimination that is equipped with the complete equipment of current transformer, saved repair time and human cost.
Accompanying drawing explanation:
Fig. 1 is structural representation of the present invention.
Embodiment:
For technological means, creation characteristic that the present invention is realized, reach object and effect is easy to understand, below in conjunction with concrete diagram, further set forth the present invention.
As shown in Figure 1,
The multi-functional CT open-circuit protecting device of high sensitivity, contains signal sampling part, carries out protection part, single-chip microcomputer and liquid-crystal display section and failure reset part;
Signal sampling is partly: input voltage is through two divider resistance R1 and R2, and input voltage, through divider resistance R1 and R2, is connected with Order RC filter; The upper TVS pipe in parallel of divider resistance R2, protection sample circuit; Order RC filter is connected with signal amplifier circuit, by what access in signal amplifier circuit, raises voltage VRef, and sampling input voltage is raised, and realizes the sampling to AC signal; The output of signal input signal amplifier circuit is connected with Chip Microcomputer A/D sampling pin through protective circuit of diode.
Secondary winding input voltage is after R1 and R2 dividing potential drop; voltage on R2 carries out filtering through Order RC filter circuit; again through signal amplifier circuit voltage by integral raising; raising voltage magnitude is VRef; signal amplifier circuit output is after diode clamp protective circuit; be input to Chip Microcomputer A/D thief hatch, by mcu programming, calculate the input voltage value of secondary winding reality.Principle and the method calculated are as follows: the input voltage of the input of protector is V
iN, VRef has guaranteed at V more than the alternating voltage of input is raised to zero volt
iNduring for negative value, single-chip microcomputer still can normally carry out AD conversion work.The magnitude of voltage that is input to Chip Microcomputer A/D thief hatch is
the pass of deriving thus the voltage of Current Transformer Secondary side virtual voltage and Chip Microcomputer A/D mouth is
Carrying out protection part is: driving power VCC is connected with the input anode of optical coupling isolator through the first resistance 1R; Single-chip microcomputer delivery outlet connects the input negative terminal of optical coupling isolator; Optical coupling isolator output one end the second resistance 2R connects the gate leve of bidirectional triode thyristor BT136, another termination bidirectional triode thyristor BT136; Two pins beyond the gate leve of bidirectional triode thyristor BT136 connect respectively input and common port.
When CT normally works; secondary winding input voltage is lower; single-chip microcomputer sampling calculates secondary winding input voltage value and is less than startup value; single-chip microcomputer delivery outlet in drive circuit is output as high level; triode ac switch in optical coupling isolator cannot conducting; the bidirectional triode thyristor gate leve of CT short circuit effect, without driving signal, is not protected action.When CT open circuit; secondary winding input voltage is very large; single-chip microcomputer sampling calculates secondary winding input voltage value and is greater than startup value; single-chip microcomputer delivery outlet in drive circuit is output as low level; triode ac switch conducting in optical coupling isolator; the bidirectional triode thyristor gate leve signal that drives CT short circuit effect, bidirectional triode thyristor is protected action.
Liquid-crystal display section: the AD sampling functions of single-chip microcomputer and the programming of single-chip microcomputer realize, LCD LCDs is selected in display section, and displaying contents has: 20ms voltage waveform (comprising fault moment) and total failare number of times before fault phase, fault moment magnitude of voltage, fault moment.
Failure reset is partly: one group of power supply comprises VCC, GND, and second group of power supply comprises VCC1, GNDA, and in Fig. 1, VCC, GND are directly connected by common mode inductance with VCC1, two groups of power supplys of GNDA.VCC1 is connected with capacitance cathode, and GND is connected with electric capacity negative pole; Capacitance cathode is connected with 1,3 pin of reset key SW and 5 pin of external reset interface through resistance SW_R1; 2,4 pin of reset key SW and 6 pin of external reset interface are connected with the positive pole of optocoupler input; The negative pole of electric capacity is connected with the negative pole of optocoupler input; Optocoupler output collector electrode connects the input port of single-chip microcomputer, meets power supply VCC through pull-up resistor SW_R2 simultaneously; Optocoupler output emitter connects GND end.
External reset interface is not when off-state and reset key are pressed, and optocoupler input anode is unsettled, and optocoupler is not worked, and its output is equivalent to off state, single-chip microcomputer input port input high level; When external reset interface is when short circuit state or reset key are pressed, optocoupler work, output is equivalent to path, single-chip microcomputer input port input low level.Single-chip microcomputer judges that this pin becomes low level from high level, and the state of inner each quantity of state that resets is to init state, and faulty indication etc. are eliminated.
Signal input signal amplifier circuit comprises amplifier, be connected to the resistance R 6 on amplifier negative pole, be connected to the resistance R 7 of amplifier negative pole and amplifier out, and be connected to the resistance R 8 on amplifier anode, the negative pole of amplifier is connected with the resistance output of Order RC filter, and resistance R 8 is connected with the other end of amplifier and the electric capacity output of Order RC filter.
More than show and described basic principle of the present invention and principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; that in above-described embodiment and specification, describes just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.The claimed scope of the present invention is defined by appending claims and equivalent thereof.
Claims (3)
1. the multi-functional CT open-circuit protecting device of high sensitivity, is characterized in that: contain signal sampling part, carry out protection part, single-chip microcomputer and liquid-crystal display section and failure reset part;
Described signal sampling part: input voltage, through two divider resistances, is connected with Order RC filter; TVS pipe of a parallel connection in divider resistance; Order RC filter is connected with signal input signal amplifier circuit, by the voltage of raising accessing in signal amplifier circuit, sampling input voltage is raised, and realizes the sampling to AC signal; Signal amplifier circuit output is connected with the AD sampling pin of single-chip microcomputer through protective circuit of diode;
Described execution protection part is: driving power is connected with the input anode of optical coupling isolator through the first resistance; Single-chip microcomputer delivery outlet connects the input negative terminal of optical coupling isolator; Optical coupling isolator output one end the second resistance connects the gate leve of bidirectional triode thyristor, another termination bidirectional triode thyristor; Two pins beyond the gate leve of bidirectional triode thyristor connect respectively input and common port;
Described liquid-crystal display section: the AD sampling functions of single-chip microcomputer and the programming of single-chip microcomputer realize, and LCD LCDs is selected in display section, and displaying contents has: 20ms voltage waveform and total failare number of times before fault phase, fault moment magnitude of voltage, fault moment.
2. the multi-functional CT open-circuit protecting device of a kind of high sensitivity according to claim 1, it is characterized in that: described failure reset is partly: one group of power supply comprises VCC, GND, second group of power supply comprises VCC1, GNDA, VCC, GND are directly connected by common mode inductance with VCC1, two groups of power supplys of GNDA, VCC1 is connected with capacitance cathode, and GND is connected with electric capacity negative pole; Capacitance cathode is connected with bipod and interface of external reset of reset key through the 3rd resistance; The another bipod of reset key and another interface of external reset are connected with the positive pole of optocoupler input; The negative pole of electric capacity is connected with the negative pole of optocoupler input; Optocoupler output collector electrode connects the input port of single-chip microcomputer, meets power supply VCC through pull-up resistor simultaneously; Optocoupler output emitter connects GND end.
3. the multi-functional CT open-circuit protecting device of a kind of high sensitivity according to claim 1; it is characterized in that: described signal input signal amplifier circuit comprises amplifier; be connected to the resistance R 6 on amplifier negative pole; be connected to the resistance R 7 of amplifier negative pole and amplifier out; and be connected to the resistance R 8 on amplifier anode; the negative pole of described amplifier is connected with the resistance output of Order RC filter, and described resistance R 8 is connected with the electric capacity output of Order RC filter with the other end of amplifier.
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| CN201410168046.4A CN103956714B (en) | 2014-04-24 | 2014-04-24 | A kind of high sensitivity multi-functional CT open-circuit protecting device |
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| CN201410168046.4A CN103956714B (en) | 2014-04-24 | 2014-04-24 | A kind of high sensitivity multi-functional CT open-circuit protecting device |
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| CN103956714B CN103956714B (en) | 2016-09-07 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105449655A (en) * | 2014-09-03 | 2016-03-30 | 国网河南省电力公司平顶山供电公司 | Current transformer secondary open circuit protection method and device |
| CN106532640A (en) * | 2016-10-26 | 2017-03-22 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protection device of current transformer |
| CN108418433A (en) * | 2018-03-29 | 2018-08-17 | 深圳驿普乐氏科技有限公司 | A kind of LLC resonant converter and its control circuit, resonance current sample circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105449655A (en) * | 2014-09-03 | 2016-03-30 | 国网河南省电力公司平顶山供电公司 | Current transformer secondary open circuit protection method and device |
| CN105449655B (en) * | 2014-09-03 | 2018-05-22 | 国网河南省电力公司平顶山供电公司 | A kind of Current Transformer Secondary open-circuit-protection method and device |
| CN106532640A (en) * | 2016-10-26 | 2017-03-22 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protection device of current transformer |
| CN106532640B (en) * | 2016-10-26 | 2018-11-27 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protecting equipment of current mutual inductor |
| CN108418433A (en) * | 2018-03-29 | 2018-08-17 | 深圳驿普乐氏科技有限公司 | A kind of LLC resonant converter and its control circuit, resonance current sample circuit |
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| Publication number | Publication date |
|---|---|
| CN103956714B (en) | 2016-09-07 |
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Effective date of registration: 20170524 Address after: 201, room 3, building 16, 230000 Ning Xi Road, Hefei hi tech Zone, Anhui Patentee after: Anhui wohua Electric Equipment Co., Ltd. Address before: 230031, No. 21 Hangzhou Road, Hefei hi tech Zone, Anhui Patentee before: HEFEI VOVA ELECTRICAL TECHNOLOGY CO., LTD. |
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