CN2208709Y - Single chip microcomputer controlled ground fault positioning device - Google Patents

Single chip microcomputer controlled ground fault positioning device Download PDF

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Publication number
CN2208709Y
CN2208709Y CN 94242336 CN94242336U CN2208709Y CN 2208709 Y CN2208709 Y CN 2208709Y CN 94242336 CN94242336 CN 94242336 CN 94242336 U CN94242336 U CN 94242336U CN 2208709 Y CN2208709 Y CN 2208709Y
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CN
China
Prior art keywords
circuit
fault
low
insulation resistance
fault branch
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Expired - Fee Related
Application number
CN 94242336
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Chinese (zh)
Inventor
蔡旭
李冬辉
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China University of Mining and Technology CUMT
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China University of Mining and Technology CUMT
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Priority to CN 94242336 priority Critical patent/CN2208709Y/en
Application granted granted Critical
Publication of CN2208709Y publication Critical patent/CN2208709Y/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

A single chip microcomputer controlled ground fault positioning device belongs to the field of electrical protection. The device mainly comprises a micro-current sensor, a multi-way switch, an 8098 singlechip, a transmitter, a phase sensitive circuit, an analog-to-digital converter, a detector, an absolute value circuit, a low-frequency voltage sampling circuit, a synchronous signal forming circuit, a direct-current voltage sampling circuit, a shaping circuit, a low-frequency signal source, a function selection circuit, a display circuit, an alarm circuit, a level conversion circuit and the like. The utility model discloses can inquire insulation situation and the earth fault in each branch road of direct current system, can realize the automatic fault branch road of looking for, can detect earth fault's concrete position rapidly again.

Description

Single-board microcomputer controlled positioning device for grounding problems
The utility model relates to a kind of monolithic processor controlled DC system earth fault locating device that is used for, and belongs to the electrician who is used for generating plant, electric substation, factory's straight-flow system and protects monitoring device.
At present commonly used have bridge type insulation monitoring and warning device and a portable insulation monitoring and warning device.Its bridge type insulation monitoring and warning device can only be monitored the total dielectric level of bus, wants to find concrete fault branch, need carry out drawing dc feeder successively, and the power failure scope is big, and time-consuming, effort easily causes maloperation; Its portable insulation monitoring and warning device after bridge diagram sends alerting signal, installs by this that pincers can be to find out fault branch to every dc feeder successively; Cumbersome, also more time-consuming, the effort of this method operation.
The purpose of this utility model is to provide a kind of monolithic processor controlled device that is used for the DC system earth fault Search and Orientation, it can realize searching automatically fault branch, also can predict insulation status, can find out the particular location of fault again, overcome the deficiency of above two kinds of monitoring devices.
The utility model provides a kind of monolithic processor controlled earth fault positioning device.It is mainly formed circuit 10, DC voltage sample circuit 11, shaping circuit 12, low frequency signal source 13, function selector circuit 14, display circuit 15, warning circuit 16, level-conversion circuit 17 etc. and is formed by low current sensor 1, multi-way switch 2,8098 single-chip microcomputers 3, transmitter 4, phase-sensitive circuit 5, analog to digital converter 6, detecting device 7, absolute value circuit 8, low-frequency voltage sample circuit 9, synchronizing signal in Fig. 1 principle square frame.Wherein low current sensor 1 adopts the MXD-2000 magnetic material, and model is U 12, pay the limit and wind with 4000 circle coils, when primary side passed through the 100mA electric current, secondary side induced 40mV voltage; Multi-way switch 2 is selected the MC14051 chip, finishes the gating of 50 road current signals, adopts 7 MC14051 chips; Control signal is produced by 8098 single-chip microcomputers 3; Transmitter 4 selects that OP27 amplifies, filtering for use; Signal after the amplification enters phase-sensitive circuit 5, and phase-sensitive circuit 5 is made up of field effect transistor and transport and placing device; Its synchronizing signal comes from synchronizing signal and forms circuit 10, and phase sensitivity output is the resistive component of subcircuits, enters A/D afterwards to single-chip microcomputer 8098; Detecting device 7 adopts pincers shape list structure, when weak current 10mA flows through, makes light emitting diode bright through filtering, amplification etc., and buzzer sends the sound; Otherwise both all stop, and can discern the particular location of fault with this; Low frequency signal source 13 adopts two LF353 to form oscillator, and frequency is 36Hz, and its output is carried out power amplification through GF165, raises 6 times through transformer again, is added on the positive and negative busbar of straight-flow system by two capacitors; DC voltage sample circuit 11 adopts electric capacity and voltage follower to take out the voltage that is added in fault branch, the phase shift shaping that forms circuit 10 through synchronizing signal obtains exporting synchronous synchronizing signal with current sensor, and its output control phase-sensitive circuit 5 low-frequency voltage signal simultaneously enters A/D to single-chip microcomputer 3 through absolute value circuit 8.Level-conversion circuit 17 is finished the level conversion effect of warning circuit 16, display circuit 15, function selector circuit 14.Wherein display circuit adopts charactron to show, it drives and adopts MC1413, and decoding is finished by software.Single-chip microcomputer adopts high performance accurate 16 8098, and it has 10 A/D and reaches slewing rate faster, and arithmetic capability is stronger, and the computing of whole device and differentiation are finished by 8098, and its clock frequency is 12MHz.Insulation status and earth fault that the monolithic processor controlled fault locator that connects of the utility model can be inquired about straight-flow system each minute branch road automatically; Can detect the particular location of earth fault rapidly.During this device work, obtain U by DC voltage sample circuit and shaping circuit +, U -, U L, insulation resistance by formula calculates R +, R -:
R Σ=|U -0.5U|·R L/|U L|-R-2R L
R =U·R Σ/U
R =U·R Σ/U
The touring R that shows +, R -, U +, U -, U; When insulation resistance during less than 25k Ω, low frequency signal is put into electrical network, obtain being added in the ohmically voltage U i of fault branch by low-frequency voltage sample circuit and absolute value circuit, form circuit by low current sensor, multi-way switch, transmitter, phase-sensitive circuit and synchronizing signal again, obtain the current in resistance property Ii of fault branch,, Ui and Ii send into single-chip microcomputer 8098 through A/D, calculates insulation resistance R J: R J=Ui/Ii, relatively each branch road insulation resistance R JSize, find out fault branch, demonstrate fault branch number, insulation resistance, fault bus polarity, and report to the police.Simultaneously can be on fault branch with this Device Testing device pincers, by the direction motion of load, when buzzer from sound being arranged to nothing, when going out, this point is the concrete abort situation of fault branch just to light emitting diode from bright.And the utility model also adopts the multi-way switch selection mode, and a shared transmitter and phase-sensitive circuit carry out gating and differentiation by single-chip microcomputer 8098, and shared 10 A/D has improved the precision of system.The utility model also adopts R for improving discriminant accuracy JCalculating and Ui, Ii curve associating method of discrimination identification bus-bar fault by the rectangular area of Ui, an Ii is set, are eliminated the influence of disturbing.And the utlity model has long-time running, short-term operation, patrol apparent three kinds of working methods.
The utility model can directly be linked the positive and negative bus and the ground terminal of straight-flow system, puts a low current sensor on every feeder line simultaneously, and its access does not influence the running status of straight-flow system.And can inquire about the insulation status and the earth fault particular location of each minute branch road automatically, and numeral shows, reports to the police automatically, searches accurate, and the computational accuracy height is easy for installation, the reliability height.
Accompanying drawing 1 is a principle block diagram of the present utility model.
Accompanying drawing 2 is a profile synoptic diagram of the present utility model.
Accompanying drawing 3 is the utility model sample circuit schematic diagram.
Accompanying drawing 4 is the utility model transmission circuit schematic diagram.
Accompanying drawing 5 is the utility model low frequency signal schematic diagram.
In the accompanying drawing 2: 18 is that display, 19 is that positive bus-bar malfunction indicator lamp, 20 is that negative busbar malfunction indicator lamp, 21 is that power knob, 22 is that reset button, 24 is that linked network button, 25 is a casing for patrolling and examining button, 23.
With reference to the accompanying drawings embodiment of the present utility model is described in further detail below: at first make printed circuit board (PCB) according to circuit diagram, circuit board all adopts STD industrial bus standard.With multi-way switch 2, synchronizing signal forms circuit 10, low frequency signal source 13, display circuit 15, level-conversion circuit 17 is made a circuit board respectively, with 8098 single-chip microcomputers 3 and analog to digital converter 6, transmitter 4 and phase-sensitive circuit 5, absolute value circuit 8 and low-frequency voltage sample circuit 9, DC voltage sample circuit 11 and shaping circuit 12, function selector circuit 14 and warning circuit 16 are made a circuit board respectively, be welded on electronic devices and components in the circuit on the circuit board respectively, removing detecting device 7 is fixed in the pincerlike meter, display board is vertical be fixed on the panel of casing outside, on the machine cage of all vertical insertion of remaining circuit plate STD standard, be connected with flat cable by bus between each plate.The coil of low current sensor adopts winder around 4000 circles, is enclosed within on the U-iron core, and its lead-in wire is soldered on the terminals.The casing of this device adopts plastics or steel material punching press to make simultaneously.

Claims (1)

1, a kind of monolithic processor controlled earth fault positioning device mainly contains: low current sensor (1), multi-way switch (2), 8098 single-chip microcomputers (3), transmitter (4), phase-sensitive circuit (5), analog to digital converter (6), detecting device (7), absolute value circuit (8), low-frequency voltage sample circuit (9), synchronizing signal form circuit (10), DC voltage sample circuit (11), shaping circuit (12), low frequency signal source (13), function selector circuit (14), display circuit (15), warning circuit (16), level-conversion circuit compositions such as (17); Components and parts in the circuit are welded on respectively on a plurality of circuit boards, removing detecting device (7) is fixed in the pincerlike meter, display board is vertical be fixed on the panel of casing outside, on the machine cage of all vertical insertion of remaining circuit plate STD standard, be connected with flat cable by motherboard between each plate; During this device operate as normal, it is characterized in that: obtain U by DC voltage sample circuit and shaping circuit +, U -, U L, insulation resistance by formula calculates R +, R -:
R Σ=(|U +-0.5U|·R L/|U L|)-R-2R L
R +=U/U -·R Σ
R -=U/U +·R Σ
The touring R that shows +, R -, U +, U -, U; When insulation resistance during less than 25K Ω, low frequency signal is put into electrical network, obtain being added in the ohmically voltage U of fault branch by low-frequency voltage sample circuit and absolute value circuit i, form circuit by low current sensor, multi-way switch, transmitter, phase-sensitive circuit and synchronizing signal again, obtain the current in resistance property I of fault branch i, U iAnd I iSend into single-chip microcomputer 8098 through A/D, calculate insulation resistance R J: R J=U i/ I i, compare each branch road insulation resistance R then JSize, find out fault branch, demonstrate fault branch number, insulation resistance, fault bus polarity, and report to the police; This moment can be with the detecting device pincers on fault branch, by the direction motion of load, when buzzer from sound being arranged to nothing, when going out, this point is the concrete abort situation of fault branch just to light emitting diode from bright.
CN 94242336 1994-07-26 1994-07-26 Single chip microcomputer controlled ground fault positioning device Expired - Fee Related CN2208709Y (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 94242336 CN2208709Y (en) 1994-07-26 1994-07-26 Single chip microcomputer controlled ground fault positioning device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 94242336 CN2208709Y (en) 1994-07-26 1994-07-26 Single chip microcomputer controlled ground fault positioning device

Publications (1)

Publication Number Publication Date
CN2208709Y true CN2208709Y (en) 1995-09-27

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN 94242336 Expired - Fee Related CN2208709Y (en) 1994-07-26 1994-07-26 Single chip microcomputer controlled ground fault positioning device

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CN (1) CN2208709Y (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100374871C (en) * 2005-06-28 2008-03-12 天津大学 Detecting device and its method for DC system earthing fault
CN100385764C (en) * 2005-01-31 2008-04-30 张玉民 Earth leakage protecting method and apparatus for one line one ground type DC supply circuit
CN1939043B (en) * 2004-03-30 2010-12-15 英国电讯有限公司 Electrical wire joint fault detection
CN101452034B (en) * 2007-11-30 2011-08-10 上海市电力公司 Portable intelligent DC earthing searching instrument
CN101750540B (en) * 2009-12-25 2011-11-02 上海希明电气技术有限公司 Method for detecting parasitic loop of transformer station direct current system
CN104849676A (en) * 2015-01-12 2015-08-19 国家电网公司 DC insulation monitoring device for signal injection method
CN108076658A (en) * 2015-06-15 2018-05-25 雷诺有限合伙公司 Electrical system including the circuit for being used to detect electrical isolation failure

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1939043B (en) * 2004-03-30 2010-12-15 英国电讯有限公司 Electrical wire joint fault detection
CN100385764C (en) * 2005-01-31 2008-04-30 张玉民 Earth leakage protecting method and apparatus for one line one ground type DC supply circuit
CN100374871C (en) * 2005-06-28 2008-03-12 天津大学 Detecting device and its method for DC system earthing fault
CN101452034B (en) * 2007-11-30 2011-08-10 上海市电力公司 Portable intelligent DC earthing searching instrument
CN101750540B (en) * 2009-12-25 2011-11-02 上海希明电气技术有限公司 Method for detecting parasitic loop of transformer station direct current system
CN104849676A (en) * 2015-01-12 2015-08-19 国家电网公司 DC insulation monitoring device for signal injection method
CN108076658A (en) * 2015-06-15 2018-05-25 雷诺有限合伙公司 Electrical system including the circuit for being used to detect electrical isolation failure
CN108076658B (en) * 2015-06-15 2020-08-21 雷诺有限合伙公司 Electrical system comprising an electrical circuit for detecting an electrical insulation fault

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C19 Lapse of patent right due to non-payment of the annual fee
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