CN2890943Y - Portable direct current system earthing fault detector - Google Patents
Portable direct current system earthing fault detector Download PDFInfo
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- CN2890943Y CN2890943Y CN 200520019966 CN200520019966U CN2890943Y CN 2890943 Y CN2890943 Y CN 2890943Y CN 200520019966 CN200520019966 CN 200520019966 CN 200520019966 U CN200520019966 U CN 200520019966U CN 2890943 Y CN2890943 Y CN 2890943Y
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Abstract
The utility model discloses a portable direct current grounding fault detector, which comprises a current clamp, a signal processing circuit, an A/D transformer, a single-chip machine, a liquid crystal display, a chargeable power supply, a transformation circuit, and a low frequency signal source, wherein the signal processing circuit comprises a resistance measuring circuit and a capacitance measuring circuit. The device can measure branch circuthe of grounding the direct current system and can confirm grounding fault points through transforming the current clamp measuring points, the instrument automatically displays the grounding capacitance value and grounding resistance value of the measuring circuit and can effectively check the states of capacitance and resistance distribution of each circuit of the direct current system. The detector adopts a portable and small power consumption design to meet the fault positioning and searching needs of electrical examining and repairing.
Description
Affiliated technical field
The utility model relates to the earth fault location of straight-flow system in the power industry and searches measurement, and it is bigger to be specially adapted to straight-flow system power, duplexure complexity, generating plant, transformer station direct current system grounding fault that distribution area is wider.
Background technology
At present, China's power industry has successfully been installed various forms of online DC earthing line selection apparatus and insulating monitoring relay in straight-flow system.Along with the continuous increase of net capacity, the improving constantly of electric pressure, straight-flow system also becomes increasingly complex along with the increase in power station, and duplexure is also more various.Simultaneously in a single day ground connection take place in straight-flow system, and the normal operation of power network has been constituted serious potential safety hazard, clearly is defined in eight hours in the relevant electric power rules and removes.Which loop ground connection existing ground connection detector can only indicate, can not be effectively give accurate location to the loop fault point that ground connection is taken place, direct earth capacitance value that simultaneously can't the measurement branches loop.Be that most measuring equipment all is that genus is fixed, can't realize moving.It is the duplexure that generation ground connection is taken place a bit and can only be known during multipoint earthing for the straight-flow system of transformer station and generating plant, can't further position fixed point inspection with instrumentation, the earth point of fixing a breakdown is lacked corresponding mobile equipment, determine simultaneously and get rid of and still select traditional power failure means of operating a switch when breaking down ground connection.Along with improving constantly of power automation level, a large amount of utilizations of computing machine, existing ground connection detecting instrument can't satisfy the requirement that power failure is searched maintenance.
Summary of the invention
The purpose of this utility model is: a kind of Portable DC system earth malfunction detector that can move at any time is provided, adopt mobile, little power consumption design, can satisfy electric power overhaul better, search position determination of fault, location, better, fix a breakdown quickly, successfully solve existing fixed pick-up unit, the further drawback of the localization of faults.
The utility model purpose is achieved in that whole device by current clamp 1, signal processing circuit 2, and A/D converter 3, single-chip microcomputer 4, LCD 5, rechargable power supplies and translation circuit 6, low frequency signal source 7 is formed.Its circuit is connected to the output terminal of low frequency signal source 7 and the plus or minus end of straight-flow system bus joins, and signal seedbed and the earth join; The output terminal of rechargable power supplies and translation circuit 6 respectively with the circuit power end mutually and connect; Current clamp 1 and signal processing circuit 2 input ends join; Signal processing circuit 2 output terminals and A/D converter 3 input ends join, and A/D converter 3 output terminals are connected with single-chip microcomputer 4, and the output terminal of single-chip microcomputer 4 and display circuit 5 join.
Also be to comprise resistance measurement loop, capacitance measurement loop, multidiameter option switch composition according to right 1. described signal processor 2 its features.Wherein the resistance measurement loop is made up of signal amplification circuit D1, D2 phase-shift circuit D3, rectification circuit D4 respectively; The capacitance measurement loop is made up of signal transformation circuit D5, D6 and absolute value circuit D7, D8 and multidiameter option switch D9.Its circuit is connected to the output terminal of signal amplification circuit D1 and the input end of D2 joins, and the output terminal of D2 and phase-shift circuit D3 join, and phase-shift circuit D3 output terminal and rectification circuit D4 join, and rectification circuit D4 output terminal and multidiameter option switch D9 input end join; The output terminal of signal transformation circuit D5 and shaping circuit D6 input end join, the output terminal of shaping circuit D6 and absolute value circuit D7 join, absolute value circuit D7 output terminal and absolute value circuit input end D8 join, and the output terminal of absolute value circuit D8 and multidiameter option switch D9 input end join.
The utility model and in the past the significant difference place was arranged at wire mounting monitoring device and other survey instruments, and on engineering, use following advantage is arranged.
1. device can be measured outside the grounding resistance of direct current branch loop automatically, can also measurement branches loop direct earth capacitance value.
2. device can be determined the earth fault origination point at any time according to in-site measurement demand traverse measurement point.
3. searching the trouble spot is live line measurement, and measurement need not have a power failure.
4. device is that little power consumption is carried out, and belongs to the rechargable power supplies power supply, need not add any power source, and is easy to use, safe.
Description of drawings
Described in detail below in conjunction with relevant drawing
Fig. 1. the theory diagram of entire measuring device.
Fig. 2. utility model embodiment signal processing circuit detail drawing.
Block diagram 1. whole devices are by current clamp 1, signal processing circuit 2, and A/D converter 3, single-chip microcomputer 4, LCD 5, rechargable power supplies and translation circuit 6, low frequency signal source 7 is formed.
Fig. 2, signal processing circuit is by formations such as D1, D2, D3, D4, D5, D6, D7, D8, D9; Wherein the resistance measurement loop is made of D1, D2, D3, D4, and the capacitance measurement loop is made of D5, D6, D7, D8, and multidiameter option switch is made up of D9.
Embodiment
As shown in Figure 1, its circuit is connected to the output terminal of low frequency signal source 7 and the plus or minus end of straight-flow system bus joins, and signal seedbed and the earth join, the output terminal of rechargable power supplies and translation circuit 6 respectively with the circuit power end mutually and connect; Current clamp 1 and signal processing circuit 2 input ends join; Signal processing circuit 2 output terminals and A/D converter 3 input ends join, and the A/D converter output terminal is connected with single-chip microcomputer 4, and the output terminal of single-chip microcomputer 4 and display circuit 5 join.The measured electric current alternating signal of current clamp carries out the A/D conversion through delivering to the A/D change-over circuit after the processing of treatment circuit, single-chip microcomputer carries out computational analysis according to the signal of measuring, the conversion of measured current signal value be converted to grounding resistance and and the predefined stake resistance thresholding of instrument compare, instrument sends sound and light alarm during less than the alarm threshold value as resistance value, and single-chip microcomputer shows stake resistance information simultaneously by LCD.Rechargable power supplies adopts high efficiency chargeable storage, and cell voltage is 6V, and power converting circuit is the power source conversion one-tenth+5V of 6V ,-5V, and+12V, voltages such as-12V are given each element circuit.Low frequency signal source adopts the output of AT89C2051 single-chip microcomputer to be fed on the straight-flow system by the R-C coupling method through the sine wave signal (peak value is 10V) that D/A converter (DA0832) produces 2HZ, can measurement of Grounding Resistance value and capacitance by direct supply so measure no matter whether the loop have.Wherein current clamp adopts the Ksp current clamp that Henan spark technology research institute produces, and this device can adopt two kinds of opening forms, if the ground loop electric current is bigger, electric wire more slightly adopts the bigger current clamp of opening, and opening size is Φ 28; Thinner employing opening less current pincers, opening size is Φ 28; Two kinds of current clamps can exchange.A/D converter adopts AD7543,12 A/D converters; Single-chip microcomputer adopts the 78E52B single-chip microcomputer of Taiwan Winbond company production or the AT89C55 that AT company produces, and the model that LCD adopts Beijing high official position Creative Technology Ltd. to produce is Lcm045 eight number section liquid crystal.The shell of device can adopt the potable metal tool housing to have waterproof, the special characteristics of anti-electromagnetic interference (EMI).
The detailed description of block diagram 2. expression utility model embodiment signal processing circuits, its feature also is to comprise resistance measurement loop, capacitance measurement loop, multidiameter option switch composition, and wherein the resistance measurement loop is made up of signal amplification circuit D1, D2, phase-shift circuit D3, rectification circuit D4 respectively; The capacitance measurement loop is made up of signal transformation circuit D5, D6 and absolute value circuit D7, D8 and multidiameter option switch D9.Circuit is connected to the output terminal of signal amplification circuit D1 and the input end of D2 joins, and the output terminal of D2 and phase-shift circuit D3 join, and phase-shift circuit D3 output terminal and rectification circuit D4 join, and rectification circuit D4 output terminal and multidiameter option switch C input end join; The output terminal of signal transformation circuit D5 and shaping circuit D6 input end join, the output terminal of shaping circuit D6 and absolute value circuit D7 join, absolute value circuit D7 output terminal and absolute value circuit input end D8 join, and the output terminal of absolute value circuit D8 and multidiameter option switch D9 input end join.The electric current alternating signal that current clamp samples is delivered to the D1 amplification by R1 and is delivered to D2 and D5 through capacitor C 3 and C11 respectively after the C1 decoupling.D2 carries out signal with the signal after amplifying through D1 to amplify once more.D2 amplifies signal after the coupling of electric C5 reaches D3, D3 and resistance R 8, W1, R10, C6, C7 constitute the signal phase-shift circuit, electric capacity and current signal are through distinguishing capacitance current and resistor current (electric capacity phase place leading current phase place 90 degree) behind the phase-shift circuit, deliver to D4 through R9 and do signal rectification, signal rectifier circuit is made of R11, R12, R13, R14, C9, C10, D4 etc., and D1, D2, D3, D4 adopt LF412 dual power supply operational amplifier.So because capacitance signal obtains intact sinusoidal signal greater than resistance signal capacitance measurement loop through behind the signal transformation circuit of D5, D6, wherein shaping circuit is made up of R14.C13, R15, R16, D5 and C14, R17, C15, C16, R18, R19, D6.Signal shaping is after C17 delivers to D7, D8 carries out signal and do absolute value and handle, its circuit respectively by: R20, R21, R22, R23, R24, S1, S2, D7 and R25, R26, R27, C1, D8 form.The measuring-signal in circuit measuring loop and capacitance measurement loop delivers to A/D converter after the multichannel of multidiameter option switch is selected and single chip circuit calculates comparison.The current clamp signal measurement is fed on the straight-flow system to low frequency signal source, flow through the electric current alternating signal of stake resistance or direct earth capacitance, handle differentiation capacitance current and resistor current through signal processing circuit, single-chip microcomputer is judged calculating grounding resistance and capacitance according to the capacitance current of ground loop and the size of resistor current value respectively, and show that by LCD the user promptly knows the grounding resistance and the capacitance in this loop.Current clamp can mobile at any time measured point, if having, the current clamp measurement point measures the current signal that flows through stake resistance, the expression earth point is in current clamp measurement point back, on ground loop, measure one by one, if measurement point disappears on tested ground loop, the expression earth point is just before the quilt test point that disappears.Just can utilize two place's measurement points to determine that earth point just occurs in ground signalling and do not have between 2 of ground signalling in the test process.This device also can remove to measure each duplexure in the straight-flow system that ground connection is taken place simultaneously, searches ground loop.Utilize this measurement device to carry out under the power down mode not needing, instrument adopts the rechargeable battery power supply, and the circuit of employing and electronic component are little power consumption design, battery once charges and can use more than 10 hours, instrument is easy to use, and is safe and reliable, stable performance.
Claims (2)
1, a kind of Portable DC system earth malfunction detector is by current clamp (1), signal processing circuit (2), and A/D converter (3), single-chip microcomputer (4), LCD (5), rechargable power supplies and translation circuit (6), low frequency signal source (7) is formed; Its circuit is connected to the output terminal of low frequency signal source (7) and the plus or minus end of straight-flow system bus joins, signal seedbed and the earth join, the output terminal of rechargable power supplies and translation circuit 6 respectively with the circuit power end mutually and connect, current clamp (1) and signal processing circuit (2) input end join; Signal processing circuit (2) output terminal and A/D converter (3) input end join, and A/D converter (3) output terminal is connected with single-chip microcomputer (4), and the output terminal of single-chip microcomputer (4) and display circuit (5) join.
2, according to right 1 described Portable DC system earth malfunction detector, its feature also is: described signal processing circuit (2) comprises resistance measurement loop, capacitance measurement loop, multidiameter option switch composition; Wherein the resistance measurement loop is made up of signal amplification circuit (D1, D2), phase-shift circuit (D3), rectification circuit (D4) respectively; The capacitance measurement loop is made up of signal transformation circuit (D5, D6) and absolute value circuit (D7, D8) and multidiameter option switch (D9).Its circuit is connected to the output terminal of signal amplification circuit (D1) and input end (D2) joins, (D2) output terminal and phase-shift circuit (D3) join, phase-shift circuit (D3) output terminal and rectification circuit (D4) join, and rectification circuit (D4) output terminal and multidiameter option switch (D9) input end join; The output terminal of signal transformation circuit (D5) and shaping circuit (D6) input end join, the output terminal and the absolute value circuit D7 of shaping circuit (D6) join, absolute value circuit (D7) output terminal and insulator chain input end (D8) join, and the output terminal of absolute value circuit (D8) and multidiameter option switch (D9) input end join.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520019966 CN2890943Y (en) | 2005-05-09 | 2005-05-09 | Portable direct current system earthing fault detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520019966 CN2890943Y (en) | 2005-05-09 | 2005-05-09 | Portable direct current system earthing fault detector |
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| Publication Number | Publication Date |
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| CN2890943Y true CN2890943Y (en) | 2007-04-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 200520019966 Expired - Fee Related CN2890943Y (en) | 2005-05-09 | 2005-05-09 | Portable direct current system earthing fault detector |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101995518A (en) * | 2009-08-11 | 2011-03-30 | 中国铝业股份有限公司 | Aluminium electrolysis bus system resistance to ground detection device and detection method thereof |
| CN102879682A (en) * | 2012-09-26 | 2013-01-16 | 国家电网公司 | Cable fault tester |
| CN104297624A (en) * | 2014-11-06 | 2015-01-21 | 国家电网公司 | Direct current ground fault detecting and handling method |
| CN104849676A (en) * | 2015-01-12 | 2015-08-19 | 国家电网公司 | DC insulation monitoring device for signal injection method |
| CN106556774A (en) * | 2015-09-25 | 2017-04-05 | 浙江科畅电子有限公司 | Overhead transmission line grounding fault searching instrument |
| CN110231534A (en) * | 2019-05-22 | 2019-09-13 | 上海思创电器设备有限公司 | Device for measuring capacitance and parallel resistance of single capacitor |
-
2005
- 2005-05-09 CN CN 200520019966 patent/CN2890943Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101995518A (en) * | 2009-08-11 | 2011-03-30 | 中国铝业股份有限公司 | Aluminium electrolysis bus system resistance to ground detection device and detection method thereof |
| CN102879682A (en) * | 2012-09-26 | 2013-01-16 | 国家电网公司 | Cable fault tester |
| CN104297624A (en) * | 2014-11-06 | 2015-01-21 | 国家电网公司 | Direct current ground fault detecting and handling method |
| CN104849676A (en) * | 2015-01-12 | 2015-08-19 | 国家电网公司 | DC insulation monitoring device for signal injection method |
| CN106556774A (en) * | 2015-09-25 | 2017-04-05 | 浙江科畅电子有限公司 | Overhead transmission line grounding fault searching instrument |
| CN110231534A (en) * | 2019-05-22 | 2019-09-13 | 上海思创电器设备有限公司 | Device for measuring capacitance and parallel resistance of single capacitor |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |