CN105137292B - Direct current signal intelligent acquisition device for high-tension cable fault location - Google Patents

Direct current signal intelligent acquisition device for high-tension cable fault location Download PDF

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Publication number
CN105137292B
CN105137292B CN201510609209.2A CN201510609209A CN105137292B CN 105137292 B CN105137292 B CN 105137292B CN 201510609209 A CN201510609209 A CN 201510609209A CN 105137292 B CN105137292 B CN 105137292B
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signal
cable
circuit
voltage
filter circuit
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CN105137292A (en
Inventor
何光华
俞骏
浦仕亮
陈伟嵩
孔德武
孙庆明
刘伟强
谢江虹
韩刚
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SHANGHAI WELLDONE ELECTRIC EQUIPMENT CO Ltd
State Grid Corp of China SGCC
Wuxi Power Supply Co of Jiangsu Electric Power Co
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SHANGHAI WELLDONE ELECTRIC EQUIPMENT CO Ltd
State Grid Corp of China SGCC
Wuxi Power Supply Co of Jiangsu Electric Power Co
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Abstract

The invention discloses a kind of direct current signal intelligent acquisition device for high-tension cable fault location.The present invention in cable one end by applying stabling current signal, direct current signal intelligent acquisition device is connected to the test lead of tested cable and relief cable, another terminals short circuit of cable, harvester automatic data collection simultaneously handles voltage and current signal, by analog- and digital- filtering, the intelligent voltage comparison method of can application afterwards directly displays trouble point percentage and trouble point distance test end distance.It is an advantage of the invention that this direct current signal intelligent acquisition device for being used for complex high voltage cable system fault location in power transmission network improves cable fault search efficiency, shorten power off time, improve power supply reliability, there is good market application value.

Description

Direct current signal intelligent acquisition device for high-tension cable fault location
Technical field
The present invention relates to a kind of electric power system fault positioner, is used to search power cable fault more particularly to one kind The direct current signal intelligent acquisition device of point.
Background technology
High-tension cable is taken up an area less with it, lays convenience, personal safety guarantee, power supply reliability is high, maintenance workload is few etc. Advantage is widely applied in high voltage power transmission and transforming network.The rapid development built with China large- and-medium size cities and city rule The requirement drawn, the scale of power system power transmission and transformation network is also increasing, the high voltage power transmission and transforming of especially 110kV and ratings above Network.Cable in network, and a complicated system, may contain GIS terminal;T joints may be contained;May be length Circuit, include multiple cross interconnected sections.Insulation breakdown once occurs for cable, often several days can not fault point, delay power supply Time, reduce power supply reliability.
Utilized in the market for cable fault positioning is main in 110kV and above power transmission and transformation network Murray bridge methods and traveling wave reflect two kinds.
And be classical method to breakdown point location using Murray electric bridges, it is convenient and accurate, such as Fig. 1.But electric bridge can only Percentage is obtained, it is artificial to calculate trouble point distance.Sometimes some failure electric bridges can not also position, and main cause is:Close on operation The load current of cable produces power frequency magnetic field, and in failure cable XY, and relief cable MN, the region XYNM surrounded produces induced electricity Pressure.In galvanometric 2 end M, X-shaped into 100V power-frequency voltage can be can exceed that, and it is used for the DC potential difference that positions only mV levels. Therefore, galvanometer is easily damaged, or can not be balanced, or because exchange participates in bridge balance, localization ratio error is very big.
Traveling wave bounce technique is mainly secondary pulse process, three times impulse method and pulse current method.The ripple that pulse current method measures Shape is complicated, understands difficulty of getting up, the reflected impulse that babe in the wood is difficult to be out of order a little.Such as Fig. 2, secondary pulse process is protected The way of pulse current method high-voltage signal breakdown fault point has been stayed, Low Voltage Impulse Method is introduced to the test of high resistive fault, made Waveform is easier to understand, and is easy to grasp.Such as Fig. 3, impulse method three times, first by high pressure short-time pulse breakdown fault point, followed by Press pulse to maintain sufficiently long arcing, make action of low-voltage pulse synchronously relatively reliable.But because high-tension cable possesses cross interconnected, T joints, Wave impedance produces mutation, makes positioning back wave sufficiently complex, it is difficult to position, high-voltage pulse also has energy loss in the point, it is difficult to Reach at a distance.
The content of the invention
In view of the above-mentioned problems, exploring and summarizing the experience by substantial amounts of, the present invention proposes a kind of be used in power transmission network The direct current signal intelligent acquisition device of complex high voltage cable system fault location improves cable fault search efficiency.
According to technical scheme provided by the invention, the described direct current signal intelligent acquisition for high-tension cable fault location Device includes:Sampled voltage protection filter circuit, sample rate current protection filter circuit, sample resistance, signal amplification and AD conversion Circuit and intelligent processing unit, two inputs of sampled voltage protection filter circuit are connected to tested cable and auxiliary The test lead of cable is helped, external high-voltage constant current source is connected respectively to the test of tested cable and relief cable by sample resistance End, another terminals short circuit of tested cable and relief cable, two inputs of sample rate current protection filter circuit connect The both ends of sample resistance are connect, the sampled voltage protection filter circuit, the output end of sample rate current protection filter circuit pass through respectively Cross signal amplification and A/D convertor circuit all the way and be connected to intelligent processing unit;The sampled voltage protection filter circuit is used to suppress High frequency, high-voltage pulse and elimination exchange and high frequency background interference signal in sampled voltage, filtered signal is transferred to Rear stage signal amplifies and A/D convertor circuit;High frequency that sample rate current protection filter circuit is used to suppress in sample rate current, High-voltage pulse and elimination exchange and high frequency background interference signal, filtered signal is transferred to the amplification of rear stage signal and AD Change-over circuit;The signal amplification and A/D convertor circuit amplify DC small signal, and DC voltage, current analog signal are turned Digital data transmission is changed to intelligent processing unit.
Specifically, the sampled voltage protection filter circuit includes:Sampled voltage protects two inputs of filter circuit Air discharge tube CR1 both ends, filter capacitor C1 both ends, common mode inductance L1 two inputs are connected respectively, common mode inductance L1's Two output ends connect piezo-resistance RV1 both ends, filter capacitor C2 both ends, filter capacitor C2 one end connection resistance R1 mono- respectively End, filter capacitor C2 other ends connection filter capacitor C3 one end are simultaneously grounded, the resistance R1 other ends and filter capacitor C3 other end phases Connect and be used as signal output part.The sample rate current protection filter circuit is identical with sampled voltage protection filter circuit construction.
Specifically, the signal amplification and A/D convertor circuit use analog-digital converter AD7715.The signal amplification and AD I is used between change-over circuit and intelligent processing unit2C buses are connected.
It is an advantage of the invention that:The present invention is satisfactory straight using small signal process acquisition technique and filtering technique design Flow signal intelligent harvester.Harvester is placed in hot end, and display screen and operation are also placed in hot end.Harvester Powerful filter function, can filter out the AC influence of 200V peak values in the short time, and and can accurately detects the direct current signal of tens microvolts. Therefore, this direct current signal intelligent acquisition device for being used for complex high voltage cable system fault location in power transmission network improves cable Trouble shoot efficiency, shorten power off time, improve power supply reliability, there is good market application value.
Brief description of the drawings
Fig. 1 is bridge method positioning schematic.
Fig. 2 is secondary pulse process schematic diagram.
Fig. 3 is impulse method schematic diagram three times.
Fig. 4 is the implementation principle figure of the present invention.
Fig. 5 is circuit structure block diagram of the present invention.
Fig. 6 is sampled voltage protection filter circuit schematic diagram.
Fig. 7 is sample rate current protection filter circuit schematic diagram.
Fig. 8 is signal amplification and A/D convertor circuit schematic diagram.
Fig. 9 is intelligent processing unit circuit theory diagrams.
Embodiment
The invention will be further described with reference to the accompanying drawings and examples.
Collection technology, filtering technique, modern communications technology, high and low voltage isolation technology are applied to high pressure by the present invention Cable fault is searched in equipment.High-tension cable fault location difficult point is voltage height, may be several kilovolts;Hz noise is big, may Up to 200V;Tested direct current signal is small, may there was only tens microvolts.Therefore a harvester can be designed, be resistant to over the ground 10kV voltages, there is powerful filter function, there is sampling with high precision AD, between analog signal and data signal using optocoupler every From, by insulation bar connect a key operation switch be available for human body directly to operate.
Overall trouble shoot scheme is:By applying stabling current signal in cable one end, direct current signal is intelligently adopted Acquisition means are connected to the test lead of tested cable and relief cable, another terminals short circuit of cable, harvester automatic data collection And voltage and current signal is handled, by analog- and digital- filtering, the intelligent voltage comparison method of can application afterwards directly displays Trouble point percentage and trouble point distance test end distance.Principle is as shown in Figure 4.
As shown in figure 5, the direct current signal intelligent acquisition device for high-tension cable fault location of the present invention includes:Sampling At voltage protection filter circuit, sample rate current protection filter circuit, sample resistance, signal amplification and A/D convertor circuit and intelligence Unit is managed, two inputs of the sampled voltage protection filter circuit are connected to the test of tested cable and relief cable End, external high-voltage constant current source is connected respectively to the test lead of tested cable and relief cable by sample resistance, described tested Try cable and another terminals short circuit of relief cable(Tubbiness wiring), two inputs connection of sample rate current protection filter circuit The both ends of sample resistance, the sampled voltage protection filter circuit, the output end of sample rate current protection filter circuit are passed through respectively Signal amplification and A/D convertor circuit are connected to intelligent processing unit all the way.
Signal processing flow is described as follows:
1st, signal inputs:The loop-around test voltage and current signal formed to failure cable and relief cable.
2nd, sampled voltage protection filter circuit and sample rate current protection filter circuit are respectively completed to sampled voltage and sampling The signal protection and signal filter function of electric current.
Wherein signal protection refers to:Signal input circuit is protected, mainly suppresses high frequency, high-voltage pulse to rear stage The interference of analog circuit and digital circuit.
Signal filtering refers to:Exchange and high frequency background interference signal are eliminated, extracts accurate DC voltage and current information. Filtered signal is transferred to rear stage amplifying circuit.
3rd, signal amplification and A/D convertor circuit enter to the DC small signal of the next effective voltage of front stage circuits transmission, electric current Row amplification, then carry out A/D conversion, i.e.,:DC voltage and current analog signal are converted into data signal, are easy to following digital electric Road is handled.
4th, intelligent processing unit:Small DC voltage and current digital signal are gathered, Intelligent Calculation, is further filtered, Garbage is rejected, analysis calculating is carried out to data, obtains the positional information of Method of Cable Trouble Point.Intelligent processing unit needs to handle Digit manipulation turn-knob information, to carry out operational control and parameter setting to harvester.Intelligent processing unit is by result of calculation Shown on a display screen with collection voltages, current signal information.It can be shown on display screen with display system parameter setting information Function menu.
If Fig. 6,7 is sampled voltage, current protection and filter circuit respectively.Sampled current signals Itest is by sampling electricity R conversion voltage signals are hindered, remaining two circuit is just the same.Said below so that sampled voltage protects filter circuit as an example It is bright.As shown in fig. 6, sampled voltage protection filter circuit includes:Two inputs of sampled voltage protection filter circuit connect respectively Air discharge tube CR1 both ends, filter capacitor C1 both ends, common mode inductance L1 two inputs are connect, two of common mode inductance L1 are defeated Go out end and connect piezo-resistance RV1 both ends, filter capacitor C2 both ends, filter capacitor C2 one end connection resistance R1 one end, filtering respectively The electric capacity C2 other ends connect filter capacitor C3 one end and are grounded, and the resistance R1 other ends are connected with the filter capacitor C3 other ends and conduct Signal output part.
Air discharge tube CR1, piezo-resistance RV1 are for absorbing peak pulse.Common mode inductance L1 suppression common mode signals Entering signal is amplified and AD conversion loop.Resistance R1 and electric capacity C3 composition RC low-pass filter circuits, suppress Hz noise.
The signal of voltage and current amplifies as A/D convertor circuit, illustrates below by taking voltage circuit as an example.As shown in Figure 8 Circuit complete RC filtering, amplifier amplification and AD conversion.
U1 is four pin crystal oscillators, and pin has OE ends, VCC ends, GND ends, OUT terminal.U2 is chip AD7715.AD7715 is a Technical grade is adapted to the full simulation front end of low frequency measurement application, can directly receive the low imput from sensor, and Produce serial digital output.AD7715 uses sigma-delta switch technology, and highest 16 can be achieved without mistake code performance.Physical circuit is: Voltage(Electric current)Signal passes through 7 pin of resistance R5 connection electric capacity C8 one end, voltage-regulator diode Z1 negative electrodes and AD7715, electric capacity C8 The other end, voltage-regulator diode Z1 anodes, AD7715 8 pin ground connection;Resistance R4 mono- terminates supply voltage VDD, another termination capacitor 6 pin of C7 one end, electrochemical capacitor C9 anodes and AD7715, the electric capacity C7 other ends, electrochemical capacitor C9 negativing ending groundings;Resistance R6 mono- Termination power voltage VDD, another termination capacitor C10 one end, electrochemical capacitor C11 anodes, AD7715 15 pin, the VCC ends of crystal oscillator And electric capacity C12 one end, the electric capacity C10 other ends, electrochemical capacitor C11 negative terminals, the electric capacity C12 other ends, crystal oscillator GND ends, AD7715 4 pin, 10 pin, 11 pin, 16 pin ground connection;The OUT terminal of crystal oscillator connects AD7715 2 pin;AD7715 9 pin connect positive reference Voltage(2.5V).
Resistance R5 and electric capacity C8 forms capacitance-resistance LPF, voltage-stabiliser tube Z1 overvoltage protections.Resistance R4, electric capacity C7, C9 are formed Capacitance-resistance LPF, power filter.Resistance R6, electric capacity C10, C11 form capacitance-resistance LPF, power filter.U2 12,13, 14th, 1,5 pin are control pin, can be handled by mcu programming, amplifier gain and AD sampling ranges inside control AD7715.
As shown in figure 9, intelligent processing unit circuit is mainly made up of U5, P5, P6, wherein U5 is embedded microprocessor ATmega64, the processor is low in energy consumption when working, anti-electromagnetic interference capability is strong, is a industrial level processor, is intelligent data The core component of processing unit, special data acquisition and processing routine are embedded with, respectively before processing step voltage, the A/D of electric current The data-signal of output is changed, I is used between A/D change-over circuits and microprocessor U52C bus high speed transmission datas.P5 and P6 For liquid crystal display, for showing intelligent processing unit result of calculation, display system parameter setting information, function menu.
The intelligent processing unit data acquisition and processing routine sampled voltage and current signal, utilize digital filtering Algorithm rejects interference signal and valid data is optimized.According to user's needs, software convert automatically different cross section cable length Degree, according to test result calculations and shows abort situation percentage and trouble point distance.Software realizes three kinds of fault distances automatically Computational methods:Method of section, voltage comparison method and bridge method.Specific algorithm can use prior art, can also further research and develop.

Claims (2)

1. for the direct current signal intelligent acquisition device of high-tension cable fault location, including:Sampled voltage protection filter circuit, adopt Sample current protection filter circuit, sample resistance, signal amplification and A/D convertor circuit and intelligent processing unit, sample rate current protection The both ends of two inputs connection sample resistance of filter circuit, the sampled voltage protection filter circuit, sample rate current protection The output end of filter circuit is connected to intelligent processing unit by the amplification of signal all the way and A/D convertor circuit respectively;The sampling electricity High frequency, high-voltage pulse and the elimination exchange and high frequency background interference letter that pressure protection filter circuit is used to suppress in sampled voltage Number, filtered signal is transferred to the amplification of rear stage signal and A/D convertor circuit;The sample rate current protection filter circuit is used In suppressing the high frequency in sample rate current, high-voltage pulse and elimination exchange and high frequency background interference signal, by filtered signal It is transferred to the amplification of rear stage signal and A/D convertor circuit;
It is characterized in that two inputs of the sampled voltage protection filter circuit are connected to tested cable and relief cable Test lead, external high-voltage constant current source is connected respectively to the test lead of tested cable and relief cable by sample resistance, described Tested cable and another terminals short circuit of relief cable, the signal amplification and A/D convertor circuit amplify DC small signal, And DC voltage, current analog signal are converted into digital data transmission to intelligent processing unit;The signal amplification and AD turn Change and I is used between circuit and intelligent processing unit2C buses are connected;
The sampled voltage protection filter circuit includes:Two inputs of sampled voltage protection filter circuit connect air respectively Discharge tube CR1 both ends, filter capacitor C1 both ends, common mode inductance L1 two inputs, common mode inductance L1 two output ends point Not Lian Jie piezo-resistance RV1 both ends, filter capacitor C2 both ends, filter capacitor C2 one end connection resistance R1 one end, filter capacitor C2 The other end connects filter capacitor C3 one end and is grounded, and the resistance R1 other ends are connected with the filter capacitor C3 other ends and are used as signal defeated Go out end.
2. it is used for the direct current signal intelligent acquisition device of high-tension cable fault location as claimed in claim 1, it is characterized in that, it is described Signal amplifies and A/D convertor circuit uses analog-digital converter AD7715.
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CN106353643B (en) * 2016-11-09 2019-05-28 雷细军 Resistance ratio electric cable failure detector
CN106353657A (en) * 2016-11-28 2017-01-25 国网福建省电力有限公司 High-voltage direct current cable partial discharge intelligent monitoring device and monitoring method
CN106483355A (en) * 2016-12-16 2017-03-08 中国电子科技集团公司第四十研究所 A kind of novel current transformer
CN107167678B (en) * 2017-05-08 2020-11-17 许继集团有限公司 Multifunctional analog signal acquisition circuit
DE102017122684A1 (en) * 2017-09-29 2019-04-04 Lisa Dräxlmaier GmbH TEST APPARATUS AND TEST METHOD FOR CHECKING A DATA CABLE FOR A POWER VEHICLE THROUGH CONSTANT CURRENT SOURCE
CN110346688B (en) * 2019-07-31 2021-03-02 广东电网有限责任公司 Method for rapidly judging and positioning faults of high-voltage complex cables of 110kV or above in segmented manner
CN110837025A (en) * 2019-11-15 2020-02-25 国网江苏省电力有限公司盐城供电分公司 Distribution line fault node identification system and method based on current analysis
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