CN106019063A - Fault indicator and fault detecting method - Google Patents

Fault indicator and fault detecting method Download PDF

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Publication number
CN106019063A
CN106019063A CN201610621638.6A CN201610621638A CN106019063A CN 106019063 A CN106019063 A CN 106019063A CN 201610621638 A CN201610621638 A CN 201610621638A CN 106019063 A CN106019063 A CN 106019063A
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CN
China
Prior art keywords
fault
circuit
kinds
frequency
filter
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Pending
Application number
CN201610621638.6A
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Chinese (zh)
Inventor
赵传宗
穆景龙
裴玉杰
张炬
张文广
李春东
刘剑
徐建国
关春梅
张丽
黄钢
肖天然
王清昊
赵宏
牛开顺
王莹
赵孟臣
卢岩
倪国立
姜洪
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LIAONING ELECTRIC PROVER DEVELOPMENT Co Ltd
LIAONING TUOXIN POWER ELECTRONIC Co Ltd
State Grid Corp of China SGCC
State Grid Liaoning Electric Power Co Ltd
Original Assignee
LIAONING ELECTRIC PROVER DEVELOPMENT Co Ltd
LIAONING TUOXIN POWER ELECTRONIC Co Ltd
State Grid Corp of China SGCC
State Grid Liaoning Electric Power Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by LIAONING ELECTRIC PROVER DEVELOPMENT Co Ltd, LIAONING TUOXIN POWER ELECTRONIC Co Ltd, State Grid Corp of China SGCC, State Grid Liaoning Electric Power Co Ltd filed Critical LIAONING ELECTRIC PROVER DEVELOPMENT Co Ltd
Priority to CN201610621638.6A priority Critical patent/CN106019063A/en
Publication of CN106019063A publication Critical patent/CN106019063A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections

Abstract

The invention relates to a fault indicator and a method. The fault indicator comprises a sampling circuit, a filtering circuit and a detecting circuit, wherein the sampling circuit, the filtering circuit and the detecting circuit are used for collecting, filtering and detecting two types of frequency signals of the circuits respectively. The fault indicator further comprises a calculating unit which calculates a double-frequency measurement current ratio according to a detection output result, a judging unit which judges whether the next stage of the fault indicator has single-phase grounding faults or not according to the calculation result, and a communication module which transmits the judgment result and the calculation result to a monitoring system. By sampling two frequencies, calculating the signal ratio of the frequencies and judging whether single-phase grounding faults exist or not, on-site judgment can be achieved, accuracy can be improved, fault points can be directly reported, uploaded data is small, accuracy is high, a fault positioning and detecting method of a fault point direct reporting system is simpler, and the fault points are effectively positioned.

Description

Fault detector and fault detection method
Technical field
The present invention relates to a kind of fault detector and fault detection method.
Background technology
Fault detector is to carry out whether comprehensive descision exists singlephase earth fault by the synthesis zero-sequence current data being reported to monitoring system at present, uses the method, and system structure is complicated.And owing to wanting three synthesis zero-sequence currents, and these three synthesis zero-sequence current is the most asynchronous, and produce error, the signal data amount additionally gathered is bigger, and the outage probability of GPRS transmission mode is bigger, so can cause loss of data, thus the information reported is forbidden.Additionally alarm can not be reported to the police on the spot, after needing to be judged by monitoring system, monitoring system sends alarm signal.
Summary of the invention
The technical problem to be solved is, the shortcoming overcoming prior art, it is provided that fault detector and method, this indicator and method can make accuracy improve, can realize judging on the spot, make system failure position finding and detection method simpler, effectively carry out localization of fault.
The present invention solves the technical scheme of above technical problem: fault detector, including sample circuit, filter circuit and testing circuit, two kinds of frequency signals of circuit are acquired, filter and detect by respectively, described fault detector also includes the arithmetic element measuring current ratio according to detection output result computing double frequency, whether the next stage according to operation result failure judgement indicator exists the judging unit of singlephase earth fault, and the indicating module of enabling signal instruction and will determine that result and operation result transmission to monitoring system communication module.
The present invention solves above technical problem and also proposes a kind of technical scheme: indicating fault method, sample circuit, filter circuit and testing circuit is used respectively two kinds of frequency signals of circuit to be acquired, filter and detected, calculate the current value of two kinds of frequency signals, according to two kinds of frequency current ratios, automatic discrimination singlephase earth fault, and provide signal designation and send monitoring system afield by communication module.
The invention has the beneficial effects as follows: by two kinds of frequencies of sampling, calculate its signal ratio, thus judge whether singlephase earth fault, can realize judging on the spot, and improve accuracy, additionally can direct reporting fault point, uploading data few, accuracy rate is high, report point direct to fault.System failure position finding and detection method is simpler, effectively carries out localization of fault.
Accompanying drawing explanation
Fig. 1 is fault indicator circuitry theory diagram of the present invention;
Fig. 2 is malfunction indicator system initializers flow chart of the present invention;
Fig. 3 fault detector of the present invention each branch process program flow diagram;
Fig. 4 fault detector of the present invention I/O interrupt image-processing program flow chart;
Fig. 5 fault detector of the present invention AD compares interrupt handling routine flow chart;
Fig. 6 fault detector of the present invention house dog interrupt handling routine flow chart;
Fig. 7 fault detector of the present invention sampling filter schematic block circuit diagram;
Fig. 8 is single-phase earth fault detecting method circuit theory diagrams of the present invention;
Fig. 9 is the present invention low excitation impedance transformer grounding protection device circuit theory diagrams.
Detailed description of the invention
Embodiment 1
As shown in Figure 8; for single-phase earth fault detecting method circuit theory diagrams of the present invention; the phase-to-ground fault detection principle injecting double frequency characteristic signal through low excitation impedance transformator is as follows: when there is singlephase earth fault; low excitation impedance transformer grounding device action, implements parallel shunt protection at fault phase.Injecting double frequency detection signal by low excitation impedance transformator, the lowest excitation impedance transformator is signal voltage source, and detects signal and exist only in fault phase.
Have under a kind of frequency effect:
I1=U/Xc1+U/Xc2+U/R
I2=U/Xc2
Wherein U is Injection Signal voltage, and Xc is circuit capacitive reactance, and R is earth resistance;
Changing Injection Signal frequency, keep Injection Signal voltage constant, owing to capacitive reactance is inversely proportional to frequency, k is two kinds of frequency ratio, now:
I11=k.U/Xc1+k.U/Xc2+U/R
I21=k.U/Xc2
Two kinds of frequency measurement carry out ratio computing:
I11/I1=(k.U/Xc1+k.U/Xc2+U/R)/(U/Xc1+U/Xc2+U/R)!=k
I21/I2=(k.U/Xc2)/(U/Xc2)=k
The non-faulting loop same I2 of testing result.For non-faulting measure loop, impedance loop is capacitive, and current ratio is driven and is bordering on K, and for fault detect loop, impedance loop is the resistive capacitive that adds, and current ratio is less than K, in the case of Injection Signal frequency is known, it is easy to distinguish fault loop and fault section.
On the one hand the single-phase earth fault detecting method injecting two-frequency signal through low excitation impedance transformator uses signal voltage source to avoid conventional current source signal method for implanting, and by distribution capacitive reactance shunt influence, fault loop signal characteristic is inconspicuous;On the other hand using two-frequency signal injection mode, single-phase earthing judgment basis is the ratio of two kinds of frequency signal detected values, is not affected by factors such as line properties, geographical conditions, fault detector certainty of measurement, installing zone spacings.
Based on above-mentioned know-why, low excitation impedance transformer grounding protection device is as follows:
As it is shown in figure 9, low excitation impedance transformer grounding protection device includes a ground protection cabinet and linear quadratic control screen.Primary equipment includes: single-phase circuit breaker, low excitation impedance transformator, zero sequence current mutual inductor, switch cabinet and associated satellite accessory;Secondary device includes control panel 1 i.e. one-phase ground protection control unit and signal generator and signal generator, and one-phase ground protection control unit includes single-phase earthing phase-controlled unit, earthing wire-selecting unit and drives locking unit.It is the core of power distribution network single-phase grounding comprehensive protecting device, it is achieved the functions such as ground connection phase selection, route selection, fault phase impedance measurement.Switch K1, K2, K3 one end of single-phase circuit breaker 2 is connected with substation bus bar respectively, and the other end is connected with grounded screen 6 through low excitation impedance transformator.It is in gate-dividing state when system is properly functioning, is one fault phase to be forced equipotential executive component with the earth, and be provided with electrically and program locking each other, the most only allow a phase breaker closing.Low excitation impedance transformator 3 includes three coils, and respectively primary winding W1, secondary secondary coil W2 and main secondary coil W3, wherein primary winding W1 one end is connected with single-phase circuit breaker 2, and the other end is connected with grounded screen 6;Secondary secondary coil W2 is connected with one-phase ground protection control unit 1;For signal measurement;Main secondary coil W3 is connected with signal generator 4, for coupling frequency signal.The end that controls of described signal generator is connected with the outfan of one-phase ground protection control unit; described signal generator is the signal generator that can produce the second frequency; described one-phase ground protection control unit includes the memory element for control store instruction; with the processor unit of the control instruction sending two kinds of frequencies of generation after single-phase circuit breaker closes a floodgate to signal generator, described signal generator includes that the control instruction that the outfan according to one-phase ground protection control unit sends produces the processor unit processing order of two kinds of frequencies.Described signal generator instructs according to one-phase ground protection control unit, injects two kinds of frequency signals to system, for fault location and fault automatic resetting.Described two kinds of frequencies can be set as required, it is also possible to selecting two kinds of frequencies is all high-frequency signal.The most concrete mode be use the first frequency be 75Hz, the second frequency is 225Hz, and the second frequency signal is high-frequency signal.Zero sequence current mutual inductor 5 is arranged between low excitation impedance transformator and grounded screen on line, for measuring the earth current flowing through low excitation impedance transformator.The Grounding of power distribution network one-phase ground protection device, determines the effect of ground protection, matching requirements and grounded screen good connection, reduces impedance ground as far as possible.Described ground connection phase-controlled unit includes first frequency filter circuit and the first testing circuit, the filtering signal that first frequency filter circuit produces exports to the first testing circuit, described first frequency filter circuit is the filter circuit that can filter two kinds of frequencies, in the present embodiment, the circuit that this filter circuit can use two band filters to be in parallel realizes, and described ground connection phase-controlled unit also includes the arithmetic element according to detection output result arithmetic system impedance ground and controls the control unit of single-phase circuit breaker separating brake according to operation result.
Work process: the singlephase earth fault location shielding system Real-time Collection substation busbars phase that low excitation impedance transformator signal injects, line voltage, residual voltage, separate with or without singlephase earth fault and ground connection with the modular angle of line voltage change judgement system according to residual voltage, when there is singlephase earth fault, control corresponding separate single-phase earthing chopper (K1, K2, K3) rapid closing, after corresponding separate single-phase circuit breaker closes a floodgate, force fault phase isoelectric level over the ground, realize extinguishing ground arc, human body electrification is provided effectively protection simultaneously, personal injury accident is avoided to occur.When ground property is intermittent ground connection, unstable state ground connection can be changed into stable metal ground connection by this device, it is to avoid the generation of intermittent overvoltage.
Ground protection circuit selection unit carries out recording ripple before and after single-phase earthing breaker actuation, according to the change before and after split-phase breaker closing of each circuit zero-sequence current, uses zero-sequence current characteristic equation, determines earth fault line.
After single-phase circuit breaker closes a floodgate, through setting time delays, enabling signal generator, particular frequencies voltage is injected to system by the low excitation impedance transformator main secondary coil W3 being connected with signal generator, produce earth current, ground connection phase-controlled unit gathers voltage and the current signal of low excitation impedance transformator pair secondary coil W2 feedback, isolate the particular frequencies signal wherein injected, calculate system earth impedance variation, as impedance ground recovers to system normal condition, differentiate that earth fault disappears, ground connection phase-controlled unit controls single-phase circuit breaker (K1, K2, K3) separating brake, realize singlephase earth fault automatic resetting.
1, the specific embodiment of the present invention is as follows: as shown in Figures 1 to 6, fault detector, including sample circuit, filter circuit and testing circuit, two kinds of frequency signals of circuit are acquired, filter and detect by respectively, described fault detector also includes the arithmetic element measuring current ratio according to detection output result computing double frequency, whether the next stage according to operation result failure judgement indicator exists the judging unit of singlephase earth fault, and will determine that result and operation result transmission to monitoring system communication module.Also include the indicating module according to the instruction of judged result enabling signal.Signal can be signal lights can also be alarm, it is possible to be both combinations.Described two kinds of frequency filter circuits can realize in the way of using two narrow band filters in parallel.Current ratio then can use the ratio of current amplitude to calculate.
It is illustrated in figure 7 fault detector sampling filter schematic block circuit diagram; it is the embodiment of the second wave filter of the present invention; the application protect for low current grounding based on signal injection method in Injection Signal owing to amplitude is less, serious interference and cause the present situation of detection difficult; have studied a kind of analog filtering and Injection Signal detection method that digital filtering combines, separately design analog filter and digital filter.The method has higher sensitivity and reliability, is entirely capable of meeting the requirement of scene application.The injection current signal of 1mA can be precisely separating out in the current signal of power frequency 5A and effectively calculate by the method.Wherein sensor loop is CT sample circuit, secondary filter amplifying circuit is with one-level filter amplification circuit, the add circuit positive half period that is added to by the filtering signal of negative half-cycle goes, through hardware above circuit, it would be desirable to signal sends into the A/D module of CPU through CPU computational analysis.After the collection of analogue signal amount after direct current and harmonic, then carry out fast Fourier calculating through digital narrowband bandpass filtering extraction Injection Signal frequency component.Can accurately calculate the virtual value of the signal that comes in and goes out through fast Fourier transform after filtering.
Embodiment 2
As shown in Figures 1 to 6, indicating fault method, sample circuit, filter circuit and testing circuit is used respectively two kinds of frequency signals of circuit to be acquired, filter and detected, calculate the current value of two kinds of frequency signals, according to two kinds of frequency current ratios, automatic discrimination singlephase earth fault, and send monitoring system afield by communication module.When determining singlephase earth fault, provide signal designation.
The above is only the preferred embodiment of the present invention; it is not limited to the present invention; should be understood that; for those skilled in the art; on the premise of without departing from the technology of the present invention principle; can also make some improvement and modification, these improve and modification also should be regarded as protection scope of the present invention.

Claims (4)

1. fault detector, it is characterised in that: including sample circuit, filter circuit and testing circuit, two kinds of frequency signals of circuit are acquired, filter and detect by respectively;Also include the arithmetic element measuring current ratio according to detection output result computing double frequency, whether the next stage according to operation result failure judgement indicator exists the judging unit of singlephase earth fault, and will determine that result and operation result transmission to monitoring system communication module.
Fault detector the most according to claim 1, it is characterised in that: also include the indicating module according to the instruction of judged result enabling signal.
3. fault detection method, it is characterized in that: use sample circuit, filter circuit and testing circuit respectively two kinds of frequency signals of circuit to be acquired, filter and detected, calculate the current value of two kinds of frequency signals, according to two kinds of frequency current ratios, automatic discrimination singlephase earth fault, and send monitoring system afield by communication module.
Fault detection method the most according to claim 3, it is characterised in that: when determining singlephase earth fault, provide signal designation.
CN201610621638.6A 2016-08-02 2016-08-02 Fault indicator and fault detecting method Pending CN106019063A (en)

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Application Number Priority Date Filing Date Title
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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109412122A (en) * 2018-11-05 2019-03-01 国电南瑞科技股份有限公司 Pouring-in low-voltage intelligent switch
CN110470945A (en) * 2019-07-15 2019-11-19 福建省万维新能源电力有限公司 A kind of power transmission and transformation line fault detecting and positioning method

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2773704Y (en) * 2005-03-29 2006-04-19 吕强 Overhead grounded short-circuit fault indicator
CN101738565A (en) * 2010-01-14 2010-06-16 北京双杰电气股份有限公司 Adaptive fault indicator
CN103344884A (en) * 2013-07-11 2013-10-09 杜海滨 Electricity overhead line fault two-frequency-signal detecting positioning method and dedicated position indicator thereof
CN203490324U (en) * 2013-09-04 2014-03-19 天津航空凯通机电有限公司 Cable fault indicator
US20140229126A1 (en) * 2011-07-18 2014-08-14 Xi Hu Fault detection method and device
CN204679575U (en) * 2015-04-17 2015-09-30 北京水木源华电气股份有限公司 Overhead grounded short-circuit fault indicator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2773704Y (en) * 2005-03-29 2006-04-19 吕强 Overhead grounded short-circuit fault indicator
CN101738565A (en) * 2010-01-14 2010-06-16 北京双杰电气股份有限公司 Adaptive fault indicator
US20140229126A1 (en) * 2011-07-18 2014-08-14 Xi Hu Fault detection method and device
CN103344884A (en) * 2013-07-11 2013-10-09 杜海滨 Electricity overhead line fault two-frequency-signal detecting positioning method and dedicated position indicator thereof
CN203490324U (en) * 2013-09-04 2014-03-19 天津航空凯通机电有限公司 Cable fault indicator
CN204679575U (en) * 2015-04-17 2015-09-30 北京水木源华电气股份有限公司 Overhead grounded short-circuit fault indicator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109412122A (en) * 2018-11-05 2019-03-01 国电南瑞科技股份有限公司 Pouring-in low-voltage intelligent switch
CN110470945A (en) * 2019-07-15 2019-11-19 福建省万维新能源电力有限公司 A kind of power transmission and transformation line fault detecting and positioning method

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