CN102830327A - Judging method and device of single-phase grounding fault line of small-current grounding system - Google Patents
Judging method and device of single-phase grounding fault line of small-current grounding system Download PDFInfo
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- CN102830327A CN102830327A CN2012101988885A CN201210198888A CN102830327A CN 102830327 A CN102830327 A CN 102830327A CN 2012101988885 A CN2012101988885 A CN 2012101988885A CN 201210198888 A CN201210198888 A CN 201210198888A CN 102830327 A CN102830327 A CN 102830327A
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Abstract
The invention discloses a judging method and device of a single-phase grounding fault line of a small-current grounding system. The method comprises the following steps of: utilizing a traveling wave current sensor to measure traveling wave current signals of all feed lines of the small-current grounding system; utilizing a high-frequency coaxial cable to symmetrically transmit to send the traveling wave current signals to a signal processing circuit to carry out decaying and reshaping treatment; sending an output signal of the signal processing circuit to an amplitude discrimination circuit to carry out amplitude discrimination after being isolated by a photoelectric isolation circuit to obtain the traveling wave current signals of all the feed lines; and comparing the traveling wave current amplitude values of all the feed lines by adopting a judging module, wherein the feed line with the greatest traveling wave current amplitude value is the fault line. According to the judging method and device of the single-phase grounding fault line of the small-current grounding system, the fault line which is subjected to single-phase grounding is accurately judged so as to conveniently cut off the fault line in time in an artificial or intelligent manner, and guarantee the safety of a power utilization system.
Description
Technical field
The invention belongs to field of power, particularly a kind of method of discrimination of single-phase grounded malfunction in grounded system of low current line and device.
Background technology
In the small current neutral grounding system, when a feeder line generation single-phase earthing, fault current is little during more than two-phase short circuit or symmetrical three-phase shortcircuit, is not enough to make this fault feeder of fault feeder isolating switch action excision.But the voltage that singlephase earth fault but makes all perfect phase raises.Fault feeder does not excise; Singlephase earth fault does not disappear; Sound all electrical equipments mutually comprise that feeder cable, bus, line insulator etc. receive above-mentioned power-frequency overvoltage effect for a long time; Often form the insulation weakness and cause new ground connection, develop into two-phase or three-phase shortcircuit, the serious threat security of system.Therefore to this singlephase earth fault that accounts for fault sum nearly 80%; Accurately judge the fault wire that single-phase earthing takes place,, guarantee the safety of total system so that ability manual work or aptitude manner excise fault wire; And the faulty equipment of timely handling failure line, it all is very important restoring electricity as early as possible.
Because the singlephase earth fault steady-state current is little, transformer station's feeder line is many, and mid point both possibly be insulation, also possibly be through grounding through arc, also possibly be through high resistance grounding, on reliability, is difficult to satisfy the Operation of Electric Systems requirement based on the selection method of of ac.
In recent years; Disclose based on comparing the row ripple selection methods such as priority that travelling wave current polarity or row ripple arrive; Because fault traveling wave current methods check and analysis fault time domain is the us level; The fault traveling wave electric current continues to continue to use alternating current and detects suchly, is to be difficult to obtain the travelling wave current on the high pressure feeder line at the load side of CT with an I/V (current/voltage) sensor.And in the two-circuit, be identical to the fault traveling wave electric current of non-fault wire transmission with fault wire fault traveling wave current polarity, cause erroneous judgement according to the route selection of travelling wave current polarity through end.
Summary of the invention
For the above-mentioned technical matters that the method for discrimination that solves existing single-phase grounded malfunction in grounded system of low current line exists, the present invention provides a kind of method of discrimination and device of single-phase grounded malfunction in grounded system of low current line.
The technical scheme that the present invention solves the problems of the technologies described above may further comprise the steps:
1) with the travelling wave current signal of all feeder lines of travelling wave current sensor measurement small current neutral grounding system;
2) the travelling wave current signal is delivered to that signal processing circuit decays, shaping is handled with coaxial cable for high frequency symmetry transmission;
3) the output signal of signal processing circuit is delivered to amplitude discrimination circuit and is carried out amplitude discrimination after photoelectric isolating circuit is isolated, and obtains the travelling wave current amplitude of all feeder lines;
4) if the discrimination module size of the travelling wave current amplitude of all feeder lines relatively is I
Mf＞I
Mk, k=1 ... N, N are the sum of feeder line, k ≠ f, and then f is a fault wire.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, use in the said step 1) that zero sequence CT obtains zero sequence travelling wave current on the feeder line in the feeder line screen cabinet.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, use in the said step 1) A and C in the feeder line screen cabinet mutually CT obtain the reach the standard grade travelling wave current signal of preface of feeder line.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, adopt the travelling wave current converter unit to be connected on CT Secondary Winding line end in the said step 1) and obtain.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, use hood type travelling wave current sensor in the said step 1), obtain zero sequence or line preface travelling wave current signal.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, in the said step 4), N bar feeder line is cable entirely or is pole line entirely, if I
Mk≤
K=1 ... N, k ≠ f, judgement f is a fault wire, all the other are non-fault wire.
In the method for discrimination of above-mentioned single-phase grounded malfunction in grounded system of low current line, in the said step 4), in the N bar mixing feeder line, n bar cable wherein, (N-n) bar pole line, if
Cable feeder line: I
Mk≤
I
MfK=1... n, k ≠ f; Or pole line feeder line: I
Mk≤
K=n+1... N, k ≠ f; Judgement f is a fault wire.
A kind of discriminating gear of single-phase grounded malfunction in grounded system of low current line; Comprise travelling wave current sensor, coaxial cable for high frequency, signal processing circuit, photoelectric isolating circuit, amplitude discrimination circuit, discrimination module, said travelling wave current sensor obtains the travelling wave current signal of all feeder lines of small current neutral grounding system; With coaxial cable for high frequency symmetry transmission the travelling wave current signal of travelling wave current sensor is delivered to that signal processing circuit decays, shaping is handled; The output signal of signal processing circuit is delivered to photoelectric isolating circuit, after photoelectric isolating circuit is isolated, delivers to amplitude discrimination circuit and carries out amplitude discrimination, the travelling wave current amplitude of all feeder lines of amplitude discrimination circuit output; Discrimination module is the size of the travelling wave current amplitude of all feeder lines relatively, and travelling wave current amplitude the maximum is a fault wire.
Technique effect of the present invention is: the present invention utilizes the travelling wave current sensor to obtain the travelling wave current signal; Decay again, shaping, amplitude discrimination handle; Size according to the travelling wave current amplitude is confirmed fault wire; Can accurately judge the fault wire that single-phase earthing takes place,, guarantee the safety of using electricity system so that ability manual work or aptitude manner in time excise fault wire.
Below in conjunction with accompanying drawing the present invention is done further detailed description.
Description of drawings
Fig. 1 mid point isolated neutral system of the present invention singlephase earth fault line method of discrimination process flow diagram.
Fig. 2 feeder line screen cabinet is equipped with the route selection schematic diagram of zero sequence CT.
Fig. 3 feeder line screen cabinet does not have the route selection schematic diagram of zero sequence CT.
Fig. 4 is the structural drawing of the discriminating gear of single-phase grounded malfunction in grounded system of low current line among the present invention.
Embodiment
Fig. 1 is a mid point isolated neutral system singlephase earth fault line method of discrimination process flow diagram of the present invention, and the present invention utilizes the first fault traveling wave current amplitude of singlephase earth fault to confirm fault feeder, the steps include:
Step 1.1, N bar feeder fault travelling wave current amplitude I when accurately measuring single-phase earthing
Mk(k=1 ... N); Step 1.2, according to ordering relatively: I
Mf＞I
MkOr relatively according to definite value:
Cable feeder line: I
Mk≤
I
Mf(k=1... n, k ≠ f);
Pole line feeder line: I
Mk≤
(k=n+1... N, k ≠ f);
Judgement f is a fault feeder, and all the other are non-fault wire.
Wherein, I
MfBe the fault traveling wave current amplitude on the fault wire f,
I
Mk(k=1 ... N, but k ≠ f) is a fault traveling wave current amplitude on the non-fault wire.
Fig. 2 is the mid point isolated neutral system fault wire discrimination principles figure that zero sequence CT is housed in the feeder line screen cabinet among the present invention.Total N bar feeder line all is equipped with zero sequence CT, wherein L on the substation bus bar
1L
nBe cable feeder line, L
N+1L
NBe overhead feeder.Be connected on zero sequence CT secondary line end to the travelling wave current converter unit, and transmit with zero-sequence fault travelling wave current I on the accurate measurement high pressure feeder line with the coaxial cable for high frequency symmetry
Mk(k=1 ... N).Fault wire upward traveling wave current amplitude I
Mf:
I
mf=1.63
Non-fault wire upward traveling wave current amplitude I
Mk:
I
Mk=I
Mf * 
(k=1 ... N, but k ≠ f)
Wherein: U
rBe system's rated voltage, Z
fBe fault wire zero sequence wave impedance,
Z
k(k=1 ... N, but k ≠ f) is non-fault wire zero sequence wave impedance.Z=Z
1//Z
2…//Z
N。
Cablebreak impedance Z cab is far smaller than pole line wave impedance Z
AIR, and common small current neutral grounding system such as 10KV system, the cable feeder line is counted n more than the pole line number, more has:
I
Mf=1.63
, cable feeder line: I
Mk=I
Mf*
≤
(k=1 ... N, but k ≠ f)
Pole line feeder line: I
Mk=I
Mf*
≤
(k=n+1 ... N, but k ≠ f)
Fig. 3 is the mid point isolated neutral system fault wire method of discrimination schematic diagram that the feeder line cabinet is not adorned zero sequence CT.
Total N bar feeder line is not adorned zero sequence CT on the substation bus bar, but A, C two go up mutually CT, wherein L always are housed
1L
nBe cable feeder line, L
N+1L
NBe overhead feeder, be connected on A, C phase CT secondary line end to the travelling wave current converter unit, and with the transmission of coaxial cable for high frequency symmetry, with fault wire preface travelling wave current I on the accurate measurement feeder line
MkA, I
MkC
(1) ground connection takes place in the B of fault wire f mutually
I
mf=?I
mfA=?I
mfC=
*1.63
，
I
mk=I
mkA=I
mkC=I
mf?*?
(2) ground connection takes place in the A phase of fault wire f (or C phase)
I
mf=?I
mfA=?I
mfC=
*1.63
，
I
mk=I
mkA=I
mkC=I
mf?* 
Wherein: Ur is system's rated voltage, Z
fBe fault wire line preface wave impedance,
Z
kBe non-fault wire line preface wave impedance, (k=1 ... N, but k ≠ f).
Z=Z
1//Z
2…//Z
N
(3) cablebreak impedance Z cab is much smaller than pole line wave impedance Z
AIR, and common small current neutral grounding system such as 10kV system, the cable feeder line is counted n more than the pole line number, more has:
Cable feeder line: I
Mk=I
Mf*
≤
(k=1 ... N, but k ≠ f)
Pole line feeder line: I
Mk=I
Mf*
≤
(k=n+1 ... N, but k ≠ f)
Fig. 4 is based on the block diagram of neutral earthing of the present invention system single-phase fault line discriminating gear.
Comprise: travelling wave current converter unit, signal processing unit, route selection module and output module.The travelling wave current converter unit is accurately measured fault traveling wave electric current on the feeder line, and it comprises a personal module and directly is connected on feeder line screen cabinet CT secondary line end, and the travelling wave signal that is transformed to hundreds of volts transfers to signal processing unit with coaxial cable for high frequency.
Signal processing unit, to travelling wave signal decay, shaping, photoelectricity isolate and amplitude discrimination, obtains the zero-sequence component of fault traveling wave current amplitude: I
Mk, k=1 ... N, or line preface component I
MkA, I
MkC, k=1 ... N
The route selection module:
According to the zero-sequence component ordering relatively:
I
mk?﹤I
mf?(k=1,...?N?,?k≠f)。
Or definite value relatively: cable feeder line: I
Mk≤
(k=1 ... N, but k ≠ f)
Pole line feeder line: I
Mk≤
(k=n+ ... N, but k ≠ f)
According to the ordering of line preface component relatively
I
mkA?﹤?I
mfA(k=1,...?N?,?k≠f)。
Or definite value relatively: cable feeder line: I
MkA≤
(k=1 ... N, but k ≠ f)
Pole line feeder line: I
MkA≤
(k=n+ ... N, but k ≠ f)
Confirm that f is a fault wire, all the other k ≠ f are non-fault wire.Wherein: N is the feeder line number, and n is the cable number.
Output module: directly print the route selection result/show, and deliver to fault locator or module to the route selection result.
Claims (10)
1. the method for discrimination of a single-phase grounded malfunction in grounded system of low current line may further comprise the steps:
1) with the travelling wave current signal of all feeder lines of travelling wave current sensor measurement small current neutral grounding system;
2) the travelling wave current signal is delivered to that signal processing circuit decays, shaping is handled with coaxial cable for high frequency symmetry transmission;
3) the output signal of signal processing circuit is delivered to amplitude discrimination circuit and is carried out amplitude discrimination after photoelectric isolating circuit is isolated, and obtains the travelling wave current amplitude of all feeder lines;
4) if the discrimination module size of the travelling wave current amplitude of all feeder lines relatively is I
Mf＞I
Mk, k=1 ... N, N are the sum of feeder line, k ≠ f, and then f is a fault wire.
2. the method for discrimination of single-phase grounded malfunction in grounded system of low current line according to claim 1 uses in the said step 1) that zero sequence CT obtains zero sequence travelling wave current on the feeder line in the feeder line screen cabinet.
3. the method for discrimination of single-phase grounded malfunction in grounded system of low current line according to claim 1, use in the said step 1) A and C in the feeder line screen cabinet mutually CT obtain the reach the standard grade travelling wave current signal of preface of feeder line.
4. according to the method for discrimination of claim 2 or 3 described single-phase grounded malfunction in grounded system of low current lines, adopt the travelling wave current converter unit to be connected on CT Secondary Winding line end in the said step 1) and obtain.
5. the method for discrimination of single-phase grounded malfunction in grounded system of low current line according to claim 1 uses hood type travelling wave current sensor in the said step 1), obtain zero sequence or line preface travelling wave current signal.
6. the method for discrimination of single-phase grounded malfunction in grounded system of low current line according to claim 1, in the said step 4), N bar feeder line is cable entirely or is pole line entirely, if I
Mk≤
K=1 ... N, k ≠ f, judgement f is a fault wire, all the other are non-fault wire.
7. the method for discrimination of single-phase grounded malfunction in grounded system of low current line according to claim 1, in the said step 4), in the N bar mixing feeder line, n bar cable wherein, (N-n) bar pole line, if
Cable feeder line: I
Mk≤
I
MfK=1... n, k ≠ f; Or pole line feeder line: I
Mk≤
K=n+1... N, k ≠ f; Judgement f is a fault wire.
8. the discriminating gear of a single-phase grounded malfunction in grounded system of low current line; It is characterized in that: comprise travelling wave current sensor, coaxial cable for high frequency, signal processing circuit, photoelectric isolating circuit, amplitude discrimination circuit, discrimination module, said travelling wave current sensor obtains the travelling wave current signal of all feeder lines of small current neutral grounding system; With coaxial cable for high frequency symmetry transmission the travelling wave current signal of travelling wave current sensor is delivered to that signal processing circuit decays, shaping is handled; The output signal of signal processing circuit is delivered to photoelectric isolating circuit, after photoelectric isolating circuit is isolated, delivers to amplitude discrimination circuit and carries out amplitude discrimination, the travelling wave current amplitude of all feeder lines of amplitude discrimination circuit output; Discrimination module is the size of the travelling wave current amplitude of all feeder lines relatively, according to ordering relatively: I
Mf＞I
MkOr relatively according to definite value:
Cable feeder line: I
Mk≤
I
Mf(k=1... n, k ≠ f);
Pole line feeder line: I
Mk≤
(k=n+1... N, k ≠ f);
Judgement f is a fault feeder, and all the other are non-fault wire;
I in the following formula
MfBe the fault traveling wave current amplitude on the fault wire f, I
Mk(k=1 ... N, but k ≠ f) is a fault traveling wave current amplitude on the non-fault wire.
9. the discriminating gear of single-phase grounded malfunction in grounded system of low current line according to claim 8; It is characterized in that: said travelling wave current sensor adopts hood type travelling wave current sensor; Be two semi-rings of symmetry, the anchor ear mode is installed in the zero-sequence fault travelling wave current that accurately obtains feeder line on the feeder cable.
10. the discriminating gear of single-phase grounded malfunction in grounded system of low current line according to claim 8 is characterized in that: said travelling wave current sensor utilizes A in the feeder line cabinet, C two phase CT accurately to obtain the line preface fault traveling wave electric current of feeder line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101988885A CN102830327A (en) | 2012-06-15 | 2012-06-15 | Judging method and device of single-phase grounding fault line of small-current grounding system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012101988885A CN102830327A (en) | 2012-06-15 | 2012-06-15 | Judging method and device of single-phase grounding fault line of small-current grounding system |
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| CN102830327A true CN102830327A (en) | 2012-12-19 |
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| CN2012101988885A Pending CN102830327A (en) | 2012-06-15 | 2012-06-15 | Judging method and device of single-phase grounding fault line of small-current grounding system |
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Cited By (4)
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| CN103278748A (en) * | 2013-06-05 | 2013-09-04 | 昆明理工大学 | Fault location method of power distribution network cable-wire combined circuit based on tested simulation |
| CN103293432A (en) * | 2013-05-19 | 2013-09-11 | 国家电网公司 | Single-phase high-impedance grounding fault recognition method of power transmission line |
| CN103683513A (en) * | 2013-12-25 | 2014-03-26 | 国家电网公司 | Small current grounding fault online information monitoring and controlling method and device |
| CN105203923A (en) * | 2015-09-18 | 2015-12-30 | 国家电网公司 | Power distribution network cable failure monitoring method based on traveling wave amplitude measure |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105203923B (en) * | 2015-09-18 | 2018-08-14 | 国家电网公司 | The cable faults of distribution network monitoring method estimated based on traveling wave amplitude |
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Inventor after: Zhou Yanling Inventor after: Chen Li Inventor after: Kuang Wenkai Inventor after: Yi Qi Inventor before: Zhou Yanling Inventor before: Chen Li Inventor before: Kuang Yuankai Inventor before: Yi Qi |
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Free format text: CORRECT: INVENTOR; FROM: ZHOU YANLING CHEN LI KUANG YUANKAI YI QI TO: ZHOU YANLING CHEN LI KUANG WENKAI YI QI |
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Application publication date: 20121219 |