CN102768325A - Fault location method for low-current grounding system - Google Patents
Fault location method for low-current grounding system Download PDFInfo
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- CN102768325A CN102768325A CN2012102158650A CN201210215865A CN102768325A CN 102768325 A CN102768325 A CN 102768325A CN 2012102158650 A CN2012102158650 A CN 2012102158650A CN 201210215865 A CN201210215865 A CN 201210215865A CN 102768325 A CN102768325 A CN 102768325A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
Abstract
The invention discloses a fault location method for a low-current grounding system in the technical field of power system fault location technology. The fault location method for the low-current grounding system includes measuring voltage and current at protection installation first; obtaining a fault point voltage expression; measuring current abrupt change of a capacitor; obtaining a relation expression of the current abrupt change and fault point voltage according to the abrupt change of the capacitor and the fault point voltage expression, and finally obtaining location of a ground fault. According to the characteristic that distribution lines distribute capacitive current, the location of the ground fault of the low-current grounding system is measured, the fault location can be determined in a short time after fault, power supply can be restored as soon as possible, and power supply reliability is improved.
Description
Technical field
The invention belongs to electric power system fault ranging technology field, relate in particular to a kind of low current neutral grounding system fault distance-finding method.
Background technology
Small current neutral grounding system line fault location is a century difficult problem; Because a large amount of distribution line in the system, the probability that earth fault takes place is very big, but up to the present can only accomplish correctly to select faulty line for small current neutral grounding system; Can't accomplish the correct measurement fault distance; This is because of the circuit for small current neutral grounding system in a single day earth fault to take place, and does not almost have fault current, and traditional Fault Locating Method can't be confirmed fault distance.This correctly searches the trouble spot just for the field operator, in time eliminates potential faults, improves power supply reliability and has increased very big difficulty.The hidden fault of sometimes searching a supply line possibly need several days time.
Summary of the invention
Can't confirm the deficiency of fault distance to mentioning existing low current grounding in the above-mentioned background technology, the present invention proposes a kind of low current neutral grounding system fault distance-finding method.
Technical scheme of the present invention is that a kind of low current neutral grounding system fault distance-finding method is characterized in that this method may further comprise the steps:
Step 1: the voltage and current of measuring the protection installation place;
Step 2: the voltage expression formula that on the basis of step 1, obtains the place, trouble spot;
Step 3: the jump-value of current of measuring electric capacity;
Step 4: according to the voltage expression formula at the jump-value of current of electric capacity and place, trouble spot, try to achieve the relational expression of the voltage of locating in jump-value of current and trouble spot, and then the fault distance when trying to achieve earth fault.
The voltage expression formula at place, said trouble spot is:
Wherein:
U
fVoltage for the place, trouble spot;
Fault distance when x is earth fault;
Z
1Be every kilometer positive sequence impedance;
K is the zero sequence compensation coefficient;
I
OBe zero-sequence current.
The relational expression of the voltage at said jump-value of current and place, trouble spot is:
Wherein:
Δ I
cJump-value of current for electric capacity;
Im () is the imaginary part of variable;
Re () is the real part of variable.
The computing formula of the fault distance during said earth fault is:
The present invention proposes a kind of low current neutral grounding system fault distance-finding method.Utilize the characteristics measured current earthed system earth fault distance of distribution line capacitance current, just can confirm fault distance in the time of after breaking down, extremely lacking, be beneficial to restore electricity as early as possible, improve power supply reliability.Test findings surface the inventive method has been eliminated the influence to ground distance protection of load current and stake resistance.
Description of drawings
Fig. 1 is a small current neutral grounding system ground path fault synoptic diagram.
Embodiment
Below in conjunction with accompanying drawing, preferred embodiment is elaborated.Should be emphasized that following explanation only is exemplary, rather than in order to limit scope of the present invention and application thereof.
The present invention relates to the method for small current neutral grounding system localization of fault in the field of power.Disclose earth fault positioning principle in a kind of small current neutral grounding system, fault distance is meant all that usually the protection installation place is to the distance between the trouble spot.Be that electric current and voltage amount measured place is to the distance between the trouble spot.When distribution line of small-current grounding system generation earth fault, the electric current of (as shown in Figure 1) protection installation place does
Voltage does
Fault distance during earth fault is that x, voltage are U
f, ground current is I
f, protection records the jump-value of current Δ I of electric capacity
CBecause be that fault is always ohmic, so U is arranged
fAnd I
fSame-phase; Because Δ I
CAnd I
fThe phasing degree is identical, so draw U
fWith Δ I
CPhase angle is identical.
Δ I
CAnd U
fBecome plural form,, obtain Δ I because both phase angles are identical
CImaginary part and the ratio of real part equal U
fImaginary part and the ratio of real part, that is:
Calculate thus:
Because this equation itself is irrelevant with load current and stake resistance, the fault localization element when therefore can be used as distribution line of small-current grounding system generation earth fault.Theoretical analysis and simulation result show that all the principle of carrying has very high practicality and computational accuracy.
As shown in Figure 1, so do not have the traditional method of fault current can not the correct measurement fault distance for small current neutral grounding system trouble spot when earth fault takes place.But the capacitance current of total system can be flow through in the trouble spot, utilizes the synchronous principle of fault point voltage and electric current, can correct measurement low current neutral grounding system fault distance.The distribution line failure distance measuring equipment obtains the electric current and voltage instantaneous value to the voltage current waveform sampling of mutual inductor according to the present invention, obtains through fourier algorithm
Δ I
C, I
ODeng the phasor form; Because I
f, U
f, Δ I
CPhase angle identical, obtain and the irrelevant fault distance of load current and stake resistance:
Symbol in below discussing uses as follows: current transformer (being called for short TA, as follows) and voltage transformer (VT) (being called for short TV, as follows).
At first protect according to the TA of protection installation place and the instantaneous value that TV records electric current and voltage.
Secondly obtain the phasor form of each electric parameters through fourier algorithm, utilize following formula to obtain:
The above; Be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technician who is familiar with the present technique field is in the technical scope that the present invention discloses; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.
Claims (4)
1. low current neutral grounding system fault distance-finding method is characterized in that this method may further comprise the steps:
Step 1: the voltage and current of measuring the protection installation place;
Step 2: the voltage expression formula that on the basis of step 1, obtains the place, trouble spot;
Step 3: the jump-value of current of measuring electric capacity;
Step 4: according to the voltage expression formula at the jump-value of current of electric capacity and place, trouble spot, try to achieve the relational expression of the voltage of locating in jump-value of current and trouble spot, and then the fault distance when trying to achieve earth fault.
2. a kind of low current neutral grounding system fault distance-finding method according to claim 1 is characterized in that the voltage expression formula at place, said trouble spot is:
Wherein:
U
fVoltage for the place, trouble spot;
Fault distance when x is earth fault;
Z
1Be every kilometer positive sequence impedance;
K is the zero sequence compensation coefficient;
I
OBe zero-sequence current.
3. a kind of low current neutral grounding system fault distance-finding method according to claim 1 is characterized in that the relational expression of the voltage at said jump-value of current and trouble spot place is:
Wherein:
Δ I
cJump-value of current for electric capacity;
Im () is the imaginary part of variable;
Re () is the real part of variable.
4. a kind of low current neutral grounding system fault distance-finding method according to claim 2, the computing formula of the fault distance when it is characterized in that said earth fault is:
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210215865.0A CN102768325B (en) | 2012-06-26 | 2012-06-26 | Fault location method for low-current grounding system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210215865.0A CN102768325B (en) | 2012-06-26 | 2012-06-26 | Fault location method for low-current grounding system |
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| CN102768325A true CN102768325A (en) | 2012-11-07 |
| CN102768325B CN102768325B (en) | 2014-07-30 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103116114A (en) * | 2013-01-23 | 2013-05-22 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Fault location method and system under direct current deicing device earth wire deicing mode |
| CN103226175A (en) * | 2013-03-21 | 2013-07-31 | 江苏省电力公司泰州供电公司 | Method for achieving double-ended ranging by virtue of resistance characteristics of ground resistor |
| CN103245876A (en) * | 2013-04-15 | 2013-08-14 | 国家电网公司 | Method for realizing line interphase fault single-ended distance measurement by means of real part characteristics of voltage drop |
| CN103293439A (en) * | 2013-05-19 | 2013-09-11 | 国家电网公司 | Single-terminal distance measurement method for line single-phase earth faults based on distributed parameter measurement impedance amplitude characteristics |
| CN110470950A (en) * | 2019-08-16 | 2019-11-19 | 深圳供电局有限公司 | Fault positioning method for transmission line |
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| US20030155929A1 (en) * | 2002-02-20 | 2003-08-21 | Myoen-Song Choi | Method for detecting line-to-ground fault location in power network |
| CN101340086A (en) * | 2008-01-21 | 2009-01-07 | 孙嘉宁 | Single-phase grounding fault determining, protecting method and system of neutral-point uneffective earthed electric grid |
| CN101387682A (en) * | 2008-10-27 | 2009-03-18 | 清华大学 | Single-phase earth fault detecting method based on residual current harmonic component |
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2012
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| US20030155929A1 (en) * | 2002-02-20 | 2003-08-21 | Myoen-Song Choi | Method for detecting line-to-ground fault location in power network |
| CN101340086A (en) * | 2008-01-21 | 2009-01-07 | 孙嘉宁 | Single-phase grounding fault determining, protecting method and system of neutral-point uneffective earthed electric grid |
| CN101387682A (en) * | 2008-10-27 | 2009-03-18 | 清华大学 | Single-phase earth fault detecting method based on residual current harmonic component |
Non-Patent Citations (1)
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103116114A (en) * | 2013-01-23 | 2013-05-22 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Fault location method and system under direct current deicing device earth wire deicing mode |
| CN103116114B (en) * | 2013-01-23 | 2015-08-19 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Fault distance-finding method under a kind of DC de-icing device ground wire deicing pattern and system |
| CN103226175A (en) * | 2013-03-21 | 2013-07-31 | 江苏省电力公司泰州供电公司 | Method for achieving double-ended ranging by virtue of resistance characteristics of ground resistor |
| CN103245876A (en) * | 2013-04-15 | 2013-08-14 | 国家电网公司 | Method for realizing line interphase fault single-ended distance measurement by means of real part characteristics of voltage drop |
| CN103245876B (en) * | 2013-04-15 | 2015-08-26 | 国家电网公司 | Voltage drop real part characteristic is utilized to realize circuit inter-phase fault single-end ranging |
| CN103293439A (en) * | 2013-05-19 | 2013-09-11 | 国家电网公司 | Single-terminal distance measurement method for line single-phase earth faults based on distributed parameter measurement impedance amplitude characteristics |
| CN103293439B (en) * | 2013-05-19 | 2015-12-02 | 国家电网公司 | Based on distribution parameter measurement impedance magnitude characteristic line single-phase earth fault single-terminal location method |
| CN110470950A (en) * | 2019-08-16 | 2019-11-19 | 深圳供电局有限公司 | Fault positioning method for transmission line |
| CN110470950B (en) * | 2019-08-16 | 2021-07-16 | 深圳供电局有限公司 | Fault location method for power transmission line |
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| Publication number | Publication date |
|---|---|
| CN102768325B (en) | 2014-07-30 |
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Inventor after: Xu Zhenyu Inventor after: Gao Rui Inventor after: Zhang Jinhu Inventor after: Xu Tao Inventor after: Li Cheng Inventor after: Fan Zhengzhen Inventor after: Wang Pingping Inventor after: Su Zhipeng Inventor after: Yang Zheng Inventor after: Fu Jinfa Inventor before: Xu Zhenyu Inventor before: Li Cheng Inventor before: Fan Zhengzhen Inventor before: Wang Pingping Inventor before: Su Zhipeng Inventor before: Yang Zheng Inventor before: Fu Jinfa Inventor before: Gao Rui |
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Free format text: CORRECT: INVENTOR; FROM: XU ZHENYU LI CHENG FAN ZHENGZHEN WANG PINGPING SU ZHIPENG YANG ZHENG FU JINFA GAO RUI TO: XU ZHENYU ZHANG JINHU XU TAO LI CHENG FAN ZHENGZHEN WANG PINGPING SU ZHIPENG YANG ZHENG FU JINFA GAO RUI |
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Granted publication date: 20140730 Termination date: 20170626 |