CN104049176B - One-phase earthing failure in electric distribution network recognition methods - Google Patents
One-phase earthing failure in electric distribution network recognition methods Download PDFInfo
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- CN104049176B CN104049176B CN201410244692.4A CN201410244692A CN104049176B CN 104049176 B CN104049176 B CN 104049176B CN 201410244692 A CN201410244692 A CN 201410244692A CN 104049176 B CN104049176 B CN 104049176B
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Abstract
A kind of one-phase earthing failure in electric distribution network recognition methods, relates to distribution network technology field, and solved is the technical problem reducing singlephase earth fault identification cost.First each outlet according to power distribution network bus of the method is at current time and the negative sequence current value of previous moment, calculate the negative-sequence current change absolute value of maximum, and the negative-sequence current difference value of minimum, in conjunction with power distribution network bus in the zero-sequence current value of current time and previous moment, further calculate fault index, judge whether power distribution network occurs singlephase earth fault further according to fault index.The method that the present invention provides, it is adaptable to the identification of one-phase earthing failure in electric distribution network.
Description
Technical field
The present invention relates to distribution network technology, particularly relate to the technology of a kind of one-phase earthing failure in electric distribution network recognition methods.
Background technology
Power distribution network uses non-effective earthing mode to run mostly, when power distribution network occurs singlephase earth fault, due to
Short circuit current is through grounding through arc, and its earth current is the least, and power distribution network is three when properly functioning
Phase asymmetric operating, also exists negative-sequence current, and therefore the singlephase earth fault of power distribution network is often difficult to, often
Need to configure special detection equipment separately to assist in identifying, thus add the cost of power distribution network.
Summary of the invention
For defect present in above-mentioned prior art, the technical problem to be solved is to provide and a kind of can drop
Low singlephase earth fault identification cost, and the one-phase earthing failure in electric distribution network recognition methods that recognition accuracy is high.
In order to solve above-mentioned technical problem, a kind of one-phase earthing failure in electric distribution network recognition methods provided by the present invention,
It is characterized in that, specifically comprise the following steps that
1) set current time as T, obtain power distribution network bus in T moment and the zero-sequence current value of T-Δ t, and
Obtain each outlet of power distribution network bus at T moment and the negative sequence current value of T-Δ t；
Wherein, Δ t is time constant set in advance；
2) each outlet of calculating power distribution network bus is from the negative-sequence current change absolute value of T-Δ t to T moment,
Specific formula for calculation is:
Df [j]=| I2 [j, 0]-I2 [j ,-t] |；
In formula, Df [j] is that the jth outlet of power distribution network bus changes from the negative-sequence current of T-Δ t to T moment
Absolute value, I2 [j, 0] is the jth outlet negative sequence current value in the T moment of power distribution network bus, and I2 [j ,-t] is
The jth outlet of power distribution network bus is at the negative sequence current value of T-Δ t；
3) according to the result of calculation of step 2, the negative-sequence current change absolute value of power distribution network each outlet of bus is obtained
Maximum, and this negative-sequence current change absolute value is designated as Dfmax, it is Dfmax by negative-sequence current change absolute value
Outlet be set as k outlet；
4) in the outlet of establishing electrical network bus, other outlet in addition to k outlet is non-k outlet, calculates each
The negative-sequence current difference value of individual non-k outlet, specific formula for calculation is:
SDf [i]=| λ × Df [i] Dfmax |；
In formula, SDf [i] is the negative-sequence current difference value of i-th non-k outlet, Df [i] be i-th non-k outlet from
T-Δ t is to the negative-sequence current change absolute value in T moment, and λ is sharing of load coefficient, and the representative value of λ is 0.85；
5) according to the result of calculation of step 4, the minimum of a value in the negative-sequence current difference value of each non-k outlet is obtained,
And this negative-sequence current difference value is designated as SDfmin；
6) calculating fault index, specific formula for calculation is:
β=β 1+ β 2+ β 3；
β 1=| Dfmax SDfmin |/Dfmax；
β 2=SDfmin/Dfmax；
β 3=I1 [-t]/I1 [0]；
In formula, β is fault index, and I1 [0] is the power distribution network bus zero-sequence current value in the T moment, and I1 [-t] is for joining
Electrical network bus is in the zero-sequence current value of T-Δ t；
7) failure judgement index, if there being β < ε, then generation singlephase earth fault in judgement power distribution network, otherwise then
Judge power distribution network does not occurs singlephase earth fault；
Wherein, ε is constant.
Further, the value of Δ t is 1 minute.
Further, the value of ε is 0.2.
The one-phase earthing failure in electric distribution network recognition methods that the present invention provides, utilizes the existing resource of power distribution network, according to joining
The zero-sequence current history value of electrical network bus and the negative-sequence current history value of each outlet, the zero-sequence current in conjunction with bus is worked as
The negative-sequence current currency of front value and each outlet, is identified one-phase earthing failure in electric distribution network, can quickly know
Do not go out the singlephase earth fault in power distribution network, and recognition accuracy is high, is easily achieved in engineering, it is not necessary to increase volume
Outer investment, can reduce singlephase earth fault identification cost.
Detailed description of the invention
Below in conjunction with specific embodiment, technical scheme is described in further detail, but the present embodiment is not
For limiting the present invention, the analog structure of every employing present invention and similar change thereof, the guarantor of the present invention all should be listed in
Protect scope.
A kind of one-phase earthing failure in electric distribution network recognition methods that the embodiment of the present invention is provided, it is characterised in that concrete
Step is as follows:
1) set current time as T, obtain power distribution network bus in T moment and the zero-sequence current value of T-Δ t, and
Obtain each outlet of power distribution network bus at T moment and the negative sequence current value of T-Δ t；
Wherein, Δ t is time constant set in advance, and the representative value of Δ t is 1 minute；
2) each outlet of calculating power distribution network bus is from the negative-sequence current change absolute value of T-Δ t to T moment,
Specific formula for calculation is:
Df [j]=| I2 [j, 0]-I2 [j ,-t] |；
In formula, Df [j] is that the jth outlet of power distribution network bus changes from the negative-sequence current of T-Δ t to T moment
Absolute value, I2 [j, 0] is the jth outlet negative sequence current value in the T moment of power distribution network bus, and I2 [j ,-t] is
The jth outlet of power distribution network bus is at the negative sequence current value of T-Δ t；
3) according to the result of calculation of step 2, the negative-sequence current change absolute value of power distribution network each outlet of bus is obtained
Maximum, and this negative-sequence current change absolute value is designated as Dfmax, it is Dfmax by negative-sequence current change absolute value
Outlet be set as k outlet；
4) in the outlet of establishing electrical network bus, other outlet in addition to k outlet is non-k outlet, calculates each
The negative-sequence current difference value of individual non-k outlet, specific formula for calculation is:
SDf [i]=| λ × Df [i] Dfmax |；
In formula, SDf [i] is the negative-sequence current difference value of i-th non-k outlet, Df [i] be i-th non-k outlet from
T-Δ t is to the negative-sequence current change absolute value in T moment, and λ is sharing of load coefficient, and the representative value of λ is 0.85；
5) according to the result of calculation of step 4, the minimum of a value in the negative-sequence current difference value of each non-k outlet is obtained,
And this negative-sequence current difference value is designated as SDfmin；
6) calculating fault index, specific formula for calculation is:
β=β 1+ β 2+ β 3；
β 1=| Dfmax SDfmin |/Dfmax；
β 2=SDfmin/Dfmax；
β 3=I1 [-t]/I1 [0]；
In formula, β is fault index, and I1 [0] is the power distribution network bus zero-sequence current value in the T moment, and I1 [-t] is for joining
Electrical network bus is in the zero-sequence current value of T-Δ t；
7) failure judgement index, if there being β < ε, then generation singlephase earth fault in judgement power distribution network, otherwise then
Judge power distribution network does not occurs singlephase earth fault；
Wherein, ε is constant, and the representative value of ε is 0.2.
In the embodiment of the present invention, the zero-sequence current value of power distribution network bus, and the negative phase-sequence of each outlet of power distribution network bus
Current value, all can utilize existing electrical energy management subsystem in power system to obtain.
Claims (3)
1. an one-phase earthing failure in electric distribution network recognition methods, it is characterised in that specifically comprise the following steps that
1) set current time as T, obtain power distribution network bus in T moment and the zero-sequence current value of T-Δ t, and obtain each outlet of power distribution network bus at T moment and the negative sequence current value of T-Δ t；
Wherein, Δ t is time constant set in advance；
2) each outlet of calculating power distribution network bus is from the negative-sequence current change absolute value of T-Δ t to T moment, and specific formula for calculation is:
Df[j] =| I2[j,0] - I2[j,-t] |；
In formula, Df [j] is the jth outlet negative-sequence current change absolute value from T-Δ t to T moment of power distribution network bus, I2 [j, 0] it is the jth outlet negative sequence current value in the T moment of power distribution network bus, I2 [j ,-t] is the jth outlet negative sequence current value in T-Δ t of power distribution network bus；
3) according to the result of calculation of step 2, obtain the maximum of the negative-sequence current change absolute value of power distribution network each outlet of bus, and the maximum of this negative-sequence current change absolute value is designated as Dfmax, the outlet that negative-sequence current change absolute value is Dfmax is set as k outlet；
4) in the outlet of establishing electrical network bus, other outlet in addition to k outlet is non-k outlet, calculates the negative-sequence current difference value of each non-k outlet, and specific formula for calculation is:
SDf[i] =| λ×Df[i]
– Dfmax
|；
In formula, SDf [i] is the negative-sequence current difference value of i-th non-k outlet, and Df [i] is the i-th non-k outlet negative-sequence current change absolute value from T-Δ t to T moment, and λ is sharing of load coefficient, and the representative value of λ is 0.85；
5) according to the result of calculation of step 4, obtain the minimum of a value in the negative-sequence current difference value of each non-k outlet, and the minimum of a value of this negative-sequence current difference value is designated as SDfmin；
6) calculating fault index, specific formula for calculation is:
ß = ß1 + ß2
+ ß3；
ß1 = | Dfmax – SDfmin | / Dfmax；
ß2 = SDfmin / Dfmax；
ß3 = I1[-t]
/ I1[0]；
In formula, for fault index, I1 [0] is the power distribution network bus zero-sequence current value in the T moment, and I1 [-t] is the power distribution network bus zero-sequence current value in T-Δ t；
7) failure judgement index, if had, < ε then judges to occur in power distribution network singlephase earth fault, otherwise then judges, in power distribution network, singlephase earth fault does not occurs；
Wherein, ε is constant.
One-phase earthing failure in electric distribution network recognition methods the most according to claim 1, it is characterised in that: the value of Δ t is 1 minute.
One-phase earthing failure in electric distribution network recognition methods the most according to claim 1, it is characterised in that: the value of ε is 0.2.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995024014A2 (en) * | 1994-02-28 | 1995-09-08 | Abb Power T & D Company Inc. | One-terminal data fault location system |
| CN1282876A (en) * | 2000-09-15 | 2001-02-07 | 清华大学 | Method and equipment for positioning failure point on electric power transmission line |
| CN103063984A (en) * | 2012-12-20 | 2013-04-24 | 北京交通大学 | Power distribution network single-phase earth fault line selection method based on line double-terminal negative sequence current |
| CN103293442A (en) * | 2013-05-19 | 2013-09-11 | 国家电网公司 | Line single-phase earth fault single-terminal location method implemented by aid of zero-sequence voltage distribution characteristics |
-
2014
- 2014-06-04 CN CN201410244692.4A patent/CN104049176B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995024014A2 (en) * | 1994-02-28 | 1995-09-08 | Abb Power T & D Company Inc. | One-terminal data fault location system |
| CN1282876A (en) * | 2000-09-15 | 2001-02-07 | 清华大学 | Method and equipment for positioning failure point on electric power transmission line |
| CN103063984A (en) * | 2012-12-20 | 2013-04-24 | 北京交通大学 | Power distribution network single-phase earth fault line selection method based on line double-terminal negative sequence current |
| CN103293442A (en) * | 2013-05-19 | 2013-09-11 | 国家电网公司 | Line single-phase earth fault single-terminal location method implemented by aid of zero-sequence voltage distribution characteristics |
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Effective date of registration: 20190201 Address after: 200233 4, 14 building, 470 Guiping Road, Xuhui District, Shanghai. Co-patentee after: State Grid Shanghai Municipal Electric Power Company Patentee after: Shanghai Sunrise Power Technology Co., Ltd. Address before: 200233 4, 14 building, 470 Guiping Road, Xuhui District, Shanghai. Patentee before: Shanghai Sunrise Power Technology Co., Ltd. |
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