CN102332707B - Earth fault signal measuring method and protective device for ungrounded system - Google Patents
Earth fault signal measuring method and protective device for ungrounded system Download PDFInfo
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- CN102332707B CN102332707B CN201110151217.9A CN201110151217A CN102332707B CN 102332707 B CN102332707 B CN 102332707B CN 201110151217 A CN201110151217 A CN 201110151217A CN 102332707 B CN102332707 B CN 102332707B
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Abstract
The invention discloses an earth fault signal measuring method and a protective device for an ungrounded system. According to the method, an outlet of a cable line and measuring points of fault signals are arranged at the end of a shield ground wire of a cable head, a special-purpose earth fault current lead is laid at the end, and a cross-core open current transformer and a special-purpose lightning arrester are installed; an outlet of an overhead line and measuring points of fault signals are arranged at underground below a path formed by No. 0 to No. 6 poles of the outlet, an earth electrode is buried in the underground, an earth current acquisition wire is laid to connect to the earth electrode, and a cross-core open current transformer and a special-purpose lightning arrester are installed. The protective device comprises a cable line single-phase ground protection unit, an overhead line single-phase ground protection unit, a ground protection current latching unit, a ground protection voltage latching unit, a digital analog converter and a display. The method and the protective device provided in the invention enable a line selection rate under the condition of a line earth fault to be improved and the fault to be dealt with rapidly.
Description
Technical field
The present invention relates to a kind of electric power system earth fault signal measurement method and protective device, be specially adapted to measurement and the protective device of the transmission lines earth fault signal of isolated neutral system.
Background technology
At present, in the electric line of electric power system different brackets, the following electric line of 35KV moves with small current neutral grounding (through grounding through arc) and earth-free mode conventionally, above-mentioned operational mode, single phase ground fault the line is busy the more than 80% of road rate of failure total amount, the electric line that earth-free mode is moved, occur after single phase ground fault, system failure phase voltage reduces, healthy phases voltage raises, though faulty line can move in short-term, but operating equipment is produced and threatened, because of not only one of electric line in transformer station, rules require find at short notice faulty line and process.
Because earth fault varies, the earth fault line selection mode adopting both at home and abroad is at present also different, application number 91103633.4, name is called " detection method of small current neutral grounding and device " patent, adopts the method Judging fault of more each outlet zero-sequence current and non-fault current; Application number 94106374.7, name is called " small current system individual event earthing protecting method and device " patent, adopts fast the relatively idle method Judging fault of Zero-pharse harmonic; Application number 00114452.9, name is called " earthing protection method for small current earthing system " patent, adopts and calculates each feeder line negative-sequence current variable quantity, according to negative-sequence current size of current, direction or energy function, carrys out Judging fault; The fault-signal source of above-mentioned each method is all selected from public power current transformer and the voltage transformer of each outlet, and the resolution of Judging fault circuit is low.
The present invention arranges special fault-signal measurement point and measuring component to every transmission line, has designed new measuring circuit and protective device, has improved line fault resolution.
Summary of the invention
The object of this invention is to provide a kind of isolated neutral system earth fault signal measurement new method and protective device; by ground signalling being measured to selection, the design of measuring circuit and the Construction designing of protective device a little; make the formation of fault characteristic signals source and protective device become possibility; in order to achieve the above object, taked following method of measurement:
1, the cable line outlet to transformer station, fault-signal measures the bonding thread end that is a little selected in cable end, in end, lay a Special grounding fault current lead-in wire (9), at a first punching opening current transformer (6) of the upper installation of current feed (9), the first punching opening current transformer (6) side connects first Special lightning arrester (8);
2, the overhead transmission line outlet to transformer station, it is underground that another fault-signal measures the path of No. 0 bar to 6 bar that is a little selected in outlet, at a grounding electrode of embedded underground (15), along going out thread path, lay an earth current collection line (14) being connected with grounding electrode (15), earth current gathers a second punching opening current transformer (12) of the upper installation of line (14), the second punching opening current transformer (12) side connects second Special lightning arrester (13), and grounding electrode and earth connection are through preservative treatment;
3, the first punching opening current transformer (6) and the upper secondary singal gathering of the second punching opening current transformer (12) are delivered to checkout gear, as the signal source of fault distinguishing;
4, a 3rd punching opening current transformer (5) is installed on the neutral point of substation grounding transformer or the earth connection of arc suppression coil (4), as the reliable signal source of judging line-to-ground, the 3rd punching opening current transformer (5) side connects the 3rd Special lightning arrester.
Implement this method and require each road earth current to gather line, every grounding transformer neutral point, the high-pressure side neutral ground line of bus-bar potential transformer, is all connected in the 10KV of transformer station, 35KV switch gear room on main grounding grid reliably.
For realizing the inventive method; specialized designs a kind of protective device; protective device consists of cable line one-phase ground protection unit (17), overhead transmission line one-phase ground protection unit (18), ground protection current interlock unit (19), ground protection voltage blocking unit (20), digital to analog converter (21) and display (22), and each cellular construction is as follows:
1, cable line one-phase ground protection unit (17) include current relay, earth current display element A, in its protection major loop, series connection access has current interlock contact and a voltage blocking contact, in its protection major loop, the circuit part of access in parallel is: instantaneous operation time control components SJ moves in signal circuit section after connecting with signal controlling element XJ, and time-delay action control element SJ1 moves in trip circuit part after connecting with switch trip control element TQ;
2, the structure of overhead transmission line one-phase ground protection unit (18) is identical with cable line one-phase ground protection unit (17); Ground protection current interlock unit (19) is constituted by total earth current transmitter and earth current display element A two parts; Ground protection voltage blocking unit (20) shows that by voltage transmitter, insulation voltage data element V two parts constitute.
The source of the input signal of protective device is: the current relay input signal of cable line one-phase ground protection unit (17) is from the first punching opening current transformer (6), the input signal of the current transducer of overhead transmission line one-phase ground protection unit (18) is from punching the second opening current transformer (12), the input signal of total earth current transmitter of ground protection current interlock unit (19) is from the 3rd opening current transformer (5), the input signal of ground protection voltage blocking unit (20) is from bus-bar potential transformer secondary insulating supervision open delta coil (11), the output signal of cable line one-phase ground protection unit (17), overhead transmission line one-phase ground protection unit (18), ground protection current interlock unit (19) and ground protection voltage blocking unit (20) is delivered to display (22) after digital to analog converter (21).
New method of measurement and protective device are owing to having adopted special fault-signal measurement point; with the technology now extensively adopting compared with device; improved the discrimination of fault, made protective device can select reliably faulty line and move in tripping operation and send fault-signal.
Accompanying drawing explanation
Fig. 1 isolated neutral system earth fault signal measurement method and protective device key wiring diagram
In the drawings, the main transformer of isolated neutral system is 1, ground network 7, the first Special lightning arrester 8, cable outlet Special grounding fault current lead-in wire 9, user's ground network 10, the open delta voltage transmitter 11 of bus-bar potential transformer, the second punching opening current transformer 12, the second Special lightning arrester 13, earth current gather line 14, grounding electrode 15, overhead transmission line 16 in cable line 2, bus-bar potential transformer 3, grounding transformer or arc suppression coil 4, the 3rd punching opening current transformer 5, the first punching opening current transformer 6, switch gear room.
Fig. 2 isolated neutral system earth-fault protection block diagram
In the drawings, cable line one-phase ground protection unit be 17, overhead transmission line one-phase ground protection unit 18, ground protection current interlock unit 19, ground protection voltage blocking unit 20, digital to analog converter 21 and display 22.
Embodiment
Below in conjunction with accompanying drawing, the structure of specific embodiment of the invention method and apparatus is described in further detail.
Fig. 1 has provided isolated neutral system earth fault signal measurement method and protective device key wiring diagram, and for cable outlet and every overhead transmission line outlet of transformer station, the method for measuring fault-signal that adopts is respectively:
1, the cable line outlet to transformer station, fault-signal measures the bonding thread end that is a little selected in house cable head, in end, lay a Special grounding fault current lead-in wire 9, on Special grounding fault current lead-in wire 9, a first punching opening current transformer 6 is installed, in order to prevent lightning surge intrusion, on the first punching opening current transformer 6 sides, connect first Special lightning arrester 8.
2, the overhead transmission line outlet to transformer station, it is underground that another fault-signal measures the path of No. 0 bar to 6 bar that is a little selected in outlet, select a solution space, and at grounding electrode 15 of embedded underground, along going out thread path, lay an earth current collection line 14 being connected with grounding electrode 15, in the proper site of earth current collection line 14, a second punching opening current transformer 12 is installed, and connecing second Special lightning arrester 13 on the second punching opening current transformer 12 sides, grounding electrode and earth connection need to pass through preservative treatment.
3, the secondary singal gathering on the first punching opening current transformer 6 and the second punching opening current transformer 12 is delivered to checkout gear, as the signal source of fault distinguishing.
4, a 3rd punching opening current transformer 5 is installed on the neutral point of substation grounding transformer or the neutral ground line of arc suppression coil 4, as the reliable signal source of judging line-to-ground, the 3rd punching opening current transformer 5 sides connect the 3rd Special lightning arrester.
This method requires each road earth current to gather line, every grounding transformer neutral point, and the high-pressure side neutral ground line of bus-bar potential transformer all must be connected in the 10KV of transformer station, 35KV switch gear room on main grounding grid reliably.
Fig. 2 has provided isolated neutral system earth-fault protection block diagram; this protective device consists of cable line one-phase ground protection unit 17, overhead transmission line one-phase ground protection unit 18, ground protection current interlock unit 19, ground protection voltage blocking unit 20, digital to analog converter 21 and display 22, and each cellular construction of device is as follows:
1, cable line one-phase ground protection unit 17 includes current relay; earth current display element A; in its protection major loop, series connection access has current interlock contact and a voltage blocking contact; in its protection major loop, the circuit part of access in parallel is: instantaneous operation time control components SJ moves in signal circuit section after connecting with signal controlling element XJ, and time-delay action control element SJ1 moves in trip circuit part after connecting with switch trip control element TQ.
2, the structure of overhead transmission line one-phase ground protection unit 18 is identical with cable line one-phase ground protection unit 17; Ground protection current interlock unit 19 is constituted by total earth current transmitter and earth current display element A two parts; Ground protection voltage blocking unit 20 shows that by voltage transmitter, insulation voltage data element V two parts constitute.
The source of the input signal of protective device is: the input signal of the current relay of cable line one-phase ground protection unit 17 is from the first punching opening current transformer 6, the input signal of the current transducer of overhead transmission line one-phase ground protection unit 18 is from the second punching opening current transformer 12, the input signal of total earth current transmitter of ground protection current interlock unit 19 is from the 3rd opening current transformer 5, and the input signal of ground protection voltage blocking unit 20 is from bus-bar potential transformer secondary insulating supervision open delta coil 11; The output signal of cable line one-phase ground protection unit 17, overhead transmission line one-phase ground protection unit 18, ground protection current interlock unit 19 and ground protection voltage blocking unit 20 is delivered to display 22 after digital to analog converter 21.
Protective device action specification is as follows:
1,, when cable line generation single phase ground fault, the earth fault current signal in user's ground network is back to the neutral point of grounding transformer 4 by cable screening wire.The first punching opening current transformer 6 on cable shield earth connection produces signal, and the current relay LJ of cable line one-phase ground protection unit 17 starts.
2, high-tension overhead line generation single phase ground fault, line-to-ground electric current gathers line 14 and is back to the neutral point of grounding transformer 4 along the grounding electrode 15 of overhead transmission line embedded underground and earth current.On circuit, the second punching opening current transformer 12 produces signal, and the current transducer LJ of overhead transmission line one-phase ground protection unit 18 starts.
3,, in cable line and overhead transmission line generation earth fault, the 3rd punching opening current transformer 5 that grounding transformer neutral point is installed starts simultaneously, LJ Z junction closure.The open delta voltage transmitter voltage of bus-bar potential transformer raises, and starting YJ contact is through time component SJ1 timing closing, and trigger circuit ground protection unit 17,18 completes the ground fault circuit interrupteur work of cutting off.
4, circuit generation transient earthing fault, circuit the first punching opening current transformer 6, the second punching opening current transformer 12, the 3rd punching opening current transformer 5 that grounding transformer neutral point is installed, insulating monitoring open delta voltage YJ contact, time SJ contact is simultaneously closed, sends concrete certain circuit transient earthing signal.
5, circuit transient earthing YJ voltage blocking contact and time SJ1 contact are not closed, are failure to actuate in trip protection loop.
6, circuit generation permanent earth fault, LJ, LJZ, voltage blocking contact YJ and time SJ-1 contact are simultaneously closed, and start protection trip(ping) circuit completes disengagement failure line work.
7, the normal operating leakage current of cable line and overhead transmission line and capacitance current, show on screen through current transducer analog-to-digital conversion.
The concrete wiring of this protective device is carried out according to the wiring requirement of relaying protection and rules; the element such as selected electric, electronics, electrical equipment in device; all select electrician's components and parts general in international standard, the concrete wiring of each element is carried out by element requirement, at this, does not elaborate.
Claims (4)
1. an isolated neutral system earth fault signal measurement method, is characterized in that, described method of measurement comprises the following steps:
(1) the cable line outlet to transformer station, fault-signal measures the bonding thread end that is a little selected in cable end, in end, lay a Special grounding fault current lead-in wire (9), at a first punching opening current transformer (6) of the upper installation of current feed (9), the first punching opening current transformer (6) side connects first Special lightning arrester (8);
(2) the overhead transmission line outlet to transformer station, it is underground that another fault-signal measures the path of No. 0 bar to 6 bar that is a little selected in outlet, at a grounding electrode of embedded underground (15), along going out thread path, lay an earth current collection line (14) being connected with grounding electrode (15), earth current gathers a second punching opening current transformer (12) of the upper installation of line (14), the second punching opening current transformer (12) side connects second Special lightning arrester (13), and grounding electrode and earth connection are through preservative treatment;
(3) the first punching opening current transformer (6) and the upper secondary singal gathering of the second punching opening current transformer (12) are delivered to checkout gear, as the signal source of fault distinguishing;
(4) a 3rd punching opening current transformer (5) is installed on the neutral point of substation grounding transformer or the earth connection of arc suppression coil (4), as the reliable signal source of judging line-to-ground, the 3rd punching opening current transformer (5) side connects the 3rd Special lightning arrester.
2. isolated neutral system earth fault signal measurement method according to claim 1, it is characterized in that: each road earth current gathers line, every grounding transformer neutral point, the high-pressure side neutral ground line of bus-bar potential transformer, is all connected in the 10KV of transformer station, 35KV switch gear room on main grounding grid reliably.
3. the protective device of isolated neutral system earth fault signal measurement method according to claim 1; it is characterized in that: protective device consists of cable line one-phase ground protection unit (17), overhead transmission line one-phase ground protection unit (18), ground protection current interlock unit (19), ground protection voltage blocking unit (20), digital to analog converter (21) and display (22), and each cellular construction is as follows:
(1) cable line one-phase ground protection unit (17) include current relay, earth current display element A, in its protection major loop, series connection access has current interlock contact and a voltage blocking contact, in its protection major loop, the circuit part of access in parallel is: instantaneous operation time control components SJ moves in signal circuit section after connecting with signal controlling element XJ, and time-delay action control element SJ1 moves in trip circuit part after connecting with switch trip control element TQ;
(2) structure of overhead transmission line one-phase ground protection unit (18) is identical with cable line one-phase ground protection unit (17); Ground protection current interlock unit (19) is constituted by total earth current transmitter and earth current display element A two parts; Ground protection voltage blocking unit (20) shows that by voltage transmitter, insulation voltage data element V two parts constitute.
4. protective device according to claim 3, it is characterized in that: the input signal of the current relay of cable line one-phase ground protection unit (17) is from the first punching opening current transformer (6), the input signal of the current transducer of overhead transmission line one-phase ground protection unit (18) is from punching the second opening current transformer (12), the input signal of total earth current transmitter of ground protection current interlock unit (19) is from the 3rd opening current transformer (5), the input signal of ground protection voltage blocking unit (20) is from bus-bar potential transformer secondary insulating supervision open delta coil (11), the output signal of cable line one-phase ground protection unit (17), overhead transmission line one-phase ground protection unit (18), ground protection current interlock unit (19) and ground protection voltage blocking unit (20) is delivered to display (22) after digital to analog converter (21).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201110151217.9A CN102332707B (en) | 2011-06-08 | 2011-06-08 | Earth fault signal measuring method and protective device for ungrounded system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110151217.9A CN102332707B (en) | 2011-06-08 | 2011-06-08 | Earth fault signal measuring method and protective device for ungrounded system |
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| Publication Number | Publication Date |
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| CN102332707A CN102332707A (en) | 2012-01-25 |
| CN102332707B true CN102332707B (en) | 2014-04-16 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106329509B (en) * | 2015-06-18 | 2019-09-13 | 上海金艺检测技术有限公司 | The small current earthing wire-selecting of neutral point of electric network isolated neutral system protects system |
| DE102015122128A1 (en) * | 2015-12-17 | 2017-06-22 | Bender Gmbh & Co. Kg | Method and apparatus for advanced isolation fault detection in an ungrounded power system and method for condition monitoring of the power system |
| CN108718076A (en) * | 2018-07-02 | 2018-10-30 | 润电新能源（英德）有限公司 | Ground connection becomes relay protecting method and ground connection becomes protective device |
| CN108957232A (en) * | 2018-07-18 | 2018-12-07 | 杭州新融方科技有限公司 | A kind of distribution net work earthing fault detection processing and its operating method |
| CN110850238A (en) * | 2019-12-18 | 2020-02-28 | 济南泰景电力技术有限公司 | Power cable leakage detection method and system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1355585A (en) * | 2000-10-20 | 2002-06-26 | 施魏策尔工程实验公司 | Failure type selecting system for identificating failure in electric system |
| CN2849736Y (en) * | 2005-08-02 | 2006-12-20 | 高政 | System for detecting large grounding network of power plant and transformer substation |
| CN101246199A (en) * | 2007-02-14 | 2008-08-20 | 高政 | Method and device for wirelessly detecting grounded screen fault |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US7149066B2 (en) * | 2003-10-07 | 2006-12-12 | Eaton Corporation | Fault detector for two line power distribution system and protection apparatus incorporating the same |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1355585A (en) * | 2000-10-20 | 2002-06-26 | 施魏策尔工程实验公司 | Failure type selecting system for identificating failure in electric system |
| CN2849736Y (en) * | 2005-08-02 | 2006-12-20 | 高政 | System for detecting large grounding network of power plant and transformer substation |
| CN101246199A (en) * | 2007-02-14 | 2008-08-20 | 高政 | Method and device for wirelessly detecting grounded screen fault |
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