CN102332707A - 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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- CN102332707A CN102332707A CN201110151217A CN201110151217A CN102332707A CN 102332707 A CN102332707 A CN 102332707A CN 201110151217 A CN201110151217 A CN 201110151217A CN 201110151217 A CN201110151217 A CN 201110151217A CN 102332707 A CN102332707 A CN 102332707A
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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 the 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 usually; Above-mentioned operational mode, single phase ground fault the line is busy more than 80% of road rate of failure total amount, the electric line that earth-free mode is moved; After single phase ground fault took place, system failure phase voltage reduced, and non-fault phase voltage raises; Though faulty line can move in short-term; But operating equipment is produced threat, and because of not only one of electric line in the transformer station, rules require to find faulty line at short notice and handle.
Because earth fault varies; The earth fault line selection mode that adopts both at home and abroad at present also has nothing in common with each other; Application number 91103633.4, name is called " detection method of small current neutral grounding and device " patent, adopts the method that compares each outlet zero-sequence current and non-fault current to differentiate fault; Application number 94106374.7, name is called " small current system individual event earthing protecting method and device " patent, adopts fast the relatively idle method differentiation 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, differentiates fault according to negative-sequence current size of current, direction or energy function; The fault-signal source of above-mentioned each method all is selected from the public current transformer and the voltage transformer of each outlet, and the resolution of differentiating faulty line is low.
The present invention is provided with special-purpose 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 purpose of this invention is to provide a kind of isolated neutral system earth fault signal measurement new method and protective device; Through ground signalling being measured selection a little, the design of measuring circuit and the formation design of protective device; Make the formation of fault signature signal source and protective device become possibility; In order to achieve the above object, taked following method of measurement:
1, to the cable line outlet of transformer station; Fault-signal measures the bonding thread end that a little is selected in cable end; Lay a special-purpose earth fault current lead-in wire in the end; On the fault current lead-in wire, a punching opening current transformer is installed, punching opening current transformer next door connects a special-purpose lightning arrester;
2, to the overhead transmission line outlet of transformer station; It is underground to the path of No. 6 bars that fault-signal measures No. 0 of a little being selected in outlet; Bury a grounding electrode underground underground, lay an earth current that links to each other with earth electrode and gather line, a punching opening current transformer is installed on the current acquisition line along going out thread path; And by it, connecing a special-purpose lightning arrester, grounding electrode and earth connection need pass through preservative treatment;
3, the secondary singal of gathering on each punching opening current transformer is delivered to checkout gear, as the signal source of fault distinguishing;
4, a punching opening current transformer is installed on neutral point (or arc suppression coil) earth connection of substation grounding transformer, punching opening current transformer next door connects a special-purpose lightning arrester.
Implement this method and require each road earth current to gather earth connection, each grounding transformer neutral point, the high-pressure side neutral ground line of voltage transformer all must be connected in the 10KV of transformer station, the 35KV switch gear room on the main ground network reliably.
For realizing the inventive method; Specialized designs a kind of protective device; Protective device is made up of cable line one-phase ground protection unit, overhead transmission line one-phase ground protection unit, ground protection current interlock unit, ground protection voltage blocking unit, digital to analog converter and display, and each cellular construction is following:
1, cable line one-phase ground protection unit pack contains current relay LJ; Earth current display element A; Series connection inserts in its protection major loop has current interlock contact LJZ and voltage blocking contact YJ; The circuit part that parallel connection inserts in its protection major loop is: instantaneous operation time control element SJ with move in signal circuit section after signal controlling element XJ connects, deferred action time control element SJ1 with move in the trip circuit part after switch trip control element TQ connects.
2, the structure of overhead transmission line one-phase ground protection unit is identical with cable line one-phase ground protection unit; Ground protection current interlock unit shows that by total earth current transmitter LJZ and earth current data A two parts constitute; Ground protection voltage blocking unit shows that by voltage transmitter YJ, 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 LJ of cable line one-phase ground protection unit is from the punching opening current transformer of cable line; The input signal of the current transducer LJ of overhead transmission line one-phase ground protection unit is from the punching opening current transformer of overhead transmission line; The input signal of total earth current transmitter LJZ of ground protection current interlock unit is from the opening current transformer of system transformer, and the input signal of ground protection voltage blocking unit is from bus-bar potential transformer secondary insulating monitoring open delta coil; The output signal of cable line one-phase ground protection unit, overhead transmission line one-phase ground protection unit, ground protection current interlock unit and ground protection voltage blocking unit is delivered to display behind digital to analog converter.
New method of measurement and protective device are owing to adopted special fault-signal measurement point; Compare with device with the existing technology that extensively adopts; Improved the discrimination of fault, made protective device can select faulty line reliably and move in tripping operation and send fault-signal.
Description of drawings:
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, cable line 2, bus-bar potential transformer 3, system earth transformer 4, system earth transformer neutral point are gathered earth current instrument transformer 5, cable line is gathered ground network 7 in earth current instrument transformer 6, the switch gear room, the special-purpose earth fault current lead-in wire of lightning arrester 8, cable outlet 9, user's ground network 10, the open delta voltage transmitter 11 of bus-bar potential transformer, overhead transmission line collection overhead transmission line earth current instrument transformer 12, lightning arrester 13, anticorrosion earth connection 14, grounding electrode 15, overhead transmission line 16.
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 practical implementation method and apparatus of the present invention is done further detailed explanation.
Fig. 1 has provided isolated neutral system earth fault signal measurement method and protective device key wiring diagram, and to cable outlet and every overhead transmission line outlet of transformer station, the method for measuring fault-signal that adopts is respectively:
1, to the cable line outlet of transformer station; Fault-signal measures the bonding thread end that a little is selected in the house cable head; Lay a special-purpose earth fault current lead-in wire (9) in the end; Go up an installation punching opening current transformer (6) in (9), invade, connect a special-purpose lightning arrester (8) on punching opening current transformer (6) next door in order to prevent lightning surge.
2, to the overhead transmission line outlet of transformer station; It is underground that fault-signal measures the path of No. 0 bar to 6 bar that a little is selected in outlet; Select a solution space; And, lay an earth current collection line (14) that links to each other with earth electrode (15) along going out thread path, at the current acquisition line at the underground grounding electrode (15) of burying underground
A punching opening current transformer (12) is installed on the proper site (14), and is connect a special-purpose lightning arrester (13) on (12) next door, grounding electrode and earth connection need pass through preservative treatment.
3, punching opening current transformer (6) and (12) last secondary singal of gathering are delivered to checkout gear, as the signal source of fault distinguishing.
4, a punching opening current transformer (5) is installed on the neutral ground line of the neutral point (or arc suppression coil) (4) of substation grounding transformer; As the reliable signal source of judging line-to-ground, punching opening current transformer (5) next door connects a special-purpose lightning arrester (8).
This method requires each road earth current to gather earth connection, each grounding transformer neutral point, and the high-pressure side neutral ground line of voltage transformer all must be connected in the 10KV of transformer station, the 35KV switch gear room on the main ground network reliably.
Fig. 2 has provided isolated neutral system earth-fault protection block diagram; This protective device is made up 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 protected location structure of device is following:
1, cable line one-phase ground protection unit (17) include current relay LJ; Earth current display element A; Series connection inserts in its protection major loop has current interlock contact LJZ and voltage blocking contact YJ; The circuit part that parallel connection inserts in its protection major loop is: instantaneous operation time control element SJ with move in signal circuit section after signal controlling element XJ connects, deferred action time control element SJ1 with move in the trip circuit part after switch trip control element TQ connects.
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) shows that by total earth current transmitter LJZ and earth current data A two parts constitute; Ground protection voltage blocking unit (20) shows that by voltage transmitter YJ, 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 LJ of cable line one-phase ground protection unit (17) is from punching opening current transformer (6); The input signal of the current transducer LJ of overhead transmission line one-phase ground protection unit (18) is from punching opening current transformer (12); The input signal of total earth current transmitter LJZ of ground protection current interlock unit (19) is from opening current transformer (5), and the input signal of ground protection voltage blocking unit (20) is from bus-bar potential transformer secondary insulating monitoring 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) behind digital to analog converter (21).
The protective device action specification is following:
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) through cable screening wire.Current transducer on the cable shield earth connection (6) 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, the line-to-ground electric current is gathered the neutral point that line (14) is back to grounding transformer (4) along underground earth electrode of burying underground of overhead transmission line (15) and earth current.Line-to-ground current transducer (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 current transducer (5) that the grounding transformer neutral point is installed starts LJ Z junction closure simultaneously.The open delta voltage transmitter voltage of bus-bar potential transformer raises, and starting YJ contact is through time component SJ1 timing closing, and the ground fault circuit interrupteur work of cutting off is accomplished in trigger circuit ground protection unit (17) (18).
4, circuit generation transient earthing fault; Line-to-ground current transducer (6), (12), the current transducer (5) that the grounding transformer neutral point is installed, insulating monitoring open delta voltage YJ contact; Time SJ contact is closed simultaneously, sends concrete certain circuit transient earthing signal.
5, circuit transient earthing YJ voltage blocking contact and time SJ 1 contact are not closed, and the protection trip(ping) circuit is failure to actuate.
6, circuit generation permanent earth fault, LJ, LJZ, voltage blocking contact YJ and time SJ-1 contact are closed simultaneously, and the disengagement failure line work is accomplished in the start protection trip(ping) circuit.
7, normal operating leakage current of cable line and overhead transmission line and capacitance current show on screen through the current transducer analog-to-digital conversion.
The concrete wiring of this protective device is carried out according to the wiring requirement and the rules of relaying protection; Elements such as electric, the electronics of being selected for use in the device, electrical equipment; All select electrician's components and parts general in the international standard for use, the concrete wiring of each element is carried out by the element requirement, does not elaborate at this.
Claims (4)
1. isolated neutral system earth fault signal measurement method and protective device is characterized in that said method of measurement may further comprise the steps:
(1) to the cable line outlet of transformer station; Fault-signal measures the bonding thread end that a little is selected in cable end; Lay a special-purpose earth fault current lead-in wire (9) in the end; Go up an installation punching opening current transformer (6) at current feed (9), punching opening current transformer (6) next door connects a special-purpose lightning arrester (8);
(2) to the overhead transmission line outlet of transformer station; It is underground that fault-signal measures the path of No. 0 bar to 6 bar that a little is selected in outlet; At the underground grounding electrode (15) of burying underground, lay an earth current collection line (14) that links to each other with earth electrode (15) along going out thread path, current acquisition line (14) is gone up a punching opening current transformer (12) is installed; Punching opening current transformer (12) next door connects a special-purpose lightning arrester (13), and grounding electrode and earth connection need pass through preservative treatment;
(3) punching opening current transformer (6) and (12) last secondary singal of gathering are delivered to checkout gear, as the signal source of fault distinguishing;
(4) a punching opening current transformer (5) is installed on the earth connection of the neutral point (or arc suppression coil) (4) of substation grounding transformer, punching opening current transformer (5) next door connects a special-purpose lightning arrester (8).
2. isolated neutral system earth fault signal measurement method according to claim 1 and protective device; It is characterized in that: each road earth current is gathered earth connection, each grounding transformer neutral point; The high-pressure side neutral ground line of voltage transformer all must be connected in the 10KV of transformer station, the 35KV switch gear room on the main ground network reliably.
3. isolated neutral system earth-fault protection according to claim 1; It is characterized in that: protective device is made up 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 protected location structure is following:
(1) cable line one-phase ground protection unit (17) include current relay LJ; Earth current display element A; Series connection inserts in its protection major loop has current interlock contact LJZ and voltage blocking contact YJ; The circuit part that parallel connection inserts in its protection major loop is: instantaneous operation time control element SJ with move in signal circuit section after signal controlling element XJ connects, deferred action time control element SJ1 with move in the trip circuit part after switch trip control element TQ connects;
(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) shows that by total earth current transmitter LJZ and earth current data A two parts constitute; Ground protection voltage blocking unit (20) shows that by voltage transmitter YJ, insulation voltage data element V two parts constitute.
4. isolated neutral system earth-fault protection according to claim 3; It is characterized in that: the input signal of the current relay LJ of cable line one-phase ground protection unit (17) is from punching opening current transformer (6); The input signal of the current transducer LJ of overhead transmission line one-phase ground protection unit (18) is from punching opening current transformer (12); The input signal of total earth current transmitter LJZ of ground protection current interlock unit (19) is from opening current transformer (5), and the input signal of ground protection voltage blocking unit (20) is from bus-bar potential transformer secondary insulating monitoring 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) behind digital to analog converter (21).
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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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| 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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| CN102332707A true CN102332707A (en) | 2012-01-25 |
| CN102332707B CN102332707B (en) | 2014-04-16 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106329509A (en) * | 2015-06-18 | 2017-01-11 | 上海金艺检测技术有限公司 | Small current fault line selection protection system of power grid isolated neutral system |
| CN106896298A (en) * | 2015-12-17 | 2017-06-27 | 本德尔有限两合公司 | Method and apparatus for the insulation fault location in ungrounded electric power system, for electric power system condition monitoring method |
| 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 |
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| US20050073780A1 (en) * | 2003-10-07 | 2005-04-07 | Elms Robert T. | Fault detector for two line power distribution system and protection apparatus incorporating the same |
| 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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Patent Citations (4)
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| 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 |
| US20050073780A1 (en) * | 2003-10-07 | 2005-04-07 | Elms Robert T. | Fault detector for two line power distribution system and protection apparatus incorporating the same |
| 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 |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106329509A (en) * | 2015-06-18 | 2017-01-11 | 上海金艺检测技术有限公司 | Small current fault line selection protection system of power grid isolated neutral system |
| 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 |
| CN106896298A (en) * | 2015-12-17 | 2017-06-27 | 本德尔有限两合公司 | Method and apparatus for the insulation fault location in ungrounded electric power system, for electric power system condition monitoring method |
| CN106896298B (en) * | 2015-12-17 | 2021-11-23 | 本德尔有限两合公司 | Method and device for insulation fault localization in an ungrounded power supply system, method for condition monitoring of a power supply 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 |
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