CN106443302B - A kind of safe lookup method of large-sized water turbine generator Stator ground fault - Google Patents
A kind of safe lookup method of large-sized water turbine generator Stator ground fault Download PDFInfo
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- CN106443302B CN106443302B CN201610940461.6A CN201610940461A CN106443302B CN 106443302 B CN106443302 B CN 106443302B CN 201610940461 A CN201610940461 A CN 201610940461A CN 106443302 B CN106443302 B CN 106443302B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/346—Testing of armature or field windings
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- General Physics & Mathematics (AREA)
- Protection Of Generators And Motors (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
The invention discloses a kind of safe lookup methods of large-sized water turbine generator Stator ground fault, including connection DC power supply circuit, correction open C T to connect direction with ammeter, ground fault phase is determined according to insulation resistance, ground fault branch is successively determined according to current direction, determines earth fault.The present invention is simple and practical, can safely, accurately and fast find generator stator ground fault point by the safe current less than 1A；It is entirely searching in failure process, is not needing sawed-off each branch's bar tail end, reducing sawed-off, welding heavy workload, also can avoid welding fever bring risk.
Description
Technical field
The present invention relates to a kind of safe lookup methods of large-sized water turbine generator Stator ground fault.
Background technique
In electric power enterprise production, generator stator ground is a typical fault of generator.
The big wiring of large-sized water turbine generator stator volume it is complicated (such as certain 700MW generator machine stator diameter 16m, high 3.3m,
Bar 1248,8 branch of every phase), grain of rice size grounding point is accurately found, conventional method is the ground connection electricity for being applied more than 5A
Stream, allows grounding point to generate big smog to find grounding point.
Data such as " generator transformer relay protection applications " show that 1A electric current is the safety of Generator Stator ground connection
Electric current, stator grounding electric current are more than the safety that generator iron-core may be threatened after 1A.
Conventional electric generators stator grounding searches method 5A electric current, it is possible to scaling loss stator core.The country connects due to searching stator
Earth fault and scaling loss stator core event occasionally has generation, cause bigger loss.Especially large-sized water turbine generator repairs iron
The direct and consequential damage of core and electric quantity loss can exceed that hundred million yuan.Therefore the lookup of large-sized water turbine generator Stator ground fault must
Palpus is perfectly safe, is perfectly safe.
In addition, the lookup method having at present needs sawed-off each branch's tail end to reduce fault coverage, large-scale generator is generally every
8 branches of phase or so, welding workload is big, time-consuming more again after branch's tail end is sawed-off, while there are also the violent hairs welded when restoring
Heat may destroy the risk of bar insulation.
Summary of the invention
It is an object of the invention to defect, provide a kind of simple and practical, logical aiming at the problems existing in the prior art
The large-sized water turbine hair of generator stator ground fault point can safely, accurately and fast be found by crossing the safe current less than 1A
The safe lookup method of motor stator ground fault.
To achieve the goals above, the invention adopts the following technical scheme:
A kind of safe lookup method of large-sized water turbine generator Stator ground fault sets large-sized water turbine generator every phase 3
Branch, 10 bars of each branch, and number consecutively 1,2 ..., 9, general 8 of the every phase branch of 10(large-sized water turbine generator
Left and right, about 52 bars of every branch's bar, it is assumed herein that being not do protection scope for clear narration technical solution of the present invention
It limits, in the actual implementation process, can be numbered according to the actual situation)；The following steps are included:
(1) prepare a 50V DC power supply, a 200 Ω current-limiting resistances, three 0.25A ammeters, a switch and two
A open C T(current transformer to match with generator bar size)；The open C T is equipped with 25 layers of iron core, secondary side
15 circle of coiling；
(2) generator outlet A, B, C three-phase head end is unlocked to be flexible coupling, pull open neutral point isolating switch, unlock generator A, B, C tri-
Phase tail end is flexible coupling；Each phase insulation resistance of generator is measured using 2500V megameter, determines ground fault phase；
(3) DC power supply circuit is connected in the head end of ground fault phase, specifically: the positive terminal of 50V DC power supply is connected
Connect the head end of ground fault phase, the negative pole end of 50V DC power supply, switch, current-limiting resistance, 0.25A ammeter negative terminal according to
Secondary series connection；The positive ending grounding of 0.25A ammeter (ground connection can be treated as being connected at fault ground herein)；
(4) the secondary side line of two open C T is connected with other two 0.25A ammeter respectively, then by the two
Open C T is placed into the upper end of branch's Line 1 stick of ground fault phase, is closed the switch of DC power supply circuit, observe this two
The pointer of a 0.25A ammeter be biased to it is whether consistent, if inconsistent, by the secondary side line of one of open C T with
The wiring of 0.25A ammeter is exchanged, and is biased to the pointer of the two 0.25A ammeters consistent, then the two open Cs T's
Paste red-label in top；
(5) the open C T adjusted using step (4) mutually carries out ground fault at detection lookup ground fault, specifically
Are as follows:
Firstly, the two open Cs T is individually positioned at the Line 1 stick and No. 10 line stick of one of branch, observation with
The pointer of the 0.25A ammeter of open C T-phase connection is biased to, and determines ground fault branch；
Current direction is consistent between the odd number bar of the non-faulting branch in ground fault phase, current direction between even number bar
Unanimously, between odevity bar thus current direction is on the contrary, can determine, when the current direction of Line 1 stick and No. 10 line stick is opposite,
This branches into ungrounded fault branch, conversely, this branches into ground fault branch；
Then, it is determined that one of open C T is placed into other bars after ground fault branch, observation and open C T
The pointer for the 0.25A ammeter being connected is biased to, and determines grounding point according to following logic:
1. in ground fault branch, odd number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point
Before this bar；Odd number bar in the branch identical person with Line 1 stick current direction, then grounding point is in this bar
Below；
2. in ground fault branch, even number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point
Behind this bar；Even number bar in the branch identical person with Line 1 stick current direction, then grounding point is in this bar
Front；
3. some bar upper end and lower end current direction are on the contrary, then the bar is grounded in ground fault branch；
4. certain 2 adjacent bar upper and lower end parts electric currents are downward simultaneously, then their lower end connects in ground fault branch
Ground；
5. certain 2 adjacent bar upper and lower end parts electric currents are upward simultaneously, then their upper end connects in ground fault branch
Ground.
Advantages of the present invention:
1. using 50V DC power supply provides detection electric current, the electric current for flowing through stator bar is less than 1A, so that it may pacify
Entirely, generator stator ground fault point is accurately and fast found.
2. not needing sawed-off each branch's bar tail end entirely searching in failure process, sawed-off, welding extensive work is reduced
Amount also can avoid welding fever bring risk.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of one embodiment of the invention split shed CT.
Fig. 2 is the circuit diagram being grounded in the middle part of bar in one embodiment of the invention.
Fig. 3 is the circuit diagram that bar lower end is grounded in one embodiment of the invention.
Fig. 4 is the circuit diagram that bar upper end is grounded in one embodiment of the invention.
Arrow is current direction in figure.
Specific embodiment
Present invention will be further explained below with reference to the attached drawings and examples.
Embodiment:
A kind of safe lookup method of large-sized water turbine generator Stator ground fault, as shown, setting large-sized water turbine power generation
3 branches of the every phase of machine, 10 bars of each branch, and number consecutively 1,2 ..., 9, the every phase of 10(large-sized water turbine generator point
Branch general 8 or so, about 52 bars of every branch's bar, it is assumed herein that not done for clear narration technical solution of the present invention
The restriction of protection scope can be numbered according to the actual situation in the actual implementation process)；The following steps are included:
(1) prepare a 50V DC power supply, a 200 Ω current-limiting resistances, three 0.25A ammeters, a switch and two
A open C T(current transformer to match with generator bar size)；The open C T is equipped with 25 layers of iron core, secondary side
15 circle of coiling；
(2) generator outlet A, B, C three-phase head end is unlocked to be flexible coupling, pull open neutral point isolating switch, unlock generator A, B, C tri-
Phase tail end is flexible coupling；Each phase insulation resistance of generator is measured using 2500V megameter, determines ground fault phase；
(3) DC power supply circuit is connected in the head end of ground fault phase, specially (as shown in Figure 2, Figure 3, Figure 4): by 50V
The head end of the positive terminal connection ground fault phase of DC power supply, negative pole end, switch, the current-limiting resistance, one of 50V DC power supply
The negative terminal of 0.25A ammeter is sequentially connected in series；(ground connection can be treated as and phase at fault ground the positive ending grounding of 0.25A ammeter herein
Connection)；
(4) the secondary side line of two open C T is connected with other two 0.25A ammeter respectively, then by the two
Open C T is placed into the upper end (in such as Fig. 2 at A) of branch's Line 1 stick of ground fault phase, is closed DC power supply circuit
Switch, whether the pointer deviation for observing the two 0.25A ammeters is consistent, if inconsistent, by one of open C T's
The wiring of secondary side line and 0.25A ammeter is exchanged, and is biased to the pointer of the two 0.25A ammeters consistent, then this two
Paste red-label in the top of a open C T；
(5) the open C T adjusted using step (4) mutually carries out ground fault at detection lookup ground fault, specifically
Are as follows:
Firstly, the two open Cs T is individually positioned at the Line 1 stick and No. 10 line stick of one of branch, observation with
The pointer of the 0.25A ammeter of open C T-phase connection is biased to, and determines ground fault branch；
Current direction is consistent between the odd number bar of the non-faulting branch in ground fault phase, current direction between even number bar
Unanimously, between odevity bar thus current direction is on the contrary, can determine, when the current direction of Line 1 stick and No. 10 line stick is opposite,
This branches into ungrounded fault branch, conversely, this branches into ground fault branch；
Then, it is determined that one of open C T is placed into other bars after ground fault branch, observation and open C T
The pointer for the 0.25A ammeter being connected is biased to, and determines grounding point according to following logic:
1. in ground fault branch, odd number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point
Before this bar；Odd number bar in the branch identical person with Line 1 stick current direction, then grounding point is in this bar
Below；
2. in ground fault branch, even number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point
Behind this bar；Even number bar in the branch identical person with Line 1 stick current direction, then grounding point is in this bar
Front；
3. some bar upper end and lower end current direction are on the contrary, then the bar is grounded, such as in ground fault branch
Shown in Fig. 2；
4. certain 2 adjacent bar upper and lower end parts electric currents are downward simultaneously, then their lower end connects in ground fault branch
Ground, as shown in Figure 3；
5. certain 2 adjacent bar upper and lower end parts electric currents are upward simultaneously, then their upper end connects in ground fault branch
Ground, as shown in Figure 4.
Claims (1)
1. a kind of safe lookup method of large-sized water turbine generator Stator ground fault sets every 3 points of phase of large-sized water turbine generator
Branch, 10 bars of each branch, and number consecutively 1,2 ..., 9,10；Characterized by comprising the following steps:
(1) prepare a 50V DC power supply, a 200 Ω current-limiting resistances, three 0.25A ammeters, one switch and two with
The open C T that generator bar size matches；The open C T is equipped with 25 layers of iron core, 15 circle of secondary side coiling；
(2) generator outlet A, B, C three-phase head end is unlocked to be flexible coupling, pull open neutral point isolating switch, unlock generator A, B, C three-phase tail
End is flexible coupling；Each phase insulation resistance of generator is measured using 2500V megameter, determines ground fault phase；
(3) DC power supply circuit is connected in the head end of ground fault phase, specifically: the positive terminal of 50V DC power supply is connect
The head end of earth fault phase, the negative pole end of 50V DC power supply, switch, current-limiting resistance, a 0.25A ammeter negative terminal successively go here and there
Connection；The positive ending grounding of 0.25A ammeter；
(4) the secondary side line of two open C T is connected with other two 0.25A ammeter respectively, then the two is open
CT is placed into the upper end of branch's Line 1 stick of ground fault phase, is closed the switch of DC power supply circuit, observes the two
Whether the pointer deviation of 0.25A ammeter is consistent, if inconsistent, by the secondary side line and 0.25A of one of open C T
The wiring of ammeter is exchanged, and is biased to the pointer of the two 0.25A ammeters consistent, then viscous on the top of the two open Cs T
Paste red-label；
(5) the open C T adjusted using step (4) mutually carries out ground fault at detection lookup ground fault, specifically:
Firstly, the two open Cs T is individually positioned at the Line 1 stick and No. 10 line stick of one of branch, observation and opening
The pointer for the 0.25A ammeter that CT is connected is biased to, and determines ground fault branch；
Current direction is consistent between the odd number bar of the non-faulting branch in ground fault phase, current direction one between even number bar
It causes, current direction between odevity bar, should when the current direction of Line 1 stick and No. 10 line stick is opposite on the contrary, thus can determine
Ungrounded fault branch is branched into, conversely, this branches into ground fault branch；
Then, it is determined that one of open C T is placed into other bars after ground fault branch, observation connects with open C T-phase
The pointer of the 0.25A ammeter connect is biased to, and determines grounding point according to following logic:
1. odd number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point is at this in ground fault branch
Before a bar；Odd number bar in the branch identical person with Line 1 stick current direction, then grounding point is after this bar
Face；
2. even number bar and the inconsistent person of Line 1 stick current direction in branch, then grounding point is at this in ground fault branch
Behind a bar；Even number bar in the branch identical person with Line 1 stick current direction, then grounding point is before this bar
Face；
3. some bar upper end and lower end current direction are on the contrary, then the bar is grounded in ground fault branch；
4. certain 2 adjacent bar upper and lower end parts electric currents are downward simultaneously in ground fault branch, then their lower end ground connection；
5. certain 2 adjacent bar upper and lower end parts electric currents are upward simultaneously in ground fault branch, then their upper end ground connection.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610940461.6A CN106443302B (en) | 2016-11-02 | 2016-11-02 | A kind of safe lookup method of large-sized water turbine generator Stator ground fault |
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|---|---|---|---|
| CN201610940461.6A CN106443302B (en) | 2016-11-02 | 2016-11-02 | A kind of safe lookup method of large-sized water turbine generator Stator ground fault |
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| CN106443302B true CN106443302B (en) | 2019-09-06 |
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| CN110618343A (en) * | 2019-09-30 | 2019-12-27 | 广西桂冠电力股份有限公司 | Device and method for searching generator stator bar ground fault point |
| CN111650533B (en) * | 2020-06-15 | 2022-08-23 | 国家电网有限公司 | Searching method of rotor magnetic pole grounding point searching instrument |
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| US7253634B1 (en) * | 2006-03-31 | 2007-08-07 | General Electric Company | Generator protection methods and systems self-tuning to a plurality of characteristics of a machine |
| CN101295004B (en) * | 2007-04-24 | 2011-04-06 | 许继集团有限公司 | Method for judging single-phase grounding fault point position of generator stator winding |
| CN101719657B (en) * | 2009-12-24 | 2012-06-06 | 中国电力科学研究院 | System and method for simulating internal fault of electric generator |
| CN102508119B (en) * | 2011-12-09 | 2013-11-06 | 江苏宏安变压器有限公司 | Method for positioning earth faults of parallel loop of IT (Isolation-Terre) power system |
| CN102692583B (en) * | 2012-06-19 | 2014-06-11 | 国电大渡河检修安装有限公司 | Finding method of multi-branch-circuit power generator stator winding grounded short circuit point |
| US20140058202A1 (en) * | 2012-08-21 | 2014-02-27 | Robert Rife | Bronchoscope cleaning device and method |
| CN103529348B (en) * | 2013-10-15 | 2016-08-10 | 林生得 | A kind of high tension cable fault monitoring method |
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