CN113945848B - Method for determining flashover discharge path of generator stator winding - Google Patents
Method for determining flashover discharge path of generator stator winding Download PDFInfo
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- CN113945848B CN113945848B CN202111202725.5A CN202111202725A CN113945848B CN 113945848 B CN113945848 B CN 113945848B CN 202111202725 A CN202111202725 A CN 202111202725A CN 113945848 B CN113945848 B CN 113945848B
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- 238000004804 winding Methods 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 24
- 230000005684 electric field Effects 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims description 13
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000007787 solid Substances 0.000 claims description 12
- 229910052802 copper Inorganic materials 0.000 claims description 7
- 239000010949 copper Substances 0.000 claims description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- 230000007423 decrease Effects 0.000 claims description 2
- 239000012212 insulator Substances 0.000 claims description 2
- 238000004364 calculation method Methods 0.000 abstract description 10
- 238000009413 insulation Methods 0.000 abstract description 10
- 238000013461 design Methods 0.000 abstract description 7
- 238000012360 testing method Methods 0.000 abstract description 6
- 230000002427 irreversible effect Effects 0.000 abstract 1
- 238000005457 optimization Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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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
- G01R31/343—Testing dynamo-electric machines in operation
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Tests Of Circuit Breakers, Generators, And Electric Motors (AREA)
Abstract
The invention discloses a method for determining a flashover discharge path of a generator stator winding. When the generator stator is in a voltage withstand test, if the insulation structure is unreasonable in design, flashover discharge between a stator winding and surrounding objects can be caused, irreversible damage is caused to the stator insulation, and the electrical test safety of the stator winding is seriously threatened. The method is combined with the calculation result of the finite element of the electric field at the end part of the generator stator, and the dangerous position of flashover discharge is rapidly positioned, so that the flashover discharge path of the generator stator is obtained. The invention has the advantages of clear principle, convenient modeling, accurate calculation, rapidness and effectiveness, can perform the insulation structure optimization design of the stator winding of the generator, improves the flashover voltage level of the stator winding withstand voltage test, and ensures the stability of the generator test and operation.
Description
Technical Field
The invention relates to the field of generators, in particular to a method for determining a flashover discharge path of a stator winding of a generator.
Background
The flashover discharge condition of the generator stator winding is a common problem in the electrical test of the generator stator winding, and seriously threatens the safety of the generator stator winding. With the improvement of the rated voltage of the generator, the flashover discharge condition of the stator winding is more obvious, the design requirement on the insulation of the stator of the generator is higher, the position and the path of the flashover discharge of the stator winding are accurately predicted, the insulation structure is optimized, the flashover voltage of the stator winding is improved, and the method has important significance for improving the design level of the stator winding of the generator and ensuring the running stability of a unit.
The finite element electric field calculation method of the stator winding of the generator is mature, and the surface potential distribution condition of the stator bar can be obtained. However, because the flashover discharge process is complex, and involves multiple disciplines such as plasma, fluid, and electric field, the calculation method for determining the location and path of the flashover discharge is still not mature, and the calculation and analysis difficulties are great. Because the space electric field of the stator winding of the generator is complex, if the possible position of flashover discharge is not obtained by a method, the influence of an insulating structure cannot be better analyzed, and the integral structure design of the end part of the stator of the generator cannot be effectively carried out.
In view of this, there is a need to develop a method of determining a generator stator winding flashover discharge path. The flashover discharge of the generator stator winding is closely related to the space electric field distribution, and the flashover discharge path, the discharge voltage, the average electric field and the discharge length of the generator stator winding are effectively determined on the basis of the finite element electric field calculation result, so that the method has important significance for the design of the generator stator insulation structure.
Disclosure of Invention
The invention aims to provide a method for determining a flashover discharge path of a generator stator winding, which comprises the following steps:
step one: the structure of the stator winding end part of the generator comprises a stator bar and a grounding metal piece, wherein an air gap exists between the stator bar and the grounding metal piece, and the structure of the stator bar consists of a copper lead, a main insulation, a groove part low-resistance anti-corona layer and an end part high-resistance anti-corona layer from inside to outside;
step two: the stator bar copper lead is connected with high voltage, the grounded metal piece and the groove part low-resistance anti-corona layer are grounded, a finite element part electric field model of the end part of the stator winding of the generator is established, and the surface potential distribution of the stator bar is obtained through solving;
step three: the shape of the lower surface of the sub-bar is set as a solid A, the shape of the grounding metal piece is set as a solid B, and the shortest distance from any point a on the solid A to the solid B is set as L a And the vertical intersection point of the light-emitting diode and the entity B is a', and the shortest distance from any point B on the entity B to the entity A is L b And the vertical intersection point of the stator bar and the entity A is b ', and according to the surface potential distribution result of the step two, the surface potential of the point a and the point b' on the entity A on the lower surface of the stator bar is U respectively a And U b' ；
Step four: traversing all points a on the entity A according to the L corresponding to the step three a And U a Obtain |U a |/L a Maximum value E of (2) mA At this time, the point on the entity A is a 0 Pair ofThe corresponding surface potential is U a0 Traversing all points B on the entity B according to the L corresponding to the step three b And U b' Obtain |U b' |/L b Maximum value E of (2) mB At this time, the point on the entity B is B 0 ；
Step five: by straight line connection a 0 And b 0 Obtaining the length L ab Average electric field strength E mAB Is |U a0 |/L ab The maximum electric field intensity path of the end part of the stator winding of the generator changes the external high voltage when the average electric field intensity E mAB When the intensity of the electric field is equal to that of the air flashover discharge, the path is determined to be the flashover discharge path of the stator winding of the generator.
In the method for determining the flashover discharge path of the stator winding of the generator, in the fifth step, external high voltage is changed, and the second step, the third step, the fourth step and the fifth step are repeated until the average electric field strength E is obtained mAB Equal to the air discharge field strength.
In the above method for determining a flashover discharge path of a stator winding of a generator, in the fifth step, as the air gap increases, the flashover discharge electric field strength decreases accordingly.
The beneficial effects of the invention are as follows:
the method for determining the flashover discharge path of the generator stator winding provided by the invention has the following technical effects that:
1. and (5) rapidly positioning a flashover discharge path of the stator winding. And combining a finite element electric field calculation result with a flashover discharge path algorithm, rapidly positioning a flashover discharge path of the stator winding, and finding out a weak position of the stator insulation structure design of the generator.
2. Detailed information of the flashover discharge is obtained. By the method, detailed information such as a flashover discharge path, a discharge voltage, a discharge average electric field, a discharge length and the like of the generator winding can be estimated and obtained, and verification and analysis of flashover discharge results are facilitated.
3. And the stator insulation structure of the auxiliary generator is optimally designed. And according to the calculation result of the flashover discharge of the stator winding, the structure of the stator component of the generator is optimally designed, so that the flashover discharge level is further improved, and the electrical test and operation stability of the generator are improved.
Drawings
Fig. 1 is a schematic diagram of an end structure of a stator winding of a generator.
FIG. 2 is a schematic diagram of a method for determining a flashover discharge path of a stator winding of a generator
The figure indicates: 1-stator bar, 2-grounding metal piece, 3-air gap, 4-copper lead wire, 5-main insulation, 6-groove part low-resistance anti-corona layer and 7-end part high-resistance anti-corona layer
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present invention and are not intended to limit the scope of protection of the present application.
The method for determining the flashover discharge path of the stator winding of the generator comprises the following steps:
step one: as shown in fig. 1, the end part structure of the stator winding of the generator comprises a stator bar 1 and a grounding metal piece 2, an air gap 3 is formed between the stator bar 1 and the grounding metal piece 2, and the structure of the stator bar 1 is composed of a copper lead 4, a main insulator 5, a groove part low-resistance anti-corona layer 6 and an end part high-resistance anti-corona layer 7 from inside to outside;
step two: as shown in fig. 1, a copper lead 4 of a stator bar 1 is connected with high voltage, a grounded metal piece 2 and a slot part low-resistance anti-corona layer 6 are grounded, a finite element part electric field model of the end part of a stator winding of a generator is established, and the surface potential distribution of the stator bar 1 is obtained by solving; the finite element method is adopted in the step to obtain the space electric field distribution condition of the stator winding end and the surface potential of each space point.
Step three: as shown in fig. 2, the shape of the lower surface of the sub-bar 1 is a solid a, the shape of the grounding metal member 2 is a solid B, and the shortest distance from any point a on the solid a to the solid B is L a And the vertical intersection point of the light-emitting diode and the entity B is a', and the shortest distance from any point B on the entity B to the entity A is L b And the vertical intersection point with the entity A is b', and the entity A on the lower surface of the stator bar 1 is obtained according to the surface potential distribution result of the step twoThe surface potentials at points a and b' are U a And U b' The method comprises the steps of carrying out a first treatment on the surface of the The shortest distance is adopted in the step to ensure that the electric field intensity at the corresponding point is higher.
Step four: as shown in fig. 2, all points a on the entity a are traversed, according to the L corresponding to step three a And U a Obtain |U a |/L a Maximum value E of (2) mA At this time, the point on the entity A is a 0 Corresponding surface potential U a0 Traversing all points B on the entity B according to the L corresponding to the step three b And U b' Obtain |U b' |/L b Maximum value E of (2) mB At this time, the point on the entity B is B 0 The method comprises the steps of carrying out a first treatment on the surface of the The function of this step to traverse all points is to find the location of the electric field intensity extremum in the whole space.
Step five: by straight line connection a 0 And b 0 Obtaining the length L ab Average electric field strength E mAB Is |U a0 |/L ab The maximum electric field intensity path of the end part of the stator winding of the generator is changed to be externally connected with high voltage, and the second step, the third step, the fourth step and the fifth step are repeated, so that the average electric field intensity E is obtained mAB When the intensity of the electric field is equal to that of the air flashover discharge, determining the path as a flashover discharge path of the stator winding of the generator; a due to high voltage variation 0 、b 0 Position, L of ab Is changed in length, resulting in an average electric field strength E mAB The corresponding air flashover discharge electric field intensity is changed, and the calculation accuracy is ensured by adopting the cyclic calculation in the step.
The method is suitable for two-dimensional and three-dimensional space conditions and is also suitable for the conditions of flashover discharge path determination in other fields.
The present invention is merely illustrative of the present invention and not limited to the scope thereof, and those skilled in the art can make modifications thereto without departing from the spirit of the invention.
Claims (3)
1. A method for determining a flashover discharge path of a stator winding of a generator is characterized by comprising the following steps:
step one: the structure of the generator stator winding end part comprises a stator bar (1) and a grounding metal piece (2), an air gap (3) is formed between the stator bar (1) and the grounding metal piece (2), and the structure of the stator bar (1) consists of a copper lead (4), a main insulator (5), a groove part low-resistance anti-corona layer (6) and an end part high-resistance anti-corona layer (7) from inside to outside;
step two: the stator bar (1) copper lead (4) is connected with high voltage, the grounding metal piece (2) and the groove part low-resistance anti-corona layer (6) are grounded, a finite element part electric field model of the end part of a stator winding of the generator is established, and the surface potential distribution of the stator bar (1) is obtained by solving;
step three: the shape of the lower surface of the sub-bar (1) is set as a solid A, the shape of the grounding metal piece (2) is set as a solid B, and the shortest distance from any point a on the solid A to the solid B is set as L a And the vertical intersection point of the light-emitting diode and the entity B is a', and the shortest distance from any point B on the entity B to the entity A is L b And the vertical intersection point with the entity A is b ', and according to the surface potential distribution result of the step two, the surface potential of the point a and the point b' on the entity A on the lower surface of the stator bar (1) is U respectively a And U b' ；
Step four: traversing all points a on the entity A according to the L corresponding to the step three a And U a Obtain |U a |/L a Maximum value E of (2) mA At this time, the point on the entity A is a 0 Corresponding surface potential U a0 Traversing all points B on the entity B according to the L corresponding to the step three b And U b' Obtain |U b' |/L b Maximum value E of (2) mB At this time, the point on the entity B is B 0 ；
Step five: by straight line connection a 0 And b 0 Obtaining the length L ab Average electric field strength E mAB Is |U a0 |/L ab The maximum electric field intensity path of the end part of the stator winding of the generator changes the external high voltage when the average electric field intensity E mAB When the intensity of the electric field is equal to that of the air flashover discharge, the path is determined to be the flashover discharge path of the stator winding of the generator.
2. The method for determining a flashover discharge path of a stator winding of a generator according to claim 1, wherein: in the fifth step, the external high voltage is changed, and the second step, the third step, the fourth step and the fifth step are repeated until the average electric field strength E is obtained mAB Equal to the air discharge field strength.
3. The method for determining a flashover discharge path of a stator winding of a generator according to claim 1, wherein: in the fifth step, as the air gap increases, the flashover discharge electric field intensity correspondingly decreases.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111202725.5A CN113945848B (en) | 2021-10-15 | 2021-10-15 | Method for determining flashover discharge path of generator stator winding |
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| CN202111202725.5A CN113945848B (en) | 2021-10-15 | 2021-10-15 | Method for determining flashover discharge path of generator stator winding |
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| CN113945848B true CN113945848B (en) | 2023-12-22 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1418437A1 (en) * | 2002-10-02 | 2004-05-12 | ALSTOM Technology Ltd | Method and electromagnetic sensor for measuring partial discharges in windings of electrical devices |
| CN1777814A (en) * | 2003-05-09 | 2006-05-24 | 西门子公司 | Measuring device, and method for locating a partial discharge |
| CN104155567A (en) * | 2014-08-30 | 2014-11-19 | 华北电力大学（保定） | Positioning method of turn-to-turn short circuit fault of doubly-fed generator rotor |
| KR101789577B1 (en) * | 2016-08-24 | 2017-10-25 | 김용주 | On-line Patial Discharge Location Monitoring Device of Rotating high voltage three-phase stator winding |
| CN110957875A (en) * | 2019-12-03 | 2020-04-03 | 哈尔滨电机厂有限责任公司 | Process method for preventing bar from mistakenly breaking down during alternating current voltage withstanding of stator winding of large motor |
| CN112305388A (en) * | 2020-10-30 | 2021-02-02 | 华能澜沧江水电股份有限公司 | On-line monitoring and diagnosing method for partial discharge fault of generator stator winding insulation |
| CN113109680A (en) * | 2021-04-30 | 2021-07-13 | 国家能源集团科学技术研究院有限公司 | Large-scale hydraulic generator stator winding partial discharge analysis system |
-
2021
- 2021-10-15 CN CN202111202725.5A patent/CN113945848B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1418437A1 (en) * | 2002-10-02 | 2004-05-12 | ALSTOM Technology Ltd | Method and electromagnetic sensor for measuring partial discharges in windings of electrical devices |
| CN1777814A (en) * | 2003-05-09 | 2006-05-24 | 西门子公司 | Measuring device, and method for locating a partial discharge |
| CN104155567A (en) * | 2014-08-30 | 2014-11-19 | 华北电力大学（保定） | Positioning method of turn-to-turn short circuit fault of doubly-fed generator rotor |
| KR101789577B1 (en) * | 2016-08-24 | 2017-10-25 | 김용주 | On-line Patial Discharge Location Monitoring Device of Rotating high voltage three-phase stator winding |
| CN110957875A (en) * | 2019-12-03 | 2020-04-03 | 哈尔滨电机厂有限责任公司 | Process method for preventing bar from mistakenly breaking down during alternating current voltage withstanding of stator winding of large motor |
| CN112305388A (en) * | 2020-10-30 | 2021-02-02 | 华能澜沧江水电股份有限公司 | On-line monitoring and diagnosing method for partial discharge fault of generator stator winding insulation |
| CN113109680A (en) * | 2021-04-30 | 2021-07-13 | 国家能源集团科学技术研究院有限公司 | Large-scale hydraulic generator stator winding partial discharge analysis system |
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