CN115436714A - Transformer dielectric loss judgment method - Google Patents
Transformer dielectric loss judgment method Download PDFInfo
- Publication number
- CN115436714A CN115436714A CN202211064327.6A CN202211064327A CN115436714A CN 115436714 A CN115436714 A CN 115436714A CN 202211064327 A CN202211064327 A CN 202211064327A CN 115436714 A CN115436714 A CN 115436714A
- Authority
- CN
- China
- Prior art keywords
- transformer
- dielectric loss
- iron core
- loss data
- lapped
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2688—Measuring quality factor or dielectric loss, e.g. loss angle, or power factor
- G01R27/2694—Measuring dielectric loss, e.g. loss angle, loss factor or power factor
-
- 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
- G01R31/62—Testing of transformers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Relating To Insulation (AREA)
Abstract
The invention discloses a transformer dielectric loss judging method, wherein a copper braided wire is lapped on a metal part on a transformer core and is grounded, and a dielectric loss tester is used for measuring the dielectric loss of the transformer again; if the dielectric loss data of the transformer is reduced after the copper braided wires are lapped and the dielectric loss data of the transformer accords with a required value, judging that the transformer has the defect of poor iron core grounding; if the transformer dielectric loss data is reduced after the copper braided wires are lapped and exceeds the required value, judging that the transformer has the defects of poor iron core grounding and insulation system defects; and if the dielectric loss data of the transformer is unchanged after the copper braided wires are lapped, judging that the transformer has the defect of an insulation system. The method can quickly and accurately judge whether the problem is caused by the defect of poor grounding of the transformer core or the defect of the transformer insulation system.
Description
Technical Field
The invention belongs to the field of manufacturing of power transformers, and particularly belongs to a transformer dielectric loss judgment method.
Background
Insulation is lossy, and under the action of an alternating electric field, the current flowing through the insulation consists of two parts: one part is capacitance current, the other part is active current, and an included angle delta formed by the two parts of current is small. In the field of transformer manufacturing, dielectric loss factor (abbreviated as dielectric loss) tan δ has been widely used as one of important means for judging whether the insulation state of a product is good or not together with insulation resistance. By measuring the dielectric loss factor of the transformer insulation, a series of defects of the insulation, such as wetting, insulation oil dirt or aging depreciation, air gap discharge in the insulation and the like, can be reflected.
However, when the grounding of the transformer core is in a problem, the dielectric loss is increased, and if the grounding is not known or the direction judgment is not correct, no matter how the transformer oil and the insulation system are processed, the dielectric loss is not reduced, so that the serious waste of manpower and capital is caused, and the product cannot be delivered from a factory.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a transformer dielectric loss judgment method which can quickly and accurately judge whether the problem is caused by the defect of poor grounding of a transformer core or the defect of an insulation system of a transformer.
In order to achieve the purpose, the invention provides the following technical scheme:
a transformer dielectric loss judging method is characterized in that a copper braided wire is lapped on a metal part on a transformer iron core and is grounded, and a dielectric loss tester is used for measuring the transformer dielectric loss again;
if the transformer dielectric loss data is reduced after the copper braided wires are lapped and the transformer dielectric loss data accords with a required value, judging that the transformer has the defect of poor iron core grounding;
if the dielectric loss data of the transformer is reduced after the copper braided wires are lapped and the dielectric loss data of the transformer exceeds a required value, judging that the transformer has the defects of poor iron core grounding and insulation system defects;
and if the dielectric loss data of the transformer is unchanged after the copper braided wires are lapped, judging that the transformer has the defect of an insulation system.
Preferably, the copper braided wire is lapped on a side column of the iron core of the transformer.
Preferably, the copper braided wire is lapped on an iron yoke on an iron core of the transformer.
Preferably, the copper braided wire is lapped on a core lower yoke of the transformer.
Preferably, after the judgment is finished, a plurality of copper braided wires are lapped at the position where the iron core sheet is exposed on the metal part on the transformer iron core, and then the measurement is carried out again.
Furthermore, when the dielectric loss data of the transformer is reduced and meets the requirements, and the defect of poor grounding of the iron core is judged, the measurement is not needed to be carried out again.
Further, when the dielectric loss data of the transformer is reduced and exceeds the required value, if the dielectric loss data of the transformer is reduced and meets the requirement after re-measurement, the condition that the copper wire and the iron core are not well lapped during the initial measurement is indicated, and the defect of poor grounding of the iron core is judged after re-measurement.
Further, when the transformer dielectric loss data is unchanged, if the transformer dielectric loss data is changed into 'the transformer dielectric loss data is obviously reduced and meets the requirements' after re-measurement, it is indicated that no good lap joint exists between the copper wire and the iron core during the initial measurement, and the defect of poor grounding of the iron core is judged after re-measurement; if the transformer dielectric loss data is reduced and the transformer dielectric loss data exceeds the required value, the transformer is measured again and judged to have the defects of poor iron core grounding and insulation system defects.
Preferably, dielectric loss factors tan delta between windings and the ground of windings are required to be less than or equal to 0.5% in the dielectric loss data of the transformer; and if the dielectric loss exceeds 0.5%, the dielectric loss data of the transformer exceeds the required value.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention provides a transformer dielectric loss judgment method which can be used for quickly judging whether a problem point is caused by the defect of poor grounding of a transformer core or the defect of an insulation system of a transformer when dielectric loss factor data of the transformer exceeds a required value. Even if the dielectric loss of the transformer operated on site rises, the method can be used for judging in advance and carrying out targeted treatment. Poor dielectric loss can be generally judged as the defect of the internal insulation of the transformer, but the abnormal dielectric loss can be caused when the transformer core is in poor grounding. The core is single point grounded for actual measurement. Therefore, the invention mainly aims to completely eliminate the grounding problem of the iron core by additionally grounding the iron core through the copper wire once again.
Drawings
FIG. 1 is a schematic diagram of copper braided wire lapping on a transformer core;
in the drawings: 1 is a copper braided wire; 2 is an iron core side column; 3 is iron core upper yoke; 4 is iron core lower iron yoke; and 5, a transformer coil.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
Examples
As shown in fig. 1, the method for determining dielectric loss of a transformer of the present invention can be used to quickly determine whether a problem is caused by a defect of poor grounding of a transformer core or a defect of an insulation system of the transformer. The method comprises the following steps of lapping the copper braided wire 1 on a metal part on an iron core and grounding, and is inconvenient for transformer dielectric loss judgment operation because the transformer coil 5 is sleeved outside other metal parts of the transformer.
In the embodiment, a clean and soft copper braided wire 1 is lapped on any part of an iron core side column 2 or an iron core upper iron yoke 3 and an iron core lower iron yoke 4 of the transformer, and dielectric loss of the transformer is measured again by using a dielectric loss tester; the copper braided wire 1 is fully contacted with an iron core side column 2 of the transformer or an iron core upper iron yoke 3 and an iron core lower iron yoke 4 and is grounded. Normally, the iron core can be actually seen as a whole, and only one of the iron core is overlapped. Poor dielectric loss can be generally judged as the defect of the internal insulation of the transformer, but the abnormal dielectric loss can be caused when the transformer core is in poor grounding. The core is single point grounded for actual measurement. Therefore, the invention mainly aims to completely eliminate the grounding problem of the iron core by additionally grounding the iron core once again through the copper wire.
If the dielectric loss data of the transformer after the copper braided wire 1 is lapped obviously decreases and meets the requirements, the transformer can be judged to have the defect of poor iron core grounding, and the problem of iron core grounding can be subsequently checked; the general requirements are as follows: the dielectric loss factor tan delta between windings and the ground of the windings is less than or equal to 0.5 percent; above 0.5% this indicates dielectric loss problems.
If the dielectric loss data of the transformer after the copper braided wire 1 is lapped obviously decreases but the dielectric loss still exceeds the required value, the transformer can be judged to have the defects of poor iron core grounding and insulation system, and the problems of the transformer iron core grounding and the transformer insulation system need to be processed.
If the dielectric loss data of the transformer after the copper braided wire 1 is lapped almost has no change, the transformer can be judged to have the defect of an insulation system, and the transformer insulation system needs to be processed.
The method can be used for re-measuring after a plurality of copper braided wires 1 are lapped on the exposed iron core sheets of the transformer iron core side column 2, the iron core upper iron yoke 3, the iron core lower iron yoke 4 and the like so as to completely eliminate the influence of iron core grounding on the measurement of dielectric loss of the transformer.
When the dielectric loss data of the transformer is obviously reduced and meets the requirements, the defect of poor grounding of the iron core is determined, and the measurement is not needed again.
When the dielectric loss data of the transformer is obviously reduced but the dielectric loss still exceeds the required value, if the dielectric loss data of the transformer is obviously reduced and meets the requirements after re-measurement, the condition that the copper wire and the iron core are not well lapped during the initial measurement is shown, and the defect of poor grounding of the iron core is proved through re-measurement.
When the dielectric loss data of the transformer is almost unchanged, if the dielectric loss data of the transformer is obviously reduced and meets the requirements after re-measurement, the condition indicates that no good lap joint exists between the copper wire and the iron core during the initial measurement, and the defect of poor grounding of the iron core is proved through re-measurement; if the dielectric loss data of the transformer is obviously reduced but the dielectric loss still exceeds the required value, the transformer can be judged to have the defects of poor iron core grounding and insulation system defects.
According to the transformer dielectric loss judgment method, when the dielectric loss factor data of the transformer exceeds the required value, whether the problem point is caused by the defect of poor grounding of the transformer core or the defect of the transformer insulation system can be judged quickly. Even if the dielectric loss of the transformer operated on site rises, the method can be used for judging in advance and carrying out targeted treatment.
Claims (9)
1. A transformer dielectric loss judging method is characterized in that a copper braided wire (1) is lapped on a metal part on a transformer core and is grounded, and a dielectric loss tester is used for re-measuring the transformer dielectric loss;
if the dielectric loss data of the transformer is reduced after the copper braided wire (1) is lapped and the dielectric loss data of the transformer accords with a required value, judging that the transformer has the defect of poor iron core grounding;
if the dielectric loss data of the transformer is reduced after the copper braided wire (1) is lapped and the dielectric loss data of the transformer exceeds a required value, judging that the transformer has the defects of poor iron core grounding and insulation system defects;
and if the dielectric loss data of the transformer after the copper braided wire (1) is lapped are unchanged, judging that the transformer has the defect of an insulation system.
2. The transformer dielectric loss judgment method according to claim 1, wherein the copper braided wire (1) is lapped on a core side column (2) of the transformer.
3. The transformer dielectric loss assessment method according to claim 1, wherein the copper braided wire (1) is lapped on an iron core upper yoke (3) of the transformer.
4. The transformer dielectric loss assessment method according to claim 1, wherein the copper braided wire (1) is lapped on a lower iron core yoke (4) of the transformer.
5. The transformer dielectric loss judgment method according to claim 1, wherein after the judgment is completed, a plurality of copper braided wires (1) are lapped at the position where the iron core sheet is exposed on the metal part on the transformer core, and then the measurement is carried out again.
6. The method as claimed in claim 5, wherein when the transformer dielectric loss data is reduced and meets the requirement, and it is determined that the core grounding fault is detected, the re-measurement is not required.
7. The method as claimed in claim 5, wherein when the transformer dielectric loss data is decreased and the transformer dielectric loss data exceeds the required value, if the transformer dielectric loss data is decreased and meets the requirement after re-measurement, it indicates that no good lap joint exists between the copper wire and the iron core during the initial measurement, and the re-measurement determines that the iron core is a poor grounding defect.
8. The transformer dielectric loss judgment method according to claim 5, wherein when the transformer dielectric loss data is unchanged, if the transformer dielectric loss data is changed to be 'obviously reduced and meets the requirement' after re-measurement, it indicates that no good lap joint exists between the copper wire and the iron core during the initial measurement, and the re-measurement is judged to be an iron core grounding fault defect; if the transformer dielectric loss data is reduced and the transformer dielectric loss data exceeds the required value, the transformer is measured again and judged to have the defects of poor iron core grounding and insulation system defects.
9. The method for judging the dielectric loss of the transformer according to claim 1, wherein a dielectric loss factor tan delta between the windings and the ground of the windings in the dielectric loss data of the transformer is required to be less than or equal to 0.5 percent; and if the dielectric loss exceeds 0.5%, the dielectric loss data of the transformer exceeds the required value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211064327.6A CN115436714A (en) | 2022-08-31 | 2022-08-31 | Transformer dielectric loss judgment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211064327.6A CN115436714A (en) | 2022-08-31 | 2022-08-31 | Transformer dielectric loss judgment method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115436714A true CN115436714A (en) | 2022-12-06 |
Family
ID=84244738
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211064327.6A Pending CN115436714A (en) | 2022-08-31 | 2022-08-31 | Transformer dielectric loss judgment method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115436714A (en) |
-
2022
- 2022-08-31 CN CN202211064327.6A patent/CN115436714A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6114871A (en) | Abnormality detecting method and apparatus for electrical equipment, particularly for a rotating electric machine | |
| JP5315814B2 (en) | Insulation coated conductor inspection method and apparatus | |
| CN110672644B (en) | Cable buffer layer state evaluation method and system | |
| CN1896758A (en) | Cable monitoring system and monitoring method thereof | |
| US20110022338A1 (en) | Determining degraded insulating ability in an inductively operating element | |
| KR102148618B1 (en) | Device and system for diagnosing power cable, and method for diagnosing power calbe using the same | |
| CN104374312A (en) | Method for detecting deformation of power transformer windings | |
| CN110456299B (en) | On-line detection method for turn-to-turn short circuit fault of secondary winding of current transformer | |
| CN107957529B (en) | Method and apparatus for testing current connections of a high voltage condenser bushing assembly | |
| US6870374B2 (en) | Process for identifying abnormalities in power transformers | |
| JP6164022B2 (en) | Interlayer insulation diagnosis method for winding equipment | |
| CN115436714A (en) | Transformer dielectric loss judgment method | |
| CN103837792A (en) | Device and method for detecting short circuit ring of coils of transformers | |
| CN102540030A (en) | Method for diagnosing development speed of partial discharge defect of oil paper insulated equipment | |
| KR20040008114A (en) | Method and apparatus of nondestructive insulation test for small electric machine | |
| CN113748338A (en) | Method for evaluating resistance welding quality of battery by using eddy current signal characteristics | |
| CN116699459A (en) | Method and system for detecting grounding state of intelligent end screen grounding device of high-voltage sleeve | |
| CN100447575C (en) | Method for identifying abnormal condition in power transformer | |
| CN112698158B (en) | Partial discharge electrical positioning method and device for transformer | |
| CN113567807A (en) | Method for detecting current abnormity of power cable metal sheath layer | |
| Toudji et al. | Predictive diagnostic based on HF modeling of electrical machines windings | |
| CN115656869A (en) | Iron core grounding state judgment method | |
| CN103930775A (en) | Magnetic body evaluation device and method | |
| CN113189459B (en) | Method for detecting insulation weak point of driving motor based on three-curve method | |
| WO2023171570A1 (en) | Coil manufacturing device, coil manufacturing method, stator manufacturing method, and rotating electric machine manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |