CN102867119A - Method and device for estimating state of oil-immersed transformer - Google Patents

Abstract

The present invention relates to a state evaluation method for an oil-immersed transformer, which uses the theoretical health index HI ₁ of the transformer and the experimental health index HI ₂ to obtain a state evaluation index HI, which is used to evaluate the health state of the transformer, where 0< <1, Indicates the proportional coefficient of the theoretical health index HI ₁ , and satisfies: ; On this basis, call the maintenance strategy of the transformer based on the obtained HI. Through the theoretical health index and the experimental health index, the present invention simplifies the transformer maintenance work in the prior art in a form as simple and complete as possible.

Description

A state evaluation method and device for an oil-immersed transformer

the

technical field

The invention relates to the field of electrical technology, in particular to a method for evaluating the state of an oil-immersed transformer and a device thereof.

Background technique

With the rapid development of my country's electric power industry, power transformers are developing in the direction of ultra-high voltage and large capacity, and the power grid is also being organized into a huge regional or even trans-regional power grid. A connected grid pattern is taking shape. However, with the increase in the capacity of power equipment and the expansion of the grid scale, higher requirements have been put forward for the safe operation of the power system and the reliability of power supply. alarm bell. The oil-immersed power transformer plays an important role in the power system. It is one of the most important and expensive electrical equipment in the power system. The safety and reliability of its operation are directly related to the safety and stability of the power system. Therefore, improving the reliability of power transformers, especially large-scale power transformers, is of great significance to the safe and reliable operation of the entire power grid.

In addition to improving the reliability of the transformer in the design and manufacture process, it is more important to improve the maintenance and repair level of the transformer in the operation process. For a long time, the maintenance strategy of transformers in my country's power system has adopted the regular maintenance mode. That is to say, regardless of the structure of the transformer, the technical level of the manufacturer and the quality of the product, whether there has been a short circuit at the outlet, etc., regular maintenance should be carried out in accordance with relevant standards. On the one hand, regardless of the state of the transformer, this method of repairing at the specified time often causes transformers that do not need to be repaired to be "cured for minor illnesses or even for no diseases". Carrying out outage maintenance or even replacing equipment will cause a lot of waste of manpower, material resources and financial resources. At the same time, due to the moisture and dust in the air entering the transformer during the overhaul, the insulation level of the transformer that does not need to be overhauled may be reduced after the overhaul, which increases the possibility of new hidden dangers of the transformer during the overhaul process. On the other hand, for transformers with serious defects or faults that really need to be overhauled, they are not overhauled in time because the overhaul period is not reached, so that the defects continue to develop and lead to accidents, which cannot ensure the safe operation of the power grid.

Contents of the invention

The present invention aims to solve the technical problem of state evaluation of transformers and proposes a state evaluation method for oil-immersed transformers, which is characterized in that:

Step (1): Obtain the theoretical health index HI ₁ of the transformer, the index HI ₁ is greater than 0, and the index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself;

Step (2): Obtain the test health index HI ₂ of the transformer, the index HI ₂ is greater than 0, and the index HI ₂ is determined according to the test results of the transformer, the test results include the body oil chromatography index HIF ₁ , the body Oil quality index HIF ₂ , body dielectric loss index HIF ₃ , load index HIF ₄ , historical failure index HIF ₅ , casing dielectric loss index HIF ₆ , polarization index HIF ₇ , DC resistance HIF ₈ , partial discharge index HIF ₉ , On-load tap changer oil chromatographic index HIF ₁₀ , and on-load tap changer oil quality index HIF ₁₁ , and HIF ₁ to HIF ₁₁ are all greater than 0;

<1，

表示理论健康指数HI₁的比例系数，且满足： Step (3): Obtain the status evaluation index HI, which is used to evaluate the health status of the transformer, where 0<

<1,

Indicates the proportional coefficient of the theoretical health index HI ₁ , and satisfies:

;

Step (4): Based on the obtained HI, call the maintenance strategy of the transformer.

In addition, the present invention also discloses a device for implementing the above evaluation method, wherein the device includes:

The theoretical health index acquisition unit is used to obtain the theoretical health index HI ₁ of the transformer, the index HI ₁ is greater than 0, and the index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself;

The experimental health index acquisition unit is used to obtain the experimental health index HI ₂ of the transformer, the index HI ₂ is greater than 0, and the index HI ₂ is determined according to the test results of the transformer, and the test results include the bulk oil chromatography index HIF _1. Body oil quality index HIF ₂ , body dielectric loss index HIF ₃ , load index HIF ₄ , historical failure index HIF ₅ , casing dielectric loss index HIF ₆ , polarization index HIF ₇ , DC resistance HIF ₈ , partial discharge index HIF _9. On-load tap changer oil chromatographic index HIF ₁₀ , and on-load tap changer oil quality index HIF ₁₁ , and HIF ₁ to HIF ₁₁ are all greater than 0;

表示理论健康指数HI₁的比例系数，且满足： The state evaluation index acquisition unit is used to obtain the state evaluation index HI, and the index HI is used to evaluate the health status of the transformer, where 0< <1,

Indicates the proportional coefficient of the theoretical health index HI ₁ , and satisfies:

；

;

The maintenance strategy invoking unit is used for invoking the maintenance strategy of the transformer according to the obtained HI.

Detailed ways

In order to facilitate those skilled in the art to understand the present invention, the present invention is further described.

Regarding the technical solution of the oil-immersed transformer state evaluation method disclosed in the present invention, it is characterized in that:

Step (1): Obtain the theoretical health index HI ₁ of the transformer, the index HI ₁ is greater than 0, and the index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself;

Step (2): Obtain the test health index HI ₂ of the transformer, the index HI ₂ is greater than 0, and the index HI ₂ is determined according to the test results of the transformer, the test results include the body oil chromatography index HIF ₁ , the body Oil quality index HIF ₂ , body dielectric loss index HIF ₃ , load index HIF ₄ , historical failure index HIF ₅ , casing dielectric loss index HIF ₆ , polarization index HIF ₇ , DC resistance HIF ₈ , partial discharge index HIF ₉ , On-load tap changer oil chromatographic index HIF ₁₀ , and on-load tap changer oil quality index HIF ₁₁ , and HIF ₁ to HIF ₁₁ are all greater than 0;

<1，表示理论健康指数HI₁的比例系数，且满足： Step (3): Obtain the status evaluation index HI, which is used to evaluate the health status of the transformer, where 0<

<1, Indicates the proportional coefficient of the theoretical health index HI ₁ , and satisfies:

;

Step (4): Based on the obtained HI, call the maintenance strategy of the transformer.

As far as step (1) of the above technical solution is concerned, the theoretical health index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself. For those skilled in the art, transformers usually adopt an oil-paper insulation structure. During the long operation process, due to electrical, thermal and other stresses, especially under the action of thermal stress, the oil-paper insulation will gradually age, and the aging process is also the gradual aging of the equipment. process of deterioration. It is from this point that the theoretical health index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself.

As far as step (2) of the above technical solution is concerned, in theory, in the calculation of HI ₂ , in fact, all tests for transformers can be included. In practice, considering that there are many parameters of the transformer itself, the present invention adopts The 11 parameters mentioned in step (2).

，更优选的，＝0.4。当然，不同地区使用的、不同品牌、型号的变压器，由于工作环境的差异，

可能有其他更好的取值范围。 As far as step (3) of the above technical solution is concerned, those skilled in the art can understand the core idea of the present invention accordingly. The state evaluation index HI in the present invention is obviously obtained based on the aging law of the transformer and the above-mentioned test results A value representing the current health of the transformer. In practice, the applicant found that both the theoretical health index and the experimental health index will have an impact on the health state of the transformer. It is precisely from this idea that the technical solution of the present invention comes into being. For HI, HI ₁ , and HI ₂ in this embodiment, since the health of the transformer starts to deteriorate once it is in operation, its values are obviously greater than 0 from its physical meaning. Generally speaking, for the convenience of discussion, the maximum value of HI ₁ and HI ₂ can be artificially specified. For example, if the maximum value is 10, then according to the above scheme, it is obvious that the maximum value of HI is also 10. When 10 is taken, it means that the index The health status reflected is very bad, and correspondingly, the closer its value is to 0, the better the device status is. preferred,

, and more preferably, = 0.4. Of course, transformers of different brands and models used in different regions, due to differences in working environments,

There may be other better value ranges.

Although the theoretical health index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself, there is currently no unified formula to characterize the aging law because the operating state of the transformer involves various parameters. In practice, more It is various empirical formulas or algorithms adopted by various regions or companies. More well-known is a health index aging model formula of British EA Company, which is an empirical formula based on the principle of equipment aging and reflects the change process of equipment health level index over time. It is currently widely used in the health of power equipment in the UK and North America. State evaluation, the formula is of the form:

,

In the formula: HI ₀ represents the initial health index of the transformer, which is generally 0.5; B represents the aging coefficient, which is related to the expected life of the transformer; T ₁ represents the initial aging time, which is generally the year when the transformer is put into operation; T ₂ represents the corresponding years.

Similarly, in another embodiment, the calculation of HI ₂ also adopts various empirical formulas, taking the following calculation formula as an example:

 ，

,

表示HIF₁至HIF₉关于HI₂的比例系数，0<

<1。就该公式而言，其能够使得试验结果涵盖本发明所考察的11种因素，从这一点上讲，本发明的评估方法也是较完备的。类似的，HI₁，HI₂，HIF₁至HIF₁₁最大值均可以取10。优选的，,

＝0.6，更优选的，

＝0.4，

＝0.6。当然，不同地区使用的、不同品牌、型号的变压器，由于工作环境的差异，

、

可能有其他更好的取值范围。 In the formula: K _i represents the weight coefficient of HIF _i ,

Indicates the scale factor of HIF ₁ to HIF ₉ with respect to HI ₂ , 0<

<1. As far as the formula is concerned, it can make the test results cover the 11 factors investigated in the present invention. From this point of view, the evaluation method of the present invention is relatively complete. Similarly, the maximum value of HI ₁ , HI ₂ , HIF ₁ to HIF ₁₁ can all be 10. preferred, ,

=0.6, more preferably,

=0.4,

= 0.6. Of course, transformers of different brands and models used in different regions, due to differences in working environments,

,

There may be other better value ranges.

Preferably, in another embodiment, if the maximum value of HI ₁ is set to 10, and HI ₀ is set to 0.5, then:

。

.

In particular, the present invention also discloses a device for implementing the above assessment method, characterized in that the device includes:

The theoretical health index acquisition unit is used to obtain the theoretical health index HI ₁ of the transformer, the index HI ₁ is greater than 0, and the index HI ₁ is a theoretical value calculated according to the insulation aging law of the transformer oil paper itself;

The experimental health index acquisition unit is used to obtain the experimental health index HI ₂ of the transformer, the index HI ₂ is greater than 0, and the index HI ₂ is determined according to the test results of the transformer, and the test results include the bulk oil chromatography index HIF _1. Body oil quality index HIF ₂ , body dielectric loss index HIF ₃ , load index HIF ₄ , historical failure index HIF ₅ , casing dielectric loss index HIF ₆ , polarization index HIF ₇ , DC resistance HIF ₈ , partial discharge index HIF _9. On-load tap changer oil chromatographic index HIF ₁₀ , and on-load tap changer oil quality index HIF ₁₁ , and HIF ₁ to HIF ₁₁ are all greater than 0;

<1，

表示理论健康指数HI₁的比例系数，且满足： The state evaluation index acquisition unit is used to obtain the state evaluation index HI, and the index HI is used to evaluate the health status of the transformer, where 0<

<1,

Indicates the proportional coefficient of the theoretical health index HI ₁ , and satisfies:

;

The maintenance strategy invoking unit is used for invoking the maintenance strategy of the transformer according to the obtained HI.

In summary, the present invention solves the problem that the state of the transformer is difficult to evaluate, and provides a corresponding evaluation method and device. Through the theoretical health index and the experimental health index, the transformer in the prior art is simplified in a form as simple and complete as possible. maintenance work.

The above examples have described the present invention in detail. Those skilled in the art can make various changes to the present invention according to the above description.

Claims (8)

1. oil-filled transformer state evaluating method is characterized in that:

Step (1): the theoretical health index HI that obtains transformer ₁, described index HI ₁Greater than 0, and described index HI ₁It is the theoretical value that the insulation ag(e)ing rule according to transformer oilpaper self calculates;

Step (2): the test health index HI that obtains transformer ₂, described index HI ₂Greater than 0, and described index HI ₂Be to determine according to the test findings to transformer, described test findings comprises body oil chromatography index HIF ₁, body oil index HIF ₂, body dielectric loss index HIF ₃, load factor HIF ₄, historical failure index HIF ₅, sleeve pipe dielectric loss index HIF ₆, polarization index HIF ₇, direct current resistance HIF ₈, shelf depreciation index HIF ₉, on-load voltage regulating switch oil chromatography index HIF ₁₀, and on-load voltage regulating switch oil index HIF ₁₁, and HIF ₁To HIF ₁₁All greater than 0;

Step (3): obtain state estimation index HI, described index HI is for assessment of the health status of transformer, wherein 0＜ ＜1, representation theory health index HI ₁Scale-up factor, and satisfy:

；

Step (4): take gained HI as foundation, call the maintenance strategy of transformer.

2. state evaluating method as claimed in claim 1 is characterized in that:

?，

In the formula: HI ₀The initial health index of indication transformer is generally 0.5; B represents aging coefficient, and is relevant with the expected life of transformer; T ₁The aging initial time of expression is generally transformer and puts into operation the time; T ₂The time of the correspondence that expression will be calculated.

3. state evaluating method as claimed in claim 1 is characterized in that:

，

In the formula: K _iExpression HIF _iWeight coefficient,

Expression HIF ₁To HIF ₉About HI ₂Scale-up factor, 0＜

＜1.

4. state evaluating method as claimed in claim 2 is characterized in that: establish HI ₁Maximal value be 10, HI ₀Be 0.5, then have:

。

5. such as the arbitrary described state evaluating method of claim 2-4, it is characterized in that: establish HI ₁, HI ₂, HIF ₁To HIF ₁₁Maximal value is 10.

6. such as the arbitrary described state evaluating method of claim 2-5, it is characterized in that:

，

＝0.6。

7. such as the arbitrary described state evaluating method of claim 2-5, it is characterized in that:

＝0.4，

＝0.6。

8. be used for implementing the device of claim 1-7 either method, it is characterized in that, described device comprises:

Theoretical health index acquiring unit is in order to obtain the theoretical health index HI of transformer ₁, described index HI ₁Greater than 0, and described index HI ₁It is the theoretical value that the insulation ag(e)ing rule according to transformer oilpaper self calculates;

Test health index acquiring unit is in order to obtain the test health index HI of transformer ₂, described index HI ₂Greater than 0, and described index HI ₂Be to determine according to the test findings to transformer, described test findings comprises body oil chromatography index HIF ₁, body oil index HIF ₂, body dielectric loss index HIF ₃, load factor HIF ₄, historical failure index HIF ₅, sleeve pipe dielectric loss index HIF ₆, polarization index HIF ₇, direct current resistance HIF ₈, shelf depreciation index HIF ₉, on-load voltage regulating switch oil chromatography index HIF ₁₀, and on-load voltage regulating switch oil index HIF ₁₁, and HIF ₁To HIF ₁₁All greater than 0;

State estimation index acquiring unit, in order to obtaining state estimation index HI, described index HI is for assessment of the health status of transformer, wherein 0＜ ＜1, representation theory health index HI ₁Scale-up factor, and satisfy:

；

The maintenance strategy call unit in order to foundation gained HI, calls the maintenance strategy of transformer.