JP6354042B1 - Transformer degradation status display device - Google Patents

Abstract

Disclosed is a transformer degradation status display device capable of continuously displaying a degradation status of a transformer. One of the gradients of the graph of the degree of deterioration of the degree of polymerization of transformer insulating paper over time is defined as a degree of polymerization reduction reference gradient Kc, and an approximate expression of the insulating oil temperature with respect to the load factor of the transformer is used to diagnose Calculate the insulation paper temperature of the diagnostic transformer in the standard use condition and actual use condition from the insulation oil temperature or installation location temperature of the unit and the operating current, and the insulation paper temperature in the reference use condition and the insulation paper temperature in the actual use condition. The polymerization degree decrease gradient correction coefficient R is calculated from the insulating paper temperature difference Tzs of R = 1 / exp (−H × Tzs), and the calculated polymerization degree correction coefficient R is multiplied by the reference gradient Kc to reduce the polymerization degree. An actual gradient K is derived, and a graph 30 displays the transition of the degree of polymerization from the past to the present and the transition of the future degree of polymerization, which decreases due to the actual gradient K. [Selection] Figure 3

Description

  The present invention relates to a technique for displaying a deterioration state of a transformer as a decrease in average polymerization degree (hereinafter abbreviated as polymerization paper) of insulating paper (hereinafter abbreviated as insulation paper) mounted between transformer windings and the like. .

  The remaining life is estimated based on the degree of polymerization degree of the insulating paper, and the transformer is renewed before the life of the transformer is reached to prevent accidents due to deterioration.

As means for investigating the state of deterioration of the insulating paper, a known method for taking out a part of the insulating paper and measuring the degree of polymerization at the time of a transformer power outage, or a method such as the following literature 1 and literature 2 for estimating the degree of polymerization in the operating state Has been taken.
Japanese Patent No. 4323396 Japanese Patent No. 5387877

  The known method of taking out a part of insulating paper and measuring the degree of polymerization can only be carried out at the time of periodic inspection, and even if there is a sudden deterioration in transformer usage conditions after restarting the transformer operation, it is confirmed until the next periodic inspection Since this is not possible, the sign of an accelerated decrease in the degree of polymerization was missed, and there was a drawback that accident prevention measures such as improvement of transformer usage conditions were delayed.

  The method of Patent Document 1 that can grasp the degree of polymerization even when the transformer is operating removes the estimated thermal history of the insulating paper temperature from the load history of the diagnostic transformer, weather information, and the insulating oil temperature measured at the time of inspection. A method is employed in which the remaining life is obtained by matching with a master curve indicating the relationship between the thermal history of the insulating paper and the degree of polymerization produced from the measured value of the degree of polymerization of the transformer insulating paper.

  The method of Patent Document 2, which is another method that can grasp the degree of polymerization even when the transformer is operating, is the deterioration of CO, CO2, furfural, etc. contained in the insulating oil collected during periodic inspection of the transformer to be diagnosed. A method is used in which the degree of polymerization is estimated based on the operating environment data such as the amount of the index component, the years of operation of the transformer to be diagnosed, and the load factor, and the remaining life is obtained.

  However, the methods of Patent Document 1 and Patent Document 2 are evaluation methods for specific transformers that obtain insulation deterioration index data from insulating paper or insulating oil, and for transformers that do not obtain insulation deterioration index data. Because it is not applicable and is an intermittent evaluation method at every inspection, it will miss the sign of an accelerated decrease in the degree of polymerization when there is a sudden deterioration in transformer usage conditions after inspection, and prevent accidents. There was a drawback that it could not be implemented in a timely manner.

  The present invention has been made in view of such circumstances, and the degree of polymerization from the start of use of the transformer to the present over all transformers including small-capacity transformers in which acquisition of an insulation deterioration index is often not made. By continuously showing the state of decline, it is possible to monitor signs of decreased polymerization due to sudden changes in transformer operating conditions, and to improve transformer operating conditions in a timely manner. To do.

In order to achieve the above object, the apparatus according to claim 1 is a transformer deterioration state display device that indicates a deterioration state of a transformer by a transition of a decrease in the degree of polymerization. Insulating paper reference temperature Tzc, the insulating paper temperature under the standard use conditions (installation location reference temperature Tac (one of 6 to 18 ° C.), reference operating load factor Uc (one of 10 to 70%)) The gradient of the degree of polymerization when it is assumed to be continuously operated under the standard use conditions is any one of 10/60 to 60 / year from the degree of polymerization (one of 800 to 1000) at the start of transformer use. In the diagnostic transformer in which the operating state changes, the gradient of the degree-of-polymerization reduction straight line that has been decreased in step S is set as the degree-of-polymerization-decreasing reference gradient Kc. The correction factor R) The gradient correction coefficient R is a difference between the insulating paper temperature Tz during operation and the insulating paper reference temperature Tzc under the reference conditions. Calculation formula for insulation paper temperature difference Tzs R = 1 / exp (−H × Tzs) (Formula 1)
(Here, H is one of 0.06-0.14 (1 / ° C))
Any one of the means for calculating by the above, the first data acquisition means for acquiring the insulating oil temperature To of the diagnostic transformer, and the second data means for acquiring the installation location temperature Ta and the operating current I of the diagnostic transformer Or both data acquisition means,
In what has the said 1st data acquisition means,
The temperature To of the insulating oil, the approximate expression ^{To ≒ Ta + Tm + U x} × insulating oil temperature To on Load factor U (A-Tm) ····· (Equation 2)
(Where Ta is the temperature of the transformer installation location, Tm is the temperature rise value of the insulating oil at no load, and A is the temperature rise value of the insulating oil at the rated operation),
1-a approximate expression Tz≈Ta + Tm + U ^y × (A + Tp−Tm) of the insulating paper temperature Tz related to the load factor U (Expression 3)
(Here, Tp is the temperature difference between insulating paper and insulating oil during rated operation)
In addition, a formula for calculating the virtual load factor Ui that leads to the insulating oil temperature To derived from (Formula 2),
Ui≈ ((To-Ta-Tm) / (A-Tm)) ^{(1 / x)} (4)
Substituting the load factor by the above, 1-a insulating paper temperature calculating means for calculating the insulating paper temperature Tz at the insulating oil temperature To ;
1-b approximate expression of insulating paper temperature Tz with respect to insulating oil temperature To
Tz≈C × To (Equation 4)
(Where C is the ratio of the insulating paper temperature Tzc according to (Equation 3) to the insulating oil temperature Toc according to (Equation 2) under the standard use conditions)
1-b insulating paper temperature calculating means for calculating the insulating paper temperature Tz at the insulating oil temperature To by:
In the second data acquisition means having the second data acquisition means, the load factor U obtained by dividing the acquired operating current by the rated current is substituted into the (Equation 3) to calculate the insulation paper temperature Tz at the load factor U. Paper temperature calculation means;
An insulating paper temperature difference Tzs is obtained as a difference between the insulating paper temperature Tz calculated by any of the first -a, 1-b, or second insulating paper temperature calculating means and the insulating paper base temperature Tzc in the standard use condition. The calculated gradient correction coefficient R is calculated by substituting the calculated insulating paper temperature difference Tzs into (Equation 1), and the calculated gradient correction coefficient R is multiplied by the reference gradient Kc to obtain the actual gradient K of the gradient decrease. Means for calculating, means for storing the degree of polymerization by time and the degree of polymerization by date of the degree of polymerization lowered by the actual gradient K, and a plurality of polymerizations used for calculating a plurality of degrees of polymerization before the current time Based on the means for calculating the future degree of polymerization decrease expected gradient after the current time as the average value of the degree decrease gradient and the trial calculation conditions (transformer trial installation location temperature and trial load ratio) input from the input unit, According to the polymerization degree decrease gradient calculation means Means for calculating a future degree of polymerization lowering gradient under trial calculation conditions, a polymerization degree transition from the start of use of the diagnostic transformer to the current time read from the degree of polymerization storage unit, and future future polymerization after the current time The expected degree of polymerization along the expected decrease in degree of polymerization and the degree of polymerization after the current time along the estimated degree of decrease in degree of polymerization are shown in the long-term degree of degree transition graph from the start of use of the diagnostic transformer to several decades. It is characterized by comprising means for displaying or means for simultaneously or alternately displaying the long-term polymerization degree transition graph and the short-term polymerization degree transition graph of several days starting from the present time.

  According to the method of the present invention, over the entire transformer used in Japan, the degree of polymerization is accelerated by sudden deterioration of the use conditions by continuously showing the degree of polymerization degree deterioration from the start of use of the transformer to the present. It is possible to constantly evaluate the degree of polymerization reduction and the quality of transformer operating conditions without overlooking the state of degradation, and improve transformer operating conditions in a timely manner to prevent accidents caused by transformer deterioration. it can.

  It is a graph which shows the reference | standard gradient of the polymerization degree fall in this invention.   It is a graph which shows the temperature of the transformer insulating oil with respect to the load factor by this invention, and insulating paper.   It is an example of the long-term short-term polymerization degree transition composite display graph of the transformer deterioration display device according to the present invention.   It is a block diagram which shows the structure of the transformer degradation display apparatus by the Example of this invention.   It is a flowchart which shows the process of the transformer degradation display apparatus by the Example of this invention.   It is a graph which shows the relationship between the operation years described in JEM1463, and an average degree of polymerization.   It is a graph which shows the relationship between the operation years and the polymerization degree which are described in transformer manufacturer technical data description.   This is a survey table of transformer load factor according to type of industry published by the Japan Electrical Manufacturers' Association.   It is an example of the temperature rise graph of insulating oil and insulating paper with respect to the load factor described in Unexamined-Japanese-Patent No. 2001-291626.

  Hereinafter, the best mode for carrying out selection of a transformer according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a polymerization degree decrease reference gradient according to the present invention, based on FIGS. 6 and 7 published in Japan as a time-dependent decrease transition graph of transformer insulation paper polymerization degree. , The straight line 1a is a straight line on the upper limit side of the degree of polymerization in FIG. 7 displaying the minimum gradient in the degree-of-polymerization transition graph (the degree of polymerization at the start of operation is 900, the decrease gradient is 12.5 / year), The straight line 1b is the straight line on the polymerization degree lower limit side in FIG. 8 displaying the maximum gradient in the degree-of-polymerization transition graph (the degree of polymerization at the start of operation is 900, the decrease gradient is 50 / year), and the minimum gradient (in operation start time of the polymerization degree is 900, the reference slope K (25 / year decrease slope)) linearly 1a and maximum slope intermediate straight 1c intermediate slope of the line 1b and then, the 1a, 1b, among 1c any one of the slope of the straight line and the degree of polymerization reduction reference slope Kc of There.

  Transformer installation reference temperature Tac is based on the annual average temperature for the past 40 years according to data published by the Japan Meteorological Agency, 8 ° C in Hokkaido, 16 ° C in Kyushu, and 12 ° C in both regions. In the case of 1a, the installation location reference temperature Tac is 8 ° C., and the reference gradient Kc is 1c in FIG. 1. When the reference temperature Tac of the transformer installation location is 12 ° C. and the reference gradient Kc is 1b in FIG. Has a reference temperature Tac of 16 ° C. at the place where the transformer is installed.

The transformer operation reference load factor Uc is an average load factor 37 when the distribution of load factors of 290 cases described as per day in the transformer load factor industry survey table shown in FIG. 8 is a normal distribution. The reference gradient Kc is defined as 1a in FIG. 1 from the minimum load factor of 19.5% and the maximum load factor of 55.2% calculated from the average value ± 2σ from the standard deviation value σ = 8.93%. When the reference load factor Uc is 19.5% and the reference gradient Kc is 1c in FIG. 1, the reference load factor Uc is the insulating oil temperature at the minimum load factor 19.5% and the maximum load factor 55.2. The virtual load factor according to (Equation 4) that brings about a temperature intermediate between the insulating oil temperatures at the time of%, and the reference load factor Uc when the reference gradient Kc is 1b in FIG. 1 is 55.2%.

The insulation paper reference temperature Tzc is the insulation paper temperature when the installation location reference temperature Tac and the reference load factor Uc are applied to (Equation 3).

FIG. 2 is an approximate characteristic diagram of the insulating oil temperature To and the insulating paper temperature Tz with respect to the load factor U according to the present invention. In (Equation 2) and (Equation 3), the installation place temperature Ta is 12 ° C., and the insulation is performed at no load. Paper temperature rise value Tm is 6 ° C, insulation oil temperature rise value A during rated operation is 30 ° C, x is squared, y is 1.8th power, and temperature difference Tp between insulating hot water and insulating paper during rated operation is 15 ℃
To≈12 + 6 + U ² × (30−6) (Expression 5)
^{Tz ≒ 12 + 6 + U 1.8} × (30 + 15- 6) ···· ( Formula 6)
Is applied to approximate the published test data (FIG. 9).

H in (Formula 1), which is a formula for calculating the gradient correction coefficient R, is based on Arrhenius's half law regarding thermal degradation of insulators, and is an 8 ° C half law that is highly compatible with Class A insulating materials. R = 1 / exp (−0.8664 × Tzs) in which H = 0.08664 is adopted in the case of (Equation 7)
Has been applied.

  The acquisition of the temperature Ta of the transformer installation location in the second data acquisition means is based on the measurement of the temperature in the vicinity of the installation location or the method of adding the difference between the temperature and the installation location temperature to the meteorological agency temperature data of the installation area.

FIG. 3 is an example of a composite display graph in which a long-term display graph 30 and a short-term display graph 31 of a transformer deterioration state according to the present invention are overlapped. The degree of polymerization Jh ₂ by hour at the current time,
Jh ₂ = Jh ₁ −Δh (Equation 8)
(However, Jh ₁ is the hourly polymerization degree one hour before the current time, and Δh is the degree of polymerization reduction from one hour before to the current time shown in (Equation 9) described later)
Δh = Kcj × R (Equation 9)
(However, Kcj is a reference gradient per hour shown in (Equation 10) described later)
Kcj = Kc / 8760 = 0.005854 (Expression 10)
It is shown by the history of the period representative polymerization degree (for example, the final value every 10 days, the final value every month, etc.) based on the daily degree of polymerization, which is the daily final value of the calculated degree of hourly polymerization.

  In FIG. 3, the gradient Ky of the broken line 22 indicating the expected transition of the degree of polymerization after the current time is the average value of a plurality of gradients on the current day and several days ago.

  The gradient Kt of the two-dot chain line 23 indicating the estimated decrease in polymerization degree after the current time in FIG. 3 is calculated by means after the above-mentioned second insulating paper temperature calculating means.

  The number of years until the degree of polymerization that decreases due to the predicted gradient Ky or the estimated gradient Kt reaches the life judgment value is determined as follows: Is divided by the estimated gradient Ky or the estimated gradient Kt.

  When the deterioration display is performed from the middle of the operation of the transformer that is already in operation, and there is an insulating oil temperature history from the start of operation to the current time, the insulating paper temperature Tz is sequentially calculated by the first insulating paper temperature calculating means. In the absence of the insulating oil temperature history, the hourly polymerization degree at the current time is calculated by the calculating means after the second insulating paper temperature calculating means from the installation place temperature history and the operating load factor history. 5 enters the process flow after the storage in the hourly polymerization degree storage section and the next hourly polymerization degree calculation.

  For the transformer to be diagnosed, the degree of polymerization according to another life diagnosis method or the review degree of polymerization due to overcurrent flow, etc. is shown. After that, the process flow after the storage in the hourly polymerization degree storage unit in FIG.

  FIG. 4 is a configuration diagram showing the configuration of a transformer deterioration status display device according to an embodiment of the present invention, in which a data collection unit 51 that collects transformer insulation oil temperature, a polymerization degree calculation unit 52a, and a future polymerization degree calculation. A calculation processing unit 52 having a unit 52b and a remaining life calculation unit 52c, a polymerization degree storage unit 53, a graph creation processing unit 54 for generating a polymerization degree history graph, a display unit 55 for displaying a polymerization degree history graph, It comprises a setting unit 56 that gives the rated current of the diagnostic transformer, trial calculation conditions, and the like, and a control unit 57 that gives the date and time.

  FIG. 5 is a flowchart showing the processing process of the transformer deterioration status display device according to the present invention. From the data acquisition unit 51 that acquires the insulation oil temperature, operating current, etc. of the transformer to be diagnosed, it is classified according to time. The degree of future polymerization is calculated from the storage unit 53 that stores the calculated degree of polymerization for each time and the degree of polymerization for each period by time. A plurality of time-dependent polymerization degrees and a plurality of due-date polymerization degrees are transferred to the unit 52b, and a processing flow from the polymerization degree transition graph creation processing unit 54 to the display unit 55 is shown.

  FIG. 6 is a graph showing the relationship between the number of years of operation and the average degree of polymerization described in JEM 1463-1993 “Evaluation criteria for average degree of polymerization of insulating paper for transformers” in FIG. 4, and among the data group envelopes shown in the graph The solid line on the higher degree of polymerization corresponds to the degree of polymerization under the best use conditions in the present invention.

  Figure 7 is a graph showing the relationship between the number of years of operation and the degree of polymerization described in the manufacturer's technical document (January 1997, Hitachi Technical Note, Transformer Edition “Aging deterioration of oil-filled transformers”). Among the lines shown, the straight line with the maximum gradient corresponds to the degree of polymerization in the worst use condition in the present invention.

  Fig. 8 is a table of surveys of transformer load factors by industry published in Japan (April 2002, Japan Electrical Manufacturers' Association, General Energy Research Committee, Transformer Judgment Standards Subcommittee Survey Results). The load factor 290 data described as per day is quoted in the load factor range for calculating the degree of polymerization in the present invention.

  FIG. 9 is an example of published data regarding the temperature rise of the insulating oil and the windings with respect to the load factor of use of the transformer, and is an example of the graph shown in Japanese Patent Application Laid-Open No. 2001-291626 and FIG.

A ・ ・ ・ Insulating oil temperature rise during rated operation
C: Ratio of insulating paper temperature to insulating oil temperature in reference condition Ta ... Tac of installation location of diagnostic transformer Tac ... Reference temperature of transformer installation location Tp ... Insulation paper at rated operation Temperature difference with insulating oil Tat ... Temporary transformer installation location temperature
Tm: Insulating oil temperature rise value when no load To: Insulating oil temperature during operation
Toc: Insulating oil temperature Tz under the reference usage conditions ... Insulating paper temperature Tzc during operation ... Insulation paper reference temperature Tzs under reference usage conditions ... Insulation paper temperature during operation and insulating paper reference temperature Insulating paper temperature difference Tzst ... Insulating paper temperature difference between the insulating paper temperature and the reference insulating paper temperature in the trial calculation conditions I ... Operating current U of the diagnostic transformer ... Load factor Uc ... Reference load factor
Ui ... Virtual load factor Ut ... Trial load factor K ... Degradation degree actual gradient Kc ... Degree of polymerization decrease reference gradient Kcj ... Degree of polymerization degree decrease per hour Ky ... Polymerization Estimated degree of decrease in gradient Kt ... Estimated slope of decrease in polymerization degree R ... Gradient correction factor Jh ₂ ... Degree of polymerization at current time Jh ₁ ... Degree of polymerization 1 hour before current time ... Minimum gradient Degree of polymerization decrease straight line 1b ... Maximum gradient degree of polymerization decrease straight line 1c ... Intermediate gradient degree of polymerization decrease straight line 21 ... Change in degree of polymerization until the current time 22 ... Change in expected degree of polymerization after the current time 23 ... Change in degree of polymerization after current time under trial calculation conditions 30 ... Long-term display graph 31 of transformer degradation status ... Short-term display graph 50 of transformer degradation status ... Transformer degradation status display device 51 ... Data acquisition unit 52 ... Arithmetic processing unit,
52a... Polymerization degree calculation unit 52c ... Remaining life calculation unit 52b ... Future polymerization degree calculation unit 53 ... Storage unit 54 ... Graph creation processing unit 55 ... Display unit 56 ... Setting unit 57 ... control unit

Claims (1)

A transformer degradation status display device that shows the degradation status of a transformer by a decrease in the average degree of polymerization (hereinafter abbreviated as polymerization degree) of insulating paper, wherein the degradation degree standard gradient Kc is expressed as a standard usage condition of the transformer ( The insulation paper temperature at the installation location reference temperature Tac (one of 6 to 18 ° C.) and the reference operation load factor Uc (one of 10 to 70%)) is continuously maintained at the insulation paper reference temperature Tzc and the reference use conditions. Polymerization in which the gradient of the degree of polymerization when operated is reduced at a gradient of any one of 10 / year to 60 / year from the degree of polymerization at the start of transformer operation (one of 800 to 1000) In the diagnostic transformer in which the degree of polymerization straight line is defined as the degree of polymerization lowering reference slope Kc and the operating state changes, the degree of polymerization lowering slope correction coefficient R (hereinafter referred to as the slope correction coefficient R) calculated in relation to the operating conditions is used. The degree of polymerization lowering standard gradient Assuming that the degree of polymerization decreases by an actual gradient K multiplied by Kc, the gradient correction coefficient R is set to an insulation paper temperature difference Tzs which is a difference between the insulation paper temperature Tz during operation and the insulation paper reference temperature Tzc under the reference conditions. R = 1 / exp (−H × Tzs), (where H is one of 0.06 to 0.14 (1 / ° C.)), and the diagnostic transformer a first data acquisition means for acquiring the insulating oil temperature to, and either or both of the data acquisition unit, the second data unit that acquires location temperature Ta and the operation current I of the diagnostic transformer, said first 1 having the data acquisition means 1, the 1-a approximate expression of the insulating paper temperature Tz with respect to the load factor U Tz≈Ta + Tm + U ^y × (A + Tp−Tm), where Ta is the temperature of the transformer installation location, Tm is the absolute value when there is no load The oil temperature rise value, A is the temperature rise value of the insulating oil during rated operation, Tp is the temperature difference between the insulating paper and the insulating oil during rated operation, and the virtual load factor calculation formula Ui≈ ( (To-Ta-Tm) / (A-Tm)) A 1-a insulating paper temperature calculating means for calculating the insulating paper temperature Tz at the insulating oil temperature To by substituting the load factor of ^{(1 / x)} , 1-b approximate expression of the insulating paper temperature Tz with respect to the insulating oil temperature To Tz≈C × To (where C is the insulating oil temperature of the insulating paper temperature Tzc according to the approximate expression of the 1-a in the standard use condition) The 1-b insulating paper temperature calculating means for calculating the insulating paper temperature Tz at the insulating oil temperature To by the approximate expression To≈Ta + Tm + U ^x × (A−Tm) (ratio to the insulating oil temperature Toc), and the second data For those with acquisition means Te, a second dielectric sheet temperature to calculate a first 1-a substituting to insulating paper temperature Tz to the approximate expression of the acquired be diagnosed transformer operating current the insulating paper temperature load factor U divided by the rated current a calculation unit, the first 1 -a, as the difference between the insulating paper reference temperature Tzc in calculated insulating paper temperature Tz and the reference operating conditions by any of the first 1-b or the second insulating paper temperature calculating means, The insulating paper temperature difference Tzs is calculated, the calculated insulating paper temperature difference Tzs is substituted into the calculation formula of the gradient correction coefficient R, the gradient correction coefficient R is calculated, and the calculated gradient correction coefficient R is used as the reference gradient Kc. Means for multiplying to calculate the actual gradient K of the gradient reduction, means for storing the degree of polymerization by time and the degree of polymerization by date of the degree of polymerization reduced by the actual gradient K in a degree-of-polymerization storage unit, and a plurality of times before the current time Multiple gradients used to calculate the degree of polymerization Based on the means to calculate the future degree of polymerization decrease expected gradient after the current time as an average value and the trial calculation conditions (transformer trial installation location temperature and trial load factor) input from the input unit, the above degree of polymerization degree reduction gradient Means for calculating a future degree of polymerization degree decrease estimated gradient in the trial calculation conditions according to the calculation means, read from the polymerization degree storage unit, polymerization degree transition from the start of use of the diagnostic transformer to the current time, and the current time Degree of future polymerization degree predicted transition along future expected degree of polymerization degree decrease and future degree of polymerization degree estimated transition after current time along said degree of polymerization degree estimated gradient from the start of use of diagnostic transformer for several decades Means for displaying in the long-term polymerization degree transition graph until, or means for displaying in the long-term polymerization degree transition graph, or the short-term polymerization degree transition graph around several days starting from the long-term polymerization degree transition graph and the present time Simultaneous display or transformer deterioration state display apparatus characterized by comprising means for alternating display, the a.

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