JP2016051458A - Selection method of power transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To estimate and select the lifetime improvement effect and the profit conversion life regarding a various types of power transformers including the capacitances different from the existing power transformers when the power transformers are renewed.SOLUTION: With respect to the number of update candidate transformers including capacitances different from the existing power transformers, a loss improvement effect (life saving money amount and life CO2 emission weight loss) and a profit conversion life (update investment amount/lifesaving power rate) are collectively displayed according to a magnitude (0 to 100%) of a load factor of the existing power transformers, and the estimation of the update effect in the various types of the load factor taking a review of the load distribution into consideration is performed taking the usable load factor upper limit of the update candidate power transformer into account, and the power transformed optimal for updating is selected by the life profit of each candidate transformer in the selected use load factor.SELECTED DRAWING: Figure 6

Description

  The present invention relates to selection work at the time of transformer update, and for various update candidate transformers having different capacities from existing transformers, the transformer loss improvement effect by update while considering the usable load factor region (update transformer) (Estimated lifetime saving electricity charges, lifetime CO2 reduction amount, etc.) and renewal transformer cumulative profit (accumulated savings minus renewal investment cost) It relates to the technology to select reliably.

  Transformers that have been in use for a long time as new transformers as a countermeasure against aging due to thermal deterioration of insulation paper between transformer windings and between transformer windings and transformer cores At this time, as an energy-saving measure for saving energy resources, it is being promoted to upgrade a transformer incorporating a transformer loss reduction measure.

When updating a transformer, the annual loss of the transformer at the operating load factor is calculated for each of the existing transformer and several types of candidate transformers. Transformer annual loss = (No load loss + (Usage load factor / 100) ² x load loss at rating) x 24 x 365 ··· Formula (1)
(Here, the load factor used is the load load capacity (kVA) / transformer capacity (kVA) x 100 (%))
Calculated by, existing transformers and converted into improving effect due to loss difference between each update candidate transformers (annual savings power rate and annual emissions CO ₂ reduction amount) and the recovery period (transformer replacement investment costs / year savings electricity rate) Thus, a method of selecting a transformer having a large improvement effect by comparing and evaluating is employed.
JP-A-2005-348507

  In the conventional transformer renewal study, the annual loss of each transformer is calculated for the existing transformer and several types of renewal candidate transformers by the above formula (1). Compared with the improvement effect due to the transformer loss difference, a method of selecting a transformer having a large improvement effect is employed.

In Patent Document 1, the annual power loss of the transformer obtained by multiplying the above formula (1) by the unit price of power charge. )
The loss of the existing transformer and each update candidate transformer according to the size of the load factor used (0 to 100%) is shown in a graph, and the transformer with the lowest annual power loss at the assumed load factor To choose.

  However, the selection graph shown in Patent Document 1 is limited to the type of update candidate transformer that has the same capacity and different loss characteristics as the existing transformer. I missed the vessel.

In cases where the load factor of the existing transformer is small, the transformer loss improvement effect due to the update or the transformer update for various types of transformers including transformers with smaller capacities than the existing transformer in order to reduce transformer costs. Consideration will be made to find the best investment cost recovery year, but when upgrading to a transformer with a smaller capacity than the existing transformer, the load capacity used is constant and only the transformer capacity becomes smaller, so the candidate transformer for the update It is necessary to consider that the usage load factor of the transformer increases, and for each update candidate transformer, the conversion use load factor of the update candidate transformer = the use load factor of the existing transformer x the transformer capacity ratio ... (Formula 3)
(Here, the transformer capacity ratio is the existing transformer capacity / update candidate transformer capacity)
While calculating the said Formula (1) and the said Formula (2) using,
Usable load factor upper limit of update candidate transformer Usable load factor upper limit of update candidate transformer = Usable load factor upper limit of existing transformer / transformer capacity ratio Equation (4) )
It is necessary to take the trouble of selecting the upper limit value of the usable load factor by calculating the maximum load factor, and it is necessary to eliminate the trouble of selecting the optimal transformer for the update or to save the effort. Overlooking the effect of transformer loss improvement and selecting the renewal transformer based only on the years of recovering the renewal cost of the transformer without checking the condition, it will be overlooked that it will be used at severe load factor and the life of the transformer will be significantly shortened There was a fear.

  In addition, although transformer renewal is an important measure for preventing accidents due to aging, short-term evaluations that place an order only by the number of years of recovery of investment costs related to renewal are emphasized. By giving priority to another energy-saving measure with fewer years, there was a risk that the transformer was not updated and an accident occurred due to transformer deterioration.

  The present invention has been made in view of such circumstances, and differs from the capacity of an existing transformer so that a wide range of evaluations can be performed in consideration of integration with neighboring transformers and review of load sharing in transformer renewal studies. Transformer loss improvement effect at various load factors for various transformers including capacities (lifetime saving electricity charges and lifetime CO2 reduction amount of renewal transformer) and profit conversion years (renewal investment cost of renewal transformer / year (Electricity savings) can be updated while checking the upper limit value of the usable load factor of each transformer, using a selection graph or selection table to evaluate various update candidate transformers at the same time. In addition to making it easy to narrow down transformers, the selection graph or selection table adopts the selected load factor (a wide range that also considers integration with nearby transformers and review of load sharing). Indicate the cumulative profit of each renewal candidate pressure generator calculated based on the existing transformer standard use load rate determined after a close examination (the amount obtained by subtracting the renewal cost of the transformer from the accumulated power savings) Can confirm the lifetime profit of the candidate transformer (the value of the accumulated profit in the expected number of years of use of the renewal transformer), and ensure that the long-term saving effect of the renewal transformer with a long service life can be evaluated. Therefore, the purpose is to contribute to ensuring preventive maintenance so that the aging update is carried out at an appropriate time without being postponed.

  In order to achieve the purpose of the previous term, the selection method according to claim 1 is configured such that the transformer loss improvement effect of the transformer and the profit conversion by the update are obtained for various update candidate transformers including different capacities from the existing transformer. Incorporating means that can recognize the usable load factor area or non-conforming load factor area of the update candidate transformer according to the magnitude (0 to 100%) of the load factor of the existing transformer, The selection graph or the selection table is characterized in that the accumulated profit (the amount obtained by subtracting the transformer renewal cost from the accumulated saving amount) for each renewal candidate transformer at the selected use load factor is described according to the years of use.

  According to the selection method of the present invention, according to the selection graph or the selection table, the improvement effect of the transformer loss and the profit conversion years in the various update candidate transformers are within the usable load factor region of each update candidate transformer. Therefore, it is possible to easily and efficiently narrow down candidate update transformers having a high improvement effect without error, so that an update candidate transformer having the largest lifetime benefit can be obtained by the lifetime benefit of each update candidate transformer at the selected load factor. It can be selected and it can be recognized that even a transformer with a small initial saving effect has a large improvement effect in the long term, and it is caused by deterioration of the transformer because it is implemented without aging update Accidents can be prevented.

Transformer annual power loss graph by load factor using conventional technology Transformer power loss graph for each existing transformer standard load factor according to the present invention Numerical input table for creating a selection table of the present invention Update transformer selection table according to the present invention Profit conversion years by standard load factor of existing transformer according to the present invention Life saving power charge graph by standard load factor of existing transformer according to the present invention Cumulative profit graph by age of renewal transformer according to the present invention

  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.

The tables or graphs from FIG. 2 to FIG. 7 are woven into the update transformer selection program read from the storage device of the optimum update transformer selection computer to the processor of the computer, and the numerical input table shown in FIG. Is the transformer capacity, no-load loss, rated load loss, transformer replacement investment cost, unit price of electricity, CO ₂ emission factor, planned years of use of the existing transformer and the existing transformer When the upper limit value of the usable load factor of the transformer is entered, the data transfer function provided in the update transformer selection program enters the numeric value column for each applicable transformer in the update transformer selection table shown in FIG. The input value is transferred.

The update transformer selection table shown in FIG. 4 shows the improvement effect of each update candidate transformer including the capacity different from that of the existing transformer and the profit conversion year of the load factor of the existing transformer (0 to 100%). ) The annual loss calculation formula of the update candidate transformer in which the load factor in the formula (1) is replaced with the update candidate transformer conversion load factor to be compared in a batch. = (No load loss + (Update candidate transformer equivalent load factor / 100) ² ) x 24 x 365 Equation (5)
Annual saving electricity charge calculation formula Annual saving electricity charge = (annual loss of existing transformer-annual loss of renewal candidate transformer) x electricity charge unit price ... Formula (6)
And profit conversion years calculation formula profit conversion years = transformer renewal investment cost / annual savings formula (7)
Life saving amount calculation formula Life saving amount = Annual saving amount x Expected years of use of renewal transformer ... Formula (8)
For each transformer, the input values (transformer capacity, no-load loss, rated load loss, transformer renewal investment cost, unit price of electricity charge, CO ₂ emission factor, number of years of planned use of renewal transformer And the usable load factor upper limit value of the existing transformer), the lifetime saving power charge of each transformer, the lifetime CO2 reduction amount (not shown), and the profit conversion years of the update transformer are the update candidate transformers. Calculated for each unit and displayed collectively on the load factor standard of the existing transformer, and the update candidate conversion use load factor of the formula (3) is indicated on the line corresponding to the existing transformer load factor, and the update candidate For rows where the transformer-converted use load factor exceeds the upper limit value of the usable load factor of the transformer entered in the input table shown in FIG. 3, each transformer loss, lifetime saving amount and lifetime emission CO2 in the selection table are as follows. Reduction amount (not shown) and profit change A means is provided in which a value other than a numerical value (UD in the example of FIG. 4) is written in the conversion year column.

In the selection table shown in FIG. 4, the cumulative profit calculation formula calculated based on the adopted use load factor is: cumulative profit = cumulative power loss for existing transformer−cumulative power loss for update candidate transformer−update of transformer Investment cost (Formula 9)
(Here, cumulative power loss = annual power loss x years of use)
Is accumulated, and the cumulative profit of each candidate replacement transformer at the adopted load factor determined after various load factor considerations is indicated by the years of use.

  FIG. 5 is the profit conversion years graph of the update transformer created from the update transformer selection table shown in FIG. 4 by the graphing means incorporated in the update transformer selection program, and each update candidate transformer is used as a parameter. It represents the number of years of profit conversion according to the load factor (0 to 100%) of the existing transformer. By setting the horizontal axis as the standard load factor of the existing transformer, it is possible to represent the graph collectively including transformers with different capacities from the existing transformer, and the load exceeding the usable load factor of each update candidate transformer The rate of profit conversion in the rate area is not expressed by means that does not display a part that is not a number in the update transformer selection table of FIG. 4 provided in the graphing means.

FIG. 6 is the lifetime saving amount graph of the transformer selection table shown in FIG. 4 by the graphing means incorporated in the update transformer selection program, and the load factor of the existing transformer is large with each update candidate transformer as a parameter. This represents the lifetime saving amount according to the amount (0 to 100%). By setting the horizontal axis as the standard load factor of the existing transformer, it is possible to represent the graph collectively including transformers with different capacities from the existing transformer, and the load exceeding the usable load factor of each update candidate transformer The lifetime saving amount in the rate area is not expressed by means that does not display a portion that is not a number in the update transformer selection table of FIG. 4 provided in the graphing means.
FIG. 7 is a graph showing the cumulative profit (equation 9) in the adopted usage load factor of the update transformer shown in FIG. 4 by the graphing means incorporated in the update transformer selection program, and each update candidate transformer is a parameter. The horizontal axis is displayed collectively as the years of use of the renewal transformer.
(The lifetime profit of each update candidate transformer is the cumulative profit when the horizontal axis is the expected number of years of use.) (Transformer whose update transformer equivalent use load factor exceeds the usable load factor upper limit at the adopted use load factor Is excluded from the illustration)

  FIG. 2 is a loss power comparison graph of each transformer based on the existing transformer load factor according to the present invention, and only the load factor region where the existing transformer and each transformer can be used is graphed.

Claims (1)

In the selection related to the update of the existing transformer, the existing transformer is added to the update transformer selection table or the update transformer selection graph incorporated in the update transformer selection program read from the storage device of the optimal update transformer selection computer to the processing device. The transformer loss is calculated by using the load ratio obtained by multiplying the capacity ratio of the transformer and the update candidate transformer, and the existing transformer and each update candidate transformer are updated for various update candidate transformers that have different capacities from the existing transformer. improved due to the loss difference between the vessel effect (life saving power rate and lifelong discharged CO ₂ reduction amount) benefit conversion period (investment cost / year savings electricity pricing updates transformer), conversion using load factor update candidate transformer For areas that exceed the upper limit value of the existing transformer's load factor, the size of the load factor of the existing transformer (in a way that can be recognized as an unsuitable zone or not in a graph) 0 to 100%) and the selected usage load factor (based on the existing transformer standard determined after evaluation taking into account integration with nearby transformers and review of load sharing) Selection of update transformers equipped with a means to indicate the cumulative profit of the update transformer calculated based on () the cumulative savings amount minus the transformer upgrade investment cost) according to the years of use of the update candidate transformer A method for selecting a renewal transformer, characterized by using a table or a renewal transformer selection graph.

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