How line reconductoring affects distribution line loss?
Our basics in electrical study from the past taught us the relationship between conductor resistance and conductor size. We’ve learned that conductor resistance is inversely proportional to the cross-sectional area of the conductor and directly proportional to its length. This means that for a given same type of material, when the conductor’s cross-sectional area increases, its resistance will decrease proportionally. While if the conductor length increases, its total line resistance will also increase proportionally.
Distribution line loss are computed using the I^2R formula regardless whether it is a primary or secondary line or any line in particular. Understanding this formula allows us to also understand how losses in the line exist which will later help us in reducing this losses.
Different sizes of conductors like ACSR each possesses different values of resistance in which all can affect the line loss it generates. Furthermore, different type of conductor material used will affect the same way. Having this in mind, boundless possibilities are available if one wishes to manipulate the conductors’ line resistance value.
With all these knowledge about the nature of conductor resistance, electric utilities innovatively include this idea as a method for line loss reduction for distribution system. Reconductoring distribution lines have been a widely accepted practice for line loss reduction.
By changing the conductor size, electric companies are able save on losses even if the lines are delivering the same amount of power to the customers. For example, the losses on 2/0 ACSR distribution line will be significantly less than that of the losses on a 336 ACSR line catering the same load.
Conductor size selection for optimum objective will most likely be based on loss considerations for distribution lines which are heavily loaded or for rural feeder trunk lines near substations. For lightly loaded lines extending for long distances, on the other hand, voltage drop constraints or load shift capacity requirements more likely will be the most important consideration in choosing conductor size.
Besides reducing the distribution line loss, reconductoring of distribution lines usually to a higher wire size becomes also beneficial for increasing the current-carrying capabilities of the distribution system. By upgrading the distribution lines, electric utilities are not only able to minimize the line loss but also increase the line capacity as well.
Like any other methods for distribution line loss reduction, economic considerations should always be studied. Line reconductoring projects involves monetary equivalents in which the company must incur like cost of material, labor cost, lost of revenue due to interrupted customers and other factors involving cost related to the project.
Also, if the whole purpose of the line reconductoring is for loss reduction, it should always be look into whether the loss savings obtained from this project can justify the cost involve in upgrading the line in the long run.
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