Minimum Distribution System Concepts and Applications

Weighted Linear Regression
For Distribution Line Transformers
m
=
[ N×
∑nXY] − [ ∑nX×
∑nY]
2
[ N×
nX ] − [ nX] 2
∑
SLOPE
∑
N = Total number of all transformers of
a given type, e.g., 59,800 7.2 kV -
120/240 V, single-bushing, polemount
units
n = Number of a given size transformer,
e.g., 9,935 15 kVA
b
y-INTERCEPT
⎡ ⎤
∑nY
⎢∑nX
= − m×
⎥
N ⎢ N ⎥
⎣ ⎦
X = Transformer size in kVA, e.g.,
5, 7.5, 10, 15, etc.
Y = Transformer unit cost in $ per unit,
e.g., $724.48 (cost of a 15 kVA unit)
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