2.3.2.4
Influencing Factors. The number of individual loads in a group and
their load factors influence the individual load coincidence factor. The
coincidence factors in Table 8 apply for groups of l00 or more individual
loads. These coincidence factors can also be used for groups of as few as 30
to 50 individual loads if their load factor is 0.30 or greater. For areas of
fewer individual loads, the mathematical relationship from IEEE Technical
Paper 45-116 provides a basis for estimating the connected coincidence factor
as shown by the following equation:
2.3.2.5
Individual Loads. The coincidence factors in Table 8 are based on
the individual loads in a group being substantially the same size. If a
single load or small group of loads in an area represents a substantial
percentage of overall load, the coincidence factors as given in Table 8 will
no longer apply. With an individual load, increase the coincidence factor to
a value commensurate with its effect on the overall area load. This is not
in addition to, but in place of, the normal coincidence factor. Determine
this value by considering intergroup coincidence factors given in paragraph
2.3.2.6. (An example of facility Navy code 211-70 is presented in Table 7.)
For a small group, determine the coincidence peak load, and to this apply
the appropriate intergroup coincidence factor to obtain the coincidence peak
load for the area.
2.3.2.6
Groups of Loads or Areas. Where groups of loads within an area, or
areas within a facility are combined, an additional intergroup coincidence
factor will exist. For loads of a similar nature, the intergroup coincidence
factor should be in the range 0.93 to 1.00. If loads of a varying nature
(evening loads and daytime loads) are combined, the intergroup coincidence
factor should be in the range of 0.70 to 1.00. The lower values will occur
when the magnitudes of the loads are nearly balanced, and the higher ones
when the combined load is predominantly one type.
2.3.3
Load growth. In addition to planned expansion, increased
application of electric equipment will generate an increase in load. When
sizing components, such as transformers or feeders for the area system,
consider possible load growth in addition to that included in the
determination of individual loads.
2.3.4
System Losses. Add distribution system losses to estimated area
demands.
For a good approximation, use 6 percent of the calculated maximum
demand.
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