Primary
Where relatively high-voltage primary feeders (23-kV and above)
operate in metallic sheathed cables and are rather long, the capacitance
effect of the cable may cause undesirable voltage rises along the feeder.
Reactors connected between the primary conductors and the neutral or
ground are inserted in the feeder at appropriate points to hold customer
voltages within permissible limits; shunt reactors act in a similar fashion
as shunt capacitors.
Secondary
Where two or more transformers supply a common load, the transformers
may not share the load equitably. This may be due to differing
secondary voltages at the transformers’ terminals either because the
primary feeder voltages are different, or because the transformers have
different impedances. Reactors inserted in the secondary leads of one or
more of the transformers are installed in an effort to equalize the voltages
and make the transformers share the load equitably.
This phenomenon is often evident in low-voltage secondary networks, and especially
in “spot networks.” In this latter case, the terminals of the reactor coil of
one transformer are interconnected to those of another transformer with
the leads reversed. Hence, the voltage drop in each of the reactances is
added to or subtracted from the several secondary voltages, tending to
balance the load among the several supply transformers.
