Generator Peaking Application (SCP 250-G)

In peaking generator applications, the paralleling circuit of a voltage regulator presents large changes in

reactive current when the bus voltage changes by a relatively small amount. However, the regulator’s

ability to compensate for large changes in bus voltage can be exceeded. Two examples illustrate typical

problem areas.

Example 1. A generator equipped with a voltage regulator adjusted for 4% droop can

have a variation in var load from zero to 100% with a 4% decrease in bus voltage.

Further decreases in bus voltage would overload the generator.

Example 2. An increase in bus voltage can cause leading power factor conditions with

the associated danger of the machine pulling out of synchronization.

To minimize the possibility of either example occurring, the SCP 250 is used and adjusted for operation in

a “safe” region with either a regulated “fixed” var level or a “fixed” power factor. Thus, for a large change

in reactive current due to bus voltage changes, the operating generator is unaffected.