Page 784 - Basic Electrical Engineering

Percentage regulation at full load 0.8 power factor leading

This shows that regulation is negative at 0.8 leading power factor load.

This is because the full-load terminal voltage is more than the no-load
voltage.

10.14 SYNCHRONOUS GENERATORS CONNECTED IN PARALLEL TO SUPPLY A COMMON
LOAD

Due to a number of advantages, a group of alternators are installed in the
power house instead of a very large single unit. For example, instead of

installing a 1000 MVA alternator, we may decide to instal five 200 MVA
alternators and connect them in parallel to supply common load. There are a

few advantages of parallel connection and operation of number of alternators.

10.14.1 Advantages of Parallel Operation

i. If instead of one very large alternator, a number of smaller units are installed, it is possible to
switch off any alternator for repair and maintenance without disrupting the power supply
completely.
ii. Additional sets can be added depending upon the need.
iii. It may not be possible to build generators for very high capacity, i.e., the capacity of a power
plant. For example, a thermal power plant near Talwandi Sabo in Panjab is being set up to
generate 1980 MW. A single alternator of such a high capacity may be physically difficult to
construct and transport to the site.
iv. Alternators connected in parallel can be operated near to full load rather than running a big
alternator on low load when the demand for electricity changes.

10.14.2 Parallel Connection of Alternators