Page 778 - Basic Electrical Engineering

on the generator changes, it will give rise to difficulties in operations of
various electrical machines and gadgets connected to the system. Voltage
regulation tells us about the health of the machine in terms of its voltage

stability.
Voltage regulation is defined as the percentage change of the terminal

voltage from its no-load condition to its full-load condition as a percentage of
full-load voltage. Thus,

The phasor diagram of Fig. 10.11 (a) is redrawn to calculate voltage

regulation at a lagging power factor load.
From Fig. 10.12

2
2
2
2
AG = AK + KG = (AD + DK) + (KC + CG) 2
2
2
or, E = (AB cos ϕ + I R ) + (AB sin ϕ + I X ) 2
a a
a s
2
2
or, E = (V cos ϕ + I R ) + (V sin ϕ + I X ) 2
a a
a s
or,