Abstract:
Chapter I deals with the relay elements and
comparstors used in modern protective relay schemes- Phase
and amplitude comparators using transistors, rectifiers and
Hall multipliers are reviewed in brief.
Chapter II deals with the development of polyphase
relay schemes. It gives the development of polyphase
relays an^ reduction of distance relay and directional relay
in protection schemes in brief, polyphase distance
relay using phase comparison and polyphase distance relay
using amplitude oomparison have been discussed in more
detail.
Chapter III deals mainly with the author's own
work in the field of static polyphase distance relay scheme.
Two schemes are developed ( l) based on the principle of
phase comparison (2) based on the principle of phase
sequence measurement by logic circuits. The first was found
unsatisfactory therefore the second scheme has been
described in detail as regard to its characteristic on
single phase to-ground, ph as e -t<j -phase and double phaseto-
ground faults. Two schemes have also been proposed to
protect the line against 3 -phase faults.
Chapter IV deals with the experimental set up of
the scheme based on the principle of phase sequence measure
ment. Two similar units wore developed in order to avoid the
over-reaching of the relay on d.c, transient in the fault
current.
Chapter V gives the experimental results on steady
state and dynamic performance of the relay under fault condi
tions on positive as well as negative transients
