Book review
93
Protective
Relay
Principles
by Anthony F. Sleva
Power system protection is a
very complex subject that requires
good understanding of the electric
power system components and the
different abnormal conditions that
can occur as a result of a short circuit
fault or equipment failure. The
changing technology and evolving
protection principles are additional
factors that require people working
in the field to continuously work on
expanding their knowledge.
The author of the book ,
Anthony Sleva, has many years as
a protection engineer in the relay
section of System Operations,
Pennsylvania Power & Light
Company. This practical experience,
as well as his teaching of protection
courses at Lehigh University and
the University of Wisconsin has
helped him write an excellent
introductory book on the principles
and applications of protective relays
in electric power systems.
The material in the book is
presented in 350 pages, divided in
twenty chapters. The first chapter
covers the primary components of
the electric power system, such as
transmission and distribution lines,
transformers and breakers, buses
and generators. The second chapter
focuses on subcomponents of the
primary equipment (instrument
transformers, bushings, insulators,
switches, etc.) and secondary
equipment (protective relays,
programmable logic controllers,
batteries, etc.). The next chapter
describes different abnormal system
conditions – short circuit faults,
overloads, abnormal voltage and
frequency conditions, unbalanced
and
open phase
conditions. It is
followed by a chapter
introducing the concept
of sequence components and
the calculation of currents and
voltages in the cases of different
short circuit faults. The following
two chapters discuss the basic
protection functions and how they
can be combined to provide more
advanced fault detection.
Zones of protection and
the types of protection relays –
electromechanical, solid-state
and microprocessor based – are
presented later in the book,
followed by setting and protective
relay coordination considerations.
A significant portion of the book
is dedicated to the protection of
distribution lines – both radial and
networked. Protection philosophy,
the use of different phase and
ground overcurrent relays and
the criteria and methods for their
settings calculation are presented in
an easy to understand manner with
many practical examples.
Transmission line protection
and transformer protection are
just briefly introduced to give an
idea to the reader about the basic
issues and the principles of their
protection. The same is also true
for the chapters on bus and breaker
failure protection, capacitor bank
and reactor protection. The last
chapter of the book covers issues
related to the protection of the
electric power system in case
of abnormal conditions such as
voltage and frequency variations
caused by a system disturbance.
Under and overvoltage protection,
as well as under and overfrequency
protection and their applications are
briefly described.
Overall, this is an excellent
book for beginners in the field of
electric power systems protection,
especially due to the focus on
the pract ical aspects of the
application of protective relays to
detection and clearing of abnormal
system conditions. The multiple
step-by-step examples will help
the reader understand and become
comfortable with the methods for
calculation of system parameters and
the settings of the different types
of relays. The fact that the book
describes not only the individual
protection functions, but also how
a programmable scheme logic can
be use to improve and optimize
the protection of distribution or
transmission networks is something
that will help grasping some of the
more advanced principles used in
modern protection devices and
systems.
Protective Relay Principles
by Anthony F. Sleva
Publisher: CRC Press - Taylor & Francis Group
ISBN 978-0-8247-5372-6
PAC.MARCH.2010