SCADA Systems

Monitoring and Control of processes are implementedof various sub-station oriented displays in several
using SCADA systems. SCADA is an acronym forcomputer consoles. The sub-station oriented displays
Supervisory Control and Data Acquisition. Variables ofin several computer consoles. The sub-station level
a process are constantly monitored and processeddata acquisition such as status of CB's, disconnectors,
for computation of various parameters for issue of/ isolators and analog values such as MW, MVAR, Hz,
control commands, if necessary, in both open andKV, Amps etc. are first captured with the help of
closed loop manner with the help of a combination ofrespective interfacing elements in the RTU.Master
electromechanical and digital elements/equipments.Thestation scans the RTUs either on cyclic fashion or on
implementation of fairly large SCADA system used inpoll-by-exception method. Depending on the
applications like power system monitoring and control,communication channel that exists between Master
involves a centralized process computer connectedand RTU's, the exchange of data between the
to a large number of Remote Terminal Units (RTUs)Master and RTUs are implemented using either
which are geographically distributed in vast areas,analogue or digital communication media. The
using efficient communication channels. The processCharacteristics of transfer of data between Master
computer acquires intelligence from these remoteand the RTUs is typical of a Master/ Slave protocol,
terminal units and does the necessary processingin a SCADA system. There exists a variety of
internally with the help of numerous applicationdifferent types of Master/ Slave protocols that are
software programs that are executed in theimplemented in a SCADA system. Most of these
computer either on demand basis.The Power systemprotocols in the past were only supporting analog
Dispatchers are responsible for the dispatchcommunication channels. However, with the advent
operations like, issue of supervisory controls to eitherdigital communication technology, getting migrated to
open or close Circuit Breakers (C.Bs) in substation,digital SCADA protocols like IEC60870-104 protocols
lower or raise the scheduled interchange of powersupported using digital communication media. This
with the neighboring power systems, to maintainwould also support an RTU talking to more than one
system parameters like voltage, frequency, powerMaster Station.Praise is the Professor and Head of
flow, to monitor and analyze various system alarmsthe Dept of
as well as to take appropriate actions against eachInformation Technology of
alarm etc.In order to enable the Dispatchers to doCalicut University. with more than 25 years of
these functions, they are provided with a completeProfessional Experience in
snap-shot of the entire power system with the helpUniversity of Calicut.