Unit 5

CONTROL CENTERS AND POWER SYSTEM SECURITY

VOLTAGE STABILITY

Receiving end voltage, current and power as a function of load demand.

The current and voltage is given by

SCADA CONCEPTS• Input/output signal hardware, controllers, HMI,

networks, communication, and software.

• Site control is actually performed automatically by a remote terminal unit (RTU) or by a programmable logic controller (PLC).

HUMAN MACHINE INTERFACE

Presents process data to a human operatorPresents process data to a human operator

Through which the human operator controls the process Through which the human operator controls the process

HARDWARE SOLUTIONS

Distributed Control System (DCS) components IEC 61131-3, is frequently used to create programs which run on these RTUs and PLCs.

Allows SCADA system engineers to perform both the design and implementation of a program to be executed on a RTU or PLC.

SYSTEM COMPONENTS

• Multiple Remote Terminal Units (also known as RTUs or Outstations). To physical equipment, and reads status data such as the

open/closed status from a switch or a valve, reads measurements such as pressure, flow, voltage or current.

Has alarms ---Can be activated based on the requirements.

• Master Station and HMI Computer(s). Servers and software responsible for communicating with

the field equipment (rtus, plcs, etc) Master station may be SINGLE or MULTIPLE SERVERS

SCADA prsents a information as a MIMIC diagram Mean Time Between Failures Is Very Low• Communication infrastructure Used Radio And Direct Serial Or Modem Connections To

Meet Communication Requirements Ethernet and IP over SONET--- railways and power stations COMMUNICATION PROTOCOLS-----Modbus, RP-570 IEC 60870-5-101 or

104, Profibus and DNP3

FUNCTIONING OF SCADA SYSTEMS

Channel scanning Polling

Interrupt Scanning

Conversion into engineering units

Data processing

EMS AND SCADA

LOAD MONITORING SYSTEM using SCADA

ADVANTAGES

Easy identification of area of fault occurrenceEffective monitoring of utilization of loadDistance between MASTER STATION &RTU can

be very longAccurate decision making is possibleMimic diagram representation is possibleHigh reliability (less mean time between failures)