2. INTRODUCTION
WHAT IS SCADA??
SCADA (supervisory control and data acquisition system) refers to the
combination of telemetry and data acquisition. SCADA encompasses the
collecting of the information via a RTU (remote terminal unit), transferring it
back to the central site, carrying out any necessary analysis and control
and then displaying that information on a number of operator screens or
displays.
SCADA system consists of one or more field data interface devices ( RTUs
or PLCs).A communication system such as radio, telephone, cable,
satellite,etc. A central host computer sever or severs (also called a SCADA
center, or Master Terminal Unit (MTU)).
3. COMPONENTS OF SCADA
The SCADA system usually consists of the following subsystems:
• A Human–Machine Interface(HMI) is the apparatus or device which
presents process data to a human operator, and through this, the
human operator monitors and controls the process.
4. • A supervisory (computer) system, gathering (acquiring) data on the process
and sending commands (control) to the process.
• A remote terminal unit (RTU) is a
microprocessor-controlled electronic
device that interfaces objects in the
physical world to a distributed control
system or SCADA (supervisory control
and data acquisition) system by
transmitting telemetry data to a master
system, and by using messages from the
master supervisory system to control
connected objects.
THERE ARE BASICALLY TWO TYPES OF RTU:
Single Board RTU.
Modular RTU.
5. • A programmable logic controller, PLC or programmable controller is a
digital computer used for automation of typically industrial
electromechanical processes, such as control of machinery on factory
assembly lines, amusement rides, or light fixtures. PLCs are used in
many industries and machines.
• Communication infrastructure connecting the supervisory system to
the remote terminal units. Various process and analytical
instrumentation
6. WORKING OF SCADA
A SCADA system for a power distribution application is a typically a PC-
based software package. Data is collected from the electrical
distribution system, with most of the data originating at substations.
Depending on its size and complexity, a substation will have a varying
number of controllers and operator interface points.
Data from the PLC and the devices is then transmitted to a PC-based
SCADA node located at the substation.
Ethernet-based and are implemented via the Internet, an intranet
and/or some version of cloud computing.
12. CONCLUSION
SCADA provides management with real-time data on
production operations, implements more efficient control,
improves plant and personnel safety, and reduces costs of
operation.
The government of India has decided to integrate all the
state power utilities. Unified load dispatch Centre has to be
build. So automation has lot more advantages as it
increases efficiency and increase standardization.
Single board - Which is compact, and contains all I/O on a single board. The single board RTU normally has fixed I/O (eg.16 digital inputs, 8 digital outputs, 8 analogue inputs, and say 4 analogue outputs).
Modular RTU- which has a separate CPU module, and can have other modules added, normally by plugging into a common "backplane" (a bit like a PC motherboard and plug in peripheral cards) is designed to be expanded by adding additional modules.
In a typical configuration, a substation is controlled and monitored in real time by a Programmable Logic Controller (PLC) and by certain specialized devices such as circuit breakers and power monitors. Data from the PLC and the devices is then transmitted to a PC-based SCADA node located at the substation.
One or more PCs are located at various centralized control and monitoring points. The links between the substation PCs and the central station PCs are generally Ethernet-based and are implemented via the Internet, an intranet and/or some version of cloud computing.