3. • An electrical substation is a subsidiary
station of a transmission and distribution
system where voltage is transformed from high
to low using transformers.
• Electric power may flow through several
substations between generating plant and
consumer, and may be changed in voltage in
several steps.
4. It is an automatically-operated electrical
switch.
It operates both on “ON LOAD” and “NO
LOAD” conditions.
5. The protective relay ensures the safety of
the circuit equipments from any damage
which might otherwise cause by fault.
6. It is connected between the line and earth so
diverts the incoming high voltage wave to
earth.
Lightning arresters act as safety valves
designed to discharge electric surges
resulting from lightning strokes, switching
or other disturbance .
8. Bus-bars are merely convenient means of
connecting switches and other equipment
into various arrangements.
9. THERE ARE TWO TYPES OF BUS :-
1.Main bus
2. Transfer bus
10. A switch is used in an electric circuit as a
device for making or breaking the electric
circuit in a convenient way
11. The control room is nerve center of a power
station .
The various controls performed from here
are voltage adjustment, load control,
emergency tripping of turbines etc.
12.
13. A transformer is a device that
transfers electrical energy from one
circuit to another through inductively
coupled conductors-the transformer's
coils.
Types:-
1. STEP-UP
2. STEP-DOWN
14. A transformer is a static device which
transfers a . c. electrical power from one
circuit to the other at the same frequency
but the voltage level is changed
15. Power Line Carrier Communication, is an
approach to utilize the existing power lines
for the transmission of information.
16. The communication device used for the
communication over the power lines is a MODEM,
commonly known as Power Line MODEM (PLM).
It works as both transmitter and receiver, i.e., it
transmits and receives data over the power lines
17. It collects three primary types of data .
1.the status of process devices (digital inputs)
2. measures process variables (analog inputs)
3.accumulators (pulse inputs).
18. RTU database can be downloaded on
operator request, from a PC using the
SIM900 software.
The software package delivered with S900
RTU allows to handle both digital and
analog inputs/outputs
