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Field Training Report On TCD, Bengaluru: Telephone Communication Division (TCD)

The document summarizes a field training report on the Telephone Communication Division (TCD) in Bengaluru. It discusses that TCD was established in 1966 to coordinate within the Karnataka Electricity Board and is divided into North and South Zones. It then provides details on the functions of TCD, how telephones work, the functions of telephone exchanges, Power Line Carrier Communication (PLCC) systems, and the components and advantages of PLCC. The document concludes by declaring that the authors visited TCD, Bengaluru on December 20, 2018 as part of their pre-employment field training.

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Navaneeth Nair
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130 views2 pages

Field Training Report On TCD, Bengaluru: Telephone Communication Division (TCD)

The document summarizes a field training report on the Telephone Communication Division (TCD) in Bengaluru. It discusses that TCD was established in 1966 to coordinate within the Karnataka Electricity Board and is divided into North and South Zones. It then provides details on the functions of TCD, how telephones work, the functions of telephone exchanges, Power Line Carrier Communication (PLCC) systems, and the components and advantages of PLCC. The document concludes by declaring that the authors visited TCD, Bengaluru on December 20, 2018 as part of their pre-employment field training.

Uploaded by

Navaneeth Nair
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Field Training Report on TCD, Bengaluru

Date: 20.12.18

Telephone Communication Division (TCD):


 Established on 11.02.1966 for co-ordination within Karnataka Electricity Board (KEB).
 TCD divided into two Zones :
o North Zone (Hubli)
o South Zone (Bangalore)
 Activities of TCD
o To provide private automatic branch Exchange in KPTCL
o PLCC
o SCADA
o Video Conference

Telephone:
 The sound waves converts into electrical waves in the transmitter and sends over the
line
 The received electrical signal converts into sound signal in the receiver.
 The dialer section gives Pulse or tone signal to the telephone exchange to select the
required dialed number.
 Ringer section gives audible alarm. Whenever, telephone receives the A.C ringing
voltage from the telephone exchange.

RINGER
DIALER
LINES
TRANSMITTER RECEIVER

Function of Exchange:
 The exchange has to give a tone to a subscriber to make him to know that the phone
is ready for dialing (dial tone).
 After completion of dialing process, the subscriber has to get a tone to know that the
called subscriber is ringing (ring back tone) or the subscriber is busy (busy tone)
 If it is ringing on A.C. voltage of 55 to 75, 25 cycles has to be sent to called party.
 After lifting the handset of the telephone of the called party, exchange has to cut the
ringing supply and to make through the speech path between the subscribers.
 After completion of the calls between the subscriber, the whole exchange has to
come to normal and ready for the next operation.
 There are some other features like: transfer of calls, auto call back, call pick-up etc.

Power Line Carrier Communication (PLCC):


PLCC system uses the same high voltage transmission line connecting two
substations for telecommunication purpose. PLCC is used in all power utilities as a primary
communication service to transmit speech, telemetry and protection tripping commands.
This is economic and reliable for inter-grid message transfer as well at low bit rate RTU
signals.
The voice/data are wired with radio frequency (40-500KHz) amplified to a level of
10-800 RF power and injected into high voltage power line using a suitable coupling
capacitor.

BLOCK DIAGRAM OF PLCC


Power Line
Wave Trap

Coupling
Capacitor

Line Matching
Unit (LMU)

RTU PLCC Terminal

Components:
PLCC terminal: Translates Voice and Data into high frequency carrier, output power=10 to
80W.
LMU (Line Matching Unit): For Impedance matching between line and co-axial cable,
include high voltage protection device like Drainage coil (20mtrs), lightening arrestor (500v)
and an earth switch.

Coupling Capacitor: Couples high frequency carrier with power line (4000 to 10000 pF).

Wave Trap: Do not allow transmitted high frequency carrier to enter inside the substation.
Without Line Trap high frequency carrier get by-passed to some other line on the same bus
bar and may leak to ground.

Advantages of PLCC:
No separate wires are needed for communication purposes, as the power lines
themselves carry power as well as communication signals, hence the cost is less. Carrier
protection with relaying of transmission line so that, inter-trip command can be issued by
relay due to tripping of circuit breaker at any one end

Declaration:
We, Tejashwini S, Guruprasad E, Avinash MV and Manjunath VB Assistant Engineers
(Elec.), KPTCL have visited the TCD, Bengaluru on 20.12.18 for field training organized by
HRDC KPTCL, Hoody in accordance with pre-employment training for the newly recruited
Assistant Engineers(Electrical).

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