20-01-2016, 04:00 PM
INTRODUCTION
The idea of using an existing medium to send the communication signals is as old as the telegraph itself. But it had not been possible until the recent decades. The first significant step in the field was when two patents were issued to American Telephone and Telegraph Company in the name of 'Carrier Transmission over Power Circuits' in 1920. After four years later in 1924 two other patents were filed for the systems transmitting and receiving communication signals over three phase power lines.Harsh characteristics of the power cables were the key problem in further development. Researchers were involved to overcome the unpredictable characteristics of the power lines.Since the early 1980, spread spectrum power line com -munication was the main focus of the research. This technology is now developed far better than that initial improvement and is promising a reliable utilization in home automationand security systems.Fast and efficient communication is a pre-requisite for the management of modern power systems. To maintain a large power grid in optimum working condition the Central Load Despatcher has to have his command a large battery of communication systems. The lead despatcher may use the commercial PIT telephone system using open wires or under-ground Cables for communication over short distances such as communications between the load despatch centre and generating/receiving stations in the same city. Where the load despatch station is located. In some cases, VHF wireless-communication, may also be used. For communication over medium and long distances in a power network , Power Line CarrierCommunication is the most economical and reliable method of communication
COMPONENTS OF PLCC :-
Carrier-:
The carriers used in modern plc communication system are audio frequency current of frequency in between 24 khz and
500 khz .
Modulation-:
In plcc technology the carrier currents are modulated by voice frequency .currents and modulated currents are transmitted
over the power line . frequency modulation is rarely used for speech transmission because of its considerable bandwidth
requirements.
ASIC ELECTRONIC COMPONENTS :-
1. resistor
2. capacitor
3. diodes
4. transistor
5. relays
6. switches
7. basic IC's
8. bread boarding of ckts
MODES OF COUPLING TO POWER LINES :- power transmission lines have usually three conductors , one for phase , running between point to point . this presents many different configuration for coupling to carrier equipment.
(a) phase to ground coupling
(b) two-phase coupling
© phase to phase coupling
(d) inter-phase coupling
APPLICATIONS OF PLCC :-
PLCC technology can be deployed into different types of applications in order to provide economic networking solutions. Hence
merging with other technologies it proves useful in different areas. These are few key areas where PLC communications are utilized:
a. Transmission & Distribution Network: PLCC was first adopted in the electrical transmission and distribution system to transmit information at a fast rate.
b. Home control and Automation: PLCC technology is used in home control and automation. This technology can reduce the resources as well as efforts for activities like power management, energy conservation, etc.
c. Entertainment: PLCC is used to distribute the multimedia content throughout the home.
d. Telecommunication: Data transmission for different types of communications like telephonic communication, audio, video communication can be made with the use of PLCC technology.
e. Security Systems: In monitoring houses or businesses through surveillance cameras, PLCC technology is far useful.
f. Automatic Meter Reading – Automatic Meter reading applications use the PLCC technology to send the data from home meters to Host Central Station.