POWER LINE CARRIER COMMUNICATION

ETLETL

LTLT

C CFAX

FAX

PR PC MS PAX FAX

M DC

PR PC RTU FAX

M

C = Coupling DeviceDC = Dispatcher's consoleFAX = Facsimile equipmentLT = Line trapM = Modem

MS = Master stationRTU = Remote terminal unitPAX = Private automatic exchangePR = Protection relayPC = Computer

PLCC

CVT

STATION A STATION B

ESLMU

PLCCPROTECTIONCOUPLER

EXCHANGE

CVT

ES

EXCHANGE

PLCC

LMUPROTECTIONCOUPLER

LA

DC

WT

DIRECT COUPLING OF THE PLCC EQUIPMENT TO THE POWER LINE.

1.To provide effective isolation for the PLCC equipment and the user from the power frequency (50hz) voltages of the order of a few 100’s of kv of the power line.

2.To provide a least impedance path for injecting the h.f. signal (30 to 500khz) to the power line, by providing effective impedance matching between the power line and the PLCC equipment for maximum transfer of power of the h.f. signal.

3.To ensure enough h.f. signal strength on the power line between Tx & Rx signal injection points, irrespective of the switching conditions of the power system beyond the either end of the power line.

PLCC CONSISTS OF A) INDOOR EQUIPMENT

PLCC TRANSRECEIVER, TELEPHONE X’ge,DATA MODEM,PROT

COUPLER, RTU Etc. B) OUTDOOR EQUIPMENT LINE MATCHING UNIT,CVT,WAVETRAP C) COAXIAL CABLE interconnects I/D and O/D Equipments.

OUTDOOR EQUIPMENT WAVETRAP CAPACITOR VOLTAGE TRANSFORMER LINE MATCHING UNIT PROTECTIVE DEVICES -EARTH SWITCH

- LIGHTNING ARRESTOR

CAPACITIVE VOLTAGE TRANSFORMER CVT IS CONNECTED BETWEEN THE LMU

AND THE POWER LINE. THIS IS USED TO BLOCK THE EHT LINE

VOLTAGE ENTERING INTO THE LMU/PLCC AND ALSO FOR METERING / POTECTION OF THE POWER LINE .

IT IS A STACK OF CAPACITORS CONNECTED IN SERIES WITH ONE END CONNECTED TO POWER LINE AND ONE END GROUNDED.

THE CAPACITANCE OF CVT IS 2200 / 4400 / 8800 PF.

LINE MATCHING UNIT

LMU CONSIST OF AN IMPEDANCE TRANSFORMER WHICH MATCHES THE IMPEDANCE OF LINE WITH THE COAXIAL CABLE IMPEDANCE

CC

LINE PLCC

IMP TRANSFORMER

WAVE TRAP CONSIST OF MAIN COIL TUNING CIRCUIT LIGHTNING ARRESTOR ALLOWS ONLY 50 HZ SIGNAL AND

OFFERS HIGH IMPEDANCE TO HIGH FREQUENCY SIGNAL BAND SPECIFIED BY TUNING CIRCUIT

WAVE TRAP SHALL BE DESIGNED TO CARRY THE FULL LOAD CURRENT OF THE POWERLINE.