Power Line Carrier CommunicationTO FROM:PROF.RAVI SONI PREETESH KUMAR ARYA(PROF.,EE DEPARTMENT) (IV YR,EE)

Contant

Training overview Company profile Introduction General modulation principle Basic principle of PLCC Specification Basic arrangement Wave trap Tuning capacitor Battery charger

Technical specification Maintanance and fault traction Maintanance and fault traction procedure applications Advantages disadvantages Key learning Conclusion

Training overview

Name of industry : Rajasthan Rajya vidyut prasaran nigam limited

Location : 220KV BASNI GSS , Jaipur

Duration of training : 20 may to 11 july

Department of training : electrical engineering

About company

RRVPNL started working from july 1957 Sh.shailendra Agarwal,IAS is the chairman & MD of RRVPNL RVPN provides the pathway for power within whole rajasthan This is the body of big organization ACT, like public limited

companies It works as electric power distribution regulation within the state.

Introduction

PLCC, Power Line Carrier Communication, is an approach to utilize the existing power lines for the transmission of information.

This technology has been in wide use since 1950 and was mainly used by the grid stations to transmit information at high speed.

Can use existing infrastructure for data traffic

Involves a lot of technicalities.

General modulation principle

Single side band transmission

Carrier frequency is spaced on a 4KHz

I.F. fixed at 16KHz

Full duplex mode is used

Lower side band is used throught all communication

Basic principle of PLCC

The communication system cannot be directly connected to the high voltage lines suitably designed coupling devices.

These usually consist of high voltage capacitor with polaritical devices used in conjucation with suitable line matching unit (LMU) for matching the impedence of line to that of the coaxial cable connecting the unit of the PLC transmit-receive equipment.

Specifications of PLCC

1) GENERAL:- Carrier frequency range:-40 to 512KHz Useful AF band:-300 to 3700Hz

2) TRANSMITTER:- Peak envelope power:-25W Side band power:-15W

Basic arrangement

The basic arrangement of connecting the WT and coupling capacitor in PLCC communication is shown in figure

Types of coupling

A) phase to ground coupling

Phase to phase coupling

Phase to phase coupling

INTERLINE OR INTER CIRCUIT COUPLING

Wave traps

Wave traps – (WT’s) are used between the transmission line and the power stations to avoid carrier power dislocation in the power plant and cross talk with other power line carrier circuits connected to the same power station

Tuning capacitor

For lower voltage class of tuning units with impulse test voltage rating upto 40 KV polystyrene capacitors are used

For higher voltage class of tuning units with impulse test voltage rating upto 150 KV, capacitors with mineral oil impregnated paper dielectric are used

Used are high voltage, high stability mica capacitors with low losses

Battery charger

PLCC (Power Line Carrier Communication) works on rectified AC or main power supply. When supply goes off, we use BATTERY CHARGER for proper functioning of PLCC, which provides supply to the PLCC equipment for uninterrupted working. It provides DC to the panel by battery of 48V. In this type 24 batteries are connected in series and individually per battery has approximately 2V capacity.

  Battery charger mainly consists of 4 sections –   1.    Float charger 2.    Boost charger section 3.    Control section 4.    Alarm section

Technical specifications

NORMAL INPUT :415 V AC 3-PHASE INPUT VARIATION : +/- 20%

FLOAT CHARGER : DC OUTPUT :50 V OUTPUT CURRENT :20 TO 40 AMP EFFICIENCY : >70%

BOOST CHARGER DC output - 43.2 to 67.2 V Output current - 25-70 Amps. Efficiency - >80%

Maintanace & fault traction

Fault analysis: in fault analysis the faulty devices are checked in this serial or manner:

1. Telephone or tele operation signal2. Cabling low frequency circuit or DC power supply3. PLC equipment4. HF transmission path

Maintainance and fault traction procedure

The control circuit boards should be inserted far firmly.

The charger should be switch off once in every month.

The battery terminal should be connected first and AC input after that.

All mounting bolts should be checked before energizing.

Applications

PLCC Unit Provide Five type of operation:

1:TELEPHONE FACILITES2:COMPRESSOR & EXPANDER3:EMERGENCY CALL4:SIGNAL BOOSTING5:SUPERVISION & ALARMS

Advantages

No separate wires are needed for communication purpose. Both communication and power transfer can be possible on same

circuit Power lines provides the shortest route between the power

station Increase reliability Lower attenuation over long distance Implementation cost is reduced

Disadvantages

Reflection are produced on spur lines connected to high voltage line this increased attenuation and create other problem.

High voltage lines have transformer connections,which attenuate carrier currents.

Noise introduced by power lines is far more than in case of telephonic lines.

Proper care has to be taken to guard carrier equipment and persons using them against high voltages and currents on the lines.

Key learning

PLCC is mainly used for telecommunication,tele-protection and tele-monitoring,between electrical substation through power lines.

In a PLCC system the communication is established through the power line.

The carrier frequency range is allocated to include the audio signal, protection and the pilot frequency.

conclusion

Power line carrier communication has been found to be the most economical and reliable method for communication in a medium and over long distance in a power system.

Questions?

Thank you