CHH

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INTRODUCTION TO PLCC

NAVED KHAN

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INTRODUCTION TO PLCC

PLCC stands for power line carrier communication , power line carrier communication has been found to be the most economical and liable method for communication medium and long distance in power distance

Power line carrier communication is the technology which is used to communicate between electric substations through existing electrical cables.

Power line tele communication is mainly used for tele communication ,tele-monitoring and tele-protection between electric substations through power line at high voltages.The data can be transfer at 9.6kbits/sec over many miles of electrical cable.

BASIC PRINCIPAL OF PLCC

In plcc the higher machnical strength and insulation level of high voltage power line result in increasing reliability of communication and lower attenution over long distance.

Since telephone communication system can not be directly connected to high voltage lines, suitable designed coupling device have to be employed.

Carrier curret used for communication have to be prevented from entering the power equipment used in gss as this would result in complete loss of power system.

CC/CVT CHARACTERISTIC

It is connected between the line matching unit and the power line to block the high voltage entering to the plcc equipment.

It couples the high frequency carrier with power line.

DETAILS OF WAVE TRAP AND LINE TRAP

WAVE TRAP;- It is 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 crcuit connected to the same power station.

It also enure proper operating conditions and signal

level at the plcc transmit receive equipment irrespective of switching condition of power circuit and equipment in the station.

A wave trap must satisfy the following requirement :

1. It must block the carrier current.By blocking,we mean that the the track should attenuate the H.F signal at least to 8 to 10 db.

2. It must carry the power frequency current safely during normal operation as well during short circuit fault conditions.

CIRTUIT DIAGRAM OF WAVE TRAP

Over view of telemeteing systemTelemetry is a technology that allows data measurements to be made at a distance.[1] The word is derived from Greek roots: tele = remote, and metron = measure. Systems that need external instructions and data to operate require the counterpart of telemetry, telecommand.

Although the term commonly refers to wireless data transfer mechanisms (e.g. using radio, hypersonic or infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like phase line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. The process of telemetry starts with data obtained from various sensors called transducers. These are thedevices which translate physical data such as temperature and pressure into electrical signals.In the simplest telemetry system, which monitors only one such transducer, the signal from the transducermay be applied directly to a radio transmitter (or sent directly over a cable). At the other end of the radiolink, the signal goes directly from the receiver to a suitable display device or recorder. For example, if thetransducer is monitoring temperature, the information may be displayed on a meter calibrated directly in degrees. A telemetry system is rarely called upon to monitor only one transducer. In general, the number of datasources is great and a separate transmission link for each one is not practical. Therefore, most telemetrysystems combine the signals from a number of transducers into a single composite signal fortransmission over one radio link. The process of combining these signals is called multiplexing, and eachindividual signal occupies a channel in the multiplex system.At the receiving end, the channels are separated by a process called demultiplexing and routed to the

various display or recording devices. The accompanying figure shows a basic telemetry system block diagram.

DETAILS OF EXCHANGE MDX 50

MDX-50 is used to form private networks or PLCC type of networks with similar type of exchanges. This system comes with a proven digital non-blocking technology. The MDX-50 is  cost effective high performance communication system. MDX-50, a digital EPABX, built around the 8-bit microprocessor Z80A, employs TDM-PCM technology with a fully non-blocking switching network. High system reliability is insured by automatic on-line diagnostics. The software is highly structured and a clear interface exists between hardware and software. It can be connected to P&T central office trunk. It can support E&M.

 

FEATURES

48 Subscribers / 16 trunks.

Stored program control.

Interface with PLCC, E&M, CO trunks, E&M Networks.

Non blocking switching networks. Modular in construction.

Flexible Directory scheme, Direct outward dialing.

Pulse / DTMF dialing.

Transmit call, Trunk grouping, Alternate routing.

Four party conference, Inbuilt self diagnostics.

Music on Hold

Easy data entry through Telephone.

DIAGRAM OF EXCHANGE MDX 50

EQUIPMENTS THERE ARE TWO TYPES OF EQUIPMENTS

a.Input equipment.b.Output equipment.

Outdoor equipment Indoor equipment

It consist of wave trap or line trap.

it consist of plcc parameters or plcc cabinet.

It consist of cc/cvt capacitor It consist of exchange i.e EPAX

It is used in 132 kv substation EPAX are used in 48 v d.c battery charger.

Example of out door equipment are LMU, LMDU

Example of indoor equipment are battery set.

INDEX INTRODUCTION TO PLCCPLCC SYSTEMEQUIPMENTS OF PLCCDETAILS OF WAVETRAPCC/CVT CHARACTERISTICSDETAILS OF EXCHANGE

MDX 50.OVERVIEW OF TELEMETRY.