is 13241-1 (1991): code of practice for installation and

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IS 13241-1 (1991): Code of practice for installation andmaintenance of indoor PLC equipment, Part 1: PLC terminals[LITD 10: Power System Control and AssociatedCommunications]

IS13241(Part1):1991

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Indian Standard

INSTALLATION AND MAINTENANCE OF INDOOR PLC EQUIPMENT-CODE OF

PRACTICE PART 1 PLC TERMINALS

UDC 621’3’052’63 : 621’372’512

0 BIS 1991

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

October 199 1 .

Price Group 2

Power Line Carrier Systems and Associated Telecontrol Equipment Sectional Committee, LTD 25

FOREWORD

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Power Line Carrier Systems and Associated Telecontrol Equipment Sectional Committee had been approved by the Electronics and Telecommunication Division Council.

This standard ( Part 1 ) is one of a series of standards on Code of Practice for Indoor PLC Equipment. Other parts likely to be brought out under this series shall cover equipment like teleprotection equipment, protection signalling channels, etc.

Indian Standard

IS 13241 (Part 1 ) : 1991

INSTALLATION AND MAINTENANCE OF INDOOR PLC EQUIPMENT-CODE OF

PRACTICE PART 1 PLC TERMINALS

1 SCOPE

1.1 This standard ( Part 1 ) covers installation and maintenance of PLC terminals used as indoor equipment.

4.1.1 It is recommended that PLC terminal is installed only after the carrier room is fully ready for use.

4.1.2 Carrier Room

2 REFERENCES

2.1 The Indian Standards given below are necessary adjuncts to this standard:

IS No. Title

3043 : 1987 Code of practice for earthing

9482 : 1980 Characteristic values of inputs and outputs of single side band PLC terminals

10706: 1983 Methods of tests for single side band PLC terminals

4.1.2.1 The carrier room should be well illumi- nated and there should be provision of ac supply socket which will be used for feeding, the testing instruments ( during commissioning or subsequent line-ups ). If there are a number of PLC terminals in the carrier room, a minimum working space of 1’5 m should be provided between adjacent rows of cabinets. This space is required for keeping the testing instruments on a work-bench,

4.1.2.2 Supply to each PLC terminal should be given through distribution board with separate fuse/cutout.

3 TERMINOLOGY

3.1 For the purpose of this standard, the defini- tions given in IS 9482 : 1980 shall apply.

4 INSTALLATION

4.1.2.3 Most essential spares, such as fuse/cutout of correct rating and size transistors, KS, LEDs and supervisory alarm lamps should be stored such that they are readily available. This would definately keep the downtime of the equipment to minimum.

4.1 General and Carrier Room The following points should be obeserved when installing PLC terminals in carrier room:

a) PLC terminal rooms should be clean and dust free;

NOTE -The carrier room should be preferably air conditioned.

4.1.2.4 The essential plug-in units and test/ measuring instruments should be available at a centrally located store. Certain plug-in-modules and test/me

& ring instruments should be available

in individu substations as per manufacturer’s recommendations.

b) The room should be well ventilated with air at a temperature of 15 to 35°C and RH of 43 to 75 percent;

c) The cabinet of the PLC terminals should be preferably mounted on plinths about 75 mm high;

d) A suitable covered cable duct should be provided. Where it is not possible to provide a cable duct, the height of the plinth should be suitably raised to accommodate the connecting cables; and

4.1.2.5 The relevent documentation, interconnection diagrams, cable schedule, commissioning test results and subsequent alignment test results should be readily available in the PLC room.

4.1.2.6 For easy maintenance, it is reccommended that a suitable distribution frame is used for terminating subscriber lines in the Carrier Room and for interconnection of the same with the switching equipment/PAX, etc.

The distribution frame should consist of fuses, lightning arrestors in each of the subscriber lines for the protection of the equipment as well as the user.

a) Wherever cable entry is from the top, cables may be carried on aerial cable tray.

4.1.2.7 Only authorized persons should have access to PLC terminals used for teleprotection.

1 .

IS 13241 ( PnrC 1 ) : 1991

4.2 Cabinets

4.2.1 The cabinet with hinged-frame design may be directly located against the wall or back-to- back. Cabinets which have doors at the back should have adequate clearance from the wall for inspection.

4.2.2 For external connections, reference should be made to the wiring diagrams of the PLC terminals. Cabling should be done systematically for quick checking and tracing. Identification marks on cables would help in fault location.

4.2.3 The packing provided during transport should be removed. It should be checked whether all prints/modules ( as per face plan ) are in position; and the circuit boards should be plugged in the correct locations according to manufacturer’s face plan.

4.3 Supply Connections

If in the carrier room, a number of PLC terminals are present, supplies should be given to each cabinet through distribution boards.

4.4 ‘Checks

The following checks should be made before commissioning tests on PLC terminals:

a) Check if supply connections have been made according to diagram;

b) Check the voltage and capacity of the float charger, if terminals are dc powered,

C) Check if the cross section of the cable is adequate; and

d) Check whether protective earthing to the equipments has been provided in accordance with IS 3043 : 1987.

4.4.1 After these preliminary check&ommission- ing tests on PLC terminal may be started.

4.5 Earthing

4.5.1 For earthing conductors protected against corrosion, the minimum cross-sectional area of earthing conductor shall be 16 mm2 of copper or iron. For earthing conductors not protected against corrosion, the minimum cross-sectional area of earthing conductor shall be 25 mm* of copper or 50 mme of iron.

4.5.2 In addition to protective earthing telecommunication systems may require functional earths for any or all of the following purposes:

a) To complete the circuits of telegraph or telephono systems employing on-earth path for signalling purpose;

b) To eirth the power supply circuit and stabilize the potential of the equipment with respect to earth;

c) For lightning-protective apparatus; and

d) To earth Ecreening conductors to reduce electrical interference to the telecommunication circuits.

The functional earthings as per 29.1 and 29.2 of IS 3043 : 1987 shall be provided.

4.6 If PLC terminals are connected in parallel on CF side, separate connecting point should be used. Further care should be taken to match the output impedance of PLC terminal to the impedance of the carrier frequency line.

5 STORAGE OF PLC TERMINALS

The manufacturer recommendations with regard to conditions and period of storage should be adhered to.

6 MAINTENANCE OF PLC TERMINALS

6.0 In general, all routine checks should be carried out to ensure that all operating voltages/currents, levels for various services, Automatic Gain Control Characteristic, AGC, etc, are as per manufacturer’s recommendations and comply with the provisions of relevant Indian Standard.

6.1 Routine Maintenance

Under normal circumstances, the following routine checks should be carried out at interval of 3 months:

a) Check voltages of power supply to be within limits according to IS 9482 : 1980. If possible, these should be brought to the normal values.

b) On the transmit side, distribution of power between speech and signals should be checked for compliance with IS 9482 : 1980. It is important that HF amplifiers is not overloaded, otherwise there would be risk of intermodulation products.

c) On the receive side, it should be checked that PLC terminal is working in the middlo of AGC range.

d) The input and output levels of both speech ( test tone ) as well as signals should be checked for compliance with IS 9482 ; 1980.

6.2 Annual Maintenance

The installation should be systematically aligned and levels adjusted once a year and this job should be attended to by qualified personnel conversant with the equipment. tn this alignment, special

2

IS 13241( Part 1 ) : 1991

attention should be paid to the distribution of power between speech and signals as well as to VF response within the entire effectively trans- mitted speech and signals frequencies. Moreover the line-up should be done by using suitable measuring/testing instruments ( see Annex B of IS 10706 : 1983 ).

6.3 Fault Rectification

6.3.1 For fault location, the guidelines given in the instruction manual provided by the PLC terminal manufacturers may be followed. 6.3.2 The fault may be located with the use of suitable test/measuring instrument and rectified by replacing the faulty units. 6.3.3 In the case of faults of serious and persistent nature, it may be necessary to realign the complete channel.

6.3.4 A major change in level may require complete realignment of the PLC channel ( both transmitter and receiver ). It should also be ensured that the change in AGC is not due to defect in the outdoor coupling equipment or any possible change in transmission line configuration etc. Any such major re-arrangement in the line configuration should be taken up only after due consideration to the functioning of the PLC channel.

6.3.5 Record should be kept of the test results at the time of commissioning and subsequent line- ups of the PLC channels.

6.4 Schedule of Maintenance

A recommended schedule of of PLC maintenance terminals is given in Annex r1.

ANNEX A

( Clause 6.4 )

RECOMMENDED SCHEDULE FOR MAINTENANCE OF PLC TERMINALS

Details to be Checked Frequency of Checking Remarks

i) Measurement of various operating parameters by built-in facilities

ii) Functioning of speech channel

iii) Measurement of supply voltage iv) Cleaning of relay contacts

v) Alignment of PLC Link i) Pilot, and HF oscillators frequencies

and levels Half Yearly

ii) Carrier leak measurement Half Yearly iii) Sub-division of power in various sub-channels Half Yearly iv) Audio frequency response and equalisation Half Yearly v) Setting of automatic gain control Half Yearly

Weekly

Daily Daily As and when required

-

-

-

Exhaustive cleaning may be made under supervision of experienced persons

-

-

- - -

Standard Mark

The use of the Standard Mark is governed by the provisions of the Bureau oj Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark on products covered by an Indian Standard Conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by BIS and operated by the producer. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. Details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.

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BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director Publications ), BIS.

Revision of Indian Standards

Indian Standards are reviewed periodically and revised, when necessary and amendments, if any, are issued from time to time. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition. Comments on this Indian Standard may be sent to BIS giving the following reference:

Dot : No. LTD 25 ( 586 )

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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