Brief Description of the Set-Up and Activities of the Power and Telecommunication Coordination Committee (ptcc)

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Chapter I
Brief Description of the Set-Up and Activities of the

Power and Telecommunication Coordination Committee (PTCC)

  1. Introduction

The importance of the co-ordination between power and telecommunication lines in India was brought to the forefront by the increasing number of situations of parallelism experienced immediately after independence. It was felt that, with further progress in the development plans for electric power and telecommunication, there would be a continually increasing number of such cases.

Both the power and communication engineers gave considerable thought to the subject and it was taken up for discussion in the All India Power Engineers Conference held in New Delhi in February 1949. It was recognized that the subject involved considerable amount of specialized study and that the task of finding solutions to co-ordination problems that might arise from time to time as well as to evolve general co-ordination methods is better dealt with by a committee of Power and Telecommunication Engineers.

  1. Formation of the PTCC

The All India Power Engineers Conference held in February 1949 discussed the problems in considerable detail and recommended to the Central Government the formation of a Central Standing Committee for co-ordination of Power and Telecommunication Systems. The recommendation of the conference was given effect to in resolution No.EL.II-151 (7) dated at New Delhi, the 30th May 1949 from the Government of India, Ministry of Works, Mines and Power, amended by corrigendum No.ELII-157 (7) dated 29th August 1949. The Resolution is reproduced as Appendix I to Chapter I.

  1. Functions of the Committee

3.1 The terms of reference and the functions of the Committee are indicated in detail in the circular letter dated 19th September 1949, issued by the erstwhile Ministry of Works, Mines and Power to the various State Governments etc. separately at Appendix II to Chapter I.

3.2 The Rules of Business of the Central Standing Committee for co-ordination of power and telecom lines adopted during the PTCC meeting on 24th March 1972 are reproduced in Appendix III to Chapter I.

  1. Membership of the Committee

4.1 The Committee initially consisted of 10 members representing the Central Electricity Commission, the then Post and Telegraph (P&T) Department, the

Electricity Branch of the Punjab, Public Works Department (PWD) and the Civil Aviation Directorate (Technical Officers) and the Ministry of Finance, the then Ministry of Works, Mines and Power and the Ministry of Communications. Although the Power & Telecommunication Coordination Committee (PTCC) was initially constituted for one year, the Ministry of Natural Resources and Scientific Research vide their Letter No. EL.II-15 (9) dated 15th February 1952 decided that it would continue to function until further orders. There have been some changes in the membership of the Committee from time to time. The co-option of members from the Railway Board in the PTCC was recommended by the 11th Plenary Session of the PTCC held in December 1965 in view of the large number of parallelism cases arising from the electrification of Railways. The Deputy Director (Telecom), Railway Board was then nominated to the Committee. A representative of the Wireless Adviser to the Government started attending the Committee meetings from 1961 onwards. Representatives of various State Electricity Boards took part in meetings of the Committee from 1967 onwards. The meeting of the Committee held in April 1975 recommended changes in the composition of the PTCC to make it more functional and the present membership of the Central PTCC is based on the Government of India, Ministry of Energy’s notification No. 3/1/2001 - Trans dated 11th April 2001 reproduced in Appendix IV to Chapter I.
4.2 The meeting held on 10th August 1973 suggested that the PTCC should hold meetings at the regional centers so as to ensure more effective participation and involvement by the State Electricity Board and local Committees thus enabling the members of the PTCC to have first-hand knowledge of the problems faced at regional levels. This was unanimously agreed to.

4.3 In the Central PTCC meeting held in Hyderabad in February 1977, it was decided to have these meetings on a quarterly basis covering all the four regions in a year and including the concerned representatives in each region. During discussions between Secretaries, Ministry of Energy and Ministry of Communications and their concerned officers held in New Delhi in May 1977, it was decided that a high level committee composed of Member, Telecom Board; Member, Central Electricity Authority (CEA); and other officers would be established to resolve important policy aspects and other pending matters of Power Telecom Co-ordination. A few meetings of the Committee have since taken place.

  1. Meeting of the PTCC

    1. The first meeting of the Committee was held on 28th and 29th June 1949, when certain decisions on the conduct of business of the PTCC were taken. It was decided to have two kinds of meetings, viz. Plenary and Technical.

Plenary Meeting
This would deal with constitutional, administrative and financial aspects of co-ordination work and ratify all resolutions of the Technical Meeting. All the representatives of the Ministries and the technical members would be present at these meetings.
Technical Meeting
This would deal with technical questions relating to co-ordination and communicate decisions in specific cases to the parties concerned. Any recommendations having repercussions on financial and legal matters would be referred to the Plenary Meeting.
The procedure for modifying any existing technical standard and issuing new technical directives was considered and it was decided that self-contained Committee Papers will be prepared in each case and circulated in advance to all members.
5.2 The Committee suggested that the principles in choosing a particular co-ordination method should be:

  1. On the basis of the least cost to the Country consistent with the proposed measures being technically sound and efficient.

  1. That the least cost will take into account the first cost as well as the capitalized value of recurring maintenance cost.

  1. That whether the remedial measures are carried out on the power line or communication line, the apportionment of costs as between the participating parties and Governments will be worked out in each case with due regard to the existing law and established practice.

    1. Ever since its inception to the end of 1971, there have been 23 Technical Sessions and 24 Plenary Sessions of the PTCC. Subsequent to 1971, combined meetings have been held and a total of 89 such meetings have taken place during the period from March 1972 to January 2009.

  1. Activities of the PTCC

A summary of the main activities of the PTCC is given below along with extracts of important decisions of the Committee topic wise for information.

6.1 Field Experiments, Studies and Reports
6.1.1 The first set of field experiments was carried out by the PTCC at Amritsar in 1949 on the 132 KV line between Jallandhar and Amritsar to determine the effects on the neighbouring Delhi-Amritsar carrier telephone lines. The tests were conducted with a view to determine the mutual coupling between the power and communication lines and the extent of shielding from induction afforded by the use of earth conductors. Tests were also conducted in Mumbai in November 1949 to study the interference from the 22 KV Kalyan – Vikhroli line of the Tata Power Company on the Kalyan – Mumbai trunk telephone lines. The tests were aimed at determining the shielding exerted by the electrified railway tracks paralleling the power and communication lines. The shielding effects of earthed conductors on a transmission line were experimentally studied in September 1950 on the 66 KV DC line from Coimbatore to Tirupattur. This test formed a part of the survey undertaken by the PTCC on the use of high conductivity wires for reduction of induction. The Committee published reports of the above tests.

      1. The Committee also published a report giving details of the methods of measurement of earth resistivity for the use of power and communication engineers in India, enabling them to choose, under given circumstances, the most practicable method for assessing the earth resistivity in any given area for purposes of interference calculations.

      1. The Committee deputed the two Joint Secretaries, Shri V.R. Raghavan (Power) and Shri B. Sivananda Rau (Telecom) to USA, Sweden, Canada, Switzerland and England in 1951 to make a joint study of the status of the problem of co-ordination between power and communication services in these countries. The object of the deputation was to study the principles and practices followed in those countries for mitigating the induction problem and to examine how similar problems can be tackled in India. After hearing the report of the Joint Secretaries, the PTCC passed a Resolution, at its meeting held in February, 1952 that although practices in / of foreign countries cannot be readily adopted in India, the Committee should make an intensive investigation to improve co-ordination practices in India and for this purpose, carry on systematic research work relating both to low frequency and noise induction. The Committee recommended to the Government that funds should be placed at its disposal as required for the purpose.

      1. Regarding soil resistivity values, the Secretaries reported to the Committee, in its meeting held in May 1953, that deduction of soil resistivity from induction tests showed close agreement with measurements made with earth testing meggar, provided the electrode spacing adopted for the latter were sufficiently high (150 feet or above) and the measurements were made at frequent intervals of the order of a mile.

      1. The Committee at the meeting held on 25th January 1974 adopted a Resolution recommending that a study team comprising representatives from the then Power Wing (PW) of Central Water & Power Commission (CW&PC) and P&T Department be sent abroad to study the latest techniques in regard to inductive co-ordination in other countries, since the last study team was sent more than 24 years back and in view of the considerable advances in other countries in the field. In the meeting held on 3rd September 1974, it was decided to include a representative from the Railways also in this Study Team.

      1. During the year 1978, a joint team of four officers from the CEA, the then P&T Department and Railway Board was deputed to Switzerland, France and Sweden to study the practices relating to co-ordination in those countries. The reports of the Study Team prepared separately by the Officers of the Central Electricity Authority/Railway Board and the then P&T Department were discussed so as to make suitable modifications where necessary in the existing Indian practices relating to PTCC.

      1. The PTCC at its meeting held in September 1978 appointed a sub-Committee consisting of representatives from the Central Electricity Authority (CEA), the then P&T and the Railway Board to go into the problem of interference to telegraph circuits from power lines. A copy of the recommendations of the sub-Committee is given at Appendix V to Chapter I. The important finding was that conversion of earth return telegraph circuits to metallic return is called for only when the interference current as computed exceeds 1/10th of the telegraph current. This recommendation has been accepted by the PTCC and clearances are being issued on this basis.

      1. A Sub-Committee was formed to study the noise due to paralleling power lines on telecom and railway communication circuits and in the meeting held on 29th October 1987, it was informed that the report of the Sub-Committee be circulated and in future noise problems should be sorted out directly by discussion among Central Electricity Authority (CEA), Department of Telecommunications (DOT) and Railways as required. The report of the Sub-Committee is given at Appendix VI to Chapter I.

      1. Effect of Single/Double phase power lines for railway traction purpose on paralleling communication lines was under discussion in Central PTCC. A Sub-Committee was formed to study the problem and suggest remedial measures. In the meeting held on 5th March 1992, it was informed by the Sub-Committee that there will be no electro-magnetically induced voltage due to normal working of these power lines but, however, each individual case would be given to PTCC clearance based on its merits.

    1. Codes of Practices

6.2.1 The Committee discussed the technical considerations involved in the transposition of power lines and the procedure adopted in various foreign countries and passed a Resolution to the effect (in its meeting in February 1952) that so far as interference to telecom lines is concerned, the transposition on power lines are not necessary.

6.2.2 The Committee, at its meeting held in February 1952 considered the regulations in regard to the structural arrangements to be provided at the crossing between power and telecom lines vis-à-vis the practices in some foreign countries and appointed a sub-committee to draft a suitable code. The draft submitted by sub-committee was considered in the meeting held in November 1953 and it was proposed that the draft suitably reworded be submitted to the Committee members for approval. In the light of the comments and information received regarding practices in other countries the draft code was revised and presented to the session held in March 1955. The Committee ratified the same for final printing and issue to all concerned. Revisions to the Code of Practice were made in 1963 and 1974. A copy of the present code is available in Chapter VI of this manual.

      1. In the meeting held in October 1963, the committee agreed to incorporation of the clause regarding the crossing of telecom lines with power lines having a pair of telecom lines on the same support in the PTCC Code of Practice.

      1. In the meting held on 8th March 1976 at New Delhi the matter regarding power line to be on one side of the road was discussed and it was agreed that in open country, where there are power or telecom lines, the first entrant could choose one side of the road. However, when next line is to be erected by the same party on the same route, it should as far as possible, be erected on the same side, where the first line existed. In case of difficulty, it may be sorted out between the power and telecommunication authorities by mutual consultation.

      1. A sub-committee was formed to finalize the norms for PTCC clearance of HVDC power lines. In the meeting held on 12th February 1987, it was decided that HVDC lines might be processed on the lines of norms finalized by the sub-committee. Actual observations would be taken when +500 KV Delhi – Rihand power line is commissioned and if necessary modification to the norms would be made. The norms for PTCC clearance of HVDC lines circulated vide CEA, New Delhi letter No. 19/117/87-PTCC dated 3rd February 1987 are at Appendix VII to Chapter I.

      1. Finalization of Code of Practice for laying of underground Power Cable in proximity of Telecom Cables was under discussion in Central PTCC and in the meeting held on 29th October 1987, it was decided to follow the recommendations based on the minutes of the meeting held between Delhi Electric Supply Undertaking (DESU) and Department of Telecommunication (DOT) on 23rd March 1987. These recommendations are given in Appendix VIII to Chapter I.

      1. In the meeting held on 14th June 1990, the draft Code of Practice on Earth Potential Rise (EPR) near sub-stations was approved and it is now included in Chapter VIII of this manual.

      1. In the meeting held on 16th February 1995 at Bhopal, it was reiterated that in principle the erection/ laying of lines by Power and Telecom authorities along road should be restricted to either side of the road to avoid close proximity.

    1. Protective Devices

      1. The installation of Gas Discharge (GD) Tubes was first proposed by the Committee on February1952 as a measure of protection of the telecom lines affected by induction. In its meeting held in September 1952, the Committee discussed the quotation received for GD tubes and the maintenance work involved in the use of GD tubes and the reliability of their performance. It was decided that

  1. The purchase of the tubes be expedited;

  1. The routine testing equipment for maintenance of GD tubes be purchased at the same time; and

  1. That a careful record of the performance of the tubes over a period of time be maintained.

      1. In the meeting held in March 1955, the Committee was informed that a trial consignment of NGC 3303 GD tubes had been received from M/s. Ericssons and that a limited number of short-circuit relay protectors used in America had also been obtained. These were to be tried in some known locations of severe induction. In the meantime, it was suggested that tests on these devices be conducted in co-operation with Indian Institute of Science. It was proposed that GD tubes be installed on telephone lines exposed to the Ganga canal grid lines and the SC relay protectors on the carrier alignment paralleling the Bangalore-Davangere 66 KV line. A detailed log of the faults on the power lines and the behavior of the protective devices on the telecom lines were suggested.

      1. The meeting held in January 1959 reviewed the investigations carried out at the Indian Institute of Science on the suitability and operational characteristics of various protective devices. The meeting held in February, 1960 considered the report of tests on protective devices further and recommended the uses of GD tubes in view of their suitability both as regard protective level as well as life as established by the tests.

      1. In the meeting held in February, 1961, the Chairman stated that it was very essential for the Telecom Department to carry sufficient stock of GD tubes since they were required in connection with cases of parallelism with power lines on which large sums of money were spent and the commissioning of which should not be delayed on account of lack of GD tubes for protecting the affected telecom lines. In the same meeting, the question of shortage of power contact protectors was also discussed and the Chairman wanted the Telecom Department to always keep sufficient stock of these protectors. In case of difficulty in finding adequate supplies of protectors, it should be permissible to adopt double guarding in order not to delay the energization of power lines.

      1. In the meeting held in October 1963, the Committee decided that the earth resistance for power contact protectors may be 10 ohms instead of 1 ohm or lower as decided earlier.

      1. The meeting held on 21st October 1972 expressed serious concern at the increasingly high levels of induction on telecom lines and strongly recommended that this problem should be studied in detail. Methods other than the provision of GD tubes, such as installation of sectionalizing transformers also deserved consideration.

      1. High voltage limit for protection with GD tubes was under examination and in the meeting held on 7th April 1983, it was intimated that instructions were issued to DEs (T) (PTCC) to clear the cases on the basis of revised formula for installation of GD tubes. This is as per the discussions held at the high level meeting convened by Secretary (P) on 23rd September 1982, wherein it was decided that the revised formula of clearance with 20 GD tubes would be used for the present. The 20 GD tubes formula was accepted by Department of Telecom vide their letter No. 130-21/83-TPL (TX) dated 6th August 1983 and is illustrated in Appendix IX to Chapter I.

    1. PTCC Route Approval

      1. Instances where the then Mysore Electricity Department erected and energized their HT lines without the approval of the PTCC were brought to the notice of the Committee in 1955, which requested the Government of India to draw the attention of the Mysore Government to the position which is in contravention of Section 32 of the Indian Electricity Act, 1910. Similar action was taken in the case of the Bareily – Haldwani 66 KV line put up by the Sharda Hydel authorities in Uttar Pradesh.

      1. The meeting held in January 1959 suggested the preparation of a set of directives and graphs which would enable Telecom field officers to tackle cases of parallelism involving power lines upto 11 KV.

      1. In the meeting in February 1961, the Chairman clarified that the approval of the PTCC was only in regard to the route of the line and that any conditions laid down by the PTCC had to be complied with before permitting the energization of the line by the local telecom authorities. It was also pointed out that as per Indian Electricity (I.E.) Rules, it was incumbent on the Power authorities to give an advance notice prior to energization of the line which should enable the local telecom authorities to take action to ensure that the conditions, if any, stipulated by the PTCC have been complied with before energizing the line.

      1. In the meeting held on 21st October 1972, the representatives of the Telecom Department pointed out that it would not be possible to give approval on the basis of data furnished by Power authorities in regard to telecom lines with application for power lines. Certain data might be overlooked when information thereon is furnished by State Electricity Boards.

      1. The meeting held on 25th January 1974 decided that the Joint Secretary (Power) and Joint Secretary (Telecom) of Central PTCC should co-ordinate and prepare a detailed procedure for reference of cases to the PTCC taking into account the requirements of the Railways. A copy of the procedure was prepared and circulated to all concerned in July 1974. In the meeting held on 3rd September 1974, the attention of State Electricity Boards and P&T was drawn to the stipulation that the questionnaire and other data relating to power parallelism should be furnished to the PTCC at the survey stage of the power or telecom lines so as to provide adequate time for obtaining the required data and processing the cases for approval. Procedure for clearance of power and telecom cases is detailed in Chapter III of this manual.

      1. The meeting held on 21st October 1972 appointed a sub-committee to recommend the stage at which cases for approval of the route of transmission lines should be referred to the PTCC, the time-limit within which they should be processed and the time that must elapse before energization of the route after approval is given. Another sub-committee further reviewed the recommendations of the sub-committee. The final recommendations were accepted for implementation in the meeting held on 24th February 1982. ‘Time Limits’ for various steps involved in PTCC clearance, circulated vide CGM, T&D Circle, Jabalpur letter No. TD/LP-2091 dated 23rd April 1982 are reproduced in Appendix X to Chapter I.

      1. The meeting held on 1st July 1977 ratified the proforma for PTCC route approval. In the meeting held on 8th May 1981, it was decided to add an additional clause in the PTCC route approval certificate, to the effect that the energization of Extra High Tension (EHT) power lines would not be held up for want to installation of GD tubes on telecom lines when the induced voltage are in the range of 430 to 650V. This is because GD tubes in this range are recommended as additional protection at their own cost by DOT, although the accepted PTCC safe limit is 650V for EHT power lines i.e. 66 KV and above. Proforma of Route Approval is given in Appendix XI to Chapter I.

      1. In the meeting held on 30th October 1979, it was decided that for route approval cases of power lines involving double circuits the induced voltage calculations should be made considering the double circuit alignment even when only one circuit is initially erected.

      1. In the meeting held on 24th February 1979, it was decided that while referring the tap lines, Power authorities should indicate the details of the PTCC approval for the main line. Wherever route approval particulars are not available full details of main line should be submitted along with the proposal for approval of tap lines.

In the meeting held on 29th September 1988, it was agreed that if the proposal for main line is also received along with the tap lines, the clearance of tap lines would be expeditiously done after examination without waiting for the clearance of main line as far as possible. However, the clearance of the main line will be decided subsequently, if it is possible to delink the main line case with that of tap line and whatever protections would be needed on the telecom line would be provided on the existing principles of later entrant etc.

In the meeting held on 11th November 1991, the State Electricity Board representatives expressed their difficulties to furnish the details of the long existing main lines while seeking clearance of Loop-In-Loop-Out (LILO) / Tap lines. Relaxation in the matter was considered and it was said that only those cases where induction effect appears dangerous on preliminary examination, the complete main line details may be called for and the case examined in detail.

      1. It was decided in the meeting held on 29th July 1983 that the route approval for power cables would continue to be issued on lines similar to those for overhead power lines taking into account the Screening Factors due to power and telecom cables in computing the induced voltages.

      1. In the meeting held on 16th February 1995, it was reiterated that in principle all the proposals for PTCC clearance should be submitted in advance at the survey stage in order to give sufficient time for processing the cases for approval.
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