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CHAPTER II ROLE OF PTCC AND PTCC CLEARANCES 2.1 Power and Telecommunication Co-ordination Committee (PTCC) is a central standing committee for co-ordination of Power and Telecommunication system. The committee was formed by the...

CHAPTER II ROLE OF PTCC AND PTCC CLEARANCES 2.1 Power and Telecommunication Co-ordination Committee (PTCC) is a central standing committee for co-ordination of Power and Telecommunication system. The committee was formed by the Government of India in the year 1949.The objective of the PTCC is to ensure the safety of telecommunication equipment and precious human lives of personnel working in the concerned organizations as also those working in the close vicinity of power transmission line. The role of the committee is to deal with route approval for all new power lines. The PTCC have issued guidelines and manuals from time to time for preparation of proposals for clearance. The norms are reviewed by PTCC to affect changes in line with the technological advancements and bringing safety standards. The clearance of this committee is required before energization of new power lines of 11KV and above, which is given after obtaining clearances from the Railway/Telecom having lines in the area. 2.2 Various committees connected with Power and Telecommunication Co- ordination: i. Central Standing Committee: This consists of two representatives from DOT and two from Central Electricity Authority (CEA).This was set up by the high level committee to look into estimates, which have resulted in delay in settling re-engineering cases. ii. High Level Committee: This is a committee at the level of secretaries or Chairman/Members of the Board from Power and Telecommunication sectors. The committee is assisted by officers from the two sides. Cases where no consensus could be arrived at the level of the central PTCC are referred to this committee. Officers from the Railways are invited when there are issues involving them. iii. Central PTCC: This consists of members from the CEA, DOT, Railways and the Army. The composition of the committee is given in Annexure ‘A’. The basic functions of this committee are: a) To consider all matters relating to adverse effect of power lines on telecom lines. b) To consider specific cases of route approval of power lines exceeding 33 KV and telecom lines. c) To consider and adopt new protective measures to minimize the cost of protection. iv. State Level PTCC: The present membership of the State Level PTCC consists of officers of Junior Administrative Grade from the concerned SEB, Telecom Circle, Railways and Defence. The composition of the committee is given in Annexure ‘B. The main function of this committee are: a) To review the progress of route approval cases of 11 KV lines dealt with by Telecom District Engineers. Indian Railways Telecom Manual - 2021 Page 8  b) To consider route approval cases up to service voltages of 33 KV. c) To consider re-engineering schemes for cases where induction exceeds the protection limit for GD tubes. d) To co-ordinate and watch the progress of installation of protective measures and re-engineering works and issue of energization certificates on completion of protective works. e) To consider violation of PTCC regulations and take suitable corrective measures. f) To discuss cases of power lines of 66KV and above held up for PTCC clearance Various Level of PTCC meeting: S. No. PTCC meeting Frequency/Periodicity 1 Central level Once in six months 2 State level Once in three months 3 SSA/Telecom District Once in three months 4 Divisional Level Once in two months 5 Sub divisional level Once in a month 2.3 (i). Central PTCC deals with cases of energization of power lines of 220KV and above. (ii). Cases of energization of power lines up to 132KV DC are processed at the state level. However, for cases of 33KV DC and above up to 132 KV DC, final PTCC clearance is to be given by DET(PTCC). For cases of above 11KV up to 33KV S/C clearance is given by State Level PTCC. For power lines of 11KV, clearance is given by DET of the Telecom Department. 2.4 Copies of route map drawn to a scale of 1 cm=0.5 km of the proposed electrical lines are to be submitted to the GM(S&T) of the concerned Railways in 4 copies. The Route Map should depict all topographical details including Railway lines, Railway stations, Rivers, Canals and important roads and other land marks like towns, villages with names etc.at a radius of 8 Km around the proposed power line. Topographical maps of the Survey of India are used for this purpose. The distances over which the details are to be marked, are as under: Capacity of Power Line Telecom assets to be marked HT (High Tension power line) 11 KV 3 Kms on either side of proposed power line 22 KV 5 Kms on either side of proposed power line 33 KV SC (Single Circuit) 5 Kms on either side of proposed power line EHT (Extra High Tension power line) 33 KV DC (Double Circuit 8 Kms on either side of proposed power line 66 KV SC and above 8 Kms on either side of proposed power line Indian Railways Telecom Manual - 2021 Page 9 2.5 On receipt of the power line route maps, Railways shall check whether the proposed power line falls within the jurisdiction of the Zonal Railway. If it does not fall within the Zonal Railways jurisdiction, the proposal shall be returned back to the PTCC without any delay and the Railway to which it should be sent shall also be advised. The Railway concerned on receipt the proposal shall mark their telecom lines on the maps and submit one copy to the PTCC. The details in full of all the circuits working on the telecom alignments giving the discontinuity points and route length should be furnished. 2.6 Induced voltage calculations are calculated by the following: Above 11 KV 33KV Double Proposed and up to Circuit (DC) 11 KV Above 132 KV Power Line 33KV Single and up to 132 Circuit(SC) KV Central Electricity Calculation DET Authority, New of I.V done SLPTCC SEB Concerned Delhi by (CEA, New Delhi) Method to calculate Induced Voltage : The induced voltage on a telecommunication line during an earth fault on the power line is given by the expression: V=MxI Where V is induced voltage in Volts, I is Earth Fault Current in Amps and M is Mutual Coupling in Ohms between Power line and telecom line The value of Mutual Coupling (M) depends upon the distance between the power and telecom lines, the length of parallelism, the fundamental frequency of the power supply and the soil resistivity of that area. Indian Railways Telecom Manual - 2021 Page 10  Flow Flowchart for the processing of PTCC Route approval of Power Lines A. Power Lines above 132KV Begin Proposal for PTCC Route Approval forwarded by Power Utility/SEB to Director (PTCC), GM (S&T) of the Concerned Concerned Divisional CEA concerned DET, PTCC Engineer of Telecom Railways circle, BSNL Marking of Railway Compiling of all Marking of Telecom Telecom Details by BSNL Details Details Railway Authority Calculation of Induced Voltage figures & Forwarding to GM (S&T) of the concerned Concerned DET for issue of Railways for issuing NOC PTCC Route Approval If IV Figures NO NO If IV Figures within safe within safe limits? limits? Re-engineering proposed Yes Yes NOC Issued by PTCC Route Approval issued by concerned Railways DET(PTCC) on behalf of Central PTCC End Indian Railways Telecom Manual - 2021 Page 11  B. Power Lines up to 132 KV Begin Proposal for PTCC Route Approval forwarded by Power Utility/SEB to GM (S&T) of the Concerned DET, PTCC Concerned Divisional concerned Railways Engineer of Telecom circle, BSNL Marking of Railway Compiling of all BSNL Marking of Telecom Telecom Details by details Details Railway Authority Power Utility/State Calculation of Induced Voltage figures Electricity Board & Forwarding to GM (S&T) of the concerned Concerned DET for issue of Railways for issuing NOC PTCC Route Approval If IV Figures NO NO If IV Figures within safe within safe limits? limits? Re-engineering proposed Yes Yes NOC Issued by PTCC Route Approval issued by concerned Railways DET(PTCC) on behalf of Central PTCC End Indian Railways Telecom Manual - 2021 Page 12 2.7 Safe limit for induction due to Low Frequency Induction due to short circuit fault is 430V and is generally the ruling factor. In specific cases, longitudinal induced voltages under normal conditions are to be examined. In case, where the induced voltages due to short circuit fault on the telecom circuits, exceeds prescribed safe limit of 430V, it is necessary to consider various protection measures so that the equipment installed and the personnel working on these circuits are not subjected to the influence of hazardous potentials. One of the measures commonly adopted for protection is the use of three electrode Gas Discharge (GD) tubes. Two electrodes of the tube are connected to the wires of a telephone pair and the third electrode to the earth, through the earth cap. Under normal conditions, the telecom line is kept insulated. The gap breaks-down and the telecom line is virtually earthed, when induced voltage excess the pre-determined value (250V). Through the discharge path, the earth connection to the tube should be of very low resistance so that the voltage across the tube is restricted to safer values. Numbers of GD Tubes are required for protection: Nos of GD tubes = Induced Voltage/Constant, Value of constant is 300. If value comes in fraction then it is rounding off to next integer value. If Nos of GD tubes are 3 then two GD tubes should be installed at the ends of telecom lines in the paralleling section and one in the middle of these two. In case the number of GD tubes worked out are more than three, two of these should be fitted at each end of the paralleling section of the telecom lines and the rest of the GD tubes be fitted in between space at equal intervals. GD tubes worked out by the above method should be fitted on all the telecom wires in the paralleling section. 2.8 Protective measures against induced voltages in excess of the safe limits on different types of block instruments in use in Indian Railways is given in Appendix XVII to Chapter I of PTCC manual – edition 2010. The limits for the block instruments presently in use on IR are given below: (i) SINGLE LINE BALL TOKEN/ TABLET TOKEN BLOCK INSTRUMENT (a) For induced voltage not exceeding 430 V no special precaution is necessary. (b) For induced voltages exceeding 430 V metallic return and appropriate Gas Discharge tubes are to be provided. (ii) Double Line Block Instrument As in Sl. No. (i). (iii) Kyosan Tokenless Push Button 650 V AC with modification similar to Podanur’s Tokenless Single line block instrument as mentioned below in Item no (ix) Indian Railways Telecom Manual - 2021 Page 13 (iv) Diado Single Line Tokenless Block Instruments Without modification this instrument can safely stand induction up to 74V 50 cycles AC induced voltages. For induced voltages up to 650V AC the following modification is to be made: A-3 position polarized relay of the type used in Neale’s token or SGE double line block instrument is to be interposed in the line circuit and the existing line relay (NR Relay) fed from local battery through the contacts of polarized relay. Also the line condensers C1 & C2 each of the microfarad capacity with a voltage rating of 160V are to be replaced by condensers of equal capacitance but with a voltage rating of 1000V Standard gas dischargers will also have to be provided for the lines. (v) Push Button Type Single Line Tokenless Block Instrument This instrument is only suitable for use in non-AC electrified sections. This instrument is safe for use in block circuits subjected to maximum induction 650V r.m.s. 50 cycles AC from neighboring power line provided the existing DC blocking condenser in the telephone circuits is replaced by a one rated for 1000V DC for non AC section only (non AC electrified). (vi) Sectional Axle Counter for BPAC/IBS/ABS Please refer to OEM manual for voltage limit for safe working. (vii) UFSBI Please refer to OEM manual for voltage limit for safe working. (viii) Electronics Interlocking Please refer to OEM manual for voltage limit for safe working. 2.9 Maximum acceptable limit of induced voltage due to power parallelism is up to 2000V on railway block and communication circuits subject to the specific limitations mentioned above. The cases of induced voltages above these limits should be treated as re- engineering cases and each such case should be treated separately in consultation with the Railway Board. 2.10 Railway control/block and all other Circuits are now normally working on OFC/Quad however Railway control and other overhead circuits to be invariably provided with GD tubes on par with the protective arrangements required for protection of block circuits. 2.11 Interference to signaling circuits shall be checked up with reference to the A.C. immunity of the signaling equipment viz., track circuit relays, line relays, Indian Railways Telecom Manual - 2021 Page 14  point machines etc. Interference voltages to signaling circuits are not provided by PTCC and will have to be done by the Railways in specific cases where interference is suspected. 2.12. After calculation of induced voltages, divisions shall be advised of the protective measures to be taken and final clearances for energization of power lines shall be given only after provision of protective measures is completed wherever necessary. 2.13 Divisions shall ensure that protective measures are maintained properly. During inspections, the availability of the protective measures at the stations shall be checked. 2.14. The expenditure for provision of the protective measures shall be deposited by the agency which carries out erection of the new power lines. 2.15. Method for carrying out low frequency induction test if required, and code of practice for protection from earth potential rise (EPR) are described in the PTCC manual. It should be ensured that the EPR at locations of telephone exchanges, cable joints, terminals, pillars, cabinets etc., is within safe limits. The EPR counters which define hazard zone for telephone plants are given below: S.No. Type of Telecom Plant Type of Power System High Reliability Other Lines Lines 1. Terminal, apparatus, joints, cabinets, Pillars, 650 V 430 V Manholes, Pins, Poles. 2. Telephone Exchanges 430 V 430 V 3. Cables: a) Metal Sheathed 650 V 430 V b) Plastic insulated and plastic sheathed. 7 KV 7 KV 2.16. PTCC Monitoring cell headed by CCE/Dy.CSTE(Tele)/any nominated official by PCSTE of the railway shall monitor the timely disposal of pending and new cases. The cell shall maintain the concerned data on PC with the help of nominated official/supervisor and shall share all relevant information, calculation sheets with divisions. Time limits for obtaining PTCC Route Approval: (i) For Approval of 11 KV Lines – Approval by the respective DEs (Telecom) (a) 8 weeks if the power line proposal pertains to single case. (b) 12 weeks if the cases are referred in-group. Indian Railways Telecom Manual - 2021 Page 15 (ii) For 22 KV/33 KV Power Lines – Approval by the State Level (a) Furnishing the telecom details by BSNL/ 10 weeks Railway/Army etc. (b) Examining cases and computing the 3 weeks Induced Voltage (IV) calculations and forwarding the same to Railways, if required. (c) Forwarding recommendations by Railways 4 weeks (d) Final examination and issue of certificate 3 weeks (iii) For 33 KV D/C and above up to 132 KV Power Lines (Central Cases) (a) Furnishing telecom details by BSNL/ 12 weeks Railway/Army (b) Scrutinizing the details, preparing copies 2 weeks & forwarding to concerned Electricity Board by DET PTCC. (c) Furnishing I.V. calculations by Electricity 10 weeks Board and endorsing copies to all concerned (d) Furnishing recommendations by Railway /Army 4 weeks (e) Final examination & Issue of certificate 4 weeks (iv) For Approval of Power Lines above 132 KV (Central Cases) (a) For furnishing telecom details by 12 weeks BSNL/Railway/Army. (b) Scrutinizing the details, preparing 2 weeks additional copies and forwarding to Joint Secretary Power. (c) Furnishing Induced Voltage 10 weeks calculation by Joint Secretary Power & endorsing copies to all concerned. (d) Furnishing recommendations by Railway/ 4 weeks Army. (e) Final examination and issue of certificate 4 weeks For protective works after the PTCC approval (a) For quoting the charges and furnishing Estimate 8 weeks (b) Arrangement for payment 8 weeks (c) Execution of protective works by BSNL 10 weeks (d) Execution of protective works by Railways 10 weeks Notes: 1. In general, the time schedule recommended for the various functions shall not apply to cases where re-engineering is involved. Even for Indian Railways Telecom Manual - 2021 Page 16  such cases the appropriate authorities may quote the reasonable time required for the re-engineering. 2. The period for implementing the protective works has been recommended assuming the essential materials for those works would be available in reasonable time. 3. If the protective works are to be undertaken by the Department or Agencies other than the Unit submitting the proposal, every attempt should be made for speedy completion of the protective works. However, energization shall not take place if the protections are not completed. 4. The time prescribed may be taken as maximum. For watch and monitoring - Cases below 33 KV: - Necessary monitoring and watching would be done by the respective State Level PTCC Committees. - The Standing Sub-committee will examine badly delayed cases of 33 KV D/C and above. - Information pertaining to such cases would be called for in the prescribed form from the various DETs (PTCC) for review by the Sub-committee Indian Railways Telecom Manual - 2021 Page 17  Annexure-‘A’ COMPOSITION OF THE CENTRAL PTCC: Chief Engineer (LD & T), 1. Central Electricity Authority,New Delhi Chairman Chief General Manager, T&D Circle In Alternate 2. Bharat Sanchar Nigam Ltd (BSNL) Years Jabalpur Director (PTCC), 3. Secretary (Power) Central Electricity Authority,New Delhi Deputy General Manger, T&D Circle 4. Secretary (Telecom) BSNL, Jabalpur Director (Telecom), Railway Board 5. Member New Delhi 6. Jt. DDG (ML), Ministry of Communication Member 7. Chairman/ Co-Chairman of SLPTCC Member 8. Director (GP), Ministry of Communication Member 9. Representative of Dept. of Power Member 10. A representative from the Army Headquarters Member 11. DDG(NE), TEC, BSNL, Hyderabad Member 12. DET (PTCC), T&D Circle, BSNL Member Indian Railways Telecom Manual - 2021 Page 18  Annexure-‘B’ COMPOSITION OF THE COMMITTEE AT STATE LEVEL: 1. GM (Telecom) of concerned Telecom Circle, BSNL Chairman In Alternate Chief Engineer (Transmission) of the concerned Years 2. SEBs/ State Power Transmission Corporations DGM (Telecom) who deals with PTCC matters of Secretary (SLPTCC) 3. the Telecom Circle Telecom Sector SE/DGM, who deals with PTCC matters of the Secretary (SLPTCC) 4. State Power Utility. Power Sector EE of Power Utility / SDE (PTCC), T & D Circle 5. Co-ordination Secretary BSNL Other members from Power Sector Zonal SE/ EE in-charge of PTCC Member 6. Representative from any other Central/ State Member Power Trans. Corporation Chief Electrical Inspector or his authorized Member representative from state Other Members from BSNL AGM (Plg) in charge of PTCC, BSNL Member 7. DET (PTCC), BSNL of the concerned region Member Any other representative of BSNL as special Member invitee, as required 8. DSTE of Zonal Railway Member 9. Army representative of the Area Member -x-x-x- Indian Railways Telecom Manual - 2021 Page 19