15.11 PLANT COMMUINICATION SYSTEM
15.11.1 The system shall consists of electronic private automatic branch exchange (EPABX ), public address for the complete power plant including switchyard, coal handling areas, ash handling areas, CW and other off site areas.
Electronic Private Automatic Branch Exchange (EPABX)
Plant communication system shall include a private telephone exchange. The telephone exchange shall be 32 bit microprocessor base Electronic Pvt. Branch exchange (EPABX) for industrial telephone communication system. The exchange shall have facility to connect D.O.T / truck lines
The EPABX shall be of approved technology of department of telecommunication, Government of India. It shall have fully non blocking architectural.
EPABX shall have `1 no. 200 lines, expandable to 256 lines including 8 P&T and digital lines.
15.11.2 The exchange shall be suitable for high speed digital data and voice communication and shall have the facilities to connect data terminals from fax machine and personal computers along with telephone services.
15.11.3 The battery and battery chargers combination shall be such as to ensure continuity of D.C. supply to EPABX system at all times without even momentary interruption of serviced.
15.11.4 The facility to be provided by EPBAX system shall include but not limited to the following:
i. Hold for enquiry
ii. Shuttle on enquiry calls.
iii. Call store and retrieve.
iv. Wait on busy
v. Pick-up
vi. Call transfers.
vii. Conference
viii. Automatic call back.
ix. Call diversion.
x. Music on hold.
xi. Auxiliary equipment assess.
xii. line lock out.
xiii. Howler tone alert.
15.11.5 Operator Console.
The operator console shall have PC base maintenance – cum-operation / Administration facilities along with necessary display (VDU), key board printer etc. and include but not limited to the following features;-
i. Subscriber calling.
ii. Call hold.
iii. Camp on ringing.
Iv,. Camp on busy.
v. Prevention of double cam on.
vi. Serial calls.
vii. Call monitoring.
viii. Busy over right.
ix. Abbreviated dialing.
X, Answering priority
xi. Call sequencing.
xii. Paging access.
xiii. Station busy display.
xiv. Incoming call type display.
xv. Trunk number and type display.
xvi. Waiting call display.
xvii. System alarm display
xviii. Digital clock.
xix. Listen in
xx. Night / off duty service.
xxi. Departmental calls.
xxii. First party release.
xxiii. On line package replacement.
xxiv. Direct station selection.
xxv. Direct inward dialing.
15.11.6 Telephone set.
The telephone sets shall be of the following types :
Desktop push button operated decadic type with tone dialing (ordinary) – Type ‘A’.
Desktop push button operated decadic type with tone dialing and 10 nos. memory storage type “B”
Same as type ‘A’ but wall mounted type instruments type “C”
Flamproof telephone instruments type “D”.
15.11.7 Telephone cables.
Telephone cable shall be 0.5 mm dia annealed electrolitic copper conductor both inner and outer sheet PVC insulated, color coaded twisted pair, laid up , taped galvanized round / flat wire armoured conforming to IS-1554.
Cable sizes shall be standardized in terms of the no. of pairs , which shall be 100 pairs, 50 pairs, 20 pairs, 10 pairs, and 5 pairs.
15.11.8 Junction boxes.
The telephone junction boxes shall be of MS steel / fibre having IP-52 degree of protection for outdoor duty and IP-42 for indoor duty. It will be complete with jumper , terminal block, earthing , studs suitable for terminating OR looping telephone cables.
15.11.9 Public Address (PA) System.
Distributed PA system shall be supplied for the main plant, offsite areas and CHP areas. PA system shall be micro-processor based and user programmable. The system shall comprise of four (4) sub-groups, namely Sub-group-1 for Unit No.1. Sub- group-2 for Unit No.2 , Sub-group-3 for Common Areas like Switchyard and Offsets, Sub-group-4 for CHP area. List of distribution of PA system Field Call Station (CCS) is given in Annexure-B.
15.11.10 The system shall have four (4) channel party and page system with facility of inter connection among the sub-groups through Master Call Station (MCS). The system shall be operative without interruption even on station AC supply failure. Incoming supply shall be fed from main plant UPS.
15.11.11 The PA system for coal handling plant area, shall be suitable for heavily dusty atmosphere. This system shall avoid use of handsets, as these are susceptible to pilferage in such areas.
15.11.12 System details
a) PA system shall have four (4) channels party / channel page system.
Following communication modes are possible:
i. Between Field Call Station (FCS) in the same subgroup without the help of Master Call Station (MCS).
ii. Between Master Control Station and any Field Call Station (FCS),
iii. Between an EPABX subscriber with the Field Call Station (FCS) through EPABX interface.
Individual system shall be expandable with maximum number of sets per system limited to 100 nos.
b) each group shall consist of the following main equipment.
i. Indoor/Outdoor, column/wall/desk-mounted Field Call Stations (FCS) with built –in-amplifiers of adequate output capacity. Extension amplifiers shall be provided for desktop mounted handset station wherever needed.
ii. Horn type loudspeakers.
iii. Indoor cone type loudspeakers.
vi. Main junction boxes & distribution boards and junction boxes for handset station and for loudspeakers etc.
v. Weatherproof canopy / box for outdoor handset stations.
vi. Acoustic hoods.
vii. Cables.
viii. Conduits, if required.
ix. Central Control Exchange.
x. One desk mounted type Master Call Station (MCS).
c) Desk mounted HS for unit control rooms shall have snap action self return micro switches for different functions such as PAGE, LOUDSPEAKER MUTE and SIREN, LED indicating lights, a built-in-loud speaker and dynamic, noise canceling microphone.
d). Desk mounted Master Control Station (MCS) shall have a multifunction key-board, a backlit display, a press to page switch, a gooseneck microphone with dynamic noise-canceling and a built in speaker. The communication from MCS to any field station is a hands-free voice switch duplex communication without requiring number dialing.
e) Outdoor/Indoor FCS shall be provided at various locations of the plant and auxiliary buildings. In some areas for noisy areas such as turbine hall, mills etc. HS’s shall be provided with acoustic hoods to cut down the ambient noise for proper communication.
f) Where cable trays are not available cables shall be laid directly along the wall.
g) The outdoor LS shall be of weather proof die cast aluminum construction.
h) All outdoor HSs shall be provided in the weatherproof boxes with canopies.
i) For areas where false ceiling will be provided, cone type speakers shall be suitable for false ceiling mounting.
j) All outdoor type handsets and speakers shall be provided with dust and weather proof, pilfer proof enclosure with locking facilities.
15.11.13 Walky Talky System
Walky Talky System shall be a two-way radio communication system with an effective reach of 5 km. Radius. The system shall comprise of repeater, a VHF antenna and 20 Nos. talk-back transreceivers.
Repeaters are special relay station which re-transmit one users transmission to another. If comprises of receive, transmitter, interface controller, power supply and duplexer.
As soon as repeater receives a valid signal its transmitter turns on. The receives audio is fed into the transmitter, which then retransmits the same. Retransmission usually happens on a different frequency so that it does not load the receiver and create a loop. The duplexer provides additional isolation of 0-1000 dB.
