(1) Power line carrier communication (PLCC) shall be used in the grid network between two consecutive substations and power line carrier communication shall provide speech, data and tele-protection requirements of the power system.
(2) Power line carrier communication shall be duplex, independent transmission (Tx) and receiving (Rx) channels, operating in the carrier frequency spectrum 40 to 500 kHz.
(3) Power line carrier communication terminal shall be operated in either analogue power line carrier communication or digital power line carrier communication (DPLC) or mixed mode.
(4) Power line carrier communication shall be suitable for use with the outdoor equipment viz. line traps, capacitive voltage transformer (CVT), coupling device and high frequency (HF) cable.
(5) Input circuit of the power line carrier communication terminal shall be provided with protective device to eliminate any surge transfer.
24 THE GAZETTE OF INDIA : EXTRAORDINARY [PART III SEC. 4]
(6) Companders and expanders shall be provided to improve voice transmission characteristics for the system.
(7) Fail safe devices shall be provided to avoid malfunction in one unit or damage of any subassembly.
(8) Power line carrier communication set shall be designed to give guaranteed performance from 0 deg.
C to 50 deg. C and the thermal capability of the equipment shall be so designed to be operational up to 55 deg. C for 24 hours continuously.
(9) Coupling device (line matching unit and protective devices) shall be interposed between the capacitive voltage transformer and the connection line (co-axial cable) to the power line carrier communication terminals and shall conform to the carrier frequency operating characteristics between phase to earth coupling units as specified in following Table, namely: - TABLE Serial number Characteristics Units Values
(1) (2) (3) (4)
1. Nominal impedance (equipment side) 150 (for balanced secondary circuit) 75 (for unbalanced secondary circuit)
2. Maximum composite loss decibel (dB) 2
3. Return Loss decibel (dB) Equal to or greater than 12 decibel (dB)
4. Transmission band Kilo Hertz (kHz) 40 to 500
(10) The coupling device shall be suitable for outdoor mounting and shall be fitted on the steel structure and the temperature of metallic equipment mounted outdoor is expected to rise up to 65 deg. C with ambient temperature of 50 deg. C.
(11) High frequency cable shall be provided to connect coupling unit installed in the sub-station to the power line carrier communication terminals installed indoors, and values of attenuation per km of the cable shall be as per the following Table, namely: - TABLE Frequency (kilohertz) Attenuation (decibel/Kilometer) (dB/km) 10 0.8 60 1.4 300 3.3 500 4.7
(12) The nominal bandwidth for transmitting or receiving shall be programmable from 4 kilohertz (kHz) to 8 kilohertz (kHz) in steps of 4 kilohertz (kHz). Power Line Carrier Communication terminal at bandwidth of 4 kilohertz (kHz) shall be suitable for following configuration, namely: -
(a) speech + 4 x 1200 Baud Data (minimum);
(b) data rates shall be selectable in steps, compliant with commonly used standardised data rates such as 200, 300, 600 and 1200 Bauds; and for digital power line carrier communication 1200, 2400, 4800 and 9600 bauds;
(c) gross speed and transmission bandwidth shall be programmable for up to 28.800 kilo bit/s in 4 kilohertz (kHz) spectral bandwidth, up to 72 kilo bit/s in 8 kilohertz (kHz) bandwidth;
(d) return loss in the transmitter band shall be >10 decibel (dB);
(e) tapping loss shall be <1.5 decibel (dB) (as per International Electro-Technical Commission (IEC):60495);
(f) automatic gain control (AGC) range of the receiver shall be 40 decibel (dB) (minimum).
(13) Regarding data multiplexing-
(a) power line carrier communication terminal shall be provided with an internal multiplexer for the time division multiplexing of up to eight serial data channels which can be allocated individually to the internal modems.
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(b) data ports shall be compliant with V.24/V.28, RS232 and/ or V.11/ X.21/ X.24 as per functional requirement.
(c) ethernet port shall be provided for equipment configuration via Local Area Network (LAN), or for general IP forwarding and shall have facility to operate at 9600 bits/s at good signal-to-noise ratio (SNR) of 35 decibel (dB) and above within the nominal band width of 4 kHz and this functionality shall be possible for signal-to-noise ratio (SNR) of 25 decibel (dB) for band width of 8 kilohertz (kHz).
(14) Power line carrier communication equipment comprising of not limited to the following shall be provided -
(a) coupling devices (Line matching unit and protective devices);
(b) coupling filters;
(c) high frequency cable;
(d) power line carrier terminals;
(e) tele protection equipment;
(f) private automatic exchange;
(g) 48V direct current (DC) power supply equipment; and
(h) wave trap.
(15) The relevant standards and code of practice of power line carrier communication as specified in the Bureau of Indian Standards (BIS), the International Electro-Technical Commission (IEC), the European Standards (EN) and the International Special Committee on Radio Interference (CISPER) shall be followed.
CHAPTER VI CELLULAR COMMUNICATION