During the days of inception when TNEB established hydro generating stations in hilly areas, communication from and to these generating stations were through magneto phones with hand operated dynamo. These phones used the telephone lines which ran adjacent to the transmission lines. Later, TNEB introduced PLCC system for its own communication requirements. In 1960 PLCC sets and Protection couplers of Brown Boveri Corporation(BBC), Switzerland make (66 Nos.) were put into service covering the following areas:
Aliyar, Sholayar Hydro generating stations.
Basin bridge PH – Korattur SS.
Kundah Hydro generating stations.
Suruliyar Hydro generating station.
Neyveli Thermal station etc.,
During this period Supervisory Control and Data Acquisition (SCADA) system through PLCC was also established in Kundah scheme, Some of salient features of this scheme are:
Telemetering from Kundah PH-1, 3, 4 & 5 to Kundah PH2, the Master Power house.
Control of machine operations of Kundah PH-1, 3, 4 & 5 from Kundah PH2 the Master Power house in remote operation .
In local mode all the power houses can operate independently. In due course, the SCADA has become inoperative. Between 1963 and 1967 Hitachi, Japan make PLCC sets and Protection Couplers (50 Nos) were put into service. Subsequently Hitachi make telemetering equipments were also put into service in TNEB. Later on carrier sets and Protection couplers manufactured in India by ABB, BPL were used.
In the Data communication front, after the establishment of Hitachi make telemetry equipments, cyclic telemetry transmission equipment were installed at Erode and Chennai for transmission of telemetry data from Erode LD Centre to Chennai Main LD centre. First Remote Terminal Units (RTUs) of CMC make were installed in generating stations and major 230 KV Sub stations and ND 110 server system was installed at Chennai in 1988. Now these RTUs have become obsolete and presently ABB,GE Harris, Honeywell RTUs are in service and these have been connected to FEPs at Chennai MLDC, Erode Sub LDC and Madurai Sub LDC. These RTUs and FEPs form part of ULDC SCADA package established under Unified Load Despatch Scheme. Many of the RTUs in this scheme are still connected partly through PLCC and partly through wideband communication channel. Inter LDC data communication and Chennai SLDC to Southern Regional Load Despatch Centre (SRLDC), Bangalore are working through wide band communication established under ULDC scheme
Later VHF communication equipments were installed in Dam sites to acquire reservoir level, Inflow, Discharge etc., These were also provided for fuse of call centres in select towns such as Trichy, Salem, Thirunelveli, Madurai etc.,
For Distribution Control Centre (DCC) SCADA system in Chennai covering more than 100 stations, UHF communication Network are deployed.