ANNUAL REPORT 2011-12 - State Load Despatch Centre (SLDC)

Annual Report 2011-12
From The Chief Engineer’s Desk
It gives me immense pleasure to present the Annual Report of SLDC, Gujarat for the financial
year 2011-12.
SLDC is mainly carrying out two types of operational activities; one is grid operation to ensure
safe, reliable and economic despatch of electricity in the State of Gujarat and the other is
commercial operation for providing Short Term Open Access, accounting quantum of
scheduled energy, unscheduled energy exchange and reactive energy exchange.
Grid Operation
The generation capacity addition of 18.65% (2845 MW) is achieved compared to 12% addition
during previous year 2010-11. The addition comprises of 1170 MW from Renewable sources,
1000 MW from Private Sector and 675 MW from Central Sector. 36 Nos. of EHV transmission
elements were added in Gujarat system during the year 2011-12. A rise of 10.37% in total
energy catered and a rise of 7.15 % in Maximum demand catered are worth mentioning. The
energy received from renewable sources is 4175 MUs (5.3% of total energy) while it was 2820
MUs (3.96% of total energy) in the previous year and the rise of 48% in contribution from
renewable sources is quite remarkable. These figures indicate that complexity of grid is
increasing enormously. There are lot of uncertainties prevailing in the grid such as demand
variation, wide variation in generation from renewable sources etc. During the year, SLDC has
made numerous efforts to ensure safe, secure, economic and reliable grid operation. In the
beginning of July-2011, multiple line tripping in Saurashtra area owing to bad weather and in
Dec-11, the whole UTPS generation loss due to inadvertent switching operation in switchyard
caused major grid disturbances in Gujarat system. SLDC’s efforts in handling these situations
were indeed noteworthy for quick restoration of the system in both the cases. SLDC is
managing such complexities by using advanced Power System Tools, effective planning for
outages of transmission elements and generating units, ensuring real time data for entire grid
observation etc. Variation of 800-1000 MW generation in a day from renewable sources is
quite common. Such variation in the system is persistent and is handled by continuously
analysing weather related information, generation regulation, optimizing the operation of
lines, ICTs and shunt elements like capacitors and reactors.
Commercial Operation
By mandate, SLDC is the nodal agency for STOA in the State. SLDC has to carry out energy
accounting for computation of capacity charges, scheduling charges and transmission losses.
Also, SLDC has to maintain and manage UI Account, Reactive Energy Account and Congestion
Charges Account and RTDA Account. It is our pride that Gujarat State has implemented Intra-
State ABT Mechanism complete in all respects since April 2010 for better grid discipline and
accounting. With the capacity addition taking place at a faster pace, the substantial increase
in interconnections between different subsystems and the inevitable need to provide efficient
and effective STOA platform, the data processing and publishing work at SLDC has
State Load Despatch Centre
Gujarat Energy Transmission Corporation Limited
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