State to counter power overdrawal by neighbours

KOLKATA: Because of overdrawal of power the Bihar state electricity board and Gridco, the transmission utility of Orissa, the West Bengal government may ask the CESC and the WBSEB to keep their underfrequency relays inoperative.
The underfrequency relays had been installed by some of the power distribution agencies in West Bengal to help cutting off supplies in a part of the power supply grid and save the entire grid from collapsing when there is overdrawal of power at some point in the grid, leading to a fall in the frequency of supply.
In the late 1980s and early 1990s, such grid collapses had become almost a regular ocurrence, leading to widespread disruptions in power supply. During this period, the CESC had taken the pioneering step in the eastern region in installing underfreqency relays.
Now that the entire power supply grid in the eastern region is integrated, the underfrequency relays have become a handicap for consumers in Kolkata and the districts.
The problem is mainly created by Bihar SEB and Gridco. Despite restrictions imposed on them by the National Thermal Power Corporation for non-payment of dues in recent months, these two utilities drew excessively from the grid, leading to almost a total grid collapse.
The problem is more for West Bengal, as it is the only state in the region which has under frequency relays. “While other boards get away with over-drawing of power, consumers in West Bengal suffers as large parts go without power due to these relays,� a senior state power department official said. Because of the relays, supply is automatically cut off in CESC and WBSEB areas.
In this situation, the state government has informed the EREB, which oversees the eastern regional grid, that it “might be constrained to instruct CESC and WBSEB to bypass UFRs, unless all other constituents of the region participate in the UFR operation,� the EREB agenda paper stated.
The issue would be discussed at the next meeting of the board, slated to be held on August 20. Grid indiscipline has been clearly indicated in the recent readings of the Eastern Regional Load Dispatch Centre.
Over the years, ERLDC figures show that the percentage of time that the frequency has dropped below the optimum level of 48.5 Hertz has been increasing. While this was only .69 per cent in 1998-99, it went up to 2.03 per cent in 2000-01, and last year, it reached an all-time high of 5.6 per cent.
A solution that is being talked about in the power circles is the introduction of availability-based tariff (ABT). ABT involves each power utility declaring every hour how much power it plans to generate or draw from the grid. In case any one does not follow this, monetary penalties will be issued.
“Introduction of ABT needs to be done as soon as possible to ensure grid discipline,� WBSEB chairman GD Gautama said.