Barring gear of steam turbine

Barring gear (or "turning gear") is the mechanism provided to rotate the turbine generator shaft at a very low speed after unit stoppages. Once the unit is "tripped" (i.e., the steam inlet valve is closed), the turbine coasts down towards standstill. When it stops completely, there is a tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long. This is because the heat inside the turbine casing tends to concentrate in the top half of the casing, making the top half portion of the shaft hotter than the bottom half. The shaft therefore could warp or bend by millionths of inches.
This small shaft deflection, only detectable by eccentricity meters, would be enough to cause damaging vibrations to the entire steam turbine generator unit when it is restarted. The shaft is therefore automatically turned at low speed (about one percent rated speed) by the barring gear until it has cooled sufficiently to permit a complete stop.

Raichur-Solapur line

Raichur-Solapur line's working fine, stable now: Power Grid Power Grid's Raichur-Solapur line has been connected to national grid. RN Nayak, the CMD says there were four trippings in the first week. Two were to increase reliability and were done intentionally, and the other two were because of a few glitches. For the last month there has been no tripping.

With the synchronization of the Southern Grid with the National Grid on January 1, the power starved Southern region is expected to get major relief with the grid becoming fully operational by July this year with a capacity to carry around 5,000 MW of power.

The Power Grid Corporation of India Limited (PGCIL), which is the nodal agency for implementing this project, is at present carrying out experiments to study how the grid could be made stable. At present, the grid has a capacity to carry around 1,500 MW of power and this will go up to 5,000 MW by June or July this year when the grid becomes fully operational.

“We expect the study to complete by June-July and the operations to start in full swing thereafter,” PGCIL CMD R. N. Nayak said.

The Tamilnadu government has entered into agreements with companies in Chhattisgarh, Odisha, Jharkhand and Maharashtra to source 2,158MW of power. Nearly, 1426MW would be made available to the state once the Raichur-Sholapur transmission line is operational in August, the chief minister said.

Sidharthan G.
Electrical Miracles.

PURGING OF BOLIER

To avoid furnace explosion

Before every light up of boiler purging is extremely necessary to avoid furnace explosion due to accumulation of unburnt fuel in furnace.in purging i.d.fan and f.d.fan is kept running on at least 30% load so that all unburnt fuel accumulated in furnace may be escaped from chimney.

Sidharthan G

Electrical Miracles.