CPDCL might be left with lesser power at its disposal during times of crisis

Discom can't overdraw to tip the grid frequency below 49.5 Hz

Increase in penalties for overdrafts from grid to “curb States to heavily overdraw”

HYDERABAD: With the Central Electricity Regulatory Commission (CERC) notifying its new Indian Electricity Grid Code, the Central Power Distribution Company (CPDCL) might be left with lesser power at its disposal during times of crisis, which could result in unscheduled load reliefs within the Discom's purview.

Operational frequency

According to the changed grid code announced last week, the operational frequency of the grid has been tightened from the earlier range of 50.3 Hz-49.2 Hz to the present 50.2 Hz-49.5 Hz.

This means that the Discom can't overdraw to tip the grid frequency below 49.5 Hz, and if it does, will have to pay huge penalties, extending upto Rs.17 per unit.

At the same time the commission has dis-incentivised over-production by generation stations by lowering the rates when the frequencies exceed 50.2Hz.

Better performance

This is aimed at ensuring better performance of generating stations on one end, and user appliances such as railway traction motors and agricultural pump sets on the other, said a notification from the CERC.

“Frequencies over and above 50 Hz will harm the power generation equipment, while those below 49.5 Hz will damage the motors of the user appliances. Frequency below 49.5 Hz is indicative of low quality power,” said an official from CPDCL.

The Commission also decided to increase penalties for overdrafts from the grid so as to “curb the tendency of some States to heavily overdraw and deprive other States of their legitimately purchased electricity.”


Towards this end, it has proposed amendments to the Unscheduled Interchange regulations. The Unscheduled Interchange(UI) rate refers to the price per unit of electricity drawn in excess of the Central share allotted to the State.

Coming into effect from May 3, instances of overdraft from the regional grid (in CPDCL's case, Southern Grid) below 49.5 Hz will attract penalties of 40 per cent over normal UI rate of Rs.8.73 per unit.

Erring Discoms

It will be 100 per cent if the grid frequency is below 49.2 Hz, forcing the erring Discoms to shell out more than Rs.17 for every unit overdrawn.

Load relief

“It may not have immediate effect on the Central Discom considering the recent respite from heat, and the reduced agricultural loads. Nonetheless, with reservoirs going empty, we will have to continue with the load relief schedules for domestic users,” said an official.

However, the situation might not be the same when loads across the Southern States peak along with the summer heat.

High consumption

CPDCL is notorious for its overdrafts from the grid due to its high consumption figures.

It had to pay a penalty of nearly Rs.1.2crore last year in the month of April alone for overdrafts. In order to avoid penalties, the company will have little choice but to impose unscheduled load reliefs.

“It also depends on the amount of power drawn by the other states at a particular point of time,” said the official.