Mumbai Blackout: How Tata Power islanding system works in restoring power distribution?
Mumbai, Oct 12: A major power outage was reported in Mumbai on Monday with residents taking to Twitter to report blackout in south, central and north regions.
Power cut across the Mumbai Metropolitan Region due to grid failure," the Brihanmumbai Electric Supply and Transport agency said on Twitter. Stock exchanges BSE and National Stock Exchange of India continued to function normally. It could take a few hours as electricity is restored.
In the wake of breakdowns in the national electricity grid systems recently, the way Mumbai has been managing to 'island' itself in this regard has interested many. It is why the city has, in the past, enjoyed uninterrupted power supply.
Tata Power had designed the islanding scheme in 1981. It has been upgraded, with active participation of Reliance Infrastructure (R-Infra) and the BrihanMumbai Electric Supply & Transport (BEST), in line with the network development and generation additions, learning from each occurrence.
It has ensured continuity of power supply to all essential services in the event of a breakdown in the Western Regional Power Grid, and assured an uninterrupted and reliable supply of power to the city of Mumbai for almost 3-4 decades.
Thermal and hydro generating plants have been provided with islanding schemes to facilitate quick restoration in case of a blackout.
Since the technique was first implemented, there have been 37 major grid disturbances in Mumbai, and the city has survived 27 of those successfully. The system has achieved 100 percent success rate since 1997, having operated successfully on all 16 occasions. The scheme has been provided on all tie-points to simultaneously island and operate the Mumbai system in isolation.
At the core of reliable power supply to the city is the unique 'Islanding System' pioneered by Tata Power, due to which the city of Mumbai has the advantage of assured uninterrupted reliable supply of power.
In case of a grid failure, the Islanding System ensures uninterrupted power supply within the city limits. In case of a breakdown in the Western Regional Power Grid, Tata Power's system is automatically isolated from the rest of the grid. It ensures that our generating units continue to function. All essential services are assured continuity of power supply.
What is Islanding?
Islanding is the condition in which a distributed generator (DG) continues to power a location even though electrical grid power is no longer present. Islanding can be dangerous to utility workers, who may not realize that a circuit is still powered, and it may prevent automatic re-connection of devices. A
Additionally, without strict frequency control the balance between load and generation in the islanded circuit is going to be violated, leading to abnormal frequencies and voltages. For those reasons, distributed generators must detect islanding and immediately disconnect from the circuit; this is referred to as anti-islanding.
A common example of islanding is a distribution feeder that has solar panels attached to it. In the case of a power outage, the solar panels will continue to deliver power as long as irradiance is sufficient. In this case, the circuit detached by the outage becomes an "island". For this reason, solar inverters that are designed to supply power to the grid are generally required to have some sort of automatic anti-islanding circuitry.