CANE POINTS: On Airports and Power Substations

Friday last week (March 21), London’s Heathrow Airport was compelled to shut down its entire operations, sending shivers down the spine of the global aviation industry.

Heathrow is Europe’s busiest airport, catering to more than a thousand plane landings and take offs every day. That fateful Friday, all of Heathrow’s 1,332 scheduled flights were cancelled, affecting more than 220,000 passengers. Hundreds of incoming planes had to divert to other nearby airports, while those which had just taken off had to return to their airport of origin.

Fortunately, after a stoppage of 18 hours, airport operations resumed on Saturday (March 22), though airport authorities admit it would take days before normal operations and regular flight schedules can fully resume. Airlines still need time to untangle the cancelled and delayed flights. But even if they do so, they could no longer bring back the airline passengers’ wasted time and lost opportunities caused by the aborted flights.

UK Prime Minister Keir Starmer was deeply concerned about the incident. “I don’t want to see an airport as important as Heathrow going down in the way it did on Friday, so I’m not comfortable with that for one second,” he said in a BBC interview.

The cause of this havoc at Heathrow Airport? Electrical fire at the power substation which supplies electricity to Heathrow Airport. Fueled by 25,000 liters of substation transformer cooling oil, the fire required the efforts of 10 fire trucks and 70 firefighters to bring it under control. Even with their modern firefighting equipment and large number of responders, it the London Fire Brigade 12 hours to do so.

Negrenses could relate, because they still recall the frustration of travel restrictions during the Covid era. Well-planned vacations, meticulously cultivated business deals and diligently nurtured professional engagements had to be either postponed or cancelled outright because there was simply no means of fast and convenient air travel.

When the Alijis Substation conked out in August 2024, Negrenses almost had a taste of the Heathrow Airport shutdown. Four large barangays in Bacolod City were affected, depriving more than 40,000 households of electric service for several days.

If the airport was still located in Singcang, it would have been also affected by the power interruption. The airport would have been sourcing its power from the Alijis Substation, as it is the nearest to the airport. If there’s no power at the substation, there’s no power at the airport.

The Heathrow Airport incident and the Alijis Substation trouble underscore the importance of a reliable power supply. Considering the role of power substations in the distribution infrastructure and the large area and number of consumers which could be affected if the substation experiences trouble, they have to be maintained in tiptop shape 24/7.

While natural forces, such as the tornado which hit the 69 kV sub-transmission lines near Murcia Substation last March 6, are beyond man’s control, preventive maintenance measures are clearly within man’s prerogatives.

To this end, Negros Power initiated the upgrading of the Panaogao Substation last Saturday (March 22) and the Sum-ag Substation last Sunday (March 23).

Among the upgrades which Negros Power implemented were checking / installing protective devices, such as circuit breakers and disconnect switches, maintenance of current transformers, hotspot correction, installation of new insulators, and replacing bare wires with “tree wires”.

A substation receives high voltage power, thru the power transmission network, from the power generators. This high voltage power is converted into a lower voltage by the substation transformers, which then relays this lower voltage power to the various feeders. In turn, these feeders branch out to deliver power to other distribution transformers which convert the electricity to 220-240 volts for residential use.

If the cooling oil in the substation transformer becomes too viscous, it loses the ability to cool the transformer coils. If it is not addressed, the heat will eventually cause the transformers to explode and burn.

If the cable connections from the substation transformers to the feeders are loose or corroded, the electric sparks from the loose / corroded connections can also cause a fire. If cooling oil is leaking from the transformer, the oil might catch fire from these sparks, thereby setting the entire substation transformer on fire.

Moreover, if leaves and branches of trees and other forms of vegetation get in contact with bare power wires, they might cause fire. Thus, Negros Power replaced these bare wires near vegetation into “tree wires”, which are simply covered conductors / wires to prevent the possibility of fire from contact with vegetation.

All these substation upgrades are part of Negros Power’s five-year rehabilitation and modernization plan. These measures will also be implemented in due time in the other substations serving the Negros Power coverage area to strengthen power reliability in the distribution system and lessen the possibility of prolonged and widespread power interruptions in the future.*