Bohol reconnection to grid by mid-February

NGCP Bohol special tower

Bohol residents may expect the island province to be reconnected to the Visayas Grid by February 15, according to the National Grid Corporation of the Philippines (NGCP).

Speaking at a virtual news briefing on Monday, NGCP Engineering Project Management Department Head Randy Galang said that the grid firm will be employing the emergency restoration system (ERS) as a temporary solution to replace its two special towers that were toppled by Typhoon Odette in December.

The ERS is made up of slings, which would be attached together to form the temporary towers that would carry the cables of the affected transmission line.

However, there are challenges awaiting the restoration team, such as the guy foundations for the ERS.

Yung foundation ng mga guy na ‘yun, [natapat] sa mangrove [that are] marshy and watery areas, so very soft yung [foundation], so we need to bury the anchor plots,” Galang said.

Guys are cables linking the slings to the buried anchors. The guys and anchors provide a support system for the slings.

Galang added that NGCP is coordinating with the Department of Environment and Natural Resources given that mangroves are considered protected areas.

Located on Lapinig Island and mainland Bohol, respectively, Towers 39 and 40 of NGCP’s 138-kilovolt (kV) Tugas-Ubay line lead to the Leyte-Bohol Interconnection. Built in 2000, both towers have a height of 130 meters and are higher than most transmission towers. The said facilities provide 60% of Bohol’s power requirements.

As for the two special towers themselves, NGCP aims to finish rebuilding both structures by April 30.

Using the “build back better” principle, Galang said the new towers would be shorter at 120 meters each, but sturdier, employing a design meant for 500kV lines from the previous 128kV. The replacement structures would also be able to withstand wind speeds of up to 300 kph from the previous 240 kph. They would also have a lighter 27.73 millimeter conductor.

Galang had described he rebuilding of both special towers as an “engineering challenge.”

Power has been partly restored to Bohol even as it is disconnected from the grid, as SPC Power Corporation’s 32-megawatt Power Barge 104 is providing electricity to the province. Distribution-wise, power has been restored to 33% of households served by Bohol Light Co. Inc. — Tagbilaran City’s distribution utility. Power distribution services in the rest of the province have barely moved.