National Grid Corp. of the Philippines (NGCP) said it plans to build overhead transmission lines (OHTLs) that can withstand winds of up to 300 kilometers per hour.
The plan is a part of its heightened grid resiliency program under the proposed Transmission Development Plan Report for 2024 to 2050 to improve the ability of the power system to withstand the adverse effects of environmental conditions, natural or man- made power interruptions and other disturbances.
“A high degree of power system reliability is equivalent to the high availability of the electricity supply service, while excellent system security gives robustness to the power system to withstand unexpected events that have severe impact and consequences,” NGCP said in a statement.
“It will take a diversified approach to do this. This entails making investments in upgraded infrastructure to withstand severe weather, putting in place cutting-edge monitoring and control systems to quickly identify and address disruptions, and adding redundancy and backup measures to lessen the effects of malfunctioning equipment or cyberattacks,” it said.
NGCP said it understands the need to strengthen the overhead transmission line support structures considering the increasing number of super typhoons that have devastated different parts of the country in the last 10 years.
The transmission operator said the maximum wind speed design (WSD) of its structures is currently based on three wind zones: Zone 1 (270 kilometers per hour), Zone 2 (240 kph) and Zone 3 (160 kph).
NGCP said it intends to enhance the maximum velocity design of support structures to strengthen the infrastructure against the escalating consequences of extreme weather occurrences.
NGCP said that by raising the WSD thresholds, it aims to strengthen the resilience of OHTLs, thereby mitigating the risk of structural damage and minimizing disruptions to power transmission during severe weather conditions. The company plans to construct OHTLs in Luzon that can resist gusts of up to 300 kph.
NGCP said this 300 kph wind speed design is already being adopted in the Tower Structure Upgrading of Bicol Transmission Facilities and Tower Resiliency of Bicol Transmission Facilities Projects.
NGCP said existing transmission towers—which were initially intended to resist wind gusts of 270 kph for three seconds—are being upgraded or retrofitted.
Other measure includes creating a transmission backbone loop to boost redundancy and facilitate efficient power transfer across several sites.
It also includes selecting sites for substation locations and transmission line routes by using government-provided hazard maps, avoiding areas prone to flood, steep slopes susceptible to soil erosions, and maintaining a safe distance from fishponds, rivers, lakes, swamps and seashores.
