The –Duhat–Hermosa–Duhat–Balintawak Transmission Line (known as the Duhat-Hermosa transmission line) (abbreviated as HB, RHB, 8LI1DUH-HER, and 8LI1QUE-DUH), also known as Hermosa–Marilao–Quezon Transmission Line''', is a 230,000 volt, single-circuit, two-part transmission line in Metro Manila and Central Luzon, Philippines that connects Hermosa and Balintawak substations of National Grid Corporation of the Philippines (NGCP), with line segment termination at Manila Electric Company (Meralco) Duhat substation in Duhat, Bocaue, Bulacan.
History
The Hermosa–Duhat–Balintawak Transmission Line began construction in September 1993 and went into service in June 1994. It is operated by the privately owned National Grid Corporation of the Philippines (NGCP) since January 15, 2009, and previously by government-owned companies National Transmission Corporation (TransCo) and National Power Corporation (NAPOCOR). It was owned previously by NAPOCOR from June 1994 to March 1, 2003, and is owned currently by TransCo since March 1, 2003.
TransCo relocated its Santa Barbara Bridge–Villa del Sol segment through the Lahar-Affected Transmission Line Relocation project, using 30 replacement steel poles. It was completed in April 2003.
In 2007, 3 steel poles were relocated due to the construction of Dulalia Overpass using 2 existing steel poles (473 and 475) and 1 replacement steel pole (474). NAPOCOR-era steel pole 474 which is a suspension tower and has triangle tower design, however, was retired.
The cut-in connection to Meralco Duhat substation was constructed to avoid line overloading and maintain N-1 criterion. It was completed on November 16, 2009.
In 2010, 3 replacement and higher steel poles (381–383) were used due to the construction of Balagtas Interchange, with NAPOCOR-era steel poles 381 and 382 which are both anchor towers and have flag tower design were reused as part of Hermosa–San Jose line while pole 383 (of suspension tower or flag design) was retired.
The Hermosa–Balintawak Transmission Line Relocation project involved the relocation of its San Simon–Pulilan segment along NLEX using 58 steel poles (45 replacement and 13 existing poles) and 4 lattice towers (2 replacement and 2 existing towers). Contract effectivity of the project is on February 18, 2008. Land and right-of-way acquisition for the 4 lattice towers of the said transmission line segment which are located along Candaba Viaduct of NLEX (255, 256, 266, and 267; with 255 and 256 are replacement structures while 266 and 267 use NAPOCOR-era towers 264 and 265) were done from 2008 to January 15, 2009, during the time when TransCo is the operator of the transmission facilities, which was then followed by the land and ROW acquisition for the 58 steel poles (228–254, 257–265, 268–289; with 229–233, 237, 238, 241, 242, 244–246, 248–253, 257–265, 268–275, 277–280, 282, 283, 285–288 are replacement steel poles while 228, 234–236, 239, 240, 243, 247, 254, 276, 281, 284, and 289 use NAPOCOR-era poles 228, 229, 231, 259–261, 266, 267, 271, 276, 283, 301, and 302) from January 15, 2009, up until the completion of the project on March 25, 2011, when NGCP is now the operator of the facilities. Structures (including NAPOCOR-era structures, and structures that will be placed on TransCo-acquired and designated lands and right of way which are the lattice towers) were then later erected and built from early 2010 to March 2011. In June 2011, three months after the completion and energization of the relocated San Simon–Pulilan section of the transmission line, removal of 84 NAPOCOR-era steel poles (228–263, 266–313) and 2 lattice towers (264 and 265) as well as the retirement of 70 out of 84 steel poles (230, 232–258, 262, 263, 268–270, 272–274, 277–282, 284–300, 303–313) that were located along MacArthur Highway from San Simon, Pampanga to Caltex in Calumpit, Bulacan and Pulilan Regional Road from Calumpit to Pulilan Exit in Pulilan was completed.
One steel pole that was located near Dolores Flyover was relocated at the edge of Jose Abad Santos Avenue while the relocation of the transmission line's San Simon–Pulilan section was ongoing using NAPOCOR-era steel pole 275 which was originally located along MacArthur Highway in Calumpit and now serves as the line's steel pole 167 since 2011, while pole 167 itself was retired.
In 2019, NGCP constructed new steel pole 516 located inside Balintawak substation.