The Sucat–Paco–Araneta–Balintawak Transmission Line (abbreviated as SA, 8LI1QUE-DIM, 8LI1DIM-MNA, 8LI1MNA-MUN, SPABTL) also known as Muntinlupa–Manila–Doña Imelda–Quezon Transmission Line, commonly known as Sucat–Balintawak 230kV and formerly known as Sucat–Araneta–Balintawak Transmission Line from July 2000 to October 2012, is a 230,000 volt, single-circuit, three-part transmission line in Metro Manila, Philippines that connects Sucat and Balintawak substations of National Grid Corporation of the Philippines (NGCP), with line segment termination at NGCP Araneta substation in Quezon City and Manila Electric Company (Meralco) Paco substation in Paco, Manila.
History The Sucat–Paco–Araneta–Balintawak Transmission Line began construction in 1996 and went into service in July 2000 which took four years to complete because there is a right of way (ROW) or alignment constraints. The line was constructed to increase the transmission output in the urban grid in Metro Manila to cover the increasing demand for electricity and a contribution was to be made to ensuring a continuous supply of electricity and to the macroeconomic objectives of growth and employment, and to address the Luzon power crisis from 1991 to 1993. It is one of the shortest transmission lines in the Philippines with its 34 kilometer span. The transmission line has four substations to connect but the ROW needs to be flexible which is the reason why the line uses the Skyway Stage 3 ROW. The electrical current heads south because the Hermosa–Duhat–Balintawak transmission line connects to Balintawak substation making the power line third of five lines forming the transmission network from Bataan Combined Cycle Power Plant (BCCPP) in Limay, Bataan to Calaca Power Plant in Calaca, Batangas and six to Mak–Ban Geothermal Power Plant in Santo Tomas also in Batangas and Bay in Laguna, and its frequency is 60.14 Hz (every transmission line in Philippines have 60 hertz). There are no loads measured but the information, was not publicly available.
With the construction of the Skyway Stage 3, several steel poles are being replaced by newer ones specifically those along the Araneta segment and also added new poles on certain portions of the line. The newer steel poles were made of porcelain discs (15) and 3 horizontal pole-mounted porcelain insulator. Since the construction of Skyway Stage 3, the newer design is flag design with the deadend insulators (made of polymer/porcelain)
As of 2016, the base of the transmission line segment of Sucat–Paco, Paco–Araneta, and Araneta–Balintawak segment have a large and tall circular pile with the National Grid Corporation of the Philippines (NGCP) new reflective reference tag (Araneta–Balintawak) and NAPOCOR/NPC steel pole and lattice tower numbers with NGCP's reference tags since 2015 on the Sucat–Paco and Araneta–Balintawak segments.
Route description The Sucat–Paco–Araneta–Balintawak Transmission Line passes through the cities of Muntinlupa, Taguig, Makati, Manila, and Quezon City. The Sucat–Paco and Paco–Araneta segments are under NGCP's South Luzon Operations and Maintenance (SLOM) District 1 (South Western Tagalog) while the Araneta–Balintawak segment is under North Luzon Operations and Maintenance (NLOM) District 7 (National Capital Region).
Sucat–Paco The transmission line starts at Sucat Substation where it parallels Manuel L. Quezon Avenue and Laguna Lake Highway before it turns left. It then passes to Diego Silang Village and parallels with Carlos P. Garcia Avenue. It goes to the left again, passing through Manila American Cemetery and Bonifacio Heights before paralleling to South Luzon Expressway (SLEx) from Maricaban Creek to Magallanes Interchange and Osmeña Highway from Magallanes Interchange to Quirino Avenue. At Magallanes Interchange, it crosses to Epifanio delos Santos Avenue (EDSA). It continues on a straight route and after crossing Gil Puyat Avenue are 7 new steel poles that were used for the relocation of the line due to the construction of Skyway Stage 3. It crosses to San Andres Bukid and Paco. Near Paco Substation, the two broader Meralco transmission steel poles and one belonging to Sucat–Paco–Araneta–Balintawak line itself anchoring it before entering Paco Substation. The cut-in connection to Meralco Paco substation is located in this district, where the line's Sucat–Paco section ends.
Paco–Araneta The line parallels to Tomas Claudio Street (or Paco–Santa Mesa Road), PNR Metro Commuter railroad and Magsaysay Boulevard, turns left to Gregorio Araneta Avenue and run parallel with the said avenue and Skyway Stage 3, and the line's Paco–Araneta section ends at Araneta Substation.
Araneta–Balintawak The line continues paralleling Araneta Avenue and Skyway Stage 3 until it passes to Valentin Ventura Street, Tuktukan Street, and Kaingin Road before it crosses to EDSA. It turns left and after a few meters is the transmission line's terminus which is Balintawak Substation.
Technical description
Engineering The chief engineer of the line were never fully disclosed. Based on the KfW report, the line had several right-of-way (ROW) acquisition delays during the land acquisition stage of the line. With the Skyway Stage 3 construction cost of ₱55.63 billion, it likely involves NGCP to reheight and relocation of poles alongside the alignment affecting the Stage 3's ROW (alongside G. Araneta Avenue and along near Osmeña Highway given the utility relocation for all affected Meralco and NGCP-owned poles have a total cost of ₱798.25 million.
Design
Original design The original design almost uses the "flag" design poles except one in Araneta substation, which uses irregular wishbone-based design. It uses Hermosa–Balintawak 230 kV design as a reference though there are variations: the post insulators of every anchor poles are not adjacent (located few centimeters down from the strain insulators) and the suspension poles have now a pole Harm at the disc side rather than thick rod used in HB 230 kV. This design still being used to this day though they were relocated and as a legacy to that National Power Corporation (NAPOCOR/NPC)-era design framework. Most of the insulator mounting systems was a direct mount with preformed brackets at steel pole segments (whose pole ends segment system was friction-based attachments and are tapered).
Skyway Stage 3 poles Prior to the Skyway Stage 3 construction and utility relocation, the then new National Grid Corporation of the Philippines (NGCP)-era poles are all of "flag" design, featuring the four-armed (4) anchor poles and NGCP-era direct mount anchor poles (same as the original design but the spacing is more compact yet tall). However, the legacy design was still used, each of them had legacy hardware that was formerly used by the NPC though the pole end segment attachment system was bolted.
Hardware
Suspension insulators The NAPOCOR/NPC-era suspension insulators features a V-shaped horizontal assemblies (commonly known as braced line posts). The 230 kV rated suspension discs acts as a lateral support that resists from the vertical resultant forces (Vf) and a 230 kV rated post insulator acts an strut that resists from the horizontal resultant forces (Hf). Just like with the original design, the attachment point for the insulator string was a preformed bracket in order to avoid a joint snap under live load (the conductors themselves). The base of the insulator design was Hermosa–Balintawak 230 kV and other predecessor 230 kV power lines. While NGCP-era poles had now I-string insulators in the four-armed design, the latter serves as a legacy from the NAPOCOR/NPC design framework. Most material used for all insulators are porcelain/ceramic but there are few polymer variants.
Strain and post insulators
Dead-end/strain insulators Same as other 230 kV lines, though the clamps were now conductor tie-in clamps or gun-shaped clamps.
Post insulators With the dead-end/anchor pole design, the placement of the post insulator is few centimeters down from the dead-end or strain insulators. The material is porcelain, in par of the insulator material used.
All of the insulator strings and braced line post insulator assemblies feature corona rings.
Inventory The transmission line consists of 219 steel poles (53 on the Balintawak–Araneta segment (1–53) and 167 on the Araneta–Paco and Paco–Sucat segments (1–8, 30-149, 150A, 150B, and 155–185)), 26 lattice towers (9-29, 150, and 151–154), and 1 portal tower located between steel poles 49 and 50 ((8LI1MNA-MUN)97) totaling to 246 transmission structures. Steel poles have flag tower design (suspension and anchor variants), while lattice towers have incomplete tower design. Portal towers are used on portions of the line where it intersects with another power line. It has a length of 34 kilometers (21 mi) and is a single-circuit, double-bundle power line.
Elevation The highest elevation segment are the Paco–Araneta and Araneta–Balintawak segments, utilizing the Skyway Stage 3 and steel poles are 60-70m tall.
Storage space for structures retired from original use and ownership The National Power Corporation (NAPOCOR/NPC)-era transmission structures that were retired from original use and ownership because of various projects made by National Grid Corporation of the Philippines (NGCP) on the line were stored on various substations for those unused for a while. Most people know that the unused retired structures are stored in a structure's graveyard but it is not. They are stored in various substations for future other uses with their new ownership.
+Electrical Information of Sucat–Paco–Araneta–Balintawak Transmission LineSegmentCurrentVoltsHeadingSucat–Paconot measured230,000SouthPaco–AranetaAraneta–BalintawakRelocated and added steel poles segments due to construction of Skyway Stage 3 and NLEX Connector +Bundle informationBundle type and segmentSpacersAmpsBroken spacersSucat–Paco–Araneta–Balintawak (other segments)500 +not measured0Relocated and added steel poles segments due to construction of Skyway Stage 3 and NLEX Connector)300 +not measured0 +Components and lengthSegmentNumber of structuresLengthAraneta–Balintawak53 steel poles5.67 kmPaco–Araneta44 (39 steel poles, 5 lattice towers)5.92 kmSucat–Paco149 (128 steel poles, 21 lattice towers)22.24 km