Modesto Méndez Substation Project in Guatemala

A Critical Grid Upgrade in Rural Guatemala

The Modesto Méndez substation, located in the Petén department of northern Guatemala, was completed in 2024 as part of the country's national grid modernization initiative. The project involved installing a new 75 MVA power transformer operating at 230 kV and 69 kV, along with 34 kilometers of transmission lines and a complete overhaul of the station's medium-voltage and low-voltage auxiliary systems. From a cabling perspective, the project required significant quantities of both medium-voltage power cables rated at 15kV for feeder circuits and low-voltage cables rated at 0.6/1kV for control, instrumentation, and distribution applications across indoor and outdoor environments.

Three Obstacles That Could Have Derailed the Project

The engineering team faced three significant challenges that directly influenced their cable selection. The first challenge was environmental. Petén has a tropical rainforest climate with average humidity levels exceeding eighty percent year-round. Many cables would be installed outdoors, underground in direct-buried trenches, or inside damp conduits where moisture is constantly present. Standard PVC-insulated wires absorb moisture over time in these conditions, leading to insulation degradation and ground faults. The contractor needed cables that could perform reliably in wet, underground, and high-temperature environments.

The second challenge involved mechanical stress during installation. The cables had to be routed through underground conduits, direct-buried trenches, and open cable trays, which subjected them to abrasion and pulling stress. Cables with thin or brittle insulation were prone to hidden damage. Additionally, the installation required cables that could bend around tight corners and through congested raceways, meaning excellent flexibility was essential. The contractor also needed oil resistance because some cable pathways passed near transformer cooling systems where oil leaks could occur.

The third challenge was electromagnetic interference. With a new 75 MVA transformer and 230 kV switchgear operating near the control house, severe electromagnetic interference was unavoidable. Unshielded wires running from current transformers to protection relays would pick up induced noise, causing false trips and communication errors. The contractor required shielded control cables that could reject EMI while also meeting flame retardance requirements for fire safety inside the control house.

MV-105, and UL 44 XHHW-2 Were Selected

After evaluating several options, the contractor selected a comprehensive cabling solution from our company. For the medium-voltage feeder circuits from the 69 kV switchgear to the station service transformer, we supplied MV-105 cables rated at 15kV. These cables use cross-linked polyethylene insulation designed for 105°C continuous operation, providing additional thermal margin for overload conditions common in tropical substations. The MV-105 cables are manufactured under UL 1072 standard for medium-voltage power cables and feature a copper tape shield for fault current handling and EMI reduction. They are also rated for direct burial, sunlight resistant for exposed outdoor sections, and flame retardant for safety.

For the low-voltage 0.6/1kV power distribution applications, the contractor selected CU XHHW-2 manufactured under UL 44, the standard for thermoset-insulated wires and cables. The XHHW-2 supplied for this project consisted of large conductors ranging from 250 kcmil to 750 kcmil. These were used for main low-voltage feeders from the station service transformer to the distribution panelboard, transformer cooling fan circuits, battery charger inputs, and large lighting branch circuits. The UL 44 XHHW-2 insulation is rated for 90°C in both dry and wet locations, providing a critical safety margin for the hot and humid Petén climate. The cable carries UL 44 certification and is listed as sunlight resistant for outdoor tray sections, flame retardant for indoor safety, and oil resistant for areas near transformer cooling systems. The stranded copper construction provides excellent flexibility, allowing electricians to pull large-gauge cables ranging from 250 kcmil to 750 kcmil through tight bends and congested cable trays without damage.

Our Products Delivered to the Project

We supplied the Modesto Méndez project with three categories of cable products. For the medium-voltage feeder circuits, we provided fifteen kilometers of MV-105 15kV cables in sizes ranging from 1/0 AWG to 500 kcmil. These cables featured copper tape shielding, sunlight resistant jackets for outdoor cable tray sections, and flame retardant properties. The MV-105 cables were specifically installed on circuits that could experience overload conditions during peak demand periods.

For the low-voltage 0.6/1kV power distribution, we supplied twenty kilometers of UL 44 certificated XHHW-2 copper cable in sizes from 250 to 750 kcmil. These large gauge cables were used for the main low-voltage feeders from the station service transformer to the distribution panelboard.

What Made Our Solution Stand Out

Our success on the project came from several key differentiators. We supplied MV-105 cables with a 105°C temperature rating, which exceeded the project's base specification of 90°C. This provided an additional thermal safety margin for the tropical Petén environment and allowed for future load growth without cable replacement. Our UL 44 XHHW-2 cables featured moisture-block construction with water-swellable powder between the conductor strands. If the outer jacket was nicked during installation, the powder expanded upon contact with moisture, sealing the breach and preventing water from wicking along the cable length. This was essential for the underground and direct-buried sections of the project. Our XHHW-2 is UL 44 certified for use in open cable trays without conduit, and it carries additional listings for sunlight resistance and flame retardance. The contractor originally planned to install over twelve thousand meters of EMT conduit for the low-voltage feeders, but by switching to our tray-rated XHHW-2, they eliminated the need for conduit entirely in many outdoor and underground areas. This saved over forty-five thousand dollars and shortened the schedule by three weeks. Every reel of medium-voltage and low-voltage cable we shipped was hi-pot tested and continuity checked, with certified test reports provided. The contractor reported zero field failures during insulation resistance testing. Finally, we coordinated just-in-time deliveries through Puerto Quetzal in three phased shipments.

Proven Results in a Demanding Environment

The Modesto Méndez substation was energized in the first quarter of 2024. In the first eight months of operation, the station recorded zero cable-related failures. The 105°C rating of the MV-105 cables proved valuable during peak summer months when ambient temperatures exceeded 40°C and circuit loading was high. The 90°C wet rating of the UL 44 XHHW-2 cables proved essential during the rainy season when underground conduits remained saturated for weeks. The sunlight resistant jackets on both medium-voltage and low-voltage cables showed no signs of cracking or fading on outdoor tray sections. Installation time for the low-voltage feeders was reduced by thirty percent compared to the original estimate, largely because the flexible stranded XHHW-2 conductors in large gauges pulled easily through bends. The project manager from INDE noted that the combination of MV-105, and UL 44 XHHW-2 cables delivered reliability that exceeded their expectations, with the shielded control cables eliminating nuisance trips during lightning storms that had plagued older substations for years.

A Blueprint for Future Substation Projects

The Modesto Méndez project demonstrates that for substation applications in tropical or industrial environments, a complete cabling solution using MV-105, and UL 44 XHHW-2 cables is superior to standard PVC-insulated alternatives. The medium-voltage cables deliver reliable 15kV power distribution with 90°C to 105°C temperature ratings, copper tape shielding, and direct burial capability. The low-voltage UL 44 XHHW-2 cables provide robust 0.6/1kV power distribution with 90°C wet rating, sunlight resistance, flame retardance, oil resistance, and excellent flexibility. As Guatemala continues to expand its transmission grid with eighteen new substations planned by 2028, our medium-voltage and UL 44 XHHW-2 cables should be the default specification for all power distribution and control circuits.

Contact us

Contact us to learn how our MV-105, and UL 44 XHHW-2 products can solve your substation cabling challenges in outdoor, underground, wet, or high-temperature environments.

Tel/WhatsApp/WeChat: +86 135 1078 4550 / +86 136 6257 9592
Email: manager01@greaterwire.com