ECI/EPCS were contracted to provide turnkey EPC services for the Laredo STATCOM Substation Project. ECI’s scope of work included the 41.6 kV ±150 MVA STATCOM replacement at the existing Laredo site.

The design included the following equipment:

• Three (3) RCVTs for accurate harmonic measurement
• Two (2) 138kV, 167kVA, SSVTs configured in an open delta configuration to mitigate any circulating currents
• One (1) active 138/41.6 kV, 120/150 MVA three-phase transformer, plus one (1) de-energized spare transformer. This included a delta configured secondary for the STATCOM connection.
• One (1) active 41.6kV grounding transformer, plus one (1) de-energized spare transformer. This was used to detect any ground faults in the system.
• Three (3) 138kV, CCVTs, three (3) 41.6kV, PTs, three (3) 69kV CTs
• Three (3) 69kV, current limiting reactors located in the delta of the STATCOM configuration.
• Two (2) 69kV, switches. One located in the yard, and one located inside the STATCOM building.
• Three (3) 69kV, surge capacitors
• Three (3) wall 69kV wall bushing, with AC & DC CTs mounted on the wall bushings.

The STATCOM was wired in a delta configuration that required non-traditional differential protection scheme. There was also a unique phase-over-phase bus design that was utilized due to space constraints.

The STATCOM building was designed to house a stacked STATCOM design in addition to a pump skid and the traditional control panels. Additionally, the building was designed with wall bushings to transition the outdoor energized bus to the interior STATCOM disconnect switch. Consequently, the building was up to 24’ in height with pad-mounted HVAC units due to the large amount of heat loads generated by the equipment.

ECI collaborated on this EPC project with HICO for AEP. This was a critical piece of infrastructure in the AEP system and therefore also required a 200kVA UPS to keep the critical cooling components running during any AC outage.