EHV POWER HAS PROJECTS ACROSS
NORTH, CENTRAL AND SOUTH AMERICA.
EHV Power has a long record of delivering high voltage underground transmission cable system projects successfully – safely, on time and on budget. We work collaboratively with clients to meet their needs with a quality, cost-effective solution. Our electrical transmission projects have taken our highly experienced and mobile work crews across Canada, the United States and into parts of Central and South America.
Central / South America
On February 11, 1999, the 300 MW Francisco Morazan Power Station located in the highlands of Honduras suffered a major ﬁre in the transformer gallery. The fire shut down the hydroelectric station causing a national emergency as half of the national power demand derived from the Power Station. The fire damaged the 230kV low pressure oil filled power cables in the vertical shaft responsible for transmitting the power from the station to the electrical grid.
The decision was made to repair the oil filled cables as placing the power back in service was a top priority. This was a short-term solution; however, the oil filled cables were eventually replaced to the modern XLPE cable insulation type a few years later. EHV Power was engaged to complete the repairs and CIDA, the Canadian International Development Agency, provided funding for the cable repair project.
One of the oil filled cable circuits would have to be sacrificed for the repair; thus, reducing the station capacity from 300 to 225 MW.
The following test were performed by EHV to ensure the cables were suitable for repairs:
• Residual Gas Pressure (RGP)
• Oil Power Factor Tests
• Impregnation Coefficient Tests
• Dissolved Gas Analysis
The repairs were completed in less than 2 months. A successful HiPot test was achieved, and the circuits were placed back into service. The re-operation of the Power station avoided power purchases and the people of Honduras benefited from an early reduction in power rationing.
TRINIDAD & TOBAGO
EHV Power installed the longest and largest 132kV underground cable circuit coming into Port of Spain in Trinidad. This installation allowed the commencement of the decommissioning of the oldest generating plant in the city of Port of Spain.
Utilizing a local civil contractor, EHV designed and constructed all the required cable vaults for the cable splicing works. For the cable installation works, EHV completed a difficult underground power cable pull into the newly constructed 132kV/33kV substation utilizing the bond pulling technique.
The project included the installation and commissioning of a Distributed Temperature Sensing (DTS) system which allows the monitoring of the cable temperature. EHV donated a Partial Discharge (PD) Monitoring offline system.
As part of the field acceptance testing, a cable jacket integrity did not pass on one of the phases. Applying EHV’s cable jacket fault locator device, the jacket damage was located at the underground to overhead transition junction. The cable jacket was successfully repaired and the 132kV underground cable circuits were turned over to the Trinidad & Tobago Electricity Commission.