A landslide triggered a chain of events that knocked out power to thousands of homes across Trinidad on Tuesday night and then again yesterday morning.
The Trinidad and Tobago Electricity Commission (T&TEC) indicated that a landslide in Grant Trace, Rousillac, led to a 220-kilovolt transmission tower shifting, putting excess strain on high voltage lines and resulting in a partial collapse of the tower and lines at 7 pm on Tuesday.
Load-shedding was immediately implemented, leading to sporadic outages across Trinidad on Tuesday night.
According to the commission, up to 30 per cent of its customers were taken offline. With the fault at the tower, Trinidad lost power from the Trinidad Generation Unlimited (TGU), Trinidad’s largest power generation plant. Independent Power Producers (IPPs) began providing T&TEC with additional capacity to make up for the shortfall, but delays in getting generators online led to most areas having supply restored by 1 am.
However, with increased power demand by yesterday morning, rolling load-shedding was instituted across Trinidad again, leading to additional outages lasting several hours.
According to T&TEC, these reduced loads allowed them to begin the initial phase of repairs, minimising the need for rolling load shedding over the next few days.
T&TEC has already started to install several 30-metre poles and attendant lines to bypass the compromised transmission tower.
Trinidad is still not in the clear, as the commission says a few brief outages are still possible as repairs continue.
T&TEC’s general manager Kelvin Ramsook said yesterday that they expect to return to complete normalcy by later today.
Troublesome 220-kV circuit
If the 220-kV transmission line or circuit sounds remotely familiar, it is to readers.
The 220-kV Union Estate-Gandhi Village line circuit was first brought into the limelight months ago, when a fungus-affected Palmiste tree fell on a 12-kilovolt line, which led to it contacting the higher voltage 220-kV line. This contact led to a fault developing, knocking out Trinidad’s entire electrical grid in 3.6 seconds, causing a 12-hour blackout on February 16 this year.
This 10-year-old circuit is part of an electrical highway that moves power generated from TGU in La Brea to Trinidad’s grid, according to Ramsook. Ramsook explained, “Anytime we have any items that affect the infrastructure, we are unable to provide the full capacity onto the grid.” While there is a smaller “back door” circuit, it can only transport 66 kilovolts, which is unable to compensate for the Union Estate-Gandhi Village load.
February’s outage was triggered between transmission towers #53 and #54, while Tuesday night’s outage resulted from a critical failure of tower #58. Tower #58 was located metres away from the unfinished portion of the Solomon Hochoy Highway extension to Point Fortin, where land slippage in the vicinity of the tower was reported to T&TEC by NIDCO workers on Monday.
According to Minister of Public Utilities Marvin Gonsalves, T&TEC was informed sometime between Monday and Tuesday about the land slippage and was putting things in place to deal with the movement. However, the commission “did not anticipate the rapid nature of the movement.”
However, Ramsook was adamant that this failure was not a result of sabotage.
“I can tell you clearly from where I sit that is not an issue. Definitely, there is the issue of land movement and clear evidence here at the site of that land movement.”
Arising out of the February 16 islandwide power outage, T&TEC began to explore and implement plans to prevent a re-occurrence. Ramsook explained that there are efforts already underway.
“We have a programme for a second double circuit line because this line existed for over ten years, and that contract has been issued and that project is well in place and in progress.”
The second circuit is tentatively expected to be completed on January 22 next year. Ramsook added that as part of the project, a new tower will eventually be installed at the site of transmission tower 58, which failed on Tuesday.
