Landslide to blame for major power outage

Entornointeligente.com /

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.

LINK ORIGINAL: The Trinidad Guardian

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