Circuit problems lead to CUC outages in BT

CUC headquarters in Sparkys Drive.

Problems with Caribbean Utility Company’s two new $85 million diesel generators are responsible for at least seven power outages in the Northward area since mid-April.

The company has apprised utility overseer the Electricity Regulatory Authority of the problem, and engineers from generator manufacturer MAN Diesel and Turbo of Augsburg, Germany, have summoned two specialists to help remedy the fault.

Company engineers blamed “Bodden Town circuit 15” for the outages, saying problems with the link between the new North Sound Road generators and Bodden Town and Lower Valley were due to “under frequency after a trip of one of the new units due to a communications error on the control system of the engine.”

They added that the BT15 circuit was experiencing a number of outages “because of sensitive settings of the under-frequency protection on that circuit.”

The BT15 link, engineers said, carried between 100 amperes and 200 amperes, “depending on the time of day,” acknowledging “this is a normal amount well within design parameters of the circuit.”

“Under frequency,” they explained, occurs “when there is shortage of supply, such as when a generating unit trips offline [and] the system frequency will dip for a few seconds.”

The resultant “communications error,” engineers said, “refers to a data communications link between two modules that control the particular generating unit, losing connection for a few seconds.

“It is important to always have communications in place to control the engine for safety reasons. If there is a loss of this communications’ functionality, the engine shuts down for safety reasons.”

Northward resident Jacky Walton complained to CUC and the ERA about serial outages in the area, saying they had persisted for at least one month, “lasting from 15 minutes to as long as two hours,” frequently at night, compromising both her own safety and that of a relative.

“I live in Crysdel Road, my cousin lives in Mike Watler Crescent and our gardener lives near the prison, in Northward Road,” she said. “The entire area is affected. It happens at night, although I would not necessarily know about the daytime, when I’m at work.”

She said she had been caught several times at night when “my garage doors were open, so I have to stay up until the power comes on again. What might happen, though, if the doors are down and I had an emergency? I couldn’t get out of the house.

“There are a lot of people, though, with medical conditions,” Ms. Walton said. “My aunt sleeps with an oxygen machine, and when the power goes off, she can’t use it.

“Of course, the air-conditioning goes off too, and I can’t sleep, but the worst [problem is] my aunt,” Ms. Walton said.

CUC acknowledged the outages, listing the dates and durations of more than half-a-dozen interruptions. BT15, engineers said, “sustained seven full-circuit outages this year, with five outages experienced in June.

“These occurred on: April 17 at 3:35 p.m., duration 14 minutes; June 6 at 11:40 p.m., duration 10 minutes; June 10 at 6:21 p.m., duration 19 minutes; June 12 at 12:14 a.m., duration 16 minutes; June 19 at 9:49 a.m., duration 10 minutes; June 29 at 3:36 a.m., duration 51 minutes; July 3 at 12:36 p.m., duration 22 minutes.

“Our partners MAN have been troubleshooting on site and have called in additional expertise, with two specialists arriving on island earlier [last] week to resolve this issue,” a CUC spokesman said. “CUC will be rotating the BT15 circuit off the under-frequency list until the issue is resolved [and] will run the two new units at lower loads to reduce need for backup capacity should they trip.”

On June 21, CUC formally activated two medium-speed MAN Diesel 18.5 megawatt diesel generators, alongside a 2.7 MW steam turbine.

They described the new units as “very sophisticated,” involving a multitude of sensitive monitors, checks and balances. “From time to time, communications systems of all types experience issues.”

The April and early June outages occurred as CUC tested the units before commissioning, while BT15 “is experiencing a number of outages because of sensitive settings of the under-frequency protection on that circuit.”

The company was unable to say, however, when the problems might be resolved: “CUC and MAN have already implemented a solution and we are monitoring the performance. Additional analysis will be done to see if any additional solutions are needed to ensure that the communication system is operating in a robust and reliable manner.”

The new units remained under warranty, meaning remedial work was unlikely to result in costs to CUC or its consumers. The call for specialist help from MAN did not indicate particular difficulties, the CUC spokesman said,

“Additional expertise only refers to a service technician from the original equipment manufacturer. This does not indicate any scale of the problem, only that the appropriately qualified individuals are working on it.

“Currently, CUC and MAN are putting all of the necessary resources in place to address these issues and we are confident they will be resolved quickly,” the company spokesman said.

Ms. Watler said CUC’s customer service department told her the problems were due to “a generator transfer problem,” but did not indicate a resolution, while ERA Deputy Managing Director Louis Boucher said he was meeting CUC representatives.

Authority Managing Director Charles Farrington said he was monitoring the problem, but was unable to predict when it might be resolved.

“The ERA is aware of the situation and believes CUC has taken reasonable steps to both resolve and mitigate the problem,” he said. “The ERA will continue to monitor the resolution of this issue.”