EPCOR shares follow-up report on electrical damage that shut down Edmonton WTP

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In an incident follow-up to municipal officials in Edmonton, EPCOR’s plant director at the E.L. Smith Water Treatment Plant said that it took a crew of about 30 workers an entire work week to address the fallout and repairs stemming from water-damaged electrical cables in February. 

Water had seeped into the plant’s underground vault containing high-voltage cables that supplied power to the distribution pumps, Plant Director Vicki Campell told Edmonton’s Utility Committee on March 4. The incident led to an approximate four-day water ban for Edmonton and the surrounding region as EPCOR worked to get the city back on track with its water supply.  

The committee heard that steam was observed in the electrical room above the vault where the water entered, causing damage to the electrical equipment.  

The plant’s Director of Engineering and Technical Services, Craig Bonneville, told the committee that the cables did not have adequate protection to shield them from wet environments. Specifically, a splice on the cable was not insulated. The presentation to council specified that the cables were improperly installed decades ago and hidden from view. 

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“While it is expected to have some regular seepage in this area, in this case, a seal failed,” said Bonneville, who noted that additional monitoring sensors have now been added to the vault.  

At about 10 p.m. on the first day of the incident, they were able to get the plant’s smaller 2,000 horsepower pumps active again as there had been no water damage to those cables.  

The damaged equipment and cables were removed by EPCOR and contractor teams. One contractor was able to rebuild a lot of the inside of the electrical cabinets.  

The primary cable was able to be replaced at 6 a.m. on Thursday morning. By the next morning, on Friday, the reservoirs had reached 53% and the water ban was lifted. 

The morning after the incident occurred on January 29, Campbell said that around noon that day the team realized that they had a significant situation on their hands. It was at that same point that they declared a mandatory non-essential water ban. The customer engagement and communications team began immediately reaching out to large commercial and regional customers to reduce the largest impacts on water usage. 

Within six hours of the ban being announced, direct communication had been made with more than 260 large customers. Throughout the ban, EPCOR was alerted of 30 reports of non-compliance. Overall, there were some 100 million litres of water saved over four days, equating to an approximate 10% reduction in overall water use.  

“The community made a huge difference in this event and every drop did count,” Campbell told the committee. 

The high-voltage electrical equipment that feeds the high-lift pumps has actually been identified for a life cycle replacement by 2026. The new system will provide greater redundancy monitoring capabilities and operational flexibility, Bonneville said. The equipment will be housed in a new building and physically separated from water storage chambers,  reducing the risk of future leaks.  

The plant will also be building an additional high-lift pump house that can provide further redundancy and pumping capacity.  

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