Xcel Energy is spending $874,000 to add capacity to the Portales electric distribution system to remedy imbalances in the system that caused power outages in the recent bouts of extremely cold weather.
Changes in customer usage patterns and growing electrical load have overburdened portions of the Xcel Energy distribution system in parts of Portales. David Essex, manager for community and economic development in Portales and Clovis, said that, during the most recent cold spell, the load was 119 to 234 percent of the highest previous, and expected, seasonal demand.
“While utilities across the southwest experienced similar issues because of record cold weather, several hundred Portales customers had already experienced service interruptions in January caused by higher-than expected customer demand,” Essex said.
After the January outages, the company began an in-depth analysis of deficiencies in the existing infrastructure, and found that capacity improvements were needed at the substation level and also along power lines serving Portales neighborhoods, Essex said.
During the February cold spell, Xcel Energy dispatched personnel to substations that had experienced problems in January in order to prevent further outages. These employees braved subzero temperatures in the predawn hours to monitor power flow and change breaker settings to temporarily allow more current to flow. In some cases, load was switched from impacted substation breakers to other circuits as a means to prevent outages.
Throughout January and February, line fuses and transformers serving homes and businesses failed when these facilities were loaded beyond their capacity, Essex said. As these fuses and transformers were replaced, they were upgraded to a higher capacity.
The company expects to see the most improvement come from an effort to upgrade the voltage capacity in areas most impacted by the recent outages, Essex said. Some portions of the city already have been upgraded from 4 kilovolt (kV) power systems to 12 kV service. Voltage can be likened to water pressure, and these voltage upgrades are very similar to putting in larger pipes to carry more water, he said.
The company plans to move about 70 residential and commercial blocks to the higher voltage service, and then redistribute the remaining homes and businesses still on 4 kV service in order to balance the system. This work should be accomplished by this summer, Essex said.
Later in the year, Xcel Energy hopes to complete a new feeder tie line along Lime Street, which will further enhance reliability in the city.
Circuit breakers at neighborhood substations are also being upgraded to handle higher loads. One breaker already has been replaced, and five more will be replaced by year’s end. Essex said all the substation and line investments together will cost around $874,000.
“Portales is a prosperous community, and is poised for more growth,” Essex said. “The recent reliability problems are growing pains, and also the result of some unprecedented cold weather. Regardless of the cause, it is up to Xcel Energy to provide reliable service and to anticipate future customer needs. We regret that we failed to do this, and regret the inconvenience these outages have caused. We’re committed to building a better system to serve our valued Portales customers.”
Essex also recognized that customers in Clovis experienced interruptions, and were especially hard hit during the February cold spells. Most of these problems were related to overloaded transformers in the alleyways, and as these transformers failed, they were also upgraded to handle more load, he said.