The Unit 6 of the "Diez de Octubre" thermoelectric power plant (CTE) in Nuevitas, Camagüey, has once again gone offline less than 24 hours after being synchronized with the National Electric System (SEN). This unit had been under technical maintenance for 77 days.
The report from the Union Electrica de Cuba (UNE) on Tuesday indicated that Unit 6 of the CTE Nuevitas was malfunctioning. However, the National Television News (NTV) had reported on Monday that it was synchronized with the SEN after undergoing "corrective actions."
"Unit 6 of the thermoelectric plant is currently delivering more than 90 Mega Watts stably to Cuba. This block received corrective actions, primarily in the boiler area. The downtime also allowed for the resolution of failures in automatic equipment and turbine elements," NTV stated on its social media channels.
The report emphasized that "although it does not fully cover the deficit in generation capacity faced by the UNE, the restoration of Machine 6 helps reduce blackout times and increase system stability in the central and eastern provinces of the country."
"The block is gradually restoring its loads. Specialists noted that after synchronization, the machine's parameters show positive values. The boiler was prioritized in the maintenance. Authorities highlighted the replacement of elements that caused the unit's constant outages," official journalist Bernardo Espinosa reported on Monday.
Engineer Orlando Anazco Ponce de León, director of maintenance brigades at the Nuevitas Electric Power Plant, stated that "the entire economizer was replaced." The piece was manufactured by operators from the CTE Felton in Holguin and assembled by Nuevitas workers.
"We also worked significantly on the regenerative air heater, which was in very poor condition. And accompanying works were carried out over the 77 days planned for maintenance. We worked on ducts, joints, and gates," the executive added.
According to Espinosa, during the two and a half months of maintenance downtime, "specialized workshops of the Electric Power Plant Maintenance Company in the capital, along with engineers and technicians from the thermoelectric plant, undertook highly complex and precise procedures."
"We repaired six turbine bearings that also needed repair. In the case of the Regenerative Air Heaters (CAR), which were another key element, we managed to carry out significant repairs and replace all CAR baskets, successfully installing all new baskets and sealing the entire CAR in the unit," explained Engineer Jorge Luis Maceira Esteva, general director of the CTE Nuevitas.
According to Engineer Ariel Cogollos Izaguirre, the corrosion and erosion of the baskets are due to uneven wear caused by the action of combustion gases and the non-stationary temperature field established in the CAR as a result of its operation.
This uneven wear causes the baskets to be unbalanced, leading to fatigue failures. The use of 100% domestic crude oil as fuel in Nuevitas does not help prolong the effect of repairs over time.
"We also intervened in a control valve, specifically the turbine's control valve number 3, which was faulty. Additionally, we worked on the regulator system and its cleaning," added Engineer Esmeraudy Labañino, an automatic systems specialist at the CTE Nuevitas.
According to the official report, "the maintenance actions carried out are part of the intervention program to recover power, improve operational reliability parameters, and reduce unexpected outages."
Bernardo Espinosa emphasized that the intervention highlighted "the preparation, planning, control, and utilization of available national and imported resources, all aimed at the country's base generation."
Less than 24 hours after the report was issued, the same journalist interviewed Engineer Lazaro Guerra Hernandez, technical director of the state-owned company, who reported the shutdown of Unit 6 in Nuevitas.
Without providing details about the shutdown, the executive continued with his litany of breakdowns and maintenance issues, while Espinosa seemed to forget where he had been the previous day and why.
In the presence of the UNE executive, the journalist withheld information about what happened with Unit 6 in Nuevitas, while recommending that the population "stay informed through official channels."
Nuevitas Power Plant and National Electric System Issues
Below are some common questions and answers regarding the recent issues faced by the Nuevitas Power Plant and the National Electric System in Cuba.
What caused Unit 6 of the Nuevitas Power Plant to go offline?
The specific details of what caused Unit 6 to go offline have not been disclosed by the authorities. However, it was mentioned that the unit had undergone extensive maintenance and corrective actions prior to the shutdown.
How long was Unit 6 under maintenance before it went offline?
Unit 6 was under technical maintenance for 77 days before it was synchronized with the National Electric System and subsequently went offline again less than 24 hours later.
What were some of the key maintenance actions taken on Unit 6?
Key maintenance actions included replacing the entire economizer, working on the regenerative air heater, repairing turbine bearings, and intervening in a control valve.
How does the use of domestic crude oil impact the power plant's operations?
The use of 100% domestic crude oil as fuel in the Nuevitas Power Plant contributes to uneven wear and tear, leading to more frequent maintenance needs and shorter durations between necessary repairs.