O&M

The annual meeting of the Powder River Basin Coal Users’ Group was held in association with the ELECTRIC POWER conference in early May in Chicago. Get a taste of the festivities, technical meetings, and the announcement of the group’s 2009 Large and Small Plant of the Year winners in this conference report.

Cavitation is defined as the phenomenon of forming and imploding vapor bubbles in a region where the pressure of the liquid falls below its vapor pressure. Cavitation and the resultant damage can occur in any fluid-handling equipment, especially in pumps. Technological advances in industrial protective coatings and composite repair materials have made it possible to repair pumps operating in a cavitating environment rather than simply replacing them after damage occurs. Cavitation-resistant (CR) elastomers have the ability to retain adhesion under long-term immersion, dissipate energy created under high-intensity cavitation, and provide outstanding resistance to corrosion and other forms of erosion.

The Springerville Generating Station in Springerville, Ariz. (Unit 3 was POWER’s 2006 Plant of the Year), uses two lined ponds to hold water collected from its cooling towers. With the construction of Unit 4, the plant’s owner, Salt River Project (SRP), one of Arizona’s largest utilities, wanted to increase the capacity of pumps used to move effluent from one pond to another to avoid the possibility of overflow. SRP engineers wondered if using a vertical turbine pump on a floating barge would improve managing the water levels in the two ponds.

ASME’s latest revision of its Recommended Practices for the Prevention of Water Damage to Steam Turbines Used for Electric Power Generation: Fossil-Fuel Plants, ASME TDP-1-2006, contains much important design and operating advice that is proven to protect steam turbines. However, many in the industry are not as familiar with the update as they should be. This article provides a concise overview of this critical design standard.

Reducing the minimum load at which a steam turbine can reliably operate is one way to increase revenue for marginal base-loaded units during periods of low electrical demand. For this reason, it is not unusual to see merchant plants operating at "super minimum" load levels that are well below the typical 25% rated full-load limits. However, such units are operating well outside the original equipment manufacturer (OEM) design basis, and owners may experience undesirable damage to their turbines for a number of reasons. That’s why it is important for owners to understand the trade-offs and risks that come with such operation.

Performing regular oil changes on remote generators is far from simple or cost-effective. Here’s how one firm harnessed technology to extend oil change intervals from one week to two months.

The welding of dissimilar metal joints in new and retrofit power plant boiler tubing has long proved challenging. New plants designed to operate at higher temperatures and pressures require advanced alloys and a filler metal that produces reliable welds. EPRI recently developed and sponsored the commercialization of a new filler metal. Its first application is the fabrication of boiler tubes for American Electric Power’s ultrasupercritical John J. Turk, Jr. Power Plant.

Increasingly fierce competition driven by deregulation and privatization is putting downward pressure on power plant operations and maintenance (O&M) budgets. Recently, lower natural gas prices have pushed natural gas – fired combined-cycle plants higher up in many utilities’ dispatch order in some regions, a welcome change from the twice-a-day cycling experienced by some plants during the past few years. However, with more operating hours comes more interest in plant operating availability, and that means increased emphasis on reliable gas turbine operation.

Southern California Edison’s (SCE) 2,250-MWe San Onofre Nuclear Generating Station (SONGS) recently took receipt of a new and upgraded generator rotor for one of its two Alstom steam turbine generator units (Figure 1). Following the successful installation and flawless start-up of this new rotor in the Unit 2 generator, the former Unit 2 rotor was […]

In the wake of the recent U.S. Supreme Court ruling related to cooling water intake practices at large power plants, many utilities are relieved to be off the hook as far as implementing expensive control upgrades to protect fish and other aquatic organisms.