WTUI, CCJ ONsite to collaborate on best practices

The Western Turbine Users and CCJ ONsite will work together to expand the sharing of best practices among owner/operators of GE aero engines. WTUI Board Member Ed Jackson, plant manager of Missouri River Energy Services’ Exira Generating Station in Brayton, Iowa, said the organization’s mission is to help members better operate and maintain their plants, and a proactive best practices program would support this objective. First step in the plan is to add a one-hour session on best practices to the Special Technical Presentations portion of the program (Tuesday afternoon), beginning in 2017.

At WTUI’s 26th Annual Meeting in Palm Springs, Jackson, and the WTUI officers, directors, and session break-out chairs, will encourage user support of the initiative and explain how owner/operators can participate and benefit from the experience. Three plants will be recognized for their best practices the 2016 CCJ Best Practices Awards during the Tuesday luncheon: Waterside, Lawrence, and Worthington. Their best practices are summarized below.

Waterside

Waterside Power LLC, an emergency oil-fired peaking plant located in Stamford, Conn, is equipped with three trailer-mounted TM2500s capable of generating a total of 72 MW. It is owned by FREIF North American Power I LLC and operated by Consolidated Assert Management Services (CAMS) with a staff of three: Plant Manager Bill Jolly and Technicians Colin Cameron and Robbie Nelson.

ISO New England requires this facility to meet the grid’s generation requirement within 30 minutes of an electronic or telephone dispatch. Important to note is that ISO-NE recently implemented much stronger penalties for not meeting the 30-min dispatch requirement and for the failure to provide reserve.

The inability of this relatively small project to meet grid needs even one time could jeopardize the plant’s future. Thus, the three best practices shared this year by the plant staff focus on reliability improvement through automation, an ongoing initiative. Since the reliability improvements were implemented, the plant has maintained a 100% performance factor and an equivalent forced-outage rate demand of zero.

Generator emergency LO system

As installed, Waterside required considerable manual intervention to operate the plant in accordance with recommended procedures. Example: To monitor and control generator bearing temperature, an operator had to start and stop the emergency lube-oil pump manually when required to maintain a start permissive. The turbines would lose their start permissive when bearing temperatures fell below the required minimum. Loss of the permissive would have had a major negative financial impact on the project.

There was another concern, too. If the system were not monitored closely, the pump would run longer than required, increasing the parasitic power draw and adding to equipment wear and tear.

The pump only had to run during peak hours when the plant was in the 30-minute reserve mode.

Plant elected to automate the system. The operations team opted to change the logic so when the units were in auto-synch mode (used only during the 30-minute reserve periods) the generator lube-oil system would maintain bearing temperature within the manufacturer’s specifications. Shutdown was initiated at a predetermined point to conserve wear and tear on the equipment, excess power consumption of AC fans and motors, and excess battery draw on the DC system.

There has not been a loss-of-start-permissive attributed to bearing temperature since commissioning of the automation feature. “Flawless” is the term used to describe the performance of the upgraded system.

Automation of fuel isolation

If a leak occurred in the fuel system provided with each of the plant’s TM2500 engines, the shift operator would not have been aware of a malfunction until a fire started or a substantial amount of fuel was lost. Because of the time it would have taken for the operator to respond, a plant shutdown was likely. With capacity and availability critical to success, plant staff investigated ways to reduce this operational risk.

A control system upgrade and the installation of a motor-operated valve on each unit’s auxiliary skid reduced the risk of loss of generation and/or equipment caused by fire or a major leak. The system is tied into the HMI and visual status of valve position always is available. The operating system alarm summary/shutdown screen was updated to accommodate the upgrades, which have performed flawlessly and reduced the operator’s time away from the control room.

Fuel building fire protection

The reliability of Waterside’s fuel forwarding system was investigated by plant staff. Reason: If system operation were interrupted, the facility would be unable to meet its dispatch requirement. The plant was designed with two 100% fuel forwarding pumps, two 100% fuel off-loading pumps, and two 126,000-gal storage tanks (one in ready reserve).

Personnel had some concerns about their ability to maintain plant reliability at the level demanded by the grid with no fire detection system installed in the fuel pumphouse. Were a fire to start, building and equipment could be lost before first responders got to the site. This would cause a total loss of generation and the ability to make the plant available for future dispatches until a temporary fuel system was in place or the existing fuel building and equipment were replaced.

Also, not having fire-detection capability meant the shift operator would have to leave his or her post periodically to visually confirm there were no issues within the fuel building. Absent the operator from the control room, there was no one to monitor plant performance and insure Waterside was meeting desired dispatch parameters.

Waterside installed a cross-zone thermal fire detection system and provided indication of system status to the local control room at each TM2500 as well as the main control room. Cross-zoning of the thermal detection system assures the plant’s fuel system would not trip from the loss of a single signal, or the failure of a single detection device, while still providing adequate system/plant protection in the event of an actual fire. When both zones are activated, the system shuts down the turbines and helps isolate all potential fuel sources—including the fuel forwarding pumps that otherwise would continue to feed the fire.

Real-time monitoring of the fuel building by the fire detection system has reduced the amount of time the operator must be away from the control room to monitor the system locally. Immediate indication of an abnormal thermal condition in the fuel building also reduces significantly the chances of a total system loss in the unlikely event of an actual fire.

Lawrence

Top hat prevents water from entering line-side cubicle

During annual inspections of the generator line-side cubicle, Lawrence Generating Station personnel occasionally found corrosion, with minor evidence of moisture intrusion. Staff inspected and replaced door gaskets as necessary, but snow accumulates on top of the cubicle during winter and the melt-off leaked into the interior, as indicated by water stains. Concern was that with an increase in wintertime dispatches, additional protection was required to guard against corrosion and potential arcing failures.

After evaluating the risks, Lead O&M Technician Matt O’Hara, O/M-ICE Tech Robert Bauman, and O&M Tech Jared Thomas collaborated to identify an effective way for preventing snow accumulation on the cubicle and water intrusion. The “top hat” design—in effect a single chevron—made by a local metal fabricator was the solution. Since the top hats were installed, inspections have revealed no evidence of water intrusion; the tops of the cubicles are dry and snow-free. The additional protection will extend component life and prevent a possible catastrophic failure caused by arc flash.

Lawrence is an LM6000-powered, 258-MW, 6 × 0 gas-fired peaking station located in Lawrence County, Ind, co-owned by Hoosier Energy (four units) and Wabash Valley Power Assn (two units). Robert VanDenburgh manages the facility for NAES Corp, the contract operator.

Worthington

Safer, faster chiller winterization

Hoosier Energy’s 174-MW Worthington Generating Station, a 4 × 0 gas-fired peaking station powered by inlet-chiller-equipped LM6000s, was designed to operate from April through October and later modified for year-round peaking power. Wintertime operation required lay-up of the chillers, plus freeze protection of the chilled-water system by use of a glycol/water mixture and an auxiliary boiler.

Each spring and fall, Worthington personnel had to change out the glycol solution for summer and winter operations, respectively. In winter, the fluid contains 35% glycol, in summer less than 10%. The change-out procedure used since the plant went commercial, which involved the transport of glycol solution by tote, restricted plant operations, was associated with safety and environmental risks, and was expensive (it could take three operators up to four 12-hr days to change out the glycol).

Worthington staff—specifically Plant Manager Robert VanDenburgh, Lead O&M Tech Matthew O’Hara, O&M Tech Bruce Button, and O&M/IC&E Tech Jason Robertson—collaborated and developed a new procedure requiring a few plant modifications. Details are available in the WTUI program guide distributed at the conference by CCJ.

Today, two operators can perform the new procedure in only about eight hours (total of 16 man-hours), meaning the plant can be restored to full operation in a single shift instead of the four full days it used to take (144 man-hours, 40% of that at the overtime rate). The new procedure completely eliminates the safety and environmental hazards associated with the original.

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