Entergy christened its Performance Monitoring and Diagnostic Center several years ago to leverage the expertise of its most senior operators and technicians across the company’s entire fleet of plants. The center also makes use of advanced software tools that increase plant availability and reliability by identifying faults before they become major, unplanned outages. The center paid for itself for years to come with a single “big catch” last year. Entergy has a long history in plant performance monitoring, beginning with the first implementation of its Operations Information System (OIS) over a decade ago. The introduction of market competition for reliable, low-priced power initially drove the investment in new data collection and evaluation tools at the plant level.
About the same time as the OIS was introduced, Entergy embarked on a best-in-class evaluation of its entire fleet. One result of that study was an adjustment of appropriate plant staffing levels that was based on only routine plant operations and maintenance, to reflect the industry’s long-term readjustment to a market-driven power supply system. The bottom line: Plant staffing was reduced to minimum levels during those early days of market competition.
The OIS at the time was a simple menu-driven program used to facilitate access to plant performance databases collected by OSIsoft’s PI Historian software. General Physic’s EtaPro, used for thermal performance calculations, rounded out the software toolbox available to the predictive maintenance (PdM) staff.
Unfortunately, the same initiative that reduced the O&M staff also reduced the use of the OIS system and other PdM maintenance tools so vital for monitoring plant equipment health.
Get it together
By 2001, Entergy had decided to reexamine the business case for a centralized Performance Monitoring and Diagnostic Center (PM&DC) to capture the expertise and leverage the skills of senior plant O&M professionals across its fossil fleet of 18 key power plants. Entergy also was not immune to the aging workforce pains that have hit virtually every utility, so it was seeking to leverage a shrinking cadre of highly seasoned power plant operations experts.
Entergy subsequently gave the centralized monitoring concept a green light, and the PM&DC was staffed and commissioned in 2002. The PM&DC was created in The Woodlands, Texas, a half-hour drive north of Houston. Its mission is to “support plant objectives to achieve fleet commercial excellence through improved unit performance, equipment condition, and operational risk management” (see sidebar).
According to Gary Barnes, superintendent of Entergy’s PM&DC, the center completed its sixth year of providing 24-7 coverage of routine monitoring and diagnostics the end of July. The OIS and PI systems still are the primary means of accessing plant data, but the center’s experts’ problem-solving is greatly enhanced by a suite of custom performance evaluation tools, including the latest version of SmartSignal’s EPI*Center, for early detection of performance anomalies and data mining.
PI servers are now located at 18 plants, and the OIS is at 36 units in the fleet. Special purpose utilities have been developed to further facilitate data extraction from PI for analysis. Barnes noted that the PM&DC has a strong can-do attitude, thanks to its seasoned staff, a full suite of software tools, and an in-house maintenance management system that tracks center activities.
The center also has implemented an alarm system for key performance parameters of critical equipment at each plant. Real-time performance monitoring and diagnostics through pre-built PI-Process Book displays and General Physics EtaPro have also been implemented in the PM&DC. Custom process books and data links have been built for trip analysis, unit/equipment problem diagnostics, and special monitoring. RBMWare is used by the PM&DC staff to access detailed vibration data.
Entergy recently upgraded its PM&DC to SmartSignal’s EPI*Center (see “Making PM systems sweat the small stuff,” POWER, May 2008), which provides a significant improvement in capability and performance with data access speeds that are up to five times faster. EPI*Center eases the model construction and maintenances task and allows links to other reference data such as drawings.
Anomaly detection and alerting via advanced pattern recognition (APR) software using SmartSignal’s EPI*Center, which pulls near-real-time data from the plant PI servers, is installed on 36 units. APR software filters data for subtle changes in parameter values or trends and alerts the PM&DC staff when they occur. The important difference is that these alerts occur much earlier than the plant’s standard supervisory systems alarm setting would, giving operators more time to react when a critical event occurs (Figure 1).
1. Early detection is the key. Early detection of impending equipment failures requires a custom mix of specialized software tools and highly experienced operating and technical specialists. The Entergy PM&DC routinely identifies equipment problems before the plant’s supervisory instrumentation reaches alarm limits. Source: Entergy
In addition to the software toolkit just described, a member of the PM&DC staff attends the morning Entergy dispatch meetings to gain perspective on system issues plus future dispatch plans, unit testing, outages, and the like. The PM&DC maintains a daily list of units to be started up, shut down, or tested, and a generation status page for all units in the fleet; it also responds to alerts of unit start-ups, shutdowns, and operating derates. The PM&DC even has connected to the company’s automatic generation control system to get real-time notification of unit trips (breaker trip alarms) and other important data.
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