At the 2018 Ovation Users’ Group Conference, Emerson’s Jason King and John Reidelbach provided an update on Ovation Machinery Health Monitor and a case study of its application.
Jason opened describing some of the challenges of traditional machinery protection systems. Plants today have more operational issues due to cycling stresses, loss of expertise, and maintenance issues from growing reactive work practices.
It’s harder to find the time to collect and analyze the data from these traditional systems or route-based manual vibration data collection. Legacy systems also tend to provide protection and not the diagnostics to detect and avoid impending problems.
The Ovation Machinery Health Monitor solution is integrated into the Ovation distributed control system. A module supports 8 channels and these channels are software configurable for sensor types, such as an accelerometer. These channels are compatible with existing field sensors.
Jason noted that a few modules can replace existing racks of legacy protection systems and the system is designed for all rotating equipment, not just turbomachinery.
With traditional protection systems signals to and from the control system must be hardwired or via communications protocols such as MODBUS. With the Ovation Machinery Health Monitor (MHM) module already integrated into the Ovation system, only the wiring from the sensors is required.
This module works with Ovation version 3.5.1 or newer and the OCC100 compact controller.
Jason described standalone rack-based systems also available—AMS 6500 Classic and AMS 6500 ATG.
He contrasted prediction from protection. Protection occurs when the machinery is near the end of its failure curve where repairs are required. Prediction spots problems earlier where issues can be planned and scheduled to be addressed before major repairs are needed. Some of the vibration issues which may be found by predictive analytics include imbalance, looseness, misalignment, and other mechanical issues.
The analytics monitor for peak & phase readings at the multiples of the turning speed of the machinery. As data that is part of the system they can be trended, alarmed, historized and available with the process data. Another diagnostic is PeakVue that looks for impacting conditions in the bearing or gearbox.
With a reading below 10, the bearing is OK, when it crosses 10, the bearings need to be checked. When it crosses 20, the failure is near and needs to be addressed. At 30, the failure is imminent. Traditional protection systems will miss these early warnings and perhaps not prevent the point of failure.
John described a combustion turbine power utility. The site was replacing existing OEM turbine controls and updating their Ovation system to a recent release. Also, part of the scope was to replace and obsolete vibration monitoring system.
The Machinery Health Monitor modules were added to the Ovation system and the existing vibration wiring was swapped over from the old vibration monitoring system. One Ovation controller with MHM modules was used for each of the peaker generators.
