New Options For Condition MonitoringGE Energy’s Measurement & Control Solutions has introduced two products targeting condition monitoring
by brent haight
GE’s Bently Nevada product line has introduced the 3500 Encore, a condition monitoring system for upgrading existing 3300 monitoring systems that does not require customers to perform a complete system replacement. “3500 Encore is the only non rip and replace condition monitoring solution on the market for upgrading 3300 systems,” said Don Marshall, global marketing leader-CM, at GE Energy’s Measurement & Control Solutions.
“The EMI cage design and high-speed backplane provides GE’s Bently Nevada customers with the ability to upgrade to 2011 digital technology without changing the current infrastructure. The 3500 Encore provides the same continuous, online monitoring suitable for machinery protection applications as the 3300 system with the improved performance of 3500 technology.”
The Measurement & Control Solutions business within GE Energy specializes in advanced, sensor-based measurement, nondestructive testing, inspection and condition monitoring solutions for a wide range of industries, including oil and gas and power generation. “The 3300 system was released in 1987,” said Landon Boyer, product line manager for GE’s Bently Nevada. “Over the years it’s become the standard vibration system in the world. The problem we faced is that it’s based on electronics that we can’t get parts for anymore. In the meantime, we came out with a new system called the 3500 system. It became the state-ofthe-art system and actually, over the course of time, has outsold the 3300 system to become the new standard. But for various reasons, some customers held on to the 3300 technology.
The 3500 Encore allows current 3300 users to upgrade to the latest technology while protecting and extending the life of their original investment. We are able to hold the analog piece and put a whole new digital front end on it. It is the latest technology but we are able to leverage the installed system that is already in place.” The 3500 Encore system uses the existing 3300 rack, I/Os, power input module and relays; therefore, no cabinet or wiring modifications need to be made.
“What is significant to our customers is the time savings,” said Boyer. “A rip and replace might take a week. You can only do it during a major maintenance window. Installing the 3500 Encore takes less than eight hours.” The 3500 Encore System is intended for continuous, permanent monitoring of rotating and reciprocating machinery in a variety of industries, including power generation and oil and gas. It is specifically designed for use in auto-shutdown machinery protection applications and, according to Boyer, is ideal for such installations as offshore platforms, compressor or pump stations, emergency generators and other locations where on-site access to the instrumentation is inconvenient or impractical.
The system’s design consists of an instrument rack, ac or dc power supply, TDI system monitor and monitors with full-color LCD displays chosen for the required application. The rack depth is 424 mm. The 3500 Encore chassis supports 8P, 10P and 12P 3300 rack upgrades. The chassis consists of an EMI cage, backplane and interface modules. The interface modules are installed between the old backplane and the new backplane. “These are used to reduce the likelihood of damaging the old backplane during the upgrade process and as part of the shielding for the new system,” said Boyer. The upgrade rack provides slots for a single power supply and a system monitor. The remaining slots in the rack can accommodate any combination of monitors. All modules plug into the chassis’ new backplane and consist of a main module and leverage the existing I/O module.
The power supply can be ordered for ac or dc input power, providing compatibility with voltage sources worldwide. Line noise filters are standard. The power supply module has self-monitoring functions that allow it to determine if all its output voltages are within specifications. Modem, WAN or LAN connections allow the user to remotely configure a 3500 Encore system and even assess the system when an instrument problem arises. Users can implement simple changes, such as to an alarm setpoint or a filter corner, without traveling to site.
The 3500 Encore System incorporates two levels of password protection combined with a keylock for configuration changes ensuring that the system can’t be adjusted, changed or configured except by those authorized to do so. The 3500 Encore rack records any configuration changes in the system’s event list. The 3500 Encore is designed to meet the requirements of the American Petroleum Institute’s API 670 standard.
Anti-Surge Control Technology The OptiComp BN is the latest in the OptiComp integrated compressor controls software suite providing integrated anti-surge protection and capacity control from the Control Solutions product line. OptiComp BN combines anti-surge protection with GE Energy’s Bently Nevada vibration monitoring solutions. “One of the biggest issues on a machine is surge,” said Nauman Islam, oil and gas team leader, North America, Optimization and Control. “Typically you’ve had a control system looking at process measurements. In addition to that, you’ve always had a vibration system looking at the vibration of the machine for surge. For the first time we’ve combined that technology together and really provide better protection by identifying surge sooner.”
OptiComp BN helps identify incipient surge using both thermodynamic measurements and mechanical vibration measurements, alarming users and allowing the control system to take action before the onset of a full surge event. This enables plants to operate compressors and process closer to the “optimum” point without surge, providing protection over the full range of operation, maximizing process efficiency.
OptiComp BN provides detection and avoidance of incipient surge and surge in centrifugal and axial process compressors by using the correlation between vibration and thermodynamic thermodynamic measurements. The Bently Nevada 3500 monitor identifies the subsynchronous radial vibration and supplies the detection signal to the OptiComp BN system, residing in the GE Mark VIe controller. The system correlates the appearance of the subsynchronous vibration to the location of the operating point on the compressor map and ascertains the likelihood of an incipient surge. In the case of high likelihood, the system provides an alarm and, optionally, may relocate the surge control line so as to avoid the incipient surge region.
“The essence of what we’ve done is we’ve recognized that radial, sub-synchronous vibration gives us a better indication of surge sooner, which is what we call the insipient surge region of rotating stall,” said Islam. “Traditional process measurements start to detect the surge where the flow drops. At this point in time is when a traditional surge control system would respond to protect the machine. In reality, what we’ve found is that we can see the onset of surge in the radial vibration signal which is well before, almost 400 milliseconds before, the actual surge control. In the surge world, a surge happens in the time-stamp of 40 milliseconds. So we are able to look almost 10 shots before the event and take action. “This is a huge shift in customer expectation,” added Islam.
“We responded to what a lot of companies have been asking us. We actually sense surge from vibration before process instrumentation acts on it. So we’ve now got the technology to respond. A problem a lot of our customers face is false surge. The process instrumentation says the unit is in surge but it is not, and it starts to take action. Unfortunately, many times the action results in a trip in the process. Now we can verify process shows surge, vibration shows surge, we are in surge. “Surge has always been thought of in absolute terms. ‘We surged the machine.’ For the first time, with the actual vibration signal, we can calculate the severity of surge.”