Chemicals manufacturer BASF has implemented a proactive solution to solve humidity issues in transformers, bus ducts, medium voltage switchgear and motor control center (MCC) lineups. The inherent design of arc-rated equipment limits air flow in and out of the gear. This can lead to excess humidity buildup within the gear. This buildup has the potential to cause electrical faults, and can cause significant unscheduled outages.
BASF implemented Emerson IntelliSAW technology to continuously monitor its critical electrical assets. "We have the motor and cable connection down pat," said Joel Logue, E&I engineer, power systems, at BASF. "It's the device connecting the motor and cable that we needed to monitor. The IntelliSAW system filled the void and gave us the data to understand the full health of our switchgear."
The application didn't have a lot of solutions available to monitor assets, continued Logue. "In other industries, you can monitor every little piece, and there is a lot of information you can pull from instrumentation," he said. "However, at a higher level, power-system-wise, it's not there; nobody is focused on it. Fortunately, Emerson acquired a company that provided a unique solution and showed us how to implement it. The system showed its value to our organization by reducing preventive maintenance."
IntelliSAW fills sensing gap
IntelliSAW technology fits in well to the pervasive sensing methods talked about all week at the at the Emerson Global Users Exchange in San Antonio, said Chris Short, Emerson’s field sales specialist, Rosemount Measurement. "It provides a system to get more data to keep the plant up and running and safe," he said.
There are a variety of asset failure modes that the IntelliSAW Critical Asset Monitoring (CAM) can detect with temperature, partial discharge and humidity sensors. "One is thermal breakdown failure modes such as overload, corrosion or loose connections," said Short. "Another is insulation breakdown failures due to aging insulation and partial discharge, such as small electrical arcs at voids, or air pockets, within or on insulation surfaces. A third failure mode is air dielectric breakdown due to humidity contamination and moisture on the insulation surface resulting in long term insulation damage and metallic corrosion."
Some drawbacks with traditional monitoring are that it is only periodic, once or twice a year, and it requires a technician, which can be dangerous and expensive. "IntelliSAW continuous monitoring provides better safety in point of contact measurement, and it uses a wireless connection," said Short. "No maintenance is needed with the passive, long-life sensors used, and it is easy to install with a rugged design for medium voltage environments."
Critical asset monitoring
BASF installed the IntelliSAW devices in the assets to monitor a 2B/2B1 substation feeding power to its plant. "This switchgear and related hardware powered all the compressors in the facility—any failures would be costly," said Logue. "Components included temperature, partial discharge and humidity sensors mounted in and monitoring several locations including transformer primary and secondary, incoming breaker and incoming connection on each side of the substation."
A local reader wirelessly drives, or powers, the temperature and partial-discharge sensors and provides remote monitoring with network connection via Modbus RTU (RS-485). The continuous monitoring data is transferred through a third-party system to the DeltaV DCS where operators view the alarm notifications. Engineering also has access to detailed trends of the collected temperature, partial-discharge and humidity data.
"I now have a clear indication of the health of my switchgear equipment versus past failures where I only knew I had a failure when it blew up," said Logue. "I needed to know it was going bad six months prior. IntelliSAW continuous monitoring provides more electrical insight into the gear at the facility enabling predictive maintenance and helping eliminate reactive maintenance."
BASF was able to increase reliability, lower maintenance costs and avoid catastrophic failures due to unforeseen indicators. "With the solution installed and implemented, we detected an error in one of our readings," said Logue. "On a rainy day, the graph showed one of our humidity sensors had a high value of 60%. Later in that day, the sun came out and the humidity quickly dropped to 15%. The trend chart, compared to other humidity sensors that showed a flat trend, clearly suggested there was something going on. Based on that and historical data, it told us we had a water leak in one of our bus ducts. With this one measurement, the system paid for itself."