An electric utility recently had an issue with a 15 kV switch in which the water content in the oil exceeded the level
recommended by the manufacturer causing oil contamination and switch failure. The utility had performed the recommended preventative maintenance on the
switch; however, the oil sample and subsequent analysis had not revealed the issue. It is suspected that the moisture level increased significantly after
the most recent sample analysis. In order to prevent this in the future, PSStech was asked to develop a remote oil monitoring system.
Key Features of the Remote Monitor
PSStech designed and developed a minimally invasive, remote monitoring system that allowed for the monitoring of, and alarming on, moisture levels in the
oil. The monitoring system uses a moisture sensor that is installed in the oil level sight glass window port. PSStech designed and developed an adapter, as
shown, that allowed the moisture sensor to be installed in the oil level sight glass port while the sight glass remains intact. The monitoring system
continuously samples the moisture content in the oil and alarms when the %RH or PPM meets or exceeds thresholds set by the switch manufacturer. If an alarm
condition occurs, an e-mail is sent to the responsible party at the utility as well as PSStech engineers for evaluation.
The monitoring system uses cellular modem technology for alarming and data collection allowing the monitoring system to be installed at remote locations
or in equipment where communications do not exist. In addition to sending alarm e-mails, the data collected is sent in CSV format daily for tracking and
trending. The system incorporates an online, web-based dashboard making it convenient for power company engineers to view the status of the monitors and the
moisture level in the oil at any time.