MONITORING OVERHEAD LINE SWITCHES WITH TOUCHLESS™ TECHNOLOGY

The Challenge

Utilities may have thousands of line switches in their service area with little or no visibility on their condition, status, or operation. Line switches are seen as the weakest link on grid, carrying heavy loads, including fault conditions, and functioning in severe weather on simple set of remotely operated, mechanical contacts.

Periodic inspections are time consuming and only provide a snapshot of the condition of the switches. These inspections don’t take into account environmental conditions or system load. Faulty switches can overheat and fail, causing outages and possible ignition of surrounding vegetation. Site inspections cost utilities time, travel and they may have to take planned outages to make sure the inspection can be done safely. It may take months for a utility to get through their whole coverage area and by the time they do, its time to start the process again. Manual inspections can miss problems, or they can crop up in between the inspection cycles. With the advancement of sensor and communications technology, utilities can economically install automated, continuous monitoring systems to improve safety, reduce costs due to manual inspections and increase the early detection of potential failures.

Background

Overheating at the contact points is the main cause of problems on line switches. Overheating can be caused by a number of issues:

Poor contact – switch contacts may not engage properly due to improperly installation or they become misaligned over time or due to movement of the structure the switch is mounted on. Without enough contact surface area for the current to flow through, the contact will heat up due to the I2R factor that could lead to arcing and pitting of the contact and eventual failure.
Operation of the switch under load will cause arcing and pitting of the contact point. Pitting of the contact point essential reduces the contact area and that leads to overheating, and increased arcing and pitting.
Carrying fault current beyond the switch rating will can cause the switch to overheat and could lead to arcing and pitting of the contacts.

Figure 2 – IM500 installation can be powered by solar power.

Thermal Monitoring of Critical Points – thermal monitoring of the contact and connection points on the switch can detect issues under all load and weather conditions.

Ease of Installation – due to the number of line switches that a utility may have the solution should be easy to install with minimal number of connections. Installation that could be done without an outage would be preferred. The sensor should be installed on existing infrastructure with wireless communication.

Network Security – the sensor, cloud dashboard and data storage must be secure and isolated from the utility enterprise network.

Data Integration – the data gathered from the sensor should integrate with the utility’s SCADA or APM system so it could be tied in with asset management, operations and maintenance applications.

The Solution

The IM500 Switch Module is an IoT sensor with onboard thermal and visual imagers and built-in wireless communications. An IM500 takes temperature readings on live systems and will detect overheating components in the electrical system including line switch contacts and connections. Due to its small size and low power requirement, the IM500 can be installed quickly in areas to provide optimal line of site monitoring.

Figure 3a and 3b –Thermal and visual snapshots from the IM500 show up close images of the line switch

Systems With Intelligence has developed IM500 mounting systems for a wide variety of applications. For the monitoring of line switches, the mounting system attaches to the structure above the body of the switch so it can be positioned to provide thermal and visual views of the connection points and contacts. The system is designed with high strength fiberglass and a series of adjustable clamps that allow easy positioning and quick installation.

Figure 4 - Comprehensive dashboard provides status, trending and visualization information

The IM500s are pre-programmed to take snapshots that give operators a visual and thermal view of the critical points on the switch. The thermal data is collected, stored and analyzed on a continuous basis. The connection to the SWI Cloud is authenticated and encrypted to ensure the safety and security of access to the device and data. The Systems With Intelligence dashboard provides a comprehensive view of the data providing graphs of the temperature points along with visual and thermal images. Alarms can be set in the dashboard, so operators are alerted instantly if temperatures exceed the pre-set thresholds. The data and alarms can be retrieved directly from the SWI Cloud, allowing the utility to trend the data and use it in a condition-based maintenance program.

The Solution

The IM500 allows utilities to perform remote, TouchlessTM Inspections, with 24/7 monitoring on sites and equipment that would otherwise be time consuming and costly to inspect. The IM500 provides visual and thermal imaging, providing continuous and up to date health information on multiple transformer subsystems. The IM500 installs easily with the Quick Mount, low voltage requirements and built-in communications. Temperature data is integrated with SCADA or APM systems for further analysis, trending and input to condition-based maintenance programs. Continuous thermal monitoring ultimately improves utility safety and reliability while reducing operating costs.

For more information contact us at [email protected], or visit our website at www.systemswithintelligence.com.