Line Switch Automation

Line switches manage the electric connection of the substation to the grid by physically connecting and disconnecting power lines. A primary application of line switches is to enable technicians to disconnect a substation from the transmission grid or disconnect distribution lines from the substation to allow safe maintenance and repair. Typically, throwing a line switch requires a technician to visit the site to manually open or close the circuit.

With a two-way network configured to communicate with line switches, utilities have the ability to monitor and control these distribution grid elements from their centralized locations without requiring the dispatch of a technician. With the addition of video monitoring, remote operators can also visually confirm the status of a line switch prior to working on a circuit. Distribution networking enhances the function of a line switch by:

• Remotely sense and report line switch position (open, closed)
• With video monitoring, visual confirm line switch position
• Remotely actuate/toggle switching

Communications to line switches do not require much bandwidth; however, if line switch operation is required for immediate disconnect or reconnect, they need always-on connectivity and low-latency communications across the distribution network in order to enhance grid reliability.

The SecureMesh WAN products provide an optimal solution for communication with line switches. SecureMesh WAN Connectors are cost-effective outdoor wireless devices that provide Ethernet connectivity, either for a direct Ethernet connection to the line switch’s communication port or for a serial (RS-232, RS-485) connection via a Ethernet-to-serial adapter, that enables communication via both legacy protocols (DNP3, Modbus) as well as TCP/IP. Each SecureMesh WAN Connector provides long-range links (up to 7.5 miles apart) to connect remote line switches with always-on wireless communications. In addition, every link is encrypted for security and communications can be partitioned into virtual private networks (VPNs) for additional security and traffic guarantees.

With the SecureMesh WAN providing distribution networking, the Smart Grid deployment can provide cost-effective communications to line switches and integrate into SCADA and distribution management systems (DMS). Extending a Smart Grid network to line switches results in efficient and safe technician dispatch, reduced outage time, improved grid reliability (i.e. lower SAIDI, MAIFI, CAIDI, SAIFI metrics), improved visibility into critical load information,  improved asset management, and lower operations and maintenance costs, which also results in improvements in customer satisfaction.