If a recloser controller is commissioned and under SCADA control, it expects to receive periodic polling and communication from the control server. These are either requests for data, analogues and state, or controls, telling the recloser to execute some action. Typically, poll rates are executed in the sub-minute range. If the recloser does not receive a poll from the master station in that time, it can be assumed that the communications have been interrupted. The recloser reboots its communications device, to try to re-establish the connection. This is applied as an optional function within an OSM recloser with RC control. This functionality is known as a “communications watchdog”, and it has been implemented in NOJA Power’s RC range of controllers for many years. Whilst it is a simple implementation, the communications equipment reset is very useful, particularly for networks using IP based cellular communications.
Contact Nancy Holdsworth, Noja Power Switchgear, email@example.com
Source: EE plublishers