MiCOM Alstom P846 is an Open Line Detection relay providing fast detection for local and remote end openings.

A robust transmission system is critical for the transport of power from generating stations to demand centres. Today, with system loading much closer to design limits, the loss of a transmission corridor could unbalance the grid, risking power swings or even unwanted cascade tripping. The MiCOM Alstom P846 quickly detects open lines and initiates a safe, efficient defence plan. 

Open-line detection with no auxiliary contacts
MiCOM Alstom P846 detects local or remote end breakers open in 2 cycles. This open line detection does not rely on any auxiliary contact indications, or any teleprotection channel from the remote line end. It is therefore highly reliable. As a result, the utility can ensure automatic initiation of a defence plan if one or several open lines - loss of a power corridor – are detected.