UOF Close Block Operation

UOF Close Blocking is only operationally effective when either UOF protection is enabled for the active protection group.

For an UOF element to apply a Close Block, all of the following must be true:

• Protection On

• UOF Protection Available

• Close Blocking Available

• UOF Close Blocking On

• The element is in a faulted state that is in pickup

• The element is enabled

An UOF element will remove its Close Block if:

• Protection is turned Off

• The element is disabled

• Close Blocking is Not Available

• The UOF Close Block is Off (for the active group)

• The element is Off

• The element is un-faulted that is not in a pickup state.

It is important to note that UOF Close Blocking differentiates between UOF. If Under Frequency is enabled but Over Frequency is Off, UOF Close Blocking will only block if an Under Frequency element pickup is active.