Glossary Term: Settlement Period
Settlement Periods always refer to local time (whether this is GMT or BST). Note when the clocks go forward an hour, referred to as a ‘short’ day, there are only 46 settlement period for that day. Similarly, when the clocks go back an hour, referred to as a ‘long’ day, there are 50 settlement period for that day.
BSC defined definition
A period of 30 minutes beginning on the hour or the half-hour and in accordance with paragraph 4.3 of Annex X-2.