Reserve provision from fixed speed PHS
Fixed speed PHS can only pump at one level but can provide the total load as reserve (for some categories) by stopping pumping. A constraint (q_minCons) has been added to branch ReserveCapacitySharingPHS which allows the min load to be set to 0 so full reserve provision is allowed. The constraint ensures that the load is set to max (or defined % of max) when pumping. Has been tested on Irish system and seems to work as intended but constraint could probably be improved.