25-04-2012, 11:38 AM
Security Constrained Unit Commitment
SECUCArtCohenABB.ppt (Size: 1.38 MB / Downloads: 54)
Security Constrained Unit Commitment
Optimizes the generator commitment and the energy, regulation and reserve dispatch.
Constraints include:
Demand
Regulation and reserve
Transmission constraints
– both intact network (base case) and cases with contingencies
Generator constraints
Also schedules phase angle regulators (PARs)
Typical Functions of Day-ahead SCUC
Provides forward energy and ancillary service schedules and associated market prices based on bid load
Schedules may be financially or physically binding
If financial, schedules can serve as a hedge against real-time prices
Provides commitment schedule that insures secure operations given the forecast load.
Commitment schedule is binding
Schedules produced are physically realizable – meet operational and network constraints
Consistent schedules and prices with both CRR and real-time.
Generation and Dispatchable Load Bids
Time-varying prices
Piecewise linear energy prices
No-load Price
Startup price
Time-varying bids
minimum/maximum amount
mustrun, fixed, unavailable
SCUC Solution Methodology
Combine two methods:
Network Constrained Unit Commitment program that:
schedules commitment and dispatch to minimize cost
considers network constraint equations that model effect of energy schedules on network flows
existing methods use Lagrangian relaxation or Mixed Integer Programming
Network Analysis program that
receives energy schedules,
simulates network flows for both intact network and for selected branch and generation outages (contingencies)
determines if there are any violations of branch/interface limits
generates constraint equations describing dispatch changes required to alleviate overloads and/or reschedules generation to meet constraints
uses Security Analysis or SC-OPF algorithms