Economic Operation and Unit Commitment

What is the objective of the economic dispatch problem?

• The objective of economic dispatch problem is to maintain the operating cost of active power generation.

• The objective of economic dispatch problem is to maximize the operating cost of active power generation.

• The objective of economic dispatch problem is to reduce the operating cost of active power generation.

• The objective of economic dispatch problem is to minimize the operating cost of active power generation.

Economic distribution of loads between plants also know as _____________.

• unit commitment

• economic dispatch

• coordination equation

• Lagrange’s method

The rate of change of fuel cost with active power generation is called______________________.

• incremental fuel-cost

• participation rate

• incremental rate

• base point

Choose the statement or statements that describes the following case: "For economic dispatch that neglecting on both line losses and generation limits，"

• it is the most complicated economic dispatch problem.

• total generation is equal to the total demand.

• all the generator will share the load equally.

• when losses are neglected with no generator limits, for optimal dispatch all plants must operate at equal incremental fuel-cost.

• None of the above

For economic dispatch that neglecting line losses but including generation limits, what should be done if the power is outside the limit of a generator?

• The generator shall stop supplying immediately.

• The generator will remain as the participating generator in the optimization of dispatched power.

• The generator should be set to the limit, either at the minimum or maximum power

• The generator should always running at its rated power.

• The generator is no longer a participating generator in the optimization of dispatched power

What are the techniques for the solution of the unit commitment problem?

• Priority List Method

• Dynamic Programming Method

• Lagrange Relaxation Method

• Kuhn-Tucker Method

• ALL of the above

Define minimum up time.

• Once the unit is decommitted, there is a minimum time before it can be recommitted.

• Once the unit is decommitted, there is a maximum time before it can be recommitted.

• Once the unit is running, it should be turned off immediately.

• Once the unit is running, it should not be turned off immediately.

Which statement is not true about Unit Commitment?

• We can't simply commit enough unit to cover the maximum system load and leave them running all the time because it may be quite expensive to run too many generating units when the load is not large enough.

• Unit Commitment plans for the best set of units to be available to supply the predicted or forecasted load of the system over a future time period.

• The problem of finding the order in which the units are to be brought in and the order in which the units are to be shut down over a period of time, say one day, so the total operating cost involved on that day is maximum, is known as Unit Commitment Problem (UCP).

• Utility has to decide in advance which generators to commit and which generators to disconnect and for how long.

In power station practice "spinning reserve" is.........

• reserve generating capacity that is in operation but not in service

• reserve generating capacity that is connected to bus and ready to take the load

• reserve generating capacity that is available for service but not in operation

• capacity of the part of the plant that remains under maintenance.

What are the thermal unit constraints?

• Minimum up time

• Maximum down time

• Minimum down time

• Crew constraints