A transaction schedule is a schedule
of incremental transfers between two subsystems over a series
of sequential time periods (e.g., MW transfers for each hour of
the day, peak MW transfer for each day of the week, etc.). However,
it is possible and often useful to define a transaction schedule,
which is a collection of incremental transfer quantities between
two subsystems that are not necessarily associated with time.
A composite transaction schedule, defined as a set of transaction
schedules of the same type, can be used to define a series of
load flow conditions upon which transfer analysis and other PSS™MUST
functions can be applied. For example, the daily cycle changes
in the power system conditions can be modeled by the transactions
representing power transfers within the same control areas, from
the generation to the load using load scaling methods.
PSS™MUST does not impose a
limitation on the sign of transactions; transactions can be negative.
Scheduling these transactions in Excel mode is equivalent to unscheduling
positive transactions.
The purpose of the transaction scheduling
subsystem in PSS™MUST is to provide a convenient way to
update load flow cases based on a user-specified set of transactions.
It is much simpler and more natural to update a load flow case
using transaction specifications than through individual bus and
generator data adjustments, using for example, PSS™E. Of
course, transaction scheduling updates the same buses and generators
in the load flow case, but it is automated through subsystem bus/generator
mapping according to participation factors defined in the subsystem
definition files.
After adjusting the load flow case
in accordance with scheduled transactions, all subsequent PSS™MUST
reports will be produced for the adjusted case. The user can also
save the adjustments associated with the scheduled transactions
in a load flow data file, which is useful for automatic load flow
case update.
There are several functions associated
with the transaction schedule worksheet that allow the user to
customize it. Headers may be added or deleted to reflect the type
of schedule desired. For example: Months or times of the day.
Transfers may be added or deleted. This allows the user to look
at the results of several variations of transactions using different
transfers. Transaction schedules may be saved and loaded. These
transaction schedules may then be used in other areas of PSS™MUST.
