Software
Available in PDF
GAP is a software dedicated to analysis and planning of hydro-thermal power generation systems. A stochastic production simulation model calculates the technical and economical results of several production scenarios for a medium to long-term study period. A user-friendly graphical interface and a powerful scenario manager allow the user to easily analyze several generation configurations and to determine the optimum system expansion plan.
Most data and results are represented in a graphical form to better interpret them. User interface is especially designed
to offer very simple, friendly and efficient analysis and planning
procedures.
Powerful 32 bits Windows capabilities, such as multi-tasking and threads have been used to build real multi-processing applications, allowing to make complex but extremely fast calculations.
GAP uses a database that can be of any ODBC compatible type (Access, Paradox, dBase, InterBase,...). However, all DB management and access tasks are controlled automatically and totally transparent to the user.
The study and scenario managers allow to easily create and maintain
data and results of several system scenarios (hypothesis, or
cases study), using a hierarchical scenario architecture and the "inheritance"
principle. Inheritance means that, if some data is not defined in
a scenario, its value equals the value defined in its parent scenario, making the management of data easy in studies concerning a large number of hypotheses.
This allows for a simple and easy definition of scenarios as required for studies involving various cases or alternatives.
The kernel of the GAP is a stochastic Production Simulation
programme designed to compute the yearly production cost and system
reliability of a power generation system. This calculation module
is called PROSIM.
The method is stochastic because it recognises the main random factors affecting the generation process. It uses direct calculations based on probability distributions to produce the expected values of the main variables of interest: the energy each unit produces, the operating cost, the reliability of the generation system, and marginal production costs.
Individual loading probabilities for each unit can also be obtained. The uncertainty on hydro generation capabilities (natural water inflows) and on the fuel costs is modelled by repeated runs of PROSIM and sensitivity analysis using study scenarios.
In the GAP software, there are 5 groups of input data:
For each group, the user will specify several alternative developments during the time of the study. A specific combination of these alternatives represents a Scenario. Generation expansion planning involves several alternative projections or cases for each data group leads to a particular Scenario.
GAP offers a powerful scenario manager which allows the user to easily create, maintain and organise the data and corresponding results of various expansion scenarios. Scenarios are organised in a hierarchical manner. The inheritance principle allows to distinguish easily for each scenario which data are different from its parent scenario.
Generation data define the power generation capabilities of thermal-, hydro- and pumping storage units. Typical data for these units are installation and decommissioning years, investment- and operating costs, generation capacity, reliability, fuel consumption, etc.
In the maintenance data section, the user determines for each generation unit the weeks when it will be unavailable due to planned maintenance. Several cases (alternatives) may be defined for each generating unit.
For each hydro unit , for each week of the study
period, its generating capacity, the 'must run' fraction of it,
and the generated energy will be defined. Several cases may be defined to reflect
various water inflow or hydro operation assumptions. Hydro data
is automatically shown in a graphic way which allows visual
plausibility check.
These data describe, for each fuel mentioned in the consumption data of the thermal units, the heat contents and the cost evolution in time. Fuel cost evolution is automatically shown in a graphic way which allows visual plausibility check.
The system load evolution is described in a very compact form. It
uses a yearly peak value, a yearly load shape of weekly peaks, and
weekly load shapes of daily peaks. Several alternatives can be defined
in various cases to be included in different expansion scenarios.
Load data evolution and profiles are automatically shown in a graphic
way which allows visual plausibility check.
The kernel of the GAP software is a stochastic Production Simulation programme called PROSIM. This programme uses the weekly system Load Duration Curve - obtained from the load data - to determine the most economical scheduling of thermal, hydro and pumping-storage units.
GAP main results are twofold: Economic results (investment and
operating costs) and Technical results (Loss-of-Load probability,
Expected Unsupplied Energy, Produced Energy; etc.). Both types of
results can be achieved at system level or for each generating unit
individually; for each year of the study period, and for the overall
period. They are presented in the form of columns of values which are selected
by the user. Corresponding reports can be previewed and printed.
In addition, weekly data resulting from PROSIM calculations may
be selected and shown graphically, and reports may be previewed
and printed.
Results of various expansion scenarios can be shown simultaneously in separate windows, allowing for easy comparison and selection of the most economic scenario.
Article in Adobe Acrobat format: gap_article-E.pdf.
Further reading: "Power Generation Operation & Control " (chapter 8) Allen J. Wood, Bruce F. Wollenberg (John Wiley & Sons, 1984).
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