Version
2.58
December
1999
Version
2.58
December
1999
GIPSY
Graphical
Integrated Planning System
GIPSY
is an Information Technology tool developed by Tractebel for analysis, planning
and graphical design of electric networks. It is based on a high-level
graphical interface associated with an object-oriented database. Different
modules for specialised calculation of network analysis can be added to this
standard platform.
This environment
has been designed to relieve users as much as possible from accessory,
repetitive and uninteresting tasks, enabling them to focus on the more critical
aspects of network planning.
The
graphical interface is used to create or enter different network elements
easily: branches, bus-bars, transformers, sub-stations, generation units,
loads, etc. The command for creating an element generates both the internal
representation of the object in the database and its graphical representation
on the screen. By clicking with the mouse on the representation of the object, one
can access its record in the database and consult all its associated
information.
The
central position and role of the database in the GIPSY environment is the
guarantee of the coherence of the data. What is stored in the database
corresponds exactly to what is displayed on the screen and of the data what
will be printed (WYSIWYG “What you see is what you get”).
The
database contains a detailed representation of each physical element in the
network. This mode of representation allows for optimum adaptation to most
planning applications, since the data can be processed at different aggregation
levels in line with the requirements of each application.
GIPSY
contains three different modules dedicated to calculations of power flows with
three different methods adapted to HV, MV and LV systems. The graphical
interface provides a clear view of the results, for example, highlighting
overloaded branches or nodes where the voltage is abnormal.
The
data required by these two models are prepared by the graphical interface which
transforms and aggregates the system physical representation into the data
needed by these models.
An essential particularity of GIPSY is
its capacity to generate both a semi-geographic view of the network and a block
diagram highlighting the functional aspects. This results in the possibility of
choosing, for each network element, either a synthetic representation, usually
in the form of an ordinary square, or a detailed representation.
By
applying this principle more generally, the “sub-network” concept allows
another scale or a different representation mode to be used for certain parts
of the network. For example, a functional, block diagram representation of the
internal topology of a complex sub-station can be combined with a
semi-geographic view of this sub-station in the context of the entire system.
By
making an optimum use of the multiple windows technique, users can work
simultaneously on an overall view of the system and in windows presenting certain
sub-networks in a more detailed manner, on a different scale and with an
appropriate plan background.
GIPSY
allows, for each network part, three different representations or views. The
first view, called fish-eye view, gives a general overview of the networks
under study. The second view, called mid-scale view, gives a geographical view
of the networks with a level of details corresponding typically to 1/25000
maps. The third view, called large-scale, gives a detailed geographical view of
the system, with a level of details corresponding to 1/2000 maps. The two last
views, with different backgrounds and line or cable paths, do not correspond to
a simple zooming operation.
The
program offers to the users a wide range of features, including lists of standard
objects which can be inserted in the scheme, automatic alignment and orthogonal
mode drawing, erase functions, as well as functions relative to associating
labels with the objects.
One
of the more novel characteristics of this program is its capacity to take into
consideration different variants (scenarios) of the system being studied and
their evolution in time over a determined time period. This means that not only
development options can be compared using a “what if” type mode, but also that
the future coherence of the studied options can be managed. Variants are also
called "worlds".
The
concept of “world” is of paramount importance for scenario management. Starting
from a root-world that represents the existing system and the information
common to all the possible scenarios (e.g. demand data and existing networks),
the user can create scenarios of development to be able to satisfy the
technical and supply quality requirements of the system during the study
period. So, “child”-worlds will be built, derived from the root-world or
existing child-worlds. If the system is modified in a specific world, this
modification will take place in all its “child” worlds, but not in its
“parents” worlds.
The
system loads are represented using load curves, either chronological or with a
load duration curve and load states. The loads can be introduced or modified
directly in the graphical interface or through the interface to spreadsheet
file. In this case, each load must be provided with its exact geographical
location. GPS (Global Positioning System) data can be used for that purpose.
Only such a detailed representation of the load behaviour allows an accurate
calculation of energy losses.
Detailed time consideration is a major
asset of the GIPSY tool. It is an essential feature for analysis and planning
requirements.
In the first place time representation is
used for the load curves in each demand node. Further, the representation of
the time allows the correct identification of each development strategy of a
system. Indeed, a development strategy extends over several years and it is the
sequence of investments that actually defines the strategy.
The
representation of several periods as the base time concept allows the check of
the coherency of the investment sequence. Indeed, for a specific year of the
planning period, the network elements are activated only if they are already
commissioned. Therefore, it is impossible to connect an element to any other
that would not be identified as already commissioned (see further, Coherency
checks).
Finally,
it is possible to display the networks at a given time, or to display all the
periods together, using different colours for investments made at different
periods (multi-periode mode : see figure below).
They
are 4 types of coherency checks inside the GIPSY software. Topological
coherency checks insure that a line is always connected to a node. Inside
large-scale (ex: 1/2500) maps, spatial coherency avoids the placing of two
network facilities exactly at the same place, or in single line diagrams, to
have two equipment with superimposed drawings. With the temporal check, the
database is protected against incoherency such as the connection of feeders to
a substation that do not (yet or anymore) exist at this time period.
Finally,
specific checks are linked to the hierarchical structure of the worlds. The
coherency check consists of verifying if an action taken in a world may lead to
incoherency in sub-worlds.
GIPSY
includes three integrated network analysis tools :
§
The load-flow for
MV networks (The FLAGS[1]
module)
A specific module targeted to
MV networks calculation is completely integrated in the software. Several operating
schemes can be memorised and analysed.
§
The load-flow for
HV networks (The Echo module)
Calculation of the active
energy and reactive energy circulation in a given network. The solution to this
problem consists in solving a set of non-linear equations; the method used is
the Newton-Raphson iterative method. Short circuit calculations are also made,
and the short circuit level at each node is published.
§
The load-flow
calculation for LV networks (The Atrebate module)
A completely different
calculation algorithm is implemented for the determination of the currents in
the LV networks.
The following relation
linking the peak power (P) and the energy (E) is the starting point of the
calculation algorithm:
The use of a special relation
is justified by the fact that the load factor, nearly constant along MV
networks (typical value of 0.4), varies considerably along the path of a LV
feeder (0.09 to 0.3).
Worlds can be used
for storing particular network calculation case. The concept of operation
scheme (i.e. mainly MV switch positions) allows the storage and the comparison
of different network configurations.
An
interface to and from .dxf
file is also provided, for map and plan background management purposes.
An
interface to and from .xls
(Excel) files is also provided to import/export alphanumeric data in the
database.
The GIPSY program has been developed
using Allegro CL, a dynamic object-oriented programming system from
Franz Inc. Allegro CL is based on an ANSI-standard language
(Common Lisp and CLOS) which meets all of the Gartner Group's
"must-have" and "should-have" criteria for object-oriented
languages. The underlying object oriented database system is ObjectStore from
Object Design Inc. It runs in the Windows NT environment and is
capable to store a large data set including hundred of thousands of network
elements.
GIPSY
has recently been used in several occasions:
§
In Kenya, under its old name of GRIP, to establish a large scale rural
electrification Master Plan. The medium voltage (MV) of the areas studied cover
a surface corresponding to some 300 A0 topographical maps (scale 1/50000); they
include more than 7,000 MV/LV sub-stations.
§
In the Ivory Coast, as part of the Rural Electrification Master Plan.
The impact of the development of rural system on the HV networks was also
analysed.
§
In Mauritius, in the context of a distribution networks (urban and
rural) Master Plan. The modules supplied in this case were the HV, MV and LV
calculation tools.
The
following figures illustrate different aspects or key feature of the Gipsy
software :
1. A view of the main display with the
mid-scale (1/25000), the large-scale (1/2500) and the corresponding fish-eye
views.
2. A view of the mid-scale window, with
network and background information.
3. A view of an operating scheme (one
colour per feeder) in the mid-scale map
fish-eye.
4. A view of abnormal voltage drops in red,
in the mid-scale map fish-eye.
5. A view of load-flow results (operation
scheme and overloads) in the mid-scale window.
6. An example of sub-network.
7. An example of the multi-period mode :
existing networks are represented in black, network at different time periods
are represented with coloured dotted lines.
