Comprehensive long term network planning within AM/FM/GIS
The process requires participation of all the major role players and the results must conform to the
needs of the customers served. The process is practical and followed by many organisations or
individuals before major capital expenditure is incurred. Strategic planning is an essential
prerequisite to the success of any business. Businesses or economies that excel globally are
characterised by sound strategic planning on a continuous basis.
The strategic plan also serves as a basis for project planning. The availability of such a plan
simplifies project planning for all disciplines. It is however important to revise the strategic plan
on a regular basis in order to accomodate changing external influences to which future planning
must react and adapt. Both annual and medium term project planning is far simpler with a long
term strategic plan in place.
The flow diagram in Figure 1 depicts the main steps of the planning process. The process starts
with various supporting tasks that are performed to gather relevant planning data, determine
refurbishment needs and obtain strategic long term inputs regarding land use, demographic and
economic studies.
Figure 1: Network Planning Process
With relevant data and strategic inputs available the geographical load forecast is performed for the
complete electrical supply area. Both the load forecast and identified network refurbishment needs
are used as inputs to identify network development alternatives. These alternatives are evaluated
technically by performing load flow, fault level and reliability analyses. The technically sound
alternatives are evaluated financially before they are finally checked against the planning criteria.
The chosen alternative is documented as the preferred alternative that forms the strategic
development plan.
Integration Issues and Constraints
Historically the steps mentioned in the previous paragraph were performed separately.
Applications / databases were developed to support these activities. These applications were
mainly developed to operate as stand alone modules, quite often with closed databases, limiting the
interfacing and integration possibilities without major software redesigns.
What is needed is an integrating technology that can form a platform for customised functionality
development based on one data set. This technology must also cater to integration with existing
legacy systems.
Network planning utilising AM/FM/GIS
In order to integrate existing legacy systems and to open access to multiple data sets and complex
functionalities, most leading utilities throughout the world today implement Geo-spatial
Information Technology (AM/FM/GIS). By providing a realistic model of the "real world objects",
AM/FM/GIS offers an environment for the efficient support of day to day functions of planning,
constructing and maintaining a network. It combines "background" data such as simple vector or
raster maps with structured/topological "foreground" network elements. The system thus
computerises technical information and is designed to take the network through the planning stage up to the AS BUILT stage.
Utilising Legacy Systems
Many utilities have legacy systems in place that perform mission critical functions. It would be too
costly and risky to replace all these systems. As integrating technology, AM/FM/GIS is used to
pull these systems closer together.
The AM/FM/GIS system is designed with the holistic utility process in mind. Where existing
systems are in place, the AM/FM/GIS system interfaces with these systems. These interfaces are at
various levels of detail. Legacy systems with an open database are linked actively to the
AM/FM/GIS system. If possible, referential integrity between the two systems is applied.
In the realistic environment a substantial number of legacy systems have proprietary databases
with very limited interfacing possibilities. In such cases data exchange is done by means of a text
file. More often than not no data can be imported into these legacy systems. These "closed" legacy
systems are the first to be replaced by appropriate functionality within the AM/FM/GIS system.
This approach ensures increasing data integrity and less room for human error.
Integrating the Planning Functions
Anybody who has been involved in proper long term strategic planning knows that the process
depicted in Figure 1 is a substantial amount of work. Even with the help of tailor made applications
/ databases for a number of the process steps, a major effort is required to maintain data integrity
between the various databases.
The implementation of AM/FM/GIS addressed the above mentioned problem and in addition
created at least two other major benefits.
Integrating the planning functions into one data model ensures that changes in one area are
available to other applications.For instance, the load forecast is automatically available to any load
flow study, combined customer damage function or calculation of a load duration curve. This
means that the planning information that is needed is available - no need for export and import
routines.
