GIS/OMS project implemenation at peco energy, an exelon company
Landbase selection
A landbase is a mapping product that contains information regarding the geography of
a specific area. Information can include street names (and aliases), political
boundaries, and waterways. It may also include street range information for location by
address.
The decision to convert your existing landbase to a commercially available product is
unique to each organization. You need to be able to answer the following questions:
-
How many documents need to be converted?
- What accuracy does the application require?
- Are there plans to share information with external organizations (government
organizations)?
- What are the plans for incorporating GPS (global positioning system)
functionality?
At PECO Energy, we have over 80,000 documents that have a homegrown landbase
and grid system. The system does not match any of the commercially available
products. Since our primary focus is to the install a new outage management system,
we chose to convert the off-the-shelf product. The conversion ensures that we have a
seamless, geographically accurate, primary circuit map (2600 circuits, 3800 documents)
and that information is consistent among all of our documents. The other documents
include secondary maps and cable/conduit information. We do not have a need to
share our primary map information with any external organization.
GIS model development
A GIS is a repository of information. The final application dictates the information
gathered and stored. For example, if you are planning to manage assets with the
system, then information like manufacturer, date purchased, installed, etc. is necessary.
If you are planning to design from the system, then information like rating, voltage class,
interruption rating, phase, status, type (oil breaker vs. SF6), etc. is required.
To support the OMS, we needed a sparsely populated GIS database. We chose to
only model the primary equipment and the premise (house meter location). However,
you may need to capture additional equipment to support the selected items. As an
example, to install an aerial transformer, one needs information about the structure that
supports the transformer.
In designing the GIS (for OMS), one also needs a very good understanding of how your
particular system operates. The GIS application generally supports a breaker,
transformer and switch. You may have breakers that operate differently. At
PECO
Energy, we have a 34kV distribution system that feeds 4kV unit substations. A unit
substation is a transformer and rackable breaker integrated into one structure. Our GIS
model needed two types of breakers to distinguish between the unit substation and the
distribution substation. We also have a few breakers that we call line breakers. One
side of the breaker is circuit 1 and the other side is circuit 2.
PECO Energy extensively uses interposing transformers. These transformers step the
voltage from one distribution level to another. We configured our GIS model to handle
both types.
Fuses and elbows are switching devices. You may have different symbology or
different operating practices for each device. You need to ensure that the GIS model
can accommodate all of them. For example, PECO has a combination, terminal pole
symbol and a standard fuse symbol to identify a terminal pole fuse. We did not need to
create a special device for the terminal pole fuse. We did, however, need to make
changes to the standard product to cover switchgear and elbows.
When you make changes to the standard product, you need to ensure that you
document and thoroughly test the changes with converted data as well as new data
(placement rules). To support the OMS migration development, we chose to do our
testing of GIS in stages. The first test supported data and functionality required to
support data conversion and OMS development. The second test focused on
interfaces and changes to the program that did not impact data conversion.
