IEEE Power & Energy Magazine - March/April 2017 - 52

Tool 1

Data

Automated
GIS Error
Correction

Network

Tool 2
Manual
GIS Error
Correction

Combined
GIS

Translation to
Electricals
Models
Creation and
Allocation of
Load and
Generation
Profiles

Meteorological

Socioeconomic

High Resolution,
Realistic Profiles
Tool 3
Detailed
Network
Studies
Tool 4
Visualization
of Results

figure 3. The integration of a GIS and network analysis in a single platform.

Integrating GISs and Network Analysis
A series of steps is needed to successfully integrate GISs
and distribution network analysis software (see Figure 3; the
tools will be explained in a later section). As each database
comes with different types of errors, from connectivity to
nonstandardized labeling and missing data, the first step is
to identify and, whenever possible, automatically correct
them. In general, engineering criteria is crucial to define
an acceptable level of accuracy when fixing these errors.
The next step is to combine the data from the corresponding multiple sources to have a single point for data retrieval
and thus facilitate exchanges. To create the electrical models
of the circuits, characterize the electricity demand, and produce the PV generation profiles, the University of Costa Rica
used the project data corresponding to the network assets and
customers (from DNOs), solar irradiance (from the meteorological office), and socioeconomic statistics (from the
latest national census). These databases were combined
using QGIS, one of the most popular free and open-source
tools for geographical systems and fully compatible with
commercial software used by the Costa Rican DNOs.
The translation from GISs to electrical models then takes
place and depends entirely on the adopted distribution network analysis software (each of them has its own way to define
electrical models). In this project, the free and open-source

Transformer Disconnected

MV Line
LV Line
Transformer
Load

Load Disconnected
LV Network Disconnected

figure 4. Typical errors in the GIS data.
52

ieee power & energy magazine

software OpenDSS, developed by the U.S.-based Electric
Power Research Institute, was used to model and analyze distribution networks; it was selected due to its flexibility and
the possibility of interacting with other software through the
component object model (COM) interface. Within this step,
a simple but important socioeconomic assessment is also
carried out, using the monthly energy consumption and geographical location of customers. This allows for the creation
of realistic load profiles and determining whether customers
would install rooftop PV systems (the larger the consumption,
the more likely the installation). The most adequate size for
the PV installation and the corresponding generation profile
can also be determined with this data. The last step in the integration of GISs and distribution network analysis software is
to make QGIS and OpenDSS talk to each other to carry out
specific network studies, which can range from snapshots to
daily and yearly power flows. The open-source programming
language Python was used to integrate QGIS and OpenDSS
as well as to drive their tasks. Thanks to the visualization of
GIS software, the corresponding results can then be presented
in a way that is intuitive and easy to understand for both technical and nontechnical people.

Practical Challenges
A key aspect in the integration of GIS data is to ensure that
all layers use the same projected coordinate system. It is also
critical that the GIS file formats are compatible among themselves; raster, vector grid, and geographic data files are common. However, the most challenging aspect is that the GISs
of DNOs and of other organizations are prone to human and
technical errors, which can be associated with the data itself
or the geographical position of objects. Data errors include
components with incorrect or missing attributes, the nonstandardized labeling of components, and the incorrect assignation of phases. For instance, in the GIS data of Costa Rican
DNOs, transformers were often found to have capacities equal
to 0 kVA while conductors of the same type were labeled differently. Three-phase segments were sometimes found to be
march/april 2017

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2017