It has been said the measure of a utility’s grid resiliency is the extent of how well they have integrated their systems (smart meters, AMI communications, DMS, OMS, GIS, etc.).
One such application is integrating the Advanced (ADMS) or standard Distribution Management System (DMS) with the utility’s Geographical Information System (GIS) to create a common network model. This is seen as a best practice – having one common view of the network model across the enterprise prevents errors in judgments and reduces manual data entry. This article will discuss the challenges, recommendations and benefits of completing this integration.
Understanding the models
There are many differences between a static GIS geographical model and a dynamic DMS/ADMS operational model, as follows:
• The GIS is typically a graphical representation of the network that includes some connectivity aspects. This geographical network model is intended to be fairly static with regards to the state of the network.
• The DMS/ADMS network model is considered an operational model, meaning the state of the network is highly dynamic and represents the current state of the network. The applications within these systems require the full functionality of the GIS connectivity model plus the operational aspects of a network model.
• With regards to operational models, there are different types of network visualisation needed to manage a network efficiently:
– A geographical view of the network is used when associating network devices to land base references.
– An orthogonal or schematic view of the network is useful when performing network switching and allows operators to clearly see the scope of their switching actions without panning or zooming across a geographic network, leading to improvements in operator efficiencies.
• A further difference between the two models is that the operational model is required to be electrically phase-based to allow the ability to carry out single- or multi-phase operations.
Challenges of integrati on
When integrating GIS and DMS/ADMS systems, keeping network models synchronised presents multiple challenges. First, utilities must consider which system will receive network updates as related to field equipment additions, removals and/or changes. This decision defines the location of the “source of truth” (i.e., the location from which other models are synchronised). There are several ‘rules of thought’ in determining which system first receives this information:
• Option 1: Operational Model First. Network changes are populated to the operational model first and then the updates are sent, via an interface, to the graphical model. This can cause delays in updating the utility’s GIS, and the network data needed in the operational model is usually a subset of what the GIS needs.
• Option 2: Graphical Model First. Network updates are populated to the GIS graphical model first and then the updates are sent, via an interface, to the operational model. This can cause delays in updating the operational model.
• Option 3: Hybrid Approach. Different sets of network updates are populated to both models and updates are sent between them to align the data. This can cause more difficult model synchronisation.
• Option 4: Manual Maintenance. This can cause budgetary and efficiency concerns from duplication of effort to manually update each model and more difficult model synchronisation.
The ideal solution is option 2 above, updating the GIS model first and having those updates be passed as incremental updates to the DMS/ADMS model. This requires that field updates are entered into the GIS prior to energisation to keep the DMS/ADMS representative of the asconstructed network in the field. Secondly, the symbology of the two models must be considered. The static GIS model typically uses simplistic symbols, while the operational model requires symbols to be much more dynamic. These symbology differences are usually handled by a translation table (‘x’ in GIS = ‘y’ in DMS/ADMS). The third consideration is the unique identifier used in each model to specifically label the same object across each model. The unique identifier is the key reference point between the two databases when updating modified, added or deleted equipment.
The fourth consideration is how frequently models are updated and/or synchronised. Are they updated in real-time or periodically? Finally, utilities need to consider that their GIS systems are no longer just used to create aesthetically pleasing maps and that the need for data quality and connectivity will increase as two or more models become more tightly integrated. When systems are operated and maintained as independent models, the data quality focus for each model is specific to each system. As two or more models are integrated, data quality requirements change such that they impact all models when updates are made. Change management is essential as the demand for improved data quality places a completely new set of strict requirements and processes for making data changes to the GIS. When integrating two network models, business rules and processes will have to be changed. Not all of the data in one model is needed in the other. Understanding what is and is not needed in each model helps define the integration. When integrating two network models, business rules and processes must be changed.
With integration comes cost savings, through optimisation and efficiency, by minimising the amount of manual entry and duplication of network changes. This has the potential to reduce labor for manual data updates by up to 15 per cent. Data is entered once and shared with applications as needed. Utilities also have the confidence that everyone is looking at the same basic network, regardless of whether they are using the geospatial or operational model. This prevents errors in judgment and can improve reliability and, ultimately, the safety of employees. Additionally, each network model type (geospatial or operational) has an important role to play in the operations of any electric utility. Understanding the roles and limitations of each model helps to define their successful integration. It is worth the time to understand the impacts before trying to implement network model integration.