Bringing intelligence to the single line diagram
As industrial technologies continue to advance, two major branches have formed in the power monitoring and electrical substation world. On the one hand, advanced distribution management systems (ADMS) are driving innovations in many areas of the modern supervisory control and data acquisition (SCADA) system, changing everything from advanced trending, alarm management and dynamic reporting. On the other, the single line diagram (SLD), which is often considered a core component of a SCADA application for a power monitoring system, hasn’t changed very much over the years.
While ADMS brings higher reliability, security and resiliency to utilities; it is a complicated system requiring substantial amounts of money, resources and time. What about the project budgets that are too small for the high price of an ADMS system, or are only looking to benefit from a subset of its features? As we look into the technologies enabled by ADMS, we can gain insights on how a less encompassing SCADA application can provide key ADMS features to benefit smaller projects.
Defining the single line diagram
In electrical power management, a single line diagram (SLD) or one-line diagram is defined as a form of block diagram graphically depicting the paths for power flow between entities of the system. Elements on the diagram do not represent the physical size or location of the electrical equipment, but it is a common convention to organize the diagram with the same left-to-right, top-to-bottom sequence as the switchgear or other apparatus represented.
Key functionality of a single line diagram
To give the operator a simplified overview of the status of the power system, a key functionality of the SLD is the automatic line coloring (ALC). The ALC shows the current state of the lines, relays, breakers, generators, devices, etc., along with some basic information about the components.
This feature displays power monitoring data in various colors, allowing the operator to know at a glance what is powered/unpowered and what are the statuses of certain pieces in the switch gear to ensure smooth operations. After all, it is critical to understand what happens where in the grid, which switching actions can be set and if there are problems, if it’s a matter of quick reactions, and if an overview of the correct handling is a critical success factor etc.
Advances in ADMS systems
An ADMS is – according to Gartner IT Glossary – the software platform that supports the full suite of distribution management and optimization. It includes functions that automate outage restoration and optimize the performance of the distribution grid. ADMS functions being developed for electric utilities include fault location, isolation and restoration; volt/var optimization; conservation through voltage reduction; peak demand management; and support for microgrids and electric vehicles.
As we move towards the smart grid, having a better understanding of all components on a larger scale – such as distributed energy resources, energy storage and electric vehicles – and how they relate to the ever-delicate balance of supply and demand across the entire grid has become more important than ever.
Businesses have taken advantage of the new need for utilities to have greater grid visibility by creating products that function as an ADMS. This has led to the development of many new features, such as ways to better visualize data. With the advances also come steep increases in cost and complexity. For projects where an ADMS and the associated cost in infrastructure are beyond the budget, finding a more affordable SCADA system that provides the key features of an ADMS is becoming an attractive alternative.
Key features SCADA can take from ADMS
To push the SCADA technology further and make ADMS features accessible for more utilities, we can turn back to the SLD. What if we can leverage proven ADMS technologies in the SLD of a traditional SCADA system? Let’s look at the key features we can take from an ADMS.
Load flow calculation and state estimation
As the most visited screen in SCADA power monitoring, the SLD is widely used to document power flow and the electrical functionality of the substation. Today, many utilities are using the SLD as the staple of their SCADA applications and do not require the SLD to consider the line length or its relationship in the physical space.
The load flow calculation (LFC) can be used in smaller grids at a substation level to analyze the distribution of the electrical power by measuring the inputs and outputs. With the pre-switching calculation, the operator can acquire information about possible overloads after executing the control command. In addition, an N-1 calculation continuously check whether assets are running safely.
The LFC does not just calculate active power but also considers the amount of reactive power available. It can also calculate all available grid topologies such as star, ring, as well as meshed topologies.
If there is not enough measured data available for the LFC, larger grids can acquire the missing information through state estimation (SE).
Another integral part of an ADMS is the geographic information system (GIS). It defines and maintains more accurate, complete networks by mapping out the real-world locations of the lines and key components (e.g. substations, switchgears, bus bars). This way, the operator can monitor the status of energy devices, such as line length, impedance, power inputs and outputs, and locate the assets accurately from the control room.
Modern SCADA solutions now allow utilities to integrate the GIS into the SLD architecture without needing a full-blown ADMS package. With the built-in GIS module of the zenon Energy Edition, for instance, the user can create a SCADA screen featuring the ALC, Worldview and so forth, and add a second layer with mapping elements taken from satellite maps. The process data is then acquired from the SCADA and can be displayed online and offline.
zenon for an intelligent single line diagram
As innovations like the ADMS continue to surface, power utilities are increasingly looking to modernize the SLD with more intelligent features.
The zenon Energy Edition from COPA-DATA provides modern, comprehensive SCADA solutions that provide the SLD with essential ADMS functionalities, such as the load flow calculation, state estimation and GIS. With zenon, utilities can improve SCADA in a more accessible, affordable way to work with today’s infrastructure.
Over 30,000 energy and infrastructure projects worldwide trust zenon to design, operate, monitor, and optimize the processes. To learn more about how zenon can help achieve your project goals, continue to browse our solutions or contact us today