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.
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The Single Line Diagram is the most visited screen in SCADA to document power flow and the electrical functionality of the substation.
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.
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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.
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).
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Smaller grids can use the Load Flow Calculation to analyze the electrical power distribution. Large grids can acquire additional information through State Estimation.
GIS Editor
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.
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Modern SCADA solutions now allow utilities to integrate the GIS into the SLD architecture without needing a full-blown ADMS package.
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.
A newly released standard from the Institute of Electrical and Electronics Engineers (IEEE) has utilities thinking about their next-generation Smart Grid equipment. The IEEE 1547 standard has been updated and enforced in 7 states as of 2021. Starting in 2022, more states in the US will be forced to comply with the updated IEEE 1547 standard.
The IEEE 1547 standard establishes criteria and requirements for interconnection of distributed energy resources (DER) with electric power systems (EPS) and associated interfaces. It provides requirements relevant to the interconnection and interoperability performance, operation, testing, safety, maintenance and security.
