In the depths of the SAS

StationScout makes Substation Automation Systems transparent.

What is the key focus of commissioning secondary technology?
Traditionally, it is testing the protection devices and the way that the entire system functions. Substation automation systems (SAS) are starting to be used in modern installations. When it comes to individual protection devices, they not only monitor important components and feeders in energy transmission, but they also communicate with one another. This communication is key when it comes to the
SAS functioning smoothly and predictably.

If you compare the effort that it takes to test the functionality of the protection system with what it takes to test the automation and control system, there is a significant difference, with the SAS losing by a long shot. This is due in large part to the increasing complexity of the structure and the signals being transmitted. The system requires these signals in order to function properly and communicate with the control center.

However, the IEC 61850 engineering process and the data available in the SCD (substation configuration description) files, open the door to new testing methods that make commissioning and factory acceptance tests faster and much more efficient.

This data forms the basis of a completely new approach that is embodied by OMICRONs testing system StationScout. It’s been developed specifically for this purpose and it dramatically simplifies and speeds up testing for automation and control technology in IEC 61850 automation systems and covers the whole lifecycle of a SAS.

The name speaks for itself because, like a scout, it goes into the depths of the SAS and explores all of the components and connections. By analysing the SCD file, the system independently identifies potential signals for testing. It also detects communication connections and IEC 61850 services that have been implemented. Afterwards, the results can be used by the tester to create testing plans for both
factory acceptance tests and commissioning tests.

The Smart Overview Package, released in 2018, enables signals to be tracked in the SAS, and detects any GOOSE publish or subscribe problems. It also allows interlocks to be tested manually and to simulate individual components or the whole SAS – a huge time saver when testing protocol gateway/RTU configurations.

Cyber-secure connection
StationScout comprises two components: the high-performance MBX1 hardware and the software that runs on it with all of the necessary tools. MBX is controlled via a Windows PC. The additional firewall integrated into the system separates the testing solution (MBX1 and laptop) from the substation network, thus ensuring cyber security.

Because the SAS operation is often organised into several networks at once, MBX1 comes with four Ethernet interfaces for connection and analysis.

Simple and comprehensive presentation
One of the main problems that surrounds testing components and communication in SAS are the complicated terms described in the IEC 61850 standard. StationScout detects the names and purposes of the respective elements in the data model. It then visualises them
with clear names and the corresponding connections in a graphic interface. These names can also be adapted, for example, to the respective national language.

This visualisation is performed with all of the available data in the SCD file. This includes all of the important data from the substation, such as the voltage level and the switchboard section. For this purpose, there is also an option for modelling in single-line diagrams, according to the standard. Because the majority of the current SCD files do not contain the information necessary for this, we have introduced the new ZeroLine presentation. This reproduces the respective status in real time. Navigation in a large SAS can be carried out in the same way that it is done in a cartographic system.

Intuitive signal tracing
Within an SAS, GOOSE messages are transmitted by multicast from their source to all of the recipients. If an error occurs during this communication exchange, the protection testers must follow the signal on its route through the SAS, which has previously been difficult and very time-consuming, even with copper cable networks. In systems with IEC 61850, manual signal tracing is no longer possible.

Therefore, StationScout visualises all of the connections, shows how the signals propagate through the SAS and shows where they go and where they don’t. In addition, special filters reduce the overall complexity by allowing the display to focus on the relevant elements and then displaying them in the intuitive “Smart Overview”. This also includes tracing messages and signals sent as GOOSE, which simplifies error corrections in the communication structure significantly.

Anything missing will be simulated
One of the key features of StationScout is its ability to simulate individual components through the entire SAS, which can take place at any time during project planning. This can begin as early as the design, specification and engineering phase, and the test plans created at this point are available for the entire life cycle of the SAS.

Real-time values can even be worked on and tested during the factory acceptance test (FAT), which can then be verified again
during commissioning. Using this feature speeds up the process considerably. All of this data then forms the basis of a quick and successful maintenance check, which also refers to these plans. In each of these steps, Station Scout can simulate any IEDs that are missing so that the entire testing process can run smoothly.

Commissioning license accelerates testing
With the functionalities described above, StationScout already offers huge advantages for increasing the effectiveness of SAS testing in accordance with IEC 61850. The new Commissioning package greatly simplifies the testing of a SAS. It automatically identifies the signals used within the SAS or communicated to the control center and allows signal lists to be imported from spreadsheets. The tester can create a watch list to filter individual signals to focus on the information relevant for a test. This makes troubleshooting communication and logic errors much easier and faster.

Each test case can be described step by step to avoid accidental damage to equipment during the test. In addition, for each test case it can be defined in advance which signals are required for assessing the result. For example, for the interlocking of a load switch, the switch must not be operated under load and the corresponding signals must therefore be traced.

Once created, test plans and test results can be printed and duplicated for reuse in other feeders. Therefore, any tests that have already been carried out can be repeated quickly and easily. This saves a lot of time, especially when tests have to be performed frequently as a result of the numerous security patches and firmware updates being released.

StationScout also facilitates the documentation of all tests that were carried out, including test cases and test steps, and provides new overviews for this purpose. It works with any network topology and is the ideal tool for testing HMI and SCADA.

Authors:
Thomas Schossig, Product Manager Business Development Power
Utility Communication at OMICRON, Austria.

Mohit Kumar, Application Specialist, Power Utility Communication
at OMICRON, India. Email Id: mohit.kumar@omicronenergy.com

Factbox:
Advantages
• Guarantees cyber-secure connection to the substation automation system
• Clear live overview of signal flows in the IEC 61850 system
• Quicker rectification of communication and logic errors
• Simulation of missing components or the whole SAS
• Connection to multiple substation networks
• Re-use of test plans for recommissioning and following security patches (Commissioning Package, 2019)