Testing Protection IED In IEC 61850 Based Substation Automation Systems

Data models for substation equipment are also defined by IEC61850, the international standard for communication networks and systems for power utility automation. Additionally, a common, vendor-independent configuration concept is outlined in the standard.

The System Configuration Language (SCL) is the standardized format for machine-readable configuration data used in this procedure. In this article, we would like to provide you with all information regarding IED communication Testing.

• Architecture of Substation Automation

The Substation Automation System (SAS) architecture is hierarchical, with three typical levels for communication and application functions as defined by IEC 61850. Human Machine Interface (HMI), station computers, and Gateway (GW) are all part of the Station Level. The functions associated with this level communicate via a specialized network known as the Station Bus.

Traditional hard wires that carry binary information between IEDs are being replaced by some station-level functions. Additional functions serve as an interface between the station HMI and SCADA and SAS.

• Testing Protection IED In IEC 61850 Based Substation Automation Systems

When testing a Protection, Automation, and Control (PAC) system, established procedures include testing the protection element settings of IEDs and protection schemes. This is done in IEC 61850-based substation automation systems. Standardized and automated protection testing procedures can be supported by tools and methods. Relay types and schemes can be the subject of test plans that can be used in multiple project phases, such as Factory Acceptance Tests (FAT), commissioning, Site Acceptance Tests (SAT), and maintenance.

On the other hand, most of the time, manual testing is done on the Substation Automation System (SAS), which has a lot of automation, control, and SCADA features. While taking a gander at the time spent during charging, for instance, testing the robotization and correspondence framework is right now additional tedious than testing the security capabilities.

Testing communication, interlocking logic, and the correct operation of all signals transmitted to SCADA systems has significantly increased as automation systems have become increasingly complex. As part of the FAT and SAT, all connection interfaces between IEDs and primary equipment in substations must be checked. For hardwired interfaces, for instance, this is typically carried out one at a time in a manual procedure known as "green marking" all interfaces on printed wiring and functional diagrams.

When testing a Protection, Automation, and Control (PAC) system, well-established procedures include testing the settings of IEDs' protection elements and protection schemes. Standardized and automated protection testing procedures can be supported by tools and methods. Relay types and schemes can be the subject of test plans that can be used in multiple project phases, such as Factory Acceptance Tests (FAT), commissioning, Site Acceptance Tests (SAT), and maintenance.

On the other hand, most of the time, manual testing is done on the Substation Automation System (SAS), which has a lot of automation, control, and SCADA features. When looking at the amount of time required for commissioning, for instance, the testing of the automation and communication system currently consumes more time than the testing of the protection functions.

The efforts to test communication, interlocking logic, and automation systems have become increasingly complex. As part of the FAT and SAT, all connection interfaces between IEDs and primary equipment in substations must be checked. For hardwired interfaces, for instance, this is typically carried out one at a time in a manual procedure known as "green marking" all interfaces on printed wiring and functional diagrams.

A number of skilled control and SCADA engineers are involved in this process, which typically takes several weeks for a typical substation and should be completed during FAT prior to delivery and installation on site.

For system testing in the factory, the following hardware, software, and technical skills will be available:

• In an ideal scenario, the entire SAS, including all of the bay IEDs, networking equipment, gateways, HMIs, etc.
• A switchgear simulator hardwired to the IEDs (can be anything from simple switches and LED indicators to sophisticated PLC-based simulators); 
• A control center simulator that supports the used SCADA protocol (such as IEC 60870-5-104, DNP3); 
• Network testing tools and IED-specific maintenance tools; 
• Thorough knowledge of the implemented vendor products, the IEC 61850 standard, and Ethernet networks in general; 
• Well-prepared test plans and documentation (Signal spreadsheet, interlock In such instances, testing must only be carried out on-site, resulting in additional effort and expense.

Bugs and errors in the device's parameters, and occasionally its firmware, are discovered and fixed during the testing process. However, at the very least, a retest of the relevant function and, ideally, a retest of the entire system is required for each firmware version update and device setting change. If manual testing is used, this procedure is inefficient. As a result, a new strategy for more automated and effective system testing is crucial.

Based on the SCL idea in the IEC 61850 standard, such a solution is currently available.

• Testing RTU/Gateway and Local HMI Configuration 

Gateways, RTUs, and local HMIs typically use Reports and GOOSE to communicate with nearly all IEDs in the system. Each substation typically requires several thousand signals to be tested. By stimulating the signal in the switchyard, at least the most critical signals are tested point-to-point during commissioning. StationScout can simulate all other signals.

StationScout allows for the creation of a test plan that quickly verifies whether the RTU and gateways are correctly configured by simulating all of the substation's IEDs and signals. 

Conclusion

The SAS system's communication, automation, control, and SCADA components were tested using a novel test strategy based on the SCD file's information. Previously time-consuming test and documentation procedures can now be automated with test plans.