Application of simulation feature and subscription monitoring in IEC 61850 Ed.2 for testing protecti

Session Title: Commissioning and testing procedures and tools (e.g. IEC 61850)

Simulation feature is an advanced technique introduced in IEC 61850 standard (Edition 2) to test Intelligent Electronic Devices (IEDs) by logical isolation, where the actual inputs to an IED are temporarily replaced by test (simulated) inputs. Using the simulation feature, an operational IED can be made to switch between simulated inputs and regular inputs via a control action, which is typically achieved through a MMS command from a remote client. A simulated data stream has an identical configuration to its counterpart (i.e. the regular data stream) in every aspect except for the simulation flag in its header information. This feature is supported in both GOOSE and SV communication protocols and offers a significant degree of convenience in testing commissioned IEDs, as it does not require any rearrangement of existing physical connections.  

Another powerful feature introduced in Edition 2 of the standard is subscription monitoring for GOOSE and SV streams respectively using dedicated Logical Node (LN) classes named LGOS (LN for GOOSE Subscription) and LSVS (LN for Sampled Value Subscription). This is a useful technique for diagnostics as it is not always possible to deduce the status of subscriptions by simply looking at the subscribed data values. In addition, the subscription monitoring also compliments the simulation feature by indicating if an IED is subscribing to regular data or simulated data.

When used together, the simulation and subscription monitoring features offer a robust and convenient means of testing IEDs. This paper presents an overview of each feature and their application in real-time, hardware-in-the-loop simulations. Implementation details of these techniques in a Digital Real-Time Simulator (DRTS) are also discussed. In addition, this paper presents a case study, where these features are applied in testing an advanced protection scheme involving multiple external IEDs using a DRTS. The work carried out in this work underlines the power of the simulation feature and subscription monitoring in testing IEDs as well as the advantages of widely supporting and using them in modern substation automation systems.