**6. Data object modeling based on IEC 61850–7-420 LNs**

Data object modeling based IEC 61850–7-420 LNs need to be virtualized. **Figure 1** illustrate the round trip GOOSE messages between the publishersubscriber-publisher which are modeled and need to be tested in real-time running in Opal-rt simulator. The round trip test setup consists from different IEDs. IEDs are configured to subscribe to the Opal real-time GOOSE messages and published back to the real-time simulator another GOOSE messages. Distributed IEDs are scattered over the communication system network through different distributed data points. These distributed IEDs are used for monitoring, control and protection function purposes.

LNs DPST and DRCS are selected to present the ECPs status and the DERs operation status respectively. LoM protection function based on its operation need to gather the information signals from the deined above LNs. LNs data structure is illustrated in **Figure 3** in which that listed and structured in tree manner down to data objects.

LoM protection function based on its operation, data object DPST.ECPConn included in to the DPST LN hierarchy is modeled for reflecting and indicating the ECP connection status. If the status of the data object DPST.ECPConn is "True" it indicates that DER is connected to the electrical grid through the ECP, and if it is "False" it indicate that the DER is not connected to the electrical grid through the ECP.

**Figure 3.** *Native IEC 61850 IED including the DPST and DRCS IEC 61850–7-420 LNs.*

DRCS LN is include the DRCS.ECPConn and DRCS.ModOnConn data objects from the list of data objects defined in to the standard. DRCS.ECPConn data object present the electrically connected status of the ECP of the DER. Therefore, if the status of this data object is "True" the DER is connected to the electrical grid through a specific ECP, and vice versa. DRCS.ModOnConn data object present the status of the DER. If it is "True" it indicate that the DER is in operation mode "ON" and electrically connected. Whereas if it set "False" it indicate that the DER is electrically connected and not in the operation mode.

Opal real-time simulator is configured as un IED that include LNs DPST and DRCS LNs data objects in its ICD file. According to this ICD file Opal real-time simulator has the ability to publish GOOSE message over the communication system network. Different IEDs are configured to subscribe to the Opal real-time simulator GOOSE message based LoM protection function. Control decision status can be extracted from subscribing to the Opal real-time simulator GOOSE message.
