**3. DERs LNs standardizations brought by IEC 61850-7-420**

The global incoming booming of the DERs that need to be integrate to the energy grid, and the concept of bidirectional power flow raising challenges. Growing need for intra-substation to limit, overcome these challenges and integrate various DER in smart grid network. As a result, an extension for the IEC 61850 standard had been announced in 2009 as IEC 61850–7-420 to address these issues. IEC 61850–7-420 define and specify different LNs that support different aspect required and applicable for various DERs. The defined LNs are used to facilitate sharing the information signals among all participant nodes in the smart grid. This sharing information based utilizing the IEC 61850–7-420 in smart grid provide a great benefits in terms of reliability and availability.

From the above mentioned the consideration has been raised that the recently newer IEC 91850–7-420 standard will address the aspect that cover the modelling for different energy system DERs, since, within the first version IEC 61850 whole energy system aspects such as the services modeling, assigned system configuration language (SCL) and the mapping schemes are defined. These DERs information modeling defined by IEC 61850–7-420 standard involve not only for the local communication among the local DERs and the local management service systems, however, they may support the sharing information with the main grids operators or aggregators who manage the electrical grid operation. The defined DERs LNs based on IEC 61850–7-420 have been grouped into four groups upon their operation characteristic (node classes and common data classes (CDC)). These DERs LNs groups are logical nodes for DER management systems, logical nodes for DER generation systems, logical nodes for specific types of DER and logical nodes for auxiliary systems. These defined DERs LNs represents all the DERs operation aspects parameters such as for instance, connecting status, availability status, economic dispatch parameters, start/stop time, operating mode etc. however, in this paper based on the defined Islanding detection scenario, number of the IEC 61850–7-420 DER LNs have been selected in which are the DPST and the DRCS LNs. The real-time ECPs status and measurements is presented by DPST LN

(the ECPs are usually associated with each DER, load, lines Buses etc. that need to connect to the local power system, group of DERs that need to interconnect to the Utility energy system etc.). While, single DER or number of the same type of the DERs that may controlled within the same controller able to be presented by DRCS LN.

## **4. IEC 61850–90-x**

IEC 61850 is extended for inter-substations and has been accepted wildly from the both point views vendors and Utilities. Wide area application in smart grid based on state-of-the-art communication technologies are highly integrated in to the Automation systems. Therefore, IEC 61850 standard had been extended to cover these issues in series of IEC/TR 61850–90-x standard.

IEC/TR 61850–90-1:2010 specifies the inter-SASs communication that allows sharing real-time data among various power system nodes over different communication protocols and networks. While using all the previous comprehensive issues that covered within the first version of the IEC 61850 standard. Moreover, IEC/TR 61850–90-1 defines interfaces (IF2, IF11) to exchange data between substations upon protection, automation and control distributed functions.

IEC 61850–90-2 report considering the communication between the substations and the control centers which is under preparation.

IEC 61850–90-3:2013 communication networks and systems for power utility automation is considered by means of IEC 61850 for condition monitoring diagnosis and analysis.

IEC/TR 61850–90-4:2013 considering the local area network based SAS as well as provides the engineering guide line for communication and the limited requirements of IEC 61850.

IEC/TR 61850–90-5:2012 considering the wide area network based monitoring protection and control (WAMPAC), as well as provides the ability to sharing digital data (digital status, synchronous phasor measurements) among different energy system nodes. IEEE C37.118 is defined the synchronous phasor measurements data packet and its content, while the exchanging concept is complaint with the IEC 61850 definitions.

IEC 61850–90-5 supports the synchro-phasors real-time exchange of measurements technical requirements that had been defined within the IEEE C37.118 standard by implementing the previously defined IEC 61850 protocols (GOOSE, SV). While, IEC 61850–90-5, R-GOOSE routable GOOSE and R-SV routable SV, new routable mechanism through the new routable control block for the GOOSE and SV is defined. These R-GOOSE and R-SV data are mapped along with the control blocks that encapsulated in a session protocol data unit (SPDU). This SPDU might include number of data sets that contain deferent information other than just the synchro-phasors measurements. At this point since the data is routed among power system unites that my located in to deferent communication networks, multicast UDP/IP protocols are used. Differential Service Control Protocol (DSCP) also used to improve the delivery priority The DSCP limits the probability of delivery packets lost upon the router congestion, by adding the priority tagging to the delivered packets. Consequently, ac-cording to the IEC 61850–90-5 specifications, Internet Group Management Protocol Version 3 (IGMPv3) provides the "source filtering" option by means of enabling the subscriber hosts to register on a router and assign which group they want to receive multicast traffic from. As a result, the router does not need to copy the stream and assigned it to all the

#### *Advanced Communication and Control Methods for Future Smart Grid DOI: http://dx.doi.org/10.5772/intechopen.96596*

available paths. However, based on the subscriber's defined table within the router it determines the appropriate dedicated paths in which that relax the communication network and improve the multicast delivery mechanism. Whereas, security aspects within IEC/TR 61850–90-5 is considered based on the "perfect forward" by means of exchanging the predefined encrypted key between the publisher and the subscriber. The publisher host will announced beforehand about the next key to the subscriber host as well as the subscriber needs to detect the synchronization status with the current key.

IEC 61850–90-12 2015, considers the inter substation communications upon the existing standards and protocols for the WAN communication [11], as well as the definitions, guidelines and recommendations. It, defined the inter substations and the substation-to-control center, as well as specified different issues related to these links such as energy system topology, redundancy, jitter and QoS, in order to facilitates understanding the state-of-the-art technologies, and integrating of different selected components through the conduct testing.
