Differentiated services QoS in smart grid communication networks

Abstract

In this paper, quality of service (QoS) requirements of smart grid and other utility applications carried over an integrated Internet Protocol (IP) network are analyzed. The delay allowances for the traffic flows may vary from 8 to 10 ms for teleprotection applications to up to one second or more for interval measurements from smart meters. Networking product and service implementation and practices for network quality of service will need to support the large variation in delay and priority requirements of these applications. The paper offers four main contributions: 1) A survey of QoS requirements for smart grid applications; 2) a proposal for active use of extended differentiated services code points (DSCPs) beyond those used for traffic classification in typical networks, services, and product implementations; 3) an analysis of using the strict priority queue to support multiple mission critical and other high priority applications; and 4) a special discussion on support for traffic generated by the teleprotection application and for its QoS requirements. © 2011 Alcatel-Lucent. implemented for actual classification of traffic. We then analyze overloading the strict priority queue with several mission critical applications with very low delay requirements. We show that to support the low delay requirements of smart grid mission critical applications when a strict priority queuing discipline is applied, it is necessary to provision large bandwidths at network aggregation points such as at a substation router. This requirement is validated with simulation results. Finally, we present the conclusions from our study.

Automating Electric Substations Using IEC 61850

“…Messages in the substation will have different priorities based on type and current operating conditions. Message priority can change as the current operating conditions change making it difficult to meet the timing requirements using the QoS features of Ethernet (Deshpande et al 2011). Deshpande et al (2011) propose a strict priority queue (SPQ) and provide a priority ordering of Smart Grid message types for the Differentiated Service Code Point (DSCP) feature in the IP header.…”

“…Message priority can change as the current operating conditions change making it difficult to meet the timing requirements using the QoS features of Ethernet (Deshpande et al 2011). Deshpande et al (2011) propose a strict priority queue (SPQ) and provide a priority ordering of Smart Grid message types for the Differentiated Service Code Point (DSCP) feature in the IP header. The SPQ feature provides a means to enable high priority messages to meet their delivery time requirement by preempting lower priority messages that have larger maximum allowable delays (Deshpande et al 2011).…”

Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection

“…With respect to the communication infrastructures, the employed technologies would traditionally consist of dedicated duplex channels between a generation utility and the transmission system operator for telemetry and telecontrol with additional voice/data channels over the public switched telephone network (PSTN) as a backup [3]. Within a smart grid environment, it is generally agreed that Internet Protocol (IP)-based communication networks are most likely to be able to support the connectivity and routing services that are required for smart grid applications [16,17]. It seems likely that the backbone for such an infrastructure will be the "utilities intranet": a data network which is common to the utilities but separate from the Internet, which is envisioned to allow for the eventual connection of all regional substations, equipment, and CCs throughout the grid [16,17].…”

“…Within a smart grid environment, it is generally agreed that Internet Protocol (IP)-based communication networks are most likely to be able to support the connectivity and routing services that are required for smart grid applications [16,17]. It seems likely that the backbone for such an infrastructure will be the "utilities intranet": a data network which is common to the utilities but separate from the Internet, which is envisioned to allow for the eventual connection of all regional substations, equipment, and CCs throughout the grid [16,17]. Standard best-effort IP links cannot provide the required QoS and network availability requirements to ensure low-latency, low-jitter communications over multiple hops [2,18].…”

“…To satisfy the varying range of QoS and routing requirements that smart grid traffic requires [19], differentiated services (DIFFSERV) traffic prioritization and enhanced multicast user datagram protocol (UDP) concepts offered by IP version 6 (IPv6) could be leveraged [16][17][18][19][20]. However, such end-to-end QoS management across multiple control areas is still some way off becoming a practical reality.…”