The high-availability seamless redundancy (HSR) protocol, a potential candidate for substation automation system (SAS) networks, provides duplicated frame copies of each sent frame, with zero fault-recovery time. This means that even in the case of node or link failure, the destination node will receive at least one copy of the sent frame. Consequently, there is no network operation down time. However, the forwarding process of the QuadBox node in HSR is not smart and relies solely on duplication and random forwarding of all received frames. Thus, if a unicast frame is sent in any closed-loop network, the frame copies will be spread through most of all the links in both directions until they reach the destination node, which inevitably results in significant, unnecessary network traffic. In this paper, we present an algorithm called the dual virtual paths (DVP) algorithm to solve such an HSR excessive traffic issue. The idea behind our DVP algorithm is to establish automatic DVP between each HSR node and all the other nodes in the network, except for the QuadBox node. These virtual paths will be used for DVP unicast traffic transmission, rather than using the standard HSR transmission process. Therefore, the DVP algorithm results in less traffic, because there is no duplication or random forwarding, contrary to standard HSR. For the sample networks selected in this paper, the DVP algorithm shows more than a 70% reduction in network traffic and about an 80% reduction in the discarded traffic compared to the standard HSR protocol.Energies 2014, 7 1793

Abstract-High-availability Seamless Redundancy (HSR) is an emerging standard that is suitable for mission-critical communication of IEC 61850 based Substation Automation System in smart grid, where the dependability is very important. This redundancy protocol provides zero recovery time by offering duplicated frames for separate physical paths, but it generates and circulates unnecessary traffic inside the network that will degrade the performance of the network and may cause the congestion, delay, or frame loss. To improve the HSR network performance, the main drawback of generating extra traffic should be considered and eliminated. This paper demonstrates comprehensive performance analysis of IEC 61850 based substation automation networks and applies the quick removing (QR) algorithm to improve the performance of the HSR network to overcome the major drawback. The performance analysis includes the HSR modules, i.e., Doubly Attached Node for HSR (DANH), Redundancy Box (RedBox), and Quadruple Box (QuadBox), and IEC 61850 services, i.e., Generic Object Oriented Substation Events (GOOSE), Sampled Measurement Values (SMV), and report service. Performance analysis was conducted to verify the timing constraints described in IEC 61850 as a reference for designing proper HSR network topology. The numerical results show that the frame loss, restricted in mission-critical network, occurs due to large amount of traffic volume, which is the main drawback of HSR. The QR algorithm improves the traffic performance of HSR by reducing the unnecessary traffic along with the decrease of packet loss significantly.

No abstract