Performance Improvement for the HSR Ring Protocol with Traffic Control in Smart Grid

High-availability Seamless Redundancy (HSR) protocol is proposed to recover disconnection of network within a short time. An Intelligent Electronic Device (IED) within a ring topology transmits two identical frames to the destination IED through both of the ports. This means that even in the case of disconnection of network, there is no stoppage of network operations whatsoever. However, because two identical frames are circulated inside the network, HSR protocol has a problem that causes the unnecessary traffic. This problem will degrade the network performance and may cause network congestion or delays.In this paper, we propose improvement of ring topology-based HSR protocol traffic performance using a Traffic Control IED (TCIED). First, we select one of the IEDs within a ring topology as a TCIED. The TCIED has the function to keep information of all the IEDs through Supervision Ack frame. Also, If TCIED cannot be received identical data frame for a certain period of time after a data frame receiving, the TCIED transmits data frame to a destination IED. In an existing HSR protocol, all the IEDs transmit Supervision frame using multicast. However, in this paper, only a TCIED transmits Supervision frame, and general IEDs received Supervision frame transmit Supervision Ack frame to the TCIED. Also, Timer of the TCIED is occurred after a data frame receiving. If the TCIED cannot be received identical data frame before the timer expires, the TCIED transmits data frame to a destination IED. By using Traffic Control IED, the proposed algorithm will reduce the network traffic and retain HSR network’s availability. The performance evaluation shows that the proposed algorithm is better than an existing HSR algorithm.This work was supported by Basic Science Research Program through the National Research Foundation by Korea (NRF) funded by the Ministry of Education, Science and Technology (2012-0005507