Abstract

The facility to save multiple setting groups (SGs) within digital overcurrent relays (OCRs) is to adapt the active setting of the relays to the current topology of the power network. However, the number of available SGs is very lower than the possible topologies of the network, so, this facility is usually applied to a few local changes in the network. This paper aims to extend the application to a complete set of topologies. A proper index is introduced and applied with k-means clustering technique to classify the topologies into some clusters, whose number is equal to the number of the SGs. Then for every topology cluster, the optimal settings are calculated and saved in the OCRs as a distinct SG to be activated by changing the topology to any member of the cluster. Applying this technique to OCRs of the IEEE 14-bus test network and a 63/20kV substation verifies its effectiveness on reserving coordination for all the topologies and reducing the relays time dial setting. Using available communication links, this technique can be implemented by making a computer network between substations of the power network without needing to interact with the control center.