Vulnerability assessment approach for real-time and regional monitoring of backup protections: Minimising number of GPS-based distance relays

Abstract

Presenting an accurate and cost-effective solution to tackle static load encroachment issues in backup protection of transmission networks stand as a challenging task. Therefore, this study aims at devising a new backup protection scheme via GPS-based distance relays (GBDRs) against this issue. In this scheme, each GBDR calculates the vulnerability index locally, which helps to find out the vulnerable situation. When these indices exceeded their threshold, the protection centre is allowed for real-time monitoring in the corresponding area. In this regard, after calculating superimposed components, they are sent to the protection centre for discriminating faults from stressed conditions. Deployment of GPS-based relay in each bus brings higher costs and entails sharing large amounts of data. Therefore, a new techno-economic approach helps for the optimal deployment of these relays. To this end, zone-3 in some buses are eliminated, and the rest are equipped with GBDRs while each line at least is protected by two existing zones-3. By doing so, the network is divided into different areas that are protected with the minimum number of these relays. Whereby, coupled with the vulnerability indices, minimising the number of GBDRs alleviates the exchanged data.