Demand response and dynamic line ratings for optimum power network reliability and ageing

Abstract

This study proposes a methodology to optimise the use of average demand loss of each load bus to enhance line ratings and modify load curves, by minimising demand loss and network ageing due to elevated conductor temperatures. The considered lines are connected to load buses, operated with dynamic line rating technology and have actual conductor physical properties. The simulation of line failures considers line loadings, whose values are based on utilizations of the average demand loss of load buses where the lines are connected, and the remaining service life of the conductor. Demand response in the form of peak-shaving and valley-filling is used to modify load demand curves, with the allowable peak load reduced based on utilizations of the remaining average demand loss. The average demand loss values are determined in the preliminary screening module of the proposed method. Various trade-offs between ageing and reliability of the network are solved based on the two-objective non-sorting genetic algorithm and fuzzy decision-making method in the execution module of the proposed method. Results have shown that the proposed method is cost-effective in that it strategically increase line ageing slightly to enhance system reliability, by as much as 71.9%, based on the equal emphasis of network ageing and reliability, when compared with the scenario that only prioritizes the protection of network ageing. Line ageing is also 68.2% lower on average across the entire spectrum of rating exceedance (1% to 25%) compared to the scenario that only prioritizes enhancement of network reliability.