The evaluation of available transfer capability (ATC) is significant as it provides valuable information regarding the remaining transfer capability, after meeting existing commitments, for the system operators and market participants in a deregulated electricity market. The penetration of wind power generation is increasing significantly in modern power systems. Wind power generation is highly intermittent and uncertain. In literature, ATC is calculated with uncertainty in wind power generation using probabilistic density functions (PDFs). However, the PDFs of wind power generation are not always easily available. Range arithmetic is an efficient way of representing an uncertain variable without the need of PDF of that particular variable. Relative distance measure (RDM) arithmetic is one of such range arithmetic methods. In this paper, uncertainty in wind power generation is modelled using relative distance measure arithmetic. The optimization problem for finding ATC range with uncertainty is posed as two continuous linear programming problems (LPPs) in RDM arithmetic. As LPP is a convex inherently, the proposed RDM-arithmetic based ATC calculation method guarantees a global optimal solution. The proposed RDM-arithmetic method is tested on IEEE 30-Bus and IEEE 118-Bus systems. The simulation results are compared with Monte Carlo simulation (MCS) based ATC and interval arithmetic-based ATC. It is observed from the simulation results that MCS underestimates ATC bounds and interval arithmetic overestimates. It is also observed that proposed RDM arithmetic-based ATC calculation method takes significantly less computational time as compared to MCS and interval arithmetic-based ATC calculation method.generation cost, linear programming problem (LPP), mixed integer linear programming (MILP) problem, relative distance measure (RDM) interval arithmetic, transfer capability, wind power generation, uncertainty List of Symbols and Abbreviations: F k , flow on line-k; N, numbers of buses; nG, number of generators; nW, number of wind farms; P di , power demand at bus-i; P' di , power demand at bus-i in evaluation of ATC; P gi , power generation at the generator-i; P' gi , power generation in evaluating ATC at the generator-i; P gi min , P gi max , minimum and maximum power generation at bus-i; w 1 ,w 2 , weights corresponding to objective functions; ATC, Available transfer capability; CBM, Capacity benefit margin; ETC, Existing transfer commitments; TRM, Transmission reliability margin; TTC, Total transfer capability.