The per-unit-length capacitance of sector-shaped cables has been shown to remain relatively constant when operating in power system frequencies (up to 1MHz) making it possible to approximate it using closed-form expressions with reasonable accuracy. Numerical evaluation of frequency dependent resistance R and inductance L parameters of these types of cables remains computationally expensive. In this paper, the method-of-moment (MoM) discretization of the proximity- and skin-effect- aware formulation known as the surface-volume- surface electric field integral equation (SVS-EFIE) is optimized and applied for extracting the R and L parameters of circular and sector-shaped cables. While the proposed method guarantees to provide reliable data by iteratively achieving a desired accuracy, it also increases the efficiency of the MoM significantly. This makes the proposed method a suitable candidate for electromagnetic transient programs where rapid and accurate computation of the electrical parameters of sector-shaped cables is required.