1 Abstract--Due to the increased interconnection of networks and the growth in the use ofnew power plants, fault current levels in power system continue to rise. One of the viable solutions for handling this issue is the use of fault current limiters (FCL) to reduce the short circuit current so that the existing Circuit Breakers (CB) can still operate without any upgrade. High- temperature superconducting fault current limiters (SFCL) are a widely accepted FCL. In this paper, a stochastic approach has been used for assessment of the transient recovery voltages (TRV) induced across CB poles of simple test line equipped with SFCL considering the uncertainties associated with system parameters and sensitivity analysis of these parameters. By this method, not only the expected value of the TRV can be calculated, but the probability distribution of it can also be determined. The simulations have been done in EMTP-RV environment. Index Terms--230kV transmission line, circuit breaker, EMTP-RV, fault current limiter, Monte Carlo method, Rate of Rise of Recovery Voltage (RRRV),short circuit level, superconducting, switching overvoltage, Transient Recovery Voltage (TRV). I. INTRODUCTION UE to the increased interconnection of networks and the growth in the use of distributed and renewable energy resourcesand new power plants, fault current levels in power system continue to rise; therefore it is necessary to upgrade existing substation equipment and especially circuit breakers (CB) with higher capability must be used.Differentapproach that can solve the problem of large fault currents is theuse of fault current limiters to reduce the short circuit currentso that the existingCBs can still operate without any upgrade. A fault current limiting device employing superconductors is commonly referred to as a superconducting fault current limiter (SFCL) is widely accepted as the preferable solution from both theeconomic and technical points of view.FCLs using High-temperature superconductors are a widely accepted solution and unlike Amin Mohseni is with High Voltage Institute of University of Tehran, North Kargar, Amirabad, High Voltage Lab(e- mail:a.mohseni@ece.ut.ac.ir). SaeedMohajerYami is with High Voltage Institute of University of Tehran,North Kargar, Amirabad, High Voltage Lab(e- mail:s.mohajer@ece.ut.ac.ir). Amir Abbas ShayeganiAkmal is with High Voltage Institute of University of Tehran as an assistant Professor, North Kargar, Amirabad, High Voltage Lab(e-mail: shayegani@ut.ac.ir). reactors or high-impedance transformers, it does not cause any power loss during normal operation. Application of FCLs requires evaluation of their performance and their effect on transient recovery voltage (TRV) and other transient phenomena across breaker poles like for example initial transient recovery voltage (ITRV) for breakers in networks with rated voltage above 100kV. ITRV is caused by the initial oscillation ofsmall amplitude due to reflections from the first major discontinuity along the busbar. In this paper, TRV has been focused and other transient phenomenon has been neglected because of their limited effects [1].Most of studies have been done in this field, were based on deterministic approaches [2], [3] in spite of several uncertainties in the mechanism of these FCLs. In most international standards related to CBs, the maximum TRV during a three-phase unearthed fault near the CB with multiplying factor of 1.3-1.5 is considered as the voltage that breaker must withstand [4]- [6] but other faults and different locations are more probable than what is considered in these standards. Worst case design is always an expensive choice and there may be another choice with optimum cost-benefit by obtaining a realistic appraisal of the expected TRV of CB with considering all events and uncertainties[7], [8]. The Monte Carlo method is a well-known method for handling uncertainties introduced by different parameters of problem; with using this technique and probability density function (PDF) of uncertain parameters, a realistic image of what is happening in practice, can be obtained. This method has been used for studying TRV in different uncertain environments [9]. In this paper, a Monte Carlo simulation approach has been used for assessment of the TRVs induced across CB poles of simple test line equipped with SFCL considering the uncertainties associated with system faults and their attendant protective switching sequences. By using this method, not only the expected value of the TRV can be calculated, but the probability distribution of it can also be determined. The simulations have been done in EMTP-RV environment. II. MODELING A. System under Study The test system used in this study is shown in Fig. 1,a 230 kV voltage source is connected to an infinite bus through transmission line with 300km length. A SFCL is implemented after CB. Sensitivity Analysis and Stochastic Approach in Study of Transient Recovery Voltage with Presence of Superconducting FCL A. Mohseni, S. MohajerYami, and A.A.ShayeganiAkmal D