###### Abstract
It brings the following benefits: decreased short-circuit current during faults at the DC side that significantly reduces stress on the converter equipment [25; 26];
* DC circuit breaker. It brings the following benefits: limited DC fault current can be interrupted by a circuit breaker [27; 28];
* Energy storage and battery banks in microgrids. They bring the following benefits: reduction in battery current during a fault and extended battery lifetime [29; 30]. The task of the SFCL is to limit the short-circuit current to a value that allows the power system equipment (e.g., breaker) to operate (PSP). The conditions for proper cooperation of the limiter and power system protection require appropriate coordination of settings to ensure adequate sensitivity and selectivity of protections [29; 30; 31; 32]. In order to make the correct selection of settings, it is necessary to know the parameters of the SFLC, in particular, the critical current and the so-called limited current, i.e., the current value in the resistive state after the time resulting from the protection activation time. The main issue (which should be analyzed) is, therefore, the stability of the parameters of superconducting tapes during operation (with repeated activation). If the SFLC parameters are changed during operation, it may adversely affect the operation of the power system protection, and this situation should be taken into account when selecting protection settings. The SFCL uses second-generation (HTS 2G) high-temperature superconducting tapes without a copper stabilizer [33]. There are few reports in the literature on the degradation of HTS tapes and changes in tape parameters resulting from the operation of HTS devices. In [34], it was shown that multiple thermal quenching of the first generation (1G) BSCCO/Ag HTS tapes intended for SMES leads to a drop in the critical current. In [35], the dependence of the change in the critical current value of 1G Bi-2223 and 2G YBCO tapes with a copper stabilizer resulted from heating them in a thermostatic chamber as a function of time was examined. In [36], the correlation between degradation and delamination of HTS tapes of the second generation (2G) with a stabilizer in the form of copper layers was investigated due to overcurrent impulses, which led to a change in the value of the critical current. However, these tapes are not intended for SFCL applications. During the transition of the HTS 2G tape from the superconductivity state with a current exceeding the critical current of the HTS tapes, rapid thermal and dynamic processes occur, which can cause microdamage to the tape structure, leading to the loss of its initial parameters. The course of such processes is influenced by the parameters of the tape in the resistive state and the method of cooling the tapes. The article presents the study of changes in the parameters of 2G HTS tapes type CF (intended for SFCL) caused by multiple transitions of HTS tapes from the superconducting state by test current impulses (corresponding to different values of the prospective short-circuit current). The changes in the value of the critical current of HTS tapes were examined. The values characterizing the HTS tapes in the process of limiting the short-circuit current were determined: the surge current, the minimum value of the limited current, and the voltage at the end of the test impulse, as well as the energy released in the HTS tapes during the operation of the current impulse. A safe range of voltage drops per unit length was established for the tested tapes, for which degradation of the tapes does not occur or is negligible. In addition, cross-sectional studies of superconducting tapes were carried out using atomic force microscopy (AFM) and optical microscopy (OM) techniques. The tests aimed to verify the morphological changes occurring in the tested tapes.