Power systems
Reza Karimi; Abbas Ketabi; Seyyed Mohammad Nobakhti
Abstract
The utilization of distributed generation (DG) sources in distribution systems has experienced significant growth due to their numerous advantages. Despite benefits such as voltage support and reduced losses, DG integration has introduced substantial challenges to distribution system protection, impairing ...
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The utilization of distributed generation (DG) sources in distribution systems has experienced significant growth due to their numerous advantages. Despite benefits such as voltage support and reduced losses, DG integration has introduced substantial challenges to distribution system protection, impairing the performance of conventional protection schemes. Variations in fault current levels, especially during islanding conditions, and bidirectional fault current flow are among the factors influencing the operation of traditional protection schemes. Under such conditions, directional overcurrent relays may not operate as intended. Moreover, coordinating multiple overcurrent relays is often challenging and can lead to increased operating times of protective relays. This paper proposes a directional comparison protection scheme for protecting lines and zones in active distribution systems based on the calculation of incremental active power transient energy. The proposed scheme is capable of detecting faults on microgrid lines at both low and medium voltage levels and is adaptable to changes in microgrid configuration. To prevent the directional protection scheme from operating during load switching transients, a differential protection scheme based on the calculation of transient energy of current signals is employed. The proposed methods offer the advantages of ease of calculation and high accuracy. An AC active distribution system incorporating inverter-based DG sources is implemented in the PSCAD-EMTDC software to simulate various fault types. The simulation results are then transferred to MATLAB for the implementation of the proposed algorithms.
Power systems
Amir Hossein Ataee-Kachoee; Hamed Hashemi Dezaki; Abbas Ketabi
Abstract
The deployment of microgrids (MGs) and smart grids to maximize the benefits from distributed generations (DGs) has increased. Although the MG framework and concept improve system flexibility and reliability, new challenges corresponding to the MG protection system appear compared to conventional passive ...
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The deployment of microgrids (MGs) and smart grids to maximize the benefits from distributed generations (DGs) has increased. Although the MG framework and concept improve system flexibility and reliability, new challenges corresponding to the MG protection system appear compared to conventional passive distribution networks. The adaptive protection schemes, which have been reported to consider various topologies in MG protection, need communication infrastructure. Also, the failure of telecommunication systems and cyber-attacks has drawn attention to unrelated protection schemes using local measurements, taking into account different topologies and related selectivity constraints. The literature shows a research gap in the development of local measurement-based protection schemes considering different operating modes and network configurations due to the unavailability of upstream substations, DGs, and other MGs sub-systems such as lines. This research attempts to fill this research gap by proposing a new protection scheme using dual setting directional overcurrent relays (DS-DOCRs) based on N-1 contingency topologies. The introduced method is applied to the distribution portion of the IEEE 30-bus test system. The Genetic Algorithm (GA) has been selected as the optimization algorithm, which is implemented in MATLAB, and the power system analyses are done in DIgSILENT. The test results show the advantages of the proposed method compared to the existing designs, only considering the limited operation modes. The test results indicate that mis-coordination for the N-1 contingency-based topologies does not appear using the proposed method.
