Optimization
amirreza yari; Mahmoud Reza Shakarami; farhad namdari; Hassan Moradi CheshmehBeigi
Abstract
Nowadays, the power distribution companies are working in a competitive atmosphere. Therefore, a major goal for electricity distribution managers is to provide the electrical energy with high reliability level with considering the economic issues.The Reliability- centered maintenance (RCM) is an efficient ...
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Nowadays, the power distribution companies are working in a competitive atmosphere. Therefore, a major goal for electricity distribution managers is to provide the electrical energy with high reliability level with considering the economic issues.The Reliability- centered maintenance (RCM) is an efficient way of realizing this aim and improving the network maintenance processes. This approach is an operative step to improve the reliability of critical equipment and overall system performance which may reduce the costs of utilities.This paper, by using RCM provides a practical model for maintenance scheduling by considering the economic risk function and the budget restriction based on the cost of preventive maintenance (PM) and value of lost load (VOLL). In this method, PM schedules are proposed based on failure causes of different network elements. Studied elements include overhead lines, underground cables and power switches (circuit breaker (CB), manual and remote control switches (RCSs)). Failure cause and average repair time of each element is determined through data mining in geographical information system (GIS) and ENOX. For more realistic modeling and the consideration of the network loads’ uncertainties, the fuzzy triangular method is used. Due to the inconsistency between the problem’s goals, the non-dominated sorting genetic algorithm (NSGA II) is employed. Results show the effectiveness of the proposed method.
Power systems
Reza Sedaghati; Mahmoud Reza Shakarami
Abstract
A single-phase distributed generation (DG) sources embedded in three-phase microgrids develop with a fast-paced trend, it is important to make use of suitable power sharing strategies among multiple DGs and utilizing the power generation of these units to the full capacity. This paper presents an innovative ...
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A single-phase distributed generation (DG) sources embedded in three-phase microgrids develop with a fast-paced trend, it is important to make use of suitable power sharing strategies among multiple DGs and utilizing the power generation of these units to the full capacity. This paper presents an innovative sliding mode-based power control strategy for microgrids. The multi-bus microgrid consists of three-phase DG units that are two photovoltaic (PV) array, and three single-phase DG units including PV, battery and fuel cell (FC). The dynamic modeling of all DGs is based on voltage source inverter (VSI). One of the three-phase DGs is responsible for frequency and voltage control, and the other one for current control. The single-phase DGs are controlled based on the three-phase DGs. Finally, the voltage and power control operations are implemented in a per-unit system. The proposed control strategy has a fast response and the ability to trace a reference signal with a low steady-state error compared with the PI controller; moreover, it provides the accurate active and reactive power sharing among energy units under various loading and fault conditions along with robustness against the microgrid parameters. Additionally, the ability to maintain the dc-link voltage and frequency constant is another feature of this controller.