microgrids are nowadays used to produce electric energy with more efficiency and advantage. however, the use of microgrids presents some challenges. one of the main problems of the microgrids widely used in electrical power systems is the control of voltage, frequency and load sharing balance among inverter- based distributed generators (dgs) in islanded mode. droop method performance degrades ...

The idea of a microgrid is created by utilizing more diverse ac or dc distributed generation (DG) sources along with an energy storage system (ESS) and loads. The most efficient and reliable selection of ac and dc microgrids is a hybrid ac/dc microgrid. The hybrid microgrid largely overcomes the shortcomings of standalone ac or dc microgrids. A bidirectional interlinking converter (BIC) is util...

Variation of frequency and voltage by load changes in a microgrid is a challenge in droop control method. Centralized restoration frequency or voltage in a microgrid requires communication link and therefore affects the advantage of decentralized droop control such as reliability, simplicity and inexpensiveness. This paper proposes a decentralized method that restores the frequency of a microgr...

This paper presents a cooperative control which is applied to the secondary control of a microgrid controlled via a multi-agent scheme. Balancing power that leads to voltage and frequency stability in a microgrid is essential. The voltage and frequency regulations are limiting within the specified limits and conveying them to their nominal values. Limiting and conveying the voltage and frequenc...

Measurements of partial discharges are commonly used to diagnose the insulation system in high voltage components. Traditionally a single fixed frequency of the applied voltage is used for such measurements as in the Phase Resolved Partial Discharge Analysis (PRPDA) technique. With the Variable Frequency Phase Resolved Partial Discharge Analysis (VF-PRPDA) technique the frequency of the applied...

voltage stability may be improved by various control functions. in this paper, it is shown that how high side voltage control (hivc) may be employed for this purpose. two test systems, namely a 22- bus and ieee u8-bus systems are used to demonstrate the proposed tuning strategy for hsvc control parameters.

Abbreviation of the action potential duration and/or effective refractory period (ERP) is thought to decrease the cycle length of reentrant arrhythmias. Verapamil, however, paradoxically converts ventricular fibrillation (VF) to ventricular tachycardia (VT), despite reducing the ERP. This mechanism remains unclear. We hypothesize that the size and the dynamics of the core of rotating waves, in ...