As the capacity of all-electric ships (AES) increases dramatically, the sudden changes in the system load may lead to serious problems, such as voltage fluctuations of the ship power grid, increased fuel consumption and environmental emissions. In order to reduce the effects of system load fluctuations on system efficiency, and to maintain the bus voltage, we propose a hybrid energy storage system (HESS) for use in AESs. The HESS consists of two elements: a battery for high energy density storage and a superconducting magnetic energy storage (SMES) for high power density storage. A dynamic droop control is used to control charge/discharge prioritisation. Manoeuvring and pulse loads are the main sources of the sudden changes in AESs. There are several types of pulse loads, including electric weapons. These types of loads need large amounts of energy and high electrical power, which makes the HESS a promising power source. Using Simulink/Matlab, we built a model of the AES power grid integrated with a SMES/battery to show its effectiveness in improving the quality of the power grid.

Resistive type fault current limiters (SFCLs) have attracted lots of attention from research interests and engineering applications, due to their self-triggering, fast and effective fault current limitation ability. Fast recovery of SFCL after quench is highly attractive, yet still remains challenge when recover with load compared to recovering without load. We investigated the dependence of recovery time of a helical SFCL coil on the ratio of prospective current over critical current I _pros /I _c . A multilayer simulation model was built in MATLAB/Simulink to investigate the electro-thermal behavior of SFCL coil during a fault and recovery period, and the model was validated by experimental results. Quench simulations were carried out under different I _pros /I _c , ranging from 15 to 119 and in different recovery conditions including recovery with load condition and recovery without load condition, while keeping the fault duration of 100 ms. We observed that the SFCL coil reached 85 K and 195 K at the time when the fault was cleared, in the quench tests with I _pros /I _c = 15 and 119, respectively. SFCL coil recovered without load in 0.5 s to 10 s, depending on the ratio of I _pros /I _c .

The increase in aircraft passengers and airfreight traffic has given rise to concerns about greenhouse gas emissions for traditional aircraft and the resulting damage to the environ-ment. This has led several companies and organizations, including NASA, to set goals to enhance aircraft efficiency as well as reduce fuel burn, pollution, and noise for commercial aircraft. The most notable electric aircraft (EA) concept is the N3-X, which was de-veloped by NASA to achieve environmental goals while maintain-ing the annual growth of the aviation industry. However, one of the main challenges that EA facing is their overall weight. This pa-per proposes and explores an improved power system architecture for use in EA based on the N3-X concept. The number of super-conducting magnetic energy storage (SMES) and fault current limiter (FCL) devices required can be reduced by utilizing multi-functional superconducting devices that combine the functionali-ties of both a SMES and a FCL, thus reducing the weight and cost of the EA by eliminating a complete device. The proposed control technique offers greater flexibility in determining the appropriate size of coils to function as a FCL, based on the fault type. The pro-posed EA power system architecture including the SMES-FCL de-vices is modelled in Simulink/Matlab to test the system perfor-mance under different failure scenarios.

Accurate power sharing in islanded microgrids (MGs) is essential to preserve the system stability and deliver the required load power. However, the distinct ratings of feeders result in disparate voltage drops and, therefore, varying output voltages from distributed generators (DGs). So, this work proposes a distributed adaptive virtual complex impedance to achieve accurate power sharing of loads between DG units with minimum control loops. The controller dynamically adjusts its parameters based on the system parameters, allowing it to adapt to various conditions. Unlike previous controllers, the proposed controller can work effectively with multiple connected DGs in the system. The designed approach accounts for complex components of the feeders’ impedances, with actual ratios between the complex components to enhance the system performance and the point of common coupling voltage. Based on that, the decoupling between the active and reactive power is achieved. The proposed controller’s effectiveness, including two and multiple DGs, is verified and compared to conventional control methods. For two DGs, the proposed controller proved its superiority over previous methods and proved its scalability in the DG system. The proposed controller is capable of achieving accurate reactive power sharing, reducing active power oscillations, enhancing the point of common coupling (PCC) voltage, synchronizing system currents, and minimizing circulating currents within the system. This is demonstrated through different scenarios. The first scenario is through a 2-DG system and comparing the results with conventional droop control and conventional virtual impedance. The second scenario involves statistically comparing the proposed controller with those in the literature, focusing on the controller percentage overshoot, response time, and PCC voltage level. The third scenario is conducted to prove the ability of the proposed controller to be extended for multiple connected DGs in the MG system.

As nations worldwide strive for carbon neutrality, Saudi Arabia has set ambitious targets to increase its renewable energy capacity, aiming for 50% of its electricity production to come from renewable sources by 2030. To accurately assess the economic viability of these photovoltaic (PV) projects, it is crucial to consider the levelized cost of energy (LCOE). In this study, we developed a comprehensive model incorporating PV panel annual degradation rate, initial system efficiency, and interest rates to provide a more precise LCOE calculation. The results demonstrate that PV panel annual degradation, initial system efficiency, and interest rate all significantly influence LCOE. In the most favorable scenario with a 0.5% degradation rate, 0.95 initial system efficiency, and a 0% interest rate, the LCOE was USD 0.0156/kWh. However, under the least favorable scenario with a 2.5% degradation rate, 0.75 initial system efficiency, and a 4% interest rate, the LCOE increased to USD 0.0317/kWh, representing a 103.2% increase. These findings underscore the importance of considering these factors when evaluating the economic viability of PV projects. By understanding their impact, investors and policymakers can make informed decisions regarding renewable energy investments and policies.

The annual growth rate of aircraft passengers is estimated to be 6.5%, and the CO₂ emissions from current large-scale aviation transportation technology will continue to rise dramatically. Both NASA and ACARE have set goals to enhance efficiency and reduce the fuel burn, pollution, and noise levels of commercial aircraft. However, such radical improvements require radical solutions. With the current traditional aircraft designs based on gas turbines or piston engines, these goals are infeasible. Small-scale aircraft have successfully proven emission reductions using energy storage systems, such as Alice aircraft. This paper involves an investigation of the possibility of using superconducting magnetic energy storage (SMES)/battery hybrid energy storage systems (HESSs) instead of generators as backup power sources to improve system efficiency and reduce emissions. Two different power system architectures of electric aircraft (EA) were compared in terms of reliability and stability in a one-generator failure scenario. As weight is crucial in EA designs, the weights of the two systems were compared, including the generators and energy storage systems. The two EA systems were built in Simulink/MATLAB to compare their reliability and stability. With the currently available technologies, based on the energy density of 250 Wh/kg for lithium-ion batteries and a power density of 8.8 kW/kg for generators, the use of the generators as backup sources proved more efficient than the use of HESS. The break-even point was observed at 750 Wh/kg for battery energy density. Any value more than the 750 Wh/kg energy density makes HESS lighter and more efficient than generators.