Stochastic Modeling of Electric Car Charging Station for a Taxi Fleet

The uninterrupted operation of electric cars requires an adequate number of chargers installed in charging stations. The incoming requests determine the required number of chargers in the station, so it is of utmost importance to have practicable car motion models for planning purposes.In this paper a stochastic model is proposed to simulate the behavior of a taxi fleet consisting 100 identical cars. Car usage characteristics were extracted from real life measurement data and then synthetic driving cycles were generated by Monte Carlo simulation. The state of charge of every car can be monitored and the number of cars that have to wait for being charged can be determined using the proposed algorithm. Parameters can be varied freely, so the model is adequate for modeling different datasets

LV Grid Modeling Including Consumption and Distributed PV Generation with Focus on Voltage Profile

Distributed generation is growing rapidly and it poses challenges to grid operations, especially on LV network. A set of sample networks are created based on the Hungarian LV distribution network to study the effects of distributed generation. These models represent accurately the overall LV network structure. Thus, conclusions based on them are valid for the Hungarian LV distribution network. Consumer models are also constructed, with focus on random behavior, based on actual measurements. The model networks utilize PV generation - as this gives over 99% of the DG in Hungary. Simulations are carried out on this model set to find the limits of PV DG in the network by voltage profile, without any smart control. Overhead lines will face voltage problems - even with just a small amount of PV generation, while cable networks can keep a good voltage profile. Two simple regulation methods are also tested

Neutral Voltage Comparison of Different Grounding Configurations and Calculation Methods in Multi-Grounded Low Voltage Network

The steady growth in distributed generation brings more and more attention to low voltage (LV) distribution networks. Therefore, a good model is important to study these trends, especially with local regulation. Grounding the neutral line at multiple points along the network is a common practice in many European countries influencing neutral currents and voltages. Modelling grounding current had been of little interest at network planning and operation before, with only passive consumers. However, with the growing number of smart equipment, it becomes an overlooked, yet important issue. This equipment usually rely on local measurements and regulates accordingly. Given that most of the LV equipment uses single-phase connection, the neutral voltage is an important issue. Yet few papers study the neutral line behaviour and often overlook the effect of grounding. This article studies the effect of different grounding configurations on neutral voltages, and compares it with one of the most commonly used calculation method in literature that incorporates groundings. The differences are large enough to adversely affect local regulation

Performance Assessment of Integrating SMES and Battery Storage Systems with Renewable DC-bus Microgrids: A Comparison

The presence of renewable energy sources in hybrid renewable energy systems is considered a significant challenge since the generation mainly depends on meteorological conditions. Hence, employing a robust and flexible energy storage system is, therefore, a crucial solution in such circumstances. This paper investigates the performance evaluation of both batteries and superconducting magnetic energy storage (SMES) systems integrated with hybrid solar-wind DC-bus microgrid. The study focuses on enhancing the system stability using both storage technologies during normal and extreme renewables instabilities like wind gusts and shadows, and sudden load variations. Moreover, the load voltage/frequency were preserved constant during the distinct instabilities using the inverter control system. Productive findings showed the superior performance of utilizing the SMES over the batteries and its potential to enhance the system power-quality

Frequency of diarrhoea-associated viruses in swine of various ages in Hungary

Enteric viral diseases of swine are one of the most frequent disorders causing huge economic losses in pork production. After the reappearance of an emerging enteropathogen, porcine epidemic diarrhoea virus (PEDV) in Hungary in 2016, an extensive survey was initiated in an attempt to identify diarrhoea-related porcine viruses, including adeno-, astro-, boca-, calici-, circo-, corona-, kobu-, rota- and Torque teno viruses. A total of 384 faecal samples collected during a twoyear period from diarrhoeic and asymptomatic pigs of various ages in 17 farms were screened by conventional and real-time PCR methods. Half of the samples contained at least one examined virus with the dominance of kobuvirus (55.1%) followed by bocaviruses (33.2%) and rotavirus groups A and C together (20.9%), while coronaviruses including PEDV were not found in this set of samples. Statistical analysis showed a highly significant difference (P < 0.0001) in the frequency of single infections compared to mixed ones with the exception of weaned pigs, in which group additionally most viruses were detected. The results of this study suggest that the complexity of this disease may vary with age, which makes the prevention of diarrhoea a challenge, especially in weaned pigs

The Role of Hybrid Battery–SMES Energy Storage in Enriching the Permanence of PV–Wind DC Microgrids: A Case Study

The superior access to renewable sources in modern power systems increases the fluctuations in system voltage and power. Additionally, the central dilemmas in using renewable energy sources (RESs) are the intermittent nature of and dependence on wind speed and solar irradiance for wind and photovoltaic (PV) systems, respectively. Therefore, utilizing a vigorous and effective energy storage system (ESS) with RESs is crucial to overcoming such challenges and dilemmas. This paper describes the impacts of using a battery storage system (BSS) and superconducting magnetic energy storage (SMES) system on a DC bus microgrid-integrated hybrid solar–wind system. The proposed method employs a combination of BSS and SMES to improve the microgrid stability during different events, such as wind variation, shadow, wind turbine (WT) connection, and sudden PV outage events. Distinct control approaches are proposed to control the system’s different components in order to increase overall system stability and power exchange. Both the PV and wind systems are further equipped with unique maximum power point tracking (MPPT) controllers. Additionally, each of the ESSs is controlled using a proposed control method to supervise the interchange of the active power within the system and to keep the DC bus voltage constant during the different examined instabilities. Furthermore, to maintain the load voltage /frequency constant, the prime inverter is controlled using the proposed inverter control unit. The simulation results performed with Matlab/Simulink show that the hybrid BSS + SMES system successfully achieves the main targets, i.e., DC voltage, interchange power, and load voltage/frequency are improved and smoothed out. Moreover, a comparison among three case studies is presented, namely without using ESSs, using the BSS only, and once more using both BSS and SMES systems. The findings prove the efficacy of the proposed control method based on the hybrid BSS + SMES approach over BSS only in preserving the modern power system’s stability and reliability during the variable events