New methodology for the prediction of motor starting effect on bus voltages of interconnected power systems

A new methodology is proposed in this paper capable of predicting the impact of induction motor load starting on the bus voltages of an interconnected power system. The profile of the voltage sag is predicted for each bus, which is used to improve the power quality of a system. The methodology is investigated with the use of a four bus, as well as fourteen bus IEEE interconnected system. Mathematical and simulation results demonstrate the effectiveness and applicability of the proposed methodology for the application

Multicell Power Supplies for Improved Energy Efficiency in the Information and Communications Technology Infrastructures

The rapid growth of the Information and Communications Technology (ICT) sector requires additional infrastructure, such as more micro-datacenters and telecom stations, to support the higher internet speeds and low latency requirements of 5G networks. The increased power requirements of the new ICT technologies necessitate the proposal of new power supplies, in an attempt to support the increase in energy demand and running costs. This work provides an in-depth theoretical analysis on the losses of the individual stages of commercially available PSU and proposes a new multicell PSU, the buck PFC converter, which offers a higher overall efficiency at varying load levels. The theoretical results are verified using simulation results, via a PSIM Thermal Module, and using experimental data. The results indicate that multicell structures can improve the overall PSU efficiency by 1.2% at 50% rated power and more than 2.1% at full power. Finally, taking into consideration the economic implications of this study, it is shown that the proposed multicell structure may increase the PSU costs by 10.78%, but the payback period is in the order of just 3.3 years

Photovoltaic grid-forming control strategy investigation using hardware-in-the-loop experiments

The frequency stability of a power system is of paramount importance, as a fast frequency swings in the system can lead to oscillatory instability, and thereby blackouts. A grid-connected microgrid, that can operate in the islanded mode can also possess such deteriorating effect due to the higher share of converter-based sources. In this paper, a coordinated frequency control within a distribution network is discussed, with a higher share of Photovoltaics (PV). The main objective of this paper is to test the grid-forming capabilities of PVs, without the requirement of an energy storage in the network. The tests were carried out with the help of the Typhoon Hardware-in-the-loop (HIL) platform using a real Cypriot network feeder. The real-time results confirm the efficacy of the PV as a grid-forming inverter, provided it has sufficient input (irradiance) to provide for the loads within the system of interest. The grid-forming PV also possesses the capability of reconnection with the utility grid through a synchronizer switch that requires minimal communication, makes the overall control independent of any other power source, subject to certain irradiance and loading conditions.Comment: 13th Mediterranean Conference on Power Generation, Transmission, Distribution and Energy Conversion (MEDPOWER 2022

Dynamically Reconfigurable SIR Filter Using Rectenna and Active Booster

Obrađeni su populacijski parametri čaglja (Cannis aureus L.) u proteklom desetogodišnjem razdoblju. Istraživanjem su se obuhvatila lovišta koja pripadaju širem području plavljenja rijeke Save. Rezultati ovog istraživanja pomažu boljem razumijevanju dinamike populacije čaglja i širenju areala ove vrste koja je već prisutna na čitavom prostoru Republike Hrvatske

Identification of voltage sag indices in electrical power systems

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Investigation into the compatibility and effectiveness of a new mathematical online voltage sag index

A new mathematical index is investigated in this paper which improves the power quality of a system through providing a tool for online voltage sag mitigation. The index is developed mathematically and applied on transmission and distribution networks. Furthermore, it is verified for its compatibility through the use of a tap changing transformer scheme. Two loading variation scenarios, consisting of induction motors are investigated for each type of network, in order to establish the effectiveness and accuracy of the index. © 2010 Inderscience Enterprises Ltd

Contribution of distributed generators to the harmonic distortion in low voltage power network

In the last 20 years immense efforts have been made to utilize renewable energy sources for electric power generation. This paper investigates some aspects of integration of the distributed generators into the low voltage distribution network. An assessment of impact of the distributed generators on the voltage and current harmonic distortion in the low voltage network is performed. Results obtained from a case study, using real-life low voltage network, are presented and discussed

A high granularity state-space method for contaminant detection and isolation in intelligent buildings

Conservation of the Indoor Air Quality is essential in modern, energy efficient, intelligent buildings. However, accidents or malicious acts that often result in various airborne contaminant releases can endanger the occupants' wellbeing. In this work, an indoor air quality monitoring methodology is presented for detecting and localizing a contaminant source in the 3D indoor environment. Specifically, a state-space model is used to describe the contaminant dispersion in a zone which is discretised into multiple cuboid cells. The airflow exchange between the cells is computed based on a 3D discretized coarse-grid CFD analysis. A contaminant detection and localization methodology that considers modelling uncertainty and measurement noise, is adapted and applied to the CFD-based state-space model for detecting the existence of a possible contaminant source and estimating its location within the zone. The performance of the approach is illustrated through simulation examples