Search results for "power system"

Design and Performance of a High Temperature Superconducting Axial Flux Generator

2013

In this paper, a high temperature axial flux (HTSAF) generator is presented. In this generator the excitation of the generator is obtained by using some high temperature superconducting magnets. In order to reduce the negative effects of vibrations, the excitation is located on the stationary part of the generator. Starting, running and endurance tests of the machine are presented.

Characterization and Error Compensation of a Rogowski Coil in the Presence of Harmonics

2011

This paper reports the results of an experimental study dealing with a commercial Rogowski coil current transducer (RCCT) in the presence of harmonic distortion. The RCCT was observed under two conditions: 1) sinusoidal excitation with frequencies from 50 to 750 Hz and 2) nonsinusoidal excitation using fundamental frequency and one harmonic, with adjustable amplitude and phase shift. The experimental results show only a weak dependence of the harmonic current ratio error and phase displacement on the amplitude and phase shift of the excitation harmonic. The phase displacement is also independent of the conductor position within the Rogowski coil window. An error compensation method, based o…

Green Data Centres integration in smart grids: New frontiers for ancillary service provision

2017

Abstract The paper presents a study, conceived within the GEYSER FP7 co-funded European research project, on the ancillary services that Green Data Centres (GDCs) can provide, focusing, in particular, on spinning reserve. More in detail, the main contribution of the paper is to show how GDCs can be involved in the secondary frequency regulation process of a smart distribution grid, for contrasting the disturbing effects of unexpected variation of the energy production. With this aim, a real data centre, owned by Engineering S.p.A., is simulated as connected to the Medium Voltage IEEE 14-bus test grid where some RES-based generators are supposed to exist. Simulations are carried out in order…

Fuel cells for household appliances: Experimental test of power management algorithms

2013

In this paper, fuel cell - based hybrid power supplies for household appliances are addressed. The profile of residential power consumption is evaluated during working, non-working days in both summer and winter periods. The worst-case load power demand is therefore highlighted. A 5kW Nuvera PowerFlow proton exchange membrane fuel cell for household appliances is tested. On the basis of the characterization of the fuel cell stack under test, stand-alone and fuel cell - battery active hybrid power supply architectures are both considered. Experimental validation of three power management algorithms is proposed in terms of hydrogen consumption, cost and energy saving. Power management algorit…

Power management of grid-connected photovoltaic inverter with storage battery

2011

With increased penetration of PV generation in the power grid, it becomes necessary to control the PV generation similar to the conventional power sources. Grid-connected PV systems equipped with storage batteries are capable of active power control. PV power generation can be either fed into the grid or stored in the battery. This paper presents a deterministic power management algorithm that uses closed-form approximations derived from analytical loss models. It can be configured to maximize the efficiency or the revenue in a liberalized electricity market. The battery controller emulates an optimum load-line in which the PV power is autonomously shared between the battery and the feed-in…

Power system consumption model using SPICE

2014

Space missions have very stringent mass, volume and also power budgets. This requires very precise knowledge of the power consumption of the whole satellite, not only peak power but also static and long term dynamic power. This calculation becomes very complex if all the operational modes (long term dynamic changes) are taken into account, including the different environmental situations. The power budget of any Power Converter Module (PCM), which includes not only the DC/DC converter but also the distribution unit, depends on the power it delivers and on external factors like temperature and input voltage. We propose to use a linear SPICE model using electronic models of discrete component…

Hydrogen back-up power system with photovoltaic direct energy transfer regulation and interleaved boost for space applicattions

2012

This work details a power conditioning unit for photovoltaic/hydrogen based energy systems in space applications. The power conversion techniques applied are similar to the ones used on photovoltaic/battery space power systems. A direct energy transfer photovoltaic regulator is devised for feeding two outputs; the first output corresponds to the main unregulated battery bus and the second output sets a power path to feed an electrolyser. A modular fuel cell converter completes the system and operates when photovoltaic energy is not available or load demand exceeds the generated photovoltaic power, providing electrical power from a fuel cell. An ancillary battery, located in the main bus, di…

PV System Design for Off-Grid Applications

2015

Solar photovoltaic (PV) technology has the versatility and flexibility for developing off-grid electricity system for different regions, especially in remote rural areas. While conventionally straight forward designs were used to set up off-grid PV-based system in many areas for wide range of applications, it is now possible to adapt a smart design approach for the off-grid solar PV hybrid system. A range of off-grid system configurations are possible, depending upon load requirements and their electrical properties as well as on site-specific available energy resources. The overall goal of the off-gird system design should be such that it should provide maximum efficiency, reliability and …

Achieving maximum power transfer in a multi-source renewable system

2014

Frequency dynamics of power systems with temporally distributed disturbances

2021

Abstract The frequency dynamics and stability of power systems is essentially affected by nature and characteristics of the disturbances occurring in the system. Conventionally, frequency transients are examined assuming a single disturbance applied at a given time. However, actual incidents in the power systems can be generally composed of a temporal sequence of events, and thus characterized by multiple power imbalances of different magnitudes and time offsets. The consideration of the effects of the temporal distribution of power imbalances is important for two main reasons: the impact on the frequency dynamics of the system in terms of frequency metrics such as minimum instantaneous fre…