Current Interruption in AC Networks

2017 ◽  
pp. 129-164
Author(s):  
J.C. Das
Keyword(s):  
Current Interruption ◽  
Ac Networks

scholarly journals State-Space Model of Quasi-Z-Source Inverter-PV Systems for Transient Dynamics Studies and Network Stability Assessment

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4150
Author(s):  
Lluís Monjo ◽  
Luis Sainz ◽  
Juan José Mesas ◽  
Joaquín Pedra
Keyword(s):  
Power Systems ◽  
State Space ◽  
State Space Model ◽  
Pv System ◽  
Pv Systems ◽  
Renewable Power ◽  
Ac Networks ◽  
Transient Interactions ◽  
The Stability ◽  
Averaged Model

Photovoltaic (PV) power systems are increasingly being used as renewable power generation sources. Quasi-Z-source inverters (qZSI) are a recent, high-potential technology that can be used to integrate PV power systems into AC networks. Simultaneously, concerns regarding the stability of PV power systems are increasing. Converters reduce the damping of grid-connected converter systems, leading to instability. Several studies have analyzed the stability and dynamics of qZSI, although the characterization of qZSI-PV system dynamics in order to study transient interactions and stability has not yet been properly completed. This paper contributes a small-signal, state-space-averaged model of qZSI-PV systems in order to study these issues. The model is also applied to investigate the stability of PV power systems by analyzing the influence of system parameters. Moreover, solutions to mitigate the instabilities are proposed and the stability is verified using PSCAD time domain simulations.

scholarly journals A Planning Tool for Reliability Assessment of Overhead Distribution Lines in Hybrid AC/DC Grids

2021 ◽  
Vol 13 (11) ◽  
pp. 6099
Author(s):  
Giovanna Adinolfi ◽  
Roberto Ciavarella ◽  
Giorgio Graditi ◽  
Antonio Ricca ◽  
Maria Valenti
Keyword(s):  
Reliability Assessment ◽  
Reliability Function ◽  
Climatic Conditions ◽  
Planning Tool ◽  
Grid Resource ◽  
Distribution Lines ◽  
Ac Networks ◽  
Reliability Performance ◽  
Power Dispatching

Integration of DC grids into AC networks will realize hybrid AC/DC grids, a new energetic paradigm which will become widespread in the future due to the increasing availability of DC-based generators, loads and storage systems. Furthermore, the huge connection of intermittent renewable sources to distribution grids could cause security and congestion issues affecting line behaviour and reliability performance. This paper aims to propose a planning tool for congestion forecasting and reliability assessment of overhead distribution lines. The tool inputs consist of a single line diagram of a real or synthetic grid and a set of 24-h forecasting time series concerning climatic conditions and grid resource operative profiles. The developed approach aims to avoid congestions criticalities, taking advantage of optimal active power dispatching among “congestion-nearby resources”. A case study is analysed to validate the implemented control strategy considering a modified IEEE 14-Bus System with introduction of renewables. The tool also implements reliability prediction formulas to calculate an overhead line reliability function in congested and congestions-avoided conditions. A quantitative evaluation underlines the reliability performance achievable after the congestion strategy action.

scholarly journals Auditory cortical micro-networks show differential connectivity during voice and speech processing in humans

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Florence Steiner ◽  
Marine Bobin ◽  
Sascha Frühholz
Keyword(s):  
Speech Processing ◽  
Neural Circuits ◽  
Brain Activity ◽  
Inhibitory Pathways ◽  
Ac Networks ◽  
Directional Connectivity ◽  
The Right ◽  
Voice Processing ◽  
Differential Connectivity ◽  
Voice And Speech

AbstractThe temporal voice areas (TVAs) in bilateral auditory cortex (AC) appear specialized for voice processing. Previous research assumed a uniform functional profile for the TVAs which are broadly spread along the bilateral AC. Alternatively, the TVAs might comprise separate AC nodes controlling differential neural functions for voice and speech decoding, organized as local micro-circuits. To investigate micro-circuits, we modeled the directional connectivity between TVA nodes during voice processing in humans while acquiring brain activity using neuroimaging. Results show several bilateral AC nodes for general voice decoding (speech and non-speech voices) and for speech decoding in particular. Furthermore, non-hierarchical and differential bilateral AC networks manifest distinct excitatory and inhibitory pathways for voice and speech processing. Finally, while voice and speech processing seem to have distinctive but integrated neural circuits in the left AC, the right AC reveals disintegrated neural circuits for both sounds. Altogether, we demonstrate a functional heterogeneity in the TVAs for voice decoding based on local micro-circuits.

Application of controlled switching to 500-kV shunt reactor current interruption

2003 ◽  
Vol 18 (2) ◽  
pp. 480-486 ◽  
Author(s):  
T. Kobayashi ◽  
S. Tsukao ◽  
I. Ohno ◽  
T. Koshizuka ◽  
S. Nishiwaki ◽  
...  
Keyword(s):  
Current Interruption ◽  
Shunt Reactor ◽  
Controlled Switching
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