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This paper focuses on the employment of analytical methods for reliability/availability assessment of HVDC-VSC point-to-point connections. In particular, underground XLPE cable links are investigated and an exemplificative calculation for a typical layout is carried out. Key reliability features of state-of-the-art modular multilevel converters (MMC) are highlighted. Closed-form reliability equations,...
In this paper, a procedure based on three-dimension matrices is presented: it is the generalization of multiconductor cell analysis to any transmission line where the positions of all the active and passive conductors may change with continuity along their development. A meaningful example of this is given by three-core single lead-screened armoured cables where cores and armour wires are wound helically...
The continuously growing electrical power demand is more and more faced by the increase of generation from renewable energy sources. Given the uneven distribution of those resources in the power system, an increase in the transmission lines current rating (also called ampacity) is expected in the next future, to avoid the formation of bottlenecks. Given the difficulties in building new lines, due...
The paper presents a modelling approach which, starting from experimental measurements, allows automatically deriving a lithium-ion battery electrical model. This procedure is applied to a 47.7 kW lithium-manganese oxide battery unit in order to infer a third-order Thevenin equivalent electrical model of the unit itself. By means of a matrix representation of specific experimental measurements, it...
In this paper a single-ended travelling wave-based fault location algorithm is presented with reference to HV (60 kV) overhead unearthed operated lines:the time-frequency characteristics of the travelling wave signal are processed by utilising the phase to modal transformation and the continuous wavelet one. The frequency components of the processed signals are used for the travelling wave speed calculation...
The paper describes the instantaneous control technique of a two stage Power Conversion System interfaced to an energy storage equipment. The control aims at regulating the active and reactive power exchange between the grid and the converter during the battery discharge and charge operations. The results of the control implementation in a Simulink® model of the Power Conversion System are compared...
This paper deals with tunnel installations of extra high voltage (EHV) power cables. Cross-bonding of the screens remains the usual earthing arrangements of cable systems, if their extension is greater than 1,5 km approximately. Such EHV cable systems need a functional earthing along the route in correspondence of each major section, at the sending and at the receiving ends. Given the difficulties...
Reliability of underground Extra High Voltage (EHV) cable systems is undermined by third party mechanical damages. In order to prevent long and expensive outages, the Italian TSO equipped some cable lines of strategical importance with additional protective structures. The presence of highly permeable and conductive material surrounding the cable installations has risen concerns about potential variations...
This paper provides a coherent classification of the existing methods for phase-to-ground fault location in power sub-transmission networks operated with unearthed neutral. The theoretical background of every approach is briefly presented, specifying whether each method is applicable on-line or off-line. The analysis is mainly focused on comparing the limitations of the algorithms, especially concerning...
The paper presents the analysis of Sodium Nickel chloride batteries in transient operation, and proposes a very simple but quite precise model to represent both the transient and steady battery behaviours. The used modelling approach is based on steady state experimental measures. Sodium Nickel chloride batteries are one of the most promising technologies for electrical energy stationary storage in...
The purpose of this paper is to present a reliable modelling of sodium-chloride battery in Simulink environment in order to have a powerful tool which is able to foresee the battery behaviour in both discharge and charge operations. The model is based on a wide set of measures (e.g. discharge and charge resistance for different depth of discharge and current rates, etc.). A comparison between the...
The paper deals with a typical microgrid operating in an islanded mode. The microgrid is energized by a few power sources, namely a mini-hydroelectric plant, a diesel generator set and a photovoltaic field, and supplies both critical and noncritical loads. After modeling the power sources and illustrating both their management and that one of the microgrid, a computer-assisted analysis of the frequency...
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