GIOVANNI LUCCA - Academia.edu (original) (raw)

Papers by GIOVANNI LUCCA

2010 30th International Conference on Lightning Protection (ICLP), 2010

This paper presents an algorithm, based on a Monte Carlo method, to assess the yearly expected nu... more This paper presents an algorithm, based on a Monte Carlo method, to assess the yearly expected number of failures to buried optical fibre cables due to direct lightning strokes. The random parameters that have been considered in the calculation model are the lightning peak current, the distance between the cable and the point of impact of the stroke to soil and the cable failure current (i.e. the minimum value of the lightning peak current able to produce a failure on the optical fibre cable). The occurrence of the cable failures is then associated to a time Poisson stochastic process.

Applied Medical Informaticvs, 2020

The paper presents formulas and conditions relevant to the construction of chains of mutually tan... more The paper presents formulas and conditions relevant to the construction of chains of mutually tangent ellipses inscribed inside a parabola. Moreover, some connections with certain integer sequences and Pythagorean triplets are shown.

We consider a generic circles chain that can be drawn inside a circular segment and we show some ... more We consider a generic circles chain that can be drawn inside a circular segment and we show some geometric properties related to the chain itse lf. We also give recursive and non recursive formulas for calculating th e centers coordinates and the radius of the circles.

This paper deals with the evaluation of the inductive coupling between an overhead finite length ... more This paper deals with the evaluation of the inductive coupling between an overhead finite length wire circuit and a buried wire circuit, both with earth return, in the range of Extremely Low Frequencies (ELF). In particular, the attention is focused on the key parameter for this kind of problems i.e. the per unit length (p.u.l.) mutual impedance between the two circuits. Starting from the exact formula involving a Sommerfeld’s integral, two new approximated analytical formulas, having different levels of approximation, are derived; the advantage of these formulas is that, in such a way, the p.u.l. mutual impedance is expressed only by means of elementary functions so avoiding numerical calculations of the Sommerfeld’s integral. Finally, a comparison between the two proposed formulas is made.

We derive the conditions for inscribing, inside a circular segment, a chain of mutually tangent c... more We derive the conditions for inscribing, inside a circular segment, a chain of mutually tangent circles having the property that the ratio between th largest circle radius and the radius of any other circle of the chain is an inte ger number.

IET Science, Measurement & Technology

Progress In Electromagnetics Research M

This paper deals with the influence of steel non-linearity when calculating the induced current/v... more This paper deals with the influence of steel non-linearity when calculating the induced current/voltage on a pipeline circuit with earth return under 50-60 Hz induction by power lines or electrified railway lines. By having at disposal the measured curves of the per unit length pipe internal impedance versus the current flowing in it, one can calculate induced voltage and current on the pipelineearth circuit by means of the successive approximations method.

IET Science, Measurement & Technology

The study generalises the calculation method described by Lucca, devoted to the evaluation of ind... more The study generalises the calculation method described by Lucca, devoted to the evaluation of induced voltage and current on a pipeline due to a nearby overhead power line in a fault condition, from the case of homogeneous soil to the case of a two-layer soil. By means of some examples of calculation, it is put in evidence that the homogeneous soil hypothesis can lead, in some cases, to excessively precautionary results and, in other cases, to underestimated results. Therefore, a calculation method based on the two-layer soil model seems a better approach.

Progress In Electromagnetics Research M

The context of the paper is the 50-60 Hz electromagnetic interference between AC power lines/elec... more The context of the paper is the 50-60 Hz electromagnetic interference between AC power lines/electrified railway lines and pipelines; we present here an algorithm for the evaluation of the AC induced current density, flowing through the holidays (defects) in the pipeline insulating coating, from pipe to soil by modelling this last one as a two-layer structure. Moreover, the value of holidays area is treated as a random variable (as actually is from field experience) so allowing to associate a certain level of probability to the event of exceeding the AC current density limit, established by standards, for AC corrosion risk. The results show that the surface layer soil resistivity is a very significant factor influencing the level of AC induced current density.

IET Science, Measurement & Technology

IET Science, Measurement & Technology

International Transactions on Electrical Energy Systems

IET Science, Measurement & Technology

IET Science, Measurement & Technology

Eur Trans Electr Power, 2010

This paper should be intended as a contribution to the evaluation of the extremely low frequency ... more This paper should be intended as a contribution to the evaluation of the extremely low frequency (ELF) magnetic field produced by power lines in the context of the human exposure to the magnetic field itself; in particular, we consider those situations where the actual geometry of the conductors and the lay-out of the power line(s) have to be taken into account in order to correctly calculate the field. The main implication is that a 3D model of power line has to be used instead of the simpler 2D model which is based on the Biot-Savart law applied to rectilinear and infinite wires. Purpose of this paper is to give operational formulas to be directly applied in all those situations where a 3D evaluation of the magnetic field is needed in order to quantify the environmental impact of one or more power lines on a certain part of the territory.

A boundary integral numerical method for the dynamics of nonspherical cavitation bubbles in invis... more A boundary integral numerical method for the dynamics of nonspherical cavitation bubbles in inviscid incompressible liquids is described. Only surface values of the velocity potential and its first derivatives are involved. The problem of solving the Laplace equation in the entire domain occupied by the liquid is thus avoided. The collapse of a bubble in the vicinity of a solid

European Transactions on Electrical Power, Apr 1, 2010

The need to shield ELF (extremely low frequency) magnetic fields generated by power and industria... more The need to shield ELF (extremely low frequency) magnetic fields generated by power and industrial installations arises for two main reasons: the first one is a typical EMC (electromagnetic compatibility) problem related to possible interference among electric and electronic devices while the second one is related to potential health effects due to magnetic field exposure. Different techniques exist to reduce the magnetic field mainly depending on the kind of source considered; here we treat only the shielding action offered by long and metallic structures like slabs, sheets, and foils with respect to the field produced by long sources like power cables, bus-bars, and wires. In particular, we focus our attention on magnetic metallic shields where the shielding action is due to both 'magnetic flux shunting' and 'eddy current cancellation' mechanisms. From the design point of view, it is useful to have at disposal a calculation tool able to predict the magnetic field reduction, in a given region of space, as a function of the shield characteristics (geometry, material) and source characteristics (conductors disposition, distance from the shield). The typical calculation technique used in this kind of problem is based on the finite elements method (FEM) that is broadly described in the technical literature. Here, we want to propose a different approach that is based on integral equations (IE) and is able to model shields made by materials like iron, steel, and mumetal having both conductive and magnetic properties; nevertheless, as special cases, the algorithm is also able to deal with purely conductive shields like copper and aluminium, (frequently used in applications) where only the eddy current shielding action exists, and with purely magnetic shields, under the action of a d.c. source, where only the magnetic flux shunting effect is present. The main hypothesis that is necessary to adopt in the model is the linear behaviour of the magnetic material; such hypothesis is certainly reasonable in many real situations where the material is far from saturation. N wires conductors each carrying a stationary current I i (i ¼ 1, 2,..,N) at a frequency f (typically 50 or 60 Hz); these currents are the sources of the magnetic field that has to be reduced. An homogeneous shield characterized by conductivity s and relative magnetic permeability m r >>1; the shape of the shield can be arbitrary, even if in it is represented, for the sake of simplicity, a planar shield.

2010 30th International Conference on Lightning Protection (ICLP), 2010

This paper presents an algorithm, based on a Monte Carlo method, to assess the yearly expected nu... more This paper presents an algorithm, based on a Monte Carlo method, to assess the yearly expected number of failures to buried optical fibre cables due to direct lightning strokes. The random parameters that have been considered in the calculation model are the lightning peak current, the distance between the cable and the point of impact of the stroke to soil and the cable failure current (i.e. the minimum value of the lightning peak current able to produce a failure on the optical fibre cable). The occurrence of the cable failures is then associated to a time Poisson stochastic process.

Applied Medical Informaticvs, 2020

The paper presents formulas and conditions relevant to the construction of chains of mutually tan... more The paper presents formulas and conditions relevant to the construction of chains of mutually tangent ellipses inscribed inside a parabola. Moreover, some connections with certain integer sequences and Pythagorean triplets are shown.

We consider a generic circles chain that can be drawn inside a circular segment and we show some ... more We consider a generic circles chain that can be drawn inside a circular segment and we show some geometric properties related to the chain itse lf. We also give recursive and non recursive formulas for calculating th e centers coordinates and the radius of the circles.

This paper deals with the evaluation of the inductive coupling between an overhead finite length ... more This paper deals with the evaluation of the inductive coupling between an overhead finite length wire circuit and a buried wire circuit, both with earth return, in the range of Extremely Low Frequencies (ELF). In particular, the attention is focused on the key parameter for this kind of problems i.e. the per unit length (p.u.l.) mutual impedance between the two circuits. Starting from the exact formula involving a Sommerfeld’s integral, two new approximated analytical formulas, having different levels of approximation, are derived; the advantage of these formulas is that, in such a way, the p.u.l. mutual impedance is expressed only by means of elementary functions so avoiding numerical calculations of the Sommerfeld’s integral. Finally, a comparison between the two proposed formulas is made.

We derive the conditions for inscribing, inside a circular segment, a chain of mutually tangent c... more We derive the conditions for inscribing, inside a circular segment, a chain of mutually tangent circles having the property that the ratio between th largest circle radius and the radius of any other circle of the chain is an inte ger number.

IET Science, Measurement & Technology

Progress In Electromagnetics Research M

This paper deals with the influence of steel non-linearity when calculating the induced current/v... more This paper deals with the influence of steel non-linearity when calculating the induced current/voltage on a pipeline circuit with earth return under 50-60 Hz induction by power lines or electrified railway lines. By having at disposal the measured curves of the per unit length pipe internal impedance versus the current flowing in it, one can calculate induced voltage and current on the pipelineearth circuit by means of the successive approximations method.

IET Science, Measurement & Technology

The study generalises the calculation method described by Lucca, devoted to the evaluation of ind... more The study generalises the calculation method described by Lucca, devoted to the evaluation of induced voltage and current on a pipeline due to a nearby overhead power line in a fault condition, from the case of homogeneous soil to the case of a two-layer soil. By means of some examples of calculation, it is put in evidence that the homogeneous soil hypothesis can lead, in some cases, to excessively precautionary results and, in other cases, to underestimated results. Therefore, a calculation method based on the two-layer soil model seems a better approach.

Progress In Electromagnetics Research M

The context of the paper is the 50-60 Hz electromagnetic interference between AC power lines/elec... more The context of the paper is the 50-60 Hz electromagnetic interference between AC power lines/electrified railway lines and pipelines; we present here an algorithm for the evaluation of the AC induced current density, flowing through the holidays (defects) in the pipeline insulating coating, from pipe to soil by modelling this last one as a two-layer structure. Moreover, the value of holidays area is treated as a random variable (as actually is from field experience) so allowing to associate a certain level of probability to the event of exceeding the AC current density limit, established by standards, for AC corrosion risk. The results show that the surface layer soil resistivity is a very significant factor influencing the level of AC induced current density.

IET Science, Measurement & Technology

IET Science, Measurement & Technology

International Transactions on Electrical Energy Systems

IET Science, Measurement & Technology

IET Science, Measurement & Technology

Eur Trans Electr Power, 2010

This paper should be intended as a contribution to the evaluation of the extremely low frequency ... more This paper should be intended as a contribution to the evaluation of the extremely low frequency (ELF) magnetic field produced by power lines in the context of the human exposure to the magnetic field itself; in particular, we consider those situations where the actual geometry of the conductors and the lay-out of the power line(s) have to be taken into account in order to correctly calculate the field. The main implication is that a 3D model of power line has to be used instead of the simpler 2D model which is based on the Biot-Savart law applied to rectilinear and infinite wires. Purpose of this paper is to give operational formulas to be directly applied in all those situations where a 3D evaluation of the magnetic field is needed in order to quantify the environmental impact of one or more power lines on a certain part of the territory.

A boundary integral numerical method for the dynamics of nonspherical cavitation bubbles in invis... more A boundary integral numerical method for the dynamics of nonspherical cavitation bubbles in inviscid incompressible liquids is described. Only surface values of the velocity potential and its first derivatives are involved. The problem of solving the Laplace equation in the entire domain occupied by the liquid is thus avoided. The collapse of a bubble in the vicinity of a solid

European Transactions on Electrical Power, Apr 1, 2010

The need to shield ELF (extremely low frequency) magnetic fields generated by power and industria... more The need to shield ELF (extremely low frequency) magnetic fields generated by power and industrial installations arises for two main reasons: the first one is a typical EMC (electromagnetic compatibility) problem related to possible interference among electric and electronic devices while the second one is related to potential health effects due to magnetic field exposure. Different techniques exist to reduce the magnetic field mainly depending on the kind of source considered; here we treat only the shielding action offered by long and metallic structures like slabs, sheets, and foils with respect to the field produced by long sources like power cables, bus-bars, and wires. In particular, we focus our attention on magnetic metallic shields where the shielding action is due to both 'magnetic flux shunting' and 'eddy current cancellation' mechanisms. From the design point of view, it is useful to have at disposal a calculation tool able to predict the magnetic field reduction, in a given region of space, as a function of the shield characteristics (geometry, material) and source characteristics (conductors disposition, distance from the shield). The typical calculation technique used in this kind of problem is based on the finite elements method (FEM) that is broadly described in the technical literature. Here, we want to propose a different approach that is based on integral equations (IE) and is able to model shields made by materials like iron, steel, and mumetal having both conductive and magnetic properties; nevertheless, as special cases, the algorithm is also able to deal with purely conductive shields like copper and aluminium, (frequently used in applications) where only the eddy current shielding action exists, and with purely magnetic shields, under the action of a d.c. source, where only the magnetic flux shunting effect is present. The main hypothesis that is necessary to adopt in the model is the linear behaviour of the magnetic material; such hypothesis is certainly reasonable in many real situations where the material is far from saturation. N wires conductors each carrying a stationary current I i (i ¼ 1, 2,..,N) at a frequency f (typically 50 or 60 Hz); these currents are the sources of the magnetic field that has to be reduced. An homogeneous shield characterized by conductivity s and relative magnetic permeability m r >>1; the shape of the shield can be arbitrary, even if in it is represented, for the sake of simplicity, a planar shield.