Overhead power line with seven-phase supports

Abstract

An overhead power line (1) comprises seven-phase supports (2a), each having seven connecting attachments (5) supporting seven respective electrical phases (3). The connecting attachments (5) of each seven-phase support (2a) comprise a central connecting attachment (52) and six peripheral connecting attachments (51), arranged so that the respective electrical phases (3) are at the vertices of a hexagonal polygon, preferably a regular hexagon. The six peripheral connecting attachments (51) support six electrical phases (3), which are three electrical phases of a first set (31a, 31b, 31c) and three electrical phases of a second set (32a, 32b, 32c) of homologous phases, arranged alternately with each other, while the central connecting attachment (52) supports at least one electrical phase of a third set (33) of homologous phases. Compared to the double-circuit power lines, they improve various technical performances, among which there is a reduction in magnetic induction in the surrounding environment, and it also improves the social and environmental impact of the power line, allowing existing power lines to be upgraded.

Description

[0001] TITLE: "Overhead power line with seven-phase supports".

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention is developed in the field of overhead electric lines for the transmission and / or distribution of electrical energy.

[0005] Prior art

[0006] Overhead power lines commonly used in power grids, characterized by a three- phase type transmission and / or distribution system, have three-phase (single-circuit) or six-phase (double-circuit) supports.

[0007] In this sector, the number of phases indicates the number of active conductors or bundles of conductors supported by the support. Therefore, the six-phase doublecircuit electrical lines are understood as lines in which the phases are two by two homologous and therefore referable, in a three-phase system, to three sets having an electrical phase shift of the voltages equal to 120 electrical degrees.

[0008] The overhead double-circuit electrical lines typically accommodate two electrical connections and have, with the same electrical voltage, an increase in transportable electrical power compared to those with single circuit, with respect to a slightly higher occupation of the territory than those with single circuit and therefore have found wide application in the electric power transmission and distribution systems.

[0009] Among the overhead double-circuit electrical lines, those with a symmetrical arrangement of the phases with respect to a vertical plane are common (Figure la), in the sense that for each pair of homologous phases (R, R’ - S, S’ - T, T’) the two conductors are placed alongside at the same height, while for double-circuit ones with an anti-symmetrical arrangement of the phases (Figure lb) the conductors in a median position correspond to the homologous phases S, S’ while the low conductors R, T’ have the homologous R’, T in the high and diametrically opposite position.

[0010] The performance of a double-circuit line, in terms of the magnetic and electric field generated, is usually better in the case of an anti-symmetrical arrangement of the phases with the same current and electrical power transmitted, compared to a doublecircuit line with a symmetrical arrangement.

[0011] In turn, the performance of a double-circuit line with a symmetrical arrangement of the phases, in terms of the magnetic and electric field generated, is usually better with the same current and electrical power transmitted, compared to a single-circuit line.

[0012] Each overhead power line needs to have a sufficiently free space around it, to allow electrical operation in coexistance with infrastructures, vegetation and, in general, with the surrounding human activities.

[0013] Among the most stringent constraints that determine the area of the territory occupied by an overhead power line is that of the electric and magnetic fields produced by the line. In this sense, many regulations and legislations require compliance with specific exposure limits to electric and magnetic fields.

[0014] Therefore, on the one hand, new buildings for residential use cannot be built too close to an existing power line. On the other hand, in order to create a new overhead power line, it is necessary to find a corridor, on the territory, of certain dimensions that is sufficiently free from buildings housing the receptors. If an existing overhead electrical line were to be upgraded, with the same geometry of the supports, and therefore the same operating voltage, a greater electric current and electric power would affect the electrical connection, with a consequent proportional increase in the magnetic field generated. This is often not permissible due to the presence of buildings, for residential use or prolonged daily stays, with magnetic field values already close to the legislative limits.

[0015] In terms of magnetic field, the electrical lines with underground cable have, with the same voltage and electric current transmitted, an occupation of the territory, due to the magnetic field generated, lower than that of an overhead power line; this at the expense of a higher cost of infrastructure, greater complexity of construction, operation and maintainability.

[0016] Patent application WO2023214215, on behalf of the Applicant, proposes a five- phase overhead electrical line with the advantage of being able to obtain, with the same voltage and electric current transmitted, a significant reduction in the magnetic field on the anthropized areas present, or, with the same magnetic field on the territory, a significant increase in the electric current transmittable from the overhead line.

[0017] Summary of the invention

[0018] The aim of the present invention is to realize an overhead power line with performances that achieve even better performances, both from the point of view of reducing the occupation of the territory for the magnetic field, with the same voltage and electric current transmitted, and from the point of view of the greater current and electrical power that can be transmitted, with the same occupation of the territory, due to the magnetic field generated.

[0019] This and other aims are achieved by a seven-phase overhead power line and a method for renovating an existing overhead power line, according to any one of the appended claims.

[0020] The invention provides that the electrical line includes one or more seven-phase supports, with a support portion and a head portion. The head portion has seven connecting attachments supporting seven respective electrical phases. The connecting attachments comprise a central and six peripheral attachments, the latter arranged, in a projection, on a plane transverse to the axis of the electrical line, at the vertices of a hexagonal, preferably regular, polygon. The six peripheral attachments support six electrical phases, including a first circuit of mutually homologous electrical phases as well as a second circuit of mutually homologous electrical phases. The phases of the first and second circuit are arranged alternately according to the vertices of the hexagonal polygon and around the central attachment supporting a further circuit of electrical phases or the same grouped in a single phase (Figures lOa-lOb).

[0021] The Applicant pursued the design of the structure of the new supports such as to accommodate this particular geometry of the electrical phases capable of determining a resulting effect of "confinement" of the magnetic field generated within the hexagon geometry, between the central phase and the external phases. The result of all this is a strong containment of the magnetic field produced outside the aforesaid electrical line. This effect is even more significant than the five-phase line of WO 2023214215, offering performance comparable to that of an underground cable connection consisting of two circuits considered in the ideal condition of cloverleaf installation and optimised sequence of electrical phases.

[0022] In more detail, the resulting effect is maximum when the geometry of the electrical phases coincides with the vertices of a regular hexagon while the central phase is in the geometric centre of the same hexagon, thus resulting in a mutual arrangement of the phases according to six equilateral triangles (Figure 10b). The Applicant considers that a further increase in the number of electrical phases, although leading to an improvement in the magnetic behaviour, causes an operational complexity, such as to make it not applicable from a technical-operational point of view, in relation to the supports.

[0023] Further features and advantages of the invention will be recognisable by a person skilled in the art from the following detailed description of exemplary embodiments of the invention.

[0024] Brief Description of the Figures

[0025] For a better understanding of the following detailed description, some embodiments of the invention are illustrated in the accompanying drawings, wherein:

[0026] - Figures la and lb show frontally head portions of double-circuit supports with arrangement of the phases in symmetrical and anti-symmetrical configuration, according to the prior art,

[0027] - Figure 2a, 2b show frontally, respectively, a seven-phase support of the "Suspension" type with chains of "V" insulators, and an enlarged view of its head portion, for an overhead power line according to an embodiment of the invention,

[0028] - Figures 3 a, 3b show frontally, respectively, a seven-phase support of the type "Suspension with insulating shelf insulators" on the phases outside the vertices and with chains of "V" insulators on the central phase, for an overhead power line according to an embodiment of the invention,

[0029] - Figures 4a, 4b show frontally, respectively, a seven-phase support of the "Anchor" type and an enlarged view of its head portion, for an overhead power line according to an embodiment of the invention,

[0030] - Figures 5a, 5b show frontally, respectively, a seven-phase support of the " End of line-Portal" type and an enlarged view of its head portion, for an overhead power line according to an embodiment of the invention, - Figures 6a, 6b show frontally, respectively, a seven-phase support of the "End- of-line" type and an enlarged view of its head portion, for an overhead power line according to an embodiment of the invention,

[0031] - Figures 7a, 7b show frontally, respectively, a seven-phase support of the "Anchor" type, arranged for phase bundling, and an enlarged view of its head portion, for an overhead power line according to an embodiment of the invention,

[0032] - Figures 8a, 8b show frontally a seven-phase support of the "Passage anchor" type and an enlarged view of its head portion, in the event that the use of the seven phases takes place on a traditional line with double-circuit supports with an arrangement of the electrical phases of an anti-symmetrical type, for an overhead power line according to an embodiment of the invention,

[0033] - Figures 9a, 9b show frontally the same seven-phase support of the "Passage anchor" type and an enlarged view of its head portion, in the case, instead, in which the use of the seven phases takes place on a traditional line with double-circuit supports with an arrangement of the electrical phases of a symmetrical type, for an overhead power line according to an embodiment of the invention,

[0034] - Figure 10a schematically shows the geometric arrangement, in section, of the phases on the pole head of the seven-phase supports according to an embodiment of the invention,

[0035] - Figure 10b shows the hexagonal geometric arrangement of the electrical phases, arranged so that they lie, three by three, on the vertices of three equilateral triangles with a vertex in common corresponding to the central electrical phase of the third set and, mutually, in a broader sense, according to six equilateral triangles,

[0036] - Figure 10c shows the vertical geometric offset of the electrical phases, as well as of these with respect to the guard rope, of the seven-phase support according to the invention,

[0037] - Figures I la and 11b show perspective views of two embodiments of sevenphase supports according to the present invention, respectively, one of the single-shaft type and the other of the lattice type,

[0038] - Figures 12a and 12b show the schematic comparison between the head portions of double-circuit supports with arrangement of the phases in symmetrical and anti-symmetrical configuration, according to the prior art,

[0039] - Figures 13a and 13b show frontally two head portions of seven-phase supports of the present invention, of which the first with equal useful height (height of the lowest conductors above ground) of the double-circuit supports of the prior art, while the second, of the skyline type, i.e. such as to remain within the limits of visual occupation of the horizon, delineated by the original guard rope of the double-circuit supports (Figures 12a and 12b),

[0040] - Figures 14a and 14b show the graphs illustrating the comparison magnetic induction curves detected at the typical height from the ground equal to 1.5 m, as a function of the distance from the axis of the power line, for different types of power lines, with the same electric current transmitted, according to the prior art and according to some embodiments of the invention, as detailed below,

[0041] - Figure 15a shows the comparison between the magnetic induction iso-value curves (3 microtesla for Italian legislation) for three types of overhead power lines, distinguished by different electric current values, according to the prior art and some embodiments of the invention, as detailed below,

[0042] - Figure 15b shows the comparison of the ground electric field generated by different types of supports for overhead power lines with the same nominal voltage,

[0043] - Figures 15c and 15d show the comparison of radio disturbances and acoustic noise caused by the corona effect between seven-phase supports and conventional double-circuit supports,

[0044] - Figure 15e shows the comparison of the shielding angles between a sevenphase support and a traditional configuration,

[0045] - Figure 15f shows the comparison of the significant electrical circuits, for the purpose of defining the reverse discharge failure rate between a traditional doublecircuit support and a seven-phase support,

[0046] - Figure 15g shows the diagram relating to the significant electric currents for the purpose of defining the contact and step voltages,

[0047] - Figures 16a and 16b show the diagrams with the magnetic field flow lines generated respectively by a seven-phase power line according to the present invention and a double-circuit power line with anti-symmetrical phase arrangement,

[0048] - Figure 17 shows a graph representative of the maximum electrical power that can be transported by a power line as a function of its length, for three different types of overhead power lines according to the prior art and some embodiments of the invention, as detailed below,

[0049] - Figures 18a and 18b schematically show the mechanism of interaction with the birds, respectively, of a double-circuit support according to the prior art and of a seven-phase support according to an embodiment of the invention,

[0050] - Figures 19a and 19b schematically show the effects of interaction with the surrounding vegetation, respectively, of a double-circuit support according to the prior art and of a seven-phase support according to an embodiment of the invention,

[0051] - Figures 19c and 19d show the comparison of the constrained areas between power lines with conventional double-circuit supports and seven-phase supports,

[0052] - Figures 19e and 19f show the comparison between power lines with conventional double-circuit supports and seven-phase supports, in terms of the interaction of the overhead power line with respect to the mechanised work of the lands,

[0053] - Figure 20 shows a portion of a seven-phase overhead power line that departs from a portal of an electrical station, for example for sorting, and that develops on a piling made with the supports of the invention,

[0054] - Figures 20a-c show the same subject as Figure 20, where a respective set of homologous phases were individually represented for each Figure, with the different ascending solutions from the station portal to the support,

[0055] - Figure 21 shows a portion of an overhead power line according to an embodiment of the invention, in which there is a transition between double-circuit supports, with arrangement of the anti-symmetrical phases and seven-phase supports, by means of a support of "Passage anchor" type referred to in Figure 8a-8b,

[0056] - Figures 21a-c show the same subject as Figure 21, where a respective set of homologous phases have been isolated for each Figure, with the different attachment solutions on the supports,

[0057] - Figure 22 shows a portion of an overhead power line according to an embodiment of the invention, in which there is a transition between double-circuit supports, with arrangement of the symmetrical phases and seven-phase supports, through the same support of "Passage anchor" type referred to in Figure 9a-9b,

[0058] - Figures 22a-c show the same subject as Figure 22, where a respective set of homologous phases have been isolated for each Figure, with the different attachment solutions on the supports,

[0059] - Figure 23 shows the comparison between a seven-phase anchor support used for path angles up to 30° and a seven-phase anchor support for path angles between 30° and 60°. DETAILED DESCRIPTION

[0060] Subject-matter of the invention and general definitions

[0061] The subject-matter of the present invention is an overhead power line, indicated, overall, with the number 1 in Figures 20-22c, to be understood as a non-limiting example of the protection required.

[0062] The invention also relates to a method for renovating, in whole or in part, an overhead power line, illustrated by way of non-limiting example in Figures 21 -22c, which provides for starting from a pre-existing double-circuit power line and obtaining a power line 1 of the invention, replacing some components.

[0063] The power line 1, sometimes also referred to as an overhead electrical line, is known to comprise a plurality of supports 2 and a plurality of conductors, including phase conductors 3 and guard ropes 4.

[0064] The supports 2 are arranged in sequence along a direction of development of the power line 1. In this description, reference 2 is used to generically designate various types of supports, including seven-phase supports, generically indicated as 2a, and supports with different numbers of phases (six-phase double-circuit supports), generically indicated as 2b. Several examples of these supports will in turn be identified with references 2al, 2a2, 2a3, 2a4, 2a5, 2a6, 2a7, for the seven-phase supports 2a, and with references 2b 1, 2b2 for the six-phase double-circuit supports and with their symmetrical and anti-symmetrical arrangement, respectively. The details of these embodiments are illustrated later in the description.

[0065] The phase conductors 3, as well as the guard ropes 4, are supported by the supports 2 and develop, between the supports 2, along the direction of development of the power line 1. Some terminal components of the power line 1, for example a portal 6 of an electrical station, to which the phase conductors 3 and guard ropes 4 are connected, arranged before a first support 2 or after a last support 2 of the power line 1, for entry into the electrical stations at the two ends of the power line 1, can also be considered part of the power line 1.

[0066] The phase conductors 3, possibly grouped into bundles depending on the voltage level and the intensity of the electrical current to be transmitted, identify a plurality of electrical phases supported by the supports 2. As detailed below, references 31, 32, 33 will be used to generically designate sets of homologous phases, while the individual conductors or bundles of conductors belonging to such homologous phases will be individually indicated, for different examples of supports 2 and of power lines 1, with references 31a, 31b, 31b’, 31c, 32a, 32b, 32b’, 32c, 33, 33a, 33b.

[0067] In this description, the term phase is used to indicate a single-phase conductor 3 or a bundle of energized phase conductors 3, supported by the supports 2. More precisely, the term phase is used in accordance with the IEC 60050 dictionary (latest edition 2023). It defines that the term phase, for an alternating current line, designates any conductor 3 or bundle of conductors 3 intended to be energised during normal use. This distinguishes phase conductors 3 from other ropes not intended to be energized, such as the guard ropes 4 (seen in Figures 20-22c).

[0068] It is also clarified in the dictionary in question that a bundle of conductors is an assembly of individual conductors, connected in parallel to each other and arranged in a uniform geometric configuration, which constitutes a phase or a pole of an overhead electrical line. Therefore, if a phase is identified by several conductors 3, they are configured to be equipotential to each other.

[0069] Also in the same dictionary, it is indicated that for a polyphase system (or m- phase system) the phases are usually, but not necessarily, out of phase, and that the phase differences can also be equal to zero. This description contemplates both phases which are electrically isolated from each other, and therefore configured to be supplied with electrical quantities (voltage and current) that are generally out of phase with each other, and phases that are homologous to each other, that is, phases that, although physically distinct from each other, are configured to be equipotential, and between which, therefore, there is a substantially zero voltage offset. The equipotential condition can be obtained by means of electrical connections between the phase conductors 3 of the different phases involved, in the power line 1 or in other structures (not illustrated) located at the ends of the power line 1, such as electrical stations.

[0070] More in detail, the plurality of electrical phases identifies three sets of homologous phases which are a first set 31 (declined in 3 la, 3 lb, 31c), a second set 32 (declined in 32a, 32b, 32c) and a third set 33. The power line 1 is configured to be connected and powered by a common three-phase system (not illustrated), and precisely each set of homologous phases 31, 32, 33 of the power line 1 is configured to be electrically connected to a distinct phase of the three-phase system, commonly referred to as "R", "S" and "T". Thus, the electrical phases of each set 31, 32, 33 are configured to be electrically out of phase with respect to the electrical phases of the other sets, preferably for substantially 120° electrical phase-shifting angles.

[0071] As will be clear from the following, although the number of sets of homologous phases 31, 32, 33 is equal to three throughout the development of the power line 1, the number of the individual phases can be suitably varied along the aforesaid length of the power line 1 and, in particular, for different supports 2a and 2b. Preferably, throughout the description, when a number of phases or sets of phases 31, 32, 33 is indicated, it is meant an exact number, and not a minimum number of such elements. Description of the seven-phase supports

[0072] Each support 2, in a known manner, comprises a support portion 21 configured to be attached to the ground. The support portion 21 extends mainly vertically and is usually identified by a stem. Furthermore, each support 2 comprises a head portion 22 installable above and generally wider than the support portion 21.

[0073] In a lattice embodiment (Figures la-9b, 1 lb-13b and 18a-22c), the support portion 21 and the head portion 22 may be formed into the characteristic lattice shape. In a single-shaft embodiment (Figure I la), instead, an example of support 2a9 is provided in which the support portion 21 can be formed as a single tubular body, in particular with a polygonal, cylindrical or elliptical section, typically made of steel or reinforced concrete. In the following, several variants of seven-phase supports 2a are described mainly with reference to lattice embodiments, but they are also transferable to single-shaft type embodiments.

[0074] Each support 2 comprises a plurality of connecting attachments 5 configured to mechanically connect distinct electrical phases to the head portion 22.

[0075] Therefore, the number of connecting attachments 5 corresponds to the number of phases supported by the support 2. Reference 5 is used to indicate generically: the suspension attachment (visible in Figures 2a and 3a), the anchor attachments (perpendicular to the plane identified in Figures 4a, 5a, 6a, 7a, 8a, 9a), together with the corresponding recall chains (i.e. vertical insulator chains at the tip of the shelf for the external phases and "V" insulator chains in the central phase) that have the function of guiding the electrical connection (dead necks) upstream and downstream of the anchor for the conductors of homologous phases.

[0076] More precisely, as represented in Figures 4b, 5b, 6b, 7b, 8b, 9b, the connecting attachments are indicated with the following references: 51a, 51b, 51c, for the anchor and suspension connection points of the external phases,

[0077] 52 for the anchor and suspension connection points of the central phase,

[0078] 53 for the recall chains of the anchor supports, respectively for the external phases and the central phase.

[0079] Examples of suspension supports are indicated with reference numbers 2al, 2a2, while examples of anchor supports have references 2a3, 2a4, 2a5, 2a6 and 2a7. The details of these supports 2 are given individually below.

[0080] In particular, anchor supports comprise anchor connecting attachments arranged with fixed orientations with respect to the head portion 22 of the support, while suspension supports comprise suspension connecting attachments movably constrained to the head portion 22 of the support.

[0081] According to the invention, the plurality of supports 2 forming the power line comprises at least one seven-phase support 2a, preferably a plurality of seven-phase supports 2a. In particular, all the supports 2 of the power line 1 may be seven-phase supports 2a, or the power line 1 may comprise, in particular in the case of renovation, both seven-phase supports 2a, and supports 2 with a different number of phases, for example one or more reduced-phase supports 2b with a number of phases less than seven, typically three, five or six.

[0082] Each seven-phase support 2a, comprises seven connecting attachments 5 supporting seven respective electrical phases. Such connecting attachments 5 comprise six peripheral connecting attachments 51a, 51b, 51c and a central connecting attachment 52. The peripheral connecting attachments 51a, 51b, 51c are arranged so that the respective phases lie, in a projection on a vertical plane, at the vertices of a hexagon, preferably symmetrical with respect to a vertical plane, as well as more preferably a regular hexagon, so that the electrical phases come to be, three by three, on the vertices of three equilateral triangles having a vertex in common corresponding to the central electrical phase of the third set 33 and, mutually, in a broader sense, according to six equilateral triangles, (Figure 10b).

[0083] In the Figures in front view 5b (support of the "End of Line-Portal anchor" type) as well as 8b and 9b (support of the "Anchor passage" type) the positions of the phase conductors 3, supported by the support 2, are represented by circles with a solid or dashed line outline. The representation indicates, with the dashed circles, phase conductors 3 that start at the support 2 towards a subsequent support 2 located downstream. Conversely, the solid line circles designate phase conductors 3 connecting the illustrated support 2 to an upstream support 2, or a portal, (optionally also extending to the subsequent support).

[0084] In some Figures (8b, 9b), a circle with a solid line and a circle with a dashed line close to the same connecting attachment 5 represent a conductor phase 3 that assumes different positions: arriving from a support 2 or Portal 6 upstream (position of the circle with a solid line) and towards a support 2 downstream (position of the circle with a dashed line), the whole according to the metallic continuity of the connection guaranteed by the so-called "dead neck", indicated in the Figures with reference 54, of connection and relative recall chain 53.

[0085] In addition, different fill colours were used for the conductors of the three distinct sets of phases 31, 32, 33. In particular, for the first set of phases 31 a white filling of the circles was used (both in the case of continuous outline and dashed outline). For the second set of phases 32, a solid black filling was used, in the case of a continuous outline, and grey in the case of a dashed outline. For the phase of the third set 33 a diagonal line filling was used. The electrical phases of the first and second sets 31, 32 alternate along the perimeter of the hexagon, surrounding the phase of the third set 33, positioned in the centre.

[0086] Therefore, following the perimeter of the hexagon shown in Figures 10a and 10b, the phases 31a, 32a, 31c, 32b, 31b, 32c are met in the order, ensuring an arrangement such that each phase of one set is positioned between two phases of the other set.

[0087] For the purpose of balancing the electric currents in the phases, the phase of the third set 33 carries a triple current with respect to each of the three phases 3 la, 3 lb, 31c constituting the first set 31, and with respect to each of the three phases 32a, 32b, 32c constituting the second set 32. Thus, the phase of the third set 33 may include a greater number of conductors 3 and / or a conductor 3 of suitable section with a greater electric current flow rate.

[0088] For the purpose of the described arrangement of the connecting attachments 5, the head portion 22 of the support 2 has a perimeter body delimiting a central opening 23. The central connecting attachment 52 is placed in the central opening 23, through which the central phase 33 also extends.

[0089] In addition, according to a further aspect of the invention illustrated in Figure 10c, it is observed that the arrangement of the electrical phases of the first 3 la, 3 lb, 31c and of the second set 32a, 32b, 32c on the vertices of a hexagonal polygon of the sevenphase support 2a, and the appropriate arrangement of both the electrical phases of the third set 33a, 33b, 33c and of the guard ropes 4 allows obtaining the vertical offset of the electrical phases, as well as of these with respect to the guard rope 4, thus maintaining excellent ice-snow resilience characteristics, in relation to sleeve formation and detachment. In fact, in the event of the snow and / or ice sleeve formation on the electrical phases or on the guard rope 4, the relative lowering of these does not represent a critical element, in terms of reduction of the electrical clearance between the ropes and, consequently, allows the correct continuity of operation of the HV backbone. In this regard, it is important to point out that the hexagonal polygon geometry of the electrical phases 3 has been specially designed so that the relative offsets (Disl, Dis2, Dis3, Dis4) are greater than or equal to the minimum electrical insulation distances dictated by good technique, as a function of the nominal voltage value of the line. In particular, the intermediate electrical phases and the electrical phases of the third set 33a, 33b, 33c are vertically offset with respect to the upper and lower electrical phases, and the upper electrical phases are vertically offset with respect to the guard ropes 4.

[0090] Eight specific seven-phase supports 2a are now described, with reference to Figures 2a-9b. These supports have been designed to cover different uses required in a power line 1, so that the use of one or more types of supports 2 among these eight is sufficient to meet the typical path constraints and the needs of piling the route of a power line 1. They, therefore, allow an entire seven-phase power line 1 to be made, or a portion of a pre-existing power line to be renovated with seven-phase supports 2a.

[0091] A first seven-phase support 2al is illustrated in Figures 2a-2b. This is a "Suspension" support in which the connecting attachments 5 are identified by sets of insulators arranged in "V" chains. This support 2al is resilient from the point of view of good wind behaviour, in relation to the intrinsic mechanical stability of the attachments used.

[0092] Note that the intermediate peripheral phase conductors 31c and 32c and the central phase conductors 33 are vertically misaligned from the upper phase conductors 31a and 32a as well as the lower phase conductors 31b and 32b. This peculiarity gives the seven-phase support 2al a good ice-snow resilience, preventing ice sleeves or snow accumulations, due to the increased weight on the conductors, from causing the approach and the consequent electric discharge between different phases.

[0093] A second seven-phase support 2a2 is illustrated in Figures 3a-3b. It is also a " Suspension" support 2, but the connecting attachments 5 are of the "insulating shelves" type, that is, with chains of insulators arranged in an "L" shape. The use of these connecting attachments 5 makes it possible to keep the geometry of the head portion 22 particularly compact. Therefore, the visual interaction of the power line 1 is reduced and the good interaction with the birds is confirmed, to the advantage of the environmental sustainability of the technical solution. Also in this case, the design pursued and achieved the vertical misalignment of the separate phase conductors, which gives ice-snow resilience to the solution.

[0094] A third seven-phase support 2a3 is illustrated in Figures 4a-4b. It is an "Anchor" support, which can be positioned at portions of the path of the power line 1 that typically have angles of up to 30°. It guarantees a good compactness and a good phase offset of the conductors for a good ice-snow resilience.

[0095] A fourth seven-phase support 2a4 is illustrated in Figures 5a-5b. It is a support that will be referred to as an "End of Line-Portal" support and is provided with connecting attachments 5 of the anchor type. One of these "End of Line-Portal" supports, indicated 2a4, is used together with another identical support, always indicated with 2a4, for the connection of a portal 6 of an electrical station to other sevenphase supports 2a. The connection methods of the seven-phase power line 1 to the portal 6 are detailed in greater detail below with reference to Figures 20-20c.

[0096] The support 2a4 is similar in shape to the support 2a3, but with a different mechanical performance, due to the presence of two paired phases in the lower portion of the head 22. With reference to Figures 20-20c, it is noted that for the first support 2a4:

[0097] • the phase conductors of the lower section arrive in a paired configuration and remain as such even when departing towards the subsequent support 2a4;

[0098] • the phase conductors of the intermediate section are present only on the span between the supports 2a4, with appropriate bundlings 71 and 72 also visible in Figure 5b;

[0099] • the phase conductors of the upper part receive, instead, the conductor in a single configuration from the Portal 6 and continue, as such, towards the subsequent seven-phase supports;

[0100] Still with reference to Figures 20-20c, it is noted that for the second support 2a4:

[0101] • the phase conductors of the lower section arrive in a paired configuration from the previous support 2a4 and continue, in a single configuration, towards the subsequent seven-phase supports;

[0102] • the phase conductor of the intermediate section arrives in a single configuration from the previous support 2a4 and remains as such also on the next downstream span, continuing as such towards the subsequent seven-phase supports.

[0103] A fifth seven-phase support is indicated with 2a5 and is illustrated in Figures 6a-6b. It is a support provided with connecting attachments 5 of the anchor type that can be positioned at portions of the route of the power line 1 that typically have angles from 30° up to 60°. The support also has end-of-line performance typically by a few degrees of deviation of the incoming phases.

[0104] The support 2a5 is similar to the support 2a3, but with a different overall arrangement of the connecting attachments 5 in order to support the phase conductors 3 at appropriate positions to ensure the electrical distances between the phases according to the corner performance provided; in more detail, and with reference to Figure 23, it is observed that, compared to the supports 2a3, the seven-phase anchor support 2a5 has greater horizontal distances between the intermediate connecting attachments 51c.

[0105] A sixth seven-phase support, indicated as 2a6, is illustrated in Figures 7a- 7b. It is an anchor support 2, which can be positioned at portions of the route of the power line 1 having angles up to typically 30°. It is also specially designed to achieve the bundling of the phases, to be implemented with appropriate connection conductors 71 and 72 as shown in Figure 7b.

[0106] In particular, in the support 2a6 the phases are arranged at the vertices of an irregular hexagon since the median phase conductors have been widened on average while the upper phase conductors have been raised so as to allow the realization of the bundlings 71 and 72 (equipotential connections of the homologous phases) respecting the electrical safety distance of the other phases. Therefore, comparing the bundling support 2a6 with other seven-phase anchor supports, for example the support 2a3 with peripheral connecting attachments 51 arranged according to a regular hexagon, or the support 2a5, the distance in height between the two upper connecting attachments 51a and the two intermediate connecting attachments 51c is greater.

[0107] In particular, between two supports of the type 2a6, first bundling conductors 71 can be provided, which electrically connect together the phase conductors 31a, 31c 31b, of the first set of homologous phases 31, and second bundling conductors 72, which electrically connect together the phase conductors 32a, 32c, 32b, of the second set of homologous phases 32. A seventh seven-phase support, indicated as 2a7, is illustrated in Figures 8a, 8b and 9a, 9b; said support, of the "Passage anchor" 2a7 type, is used for the connection between double-circuit supports 2b and other seven-phase supports 2a. The methods of connection to the double-circuit supports 2b are more detailed below with reference to Figures 21 -21c in relation to an original double-circuit power line with antisymmetrical phase sequence, as well as Figures 22-22c in relation to an original doublecircuit power line with symmetrical phase sequence.

[0108] The support 2a7 is similar to the support 2a6, but with a different overall arrangement of the connecting attachments 5 in order to support the phase conductors 3 at appropriate positions for the connection, upstream, with a double-circuit support 2b, together with the corresponding different mechanical performance due to the absence, upstream, of some phase conductors.

[0109] As will be described below, the arrangement of the phases is different between the support of Figures 8a, 8b and that of Figures 9a, 9b, and this is because the same support 2a7 has been designed both to make a connection with the double-circuit support having an anti-symmetrical phase sequence 2b2, and to make a connection with the double-circuit support having a symmetrical phase sequence 2b 1.

[0110] The two different arrangements of the phase 3 are illustrated in detail in Figures 8b and 9b. In both Figures, in front view, some connecting attachments 5 are not illustrated as they are substantially perpendicular to the plane of the sheet.

[0111] In addition, comparing the passage anchor support 2a7 with other anchor sevenphase supports, for example the support 2a3, with peripheral connecting attachments 51 arranged according to a regular hexagon, or comparing it with the support 2a5, the distance in height between the two upper connecting attachments 51a and the two intermediate connecting attachments 51c is greater, to allow the appropriate bundling of the phases discussed later.

[0112] Advantages of using the seven-phase supports

[0113] To illustrate a series of advantages of the above-described conformation, Figures 14a-15d now illustrate the graphs comparing two different construction options of the preferred seven -phase support 2a, referred to herein as "equal useful height" options (height from the ground of the lowest conductors) and "skyline" (or equal height of the visual overall size of the guard rope of the double-circuit support), and other types of power lines, i.e. overhead lines with traditional six-phase double-circuit supports with symmetrical 2b 1 or anti-symmetrical 2b2 type phase sequence, as well as underground cable electrical line consisting of two circuits considered in the ideal condition of cloverleaf installation and optimized sequence of electrical phases.

[0114] In a traditional six-phase double-circuit suspension support 2b (Figures 12a, 12b), six connecting attachments support three pairs of homologous phases R-R’, S-S’ and T-T’; these connecting attachments, by analogy with the seven-phase support 2a, are numbered as peripheral connecting attachments 51a, 51b, 51c, even in the absence of central support structures 52.

[0115] Comparing, therefore, this arrangement with that of the seven-phase support 2a of the invention, i.e. by comparing Figures 12a-12b with Figure 13a (where the sevenphase support is represented in the condition of "equal useful height" of the doublecircuit support), with equal electrical voltage and, therefore, insulation required, the head portion 22 of the seven-phase support 2a was designed to pursue total height dimensions smaller than the head portion 22 of the double-circuit support 2b.

[0116] This peculiarity, achieved through a specific design of the head-pole geometry, allows to decrease the visual interaction of the seven-phase support 2a compared to a conventional type power line with double-circuit support 2b. The same specific design, according to the skyline option (Figure 13b), i.e. the one for which the overall height of the seven-phase support 2a reaches that of the two double-circuit supports 2b 1, 2b2 (at the level of the guard rope 4), allows, with the same total height (and therefore visual interaction), an increase in the electrical safety distance from the ground (increase in height equal to AH) and, consequently, a reduction in the magnetic field present at ground level.

[0117] In this regard, Figure 14a shows the magnetic induction generated at a height of 1.5 m from the ground as a function of the lateral distance from the power line axis 1, for the two different types of supports of the known art, in double-circuit, with symmetrical and anti-symmetrical arrangement of the phases 2b 1, 2b2, highlighting how the anti-symmetrical arrangement 2b2 allows to detect, between the two solutions under examination, a lower value of magnetic induction.

[0118] Figure 14b, on the other hand, shows the comparison between the best solution in terms of containment of the magnetic induction of the known art (i.e. double-circuit with arrangement of the anti-symmetrical phases 2b2) generated at a height of 1.5 m from the ground as a function of the lateral distance from the power line axis 1, with two solutions of seven-phase support 2a in the version "with the same useful height" and according to the "skyline" option, and with a double-circuit power line with underground cable, although considered in the ideal condition of cloverleaf installation and optimised sequence of the electrical phases.

[0119] Therefore, from top to bottom, the magnetic induction curves represented concern the following types of power line, namely:

[0120] - overhead double-circuit power line with anti-symmetrical phases 2b2, - seven-phase power line 2a, in "equal useful height" configuration,

[0121] - seven-phase power line 2a, in "skyline" configuration,

[0122] - underground cable consisting of two double circuits, considered in the ideal condition of cloverleaf installation and optimised sequence of electrical phases.

[0123] Figure 14b highlights how the seven-phase supports 2a allow, with the same electric current and electric power transmitted by the power line 1, a substantial reduction in the magnetic induction field compared to the best of the solutions of the prior art, already in the "same useful height" condition and even more significantly in the condition of equal total height ("skyline" option).

[0124] With the latter condition, the maximum value of the magnetic induction field becomes even lower than the quality objective of 3 pT (Italian legislation) for all distances from the line axis and, even, comparable with that of an underground cable power line.

[0125] Figure 15a shows, on the other hand, the iso-field curves at 3 pT for different electric current values and different types of supports 2, with the same electric voltage. It is functional for technical evaluations aimed at a possible use of the seven-phase supports 2a for the modernization of existing conventional type power lines 2b, with specific reference to the so-called "magnetic imprint" on the territory, to be understood as a projection on the ground of the aforementioned iso-field curve at 3 pT.

[0126] In particular, the iso-field curves represented refer to the following types of power line, considered with different electric currents:

[0127] - double-circuit power line with anti-symmetrical phases 2b2, referring to a characteristic value of electric current II (current flow rate in normal service, according to the Italian standard),

[0128] - seven-phase power line 2a, in "equal useful height" configuration, referring to an electric current, 12, more than doubled compared to II,

[0129] - seven-phase power line 2a, in "skyline" configuration, with the same electrical current 12 of the previous curve, more than doubled compared to II.

[0130] The comparison between the iso-field curves of Figure 15a shows that, thanks to the "confinement" effect of the magnetic field produced by the invention, as better described in Figure 16a, through the use of the seven-phase supports 2a, the iso-field curves have a narrow and elongated shape upwards so that their projection on the ground is reduced (magnetic imprint of the power line 1), thus reducing the occupation of the territory.

[0131] This peculiarity is found even if the power line with seven-phase supports 2a was considered in the calculation with an electric current 12 more than double the electric current II of the conventional double-circuit power line 2b. These benefits are further improved, in terms of reducing the magnetic induction value at ground level, for the supports 2a in the "skyline" option.

[0132] To better explain how the particular geometry of the seven-phase supports 2a allows the aforementioned performance, in terms of reduction of magnetic induction, Figures 16a and 16b show the magnetic field flow lines in the cases of seven-phase support 2a (Figure 16a) and double-circuit support 2b (Figure 16b). As can be seen, in the case of the seven-phase support 2a, the flow lines of the magnetic field are characterized by a "confinement" effect within the hexagon geometry defined by the phase conductors 3 while, in the double-circuit support 2b, their dispersion is observed horizontally, with a consequent greater projection ("magnetic imprint") on the ground.

[0133] The advantageous effects described are maximum in the event that the phase conductors 3 correspond exactly to the vertices of a regular hexagon which, in this case, are very likely for the suspension supports 2a; however, limited displacements with respect to the positions of the vertices of a regular hexagon are permissible without losing the aforementioned advantageous effects as occurs in the support 2a6 of the "Anchor" type, set up for phase bundling.

[0134] The seven-phase support 2a also brings advantages under other profiles, in addition to that of the magnetic field.

[0135] In particular, as can be seen in Figure 15b, at the same nominal voltage of the power line 1, the ground electric field generated by a seven-phase support 2a in the "at the same useful height" option is comparable to that of a double-circuit support 2b, while for a seven -phase support 2a in the "skyline" option it has much lower peak values.

[0136] In addition to this, and with reference to Figures 15c and 15d, the seven-phase support allows, compared to a conventional double-circuit support, a decrease respectively in radio disturbance (Figure 15c) and acoustic noise (Figure 15d) which are caused by the corona effect, both in the option "with the same useful height" and, even more markedly, in the case of the "skyline" option.

[0137] In electrical terms, it is further observed that the seven-phase support also allows an improvement in lightning strike performance compared to a conventional doublecircuit power line. As is known, in fact, the guard ropes, to ensure effective shielding, must be arranged so as to form a reduced coverage angle (less than or equal to 30°) and then intercept the lightning, before they strike the conductors.

[0138] As can be seen in Figure 15e, the seven-phase support 2a, thanks to the described geometry of the head-pole 22 and the presence of two guard ropes 4, guarantees lower shielding angles (much less than 30°) than the traditional doublecircuit configuration 2b, thus reducing the likelihood of a failure due to direct lightning strike of the conductors. The construction shape of the head 22 of the seven-phase support 2a, together with the aforementioned presence of two guard ropes 4, reduces the impedance equivalent to lightning strike of the circuit comprising the guard ropes 4, compared to a conventional double-circuit power line 2b (Figure 15f). Therefore, in case of lightning strike of the support 2 or the guard ropes 4, the overvoltage produced by the lightning strike is lower: e ?F (t) < and DT ( / ); therefore, the risk of reverse discharges, therefore the failure rate due to lightning strike, of a seven-phase support 2a is reduced compared to a conventional double-circuit power line 2b. The improvement in performance after lightning strike, already significant for the "skyline" support option, is even more pronounced for the support option "with the same useful height", since the total height of the seven-phase support is less than the traditional double-circuit one.

[0139] As illustrated in Figure 15f, the seven-phase support 2a therefore reduces the reverse discharge failure rate thanks to two advantages:

[0140] Greater number of guard ropes and therefore lower equivalent wave impedance Zfdgof the same: having twice the number of guard ropes, the overall equivalent wave impedance tends to halve compared to a traditional double-circuit stem support 2b.

[0141] - Lower ZT wave impedance of the tower itself, thanks to the particular geometry of the head, which provides a reduction by about 21%.

[0142] Consequently, at the same current i(t) injected by the lightning on the line towards the ground, the greater electric current drained by the guard ropes, due to their overall lower equivalent wave impedance Zfdg / 2, determines a greater electric current drained by the guard ropes and a consequent lower electric current drained by the pole towards the ground which, together with the lower wave impedance ZT (ZT 7F < ZT DT), determines a reduction by about 12% of the voltage e(f). This makes the seven-phase support 2a a very resilient solution to extreme weather events, caused by ongoing global climate change.

[0143] As is known, the use of a pole head provided with guard ropes, allows, in the event of in-line failure, also the containment of the magnitude of the contact (UT) and step voltages (Us) and, therefore, the reduction of the risk of electrocution, as illustrated in Figure 15g, towards third parties. In fact, the guard ropes drain part of the failure electric current, reducing the portion of electric current that must be drained from the ground system of the support.

[0144] The seven-phase support 2a, having double the guard ropes compared to a traditional double-circuit support 2b, allows a significant reduction in the electrical current drained to the ground and, therefore, in the corresponding contact (UT) and step (Us) voltages. This advantage is particularly relevant with regard to the use, with greater security vis-a-vis third parties, of the new seven-phase supports in anthropized contexts.

[0145] For example, in an area of high resistivity (Rearth=20 Ohm, Ifaiiure=16 kA) the earth current of the seven-phase support 2a is at least 30% lower than that of the traditional double-circuit support 2b.

[0146] Another advantage of the present invention is related to the lower service electrical reactance of a power line made with seven-phase supports 2a compared to a conventional electrical power line consisting of double-circuit supports 2b. As is known, in fact, the service electrical reactance of a power line 1 determines its maximum transmittable electrical power for compliance with the voltage drop and angular phase shift constraints between the departing and arriving electrical voltages of the electrical line of a given length. A power line 1 made with seven-phase supports 2a allows to transmit, for example for an overhead power line of 220 kV and lengths up to 150 km, and with the same angular stability constraints, electrical powers equal to 1.5 times those of a conventional double-circuit power line 2b. This is illustrated in Figure 17, where the maximum transmittable power between the ends of the power line 1 is reported for the options of overhead line with traditional double-circuit supports 2b, overhead line with seven-phase supports 2a and overhead line with seven-phase supports 2a and the addition of the series compensation.

[0147] Another advantageous aspect of the present invention relates to its sustainability, both environmental and social. On the environmental front, the invention implies an improvement in interactions with the birds and with the surrounding vegetation. Instead, in terms of social sustainability, the invention allows the wide compliance with safety distances (provided for by current regulations) for the preexisting power line 1 while reducing the interaction on mechanized agricultural processing and forestry activities.

[0148] In more detail, as illustrated for comparison in Figures 18a, 18b, compared to conventional double-circuit supports 2b, the seven-phase supports 2a have a reduced vertical distance of the guard ropes 4 from the conductors of the high phases 3 (h2 < hl), with the same height of the same. This implies an excellent behaviour of the support of the overhead line in the presence of birds, reducing the risks of impact with the guard rope 4, considering that, typically, birds deviate upwards (perceiving the corona effect thereof) when they approach a live conductor phase 3 laterally, thus risking interacting, by impact, with the guard rope 4.

[0149] The other environmental sustainability advantage of the seven-phase supports 2a is given by the lower overall size of the low electrical phases (d2 < dl), compared to the conventional double-circuit supports 2b, as well as a shorter swing length of the catenary-isolator system (L2 < LI), since the "V" chains of the isolators of the sevenphase support are not involved in the oscillation of the aforementioned system, as is the case for the conventional double-circuit ones 2b. All this, as depicted in Figures 19a and 19b, shows that the new seven -phase supports 2a of the invention have a lesser interaction with the vegetation present than those of the traditional double-circuit supports 2b of the known art. In detail, with the use of the seven-phase supports 2a that allow the "skyline" type option to be adopted (Figure 19b), the aforementioned lower electrical phases are located at a greater height from the ground than the traditional double-circuit solution 2b (Figure 19a) and, consequently, even in the event of oscillation, they interact less with the surrounding vegetation.

[0150] As mentioned, also in terms of social interaction, the invention is very advantageous, as there is no increase in the characteristic constrained area of the power line (notoriously defined by current regulation / legi slation on overhead electrical lines) which takes into account the adoption of compliance with specific constraint distances (dl and d2) referable, respectively, to the condition of vertical catenary and inclined catenary due to the oscillation by effect of the wind, as shown in Figures 19c and 19d.

[0151] It is observed, specifically, that the constrained area FADT of a conventional double-circuit power line 2b (Figure 19d), which is equal to twice the half-area FAi, is greater than the constrained area FA?F of a seven-phase power line 2 (also equal to twice the half-area FA2); this by virtue of a more compact pole head, in width (D2 < Dl), as well as the adoption for the seven-phase support 2a, of an attachment of the insulators that avoids the oscillation contribution to the catenary (L2 < LI).

[0152] In other words, the renovation of an existing conventional double-circuit power line 2b, according to the innovative seven-phase 2a invention, not resulting in increases in the existing constrained area, allows the social acceptability of the intervention to be pursued immediately. Description of the power lines made with the seven-phase supports

[0153] Some embodiments of overhead power lines 1 made partially or completely with seven-phase supports 2a and illustrated in Figures 20 to 22c are now described, so as to take into account all its possible uses both for the construction of new overhead lines, and for the modification of existing overhead power lines.

[0154] With reference to Figure 20, the power line 1 comprises, at one or both of its ends, a portal 6 of an electrical station, consisting of two towers 61 and a connecting beam 62 mounted between the two towers 61, configured to support electrical phases of the first, second and third set of phases 31, 32, 33.

[0155] In one embodiment, the first support 2 of the power line 1, i.e. the support 2 proximal to the portal 6, is already a seven-phase support 2a, in particular a seven-phase support of the End of Line-Portal type 2a4.

[0156] In this embodiment, as shown in Figures 20-20c, two End of Line-Portal supports 2a4 are present in sequence along the power line 1, after the portal 6, and, in addition, also one or more seven-phase suspension supports 2a (in the example illustrated they are type 2al supports, but type 2a2 suspension supports could also be used).

[0157] The function of the two End of Line-Portal supports 2a4 is to allow, as better described below, the exit and entry of the seven-phase overhead electrical line in the respective end power stations.

[0158] In fact, while in Figure 20 all the electrical phases of a portion of the power line 1 are represented, in Figures 20a-20c partial views of the same portion of power line are shown, in which only the phases of the third set 33, only the phases of the first set 31 and only the phases of the second set 32 are illustrated, respectively.

[0159] For the third set 33 (Figure 20a), it is easily noted that a single phase connects the beam 62 of the portal 6 and the central connecting attachments 52 of each of the two End of Line-Portal supports 2a4 and of each subsequent seven-phase suspension support 2a. The conductors 3 supported by the central connecting attachment 52 are tripled in that they are equivalent to those of a peripheral set.

[0160] For the first set 31 (Figure 20b), one of the phases, the one indicated with 31a, connects the beam 62 of the portal 6 and one of the upper connecting attachments 51a of each of the two End of Line-Portal supports 2a4 and of each subsequent seven-phase suspension support 2a.

[0161] Another of the phases of the first set, indicated with 3 lb, connects the beam 62 of the portal 6 and one of the lower connecting attachments 5 lb of each of the two End of Line-Portal supports 2a4 and of each subsequent seven-phase suspension support 2a. This phase 3 lb is partially separated, that is, there is a parallel phase 3 lb’ which is fixed to the same lower connecting attachment 51b of each of the two End of Line-Portal supports 2a4, as well as to the beam 62 of the portal 6, without however extending as far as the subsequent seven-phase suspension supports 2a. This parallel phase 31b’, therefore, ends at the second End of Line-Portal support 2a4.

[0162] The aforementioned parallel phase 3 lb’ is configured to electrically connect the phase 31c arranged between the intermediate connecting attachments 51c of each of the two End of Line-Portal supports 2a4, and then continue in the subsequent seven-phase suspension supports 2a, without therefore extending as far as the portal 6 and the corresponding beam 62. Therefore, for the purposes of its supply, there is at least one first bundling conductor 71, positioned so as to electrically connect it with the aforementioned parallel phase 31b’ between the two End of Line-Portal supports 2a4.

[0163] Finally, for the second set 32 (Figure 20c), the arrangement of the phases is dual with respect to those of the first set 31. Therefore, the following is only briefly described for this set 32, it being understood that what has already been illustrated for the first set 31 applies by analogy.

[0164] In particular, one of the phases indicated with 32a connects the beam 62 of the portal 6 and one of the upper connecting attachments 51a of each of the two End of Line-Portal supports 2a4 and of each subsequent seven-phase suspension support 2a.

[0165] Another of the phases of the second set, indicated with 32b, connects the beam 62 of the portal 6 and one of the lower connecting attachments 51b of each of the two End of Line-Portal supports 2a4 and of each subsequent seven-phase suspension support 2a. This phase 32b is partially separated, by means of a parallel phase 32b’ that ends at the second End of Line-Portal support 2a4.

[0166] The aforementioned parallel phase 32b’ is configured to electrically connect the phase 32c arranged between the intermediate connecting attachments 51c of each of the two End of Line-Portal supports 2a4, and then continue in the subsequent seven-phase suspension supports 2a, without therefore extending as far as the portal 6 and the corresponding beam 62. Therefore, for the purposes of its supply, there is at least a second bundling conductor 72, positioned so as to electrically connect it with the aforementioned parallel phase 32b’ between the two End of Line-Portal supports 2a4.

[0167] With reference to Figures 21 and 22, portions of a power line 1 are illustrated having six-phase double-circuit supports, respectively with an arrangement of the antisymmetrical 2b2 and symmetrical 2b 1 phases, and supports of the "Passage anchor" 2a7 type to make the transition from the aforementioned conventional overhead line to a portion of the line with seven-phase supports 2a, according to the invention.

[0168] In Figures 21a-21c and 22a-22c these embodiments are repeated highlighting for each figure the different sets of homologous phases 31, 32, 33 for the seven-phase supports 2a7 and 2a, as well as the sets of homologous phases R-R’, S-S’, T-T’ for the corresponding six-phase double-circuit supports, respectively 2b2 and 2b 1.

[0169] It can be seen how the support of the invention called "Passage anchor" 2a7 can be used both in the hypothesis that upstream there is a conventional double-circuit support with anti-symmetrical arrangement 2b2 of the phases, and a conventional double-circuit support with symmetrical arrangement 2b 1. A technician in the sector, possibly modifying the geometry of the support 2a7, may similarly use a special passage support to connect a section of upstream power line, with single-circuit supports, with a section of downstream power line, with seven-phase supports 2a.

[0170] Returning to the case of transition from seven-phase double-circuit, for the third set of phases 33 (Figures 21a and 22a), both in the anti-symmetrical solution 2b2 and in the symmetrical solution 2b 1, the phases indicated with S and S’ connect each double-circuit support 2b, and in particular one of its intermediate connection (suspension) attachments 51c, with the central connecting attachments 52 of each subsequent passage support 2a7 and of each seven-phase suspension support 2a.

[0171] In this case, therefore, the two phases S, S’ converge from the intermediate connecting (suspension) attachments 51c of the double-circuit support 2b to the central connecting attachment 52 of the passage support 2a7.

[0172] For the first and second set of phases T-T’, R-R’ (Figures 21b, 21c, 22b, 22c) the phases are arranged differently in the case of anti-symmetrical 2b2 and symmetrical 2b 1 double circuit.

[0173] We now proceed to the description of the arrangement of the phases for the conventional double-circuit support with configuration of the phases of the antisymmetrical type 2b2.

[0174] With regard to the first set T-T’, illustrated in Figure 21b: a phase T connects an upper connecting (suspension) attachment 51 a of the double-circuit support 2b2, with the intermediate connecting attachments 51c of the support of "Passage anchor" type 2a7 and of each subsequent seven-phase suspension support 2a, being identified with phase 31c of the first set 31 ; a phase T’ connects the lower connecting (suspension) attachments 51b of the double-circuit support 2b2, with the lower connecting attachments 51b of the support of "Passage anchor" 2a7 type and each subsequent sevenphase suspension support 2a, being identified with phase 3 lb of the first set 31.

[0175] The remaining phase 31a of the first set 31 connects upper connecting attachments 51a of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2al, without being mechanically connected with the double-circuit support 2b2. Since this phase 31a does not reach the previous (or any subsequent) conventional double-circuit support 2b, for the purpose of its energization and balancing of electric currents between homologous phases of the seven-phase line section, a first bundling conductor 71 electrically connects phases 31b and 31c with 31a, that is, connects all the phases of the first set 31 to each other.

[0176] As for the second set R-R’, visible in Figure 21c: a phase T connects an upper connecting (suspension) attachment 51 a of the double-circuit support 2b2, with the intermediate connecting attachments 51c of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2a, being identified with phase 32c of the second set 32; a phase R connects the lower connecting (suspension) attachments 51b of the double-circuit support 2b2, with the lower connecting attachments 51b of the support of "Passage anchor" 2a7 type and of each subsequent sevenphase suspension support 2a, being identified with phase 32b of the second set 32.

[0177] The remaining phase 32a of the second set 32 connects upper connecting attachments 51a of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2a, without being mechanically connected with the double-circuit support 2b2. Similarly, since this phase 32a does not reach the previous (or any subsequent) conventional double-circuit support 2b, in order to power it and balance electric currents between homologous phases of the seven-phase line section, a second bundling conductor 72 is configured to electrically connect phases 32b and 32c with 32a, i.e. connect all the phases of the second set 32 together.

[0178] We now proceed to the description of the arrangement of the phases for the conventional double-circuit support with symmetrical configuration of the phases 2b 1.

[0179] With regard to the first set T-T’, illustrated in Figure 22b: a phase T connects a lower connecting (suspension) attachment 51b of the double-circuit support 2b 1, with the intermediate connecting attachments 51c of the support of "Passage anchor" 2a7 type and each subsequent sevenphase suspension support 2a, being identified with phase 31c of the first set 31; a phase T’ connects the lower connecting (suspension) attachments 51b of the double-circuit support 2b 1, with the lower connecting attachments 51b of the support of "Passage anchor" 2a7 type and of each subsequent sevenphase suspension support 2a, being identified with phase 3 lb of the first set 31. The remaining phase 31a of the first set 31 connects the upper connecting attachments 51a of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2al, without being mechanically connected with the double-circuit support 2b 1. Since this phase 31a does not reach the previous (or any subsequent) conventional double-circuit support 2b 1, for the purpose of its energization and balancing of electric currents between homologous phases of the seven-phase line section, a first bundling conductor 71 electrically connects phases 31b and 31c with phase 3 la, i.e. connects all the phases of the first set 31 to each other.

[0180] As for the second set R-R’, visible in Figure 22c: a phase R’ connects an upper connecting (suspension) attachment 51a of each double-circuit support 2b 1, with the intermediate connecting attachments 51c of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2a, being identified with phase 32c of the second set 32; an R phase connects the upper connecting (suspension) attachments 51a of each double-circuit support 2b 1, with the upper connecting attachments of the support of "Passage anchor" 2a7 type and each subsequent seven-phase suspension support 2a, being identified with phase 32a of the second set 32.

[0181] The remaining phase 32b of the second set 32 connects lower connecting attachments 51b of the support of "Passage anchor" 2a7 type and of each subsequent seven-phase suspension support 2a, without being mechanically connected with the double-circuit support 2b 1. Similarly, since this phase 32b does not reach the previous (or any subsequent) conventional double-circuit support 2b 1, for the purpose of its energization and balancing of electric currents between homologous phases of the seven-phase line section, a second bundling conductor 72 is configured to electrically connect phases 32a and 32c with phase 32b, i.e. connect all the phases of the second set 32 together.

[0182] In order to be able to manage, from a point of view of respecting the electrical distances between different phases, the possibility of making the transition from a double-circuit power line (both with symmetrical and anti-symmetrical phases) to a seven-phase support, and therefore to be able to put the conductors in the equipotential condition, it was ensured, in the passage support 2a7, to have a suitable geometry of the equipotential connections 71 and 72, raising, compared to the typical "Anchor" pole 2a3, the conductors of the phases on the high shelves and preparing a diversified "forward-backward" connection of the median phases, as evident from Figures 8b and 9b.

[0183] Figures 21 -22c also show a guard rope 4 that splits in two, by a "dovetail" solution, identified with reference 73, between one or more double-circuit supports 2b and the passage support 2a7, and then proceed along the section with seven-phase supports 2a.

[0184] From what has been described so far with reference to Figures 21 -22c, it can be noted that, both in the case of symmetrical double-circuit, and anti-symmetrical doublecircuit, sets of homologous phases R-R’, S-S’, T-T’ coming from one or more doublecircuit supports 2b, are connected, at the passage support 2a7, respectively with at least one electrical phase of the first set 31, at least one electrical phase of the second set 32 and at least one electrical phase of the third set 33, coming from a seven -phase support 2a adjacent to the passage support 2a7. Furthermore, at least one electrical phase for each of the first and second sets 31, 32 has one end connected to the passage support 2a7, and connects the same with the adjacent seven-phase support 2a, without being mechanically connected with the double-circuit support 2b. It should be noted that all the above arrangements for the individual phases, for the purposes of connection to the terminal structures 6 and for the purposes of the transition between double-circuit supports 2b and seven-phase supports 2a (and vice versa), are to be understood only as a preferred embodiment example, but a technician in the field could identify alternative provisions and arrangements for these purposes.

[0185] Finally, a method for renovating, in whole or in part, an overhead power line with conventional double-circuit supports 2b, preferably six-phase symmetrical 2b 1 or anti-symmetrical 2b2 double circuit, in order to obtain a power line 1 with one or more seven-phase supports 2a as described so far is described. The method therefore provides for replacing one or more six-phase double-circuit supports 2b with one or more sevenphase supports 2a.

[0186] The substitute seven-phase supports 2a can be of the "same useful height" or "skyline" type, therefore selected with extensions in height that correspond to what has already been described in comparison with the double-circuit supports 2b.

[0187] Following the aforementioned replacement, it will be possible to obtain an overhead power line with superior performance, namely:

[0188] - with the same electrical current and electrical power transmitted, a reduction in the magnetic field produced by the overhead electrical line and, therefore, the possibility of the overhead electrical line thus renovated coexisting with any anthropized areas,

[0189] - with equal occupation of the territory dictated by the magnetic field produced by the original overhead electrical line (magnetic imprint), the possibility of transmitting a greater current and electrical power, enabling the energy transition process (characterized by greater transmitted electrical powers) on the infrastructural electrical corridors present in the territory.

Claims

1. CLAIMS1. Overhead power line (1), comprising:- a plurality of supports (2), and- a plurality of electrical phases supported by the supports (2), wherein:- each electrical phase is identified by a phase conductor (3), or a bundle of phase conductors (3),- the plurality of electrical phases identifies three sets of homologous phases (31, 32, 33), which are a first set (31), a second set (32) and a third set (33), wherein the electrical phases of each set (31, 32, 33) are configured to be equipotential to each other and electrically out of phase with the electrical phases of the other sets (31, 32, 33),- each support (2) comprises a support portion (21) configured to be attached to the ground, a head portion (22) formed over the support portion (21), and a plurality of connecting attachments (5) configured to connect distinct electrical phases (3) to the head portion (22), characterised in that:- the plurality of supports (2) comprises one or more seven-phase supports (2a), each having seven connecting attachments (5) supporting seven respective electrical phases (3),- the connecting attachments (5) of each seven-phase support (2a) comprising one central connecting attachment (52) and six peripheral connecting attachments (51), the peripheral connecting attachments (51) being arranged so that their respective electrical phases (3) are located, in a projection on a vertical plane, at the vertices of a hexagonal polygon, and comprising two upper connecting attachments (51a), two lower connecting attachments (51b), and two intermediate connecting attachments (51c), thecentral connecting attachment (52) being arranged within the hexagonal polygon;- the six peripheral connecting attachments (51) support six electrical phases (3), which are three electrical phases of the first set (31a, 31b, 31c) and three electrical phases of the second set (32a, 32b, 32c), the electrical phases of the first and second sets (31a, 32a, 31c, 32b, 31b, 32c) connected to the peripheral connecting attachments (51) are arranged alternately on the vertices of the hexagonal polygon and around the central connecting attachment (52), and- the central connecting attachment (52) supports at least one electrical phase of the third set (33).

2. Power line (1) according to claim 1, wherein:- the hexagonal polygon is a regular polygon, preferably a regular hexagon, and the central connecting attachment (52) supports an electrical phase of the third set (33) placed substantially in the geometric centre of the regular hexagon.

3. Power line (1) according to claim 1 or 2, wherein:- two high phases (31a, 32a) of the first and second sets are supported by their respective upper connecting attachments (51a) and are horizontally placed alongside each other, thus defining an upper side of the hexagonal polygon,- two lower phases (31b, 32b) of the first and second sets are supported by their respective lower connecting attachments (51b) and are horizontally placed alongside each other, thus defining a lower side of the hexagonal polygon.

4. Power line (1) according to any one of claims 1 to 3, wherein:- the electrical phases (31a, 32a, 33) (31c, 32b, 33) (31b, 32c, 33) are arranged so thatthey lie, three by three, on the vertices of three equilateral triangles with a vertex in common corresponding to the central electrical phase of the third set (33) and, mutually, according to six equilateral triangles with common sides.

5. Power line (1) according to any one of claims 1 to 4, wherein:- the head portion (22) has a perimeter body delimiting a central opening (23),- the central connecting attachment (52) is placed in the central opening (23), and- the peripheral connecting attachments (5) are placed outside the perimeter body, on two opposite sides of the perimeter body.

6. Power line (1) according to any one of claims 1 to 5, comprising, in sequence along the power line (1):- one or more double-circuit supports (2b), preferably six-phase supports of the doublecircuit type, or single-circuit three-phase supports,- a seven-phase anchor support (2a), which is a passage support (2a7).

7. Power line (1) according to claim 6, wherein:- sets of homologous phases (R-R1, S-S', T-T') from one or more double-circuit (2b), or single-circuit supports are connected at the passage support (2a7), respectively with at least one electrical phase of the first set (31), at least one electrical phase of the second set (32) and at least one electrical phase of the third set (33), coming from a sevenphase support (2a) adjacent to the passage support (2a7),- at least one electrical phase for each of the first and second sets (31, 32) has one end connected to the passage support (2a7), and connects it with the adjacent seven-phase support (2a), without being mechanically connected to the double-circuit support (2b)or single-circuit support,- wherein at least one first bundling conductor (71) electrically connects all the electrical phases of the first set (31a, 31b, 31c) between the passage support (2a7) and the adjacent seven-phase support (2a) with each other, and wherein at least one second bundling conductor (72) electrically connects all the electrical phases of the second set (32a, 32b, 32c) between the passage support (2a7) and the adjacent seven-phase support (2a) with each other.

8. Power line (1) according to claim 6 or 7, wherein a distance in height between the two upper connecting attachments (51a) and the two intermediate connecting attachments (51 c) is greater for the passage anchor support (2a7) than at least one sevenphase anchor support (2a3) of the power line (1) with peripheral connecting attachments (51) arranged according to a regular hexagon.

9. Power line (1) according to any one of claims 1 to 8, wherein, along a section of the power line, a seven-phase bundling anchor support (2a6) has a distance in height, between the two upper connecting attachments (51a) and the two intermediate connecting attachments (51c) that is greater compared to at least one seven-phase anchor support (2a3) of the power line (1) with peripheral connecting attachments (51) arranged in a regular hexagon, so as to allow creating the bundlings (71, 72) adapted to provide equipotentiality of the homologous phases, respecting the electrical safety distance of the other phases.

10. Power line (1) according to any one of claims 1 to 9, comprising:- a first seven-phase anchor support (2a3) at a section of the power line with a pathangle of up to 30°, and- a second seven-phase anchor support (2a5) at a section of the power line with a path angle between 30° and 60°; wherein said second seven-phase anchor support (2a5) has larger horizontal distances between the intermediate connecting attachments (51c) than said first seven-phase anchor support (2a3), in order to support the phase conductors at appropriate positions and to ensure the electrical distances between the phases according to the angle performance provided.

11. Power line (1) according to any one of claims 6 to 8, comprising a guard rope (4) that splits in two, by a "dovetail" solution (73), between one or more double-circuit supports (2b) and the passage support (2a7), and then proceeds in parallel with each other along the subsequent seven-phase supports (2a).

12. Power line (1) according to any one of claims 1 to 11, comprising, in sequence along the power line (1):- a portal (6) configured to support electrical phases of the first, second and third set (31, 32, 33),- one or more seven-phase anchor supports (2a) that are supports of the End of line- Portal (2a4) type, preferably two End of line-Portal (2a4) type supports, and- one or more successive seven-phase supports (2a).

13. Method for renovating a six-phase double-circuit overhead power line, comprising, for a seven-phase intervention section, the replacement of one or more six-phase double-circuit supports (2b) with one or more seven-phase supports (2a), resulting inan overhead power line (1) according to any one of claims 1 to 12, wherein the seven-phase supports (2a) have:- an overall height lower than or equal to the six-phase supports (2b),- a useful height equal to or greater than that of the six-phase double-phase supports (2b), wherein the useful height is the height of the lowest conductors above the ground, and- a head portion (22) that has both a height dimension and a width dimension of the head (22) lower than those of a head of the six-phase double-circuit supports (2b).

14. Renovation method according to claim 13, wherein a downward facing shielding angle, formed with respect to the vertical between a guard rope (4) and an adjacent upper connecting attachment (51a), is lower for each seven-phase support (2a) than for each six-phase double-circuit support (2b), so as to reduce the likelihood of a failure due to a direct lightning strike of the phase conductors (3).

15. Renovation method according to claim 13 or 14, wherein each six-phase doublecircuit support (2b) supports a single guard rope (4) and each seven-phase support (2a) supports two guard ropes (4), so as to reduce a lightning equivalent wave impedance (Zfdg) of the electrical circuit comprising the guard ropes (4), this impedance being substantially halved, and thus reducing contact voltages (UT) and step voltages (Us) in the event of a lightning strike, as well as reducing the reverse discharge failure rate.

16. Renovation method according to any one of claims 13 to 15, wherein a vertical distance between each guard rope (4) and the high phases is lower for each seven-phase support (2a) than for each six-phase double-circuit support (2b), so as to reduce the riskof bird impact with each guard rope (4).

17. Renovation method according to any one of claims 13 to 16, wherein the sevenphase support (2a) has a smaller overall size in plan of the low electrical phases than the double-circuit supports (2b) and a lower swing length of the catenary-insulator system (L2 < LI) of the low electrical phases; optionally, wherein the seven-phase supports (2a) have an overall height equal to the replaced six-phase double-circuit supports (2b), the lower electrical phases being placed at a greater height above the ground in the seven-phase supports (2a) than in the double-circuit supports (2b) so that they interact less with the surrounding vegetation in the event of oscillation.

18. Renovation method according to claim 17, wherein, due to the smaller overall size in plan of the low electrical phases and the shorter swing length, the constrained area (FADT) of the power line before the replacement of the double-circuit supports (2b) is greater than the constrained area (FA?F) of the power line after the replacement with the seven-phase supports (2a), guaranteeing compliance with safety distances and, at the same time, reducing the interaction on mechanised agricultural work and forestry activities.

19. Renovation method according to any one of claims 13 to 18, wherein for the sevenphase supports (21), the intermediate electrical phases and the electrical phases of the third set (33a, 33b, 33c) are vertically offset with respect to the upper and lower electrical phases, and the upper electrical phases are vertically offset with respect to the guard ropes (4), thereby maintaining ice-snow resilience characteristics in relation to sleeve formation and detachment.

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