THE MAINTENANCE AND VERIFICATION OF ELECTRICAL EQUIPMENT OF A BAY

DESCRIPTION

5 Technical Field

The present invention relates to an apparatus for grounding a bay of an electrical substation that finds useful application in the maintenance and verification operations of the electrical equipment of the bay.

The present invention also relates to a method for the maintenance and 0 verification of the electrical equipment of the bay by means of the aforesaid apparatus. State of the art

The electrical substations are components of the electric power transmission network located near a production plant, at the points of delivery to the end user, and in the interconnection nodes between lines.

In detail, the electrical substations comprise a series of electrical equipment - such as, for example, switches, transformers, dischargers and the like - connected by conductors configured to convey electrical energy.

The electrical equipment requires periodic verification and maintenance operations adapted to ensure the correct operation thereof. For example, the 0 transformers must be periodically checked as they are subject to measurement errors because of wear and ageing.

To carry out the verification and maintenance operations, the bay is disconnected from the grid and, for safety reasons, grounded by means of special equipment.

The known grounding equipment comprises a clamp that can be anchored to the 5 conductor of a bay, a terminal that can be hooked to an grounding mesh, and a conductor cable that makes an electrical connection between the clamp and the terminal.

To ground a bay, the authorized personnel lift the clamp by means of a rod so as to anchor it to the conductor and connects the terminal to the grounding handle.

It should be noted that the anchoring operation, in addition to requiring the use of specialized personnel, is particularly burdensome and risky for the operator who carries it out.

In fact, the operator is required to lift and manoeuvre a rod that, due to its length of several metres, can weigh more than 6 kg. The weight of the rod itself is then added to that of the conductor cable, which is around 9 kg.

The anchoring operation is also complicated by the little manoeuvring space available inside the electrical substations, as well as by the non-optimal view that can be further aggravated by transient vision disturbances due to exposure to sunlight.

It is therefore evident that the aforementioned anchoring operations could easily unbalance the operator who could thus fall to the ground or, in the worst case, on a live bay.

In any case, the anchoring operations weigh on the back of the operators, exposing them to injuries such as stretching, contractions or herniated discs.

It is therefore evident the need to find alternative solutions for the grounding of bays of electrical substation that do not burden the operation.

Fixed apparatuses are known in the state of the art (i.e. perpetually mounted on the bay) which are configured to automate or assist the grounding operations of the bay. Examples of such fixed apparatuses are described in documents US3504142A and CN112151297A, in which specific kinematic means are configured to move in rotation a rod to connect/disconnect the bay to/from the ground.

Disadvantageously, the fixed grounding apparatuses, when not used to ground the bay, unnecessarily encumber the already overcrowded space of the electrical substations.

SUMMARY OF THE INVENTION

In this context, the task of the technician underlying the present invention is to propose an apparatus for grounding bays of electrical substations and a method for the maintenance and verification of the electrical equipment of the bays that overcome the drawbacks of the aforementioned prior art.

In particular, it is an object of the present invention to provide an apparatus for grounding bays and a method for the maintenance and verification of the electrical equipment of the bays, which do not burden the operating personnel and which do not create obstacles in the electrical substations when they are not in use.

The stated technical task and specified objects are substantially achieved by an apparatus for grounding bays of electrical substations and by a method for the maintenance and verification of the electrical equipment of the bays comprising the technical features disclosed in one or more of the appended claims.

In detail, the apparatus subject-matter of the present invention comprises a first conductor element electrically connectable to the bay and a second conductor element electrically connectable to ground.

The apparatus subject-matter of the present invention also comprises a third conductor element having a rod that extends between a first end, engageable with the first element, and a second end, engageable with the second element.

The rod is switchable between a first configuration, in which the first and second end are respectively engaged with the first and second element, and a second configuration, in which the first end is disengaged from the first element and the second end is engaged with the second element.

In the first configuration, the third element electrically connects the first and second element so as to bring the bay to the electrical potential of the soil (grounding of the bay). Otherwise, in the second configuration, the third element electrically isolates the first and second element, thus disconnecting the bay from the ground.

The apparatus further comprises kinematic means configured to move the third element, relatively to the first and second element, to switch it between the first and second configuration.

Therefore, in use, when the first and the second element are respectively electrically connected to the bay and to the ground, the user in order to ground the bay will simply have to act on the kinematic means to move the third element and bring it from the second to the first configuration. On the contrary, in order to isolate the bay from the ground, the operator will have to act on the kinematic members so as to move the third element and bring it into the second configuration.

It is therefore evident that, unlike from what is indicated in the state of the art, the operator will not have to carry out any anchoring operation to the conductor using heavy rod-like bodies, but he must simply act on the kinematic means that - by moving the rod between the first and second configuration - will connect/isolate the bay from the ground.

The apparatus also comprises hooking/unhooking members switchable between a hooking configuration, in which they hook the second end of the rod to the second element so as to retain it engaged with the latter when the rod is in the first and second configuration, and an unhooking configuration, in which they unhook the second end of the rod from the second element so as to allow the disengagement of the second end of the rod from the second element.

It should be noted that, when they are in the unhooking configuration, the hooking/unhooking members allow the rod to be switched from the second configuration into a third configuration in which both the first and second end are respectively disengaged from the first and second element.

In the third configuration, the rod is then disassembled from the first and second element, so that it can be moved outside the bay and, for example, stored in a special storage room.

To allow easy movement of the rod from and to the bay without compromising its conductive properties, the rod has a composite structure that gives it a high stiffness- to-weight ratio and excellent electrical conductivity. In detail, the rod has a conductive core adapted to electrically connect the first and second element and a stiffening coating.

It is therefore evident that the structural characteristics of the rod, by cooperating synergistically with the hooking and unhooking members, make it possible to make available an apparatus for grounding a bay capable of not burdening the operating personnel (light and rigid rod for easy movement) and, at the same time, of not creating obstacles in the electrical substations when not used to ground the bay (the rod removable from the bay - third configuration).

LIST OF FIGURES

Further features and advantages of the present invention will become clearer from the indicative, and therefore non-limiting, description of a preferred but not exclusive embodiment of an apparatus for grounding a bay for an electrical substation, as illustrated in the attached drawings in which:

- Figure 1 shows a front view of an apparatus for grounding a bay of an electrical substation according to the present invention, in detail the apparatus is represented in a first configuration in which it grounds the bay;

- Figure 2a shows a perspective view of the apparatus of Figure 1 with some components removed to better show the others;

- Figures 2b and 2c show enlargements of Figure 2a;

- Figure 3 shows a perspective view of the apparatus of Figure 1 in a second configuration in which it isolates the bay from the ground;

- Figure 4 shows a perspective view of the apparatus of Figure 1 in an intermediate configuration between the first and the second,

- Figure 5 shows a perspective view of the apparatus of Figure 1 in the first configuration;

- Figure 6 shows a possible internal structure of a component of the apparatus of Figure 1; - Figure 7a shows a perspective view of an electrical substation according to the present invention;

- Figure 7b shows an enlargement of a detail of Figure 7a,

- Figure 8a shows an embodiment of a component of the apparatus of Figure 1,

- Figure 8b shows a first detail of Figure 8a,

- Figure 8c shows a second detail of Figure 8a

- Figure 8d shows a third detail of Figure 8a.

DETAILED DESCRIPTION

With reference to the attached figures, the present invention relates to an apparatus 1 for grounding a bay 10 of an electrical substation 100.

Electrical substations are understood to be all those structures of the electric power transmission network located near a production plant, at the points of delivery to the end user and at the interconnection nodes between lines. In detail, the substations are articulated into a modular structure with several sections, in turn consisting of a system of bars and a set of branches called bays or posts. The bars are formed by a triad of conductors to which the bays are connected through the bar selectors. For example, figure 7a shows a section of a transformer bay 10.

With reference to figure 1, the apparatus 1 subject-matter of the present invention comprises a first conductor element 2 electrically connectable to the bay 10. The first element 2, being made of conductive material, leads to the electrical potential of the bay 10 when it is connected to the latter.

As shown in figure 2a and detailed in figure 2c, the first element 2 is configured to be anchored to an upper portion 10b of the bay 10, in particular to a conductor 12 for conveying electrical energy.

According to one aspect, the first element 2 comprises an anchoring portion 20 adapted to be anchored to the conductor, for example, by means of a through hole 20a. Furthermore, according to a further aspect, the first element 2 comprises a contact portion 21 configured to come into contact with a third element 4 (described below) to make a first electrical contact CE1. In the embodiment of figure 2c, the contact portion 21 comprises an engagement portion 21a - such as, for example, a seat - adapted to receive a respective portion of the third element 4 to make the first electrical contact CE1.

The apparatus 1 further comprises a second conductor element 3 electrically connectable to ground. When connected to ground, the second element 3 is brought to the electrical potential of the ground's surface, that is, to the zero potential.

Preferably, as shown in figure 2a and detailed in figure 2b, the second element 3 is anchorable to a base portion 10a of the bay 10 resting on a walking surface S (ground’s surface). When connected to the base portion 10a of the bay 10, the second element 3 is electrically grounded, i.e. it is at zero potential.

In particular, in the embodiment of figures 2a and 2b, the base portion 10a corresponds to the rest base I la of an electrical equipment 11 of the bay 10.

Electrical equipment must be understood as all those equipment typically present in a bay 10 of an electrical substation 100 - such as, for example, switches, transformers, dischargers and the like - configured to act on the electrical current flowing in a conductor.

With reference to figure 1, it should be noted that, when mounted on the bay, the first and second element 2, 3 are spaced along a vertical direction V-V extending perpendicularly to the walking surface S. Therefore, when the first and second element 2, 3 are respectively electrically connected to the bay 10 and to ground they are at a different distance from the walking surface S along the vertical distance V-V.

The apparatus 1 also comprises a third element 4 electrically connectable to the first and second element 2, 3.

The third element 4 is then configured to make the aforesaid first electrical contact CE1 with the first element 2, and a second electrical contact CE2 with the second element 3.

The third element 4 comprises a rod-like section 40, in particular a rod 43, extending along a rod direction A- A between a first end portion 41, configured to be reversibly coupled with the first element 2 to make the first electrical contact CE1, and a second end portion 42 configured to be reversibly coupled with the second element 3 to make the second electrical contact CE2. In other words, the first and second end 41, 42 are respectively engageable with the first and second element 2, 3.

With reference to figures 1 and 3, the rod 43 is switchable between a first configuration in which it is in electrical contact with both the first element 2 and the second element 3, and a second configuration in which it is disconnected from the first element 2 so as to electrically isolate the first and second element 2, 3. In detail, in the first configuration, the first and second end 41, 42 of the rod 43 are respectively engaged with the first and second element 2, 3, otherwise, in the second configuration, the first end 41 is disengaged from the first element 2 while the second end 42 remains engaged with the second element 3.

In the first configuration, the third element 4 makes an electrical bridge between the first element 2 and the second element 3 grounding the bay 10, that is, bringing it to the zero potential of the ground's surface. Therefore, when the rod 43 is in the first configuration it puts the bay 10 (already disconnected from the grid) under safe conditions so that the operators can carry out maintenance and verification operations without running any risk of electric shock or electrocution.

In the second configuration, in which the rod 43 is disengaged from the first element 2, the third element 4 electrically isolates the first and second element 2, 3. Therefore, in the second configuration, the bay 10 is free to assume electrical potentials other than those of the ground (bay electrically isolated from the ground, i.e. not grounded). The third element 4 may comprise a plurality of assemblable parts - such as, for example, a plurality of rod segments 44 described below - or be made in a single piece.

In the first configuration the rod 43 extends mainly along the vertical direction V-V (figures 1 and 5), otherwise in the second configuration the rod-like section extends mainly along a direction transverse, in particular orthogonal, to the vertical direction V-V (figure 3).

Preferably, in the first configuration the rod 43 extends along a direction parallel to the vertical direction V-V electrically connecting the first and second element 2, 3, while in the second configuration it extends transversely to the vertical direction V-V electrically isolating the first and second element 2, 3.

In embodiments alternative to those shown in the attached figures, the rod-like section 40 comprises a plurality of telescopically extractable portions for modifying the distance between the first and second end portions 41, 42 so as to switch the third element 4 between the first and second configuration.

The apparatus 1 further comprises kinematic members 5 configured to move the third element 4 with respect to the first and second element 2, 3 so as to switch the rod 43 between the first and second configuration.

Preferably, as shown in figure 6, the kinematic members 5 are integrated into the second element 3 so as to be easily accessible as they are arranged near the walking surface S.

In the other embodiment shown in figures 3-5, the kinematic members 5 are configured to rotate the third element 4, in particular the rod 43, around a rotation axis R-R with respect to the second element 3. The third element 4 by rotating around the rotation axis R-R switches between the first and the second configuration passing through a plurality of intermediate configurations, one of which is shown in figure 4.

In particular, the kinematic members 5 are configured to change the orientation of the rod 43 so as to dispose it mainly along the vertical direction V-V when it is in the first configuration, and mainly along a direction orthogonal to the vertical direction V- V when it is in the second configuration.

Preferably, the kinematic members 5 comprise a connection element 50, rotatingly mounted around the rotation axis R-R, to which the third element 4, in particular the second end 42 of the rod 43, is reversibly engageable and lockable by means of hooking/unhooking members 7 (described below). When the connection element 50 and the third element 4 are hooked - that is, as will better emerge from the following, when the hooking/unhooking members 7 in hooking configuration -, the connection element 50 is configured to rotate the third element 4 around the rotation axis R-R to switch it between the first and the second configuration.

In the embodiment shown in figures 2b and 6, the connection element 50 is rotatingly mounted on the second element 3 around the rotation axis R-R, so as to be able to switch between the positions marked as A and B in figure 6 that functionally correspond to the first and second configuration of the third element 4.

The connection element 50, in addition to performing a structural function, is therefore configured to act as an electrical bridge between the second 3 and the third element 4. To this end, the connection element 50 is made of conductive material.

According to a possible embodiment shown, the connection element 50 realizes a “plug” insertable in the second end portion 42 of the third element 4. More details on the hooking/unhooking of the second end 42 of the third element 4 with the connection element 50 will be provided in a subsequent part of the description.

Preferably, the kinematic members 5 further comprise a hinge pin 51 extending along the rotation axis R-R and to which the third element 4 can be removably constrained in rotation around the rotation axis R-R, in particular by means of the connection element 50. The third element 4 when constrained to the hinge pin 51 rotates around the rotation axis R-R to switch between the first and second configuration.

In embodiments alternative to those shown in the attached figures, the hinge pin 51 and the connection element 50 could be made as one piece.

Preferably, the apparatus subject-matter of the present invention comprises actuation members 6 configured to actuate the kinematic members 5 and to switch the third element 4 between the first and the second configuration.

These actuation members 6 can be either of the manual (e.g. crank) or electric type (e.g. electric screwdrivers or electric motors).

In the embodiment of figure 6, the kinematic members 5 comprise transmission members 52 configured to transfer the action of the actuation means 6 to the third element 4 to switch it between the first and second configuration.

In particular, the transmission members 52 are configured to convert a rotary input provided through the actuation means 6 into the rotation of the third element 4 around the rotation axis R-R in accordance with has been exposed above.

According to one aspect shown in figure 6, the transmission members 52 comprise a first bevel gear 52a operated in rotation by the actuation means 6 around a first axis Cl -Cl and a second bevel gear 52b meshed with the first bevel gear 52a and configured to rotate around a second axis C2-C2 on command of the first bevel gear 52a.

The transmission members 52 further comprise a worm gear 52c configured to transform the rotation of the second bevel gear 52b around the second axis C2-C2 into the rotation of the connection element 50 around the rotation axis R-R to switch the third element 4 between the first and the second configuration in accordance with the above.

With reference to figure 9a, the apparatus also comprises hooking/unhooking members 7 configured to removably hook the second end 42 of the rod 43 to the second element 3.

In detail, the hooking/unhooking members 7 are switchable between a hooking configuration, in which they hook the second end 42 of the rod 43 to the second element 3 so as to retain it engaged with the latter when the rod is in the first and second configuration, and an unhooking configuration, in which they unhook the second end 42 of the rod 43 from the second element so as to allow it to be disengaged from the second element 3.

It should be noted that the second end 42 of the rod 43, by disengaging and engaging with the second element 3 switches between the second configuration and a third configuration in which both the first and second end 41, 42 of the rod 43 are respectively disengaged from the first and second element 2, 3.

It should be specified that, when the rod 43 is in the third configuration, the third element 4 is electrically disconnected and kinematically decoupled from the first and second element 2, 3. Therefore, when the rod 43 is in the third configuration, it is possible to move the third element 4 - for example, to store it in a special storage room when the apparatus 1 is not used to ground the bay - leaving the first and second element 2, 3 anchored to the bay 10, i.e. already in position for the subsequent grounding of the bay.

Advantageously, this makes it possible to speed up and simplify the subsequent grounding of the bay.

Furthermore, advantageously, the removal of the third element 4 when maintenance and verification operations of the electrical equipment 11 are not in progress, allows to significantly reduce the overall dimensions of the apparatus 1 within the electrical substation 100.

Preferably, the hooking/unhooking members 7 comprise a first hooking/unhooking element 71 mounted on the second end 42 of the rod 43, and a second hooking/unhooking element 72 mounted on the second element 3 and reversibly hookable/unhookable to/from the first hooking/unhooking element 71. When the hooking/unhooking members 7 are in the hooking configuration, the first and second hooking/unhooking element 71, 72 are mutually fixed to each other. Otherwise, when the hooking/unhooking members 7 are in the unhooking configuration, the first and second hooking/unhooking element 71, 72 are decoupled so as to be mutually movable.

In the embodiment described above in which the second element 3 comprises the kinematic members 5, the second hooking/unhooking element 72 is mounted on the connection element 50 of the kinematic members 5.

According to one aspect shown in figure 9a, the first and second hooking/unhooking element 71, 72 comprise respective conical centring surfaces 71a, 72a that can be mutually abutted and configured to guide the switching of the hooking/unhooking members 7 between the hooking and unhooking configurations. Thus, advantageously, the centring surfaces 71a, 72a facilitate and speed up the engagement operation of the second end 42 of the rod 43 with the second element 3, in particular with the connection element 50.

Still with reference to the embodiment of figure 9a, the first and second hooking/unhooking element 71, 72 respectively comprise a threaded surface 71b and a threaded ring nut 72b. The threaded ring nut 72b is configured to reversibly couple with the threaded surface 71b of the first hooking/unhooking element 71 so as to mutually fix the first and second hooking/unhooking element 71, 72 in a removable manner.

In accordance with what is shown in figures 8b and 9b, the rod comprises an electrically conductive core 43a and a stiffening coating 43b.

The core 43a is configured to electrically connect the first and second element 2, 3 when the rod 43 is in the first configuration, while the stiffening coating 43b is configured to increase the flexural stiffness of the rod 43.

With reference to the embodiments shown in figures 8b and 9b, the stiffening coating 43b is arranged externally to the core 43a.

According to one embodiment, the stiffening coating 43b is made of carbon fibre.

Advantageously, the low density and the high Young's modulus of the carbon fibre allow the flexural stiffness of the rod 43 to be significantly increased without significantly impacting its weight.

Preferably, the stiffening coating 43b is made of pitch-type carbon fibre. It should be noted that the use of this type of carbon fibre is particularly suitable for the construction of the rod 43, since among the types of carbon fibres it is the one with the highest Young's modulus and the lowest electrical resistance value. In fact, the pitchtype carbon fibre is the product closest to graphite.

Preferably, the stiffening coating 43 has a thickness comprised between 1 mm and 1.5 mm, in particular of 1.3 mm. Advantageously, these thicknesses allow to obtain a sufficient stiffening of the rod 43 without excessively increasing its weight.

Preferably, the stiffening coating 43b of carbon fibre is laid on the core 43a with the fibres oriented parallel to the rod direction A-A. Advantageously, such an arrangement of the fibres allows the flexural stiffness of the rod 43 to be maximised.

According to one aspect, the core 43a is made of metallic material, in particular of aluminium or stainless steel or copper.

With reference to the embodiment shown in figures 8b and 9b, the core 43a has a tubular shape that extends along the rod direction A-A between the first and second end 41, 42.

Preferably, the core 43a has a circular cross-section characterized by a diameter comprised between 40mm and 60mm and a thickness comprised between 1mm and 2mm. In particular, in a preferred embodiment, the rod has a circular cross-section characterized by a diameter equal to 50mm and a thickness of 1 ,5mm. Advantageously, such geometries of the core 43a allow to obtain good conductivity values of the rod 43.

In the embodiment of figure 8a, the third element 4 comprises a plurality of rod segments 44 extending between opposite mutually joinable end portions 44t.

Each rod segment 44 comprises a respective section 430a of core 43a with a relative stiffening coating portion 430b. A rod segment 44 is shown individually in figure 8c. The rod segments 44 are switchable between an assembled configuration, in which they are mutually joined at the respective end portions 44t, realizing in this way the aforesaid rod 43, and a disassembled configuration, in which they are mutually disconnected so as to be individually transportable and storable when the rod is in the third configuration.

In the assembled configuration the rod segments 44 are arranged in series along the rod direction A- A with the joined end portions 44t. It should be noted that in the assembled configuration, the free end portions 44t of the end rod segments 44 define the first and second end 41, 42 of the rod 43.

It should be specified that, when the plurality of rod segments 44 are in the assembled configuration, the respective sections 430a of the core 43a are electrically connected so that the rod 43 is able to conduct electric current between the first and second end 41, 43.

Preferably, the third element 4 also comprises a plurality of joining inserts 45 arranged at the end portions 44t of each rod segment 44. Such joining inserts 45 are configured to removably join the rod segments 44 to switch them between the assembled and disassembled configuration.

These joining inserts 45 are made of electrically conductive material, so as to place the sections 430a of the core 43 a in electrical continuity when the rod segments 44 are in the assembled configuration.

With reference to the embodiment of figure 8d, the joining inserts 45 comprise male joining inserts 45a and female joining inserts 45b, complementarily removably couplable. Each rod segment 44 comprises a male joining insert 45a and a female joining insert 45b which are arranged at opposite end portions 44t.

In the embodiment of figure 8b, the sections 430a of the core 43 a have a tubular conformation that extends between the end portions 44t of the respective rod segments 44. The joining inserts 45 are keyed on the sections 430a of the core 43a at the end portions 44t, preferably through a cryogenic keying process with liquid nitrogen. Advantageously, by doing so it is possible to avoid the use of adhesives that would affect the electrical conductivity of the rod by increasing its electrical resistance at the interface between the sections 430a of the core 43 a.

It is also an object of the present invention a method for the maintenance and verification of electrical equipment 11 of a bay 10 of an electrical substation 100, by means of an apparatus 1 for grounding the bay 10 which comprises: a first conductor element 2; a second conductor element 3; a third element 4 having a rod 43 extending between a first end 41, engageable with the first element 2, and a second end 42, engageable with the second element 3; kinematic members 5 configured to move the third element 4 with respect to the first and second element 2, 3; and hooking/unhooking members 7 configured to hook/unhook the second end 42 of the rod 43 with/from the second element 3.

Preferably, the apparatus used in such method for the maintenance and verification of the electrical equipment 11 of the bay 10 is the apparatus 1 described above.

The method object of the present invention comprises an initial set-up step and periodic (at least one) maintenance steps.

The set-up step is performed once upstream of the maintenance steps. In other words, the set-up step is preparatory for each of the subsequent maintenance steps.

In detail, this set-up step provides for the sub-steps of anchoring the first element 2 to a conductor 12 for conveying electrical energy of the bay 10, and the second conductor element 3 to an grounded base portion 10a of the bay 10. Once anchored, the first and second element 2, 3 are in electrical continuity respectively with the conductor 12 and the base portion 10a of the bay 10.

Each maintenance step involves the execution of a plurality of sub-steps, described below.

The maintenance step first comprises a first sub-step in which the second end 42 of the rod 43 is engaged and hooked to the second element 3.

Preferably, in the first sub-step the rod 43 is switched from the third and to the second configuration and the hooking/unhooking members 7 are brought into the hooking configuration.

The maintenance step comprises a second sub-step in which the kinematic members 5 are operated to move the third element 4 so as to engage the first end 41 of the rod 43 with the first element 1 and to ground the conductor 12 of the bay 10. Therefore, downstream of the second sub-step, the bay is secured so that operators can intervene on the electrical equipment without running the risk of electric shock or electrocution.

Preferably, in the second sub-step the rod 43 is switched from the second to the first configuration. In the second sub-step the hooking/unhooking members 7 are kept in the hooking configuration to prevent the disengagement of the rod 7 from the second element 3 during switching from the second to the first configuration.

Subsequently, the maintenance step comprises a third sub-step in which the envisaged maintenance and verification operations of the electrical equipment 11 are carried out.

Upon completion of the maintenance and verification operations, the maintenance step provides for a fourth sub-step in which the third element 4 is moved so as to disengage the first end 41 of the rod 43 from the first element 1 and, therefore, electrically disconnect the conductor 12 of the bay 10 from ground.

Preferably, in the fourth sub-step the rod 43 is switched from the first to the second configuration.

The maintenance step also provides for a fifth sub-step that provides for unhooking and disengaging the second end 42 of the rod 43 from the second element 3, leaving the first and second element 2, 3 respectively anchored to the conductor 12 and to the base portion 10a of the bay 10, i.e. as arranged in the set-up step.

Preferably, in the fifth sub-step the hooking/unhooking members 7 are brought from the hooking configuration to the unhooking configuration and the rod 43 switched from the second configuration to the third configuration.

Therefore, the method subject-matter of the present invention allows to store the rod 43 - for example, in special storage environments - when maintenance and verification activities of the electrical equipment are not being carried out. Advantageously, this allows to reduce the overall dimensions of the apparatus 1 inside the electrical substation 100 when not used to ground the bay 10.

It should also be noted that the subsequent maintenance and verification operation of the electrical equipment of the bay is facilitated and speeded up by the fact that the first and second element 2, 3 are already anchored to the bay 10. Therefore, in this way, the first and second element 2, 3 are already in position and ready to engage with the rod 43 at the subsequent maintenance and verification operation, so that it is not necessary to perform the set-up step again.

If the rod has the structure of figure 8a, the maintenance step provides for an initial sub-step (upstream of the first sub-step) in which the plurality of rod segments 44 are assembled to define the rod 43 and a final sub-step (downstream of the fifth substep) in which the plurality of rod segments 44 are disassembled so as to be individually transportable and storable.