Load-bearing structure, power plant provided with such a load-bearing structure and method for adjusting such a load-bearing structure

Abstract

The invention relates to a load-bearing structure (3) comprising: - a support table (5) supported by at least four posts (17), each post (17) carrying, at its upper end, a connection member (19) connecting the support table (5) to the post (17); - at least four altimetric variation sensors configured to measure the relative altimetric variation of the support table (5); - a distance sensor configured to measure the distance between the upper end of a reference post (27) and the support table (5); and - an adjustment system configured to stabilise the deformation of the support table (5) according to measurements from the altimetric variation sensors (21) and the distance sensor (25). The invention also relates to a power plant (1) comprising such a load-bearing structure (3), and to a method for adjusting such a load-bearing structure (3).

Description

[0001] Supporting structure, power plant provided with such a supporting structure and method for adjusting such a supporting structure

[0002] TECHNICAL FIELD

[0003] The present application relates to a supporting structure, as well as a method for adjusting such a supporting structure. The invention also applies to a power plant comprising such a supporting structure, in particular supporting a rotating machine, such as a turbo-alternator group.

[0004] STATE OF THE ART

[0005] Traditionally, power plants, particularly nuclear or thermal power plants, include a turbo-alternator unit, which is a rotating machine used to produce electricity from pressurized steam. Such a turbo-alternator unit consists of a steam turbine and an alternator.

[0006] Such a turbo-alternator group is supported by a support table, also called a group table. Such a support table rests on posts conventionally made of reinforced concrete, and forms with them a load-bearing structure. These posts are subject to non-uniform thermal variations, for example due to the alternation of day and night, in particular the diurnal cycle of sunrise and sunset, and / or the start-up of auxiliary equipment nearby in the same enclosed space, also called the engine room. The different expansions depending on the posts cause deformation of the support table. Such deformation makes the topography and alignment operations of the turbo-alternator group particularly difficult, if not impossible. Indeed, the expansions of the posts due to thermal variations can be faster than the adjustment operations (topographic measurements, alignment).

[0007] Thus, for example, when adjusting the steam turbine, the relative positions between the shaft line and the bearings must be precisely adjusted to ensure proper operation of the steam turbine and the alternator. Any imperfections and alignment errors in the steam turbine can have significant consequences on the dynamic stability of the bearings and can thus cause operating difficulties or even significant damage to the bearings supporting the shaft line of the turbo-alternator group.

[0008] In order to allow the adjustment of the turbo-alternator group, the altimetric auscultation of the steam turbine by NTHP (very high precision leveling) is carried out and the adjustment operations of the bearings are then carried out. However, they require stability of the support table over time. Due to the effects of diurnal cycles and / or start-ups of auxiliary equipment, for example pumps, thermal variations in the engine room cause significant expansions of the columns over relatively short time variables compared to the adjustment operations, due to the fact that these are slender structures with low thermal inertia.

[0009] Due to non-uniform temperature changes in the engine room, some posts expand or contract more than others, for example by a few millimeters. These differential altimetric variations are reflected in the distribution of forces transmitted - directly or more generally indirectly, for example, by spring boxes - by the posts to the support table. Thus, the support table deforms over time, mainly altimetrically - in other words vertically -, the deformations along the plane of the support table - in other words horizontally - being comparatively negligible.Such deformations result from altimetric variations at the posts, for example of several hundred micrometers, making topographical measurements and adjustment of the turbo-alternator group quite hazardous and imprecise, especially since the effects of thermal variations are faster than the measurement / adjustment / alignment operations.

[0010] Thus, difficulties exist during the turbo-alternator group alignment operations, although precautions are taken to limit thermal variations in the engine room. To this end, the engine room doors are closed several hours before the start of the topography and alignment operations. As a result, thermal loads are experienced and the means implemented to counter them are passive, such as for example: closing the doors several hours before the intervention, no start-up of auxiliary equipment.

[0011] Topography and alignment operations can be carried out at night and auxiliary equipment start-ups causing local hot spots are avoided. However, the problem of deformation of the support table persists. Thus, the quality of the topography and the adjustment of the turbo-alternator group depends on uncontrollable parameters such as, for example, sunlight, the effects of which are amplified when the engine room has a south-facing glass roof, and is therefore particularly uncertain.

[0012] The possible movements of the support table are vertical displacements along the Z axis, rotation around the X axis also called rolling, rotation around the Y axis also called pitching, and deformation, for example hyperbolic paraboloid or "saddle" type or torsion type. Solutions have been considered such as thermal insulation of the columns, air conditioning in the machine room or locally at the level of the columns. However, these solutions appear difficult to implement.

[0013] STATEMENT OF THE INVENTION

[0014] An aim of the present application is to remedy the aforementioned drawbacks, by proposing a supporting structure limiting the influence of the expansion of the posts on the deformation of the support table, in order to obtain dimensional stability of the support table over time. Dimensional stability should be understood to mean geometric stability.

[0015] To this end, the invention proposes, according to a first aspect, a supporting structure, comprising:

[0016] - a support table supported by at least four posts, each post carrying, at its upper end, a connecting member connecting the support table to the post,

[0017] - at least four altimetric variation sensors, each altimetric variation sensor being configured to measure the relative altimetric variation E of the support table,

[0018] - a distance sensor configured to measure the distance between the upper end of a reference post and the support table, the reference post being selected from among the posts, and

[0019] - an adjustment system configured to stabilize the deformation of the support table, the adjustment system comprising a set of actuators such that each post carries an actuator arranged between the post and the support table, the actuator being configured to modify the distance between the post and the support table according to measurements from the altimetric variation sensors and the distance sensor.

[0020] Thus, the proposed solution does not seek to regulate the temperature but to compensate the forces generated by the thermal expansions and contractions of the columns on the support table thanks to the adjustment system. As a result, the altimetric variations due to the expansions of the columns induced by non-uniform thermal loads in the machine room are compensated in order to avoid deformations of the support table preventing the performance of topographic measurements and alignment operations. The supporting structure compensates, via actuators, the thermal expansions of the columns and thus stabilizes, limits or prevents deformation of the support table, which guarantees its dimensional stability in the vertical direction. Consequently, adjustment operations, for example topographic and alignment measurements, can be carried out without being disturbed over time by thermal variations.The use of an active system thus makes it possible to limit the constraints during topography and adjustment operations of the rotating machine, which is stopped during these operations, by guaranteeing stability of the support table in the vertical direction (roll, pitch and vertical deformations) over time. Furthermore, the device can also position and deform the table, so as to find precise and specified adjustment conditions, for example from previous alignment / adjustment campaigns.

[0021] The altimetric variations of the support table at the posts are known from the measurements made by both the altimetric variation sensors and the distance sensor. In other words, the local altimetry of the support table at the post in relation to the reference post is obtained by adding the distance value, the altimetric variation value between the altimetric variation sensor at the post in relation to the reference post and the altimetric variation sensor at the post in question. Each altimetric variation sensor makes it possible to know the relative altimetric variation of the support table at the altimetric variation sensor in relation to the other altimetric variation sensors. The distance sensor makes it possible to deduce the local altimetry of the support table in relation to the upper end of a post, identified as a reference post.Thus, it is possible to maintain dimensional stability in the vertical direction of the support table while limiting the stroke of the actuators, due to the fact that the expansion of the reference post is not compensated, the adjustment system thus only compensating for the deformations of the support table, without maintaining its absolute vertical position - also called global altimetry -, that is to say its vertical position relative to the foot of the posts, that is to say relative to the floor or the raft.

[0022] This therefore makes it easier to adjust an element supported by the support table, such as a rotating machine, in particular a turbo-alternator group.

[0023] In case of deformation of the support table, the altimetric variation observed by an altimetric variation sensor gives an altimetric variation at the observation point. For example, positioned equidistant from four posts, it will give an average altimetric variation of the area between the four posts without being able to observe possible deformations. Thus, to detect the deformation of the support table supported by at least four columns, a minimum of four altimetric variation sensors is required.

[0024] The supporting structure according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0025] - The supporting structure is configured to support a rotating machine. This makes it easier to adjust the rotating machine. - Each height variation sensor is positioned closer to a post than the other height variation sensors.

[0026] - Each altimetric variation sensor is configured to measure the altimetric variation of the support table at the level of the post to which it is closest.

[0027] - Each altimetric variation sensor is configured to measure the altimetric variation of the support table at a different point than the other altimetric variation sensors. Thus, the deformation of the support table is optimally measured.

[0028] - The altimetric variation sensors are arranged at different points on the support table and are configured to measure the altimetric variation of the support table at these different points. Thus, the deformation of the support table is optimally measured.

[0029] - The number of height variation sensors is equal to the number of posts. Thus, the deformation of the support table is optimally measured.

[0030] - Each altimetric variation sensor is positioned in line with a post, preferably arranged on the support table, under the support table or in the thickness of the support table. Thus, the adjustment system allows for particularly precise adjustment at each post, since the measurement made by each altimetric variation sensor is located locally at the same place as the actuator carrying out the adjustment for the post.

[0031] - The actuator is configured to modify the distance between the post and the support table based on measurements from the height variation sensors, the distance sensor and a preference setpoint defined by a user.

[0032] - The distance between the post and the support table is modified by the actuator based on measurements from the altimetric variation sensors, the distance sensor and a preference setpoint defined by a user.

[0033] - Each altimetric variation sensor is a laser sensor or an H LS sensor (for Hydrostatic Leveling System). Such altimetric variation sensors allow very precise measurement of altimetric variation, with a measurement accuracy of the order of a few micrometers.

[0034] - Altimetric variation sensors are hydrostatic leveling pots. Such altimetric variation sensors are particularly precise, with a measurement accuracy of the order of a micrometer (measurement noise less than a micrometer).

[0035] - The distance sensor is positioned to the right of the reference post.

[0036] - The supporting structure comprises at least ten posts, preferably sixteen posts.

[0037] - The support table is made of reinforced concrete or steel.

[0038] - The support table has a length between 30 meters and 100 meters, preferably 60 meters. - The support table has a width between 10 and 50 meters, preferably between 20 and 30 meters.

[0039] - The support table supports a rotating machine, preferably a turbo-alternator unit. Thus, the adjustment operations of the rotating machine, and preferably of the turbo-alternator unit, are particularly improved.

[0040] - Each post is made of steel or reinforced concrete. This design is particularly robust and allows the number of posts to be limited, particularly because such posts are particularly resistant to compression, which is due to the significant mass of the support table supported by the posts.

[0041] - Each column is made of steel. Indeed, external threats, such as earthquakes, may have to be taken into account when designing the supporting structure. Thus, the use of steel columns may be preferred, however they nevertheless have an increased sensitivity to thermal variations compared to reinforced concrete columns, in particular due to their lower thermal inertia, which amplifies the deformations of the support table. This greater sensitivity reduces the altimetric stability of the support table, which, in the absence of a supporting structure in accordance with the invention, could result in particularly significant difficulties during topography and adjustment operations, in particular alignment, of the rotating machine.

[0042] - Each post has a height between 10 meters and 30 meters, preferably a height between 15 meters and 20 meters. This height is particularly suitable for allowing auxiliary equipment to be placed under the support table.

[0043] - The connecting member comprises an element whose rigidity is lower than that of the support table and that of the post, preferably a spring element. Thus, the vibrations resulting from the operation of the rotating machine, in particular the steam turbine of the turbo-alternator group, are transmitted to the posts in a limited manner, a fortiori to the elements arranged near the supporting structure, such as neighboring civil engineering structures.

[0044] - The spring-forming element comprises at least one spring box inserted between the post and the support table, preferably between three and six spring boxes inserted between the post and the support table. These spring boxes make it possible to dynamically isolate the support table from the posts as well as from the rest of the civil engineering when the rotating machine, in particular the steam turbine of the turbo-alternator group, is in operation.

[0045] - Each spring box comprises two metal plates between which a plurality of springs are interposed. - The actuator assembly is composed of hydraulic actuators, preferably hydraulic cylinders, more preferably double-acting hydraulic cylinders. The use of hydraulic force is particularly advantageous, each actuator being thus adapted to the transmission of significant forces aimed at locally modifying the altimetric position of the support table, which may have a mass of the order of a thousand tonnes.

[0046] - Each actuator is arranged between the upper end of a post and the support table and preferably comes into direct contact with the support table.

[0047] - Each actuator is arranged in a spring box inserted between the post and the support table. Thus, actuation can be achieved by compression or traction, regardless of the material making up the post and the material making up the support table.

[0048] - The adjustment system comprises a control circuit, the control circuit controlling the set of actuators from measurements of the altimetric variation sensors, the distance sensor and a preference setpoint defined by a user.

[0049] - The adjustment system comprises a user interface, which is connected to the control circuit and is configured to allow a user to define the deformation of the support table. Thus, the user can choose to stabilize the deformation of the support table according to a predefined or desired model. This may for example be the deformation of the table as present in a previous adjustment campaign.

[0050] - Alternatively or in addition to the feature that the supporting structure is such that each altimetric variation sensor is configured to measure the relative altimetric variation of the support table, the supporting structure comprises, for each post, an altimetric variation sensor configured to measure the altimetric variation of the upper end of the post. Thus, the altimetric variations of the posts are known precisely from the measurements made by each altimetric variation sensor.

[0051] According to a second aspect, the invention provides a power plant comprising a supporting structure according to the first aspect.

[0052] The power plant according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0053] - The power plant is a nuclear power plant.

[0054] - The power plant is a thermal power plant. According to a third aspect, the invention provides a method for adjusting a supporting structure according to the first aspect, which comprises the following steps:

[0055] - measure the relative altimetric variation by each altimetric variation sensor,

[0056] - measure the distance by the distance sensor,

[0057] - for each post, determine a local altimetric value of the support table relative to the upper end of the reference post based on the measurement of the relative altimetric variation carried out by the altimetric variation sensor closest to the post and the measurement of the distance carried out by the distance sensor, and determine an error resulting from a comparison of the local altimetric value with a set value called the setpoint,

[0058] - for each post, from the setpoint value, control the actuator carried by the post so as to minimize the error value relating to each altimetric variation sensor. In other words, the actuator carried by the post is controlled until the support table undergoes an altimetric variation minimizing the error so that the altimetric position of the table tends towards the setpoint.

[0059] This makes adjusting the supporting structure easy.

[0060] The adjustment method according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0061] - The adjustment method further comprises the following step, alternative or complementary to the aforementioned steps, consisting of measuring the relative altimetric variation by each altimetric variation sensor, measuring the distance by the distance sensor, for each post, determining a local altimetric value of the support table relative to the upper end of the reference post as a function of the measurement of the relative altimetric variation carried out by the altimetric variation sensor closest to the post and the measurement of the distance carried out by the distance sensor, and determining an error resulting from a comparison of the local altimetric value with a set value called the setpoint:

[0062] - for each post, measure the altimetric variation of the upper end of the post using the altimetric variation sensor, estimate a local altimetric value of the support table relative to the upper end of the post based on all the altimetric variation measurements, a model of the supporting structure, and determine an error value resulting from a comparison of the local altimetric value with a set value.

[0063] - The setpoint value is predefined, preferably equal to a previously obtained altimetric value based on a previous measurement of the altimetric variation and a previous measurement of the distance. Thus, it is possible to maintain the support table in the same configuration as during the previous measurement, which allows adjustment operations to be carried out without further deformation of the support table occurring or in such a way that further deformation of the support table is imposed in order to return to a previous adjustment configuration.

[0064] - The adjustment process further comprises the following steps:

[0065] - enter a correction instruction using the user interface, the correction instruction being a function of at least one value of the support table chosen from a deformation value, a roll value, a pitch value and an altimetric displacement value preferably relative to the reference post,

[0066] - based on the correction instruction and for each post, calculate a command value for the actuator carried by the post.

[0067] - The setpoint value is greater than a predetermined minimum value, and less than a predetermined maximum value. Thus, the setpoint value cannot exceed the technical constraints of the actuator, particularly in terms of travel and force.

[0068] - The steps of the adjustment process are carried out when the rotating machine is stopped.

[0069] DESCRIPTION OF FIGURES

[0070] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which:

[0071] Figure 1 is a schematic front view of a power plant comprising a supporting structure according to one embodiment;

[0072] Figure 2 is a schematic bottom view of a support table forming part of the supporting structure shown in Figure 1;

[0073] Figure 3 is a schematic and partial view of a detail of the supporting structure according to one embodiment;

[0074] Figure 4 is a schematic partial front view of the supporting structure according to one embodiment;

[0075] Figure 5 is a schematic and partial view of a detail of the supporting structure according to an alternative embodiment;

[0076] Figure 6 schematically represents the steps of a method of adjusting the supporting structure according to one embodiment;

[0077] Figure 7 schematically represents the steps of a method of adjusting the supporting structure according to an alternative embodiment. In all the figures, similar elements bear identical references.

[0078] DETAILED DESCRIPTION

[0079] Figure 1 represents a power plant 1 comprising a supporting structure 3. The power plant 1 is advantageously a nuclear power plant or a thermal power plant.

[0080] The supporting structure 3 comprises a support table 5. Advantageously, thanks to the support table 5, the supporting structure 3 is configured to support a rotating machine 7.

[0081] The support table 5 is advantageously made of reinforced concrete or steel.

[0082] The support table 5 has a length of between 30 meters and 100 meters, preferably equal to 60 meters. The length is shown along the X axis in Figure 1.

[0083] So, the X axis is a longitudinal axis, the Y axis is a transverse axis orthogonal to the X axis, and the Z axis is a vertical axis orthogonal to both the X axis and the Y axis.

[0084] As shown in Figure 2, the support table 5 may comprise longitudinal support beams 9 and transverse support beams 11.

[0085] The support table 5 has a width of between 10 and 50 meters, preferably between 20 and 30 meters. The width is shown along the Y axis in Figure 2.

[0086] The support table 5 supports a rotating machine 7, preferably a turbo-alternator group. Such a turbo-alternator group advantageously comprises a steam turbine 13 and an alternator 15.

[0087] The support table 5 is supported by at least four posts 17. Advantageously, the supporting structure 3 comprises at least ten posts 17, preferably sixteen posts 17.

[0088] Each post 17 is made of reinforced concrete or steel.

[0089] Each post 17 has a height of between 10 meters and 30 meters, preferably a height of between 15 meters and 20 meters.

[0090] Each post 17 carries, at its upper end - more precisely taken along the Z axis, which is a vertical axis as shown in Figure 1 -, a connecting member 19 connecting the support table 5 to the post 17.

[0091] The supporting structure 3 also comprises at least four altimetric variation sensors 21.

[0092] Advantageously, as shown in Figure 2, the number of altimetric variation sensors 21 is equal to the number of posts 17. Preferably, each altimetric variation sensor 21 is configured to measure the relative altimetric variation of the support table 5.

[0093] Advantageously, each altimetric variation sensor 21 is configured to measure the relative altimetric variation of the support table 5 with respect to the other altimetric variation sensors 21.

[0094] Advantageously, each altimetric variation sensor 21 is arranged closer to a post 17 than the other altimetric variation sensors 21. Preferably, each altimetric variation sensor 21 is configured to measure the altimetric variation of the support table 5 at the post 17 to which it is closest.

[0095] Advantageously, each altimetric variation sensor 21 is configured to measure the altimetric variation of the support table 5 at a point different from those of the other altimetric variation sensors 21. Preferably, the altimetric variation sensors 21 are arranged at different points of the support table 5 and are configured to measure the altimetric variation of the support table 5 at these different points.

[0096] Advantageously, as shown schematically in Figure 2 and Figure 3, each altimetric variation sensor 21 is positioned in line with a post 17, preferably arranged on the support table 5, under the support table 5, or in the thickness of the support table 5.

[0097] Preferably, each altimetric variation sensor 21 is an HLS sensor, for Hydrostatic Leveling System. Advantageously, the altimetric variation sensors 21 are hydrostatic leveling pots. In this case, as shown in Figure 2, the altimetric variation sensors 21 are preferably connected to each other by a hydrostatic leveling network 23. Advantageously, such a hydrostatic leveling network 23 is composed of a free-surface air / water pipe, in other words a pipe containing air and water and in which the interface between the air and the water is free. The altimetric variations are in reality relative altimetric variations between the different altimetric variation sensors 21.The local altimetric variations, that is to say between the support table 5 and each upper end of the post 17 closest to the altimetric variation sensor 21 considered, and global altimetric variations, that is to say between the support table 5 and the ground or the floor supporting each post 17, are not observed by the altimetric variation sensors 21.

[0098] The supporting structure 3 also comprises a distance sensor 25. Advantageously, the distance sensor 25 is configured to measure the distance between the upper end of a reference post 27 and the support table 5. The reference post 27 is chosen from the posts 17. Advantageously, as shown schematically in FIG. 3, the distance sensor 25 is positioned in line with the reference post 27. On the contrary, a post 17 not forming the reference post 27 is identical to the schematic representation of FIG. 3, except in that it does not comprise a distance sensor positioned in line with the post 17.

[0099] As shown in Figure 3, the connecting member 19 comprises an element whose rigidity is lower than that of the support table 5 and that of the post 17, preferably a spring element. Advantageously, the spring element comprises at least one spring box 29 interposed between the post 17 and the support table 5, preferably between three and six spring boxes 29 interposed between the post 17 and the support table 5.

[0100] Advantageously, each spring box 29 comprises two metal plates 31, 33, between which a plurality of springs 29 are interposed.

[0101] As shown in Figure 4, the supporting structure 3 also comprises an adjustment system 37. The adjustment system 37 is configured to stabilize the deformation of the support table 5.

[0102] The adjustment system 37 comprises a set of actuators 39. Advantageously, the set of actuators 39 is composed of hydraulic actuators, preferably hydraulic cylinders, more preferably double-acting hydraulic cylinders. Thus, an actuator 39 may comprise a single hydraulic actuator, preferably a hydraulic cylinder, more preferably a double-acting hydraulic cylinder. Alternatively, an actuator 39 may comprise a plurality of hydraulic actuators, preferably hydraulic cylinders, more preferably double-acting hydraulic cylinders.

[0103] Advantageously, each post 17 carries an actuator 39 arranged between the post 17 and the support table 5, as is schematically shown in Figure 4, in which only three posts 17 - one of which is the reference post 27 - are shown, for the sake of simplification. The actuator 39 is configured to modify the distance between the post 17 and the support table 5. Preferably, the distance between the post 17 and the support table 5 is modified by the actuator 39 as a function of measurements from the altimetric variation sensors 21 and the distance sensor 25.

[0104] Preferably, the actuator 39 is configured to modify the distance between the post 17 and the support table 5 as a function of measurements from the altimetric variation sensors 21, the distance sensor 25 and a preference setpoint defined by a user. Thus, the distance between the post 17 and the support table 5 is modified by the actuator 39 as a function of measurements from the altimetric variation sensors 21, the distance sensor 25 and a preference setpoint defined by a user.

[0105] Advantageously, each actuator 39 is arranged between the upper end of a post 17 and the support table 5. Preferably, each actuator 39 is arranged in a spring box 29 interposed between the post 17 and the support table 5, as is for example shown schematically in FIG. 3. Alternatively, according to a variant not shown, each actuator 39 comes into direct contact with the support table 5.

[0106] Advantageously, the adjustment system 37 comprises a control circuit 41, as shown schematically in FIG. 4. The control circuit 41 controls the set of actuators 39 from measurements of the altimetric variation sensors 21 and the distance sensor 25, and from a preference setpoint defined by a user.

[0107] Advantageously, a default instruction is consistent with the state of the supporting structure 3 when the control circuit 41 is put into service.

[0108] For example, when each actuator 39 is a hydraulic cylinder, preferably a double-acting hydraulic cylinder, the control circuit 41 controls a pump 43 and a distribution member 45, which supply each actuator 39 with hydraulic fluid, and this independently, on the basis of a control value C specific to each actuator 39. Each actuator 39 can thus locally modify the altimetric position of the support table 5, which in particular makes it possible to stabilize the deformation of the support table 5 when the posts 17 expand in a differentiated manner.

[0109] Advantageously, the adjustment system 37 comprises a user interface 47, which is connected to the control circuit 41 and is configured to allow a user to control the deformation of the support table 5.

[0110] Preferably, the user interface 47 is configured to allow the user to enter:

[0111] - a deformation value; thus, a deformation of the support table 5 can be chosen and stabilized by entering for each altimetric variation sensor 21 a deformation value, representative of a specific relative altimetry to be achieved; if the aim is to keep the support table 5 flat, in other words without deformation, a zero value is entered or entered by default; a non-zero deformation value makes it possible to deform the support table and to place the support table in adjustment conditions desired by the user; in other words, the user enters a desired deformation (for example zero deformation over time), then this deformation is used to calculate a setpoint value R used to calculate a control value C for controlling the actuator 39 at each post 17;

[0112] - a roll value, namely a rotation of the support table 5 around the X axis, preferably by entering an angle between -0.05° and 0.05°; the roll value being zero by default;

[0113] - a pitch value, namely a rotation of the support table 5 around the Y axis, preferably by entering an angle between -0.05° and 0.05°; the pitch value being zero by default;

[0114] - an altimetric displacement value, namely a displacement of the support table 5 along the Z axis relative to the upper end of the reference post, preferably by entering an altimetric displacement value between -2 millimeters and 2 millimeters; the altimetric displacement value being zero by default.

[0115] Alternatively or in addition to the feature that the supporting structure 3 is such that each altimetric variation sensor 21 is configured to measure the altimetric variation of the support table 5, the supporting structure 3 comprises, for each post 17, an altimetric variation sensor 21 configured to measure the altimetric variation of the upper end of the post 17, as shown in FIG. 5. Optionally, the supporting structure 3 does not comprise a distance sensor 25.

[0116] Figure 6 represents the main steps of a method of adjusting a supporting structure 3 as defined previously.

[0117] Such an adjustment process involves the following steps:

[0118] - P100 measure the relative altimetric variation V by each altimetric variation sensor 21,

[0119] - P110 measure the distance D by the distance sensor 25,

[0120] - for each post 17, P120 determine a local altimetric value A of the support table 5 at the post 17 relative to the upper end of the reference post 27 as a function of the measurement of the relative altimetric variation V carried out by the altimetric variation sensor 21 closest to the post 17 and of the measurement of the distance D carried out by the distance sensor 25, and P130 determine an error value E resulting from a comparison of the local altimetric value A with a setpoint value R, the setpoint value R preferably being a setpoint defined by a user and capable of being corrected as a function of the constraints imposed on the control of the actuators 39,

[0121] - for each post 17, from the error value E, P140 controls the actuator 39 carried by the post 17, so as to minimize the error value E relating to each altimetric variation sensor 21.

[0122] Advantageously, step P140 is carried out by the adjustment system 37, preferably by the control circuit 41. Advantageously, the steps of the adjustment method are carried out when the rotating machine 7 is stopped.

[0123] Advantageously, the steps of the adjustment method can be carried out in real time, or repeated at a predefined frequency, in order to achieve a servocontrol of the movement of the support table 5 at the action point. Feedback loops are thus produced, for example of the PI type for “proportional integral”. Thus, at each time step, each actuator 39 at each post 17 has a specific control value C applied to it.

[0124] Advantageously, the control circuit 41 is configured to carry out steps P120, P130 and P140 of the adjustment method. Preferably, step P140 is carried out by the control circuit 41, which thus selectively controls each actuator 39 by means of the pump 43 and the distribution member 45.

[0125] Advantageously, the adjustment method is such that the setpoint value R is predefined, preferably equal to a local altimetric value A obtained previously as a function of a previous measurement of the relative altimetric variation V and a previous measurement of the distance D.

[0126] Advantageously and as shown in Figure 7, the adjustment method is such that the control value C is greater than a predetermined minimum value Cmin, and less than a predetermined maximum value Cmax.

[0127] Advantageously, Cmax is between 0.6 and 2 millimeters, preferably between 0.6 and 1.2 millimeters. For example, when each actuator 39 can only be used in one direction, a constraint forcing the actuators 39 to work only in compression is imposed. Alternatively, for example when the actuator 39 can work in tension / compression, Cmin is between -2 millimeters and 2 millimeters, preferably between -1.2 millimeters and 1.2 millimeters.

[0128] The predetermined minimum value Cmin and the predetermined maximum value Cmax may depend on a maximum force applicable by the actuator 39 and / or on a maximum control value C not to be exceeded.

[0129] Advantageously, the adjustment method is such that it further comprises the following steps:

[0130] - P150 enter a correction setpoint CC by means of the user interface 47, the correction setpoint CC being a function of at least one value of the support table 5 chosen from a deformation value, a roll value, a pitch value and an altimetric displacement value preferably relative to the reference post 25, and optionally the predetermined minimum value Cmin and the predetermined maximum value Cmax, - as a function of the correction setpoint CC and for each post 17, P160 calculate a control value C for the actuator 39 carried by the post 17.

[0131] Advantageously, the control circuit 41 is configured to carry out step P160 of the adjustment method, preferably in real time.

[0132] Optionally, the adjustment method further comprises the following step shown in Figure 7, alternative or complementary to the aforementioned steps P100, P110 and P120:

[0133] - for each post 17, P170 measure the altimetric variation VA of the upper end of the post 17 by means of the altimetric variation sensor 21, P180 estimate a local altimetric value A of the support table 5 relative to the upper end of the post 17 as a function of all the altimetric variation measurements VA, of a model of the supporting structure 3, and P130 determine an error value E resulting from a comparison of the local altimetric value A with a set value R.

[0134] Advantageously, the control circuit 41 is configured to carry out step P180 of the adjustment method.

[0135] Optionally, the supporting structure 3 does not include a distance sensor 25.

[0136] The embodiments can be combined with each other in any technically possible combination.

Claims

CLAIMS 1. Supporting structure (3), characterized in that it comprises: - a support table (5) supported by at least four posts (17), each post (17) carrying, at its upper end, a connecting member (19) connecting the support table (5) to the post (17), - at least four altimetric variation sensors (21), each altimetric variation sensor (21) being configured to measure the relative altimetric variation V of the support table (5), - a distance sensor (25) configured to measure the distance between the upper end of a reference post (27) and the support table (5), the reference post (27) being chosen from the posts (17), and - an adjustment system (37) configured to control the deformation of the support table (5), the adjustment system (37) comprising a set of actuators (39) such that each post (17) carries an actuator (39) arranged between the post (17) and the support table (5), the actuator (39) being configured to modify the distance between the post (17) and the support table (5) as a function of measurements from the altimetric variation sensors (21) and the distance sensor (25).

2. Supporting structure (3) according to claim 1, in which each altimetric variation sensor (21) is arranged closer to a post (17) than the other altimetric variation sensors (21).

3. Supporting structure (3) according to claim 2, in which each altimetric variation sensor (21) is positioned in line with a post (17), preferably arranged on the support table (5), under the support table (5), or in the thickness of the support table (5).

4. Supporting structure (3) according to any one of claims 1 to 3, in which the distance sensor (25) is positioned in line with the reference post (27).

5. Supporting structure (3) according to any one of claims 1 to 4, in which the set of actuators (39) is composed of hydraulic actuators, preferably hydraulic cylinders, more preferably double-acting hydraulic cylinders.

6. Supporting structure (3) according to any one of claims 1 to 5, in which the support table (5) supports a rotating machine (7), preferably a turbo-alternator group.

7. Supporting structure (3) according to any one of claims 1 to 6, in which each post (17) is made of reinforced concrete or steel.

8. Supporting structure (3) according to any one of claims 1 to 7, in which each post (17) has a height of between 10 meters and 30 meters, preferably a height of between 15 meters and 20 meters.

9. Supporting structure (3) according to any one of claims 1 to 8, in which the connecting member (19) comprises a spring-forming element.

10. Supporting structure (3) according to claim 9, wherein the spring-forming element comprises at least one spring box (29) interposed between the post (17) and the support table (5), preferably between three and six spring boxes (29) interposed between the post (17) and the support table (5).

11. Supporting structure (3) according to any one of claims 1 to 10, in which the adjustment system (37) comprises a control circuit (41), the control circuit (41) controlling the set of actuators (39) from measurements of the altimetric variation sensors (21), the distance sensor (25) and a preference setpoint defined by a user.

12. Supporting structure (3) according to any one of claims 1 to 11, in which each altimetric variation sensor (21) is an H LS sensor.

13. Power plant (1) comprising a supporting structure (3) according to any one of claims 1 to 12, preferably the power plant (1) being a nuclear power plant or a thermal power plant.

14. Method for adjusting a supporting structure (3) according to any one of claims 1 to 12, which comprises the following steps: - P100 measure the relative altimetric variation V by each altimetric variation sensor (21), - P110 measure the distance D by the distance sensor (25), - for each post (17), P120 determine a local altimetric value A of the support table (5) at the post (17) relative to the upper end of the reference post (27) as a function of the measurement of the relative altimetric variation V carried out by the altimetric variation sensor (21) closest to the post (17) and of the measurement of the distance D carried out by the distance sensor (25), and P130 determine an error value E resulting from a comparison of the local altimetric value A with a set value R, - for each post (17), from the error value E, P140 controls the actuator (39) carried by the post (17), so as to minimize the error value E relating to each altimetric variation sensor (21).

15. Adjustment method according to claim 14, which further comprises the following steps: - P150 input a CC correction instruction by means of the user interface (47), the CC correction instruction being a function of at least one value of the support table (5) chosen from a deformation value, a roll value, a pitch value and an altimetric displacement value preferably relative to the reference post (25), and optionally the predetermined minimum value Cmin and the predetermined maximum value Cmax, - depending on the CC correction instruction and for each post (17), P160 calculates a reference value R for the actuator (39) carried by the post (17).

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