FR2797531A1 - ELECTRICAL ENERGY SUPPLY NETWORK, ESPECIALLY PUBLIC LIGHTING - Google Patents

Abstract

The invention concerns an electric power supply network, such as a public lighting network, in particular light poles, using an electric cable. Said network comprises at least an active electric conductor (Ph1, Ph2, Ph3) and consisting of several interconnected sections in series to sites for connecting said equipment. The invention is characterised in that the voltage booster means (E) are mounted in series on the active conductor (Ph1, Ph2, Ph3) of the cable (A) so as to prevent the voltage at one of said sites to fall below a predetermined value. The invention is useful for electric power supply networks.

Description

The invention relates to an electrical energy supply network, such as a public lighting network, of equipment, in particular of candelabras, by means of an electrical cable comprising at least one active electrical conductor and formed by a plurality sections interconnected in series at connection locations for said equipment.

In the field of low voltage electrical distribution networks, in particular public lighting networks, the standards in force recommend limiting the voltage drop between the origin of the installation supplied with energy and the part farthest from its origin to a predetermined maximum value. For example, in public lighting, in order to allow the ignition of the lamp furthest from the power supply station, this voltage drop must be limited depending on the type of installation to 3% or 5% . The standards also require protection of the conductors against the effects of an abnormal increase in current liable to cause overheating harmful to the insulation of the conductors.

To comply with these normative constraints, the installers oversize the section of the cables of the supply networks. This oversizing of the cables generates a significant additional cost for the networks.

Figure 1 shows a public lighting network of this type. A cabinet or a station 1 connected to a low voltage electrical energy source supplies by means of a cable A three candelabra C1, C2, C3 ... of an installation. Each candelabrum comprises a connection box B of a lamp L to the cable A. A first section A1 of the cable A electrically connects the station 1 to the connection box B1 of the first candelabra C1. This box B1 ensures both the electrical connection of the candelabra Cl to the cable A1 and the connection to the section A2 supplying the candelabrum C2. A cable feeds the lamp of the candelabrum.

In Figure 1, cable A is a three-phase cable with a neutral conductor. Each of the conductors is of large section. To balance the network phases, the candelabras C1, C2, C3 are connected, alternately, to one of the network phases. The latter comprises a protection K, arranged in the cabinet 1 and produced by a fuse or a three-phase circuit breaker. This protection is calibrated to protect cable A over its entire length. As shown in Figure 2, each box B1 to B3 includes an individual protection device P, such as a fuse or circuit breaker. The box has four terminals Bphn, namely Bph1, Bph2, and Bph3 for the neutral conductor N and the three phase conductors PH1, PH2 and PH3. It can be seen that the protection device P is mounted in bypass.

 Since the networks are often very long, the cables A are of large section to limit the voltage drops in line so that the last candelabra of the installation has a sufficient supply voltage. Protection K is calibrated to avoid excessive heating of the cables over their entire length. Protection K must be activated even if a short circuit is caused at the end of the line near the last candelabra. As the drop in line voltage limits the intensity of the short circuit, it is necessary, according to standards, that for a given section of cable conductors, the total length of cable A does not exceed a certain value. In practice, this distance makes it necessary to over-calibrate the sections of the conductors with respect to what would be sufficient relative to their heating for the transport of the electrical energy consumed by the installation. In the event of a short circuit caused on a line, protection K is triggered, causing the complete extinction of the network, which is contrary to the objective of safety in public lighting which is to ensure maximum service continuity.

The object of the present invention is to propose an electrical energy distribution network which overcomes the disadvantages which have just been stated, known networks.

To achieve this aim, the distribution network according to the invention is characterized in that voltage-raising means are mounted in series on the cable conductors at at least one of the sections, so as to prevent the tension in end of the cable drops below a predetermined value.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating an embodiment. of the invention and in which - Figure 1 is a schematic view of a known electrical energy distribution network; - Figure 2 is an enlarged view of part II of Figure 1; - Figure 3 is a schematic representation of an energy distribution network according to the present invention; - Figure 4 shows a candelabra equipped with a connection box according to the invention; - Figure 5 is a perspective view of a connection box according to the invention; - Figure 6 is a perspective view of a connection terminal device according to the invention; - Figure 7 is a diagrammatic view of a first embodiment of a voltage raising device according to the invention; - Figure 8 is a schematic view showing a second embodiment of the voltage raising device according to the invention; - Figure 9 is a schematic view of a third embodiment of a voltage raising device according to the invention; - Figure 10 shows a candelabra equipped with an improved cabinet device of the invention; and - Figure 11 is a schematic view of a fully electronic embodiment of a voltage raising device according to the invention.

FIG. 3 shows, by way of example of the invention, a three-phase public lighting network according to the invention, which comprises fifteen candelabras each equipped with a lamp respectively L1 to L15 and supplied with low voltage electrical energy from of a cabinet 1. The lamps are mounted as a shunt between a phase conductor Phi, Ph2 or Phi and the neutral conductor N of cable A. In Figure 3, the lamps L1, L4, L7, L10 and L13 are connected to the Phi phase, the L2, L5, L8, L11 and L14 lamps on the Ph2 phase and the L3, L6, L9, L12 and L15 lamps on the Phi phase, current is returned by the neutral conductor N. Des segments x1, x2, x3 ... represent the distance between two adjacent candelabras.

The peculiarity of the network according to the invention lies in the fact that, in order to reduce the cross section of the conductors of the cable A or to allow a higher power to be transported in the network, voltage boosters E are arranged in series in each of the conductors at predetermined locations, namely the devices E1 and E4 in the conductor Phi, the elevating devices E2 and E5 in the phase conductor Ph2 and the devices E3 and E6 in the phase conductor Phi. The devices E1, E2, E3 are located at a distance z1 from the last candelabrum connected to the phase conductors, namely respectively from the candelabras of the lamps L13, L14 and L15 while z2 indicates the distance respectively between the devices E1 and E4, E2 and E5 and E3 and E6.

Each phase conductor further comprises two protections F against overcurrents which are connected in series, in cascade one behind the other. The phase conductor Phi is provided with protections Fi and F4, F1 being arranged at a distance y1 from the last candelabra of the lamp L13 supplied by this conductor. Correspondingly, the two protections F2 and F5 of the conductor Ph2 and the two protections F3 and F6 of the conductor Phi are located at the distance y1 from the candelabra of the lamps L14 and L15 and at the distance y2 from each other. It should also be noted that the distribution station at the head of the network, namely the cabinet 1, is provided with protection K and with a voltage regulator R.

The number of voltage raising devices E and their location in each of the conductors is determined by calculation starting from the end of the network. The energy consumed by each of the candelabra lamps and the cross section chosen for the conductors of cable A will be calculated, depending on the minimum voltage admitted at the end of the network, the length z1 between the end and the candelabra where device E is to be placed. By carrying out this calculation, it turns out that in the phase conductor Phi the maximum admissible voltage drop according to the standards is reached at the candelabra of the lamp L9. A voltage raising device, namely the E1 device, will be mounted in the Phi conductor at this location. As will be explained below, the device E1 will be placed in the connection box B of the candelabrum, that is to say the box B9. The device E1 will make it possible to raise the downstream voltage to a value close to the predetermined constant voltage of the energy source, the lamp L13 of the last candelabrum supplied by the conductor Phi being supplied with a voltage compatible with its ignition as provided for in the standards. . The locations of the voltage raising devices E2 and E3 are calculated in the same way. I1 follows that the devices E2 and E3 identical to E1 must be placed in the boxes B10 and B11 of the lamps L10 and L11.

The same calculation will be applied to determine the location of the voltage raising device E4 upstream of the device E1. The calculation is made by considering that the voltage at the input of the device El must be compatible with the standards. In the case of the example shown in FIG. 3, it turned out that the voltage raising device E4 must be located at the level of the lamp candelabra L3. It will then be placed in the connection box B3 of this candelabrum in the Phi conductor. According to the same considerations, the lifting devices E5 and E6 will be placed respectively in the phase conductors Ph2 and Phi in the candelabras of the lamps L4 and L5. In order to limit the dimensions of the lifting devices E, given the small volume available for accommodating them inside the candelabra, it may be advantageous to regulate the network using the regulator R placed in the cabinet 1.

For the installation of electrical protections F, it is also determined by calculation. To this end, we start from the candelabrum which is located at the end of the cable, opposite the cabinet 1. For a given section of conductors, we evaluate the electrical energy consumed by the candelabras and by the cable A. line impedance downstream of the protection must not limit the current below a value which would prevent tripping of protection F which must also effectively protect the cable against excessive heating. Depending on the cross section chosen for each of the conductors Phi to Phi and N of cable A, the calculation makes it possible to determine the maximum number of candelabras that can be installed on one of the phase conductors Phi to Phi downstream of this protection. Assuming that the calculation shows that, for the chosen cross section of the Phi conductor, three candelabras can be properly protected, protection F1 such as a fuse will be placed on the Phi conductor upstream of the equipment consuming electrical energy, namely lamps L7, L10 and L13. The same calculation makes it possible to place protections F2 and F3 in the phase conductors Ph2 and Phi. The protections Fi, F2 and F3 will be installed in the connection boxes respectively B7, B8 and B9 of the candelabra of the L7, L8 and L9 lamps. After calculating the distance y1 separating the protections F1, F2 and F3 from the last candelabra C13, and C14, C15 corresponding, we calculate in the same way at distance y2 separating on the same phase the protection already placed from that to be placed upstream . In the example shown in FIG. 3, it has been found that, for the size of the conductors chosen, the number of lampposts to be protected cannot exceed two sections. The protections F4, F5, and F6 are then placed two candelabras upstream, that is to say in the candelabras of the lamps L4, L5 and L6.

In the example shown in Figure 3, each voltage raising device E is single-phase so as to have a reduced footprint allowing its easy installation in the connection box of a candelabra. Of course, one could also consider the use of a single three-phase voltage booster which will then be installed in one of the candelabras of the lamps L9, L10 or L11 and intended to fulfill by itself the functions of the three devices El, E2 and E3. Indeed, the devices El, E2 and E3 are crossed by a current intensity lower than those passing through the devices E4, E5 and E6.

The protections F1, F2, F3 or also F4, F5, F6 can also, if the calculation allows, be grouped into a single three-phase protection placed in a single candelabra. It should also be noted that provision should be made for selective triggering of the protections, so that a fault occurring downstream only causes the operation of the protection directly upstream.

Referring to Figures 7, 8 and 9, three different embodiments of a voltage-raising device E according to the invention are described. The device according to FIG. 7 with voltage transformer makes it possible to increase the input voltage. It is calibrated to read the voltage from a constant predetermined value corresponding to the maximum voltage drop value acceptable by standards. The devices shown in FIGS. 8 and 9 make it possible to regulate the output voltage as a function of a variable input voltage within certain limits. They can either raise the voltage to a value close to the nominal network voltage, or, optionally, lower the output voltage, in particular to reduce the energy consumption of the equipment, to favor the starting conditions of the installations or to have a constant voltage promoting the longevity of equipment, namely lamps.

More specifically, the voltage raising device E shown in FIG. 7 comprises a voltage transformer 10 comprising, mounted on the same carcass 11, a primary winding 12 of small section connected as a branch on the upstream section for example A1, namely the corresponding phase conductor Ph and the neutral conductor N, and an additional winding 13 of large cross-section in series in the phase conductor. The number of turns of the winding 12 serves as a voltage reference frame and is crossed only by a low current. The small cross section of the wire of the winding 12 makes it possible to limit its volume inside a candelabrum or in underground or overhead connection boxes. The fact that the winding 13 is of large cross section and that it only slightly raises the tension, it has only a few turns. Consequently, the transformer 10 has the advantage of being of a limited volume. Indeed, according to the above-mentioned regulations, the voltage booster E will be calibrated to increase the output voltage by 3 to 5% in addition to the input voltage, depending on the type of installation envisaged.

The voltage raising device as shown in FIG. 8 also comprises a voltage transformer 10, a carcass 11 and windings 12 and 13. The device comprises several output circuits comprising an increasing number of turns and individually actuable by means of electrical or electronic switches of triac or thyristor type 15 controlled by control electronics 16.

The voltage-raising device according to FIG. 9 is of the autotransformer type comprising a variable transformer 17 provided with two sliders 18, 19 mounted in the circuit of a secondary winding 20 of a transformer 21 whose primary winding 22 is mounted in series in the phase conductor Ph. The sliders 18, 19 make it possible to add or subtract a voltage from the upstream voltage so as to maintain the desired voltage at the output. The latter is regulated by an electronic controller 23 which also performs the overcurrent control function.

The voltage raising device E, in FIGS. 7, 8 and 9 comprises different protection means shown in FIG. 7. The protection device comprises a relay R1, one terminal of which is connected via a bimetal contact 25 to phase conductor Ph and the other terminal of which is connected to the neutral conductor N. This relay controls a certain number of contacts such as a break contact r11 disposed in the phase conductor Ph downstream of the winding 13, a contact normally open r13 intended to short-circuit the transformer 13 when it is closed as well as a contact r14 disposed between the phase conductor Ph and the terminal of the relay R1, which is connected to the bimetallic contact 25. The contact r14 is normally open . Finally, the relay also includes a contact r15 intended to close a circuit 27 of an acoustic vibrator and / or of a light-emitting diode of the LED type and / or of any other contact for signaling a fault.

The protection device also includes a relay R2 mounted downstream of the transformer 10 between the phase conductor Ph and the neutral conductor N. This relay controls a contact r21 normally closed and disposed between the terminal of the relay R1 which is connected to the bimetal contact 25 and the phase conductor Ph. This relay can also cause the excitation of relay R1 in the event of a lack of voltage at the output of transformer 10.

In fact, when the relay Ri is actuated, it keeps the contact r13 closed by virtue of the self-maintenance carried out by the closing of the contact r14, which is signaled using the contact r15. Thus, the protection device protects against faulty operation of the transformer, without stopping the installation downstream of the lifting device and allows signaling of faults to ensure maximum service continuity for a public lighting installation, even in the event of a lifting device failure. The faults of a voltage raising device E could be caused by the excessive heating detected by the bimetal contact 25 or a short circuit inside the windings detected by the relay R2. In both cases the transformer is short-circuited by contact r13. The defective voltage booster will not correct the downstream voltage and the last candelabra in an installation may not light up. This malfunction is less annoying for the user of an installation than the complete interruption of the installation part located downstream of the defective voltage booster E.

It should be noted that the transformer 10 has special characteristics, in particular with regard to the shape of its carcass 11 and the material of the sheets used for its manufacture, so as to reduce its external volume and allow it to be integrated into the interior of a candelabra.

Referring to Figures 4 and 5, there will be described below an advantageous embodiment of a connection box B according to the invention, itself housed inside a candelabra C and accessible by the hatch visit 29 of the candelabrum. The box encloses a voltage raising device E and a protection F made in the form of a fuse or circuit breaker.

The connection box B comprises two substantially identical terminal blocks 30, 31. Terminal block 30 is connected to the upstream cable section A1 and terminal block 31 to the downstream cable section A2. The protection device F and / or the voltage raising device E is mounted in series with the cable sections A1 and A2 between these two terminal blocks 30 and 31. Each terminal block comprises, on the other hand, a device for connecting the conductors 33 supply of the electrical equipment, namely the lamp L of the candelabrum, by means of a fuse or circuit breaker protection 34.

In the embodiment according to FIGS. 5 and 6, the terminal blocks 30 and 31 each comprise two or more terminals 36 placed side by side, which are parallelepipedal metal blocks, each of which is individually electrically connected to one of the connectors N, Phi at Phi of cable A. The voltage raising device E and the protections F and 34 are mounted on the housing fixing rails, which are indicated at 38.

Referring to Figure 6, we see that each terminal 36 has a cell 40 capable of receiving and inserting one of the connectors N, Phi to Phi, and a cell 41 for receiving a connector 42 for connection to a voltage raising device E and / or an electrical protection F, or of a connector going directly from the terminal block 30 to the terminal block 31, as well as a cell 43 allowing the connection in derivation of the cable 33 supplying the lamp L. The terminals 36 are housed inside the insulating box of the terminal block 30, 31, individually inside compartments 45, with a large clearance allowing them to move vertically relative as shown by the arrow.

The cell 40 of each of the terminals 36 opens out through a window 47 on the lower face 48 of the terminal block, and the cells 41 and 43 open on the upper face at 50 of the terminal block. The cells 40, 41 and 43 receive clamping screws respectively 51, 52 and 53, all accessible by the front face 55 of the terminal block. The insulating box is provided with mounting and locking means inside the box B such as hooking lugs 57 and / or a hooking system on fixing rails.

It should be noted that a terminal block 30, 31 shown in FIG. 6 is three-phase with neutral and includes four identical terminals 36 placed side by side in four insulated housings 45 of its housing, each of the terminals connecting individually to a neutral conductor and of phase of cable A. Of course, the terminal blocks could be unipolar or multipolar depending on the type of network. It appears from FIG. 5 that the lifting and protection devices E and F have the advantage of being able to connect in series with the network between the terminals 30 and 31 on one of the phases of the cable. Protection F could also be three-phase if the installer decided to put a single three-phase protection for all the phases of the cable in the same candelabra. I1 is the same for the voltage raising device E. The circuit 3 includes the protection 34 of the derivative circuit is connected between a phase, namely the phase Phl in FIG. 5 and the neutral conductor N. The arrangement of the terminal blocks 30 and 31 allows all the possibilities of connection in series or in diversion inside the box B, whatever the type of single-pole or three-pole connection.

The arrangement of the cells 41, 43 is advantageous for the electrical connection. In fact, the cells are open at the bottom to connect the conductors Ph of the cable coming from the ground while the cells 41 and 43 are open at the top to simplify the connection of the conductors 42 and 33.

FIG. 10 shows another mode of mounting the voltage raising device E in a candelabra C. According to this embodiment, the transformer 10 and its relays R1 and R2 are mounted on a support, a plate or a housing 63. The assembly can be fixed above the connection box B, either by being fixed on the roof 58 of the box or by being blocked by suitable hooking means inside the candelabra above the access door 29 , cables 60 ensuring that the device E is connected in series on the terminal blocks 30 and 31. In this location, the plate 57 is not accessible through the door 29. An light-emitting diode of the circuit 27 will be placed inside of the box to report any malfunction of the voltage raising device E and will be connected to this via a conductor 62.

The voltage raising device E must be able to operate outdoors for many years and therefore withstand severe climatic conditions. All components will meet these requirements. In particular, the transformer 10 will be sealed and favorably impregnated with a protective resin, the electronic parts other than those of connection being advantageously embedded in a solidified resin.

When powering up a public lighting network, it may be advantageous for each voltage-raising device E to supply the network placed downstream after a predetermined time so that each part of the network z1, z2 placed respectively downstream of the lifting devices for example E1, E4 in the Phi phase are energized one after the other, in a sequential manner, which has the advantage of gradually putting a network into service and limiting the intensities starting. To achieve this result and with reference to FIG. 7, each lifting device E will be equipped upstream with a delay relay 65 with adjustable delay after the appearance of the upstream voltage. During the ignition phase of an installation, the various electrical equipment placed downstream of the voltage raising devices E can be subjected to significant overloads for several minutes. The device E as shown in FIGS. 8 and 9 can also optionally reduce its output voltage to a predetermined value, in particular during certain periods of the night to limit the lighting and the energy consumed. To this end, the control electronics 16 or 23 will be controlled by a clock 30 shown in FIG. 8.

It is also advantageous to limit the variations in voltage of the source from the connection cabinet 1 so that the supply voltage of the entire network is precisely adjusted to the nominal voltage value of the source. I1 is then appropriate to place in the cabinet 1 where the station at the head of the installation a regulator R as shown in FIG. 3 which has the function of regulating the variations in network voltage. As generally these cabinets have a large internal volume, it is possible to accommodate a large size regulator regulating the entire network for the entire range of possible variations in the voltage of the energy source, so as to limit the importance of the regulation carried out by each of the voltage raising devices E housed in the candelabras. The E devices placed downstream only have to compensate for the line voltage drops.

The regulator R is favorably of the same type as that shown in FIG. 8. It can optionally include adjustment possibilities at a reduced voltage controlled by the clock so as to save energy during off-peak hours or to start the network under reduced tension. The regulator R has the advantage of avoiding any propagation of overvoltages along the network, which are harmful for the lighting lamps. The regulator R can advantageously be installed in association with voltage raising devices E of the type shown in FIG. 7, the manufacturing cost of which is reduced. In the case of installations not requiring a regulator R at the head, in particular in the case of the extension of an installation by a line comprising a few candelabras, the use of a voltage raising device E regulating this line is sufficient . It will then be advantageous to use a device E of the type shown in FIGS. 8 and 9, which regulate the voltage within a narrow adjustment range, which has the effect of protecting the lamps against overvoltages. Of course, numerous modifications can be made to the various devices of the networks according to the invention. Also, for example the voltage raising devices could be entirely electronic using the technique of cutting the current by transistor with the technique of modulation of the pulse width.

FIG. 11 illustrates a fully electronic embodiment of the lifting device E. This device comprises, mounted between a phase conductor Ph and the neutral conductor N, a rectifier 65, an adjustment circuit 66 and an inverter 67. The terminals input 68, 69 of the amplifier are connected respectively to the output terminals 70 of the neutral conductor and 71 of the Ph phase. The output terminal 71 is connected to output 72 of the amplifier, the other output 73 of which is connected to the input 74 of the inverter 67. The other input 75 of the latter is connected to the output terminal 70 of the rectifier 65. To the output terminals of the inverter are attached the pH phase and the neutral conductor N. In these circumstances, the voltage at the input of the inverter, between terminals 74 and 75 is equal to the sum of the output voltage U1 of the rectifier 65 between terminals 71 and 70 and the voltage U2 between the output terminals 73 and 72 of amplifier 66.

The voltage step-up device is designed so that, if the grid voltage is equal to or greater than its nominal value, the voltage U2 is equal to zero and the inverter's cutting system ensures that its output voltage is equal to the nominal value. On the other hand if the network voltage at the input of the rectifier 65 is lower than the nominal value, the adjustment circuit 66 comes into operation and generates a voltage U2 which, by adding to U1 makes it possible to obtain at the output of the inverter a sufficient voltage to supply the candelabrum in question.

 It should be noted that the number of candelabras in a public lighting system can be greater than 15 and of course the number of lift and protection devices could then also be greater depending on the calculation given above. Finally, the invention also applies to tree network structures.

Claims (10)

<U> CLAIMS </U> 1. Electric power supply network, such as a public lighting network, of equipment, in particular of candelabras, by means of an electric cable comprising at least one active electrical conductor and formed by a plurality of interconnected sections in series at the locations of the connections of said equipment, characterized in that voltage raising means (E) are mounted in series on the active conductor (Ph1, Ph2, Phi) of the cable (A) so as to prevent the voltage at one of said locations drops below a predetermined value. 2. Supply network according to claim 1, characterized in that electrical protection means (F) against overcurrents are mounted in series on the active conductor at said locations. 3. Supply network according to one of claims 1 or 2, characterized in that a voltage raising device (E1 E2; E3) is arranged in the predetermined active conductor at a location mentioned above such that the minimum voltage allowed in line end of the network is not less than a predetermined value and in that at least one other voltage raising device (E4; E5; E6) is provided at a location upstream of the first device if the voltage at the input of the first device was, in the absence of the second lifting device, less than a predetermined tension. 4. Supply network according to claim 3, characterized in that the voltage raising device (E) is adapted to produce an output voltage greater than its input voltage by a predetermined amount such as from 3 to 5 s . 5. Supply network according to one of claims 2 to 4, characterized in that the electrical protection means (F) are formed by fuses or rated circuit breakers and their number and arrangements along the predetermined active conductor are chosen for avoid excessive heating of the active conductor. 6. Supply network according to one of claims 3 to 5, characterized in that the voltage raising device (E) essentially comprises a voltage transformer (10) comprising, mounted on the same carcass (11), a winding primary (12) across which is applied the input voltage to be raised and an additional winding (13) in series with the primary winding, the high output voltage being generated between the output terminals of all primary windings and additional. 7. Supply network according to one of claims 1 to 5, characterized in that the voltage raising device (E) comprises a variable transformer (17) provided with means for increasing and decreasing the input voltage so as to obtain a desired voltage at the output. 8. Supply network according to claim 7, characterized in that the variable transformer (17) is provided with two sliders (18, 19) mounted in the circuit of a secondary winding (20) of a transformer (21) whose primary winding (22) is mounted in series in the pH phase conductor. 9. Supply network according to one of claims 6 to 8, characterized in that the voltage raising device (E) comprises self-protection means, without stopping the part located downstream. 10. Supply network according to one of claims 1 to 5, characterized in that the voltage raising device (E) is produced in the form of an electronic device comprising a voltage rectifier (65), an adjustment circuit (66) capable of adding a voltage (U2) additional to the output voltage (U1) of the rectifier and an inverter (67) producing from the voltage obtained by addition the output voltage. he. Supply network according to one of claims 2 to 10, characterized in that, in a public lighting network, the voltage raising device (E) is mounted in the connection box (B) of a candelabra ( C) in series with the upstream and downstream cable sections. 12. Supply network according to one of claims 2 to 11, characterized in that, in a public lighting network, the protection means (F) in the form of fuses or circuit breakers are mounted in the connection box B of a candelabra (C). 13. Supply network according to one of claims 11 or 12, characterized in that the voltage raising devices E and / or the protection devices (F) are connected in series between two independent terminal blocks (30, 31) inside the connection box (B), at least one of which comprises a branch for a cable (33) for supplying the equipment (L) of the candelabrum. 14. Supply network according to claim 13, characterized in that the terminal blocks (30 and 31) are identical. 15. Supply network according to one of claims 13 or 14, characterized in that each terminal block (30, 31) comprises one or more metal terminals (36) comprising, accessible through a window in the underside of the terminal block, at least one cell (40) for connection to a section of conductor of the network cable, and, accessible through windows in the upper face, at least one cell (41) for connection to the other section of cable d 'power supply and a socket (43) for connection to a power supply cable of an equipment (L). 16. Supply network according to claim 15, characterized in that the connections are ensured by means of clamping in the aforementioned cells, which are accessible in the front face of the terminal block. 17. Supply network according to claim 16, characterized in that the metal terminals are displaceable according to a certain clearance inside their cell. 18. Supply network according to one of claims 11 to 17, characterized in that a voltage raising device and / or a protection device are mounted on rails provided in the connection box. 19. Supply network according to one of claims 11 to 18 characterized in that the voltage raising device (E) is arranged in a candelabra above the connection box (B). 20. Network according to one of claims 2 to 19 characterized in that the voltage raising device (E) comprises delay means (65) allowing a sequential ignition of the equipment.