EP3596791A1

EP3596791A1 - System for supplying electrical energy to an on-board network of a submarine

Info

Publication number: EP3596791A1
Application number: EP18710079.7A
Authority: EP
Inventors: Nicolas Pierre; Cyrille GARANS; Dominique Bruneau
Original assignee: Naval Group SA
Current assignee: Naval Group SA
Priority date: 2017-03-16
Filing date: 2018-03-16
Publication date: 2020-01-22
Also published as: AU2018235015A1; AU2018235015B2; SG11201908433UA; FR3064124A1; KR102530250B1; KR20190131027A; FR3064124B1; WO2018167306A1

Abstract

This system, including energy storage means (1) based on lithium batteries and means (5, 10, 12) for distributing this energy to user loads, comprising means (9, 11, 14) for cutting off and isolating branches (13) for connection of the user loads in particular in the event of a short circuit, is characterized in that it includes means (17) for monitoring the evolution of the output current of the energy storage means in order to detect the occurrence of a short circuit in the network, means (6, 7, 8) for disconnecting the energy storage means from the rest of the network in the event of such a detection, means (16) for connection to the network, means (15) for generating a controlled short-circuit current, in order to trigger the operation of the cutoff and isolation means (14) associated with the short-circuited branch (13), so as to isolate the latter from the rest of the network, means (16) for disconnecting the short-circuit current generator (15) from the network, and means (6, 7, 8) for reconnecting the electrical energy storage means to the rest of the network.

Description

ELECTRIC POWER SUPPLY SYSTEM OF A POWER SUPPLY NETWORK

EDGE OF A SUBMARINE

The present invention relates to a system for supplying electrical energy, in particular an onboard network of a submarine.

More particularly, the invention relates to such an electrical power supply system which comprises means for storing electrical energy based on lithium batteries.

These electric power supply systems also comprise means for distributing this electrical energy to user loads, these energy distribution means comprising means for breaking and isolating the connection branches of the charging charges. network user, especially in the event of a short circuit thereof.

In a traditional way, the means for storing electrical energy for this type of application, for example for submarines, have been based on the use of lead-acid batteries.

The protective devices of the network were then sized to be able to cut short circuit currents for example of this type of battery, these currents can for example be up to 50 kA.

However, the current trend is to use lithium batteries and in particular lithium-ion batteries, as electrical energy storage means for the type of applications envisaged.

However, the short-circuit currents of such lithium-ion batteries are much higher than the short-circuit currents of lead-acid batteries.

For example, values of 300 kA, that is to say values six times higher than the short-circuit currents of lead-acid batteries, are cited.

This raises the question of how to cut or interrupt such short-circuit currents with previously designed network protection devices.

The Applicant has already proposed reducing the short-circuit current in the event of an internal or external fault by inserting into the power line of each branch in parallel constituting the electrical energy storage system, for example a current chopper.

This chopper then makes it possible to limit the output current of each branch to a value parameterized in advance. Thus the short-circuit current is limited to a value compatible with the characteristics of the protective devices of the network to which the battery is connected.

However, the development of this type of chopper system is complicated by the need for coordination between the different choppers of the different branches and knowledge of the impedance downstream of the chopper for proper operation of the solution.

Other solutions have been proposed, for example in document EP 1 641 066.

In this document, it is proposed to make the battery per branch in order to limit the short-circuit current.

The basic concept of this structure is to limit the short-circuit current by connecting only a limited number of branches.

This document then proposes a system for managing branch connections and disconnections and battery charging.

This system requires a discharge circuit and a load circuit decoupled for example by diodes.

In addition, it imposes a complex management of the capacities of the different branches of the battery during charging and discharging.

This management requires very precise knowledge of the load states of the branches to avoid excessive exchange currents between branches when connecting and disconnecting them.

Now the precise knowledge of the state of charge of a lithium battery is not simple.

Another solution for limiting and breaking short-circuit currents for high-capacity lithium batteries, especially for submarine applications, was also presented in 2013.

This system proposes to insert, in the event of a fault on the network, a resistance in the power line of the branches of the battery to attenuate the value of the current by dissipating a high heat energy.

A system of static switches for example semiconductor, deflects the current in this resistance in case of overcurrent detected at the output of the branches of the battery.

This system requires a water cooling device and requires a complete study of the protection and selectivity plan of the electrical network of each type of submarine where it is installed, in order to define the value of the resistance that will allow limit the short-circuit current to a value allowing the operation of the electrical protection systems of the network.

Such a solution is described for example in the document WO 2010/089338.

Thus, these various solutions are based on a limitation of the output current of the branches of the battery in order to ensure the protection of the network and the selectivity of the network in the event of a fault, this limitation making it possible to ensure a value of current supplied by the battery compatible with the characteristics of network protection devices.

But we have seen that such systems are complex and complicated to put or point and implement.

The object of the invention is therefore to solve these problems.

To this end, the subject of the invention is a system for supplying electrical energy, in particular an onboard network of a submarine, of the type comprising means for storing electrical energy based on lithium batteries and means for distributing this electrical energy to user loads, these distribution means including means for breaking and isolating connecting branches of the user loads, particularly in the event of a short-circuit thereof, characterized in that it comprises:

means for monitoring the evolution of the output current of the electrical energy storage means in order to detect the appearance of a short circuit in the network,

means for disconnecting the electrical energy storage means from the rest of the network in the event of such detection,

network connection means, means for generating a controlled short-circuit current, for triggering the operation of the cutoff and isolation means associated with the short-circuited branch, in order to isolate it from the rest of the network,

means for disconnecting the short-circuit current generator from the network, and

means for reconnecting the electrical energy storage means to the rest of the network.

According to other features of the system according to the invention, taken alone or in combination:

the means for monitoring the evolution of the current delivered by the electrical energy storage means comprise means for analyzing the variation of this current over time in order to detect the appearance of a short circuit as soon as this variation exceeds a predetermined threshold; - The electrical energy storage means comprise a plurality of branches in parallel, each of which comprises disconnection means;

- The battery disconnecting means comprise controlled semiconductor switching devices;

the controlled semiconductor switching devices comprise MOSFET transistors;

the means for breaking and isolating the connecting branches of the user loads comprise circuit breakers;

the distribution means comprise at least one battery panel, at least one main panel and at least one secondary electrical energy distribution panel, connected between the energy storage means and the user loads;

it furthermore comprises means for measuring the isolation of the remainder of the network after disconnection of the energy storage means, to avoid reconnecting these storage means to the network, in the event of detection of an insulation fault of the network .

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

FIG. 1 represents the general structure of part of a system for supplying electrical energy, in particular an onboard network of a submarine; FIGS. 2 to 7 illustrate the operation of such a system; according to a first embodiment, and

- Figures 8 to 16 illustrate the operation of such a system according to a second embodiment.

It has in fact shown in Figure 1, a system for supplying electrical energy including an onboard network of a submarine.

This comprises means for storing electrical energy based on lithium batteries, designated by the general reference 1.

In fact, these energy storage means comprise several battery branches in parallel, designated by the general references 2, 3 and 4, for example in this FIG.

Each of these branches is connected to a battery panel designated by the general reference 5, through connection / disconnection means, respectively 6, 7 and 8.

As will be described in more detail below, these connection / disconnection means comprise, for example, semiconductor switching devices. controlled conductors, such as for example MOSFET transistors, inserted in the branches.

Of course, other semiconductor switching devices can be envisaged.

The battery table 5 also comprises a circuit breaker designated by the general reference 9.

This battery board 5 is connected to at least one main electric power distribution board, one of which is designated for example by the general reference 10 in this FIG.

This main electrical power distribution panel 10 also comprises for example several power supply branches, each of which also comprises a circuit breaker.

Thus a branch is illustrated in this figure and it comprises a circuit breaker designated by the general reference January 1 in this figure.

This power supply branch makes it possible to connect this main electrical energy distribution board 10 to at least one secondary electric power distribution board, one of which is designated for example by the general reference 12 in this figure.

This secondary electric power distribution board 12 supplies user load connection branches, for example the branch designated by the general reference 13 in this figure, through branch breaking and isolation means, comprising: also for example a circuit breaker, designated by the general reference 14.

A short-circuit generator, designated by the general reference 15, is connected to the battery board 5, through switch-shaped connection means, designated by the general reference 16 in this figure, controllable on closing and on opening to connect or disconnect this generator 15 from the battery board 5.

Such a power supply structure is then relatively conventional insofar as the electrical energy storage means comprise lithium battery branches, connected to a battery panel, itself connected through a main and secondary table cascade. distribution, to user load connection branches.

Each of these tables comprises means of cut-off and isolation for example based circuit breakers, which are then calibrated according to their location in the power supply, to cut the corresponding branch and isolate it from the rest of the network.

Unlike systems of the state of the art, which proposed to limit the value of the short circuit current at the output of the battery system, in the system according to the invention, it is proposed to disconnect the battery before it has reached its maximum value of short circuit current.

Cutting means comprising semiconductor devices are used for this purpose.

To illustrate the problem mentioned above concerning the value of the short-circuit current of lithium batteries, one can take as an example the case of a parallelization of several battery packs for applications of several hundred kilowatts / hour.

The short circuit current of the system can reach extremely important values.

For example if we consider fifty parallel battery packs each of which can provide 4 kA, this results in a short circuit current of the system of the order of 20 kA.

Conventionally, a DC fuse according to current technologies has a breaking capacity of only 100 kA maximum and must be changed after melting, which, in the applications mentioned, is not conceivable or at least not is not acceptable, for reasons of accessibility and rapid availability of energy after a fault.

Similarly, a DC circuit breaker, which can be reset, also has a breaking capacity of the order of 100 kA maximum according to current technologies.

Thus these systems are not designed to be able to cut short-circuit values beyond this value.

This is the reason why the invention proposes to act before the short-circuit current has reached its maximum value.

This makes it possible to limit the short-circuit current below the values acceptable by the circuit breaker (s) or fuse (s) as described, to guarantee the opening of the circuit while remaining in the zone in which the protective equipment is able to interrupt current.

Another aspect to take into account when dimensioning the protection of such a circuit, and in particular the calibration of the circuit breakers, is the selectivity of the different elements of the whole chain or the cascade of circuit breakers or fuses of the electrical distribution of the system.

For this, the short-circuit current must be controlled.

In particular, it should not be limited too low, otherwise some circuit breakers open too slowly, or even not open at all, which would be dangerous for the protection of the network in general and the various components of it. in particular.

Neither should the battery pack limit the short-circuit current to such a level that it does not trip the downstream protection of the electrical distribution in the network, otherwise the entire installation will be totally in default for any local fault.

For this purpose, the power supply system according to the invention uses means for monitoring the evolution of the output current of the electrical energy storage means in order to detect the occurrence of a short circuit in the network.

In particular, these monitoring means analyze the variation of this current in time to detect a crossing of a trigger limit threshold characteristic of a short-circuit fault, for example.

These monitoring means are designated by the general reference 17 in FIG.

These current monitoring means are then used to trigger the operation of the various means and protection members of the system and the network, in order to ensure the overall protection of the network, the selectivity of the tripping and the provision of electrical energy of optimally what is important for this type of applications.

FIGS. 2 to 7 show a first embodiment of such a system.

These figures 2 to 7 show the various elements that have already been described with reference to FIG.

When a fault occurs on one of the user load branches such as for example the branch 13, as illustrated in FIG. 2, the means 17 for monitoring the evolution of the output current of the means electrical energy storage, detect the appearance of this fault and in particular a short circuit in the network.

This monitoring is a fact for example an analysis of the variation of the current in time conventionally. In response to this detection of this short circuit, the system triggers the disconnection of the electrical energy storage means from the rest of the network, by opening the semiconductor switching devices 6, 7 and 8, as illustrated in FIG. figure 3.

Once these semiconductor switching members open, the system connects to the network and more particularly to Table 5, the short-circuit generation means 15, as shown in FIG. 4, by closing the connection means 16.

As indicated above, these generation means are adapted to cause a controlled short-circuit current, to trigger the operation of the cut-off and isolation means associated with the branch in short-circuit fault, in order to isolate it from the rest of the network, as shown in Figure 5.

Indeed, the chain or cascade network protection circuit breakers, located at different levels thereof, is designed and calibrated to obtain the selectivity mentioned above, opening branches in default as the branch 13.

This then makes it possible to isolate the branch and the fault relative to the rest of the supply circuit.

Once this fault is isolated, the system opens the means 16 for connecting the short-circuit generator to disconnect it from the network.

The circuit breaker 14 of the faulty user load branch for example 13 being open, it is then possible to reconnect the battery to the network to make the electric power available again, by closing the semiconductor switching members 6, 7 and 8, as illustrated in FIG. 7.

This restores the power supply to the network with the exception of the branch 13 in default.

It is conceivable that such a structure has a number of advantages.

Indeed, by monitoring the evolution of the output current of the electrical energy storage means, and in particular by analyzing the variation of this current in time to detect the occurrence of a short circuit, as soon as this variation exceeds a predetermined threshold, it is possible to anticipate the operation of the security and protection means of the network.

In response the system causes the disconnection of the battery at first. Then the short circuit generation means are connected to the network to cause the tripping of the protection circuit breaker of the faulty user load branch.

This makes it possible to isolate this defect from the rest of the network.

The short-circuit generator is then disconnected from the network and it is possible to reconnect the battery to this network to make electrical energy available.

FIGS. 8 to 16 illustrate an alternative embodiment of this system, which furthermore incorporates means 20 for measuring the insulation of the remainder of the network after disconnection of the electrical energy storage means, in order to avoid dimensioning the means 16 so that they can withstand the short-circuit current of the generation means 15, on closing.

The general operation of this embodiment of the system according to the invention is very close to that which has been described above.

Indeed, when the appearance of a fault is detected, FIG. 8, the system disconnects the battery from the network, FIG. 9.

Then, as shown in FIG. 10, the system opens the circuit breaker 9 of the battery panel 5, to enable, FIG. 11, the means 20 to measure the isolation of the rest of the network and to determine whether it is possible or not. continue the process of isolating the defect as described.

If this is the case, in FIG. 12, the short-circuit generator 15 is connected to the network by the means 16 and the circuit breaker 9 of the battery panel 5 is closed, FIG. 13.

This then makes it possible to cause the opening of the circuit breaker associated with the faulting branch as shown in FIG. 14, to isolate it from the rest of the network.

The disconnection of the short-circuit current generator is illustrated in the figure

15 and the reconnection of the battery in FIG.

It is thus conceivable that in the system according to the invention, semiconductor means based on MOSFET transistors for example, at the output of each branch of the battery, the function of which is to open rapidly for example in a less than 100 microseconds, in case of detection of too much current rise.

This then allows the battery to be disconnected before the battery has established its short circuit current rating.

A short-circuit current generator is then connected to the network.

Its function is to provide the short-circuit current sufficient to eliminate the short circuit by opening the protection equipment of the faulty branch. Once the fault is eliminated, the short-circuit current generator is isolated from this network and the battery is reconnected to the network.

Different technologies of short-circuit current generators can be envisaged, for example an electromechanical technology.

The connection means of the short-circuit current generator may also be based on controlled semiconductor switch technology.

Of course other embodiments can be envisaged.

Claims

1. - System for supplying electrical energy, in particular an onboard network of a submarine, of the type comprising means (1) for storing electrical energy on the basis of lithium batteries and means (5, 10, 12) of distribution of this electrical energy to user loads, these distribution means comprising means (9, 1 1, 14) for cutting and isolating branches (13) for connecting the user loads in particular in the event of a short-circuit thereof, characterized in that it comprises:

means (17) for monitoring the evolution of the output current of the electrical energy storage means in order to detect the appearance of a short circuit in the network,

means (6, 7, 8) for disconnecting the electrical energy storage means from the rest of the network in the event of such detection,

- means (16) for connection to the network, means (15) for generating a short-circuit current controlled, to trigger the operation of the means (14) of cutoff and isolation associated with the branch in short- circuit (13), in order to isolate it from the rest of the network,

means (16) for disconnecting the short-circuit current generator (15) from the network, and

means (6, 7, 8) for reconnecting the electrical energy storage means to the rest of the network.

2. - Power supply system according to claim 1, characterized in that the means (17) for monitoring the evolution of the current delivered by the electrical energy storage means comprise means for analyzing the variation of this current. current in time to detect the occurrence of a short circuit as soon as this variation exceeds a predetermined threshold. 3.- power system according to claim 1 or 2, characterized in that the means (1) for storing electrical energy comprise several branches in parallel (2,

3, 4), each of which includes disconnection means (6, 7, 8).

4. Power supply system according to any one of the preceding claims, characterized in that the disconnecting means (6, 7, 8) of the battery comprise controlled semiconductor switching devices.

5. A power system according to claim 4, characterized in that the controlled semiconductor switching devices comprise MOSFET transistors.

6. A power system according to any one of the preceding claims, characterized in that the means for breaking and isolation of the connection legs of the user loads comprise circuit breakers (14).

7. Power supply system according to any one of the preceding claims, characterized in that the distribution means comprise at least one battery board (5), at least one main board (10) and at least one secondary board ( 12) of electrical energy distribution, connected between the energy storage means and the user loads.

8. Power supply system according to any one of the preceding claims, characterized in that it further comprises means (20) for measuring the insulation of the rest of the network after disconnection of the energy storage means, for avoid reconnecting these storage means to the network, in case of detection of a network isolation fault.