WO2020002669A1 - Method for protecting a network capable of being isolated from a main network - Google Patents

Abstract

The present invention concerns a method for protecting a network capable of being isolated from a main network, said network comprising: - a device for producing static electricity supplying the network; - a start protection suitable for switching off the portion of the network downstream from said protection as a function of the value of current passing through it; - an electricity consumption load downstream of the start protection; - a means for adjusting the start protection suitable for adjusting, in time and in intensity, a magnetic and/or thermal triggering threshold of said start protection; said method comprising the configuring of the adjustment means such that the threshold characteristics of magnetic and/or thermal triggering threshold of the start protection are lower than a curve of time vs. current passing through the protection, representing the characteristic in overload of the device for producing static electricity.

Description

 METHOD FOR PROTECTING A NETWORK LIKELY TO BE ISOLATED FROM A

 MAIN NETWORK

FIELD OF THE INVENTION

 The present invention relates to a method of protecting a network capable of being isolated from a main network, in particular when in an isolated mode, the supply of electricity is carried out by static generators.

 The present invention also relates to a network protection system implementing such a method.

STATE OF THE ART

 Some isolated places like islands or mountainous areas have electrical networks which are or may be isolated from a public network (or main network). They can be isolated from it permanently, as in the case of an island not electrically connected to the mainland, or temporarily, for example following an incident on the electricity supply lines during difficult weather situations.

 In the event of isolation, local energy resources, sometimes associated with storage, can be used to maintain electricity production in the isolated network.

 These power supply networks, called microgrid type electrical networks, can be supplied with electricity by so-called “static” generators, that is to say composed of static switches, in the sense that they make it possible to switch an electric current without recourse to mechanical or electromechanical elements, more commonly called inverters. This is particularly the case for storage by electrochemical battery connected to the network by a static generator.

 The context of protection of electrical micro-grids when they are powered by static generators and not by rotating generators is a known problem. However, there is no generic method to determine the protection plan.

 For networks which are not electrical micro-networks, that is to say interconnected networks and networks supplied by rotating generators such as diesel generators, those skilled in the art have methods known for development of a protection plan.

 For these networks, there are two major characteristics:

First, the sources of production and the supply networks can be modeled by linear electric models composed of voltage sources, resistances, inductances and capacitances. Those skilled in the art have calculation methods for calculating the short-circuit currents necessary for the preparation of the protection plan. This is the object, for example, of standard IEC 60909. Furthermore, concerning high and low voltage networks, it is considered in the development of protection plans that the supply networks located upstream can supply a fault as much time as necessary. In the case of synchronous groups supplying a network disconnected from the main network, the time periods known as “sub transient”, “transient” and “synchronous” are known in which the person skilled in the art has elements allowing him to do calculations of short-circuit currents at different times after the short-circuit.

In the case of an electrical micro-network powered by static generators, there is no method for calculating short-circuit currents. In fact, the static generators used to power electrical micro-grids are not linear. The means known to those skilled in the art is to carry out temporal simulations.

 In addition, in the general case, static generators have a contribution to the short-circuit current more than three times lower than a synchronous generator or a power supply. As a result, certain protections that can be used outside of electrical micro-networks are no longer used in the context of an electrical micro-network because the currents are too low.

 Also, in the general case, the static generator can only supply current greater than its nominal current for a few hundred milliseconds. Often the manufacturer of the static generator specifies its overload current capacity (OCC) in English which determines the duration during which the generator can deliver a current higher than its nominal current, for example 120% for 10s, 150% for 2s and 200% for 200 ms.

 Thus, those skilled in the art are unable to establish a protection plan in the context of electrical micro-grids.

 In addition, in the case of networks which can be supplied either with a synchronous group or a supply network, or with a static source, the person skilled in the art has no guarantee that the protections in place will be well functional in micro-grid type power supply.

STATEMENT OF THE INVENTION

The invention aims to overcome the drawbacks of the prior art described above. In particular, an object of the invention is to propose a method for protecting a network capable of being isolated from a main network, said network comprising:

 a device for producing static electricity supplying the network;

 at least one starting protection adapted to put the portion of the network, downstream of said protection, de-energized as a function of the current value passing through it; at least one load of electricity consumption downstream of the departure protection;

 at least one means of adjusting the starting protection adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection;

the device for producing static electricity, when it supplies the network in an isolated configuration, having an overload gauge which determines, for several values of current greater than its nominal current, the duration during which the device for producing static electricity can deliver this current without disconnecting, depending on the current delivered, said method being characterized in that it comprises the steps of:

 determination of a simulation model describing the behavior of the device for producing static electricity on a defined network;

 - simulations of single-phase, two-phase and three-phase short-circuits at each network node (100) downstream of the protection to determine a set of points Generator current / Start protection current, corresponding respectively to:

 o greatest currents, among the currents of each phase, delivered by the device for producing static electricity and

 o greatest current among the currents of each phase passing through the flow protection (105) upstream of the node on which the short-circuit was made;

and from the values of Static generator current as a function of the overload mask;

 determination of a time / current curve crossing the protection, which represents the overload characteristic of the device for producing static electricity on the network from which said device for producing static electricity is likely to disconnect from the network; and

configuration of the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection are less than the time / current curve. Advantageously, but optionally, the system according to the invention can also comprise at least one of the following characteristics:

 the step of determining the temporal model includes simulations of single-phase, two-phase and three-phase short circuits at each node of the network downstream of the protection;

 the magnetic and / or thermal trip threshold characteristics of the starting protection are lower, by at least a predefined time margin, than the time / current curve (current passing through the protection) which represents the overload characteristic of the static electricity production;

 the load also includes a connection circuit breaker capable of opening to disconnect said load from the network, said circuit breaker being characterized by a tripping curve which determines its opening time as a function of the current value passing through it; and in which the magnetic and / or thermal trigger threshold characteristics of the starting protection are greater, by at least a predefined time margin, than the trigger curve;

 the preset time margin is around 100 ms.

 the method also includes a predefined Imax value associated with each portion of the network downstream of the outgoing protection, said Imax value corresponding to the maximum current that can be called by said outgoing; and in which the magnetic and / or thermal trip threshold characteristics of the initial protection are greater, by at least a 10% intensity margin of Imax, than Imax;

 the process also includes:

 o the determination of a minimum short-circuit current value Iccmin for each set of load connection nodes downstream of a starting protection;

 o obtaining a maximum elimination time for a predefined network fault Tmax; and in which the thermal tripping threshold characteristics of the starting protection are lower in time and in intensity than Tmax and Iccmin;

The subject of the invention is also a system for protecting a network capable of being isolated from a main network, said network comprising:

a device for producing static electricity supplying the network; at least one starting protection adapted to put the portion of the network, downstream of said protection, off according to the value of current flowing through it; at least one load of electricity consumption downstream of the starting protection;

 at least one means of adjusting the starting protection adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection;

the device for producing static electricity, when it supplies the network in an isolated configuration, having an overload gauge which determines, for several values of current greater than its nominal current, the duration during which the device for producing electricity can deliver this current without disconnecting, depending on the current delivered, said system being characterized in that it comprises at least:

 a means of determining a simulation model describing the behavior of the device for producing static electricity on a defined network;

 a means of simulating single-phase, two-phase and three-phase short-circuits at each node of the network downstream of the protection to determine a set of static generator current / starting protection current points, corresponding respectively to:

 o greatest currents, among the currents of each phase, delivered by the device for producing static electricity and

 o greatest current among the currents of each phase passing through the outgoing protection upstream of the node on which the short-circuit was made; a means of determining, from the values of static generator current and as a function of the overload gauge, a time / current curve crossing the protection, which represents the overload characteristic of the device for producing static electricity on the network to from which said electricity production device is capable of disconnecting from the network; and

 a means for configuring the adjusting means such that the magnetic and / or thermal trip threshold characteristics of the starting protection are less than the time / current curve.

The subject of the invention is also a network capable of being isolated from a main network, said network comprising:

a device for producing static electricity supplying the network; at least one starting protection adapted to put the portion of the network, downstream of said protection, off according to the value of current flowing through it; at least one load of electricity consumption downstream of the starting protection; at least one means of adjusting the starting protection adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection;

the device for producing static electricity, when it supplies the network in an isolated configuration, having an overload gauge which determines, for several values of current greater than its nominal current, the duration during which the device for producing electricity can deliver this current without disconnecting depending on the current delivered, said network being characterized in that it comprises at least:

 a means of determining a simulation model describing the behavior of the device for producing static electricity on a defined network;

 a means of simulating single-phase, two-phase and three-phase short-circuits at each node of the network downstream of the protection to determine a set of static generator current / starting protection current points, corresponding respectively to:

 o greatest currents, among the currents of each phase, delivered by the device for producing static electricity and

 o greatest current among the currents of each phase passing through the outgoing protection upstream of the node on which the short-circuit was made; a means of determining, from the values of static generator current and as a function of the overload gauge, a time / current curve crossing the protection, which represents the overload characteristic of the device for producing static electricity on the network to from which said electricity production device is capable of disconnecting from the network; and

 a means for configuring the adjusting means such that the magnetic and / or thermal trip threshold characteristics of the starting protection are less than the time / current curve.

The subject of the invention is also a device for configuring protection of the start of a network capable of being isolated from a main network, said start protection being adapted to put the portion of the network, downstream of said protection, out voltage as a function of the current value flowing through said network comprising:

a device for producing static electricity supplying the network; at least one load of electricity consumption downstream of the starting protection;

 at least one means of adjusting the starting protection adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection;

the device for producing static electricity, when it supplies the network in an isolated configuration, having an overload gauge which determines, for several values of current greater than its nominal current, the duration during which the device for producing electricity can deliver this current without disconnecting depending on the current delivered, the starting protection configuration device being configured to:

 determine a simulation model describing the behavior of the device for producing static electricity on a defined network;

 - simulate single-phase, two-phase and three-phase short-circuits at each node of the network downstream of the protection to determine a set of static generator current / start protection current points, corresponding respectively to:

 o greatest currents, among the currents of each phase, delivered by the device for producing static electricity and

 o greatest current among the currents of each phase passing through the outgoing protection upstream of the node on which the short-circuit was made; determine, from the values of Static generator current and as a function of the overload template, a time / current curve crossing the protection, which represents the overload characteristic of the device for producing static electricity on the network from which said device for producing static electricity is capable of being disconnected from the network; and

 configure the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection are less than the time / current curve.

The invention also relates to a method of installing a starting protection configuration device according to the preceding characteristic, on a network capable of being isolated from a main network, said starting protection being adapted to put the network portion, downstream of said protection, de-energized as a function of the current value passing through it. DESCRIPTION OF THE FIGURES Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which will follow, with reference to the appended figures, given by way of nonlimiting examples and in which:

 - Figure 1 illustrates the topology of a network, capable of being isolated from a main network, implementing a protection method according to the invention;

 - Figure 2 illustrates a starting protection setting curve according to the state of the art; FIG. 3 illustrates a reverse time tripping curve of a charge according to the state of the art;

 Figure 4 illustrates a template of overload according to the state of the art;

 - Figure 5 schematically shows the main steps of a protection method according to the invention;

 FIG. 6A illustrates the results of short-circuit simulations carried out with a temporal simulation model of the network and of a device for producing static electricity according to the invention;

 FIG. 6B illustrates a time / current curve, developed according to the method of the invention, representing the current passing through a starting protection on the network and characteristic of the overload of the device for producing static electricity, that is to say say from which the static electricity production device is likely to disconnect from the main network; and

 FIG. 7 illustrates the setting of a starting protection according to the time / current curve, according to the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

 With reference to FIG. 1, a portion of the power supply network 100 is illustrated. The topology of said network 100 can be described according to a set of sections, each section having a length, a type of conductor and two end nodes. (such as customer connection nodes for example).

 The network 100 comprises a supply zone comprising a supply network or synchronous group 101, and at least one device for producing static electricity 102.

The network 100 also includes a zero sequence voltage relay 103. This detects if a zero sequence voltage appears on the network, which means that there is a fault at the earth upstream of a voltage transformer 104 (described by its short-circuit voltage, its power and its coupling). In this case, it can open a switch 107 of the static electricity production device 102.

 The network 100 can also include “feeder protections” (for example a circuit breaker and a protection relay) 105. These monitor the value of the current flowing through them and can be triggered to de-energize the downstream network. They have for this as illustrated in Figure 2:

 a magnetic threshold SM adjustable in time and intensity;

 of a thermal trip curve ST composed of several segments of length adjustment, and adjustments in time, intensity and time / intensity director coefficient.

Referring again to FIG. 1, a plurality of loads / consumer customers 106 have, among other things, a so-called “branch circuit breaker” protection (not shown) capable of tripping and therefore disconnecting them from the network 100 in the event of a phase fault. -phase or phase-neutral with them.

 The opening time of this connection circuit breaker is defined by a curve called "customer reverse time trip curve" (CD), as illustrated in Figure 3.

 This protection thus includes a time-dependent triggering threshold, the delay decreasing when the measured current increases. Indeed, in the event of a strong current, it is important that the protection is activated quickly to avoid damage to the equipment. On the other hand, when the current is relatively low compared to what the equipment can withstand, the time delay must be long in order to avoid inadvertent tripping.

With reference to FIG. 4, the static electricity production device 102 has an OCC overload template (known as “Overload Current Capacity”) which determines, for several current values greater than its nominal current In (which can be delivered without time limit), the duration during which the static electricity production device 102 can deliver this current, without disconnecting and from a maximum current Imax.

The OCC template is described by a set of end segments (Ik, tn), k being for example between 1 and 4, I being the axis representing the percentage of current delivered in relation to the nominal current, and t l axis representing the duration during which this current can be injected. Thus, as illustrated, the overload template determines the duration during which the static electricity production device 102 can deliver a current greater than its nominal current, for example 120% for 10s (I2, t2), 150% for 2s ( I3, t3) and 200% for 200 ms (I4, t4) without disconnecting, depending on the current delivered. The maximum current Imax being determined by the maximum current with reference to the OCC overload template.

With reference to FIG. 5, there are now illustrated certain steps of a process for developing a network protection plan when the latter has a “microgrid” type supply of electricity, that is to say that 'it can be disconnected from a main network and the power supply can be achieved by sources which are not synchronous rotating generators, that is to say static generators.

 The method can be implemented by a device 200 for configuring initial protection, said device 200 comprises processing means, typically a processor, as well as a memory. The device 200 can be integrated into a starting protection 105 or separate from it.

In a step E10, it is determined, for example by a sensor, if at least one power group at least equal to the power of the smallest synchronous group capable of supplying the network alone is energized, or if the network of power supply is connected.

 In this case, in a step E20, the protection plan is determined according to the settings proposed by the operator of the network 100.

 Otherwise, in the case where only the static electricity production device 102 is connected, in a step E30, an isolated supply configuration mode is activated. The protection plan is thus determined according to the settings determined by the process.

 For this purpose, the method may have at least one telecommunication means enabling it to change the settings of the protection of the departures.

Following step E30, it is determined in a step E31 if the static electricity production device 102 has a neutral ground. In fact, when the static electricity production device 102 supplies the network alone, if the latter has no earthing, the network upstream of the transformer is in isolated neutral. The zero sequence voltage relay must then be active. Thus, in a step E32, the zero sequence voltage relay is activated. Also following step E30, in a step E33, parallel to or after step E31, the protection settings are calculated.

 This calculation can take into account the following parameters, described for example in a user interface:

 - customer trigger curves (CD);

 the minimum short-circuit power of the supply network;

 - the power of the smallest synchronous group capable of supplying the network alone and of its synchronous, subtransient and transient reactances;

 - the settings of the "feeder protections" valid in the most unfavorable case among the cases "supply of the network by the supply network" or "supply by the smallest synchronous group capable of supplying the network alone";

 an Imax value associated with each portion of the network downstream of the feeder protections. This is the maximum current that can be called by this departure; and

 - a maximum time for eliminating the network fault: T_defaut_max

In a sub-step E33a of E33, it is produced from the values of Imax and In, a temporal simulation model of the device for producing static electricity 102.

 Also, from the network topology, a simulation model comprising the network 100 and the static electricity production device 102 is created. Thus, with this model, simulations of single-phase, two-phase and three-phase short circuits are carried out at each node of the network downstream of a starting protection 105;

 Then, the process records:

 - the largest currents, among the currents of each phase, delivered by the static electricity production device 102 (static generator current) and

 - the greatest current i among the currents of each phase which circulates in the start protection upstream of the node on which the short-circuit was made (start protection current).

 This set of points (static generator current; starting protection current) obtained in this step, is for example illustrated in the curve in FIG. 6A.

Subsequently, with reference to FIG. 6B, in a substep E33b of E33, with the function i = f (u) described by means of the OCC template of the device for producing static electricity 102, and using the current delivered by the static electricity production device 102 as a joining element, all the coordinate points are calculated [Current departure protection i; Time t]. A so-called “SURCH-TC” curve is thus obtained, representing the limit from which the static electricity production device 102 will disconnect, but using only quantities measured by the protections of the feeders (the time and the current flowing through them).

Referring now to FIG. 7, in a sub-step step E33c of E33, the protections of the feeders are processed one by one. Thus all the results of the nodes downstream of the same start protection are isolated. Then, these points are transferred to a time / current diagram. A curve known as "SURCH-TC-DEPART" is thus obtained representing the duration during which the static electricity production device 102 can deliver a current greater than its nominal current, and therefore the characteristic in overload of the device for producing static electricity 102 on the network 100 from which said device 102 is capable of disconnecting from the network 100

In addition, the smallest short-circuit current, called Iccmin, is determined for each set of nodes downstream of a starting protection. This value Iccmin is then plotted on the time / current diagram in FIG. 7.

 The time / current diagram also includes the reporting of the Imax value determined by the public network operator, the reporting of customer trigger curves, and the placement of a coordinate point [Icc min, T_defaut_max]

In a step E34, a setting is then determined for the protection of the feeder, for example according to one or more configuration rules.

 For example, in a particular embodiment, step E34 is carried out according to at least one of the following rules:

 - the start protection curve is under the "SURCH-TC-DEPART" curve with a maximum safety margin based on the uncertainties relating to the cut-off time of the cut-off devices and simulation models. Typically a value greater than about 100 ms;

 - the departure protection curve is above all customer trigger curves with a determined maximum safety margin. For example, a margin greater than about 100 ms;

the start protection curve is to the right of the Imax curve, with a determined maximum safety margin. For example a margin greater than around 10% of Imax; the start protection curve is to the left of the point [Icc min, T_defaut_max] with a determined maximum safety margin. For example, a margin greater than about 20% of Icc min.

Thus, thanks to the protection process:

 a phase / phase or phase / neutral fault at a customer will de-energize the customer before the start 105 protections are triggered

 a phase / phase or phase / neutral fault on the network will turn off the faulty part of the network, and the static electricity production device 102 will not disconnect.

In a particular embodiment, optional parameters are also proposed for determining the setting of the starting protections.

 Thus, an active or non-active “total selectivity mandatory” parameter can be proposed (by default active).

 If this parameter is active and if for at least one starting protection, step E34 does not succeed in determining a setting which satisfies the rules previously exposed, then the device for producing static electricity 102 is disconnected. .

 For this purpose, the method has a means of forcing the shutdown of the device for producing static electricity 102.

 If the setting is non-active, and if for at least one start protection 105 step E34 does not succeed in determining a setting which satisfies the rules previously exposed, then a setting is determined according to a predetermined rule.

 For example, a rule according to which "the start protection curve is to the left of the point [min Isc, 500 ms] with a maximum safety margin greater than 20% of Isc min" and which satisfies the maximum number of rules among the 3 remaining rules described previously. Thus, in this example, a fault with a client either will trigger the protection of the client, or it will cause the triggering of the start protection in 500 ms. Selectivity is not guaranteed but security is well guaranteed.

 If no adjustment is possible, the static electricity production device 102 is then disconnected.

In a particular embodiment, an expert mode is also proposed. In this expert mode, the network operator can enter for each node a minimum short-circuit current value (lcc_min_cli_Gr_Res) calculated with the methods known to those skilled in the art and corresponding to the type of supply "synchronous group or power network ”.

 Then in this mode, the maximum tripping times of the customer connection circuit breakers are calculated:

 with the value lcc_min_cli_Gr_Res, for the case "synchronous group or a power supply network".

 for the electrical micro-grid case using the values of i calculated previously.

If for a customer or more the triggering time is greater than a configurable value, typically around 20 ms for 50Hz networks, either for the case of “synchronous group or a supply network” or for the electric micro-network case, in an optional step the process determines / indicates whether the client is part of case 1, 2 or 3 defined by:

 Case 1: tripping time is more than 20 ms in the “synchronous group or power supply” and electrical micro-network cases.

 Case 2: tripping time is more than 20 ms in electrical micro-grid cases only

 Case 3: tripping time is more than 20 ms in the "synchronous group or power supply" cases only.

To resolve these problematic cases, the process determines and indicates for example to the operator that:

 In case 2: the operator must modify the static electricity production device 102 or reinforce the network.

 In case 3: the operator must modify the synchronous group or modify the supply network or reinforce the network "

In case 1, the method performs an additional calculation sub-step in step E34. In this substep, the static electricity production device 102 is replaced by an ideal voltage source and the new short-circuit currents are calculated.

In a first case 1 .1: the values with ideal voltage source are approximately 10% equal to the case of “electrical micro-network” or to the case of “synchronous group or network or both. The method then determines and indicates for example to the operator that it must proceed with the reinforcement of the network.

 In this case, the customer is very far electrically from the transformer. In these cases where it is very far away, if the impedance of the fault loop forms a power load lower than the nominal power of the device for producing static electricity 102, then the device 102 is able to supply a fault. without exceeding its nominal current. It is also able to keep the value of the voltage across its terminals close to 1. So in this case 1.1 the type of power supply does not considerably modify the short-circuit current and even a voltage source with infinite power cannot increase the value of the short-circuit current.

 In a second case 1.2: the values with ideal voltage source are more than around 10% higher than in the case of "electrical micro-grid" and in the case of "synchronous group or a power supply network". The method then determines and indicates, for example, to the operator that it must modify the synchronous group or supply network, and modify the device for producing static electricity 102.

Claims

1. Method for protecting a network (100) capable of being isolated from a main network, said network (100) comprising:  a device for producing static electricity (102) supplying the network (100); - At least one starting protection (105) adapted to put the network portion, downstream of said protection, de-energized as a function of the current value passing through it; at least one charge for consuming electricity (106) downstream of the starting protection (105);  at least one means of adjusting the starting protection (105) adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection (105); the static electricity production device (102), when it supplies the network (100) in an isolated configuration, having an overload gauge (OCC) specifying the duration during which the static electricity production device (102 ) can deliver a current greater than its nominal current without disconnecting, depending on the current delivered, said method being characterized in that it comprises the steps of:  determination of a simulation model (MS) describing the behavior of the device for producing static electricity (105) on a defined network;  - simulations of single-phase, two-phase and three-phase short-circuits at each network node (100) downstream of the protection (105) to determine a set of points Generating current / Start protection current, corresponding respectively to:  o greatest currents, among the currents of each phase, delivered by the static electricity production device (102) and  o greatest current among the currents of each phase passing through the flow protection (105) upstream of the node on which the short-circuit was made; and from the values of Static generator current and according to the overload gauge (OCC); determination of a time / current curve (SURCH-TC-DEPART) crossing the protection (105), which represents the overload characteristic of the device for producing static electricity (102) on the network (100) from which said device (102) is likely to disconnect from the network (100); and configuration of the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection (105) are less than the time / current curve (SURCH-TC-DEPART). 2. Method for protecting a network (100) according to the preceding claim, in which the magnetic and / or thermal trigger threshold characteristics of the starting protection are lower, by at least a predefined time margin, than the curve. time / current (SURCH-TC-DEPART) of the static electricity production device (102). 3. A method of protecting a network (100) according to one of the preceding claims in which the load (106) also comprises a connection circuit breaker capable of opening to disconnect said load (106) from the network (100), said circuit breaker being characterized by a tripping curve (CD) which determines its opening time as a function of the current value which crosses; and in which the magnetic and / or thermal trigger threshold characteristics of the starting protection (105) are greater, by at least a predefined time margin, than the trigger curve (CD). 4. Method for protecting a network (100) according to claim 2 or 3, in which the predefined time margin is approximately 100 ms. 5. Method for protecting a network (100) according to one of the preceding claims, in which the method also includes a predefined Imax value associated with each portion of the network downstream from the starting protection (105), said corresponding Imax value. at the maximum current which can be called by said departure (105); and in which the magnetic and / or thermal trip threshold characteristics of the initial protection are greater, by at least a 10% intensity margin of Imax, than Imax. 6. Method for protecting a network (100) according to one of the preceding claims, in which the method also comprises: determining a minimum short-circuit current value Iccmin for each set of load connection nodes (106) downstream of an outgoing protection (105);  obtaining a maximum time for eliminating a predefined network fault Tmax; and in which  the thermal trip threshold characteristics of the starting protection are lower in time or intensity than Tmax or Iccmin; 7. System for protecting a network (100) capable of being isolated from a main network, said network (100) comprising:  a device for producing static electricity (102) supplying the network (100); - At least one starting protection (105) adapted to put the network portion, downstream of said protection, de-energized as a function of the current value passing through it; at least one charge for consuming electricity (106) downstream of the starting protection (105);  at least one means of adjusting the starting protection (105) adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection (105); the static electricity production device (102), when it supplies the network (100) in an isolated configuration, having an overload gauge (OCC) specifying the duration during which the static electricity production device (102 ) can deliver a current greater than its nominal current without disconnecting, depending on the current delivered, said system (100) being characterized in that it comprises at least:  means for determining a simulation model (MS) describing the behavior of the device for producing static electricity (105) on a defined network;  a means of simulating single-phase, two-phase and three-phase short-circuits at each node of the network (100) downstream of the protection (105) to determine a set of points Generating current / Start protection current, corresponding respectively to:  o greatest currents, among the currents of each phase, delivered by the device for producing static electricity (102) and o greatest current among the currents of each phase passing through the flow protection (105) upstream of the node on which the short-circuit was made; a means of determining, from the values of static generator current and as a function of the overload gauge (OCC), of a curve (SURCH-TC-DEPART) time / current passing through the protection (105), which represents the characteristic in overload of the static electricity production device (102) from which said device (102) is capable of disconnecting from the network (100); and  a means for configuring the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection (105) are less than the time / current curve (SURCH-TC-DEPART). 8. Network (100) capable of being isolated from a main network, said network (100) comprising:  a device for producing static electricity (102) supplying the network (100); - At least one starting protection (105) adapted to put the network portion, downstream of said protection, de-energized as a function of the current value passing through it; at least one charge for consuming electricity (106) downstream of the starting protection (105);  at least one means of adjusting the starting protection (105) adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection (105); the static electricity production device (102), when it supplies the network (100) in an isolated configuration, having an overload gauge (OCC) specifying the duration during which the static electricity production device (102 ) can deliver a current greater than its nominal current without disconnecting, depending on the current delivered, said network (100) being characterized in that it comprises at least:  means for determining a simulation model (MS) describing the behavior of the device for producing static electricity (105) on a defined network;  a means of simulating single-phase, two-phase and three-phase short-circuits at each node of the network (100) downstream of the protection (105) to determine a set of points Generating current / Start protection current, corresponding respectively to: o greatest currents, among the currents of each phase, delivered by the device for producing static electricity (102) and o greatest current among the currents of each phase passing through the flow protection (105) upstream of the node on which the short-circuit was made;  a means of determining, from the values of static generator current and as a function of the overload gauge (OCC), of a curve (SURCH-TC-DEPART) time / current passing through the protection (105), which represents the characteristic in overload of the static electricity production device (102) on the network (100) from which said device (102) is capable of disconnecting from the network (100); and a means for configuring the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection (105) are less than the time / current curve (SURCH-TC-DEPART). 9. Device (200) for configuring the starting protection (105) of a network (100) capable of being isolated from a main network, said starting protection (105) being adapted to bring the network portion into downstream of said protection, de-energized as a function of the current value passing through it, said network (100) comprising:  a device for producing static electricity (102) supplying the network (100); at least one charge for consuming electricity (106) downstream of the starting protection (105);  - At least one means of adjusting the starting protection (105) adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection (105); the static electricity production device (102), when it supplies the network (100) in an isolated configuration, having an overload gauge (OCC) specifying the duration during which the static electricity production device (102 ) can deliver a current greater than its nominal current without disconnecting, depending on the current delivered, the device (200) for configuring the starting protection being configured to:  determining a simulation model (MS) describing the behavior of the device for producing static electricity (105) on a defined network;  - simulate single-phase, two-phase and three-phase short-circuits at each network node (100) downstream of the protection (105) to determine a set of points Static generator current / Starting protection current, corresponding respectively to: o greatest currents, among the currents of each phase, delivered by the device for producing static electricity (102) and  o greatest current among the currents of each phase passing through the flow protection (105) upstream of the node on which the short-circuit was made; and from the values of Static generator current and according to the overload gauge (OCC);  determining a curve (SURCH-TC-DEPART) time / current passing through the protection (105), which represents the characteristic in overload of the device for producing static electricity (102) on the network (100) from which said device ( 102) is likely to disconnect from the network (100); and  configure the adjustment means such that the magnetic and / or thermal trip threshold characteristics of the starting protection (105) are less than the time / current curve (SURCH-TC-DEPART). 10. A method of installing a device (200) for configuring outgoing protection (105) according to the preceding claim, on a network (100) capable of being isolated from a main network, said outgoing protection (105 ) being adapted to switch off the network portion, downstream of said protection, as a function of the current value passing through it, said network (100) comprising:  a device for producing static electricity (102) supplying the network (100); at least one charge for consuming electricity (106) downstream of the starting protection (105);  at least one means of adjusting the starting protection (105) adapted to adjust in time and intensity, a magnetic and / or thermal tripping threshold of said starting protection (105);  the static electricity production device (102), when it supplies the network (100) in an isolated configuration, having an overload gauge (OCC) specifying the duration during which the static electricity production device (102 ) can deliver a current greater than its nominal current without disconnecting, depending on the current delivered.