WO2007060328A1

WO2007060328A1 - Control method and device for a decentralised energy production device and installation comprising at least two production devices which are provided with said control device

Info

Publication number: WO2007060328A1
Application number: PCT/FR2006/002571
Authority: WO
Inventors: Quoc Tuan Tran; Guillaume Rami; Antonio Almeida; Nouredine Hadjsaid; Jean-Christophe Kieny; Jean-Claude Sabonnadiere
Original assignee: Schneider Electric Industries Sas
Priority date: 2005-11-25
Filing date: 2006-11-23
Publication date: 2007-05-31
Also published as: FR2894087A1; FR2894087B1

Abstract

The invention relates to a control method and device for a decentralised energy production device and to an installation comprising at least two production devices which are provided with said control device. The inventive control method comprises the following steps consisting in: measuring the voltage (Vmes) and current (Imes); controlling the power exchanged when the measured voltage (Vmes) is within a target range (Vminl - Vmaxl), said target range falling within a tolerance range (Vmin2 - Vmax2) of the network; and controlling the voltage at the connection point of the decentralised energy production device, consisting in acting on the decentralised energy production device such as to (i) absorb or produce the reactive power (Q) when the measured voltage (Vmes) is within the target range and (ii) reduce or increase the active power (P) produced when the produced or absorbed reactive power has reached a limit when the measured voltage (Vmes) is outside of a tolerance range. The inventive control device can be used to carry out the above method.

Description

METHOD AND DEVICE FOR CONTROLLING A DECENTRALIZED PRODUCTION DEVICE OF ENERGY, AND INSTALLATION COMPRISING AT LEAST TWO PRODUCTION DEVICES HAVING THE SAID REGULATION DEVICE

TECHNICAL FIELD OF THE INVENTION

The invention relates to a control method for a decentralized energy production device connected to a distribution network comprising:

a measurement of voltage and current at a point of connection to the network of the decentralized energy production device,

a power regulation exchanged by the decentralized energy production device, when the measured voltage is within a target range between a minimum target limit and a maximum target limit, said target range being within an admissibility range of the network voltage, and

a regulation of the voltage at the connection point of the decentralized energy production device in which the decentralized energy production device is operated so as to:

1) absorbing reactive power when the measured voltage is greater than the maximum target limit,

2) produce reactive power when the measured voltage is below the minimum target limit,

3) reducing the active power produced when the reactive power absorbed by the distributed power generation device has reached an absorbed reactive power limit, and

4) to increase the active power produced when the reactive power produced by the decentralized energy production device has reached a reactive power limit produced. The invention also relates to a control device for a decentralized energy production device connected to a distribution network comprising:

means for measuring voltage and current at a point of connection to the network of the decentralized energy production device,

power regulation means exchanged by the decentralized energy production device, said power regulation means being implemented when the measured voltage lies within a target range between a minimum target limit and a maximum target limit, said target range being within a range of eligibility of the network voltage, and

means for regulating the voltage at the connection point of the decentralized energy production device, said voltage regulation means being implemented when the measured voltage is outside the target range, by acting on the device of decentralized production of energy so as to absorb or produce reactive power, and / or to reduce or increase the active power produced.

The invention also relates to an installation comprising an electricity distribution network and at least two decentralized energy production devices connected at different connection points of said network.

STATE OF THE ART [0004] The connection of a decentralized energy production device, abbreviated to PDE, on a distribution network tends to modify the voltage plan on the network. Indeed, not only do these types of devices produce active power, but some can produce or absorb reactive power. The installation of a decentralized energy production device has the effect of raising the level of voltage on the distribution network. Load variations and the intermittent nature of some decentralized power generation devices can cause significant voltage variations and can trigger the protection of certain distributed power generation devices or their disconnection from the distribution network. To overcome these voltage variations, it is known to use optimal power distribution algorithms between different decentralized energy production devices of the same network, through a network manager. However, the implementation of means of communication between these decentralized energy production devices and the manager is often complex and expensive.

[0006] It is also known from French patent FR 2,823,381, a method of regulating a decentralized electrical energy production device comprising a power regulation when the voltage is within the limits of a target range. and voltage regulation when the voltage is outside these limits. In reactive power control, the reactive power is kept constant at a default value, or by the power factor. During voltage regulation, the device absorbs or produces reactive power to bring the voltage back within the determined range. When the reactive power absorbed or produced by the device has reached limit values and it is no longer possible to maintain the voltage within the target range, the active power of the device is then varied to reduce the voltage in the device. the limits of this beach.

The variations of the reactive power absorbed or produced by a decentralized energy production device equipped with this type of regulation of the prior art are likely to cause significant voltage variations at other points in the distribution network. . The presence of several decentralized energy production devices equipped with this type of regulation, on the same distribution network, tends to increase these voltage variations tenfold and to increase the risk of having points of the network having a voltage outside them. the range of eligibility of the network voltage.

Furthermore, the implementation of the regulation method of the prior art often requires a parameterization, in particular a determination of the limits of the target voltage range, taking into account the overall voltage plane of the network of distribution. Thus, the control method of the prior art does not completely overcome a centralized control strategy, manual or automatic, in which the overall voltage plane of the distribution network and the position of the control device. decentralized generation of energy to which the regulation is applied in said network must be taken into account for the parameterization.

SUMMARY OF THE INVENTION

The invention aims to overcome the disadvantages of the state of the art by proposing a control method for a decentralized power generation device connected to the distribution network responding in particular to the conditions relating to the maintenance of the network voltage. in an eligibility range.

The invention therefore relates to a control method for a decentralized energy production device connected to a distribution network comprising:

3) reducing the active power produced when the reactive power absorbed by the distributed power generation device has reached an absorbed reactive power limit, and 4) to increase the active power produced when the reactive power produced by the decentralized energy production device has reached a reactive power limit produced.

In the regulation method of the invention, the regulation of the voltage by reduction of the active power produced is carried out when the measured voltage is greater than a maximum admissibility limit, and the regulation of the voltage by increasing the the active power produced is realized when the measured voltage is lower than a minimum eligibility limit.

In a first embodiment of the invention, the minimum and maximum target limits are fixed.

In a particular case, the regulation of the voltage comprises a voltage regulation loop by absorption or reactive power production comprising the determination of a voltage difference between the measured voltage and a voltage setpoint and the variation of the voltage. reactive power absorbed or produced by a fuzzy logic process, the input variables of said process being said voltage deviation and the function derived from said deviation from time.

The regulation of the voltage may comprise a reactive power absorption voltage regulation loop comprising the determination of a difference between the measured voltage and the maximum target limit, and the variation of the reactive power produced by a proportional correction. integral of said deviation with a saturation of the reactive power between the reactive power absorbed limit and zero. The voltage regulation may also include a voltage regulation loop by reactive power generation comprising determining a difference between the measured voltage and the minimum target limit, and the variation of the reactive power absorbed by a proportional integral correction of said voltage. deviation with a saturation of the reactive power between zero and the reactive power limit produced. Advantageously, the regulation method comprises the determination of parameters of the integral proportional correction by a fuzzy logic process, the input variables of said process being the difference between the measured voltage and the maximum target limit and / or the difference between the measured voltage and the minimum target limit, and the derivative of said deviations from time. In a second preferred embodiment, the regulation method comprises determining, automatically and adaptively, the values of the minimum and maximum target limits of said target range, as a function of the measured voltage and / or the power. reactive absorbed or produced, the value of the maximum target limit being kept less than or equal to the maximum eligibility limit and the value of the minimum target limit being maintained greater than or equal to the minimum eligibility limit.

Preferably, the regulation method, according to this second embodiment, comprises:

increasing or maintaining at a substantially constant value the value of the maximum target limit, when the measured voltage increases and / or when the reactive power absorbed increases,

decreasing or maintaining the value of the maximum target limit at a substantially constant value, when the measured voltage decreases and / or when the reactive power absorbed decreases,

decreasing or maintaining at a substantially constant value the value of the minimum target limit, when the measured voltage decreases and / or when the reactive power produced increases, or

increasing or maintaining at a substantially constant value the value of the minimum target limit, when the measured voltage increases and / or when the reactive power produced decreases.

[0017] Advantageously, the maximum or minimum target limit is increased or decreased in one or more steps.

Advantageously, the regulation method comprises maintaining the values of the target limits at substantially constant values, when the measured voltage and the reactive power are distributed in a zone, a voltage and reactive power plane, s'. extending along an axis passing through a first point corresponding to the minimum eligibility limit and the reactive power absorbed limit, and a second point corresponding to the maximum eligibility limit and the reactive power limit produced.

[0019] Preferably, the values of the minimum and / or maximum target limits are determined by fuzzy logic processing.

Preferably, the values of the minimum and maximum target limits are determined by calculating the differences between said target limits and a nominal value of the voltage by the following steps:

the determination of a coefficient by a fuzzy logic process from the measured voltage and the reactive power absorbed or produced,

- the determination of the differences between the minimum and maximum eligibility limits, and a nominal value of the voltage, and

- the determination of the deviations between the minimum and maximum target limits, and the nominal value of the voltage, by multiplying the deviations between the minimum and maximum eligibility limits, and the nominal value of the voltage by the coefficient determined by the fuzzy logic process.

The invention also relates to a control device for a decentralized energy production device connected to a distribution network comprising:

means for regulating the voltage at the connection point of the decentralized energy production device, said voltage regulation means being implemented when the measured voltage is outside the target range, by acting on the decentralized energy production device for absorbing or producing reactive power, and / or for reducing or increasing the active power produced,

in which the regulation of the voltage by reduction of the active power produced is carried out when the measured voltage is greater than a maximum admissibility limit, and in which the regulation of the voltage by increasing the active power produced is carried out when the voltage measured is less than a minimum eligibility limit.

Preferably, the control device comprises a processing unit dedicated to determining the values of the minimum and maximum target limits of said target range, as a function of the measured voltage and / or the reactive power. Advantageously, the set of processing dedicated to the determination of the values of the minimum and maximum target limits is a fuzzy logic processing module.

[0023] Preferably, the fuzzy logic processing module comprises:

a module for determining normalized values of the measured voltage and the reactive power absorbed or produced,

a module for determining a coefficient from said normalized values,

a module for determining the differences between the minimum and maximum eligibility limits, and a nominal value of the voltage, and

- a module for determining the differences between the minimum and maximum target limits, and the nominal value of the voltage, by multiplying the differences between the minimum and maximum permissible limits of eligibility and the nominal value of the voltage by the determined coefficient by the fuzzy logic process.

The invention also relates to an installation comprising an electricity distribution network and at least two decentralized energy production devices connected at different connection points of said network, characterized in that each of said at least two production devices decentralized energy is provided with a regulation device described above and implementing: means for measuring voltage and current at a point of connection to the network of the decentralized energy production device,

power regulation means exchanged by the decentralized energy production device, and

means for regulating the voltage at the connection point of the decentralized energy production device.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages and features will emerge more clearly from the following description of a particular embodiment of the invention, given by way of non-limiting example, and shown in the accompanying drawings, in which:

Figure 1 shows schematically the connection to the distribution network of an electrical installation comprising a decentralized energy production device;

- Figure 2 schematically shows the connection to the distribution network of a decentralized energy production device with a regulation according to the prior art;

FIG. 3 is a flowchart showing the regulation method according to the prior art;

FIG. 4 schematically represents the connection to the distribution network of a decentralized energy production device provided with a regulation according to a first embodiment of the invention, in which the voltage target range is fixed;

- Figure 5 shows schematically the different operating speeds, depending on the measured voltage and the reactive power exchanged;

FIG. 6 is a flow diagram of the control method according to the first embodiment of the invention;

FIG. 7 diagrammatically represents, in a particular case of the first embodiment, a regulation of the voltage by absorption or reactive power generation; Figure 8 shows an improvement adaptable to each of the voltage regulation loops shown in Figure 6;

FIG. 9 schematically represents the connection to the distribution network of a decentralized energy production device provided with a self-adaptive regulation, according to a second embodiment of the invention, in which the target voltage range is variable;

FIG. 10 represents, in more detail, the regulation processing module of FIG. 9;

FIG. 11 represents, by a flowchart, the self-adaptive regulation method according to the second embodiment of the invention;

FIG. 12 illustrates, by a three-dimensional graph, the variation of a coefficient K by a fuzzy logic processing module, from which the voltage target limits are determined as a function of the input variables constituted by the measured voltage. and the reactive power exchanged;

FIG. 13 represents a distribution network on which simulations of different regulation methods have been carried out;

FIG. 14 represents a table of results of the simulations comprising the values of the measured voltage, at a given time, at different connection points of the decentralized energy production devices to the network;

FIG. 15 represents, for each simulation, the variations of the voltage as a function of time, at a connection point of a given decentralized energy production device;

FIG. 16 represents, for each simulation, the variations of the reactive power exchanged as a function of time, at the same connection point as in FIG. 13;

FIG. 17 represents the variations of the minimum and maximum target limits for the simulation of the second embodiment in which the limits of the target range are determined iteratively. DETAILED DESCRIPTION

In a conventional distribution network with a single supply station producing electrical energy, the voltage is higher at the power station and decreases to the end of the network. In this case, the power flows in one direction, from the power station to consumers. But with the presence of decentralized energy production devices connected to the network, power flows in both directions and the voltage plan is changed.

The installation of a decentralized energy production device on an electrical distribution network is generally subject to constraints. Often, the installation of the decentralized energy production device must be compatible with the maintenance of the voltage, at any point of delivery of the network, within eligibility ranges. By way of example, the range of eligibility of the voltage can range from 230V-10% to 230V + 6% for the low-voltage network, and from -5% to + 5% of the contractual voltage, in general 20 kV, for the medium voltage network, also called HTA network in some normalizations.

FIG. 1 schematically represents the connection of an installation comprising a decentralized energy production device, abbreviated as PDE, to the energy distribution network 11 by means of an electrical line 12. The electric line is represented by a conductor 13, a reactance X and a resistor R. The installation comprises a load 14, a decentralized energy production device 15, and a reactive energy compensation device 16. The relative voltage variation between the network 11 and the connection point 17 of the decentralized energy production device is determined by:

AV _ R (P _G - P _L ) + X (± Q _G - Q _L ± Q _C ) VV ²

Or: V is the compound voltage R, X is the resistance and the total reactance of the line, PG, QG are the active and reactive powers provided by PDE,

PL, Q _L are the active and reactive powers of consumption, Qc is the reactive power of the compensation device. According to the structure of the network, the location of the connection point of the decentralized energy production device on this network and the power injected by the decentralized energy production device, the voltage can be high. at the point of connection and sometimes even exceed the eligibility limit. In the distribution network, the linear resistance may be greater than the linear reactance. Thus, the active power produced by the decentralized power generation device tends to change the overall voltage plan of the network.

Moreover, the production of most decentralized energy production devices is not guaranteed, especially for renewable energy sources whose intermittent nature can cause unexpected fluctuations in voltage. This leads to further modifications of the overall network voltage plan.

The voltage plan in the distribution network also depends on the consumption level and the load power factor, and any change in load causes a voltage variation on the network.

Thus, the variation of the voltage plan of an electrical distribution network can be caused in particular by:

the load and its variations,

the decentralized production of energy and its variations linked to its intermittent nature,

the compensation means and their adjustment,

- the configuration of the network.

[0034] Conventionally, there are two modes of regulation of a decentralized energy production device:

a voltage regulation mode, known in English as "Automatic Voltage Regulator", abbreviated to AVR, which makes it possible to maintain, within the limits of the system, the voltage at the connection point of the decentralized energy production device to the network substantially constant, and a reactive power regulation mode, also known as power factor regulation, also known in English under the terms "Power Factor / Reactive"

Power Regulator, abbreviated as PF / VAR, which makes it possible to keep the reactive power produced or absorbed by the decentralized energy production device substantially constant.

The voltage regulation mode is frequently used for large power generators, generally greater than a few tens of MVA, in particular for generators operating on the transport networks or for generators operating in a separate network. The reactive power regulation mode is, in turn, often used for the decentralized production of energy by generators connected to the power distribution network, whose power varies from a few kVA to a few MVA.

A mixed control method, that is to say alternately implementing reactive power regulation and voltage regulation, is known from the prior art and described in French patent FR 2,823,381.

[0037] Figure 2 schematically shows the connection to the distribution network 21 of a decentralized energy production device 22 having a control 24, according to the prior art. The decentralized power generation device is connected to a connection point 23. The controller 24 is connected to a local voltage measurement Vmes and a local measurement 26 of current Imes. The regulation 24 is also connected to the decentralized energy production device for sending active power P and reactive power Q instructions exchanged. The control 24 of FIG. 2 further comprises an input 27 of the exchanged reactive power limit values Qmin and Qmax, and an input 28 of the target voltage range limit values Vmin1 and Vmax1.

The decentralized energy production device exchange, ie produces or absorbs reactive power with the network. In the remainder of the description, it will be stated that, when the device absorbs reactive power, the reactive power Q exchanged is counted negatively. Thus the reactive power Q exchanged, in this case absorbed, increases, in absolute value, but decreases, in relative value, towards an absorbed reactive power limit Qmin. In the same way, it will be stated that when the device produces the reactive power, the reactive power Q exchanged is counted positively. Thus, the reactive power Q exchanged, in this case produced, increases in absolute value and in relative value, towards a reactive power limit produced Qmax.

In the control method of the prior art, the reactive power regulation is implemented when the voltage is within the limits of a target range, and the voltage regulation is implemented when the voltage is outside these limits.

As shown in FIG. 3, the control method of the prior art comprises a first step 31 for measuring the voltage Vmes and the current lmes at the connection point of the decentralized energy production device to the network. . The reactive power is then determined in a step 32. The measured voltage Vmes is then compared with the limits Vmin1 and Vmax1 of the target voltage range, by comparison steps 33 and 34.

As long as the measured voltage is within the target range, the reactive power control is implemented, in a step 35, to maintain the reactive power produced or absorbed substantially constant. By reactive power control Q exchanged means any regulation to maintain the reactive power or power factor substantially constant. In particular, the term reactive power regulation encompasses any regulation of the power factor.

When the voltage is outside the target range, the voltage regulation is implemented by varying the reactive power Q exchanged, ie produced or absorbed, in order to reduce the voltage within the limits of the target range. When the reactive power Q exchanged by the device has reached limit values Qmin or Qmax, and it is no longer possible to maintain the voltage within the limits of the target range Vmin1 and

Vmaxl, it then varies the active power P of the device to reduce the voltage within this range.

More precisely, when the voltage is outside the target range, the reactive power Q exchanged, ie absorbed or produced, is compared with the maximum limit values Qmax and minimum Qmin of reactive powers, when comparative steps 36 and 37. Then there are at least four possibilities listed below. 1) When the measured voltage Vmes is greater than the maximum target limit Vmaxl and the reactive power Q absorbed is greater than the reactive power absorbed limit Qmin, the decentralized energy production device absorbs reactive power Q when a step 38.

2) When the measured voltage Vmes is lower than the minimum target limit Vminl and the reactive power Q produced is less than the reactive power output limit Qmax, the distributed power generation device generates reactive power Q when a step 39.

3) When the measured voltage Vmes is greater than the maximum target limit Vmaxl and the reactive power absorbed has reached a reactive power absorbed limit

Qmin, the decentralized energy production device reduces its production of active power P, during a step 40.

4) When the measured voltage Vmes is lower than the minimum target limit Vmin1 and the reactive power produced has reached a reactive power output limit Qmax, the active power output P is increased during a step 41.

First Embodiment: Fixed Voltage Target Range

According to a first embodiment of the regulation of the invention, the limits Vminl and Vmaxl of the target voltage range are fixed.

An example of regulation according to this first embodiment of the invention is shown in FIG. 4. With respect to FIG. 2, the regulation means 24 comprise, in addition, an entry 45 of the minimum limit values Vmin2 and Vmax2 of a voltage eligibility range encompassing the target voltage range.

Compared to the prior art, the regulation of the voltage by reduction of the active power P produced is implemented when the measured voltage Vmes is greater than the maximum admissibility limit Vmax2, and the regulation of the voltage by increasing the active power P produced is implemented when the measured voltage Vmes is lower than the minimum admissibility limit Vmin2. Thus, as shown in Figure 6, the control method according to this first embodiment further comprises two comparison steps 61 and 62 to determine whether the measured voltage Vmes is outside or outside the limits. minimum Vmin2 and maximum Vmax2 of the voltage eligibility range.

In general, as shown in FIG. 5, the implementation of the regulation according to the invention makes it possible to distinguish the following three operating modes:

When the measured voltage is within the voltage target range defined by the Vmin1 and Vmaxl limits, around a nominal voltage, the regulation operates in a normal regime. In this mode of operation, the regulating device keeps the reactive power or the power factor substantially constant. These two control modes correspond to the PF / VAR control mode. The normal operating range is represented by the area 51 in FIG.

When the Vmes voltage measurement is outside the voltage target range, the regulation operates in a disrupted said regime. When the measured voltage is greater than the maximum target limit (Vmes> Vmaxl), the regulation according to the invention switches to voltage regulation mode with a voltage setpoint equal to the maximum target limit Vmaxl, and the decentralized production device The energy absorbs reactive energy to decrease the voltage at the connection point until the measured voltage reaches the set point. At this time, the regulation maintains the maximum target voltage, until the voltage decreases and returns between the target limits, which allows the regulation to return to power control mode and therefore in normal operating mode. When the measured voltage Vmes is lower than the minimum target limit Vmin1, the regulation according to the invention switches to voltage regulation mode, with a voltage setpoint equal to the minimum target limit Vminl and the decentralized energy production device produced. reactive energy to increase the voltage at the connection point, until the measured voltage reaches the setpoint. At this time, the regulation maintains the minimum target voltage, until the voltage increases and returns between the target limits, which allows the regulation to revert to reactive power regulation mode and therefore in normal operating mode. The operating range under disturbed conditions is represented by the zone 52 of FIG.

Preferably, the transition between the normal operating regime and the disturbed operating speed is achieved with a delay function, for example of the hysteresis type, which avoids oscillations.

A third operating regime, qualified as a critical speed, can be achieved when the regulation according to the invention is initially disturbed regime and that one of the following two conditions is met:

the measured voltage Vmes is greater than a maximum admissibility limit Vmax2 and the reactive power absorbed by the decentralized energy production device reaches a limit value Qmin, or

the measured voltage Vmes is lower than a minimum admissibility limit Vmin2 and the reactive power supplied by the decentralized energy production device reaches a limit value Qmax.

In critical conditions, the control remains in voltage regulation mode but, unlike the disturbed operating mode, the voltage is regulated by varying the active power. Thus, in the case where the measured voltage is greater than the maximum admissibility limit (Vmes> Vmax2), the active power supplied by the decentralized energy production device is decreased, which has the effect of reducing the voltage at the same time. connection point to a value substantially equal to the maximum admissibility limit Vmax2. In the same way, in the case where the measured voltage is lower than the minimum admissibility limit (Vmes <Vmin2), the active power supplied by the decentralized energy production device is increased, which has the effect of increasing the voltage to a value substantially equal to the minimum admissibility limit Vmin2. In both cases, the reactive power absorbed or produced is kept at the limit value Qmin or Qmax, and it is not necessary to vary the active power P and the reactive power Q. Let us note that these reactive power limit values Q exchanged between the decentralized power generation device and the network vary according to the active power produced by said device. The reactive power limit values change according to the relation Q = ΛIS ² -P ² . The operating range in critical mode is represented by the area 53 of FIG.

Thus, by acting on the active power or the reactive power, the regulation according to the invention, and in particular the voltage regulation mode of the regulation of the invention, ensures a smooth operation in a many situations.

As previously described, the regulation means of the invention comprise a voltage regulation and a reactive power regulation. The voltage regulation generally comprises a measurement of the Vmes voltage and an action on the reactive power, when the measured voltage is outside the voltage target range, or an action on the active power, when the measured voltage is outside the voltage range. the eligibility range. An exemplary embodiment of a portion of the voltage regulation, in this case the voltage regulation acting on the reactive power exchanged, is shown in FIG.

In the embodiment shown in Figure 7, two control loops 71 and 72 allow the determination of the reactive power produced or absorbed. In the regulation loop 71, the difference Emax between the measured voltage Vmes and the maximum target limit Vmax1 is determined using a comparator 73. This difference Emax is then processed in a corrector comprising a proportional type module - Integral 74, abbreviated type PI, and an amplifier 75, for determining a reactive power setpoint absorbed by the decentralized energy production device. In the same way, in the regulation loop 72, the difference Emin between the measured voltage Vmes and the minimum target limit Vmin1 is determined using a comparator 76. This difference Emin is then processed in a corrector comprising a proportional type module - integral

77 and an amplifier 78, for determining a reactive power setpoint produced by the decentralized energy production device. The proportional - integral modules

74 and 77 of the correctors are combined with saturations respectively between Qmin and zero and between zero and Qmax.

As illustrated in Figure 8, at least one of the correctors 81 may include a fuzzy logic supervisor 82 for determining the proportional coefficient Kp and the integrator coefficient Ki of said corrector. In the case shown, this determination is made from the difference Emin or Emax, and the rate of variation of this difference determined in a differentiator module 83.

Note that in a particular case, not in accordance with the invention, where the four limits of the target range and the admissibility range are identical (Vmax1 = Vmin1 = Vmax2 = Vmin2), the decentralized production device of FIG. Thus regulated energy operates to maintain a constant voltage. In the regulating device of the invention, it can be provided to select this type of operation by simple parameterization. This type of operation corresponds to an islanding mode, ie a mode in which the power generation device is not connected to the distribution network.

Note also that in another particular case, not in accordance with the invention, where the minimum limits and the maximum limits, of the target range and the range of eligibility, are respectively equal to a maximum value and a minimum value (Vmin1 = Vmin2 and Vmax1 = Vmax2), the decentralized energy production device thus regulated operates so as to locally maintain the voltage at the connection point and interacts weakly with the distribution network to maintain the voltage in adjacent nodes of the network. In the regulating device of the invention, it may also be provided to select this type of operation by simple parameterization.

Outside of these two particular cases and according to one aspect of the invention, at any connection point of a decentralized energy production device, the voltage target range is within the range of eligibility of the invention. the voltage, and acts on the active power P produced by the decentralized energy production device only when the measured voltage Vmes is outside the limits of admissibility Vmin2 and Vmax2. Thus, in the first embodiment of the invention for which the voltage target range is fixed, the maximum target limit Vmax1 is strictly less than the maximum admissibility limit Vmax2, and the minimum target limit Vmin1 is strictly greater than the maximum limit. minimum eligibility Vmin2

The target voltage limits can be defined by any suitable means. Typically, the minimum target limit Vmin1 is chosen close to the nominal voltage at connection point, and the maximum target limit Vmax1 is chosen greater than approximately 4 to 5% of the value of this minimum target limit. This particular way of choosing the values of the voltage target limits is generally adapted to any type of network. The decentralized energy production device thus regulated contributes to maintaining a mains voltage plan in order to reduce losses. The target voltage limits can also be defined by the distribution network manager, with different values depending on the load and the location of the distributed power generation devices in the network. In the latter case, communication means may be provided between the regulating means and the manager.

Simulation of the first embodiment of the invention

The regulation according to the first embodiment of the invention, wherein the voltage target range is fixed, has been compared with a regulation according to the prior art. This comparison was conducted by tests carried out, using simulation means, on a distribution network represented in FIG. 13. This network is representative of a real rural network comprising 14 nodes, referenced from N1 to N1. these nodes being separated by electric lines whose length is reported in meters. A plurality of distributed power generation devices are connected to nodes of the distribution network, each device being referenced by the letters GED followed by the reference of the node to which it is connected. The network shown in Figure 13 is equipped with a 20 kV / 400V power station, with a power output of 160 kVA. All the simulations were carried out on the same scenario designed to vary the voltage at different points of the network, by acting on the load and / or on the power provided by the different decentralized energy production devices.

In a first simulation, the decentralized energy production devices are equipped with mixed regulation means, ie associating a voltage regulation and a reactive power regulation, in accordance with the prior art previously described. Thus, in this first simulation, the actions on the reactive power or on the active power are performed when the voltage at the connection point of the decentralized energy production device is outside a single and unique target range of voltage. In this first simulation, the target voltage limits are defined, with respect to a rated voltage value noted lpu, a minimum target limit Vmin1 equal to 0.9 * lpu and a maximum limit Vmaxl equal to 1.06 * lpu.

The " ^1st simulation" column of the table of FIG. 14 shows, at a given time, the relative values, with respect to the nominal voltage, of the voltage at different nodes of the distribution network to which decentralized production of energy. The voltage measured on the nodes 5, 10 and 11 of the network is outside the previously defined target limits. It is thus observed that the mixed regulation according to the prior art does not allow the maintenance of the voltage at any point of the network in the target voltage range.

In a second simulation, the decentralized energy production devices are equipped with regulation means according to the first embodiment of the invention, ie operating in relation to two distinct voltage ranges. In this second simulation, the reactive power actions are performed when the voltage at the connection point of the distributed power generation device is outside a first target voltage range and the actions on the active power are performed when this same voltage is outside a second voltage eligibility range encompassing the first. In the case of this second simulation, the voltage eligibility limits Vmin2 and Vmax2 were chosen identical to those of the target voltage range of the first simulation. The minimum target limits Vmin1 and maximum Vmax1 were, for their part, chosen respectively equal to 0.95 * lpu and 1.03 * lpu.

[0066] The column "2 ^nd simulation" in the table of Figure 14 shows that the voltage on the set of points of the distribution network is confined _inside. s voltage eligibility limits. The implementation of the regulation according to this first embodiment of the invention thus makes it possible, with respect to the regulation according to the prior art, to limit the voltage variations at any point of connection of the distribution network. Thus, a synergistic effect between the different devices provided with the regulation means according to this first embodiment is obtained, which makes it possible to maintain the overall voltage plan of the network. FIG. 15 represents the variations of the voltage 151, 152, 153 as a function of time at the connection point corresponding to the most critical node 11 of the network. These variations are caused by the simulation scenario. In the first simulation, the voltage at node 11, represented by curve 151, is outside the limits of admissibility between 10 and 20 seconds (Vmes <Vmin2) and between 80 and 90 seconds (Vmes> Vmax2). In the second simulation, this voltage, represented by the curve 152, is brought back within the range of eligibility.

As shown in FIG. 16, it is observed that the voltage has been reduced within the voltage eligibility limits by varying the reactive power produced, between 1 and 20 seconds, or the reactive power absorbed, between 80 and 90 seconds, up to a maximum value Qmax or a minimum value Qmin of the reactive power respectively. These reactive power variations are represented in FIG. 16, as a function of time, by the curves 161 and 162 respectively corresponding to the first and second simulations. It is also observed that the saturation time of the reactive power exchanged at the maximum values Qmax or minimum Qmin is longer in the second simulation compared to the first simulation. Thus, the regulation according to the first embodiment of the invention acts on the active power for a longer period, which makes it possible to maintain the voltage plane of the network in the admissibility range. Note that this maintenance of the voltage plan is at the cost of a saturation of the reactive power exchanged longer, for the device connected to the node 11 of the network.

Second Embodiment: Variable Voltage Target Range

According to a second embodiment of the regulation of the invention, the target voltage limits Vmin1 and Vmax1 are variable and determined regularly automatically and adaptively, depending on the measured voltage Vmes and / or the reactive power. Q exchanged. In this second embodiment, the value of the minimum target limit Vmin1 is greater than or equal to the minimum admissibility limit Vmin2, and the value of the maximum target limit Vmax1 is less than or equal to the maximum admissibility limit Vmax2. The target voltage limits Vmin1 and Vmaxl are determined taking into account the capacity of the decentralized energy production device to produce or absorb reactive power. This makes it possible to avoid the saturation of the reactive power exchanged by the decentralized energy production devices to be saturated too quickly, by distributing the capacity for adjusting the voltage intelligently between the different decentralized energy production devices. Moreover, thanks to this adaptive determination of the setpoints that constitute the target voltage limits Vmin1 and Vmax1, it is possible to make optimal use of the contribution of each decentralized energy production device endowed with such a regulation. adjustment of other devices with the same regulation and connected to the same distribution network.

The determination of the values of the target limits is generally performed, iteratively, in accordance with a certain number of rules. For example, these rules can be enacted as follows:

the value of the maximum target limit Vmax1 is increased or kept constant when the measured voltage Vmes increases and / or when the reactive power Q absorbed increases,

the value of the maximum target limit Vmax1 is decreased or kept constant when the measured voltage Vmes decreases and / or when the reactive power Q absorbed decreases,

the value of the minimum target limit Vmin1 is decreased or kept constant when the measured voltage Vmes decreases and / or when the reactive power Q produced increases, or

the value of the minimum target limit Vmin1 is increased or kept constant when the measured voltage Vmes increases and / or when the reactive power Q produced decreases.

The determination or the calculation of the target limits can be carried out so that the variations of these limits are made in one or more steps. There may also be areas in which the values of the target limits do not vary, for example when the measured voltage Vmes and the reactive power Q are distributed in an area, of a voltage and reactive power plane, extending along an axis passing through a first point corresponding to the minimum admissibility limit Vmin2 and the absorbed reactive power limit Qmin, and a second point corresponding to the maximum eligibility limit Vmax2 and the reactive power limit Qmax.

As shown in FIG. 9, the values of the minimum target limits Vmin1 and maximum Vmax1 are determined by means of fuzzy logic processing. With respect to FIG. 4, the regulation means 91 no longer have an entry of the minimum limit values Vmin1 and maximum value Vmax1 of the target voltage range. Note that these target limits could be entered manually, for example to perform an initialization. The control means 92 are approximately similar to the regulation means 24 shown in FIG. 4. The regulation means 91 furthermore comprise a determination module 93 for the reactive power, based on the measured voltages Vmes and on the currents. measured Imes, and a fuzzy logic processing module 94 for determining the values of the minimum target Vminl and maximum Vmaxl limits, from the reactive power Q exchanged and the measured voltage Vmes.

As shown in FIG. 10, in more detail, the values of the minimum target limits Vmin1 and maximum Vmax1 are determined by multiplying the difference between the limits of eligibility, respectively minimum Vmin2 and maximum Vmax2, and a minimum nominal value of the voltage by a coefficient K determined by the fuzzy logic process, the input variables of said process being the measured voltage Vmes and the reactive power Q exchanged. The values of the target limits can therefore be determined as follows: V _{min X} = K * (l - V _{min 2} ) + lpu

The fuzzy logic processing module 94 of FIG. 10 comprises:

a module 101 for determining normalized values Vn and Qn of the measured voltage Vmes and the reactive power Q exchanged, a module for determining a coefficient K from said normalized values,

a module for determining the deviations between the minimum admissibility limits Vmin2 and maximum Vmax2, and a nominal value of the voltage lpu, and

a module for determining the differences between the minimum target limits Vmin1 and the maximum value Vmax1, by multiplying the differences between the limits of eligibility, respectively minimum Vmin2 and maximum Vmax2, and the nominal value lpu of the voltage by the coefficient K determined by the fuzzy logic process.

As shown in FIG. 11, the regulation method comprises a first step 31 for measuring the voltage Vmes and the current lmes at the point of connection of the decentralized energy production device to the network. The reactive power is then determined during a step 32.

In order to determine the values of the minimum target limits Vmin1 and maximum Vmax1, the control method according to an example of this second embodiment comprises a step 111 of normalizing the input variables that constitute the measured voltage Vmes and the power In this normalizing step, a normalized voltage Vn is determined as a function of the measured voltage and the voltage permeability limits Vmin2 and Vmax2. In the same way, a normalized reactive power Qn is determined as a function of the reactive power Q exchanged and absorbed reactive power limits Qmin and reactive power output Qmax.

Once this preliminary normalization step has been completed, the values of the minimum target limits Vmin1 and maximum Vmax1 are determined from the coefficient K determined by fuzzy logic processing comprising a step 112 for determining the membership functions, a step 113 of inference and a step 114 of determining the output of the supervisor. During the step 112 of determining the membership functions, membership functions are created in order to transform the input variables that constitute the measured voltage and the reactive power exchanged into linguistic variables corresponding to each membership function. For each value of the input variables, it is thus possible to define a degree of membership in one or several membership functions. Each membership function can have, for example, the shape of a bell or a triangle. Functions having a bell shape are preferred. In the inference step 113, a logical relationship between the input variables and at least one output of a supervisor is defined using an inference table. Thus for each pair of values of the two input variables are determined fuzzy output laws. In step 114 of determining the output of the supervisor, the output value of the supervisor, ie the coefficient K, is determined according to the values of the input variables. The graphical representation of FIG. 12 illustrates the variation of the coefficient K as a function of the input variables constituted by the measured voltage and the reactive power exchanged. In step 115, the values of the minimum target limits Vmin1 and maximum Vmax1 are determined according to the coefficient K as previously described.

The measured voltage Vmes is then compared with the limits Vmin1 and Vmax1 of the target voltage range by comparison steps 33 and 34. As long as the measured voltage is within the target range, the reactive power regulation is implemented, in a step 35, to maintain the reactive power produced or absorbed substantially constant. When the voltage is outside the target range, the voltage regulation is implemented under the same conditions as in the first embodiment of the invention. For simplicity, the voltage regulation is represented by steps 116 and 117, depending on whether the distributed power generation device absorbs or produces reactive power.

Simulation of the second embodiment of the invention.

In a third simulation, the decentralized energy production devices are equipped with mixed regulation means according to the second embodiment of the invention, ie operating with respect to a variable voltage target range. Thus, in this third simulation, the minimum target limits Vmin1 and maximum Vmax1 are regularly determined, for example calculated iteratively, by the fuzzy logic iterative process described above.

The "3 ^rd simulation" column of the table of FIG. 14 shows that the voltage on all the points of the distribution network is, as during the second simulation, confined within the voltage eligibility limits. The implementation of the regulation according to this second embodiment of the invention thus also makes it possible to limit the voltage variations at any point of connection of the distribution network and to create a synergistic effect between the various devices provided with the means of connection. regulation according to this second embodiment. Variations of the voltage as a function of time at the point of connection corresponding to node 11 of the network, represented in FIG. 15 by curve 153, shows that the voltage has indeed been reduced within the range of eligibility.

As shown by the curve 163 in FIG. 16, it is observed that the voltage has been reduced within the limits of voltage eligibility by varying the reactive power produced, between 1 and 20 seconds, or the reactive power. absorbed, between 80 and 90 seconds. However, unlike the second simulation, the variations of the reactive power Q were performed without reaching the maximum limits Qmax or minimum Qmin of the reactive power exchanged. Thus, during these two episodes, the regulation operates in voltage regulation mode without affecting the active power. The regulation according to the second embodiment thus makes it possible, not only to maintain the overall voltage plan of the network, but also to maintain the active power available at each point of the network.

As shown in FIG. 17, during these two episodes in which there is a significant variation in the reactive power exchanged, the limits of admissibility Vmin1 and Vmax1, respectively represented by time-related curves referenced numerically 171 and 172, were respectively increased and reduced to values tending towards the network's admissibility limits.

In general, the regulations according to the invention can be implemented by any means known to those skilled in the art, for example by means of an analog or digital controller, possibly using the fuzzy logic technique.

Optionally, it is possible to provide a backup mode in which the control device according to the invention switches from the reactive power control mode in voltage regulation mode, in one direction or the other. The regulating device according to the invention makes it possible to maintain the voltage at the connection point within the desired limits and to improve the quality of the voltage supplied by the decentralized energy production device for the different operating modes. It also makes it possible to improve the performance of decentralized energy production devices and to reduce voltage variations in steady state or slow transient conditions.

The regulation method of the invention improves the performance and increase the penetration capacity of the decentralized energy production device on the distribution network.

The regulation method of the invention can be implemented without using communication means between the decentralized energy production devices and a network manager. Thus, the connection cost of a decentralized energy production device is reduced, and the control and management plan of the distribution network is simplified.

The regulation method of the invention allows automatic operation and to completely overcome any prior optimization. Thus, the regulation can adapt to load variations and to the implementation of other decentralized energy production devices, at different points of the distribution network.

The regulation device according to the invention can be set to operate in network connected mode, and possibly in islanding mode. It is particularly suitable for decentralized energy production devices of rotating machine type equipped with an excitation device, or for decentralized energy production devices connected to the network via a DC / AC, AC / AC or AC converter / DC / AC, for example devices of the wind, photovoltaic, microturbine or fuel cell type.

The regulation method according to the invention is adapted to different power ranges of decentralized energy production device, and in particular to those connected to the low and medium voltage network.

Claims

A control method for a distributed power generation device connected to a distribution network comprising:

a measurement of voltage (Vmes) and of current (Imes) at a point of connection to the network of the decentralized energy production device,

A power regulation exchanged by the decentralized energy production device, when the measured voltage (Vmes) is within a target range between a minimum target limit (Vmin1) and a maximum target limit (Vmax1), said target range being within a permissible range of the mains voltage, and - a regulation of the voltage at the connection point of the production device

. decentralized energy supply in which the decentralized energy production device is operated so as to: 1) absorb reactive power (Q) when the measured voltage (Vmes) is greater than the maximum target limit (Vmaxl), 2 ) produce reactive power (Q) when the measured voltage (Vmes) is less than the minimum target limit (Vminl),

3) reducing the active power (P) produced when the reactive power absorbed by the distributed anenergy generating device has reached an absorbed reactive power limit (Qmin), and 4) increasing the active power (P) produced when the power generated by the distributed power generation device has reached a reactive power output limit (Qmax), characterized in that the regulation of the voltage by reduction of the active power (P) produced is performed when the measured voltage (Vmes ) is greater than a maximum eligibility limit (Vmax2), and that the voltage regulation by increasing the active power produced is performed when the measured voltage (Vmes) is below a minimum eligibility limit (Vmin2 ).

2. Method according to claim 1, characterized in that the minimum (Vminl) and maximum (Vmaxl) target limits are fixed.

3. Method according to claim 2, characterized in that the regulation of the voltage comprises a voltage regulation loop by absorption or reactive power production comprising the determination of a voltage difference (E) between the measured voltage (Vmes) and a voltage setpoint (Vcons) and the variation of the reactive power (Q) absorbed or produced by a fuzzy logic process, the input variables of said process being said voltage difference (E) and the function derived from said difference by relation to time (dE / dt).

4. Method according to claim 2, characterized in that the regulation of the voltage comprises a reactive power absorption voltage regulation loop comprising the determination of a difference (Emax) between the measured voltage (Vmes) and the target limit. maximum (Vmaxl), and the variation of the reactive power (Q) produced by an integral proportional correction (PI) of said difference (Emax) with a saturation of the reactive power between the reactive power absorbed limit (Qmin) and zero.

5. Method according to claim 2, characterized in that the regulation of the voltage comprises a voltage regulation loop by reactive power production comprising determining a difference (Emin) between the measured voltage (Vmes) and the target limit. minimum (Vminl), and the variation of the reactive power (Q) absorbed by an integral proportional correction (PI) of said difference (Emin) with a saturation of the reactive power between zero and the reactive power output limit (Qmax).

6. Method according to one of claims 4 or 5, characterized in that it comprises the determination of parameters (Ki and Kp) of the integral proportional correction by a fuzzy logic process, the input variables of said process being difference (Emax) between the measured voltage (Vmes) and the maximum target limit (Vmaxl) and / or the difference (Emin) between the measured voltage (Vmes) and the minimum target limit (Vminl), and the derivative of said deviations (Emax or Emin) with respect to time (dE / dt).

7. Method according to claim 1, characterized in that it comprises the determination, automatically and adaptively, values of the minimum (Vminl) and maximum (Vmaxl) target limits of said target range, as a function of the measured voltage ( Vmes) and / or the reactive power (Q), the value of the maximum target limit (Vmaxl) being kept lower than or equal to the maximum admissibility limit (Vmax2) and the value of the minimum target limit (Vminl) being maintained higher or equal to the minimum eligibility limit (Vmin2).

8. Method according to claim 7, characterized in that it comprises:

- increasing or maintaining at a substantially constant value the value of the maximum target limit (Vmaxl), when the measured voltage (Vmes) increases and / or when the reactive power (Q) absorbed increases, - the decrease or the maintaining at a substantially constant value the value of the maximum target limit (Vmaxl), when the measured voltage (Vmes) decreases and / or when the reactive power (Q) absorbed decreases,

decreasing or maintaining at a substantially constant value the value of the minimum target limit (Vmin1), when the measured voltage (Vmes) decreases and / or when the reactive power (Q) produced increases, or

- increasing or maintaining at a substantially constant value the value of the minimum target limit (Vminl), when the measured voltage (Vmes) increases and / or when the reactive power (Q) produced decreases.

9. The method of claim 8, characterized in that the maximum target limit (Vmaxl) or minimum (Vminl) is increased or decreased in one or more steps.

10. Method according to one of claims 8 or 9, characterized in that it comprises maintaining the values of the target limits (Vminl, Vmaxl) to substantially constant values, when the measured voltage (Vmes) and the reactive power ( Q) are distributed in a zone, of a voltage and reactive power plane, extending along an axis passing through a first point corresponding to the minimum admissibility limit (Vmin2) and the reactive power limit absorbed (Qmin), and a second point corresponding to the maximum eligibility limit (Vmax2) and the reactive power limit produced (Qmax).

11. Method according to one of claims 8 to 10, characterized in that the values of the minimum (Vminl) and / or maximum (Vmaxl) target limits are determined by fuzzy logic processing.

12. Method according to claim 11, characterized in that the values of the minimum (Vminl) and maximum (Vmaxl) target limits are determined by calculating the differences between said target limits and a nominal value of the voltage (lpu) by the following steps :

the determination of a coefficient (K) by a fuzzy logic process from the measured voltage (Vmes) and the reactive power (Q) absorbed or produced,

the determination of the differences between the minimum (Vmin2) and maximum (Vmax2) eligibility limits, and a nominal value of the voltage, and

- the determination of the deviations between the minimum (Vminl) and maximum (Vmaxl) target limits, and the nominal value of the voltage, by multiplying the differences between the limits of eligibility, respectively minimum (Vmin2) and maximum (Vmax2), and the nominal value of the voltage by the coefficient (K) determined by the fuzzy logic process.

13. Control device for a decentralized power generation device connected to a distribution network comprising:

means for measuring voltage (Vmes) and current (Imes) at a point of connection to the network of the decentralized energy production device,

power regulation means exchanged by the decentralized energy production device, said power regulation means being implemented when the measured voltage (Vmes) is within a target range between a target limit minimum (Vminl) and a maximum target limit (Vmaxl), said target range being within a range of eligibility of the network voltage, and

means for regulating the voltage at the connection point of the decentralized energy production device, said voltage regulation means being implemented when the measured voltage (Vmes) is outside the target range, by acting on the decentralized energy production device so as to absorb or to produce reactive power (Q), and / or to reduce or increase the active power (P) produced, characterized in that the regulation of the voltage by reduction of the active power (P) produced is realized when the measured voltage (Vmes) is greater than a maximum admissibility limit (Vmax2), and the regulation of the voltage by increasing the active power produced is performed when the measured voltage (Vmes) is below a limit minimum eligibility (Vmin2).

14. Device according to claim 13, characterized in that it comprises a processing unit dedicated to the determination of the values of the minimum (Vminl) and maximum (Vmaxl) target limits of said target range, as a function of the measured voltage (Vmes ) and / or the reactive power (Q).

15. Device according to claim 14, characterized in that the processing unit dedicated to the determination of the values of the minimum (Vminl) and maximum target limits

(Vmax1) is a fuzzy logic processing module (94).

16. Device according to claim 15, characterized in that the fuzzy logic processing module (94) comprises: a module for determining (101) normalized values (Vn and Qn) of the measured voltage (Vmes) and the reactive power (Q) absorbed or produced,

a module for determining (102) a coefficient (K) from said normalized values,

a module for determining (103) the differences between the minimum (Vmin2) and maximum (Vmax2) eligibility limits, and a nominal value of the voltage

(lpu), and

a module for determining (104) the differences between the minimum (Vmin1) and maximum (Vmaxl) target limits, and the nominal value of the voltage, multiplying the differences between the minimum and maximum (Vmin2) and maximum permissible limits of eligibility; (Vmax2), and the nominal value (lpu) of the voltage by the coefficient (K) determined by the fuzzy logic process.

17. Installation comprising an electricity distribution network and at least two decentralized energy production devices connected to said network, characterized in that each of said at least two decentralized energy production devices is provided with a regulation device according to one of claims 13 to 16 implementing:

power regulation means exchanged by the decentralized energy production device, and voltage regulation means at the connection point of the decentralized energy production device.