WO2017089513A1

WO2017089513A1 - System and method for controlling the voltage and frequency of an isolatable network

Info

Publication number: WO2017089513A1
Application number: PCT/EP2016/078766
Authority: WO
Inventors: Boris DENEUVILLE
Original assignee: Electricite De France
Priority date: 2015-11-25
Filing date: 2016-11-25
Publication date: 2017-06-01
Also published as: FR3044174A1; FR3044174B1

Abstract

The invention concerns a system (3) for controlling an amplitude and a frequency of a voltage delivered on a network (1) that can be isolated from a main network (2), and comprising an unregulated electricity production device (10) and a consumption load (12), characterised in that it comprises: - two control loads (30, 31), suitable for consuming or producing, respectively, an active and reactive power that vary depending respectively on an active power setpoint value and a reactive power setpoint value, - a control unit (33), comprising: o at least one sensor (34) for measuring the amplitude and the frequency of the voltage delivered to the consumption load, o a processor (35) suitable for delivering, to the control loads, based on the measurements of the sensors, active power and reactive power setpoint values, and in which the control laws comprise at least one control law determining the active power setpoint values from the amplitude measurements of the measured voltage, and the reactive power setpoint values from the frequency measurements of the measured voltage.

Description

SYSTEM AND METHOD FOR VOLTAGE REGULATION AND FREQUENCY OF A

ISOLABLE NETWORK

FIELD OF THE INVENTION

The invention relates to a system for regulating the amplitude and the frequency of the electric voltage delivered on a network comprising an unregulated electricity generating device, and which can be isolated from an upstream network provided with a device for generating electricity. regulated electricity.

The invention also relates to a control method implemented with such a system.

STATE OF THE ART

Some isolated locations, such as mountainous areas or islands, have power grids that may be isolated from a public grid (or backbone) in certain circumstances, such as in difficult weather conditions incident on the main power grid.

In isolation, local energy resources can be used to maintain power generation in the isolated network. However, such a network must have a voltage whose amplitude and frequency are regulated.

Some sources of electricity production are able to produce a voltage whose amplitude and frequency are regulated; this is the case, for example, of generators equipped with synchronous generators and voltage and frequency regulators, or sets comprising photovoltaic panels, batteries, inverters, and voltage and frequency regulators.

These means of production are expensive, so most electricity distribution networks do not have them. On the other hand, many distribution networks are equipped with unregulated power generation means, for example wind turbines, photovoltaic panels without control systems, and so on. However, these means do not make it possible to meet the requirements of the electrical consumption loads concerning the amplitude and the frequency of the electrical voltage delivered on the network. In addition, these means of production can produce energy only after having been connected to an already undervoltage network, that is to say that they are not themselves capable of powering a power supply. network initially off.

To solve this problem, in the case where the production means is equipped with an asynchronous generator, for example document FR 2 437 105 is known which describes a means of initiating the operation of a generator by capacitor banks. However, this document does not make it possible to regulate the amplitude and the frequency of the voltage after the priming. Also, documents FR 2 481 857, FR 2 870 401 and FR 2 490 421 which describe means for regulating the amplitude and the frequency of the voltage of an isolated network are known, the amplitude of the voltage being regulated by the control of reactive charges, and the frequency being controlled by controlling the speed of a drive motor of the generating generator producing electricity.

In the case where the production means is equipped with a synchronous generator equipped with a regulator of the voltage and the frequency, the method used is the following one:

Frequency adjustment is achieved indirectly by controlling the speed of rotation of the generator shaft, by acting on the mechanical torque transmitted by the drive motor or the turbine to the rotor of the generator. Typically, it may be to control the injection of fuel in the case of a heat engine.

The amplitude of the voltage is adjusted by controlling the rotor excitation current amplitude, which acts on the electromotive force (emf) of the generator. This action also has the effect of modifying the reactive power transits, giving the generator an inductive or capacitive behavior.

For other sources of production, such as those connected to the network by inverters, we know for example the document "Defining control strategies for MicroGrids islanded operation" published in the journal IEEE Transactions on Power Systems (Volume: 21, Issue: 2, May 2006) proposing to emulate the behavior of synchronous machines and to control the frequency and amplitude of the voltage according to the laws: w = WQ- kp x P

V = V ₀ - kQ XQ

It's about :

to compare the value of the frequency with a reference value, and, depending on the difference, to inject more or less active power - to compare the value of the amplitude of the voltage with a reference value and, in function of the difference, to inject more or less reactive power.

With the addition of an integral correction, the regulation schemes are those illustrated in the appended FIG. 1 in which:

Mf denotes a measurement of the frequency,

- Fr designates a reference frequency,

- Cpa denotes an active power setpoint,

- Mt denotes a measurement of the voltage,

Tr represents a reference voltage,

- Cpr denotes a reactive power setpoint.

In the same way, on electrical networks whose size allows it, like public networks, the adjustment of the amplitude of the voltage is done locally by controlling the transits reactive power because the lines are essentially inductive and reactive power transits create rises and drops in tension along them.

More generally, concerning all the known methods of regulation of the amplitude of the voltage and the frequency, one speaks of couples:

- frequency / power: active power generation as a function of frequency deviations in the network;

- voltage / reactive amplitude: reactive power production is a function of voltage amplitude differences in the network.

It should be noted that on the electrical networks, an imbalance between the active powers produced and consumed causes a variation of the frequency, in particular if the network has rotating machines, but also the amplitude of the global tension, that is to say ie at the scale of the entire network. In Moreover, as previously stated, the reactive power transits generate local variations of voltage amplitude.

As a result, the principle of frequency / power regulation and voltage / reagent amplitude works on most current networks.

On a wide area network, the frequency, overall magnitude, is regulated by modulating the outputs of the plants, and the amplitude of the voltage is regulated locally. Considering, for example, an increase in the load, there is a decrease in the frequency and amplitude of the overall voltage. The two regulations are then solicited:

- the active power regulators increase the power productions, modifying the frequency and the amplitude of the voltage the regulation of the amplitude of the tension contribute at the same time to correct the values of the amplitude of the tension

The combined action of the controls will thus converge the system to a new state of equilibrium in which the amplitude of the voltage and the frequency are back to the desired values.

It is noted that, although the initial imbalance concerns only an imbalance in active powers, the regulations acting on the reactive power have also been solicited.

This regulation principle may not work on certain types of networks, characterized by their size and by the types of means of production they contain.

If, for example, an active power imbalance causes a frequency variation in the direction opposite to that observed with synchronous generators, even by inverting the frequency / power setting coefficients, the system may not converge to a new one. steady state.

For example, consider an asynchronous generator driven in rotation by a heat engine whose mechanical power produced is constant, or called "ribbon". The generator feeds a resistive load and is self-excited by a bank of capacitors. Figure 2 shows such a device.

In this figure 2:

- Mth designates a heat engine,

- Am denotes a mechanical shaft,

Gr designates an asynchronous generator, - Bc denotes a bank of capacitors,

- Re designates the electrical network, and

- Cr denotes a resistive load.

The electrical part can be represented by the equivalent single-phase diagram shown in FIG. 3.

E and φ represent the electromotive force of the generator, Lm is the magnetising inductance of the asynchronous generator, Lcc is its short-circuit impedance. R represents the consumption load, and C represents the capacitor bank.

The value of the load is suddenly increased, which corresponds to a decrease in the value of the resistance. The first moments after the addition of the load, the frequency will tend to decrease, because of the increase of the resistant torque related to the increase of the current. In the same way, the amplitude of the voltage drops.

Lm, the magnetising inductance, is nonlinear, that is to say that its reactance is a function of the amplitude of the voltage. Therefore, the variations of the amplitude of the voltage and of the frequency generate a non-linear evolution of the reactive power consumption. Following the addition of the load, the frequency and the amplitude of the voltage of the system evolve towards equilibrium values. The equilibrium frequency depends on the value of Lm at the equilibrium voltage.

Therefore, according to the characteristic of the magnetising inductance, the equilibrium frequency may be higher or lower than the initial value.

FIG. 4 shows the variations of the frequency on the left and the amplitude of the voltage on the right, for two characteristics of the magnetising inductance.

In the case where the frequency increases after adding the charge, the regulation principle explained above does not work.

In addition, in this configuration, or more generally on small networks where the voltage on the network is more a global magnitude than local, the amplitude of the voltage does not vary according to the balance of reactive powers. This regulation principle does not work.

More generally, on small networks where the amplitude of the voltage on the network is more a global magnitude than local, this principle of regulation is not optimal because the voltage / power dependence is very pronounced.

So, the documents cited do not solve the problem of the priming of the isolated network, and more they require for some to double the generator of electricity by a motor whose speed is controlled to regulate the frequency.

Also, the regulations of the prior art do not work on certain types of network or are not optimal.

PRESENTATION OF THE INVENTION

The invention aims to overcome the disadvantages of the prior art described above.

In particular, an object of the invention is to propose a system for regulating the amplitude and the frequency of a voltage delivered on an autonomous network, which allows both the initiation of the network as well as its regulation in regime. stabilized, and this regardless of the laws linking magnitude of voltage and frequency to transits of active and reactive power.

Another object of the invention is to enable the frequency of the voltage to be regulated without the need for a motor to drive the electricity generating device.

In this regard, the subject of the invention is a system for regulating an amplitude and a frequency of an electric voltage delivered on a network comprising an unregulated electricity generating device and at least one consumption charge. electricity, said network being capable of being isolated from a main network, the system being characterized in that it comprises:

a first regulation load, adapted to consume or produce a variable active power as a function of an active power setpoint value,

a second regulating load, adapted to consume or produce a variable reactive power as a function of a reactive power setpoint, and

a control unit, comprising:

at least one sensor adapted to measure:

^■ the amplitude of the voltage delivered to the consumption load, ^■ the frequency of the voltage delivered to the consumption load,

a processor adapted, from the measurements of the sensors, to deliver to the control loads active and reactive power setpoint values, and in which the control laws comprise at least one control law determining the setpoint values of active power from the measurements of the measured voltage amplitude, and the reference values of the reactive power from the measurements of the frequency of the measured voltage.

Advantageously, but optionally, the system according to the invention may further comprise at least one of the following characteristics:

the first regulating load comprises at least one variable resistor, and the second regulating load comprises at least one capacitor of variable capacitance.

The control system further comprises a load adapted to consume or produce a fixed reactive power.

The processor is further adapted to implement a plurality of control laws of the active power and reactive power setpoint values, and to select a control law to be implemented according to an initial state of the network among the next group:

o the network is de-energized and isolated from the upstream network,

o the grid is live and isolated from the upstream network, and

o The network is live and connected to the upstream network. The system further comprises a load adapted to consume or produce a fixed reactive power, wherein the control laws comprise at least one control law determining the active power and reactive power setpoint values from a phase shift measurement. between the voltage and the current and from a measurement of voltage amplitude or voltage frequency delivered to the consumption load.

The invention also relates to a method of regulating an amplitude and a frequency of an electric voltage delivered on a network comprising an unregulated electricity generating device and at least one load of consumption of electricity, said network being capable of being isolated from a main network, the method being characterized in that it is implemented by a control system according to the preceding description, and in that it comprises :

the detection of an initial state of the network,

from the initial state of the detected network, the selection of at least one control law of reactive power setpoint values and of active power to be applied to the regulation loads to regulate the amplitude and the frequency of the voltage on the network, and wherein the control laws comprise at least one control law determining the active power setpoint values from the measurements of the amplitude of the measured voltage, and the reference values of the reactive power to from measurements of the frequency of the measured voltage.

Advantageously, but optionally, the control method according to the invention may further comprise at least one of the following features: the method is implemented in a control system further comprising a generator, and, if the state network is off and isolated from the main network, the method includes:

o powering up the network by the generator, o controlling the active and reactive power loads to fixed setpoints,

o the connection of the unregulated electricity generating device, and

o the disconnection of the generator and the control of the active and reactive power loads according to a regulation control law in steady state.

The method is implemented in a control system comprising an islanding contactor adapted to selectively connect or disconnect the network to the main network, and wherein, if the initial state of the network is undervoltage and connected to the upstream network, the method comprises:

o the control of the active and reactive power loads at setpoint values respectively of the active power and the reactive power passing through the islanding contactor,

o the opening of the island contactor, and the control of the active and reactive power loads according to a regulation law under steady state conditions.

If the initial state of the network is undervoltage and disconnected from the upstream network, the method comprises the control of the active and reactive power loads according to a steady-state regulation law.

The invention also relates to a control method implemented by such a system.

The proposed control system includes a regulating load that can consume or produce variable active power, a regulating load that can consume or produce variable reactive power, and a control unit that can control these regulating loads to regulate both the amplitude of the voltage and the frequency of the voltage delivered on the autonomous network.

This system can regulate the amplitude and frequency of the voltage in different states in which the network may be. In particular, it makes it possible to initiate the powering on of the network when it is initially disconnected from a main network and off, or it also makes it possible to isolate the isolable network of the main network, without generating a power cut. .

This system also makes it possible to provide steady-state regulation, in which the network is isolated from the main network and yet energized, to meet the requirements for consumption of loads such as domestic electrical equipment.

In addition, the control unit can, when the network is isolated from the main network and under tension, implement different control laws of the set values to be given to the regulation loads, according to pre-recorded scenarios. This makes it possible to choose the optimal control law, as a function, for example, of the technologies selected for the regulation loads and the requirements of the consumption load on the voltage and the frequency in terms of accuracy and speed of regulation.

DESCRIPTION OF THE FIGURES

Other features, objects and advantages of the present invention will appear on reading the detailed description which follows, with reference to the appended figures, given by way of non-limiting examples and in which: FIG. 1 schematically represents a conventional control scheme known from the state of the art,

FIG. 2 represents a known installation comprising an asynchronous generator driven by a heat engine, supplying a resistive load and self-excited by a bank of capacitors,

FIG. 3 represents an equivalent single-phase diagram of the installation illustrated in FIG. 2,

FIG. 4 represents the frequency and voltage amplitude variations for two characteristics of magnetising inductance illustrated in FIG. 3,

FIG. 5 diagrammatically represents a control scheme according to the present invention,

FIGS. 6a and 6b show a control system according to two embodiments of the invention,

FIGS. 7a and 7b show equivalent electrical diagrams of a control system according to two variant embodiments of the invention. FIG. 8 schematically represents the main steps of a control method implemented by the system.

FIG. 9 represents a general regulation scheme implemented in the context of the invention.

GENERAL REGULATION SCHEME IN ACCORDANCE WITH THE PRESENT INVENTION

As illustrated in FIG. 5 appended, according to the invention a frequency reference value Fr is compared with a frequency measurement value Mf to determine, with the addition of an integral correction, a power reference value. reactive, Cpr, and a voltage amplitude value, Tr, is compared with a voltage amplitude measurement value Mt to define, also with the addition of an integral correction, an active power setpoint value Cpa.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

Regulation system

Referring to Figures 6a and 6b, there is shown schematically a control system 3 of an isolable network 1, also called micro network or microgrid, with unregulated power generation means. The isolable network 1 comprises at least one unregulated electricity generator 10, which may be of the photovoltaic panel, wind turbine, gas generator, etc. type. No generator 10 is provided with regulation means dedicated to controlling the amplitude or the frequency of the voltage at its terminals. The generators 10 are therefore normally provided to supply electricity to a main network 2 or upstream network, which in turn has regulation means and regulated electricity generation means.

The isolable network may also include auxiliary electrical charges 1 1, which are typically the auxiliaries of the generators 10, such as pumps belonging to a gas generator, or the control equipment required for its operation. To start the generators 10 it is therefore necessary to give these loads 1 1 the active and reactive powers they require.

Finally, the network 1 may also include an electrical generator 12 adapted to power up the network when it is initially off, and maintain the frequency and amplitude of the voltage within acceptable ranges of values. Typically this generator is a generator 12.

The generators 10, 12 and the auxiliary charges 1 1 are preferably grouped together in a so-called central zone Z.

The isolable network 1 also comprises consumption charges 13 arranged in a so-called consumption zone Z ', typically particular customers having domestic equipment. These charges are adapted to consume active power and to consume or produce reactive power.

The central zone Z is electrically connected to the consumption zone

Z 'by an interzone electrical link 14. In some cases, as shown in FIG. 6b, the consumption zone Z' may also comprise an unregulated electricity generator 10. This does not prevent the regulation described below.

In addition, when the isolatable network 1 can be selectively connected to the upstream network 2 (shown in FIG. 6a) or disconnected from it, this selective connection is made by an islanding contactor 15 (shown in FIG. 6a).

The regulation system 3 makes it possible to regulate the amplitude and the frequency of the voltage delivered by the generator (s) 10 of the network 1. For this purpose, it includes a first regulation load 30 adapted to consume or produce a variable active power.

This regulation load 30 may comprise for example one or more resistors, the resistances being variable and / or connected to the network 1 by means of a power electronics or a transformer with on-load tap changer. The regulating load 30 may also be an inverter battery system.

The active power consumed or produced by this first regulation load can be controlled with a setpoint ΔΡ.

The regulation system 3 comprises a second regulating load 31, adapted to consume or produce a variable reactive power. This load 31 may comprise, for example, one or more capacitors of variable capacitance, power electronics components such as inverters, or a synchronous compensator.

The reactive power consumed or produced by this second regulation load 31 can be controlled with a setpoint ΔΟ.

Advantageously, but optionally, the control system may further comprise a fixed reactive load 32, consuming or providing a fixed reactive power Q _f .

The control system further comprises a control unit 33, adapted to deliver to the regulating loads 30, 31 the appropriate setpoint values on the active power and the reactive power in order to regulate the amplitude and the frequency of the voltage on the network.

In this respect, the control unit 33 comprises at least one sensor 34, adapted to measure:

the amplitude U of the voltage delivered by the generator 10 to the consumption load 13, and

the frequency f of the voltage delivered by the generator 10 to the consumption load 13.

As can be seen in FIGS. 6a and 6b, these measurements can be performed at the level of the interzone electrical link 14.

Advantageously, the sensor (s) 34 of the control unit 33 are also adapted to measure the active power Pi and the reactive power Qi passing through the islanding contactor 15. Advantageously, in the case where the network 1 comprises a generator 12, the sensors 34 of the control unit are also adapted to measure the active power P _G E and the reactive power Q _G E produced by the group 12.

In addition, the control unit 33 comprises processing means, typically a processor 35, and a memory 36, shown only in Figure 6a. The processor 35 is adapted to receive the measurements of the sensors 34 and, from these measurements, to send to the control loads 30, 31, setpoints ΔΡ, ΔΟ. on active power and reactive power to regulate the amplitude and frequency of the voltage on the network.

To do this, the processor 35 is adapted to selectively execute a plurality of control laws A, B, C, D, E or F, which are stored in the memory 36. Each control law determines a set value respectively for the active power ΔΡ, and for the reactive power ΔΟ. according to respective input parameters a and b separately.

We have AP = f (a) and AQ = f (b).

The control laws A to F have different input parameters which will be described in more detail below.

The control law executed among the various available laws is chosen by the processor according to the initial state of the network 1 as well as the circumstances of the regulation.

Network 1 can be in one of the following initial states:

it is off-line and disconnected from the main network; the islanding contactor 15 is open. This is typically the case when the network connection 1 is accidentally cut off from the main network 2.

The network 1 is under-voltage and connected to the main network 2; the island connector 15 is closed. This is the case when the network 1 is still powered by the main network and it is desired to disconnect it from this network without generating a power cut.

- Network 1 is under-voltage and disconnected from the main network; the islanding contactor 15 is open. This is the case when the generation of electricity has been started by the generator 12 to restore the voltage after a cutoff of the network connection 1 to the main network 2. With regard to the first two initial states described above, the control system makes it possible to pass the network 1 of one of these initial states to a stabilized state in which the network 1 is under-voltage t disconnected from the main network, which corresponds to the third state described above. Then the control system 3 is adapted to maintain the network in this state by regulating the frequency and amplitude of the voltage to meet the requirements of the electrical charges.

In this respect, the control laws comprise four steady-state control laws A, B, C, D, allowing the system to regulate the amplitude and frequency of the voltage on the network once it is energized. , and two transient state control laws E and F, allowing the system to bring the network from an initial state to a state in which it is energized and disconnected from the main network. The details of the control laws are described in more detail below.

Finally, the processor 35 is advantageously adapted to control actuators (not shown) to open and close the islanding contactor and open and close contactors for connecting the generators 10, the generator 12, and the regulating loads 30, 31 to the network 1.

Regulation process

With reference to FIG. 8, the main steps of the regulation method implemented by the system 3 above are schematically represented.

The method comprises a first step 100 of detection of an initial state of the network by the control unit 33. This step is implemented for example by measuring the amplitude of the voltage on the network 1 and by measuring the values of the active and reactive power Pi and Qi crossing the island contactor 15.

If the voltage in the network is zero, then the initial state is off state 1, disconnected from the main network 2.

If the voltage in the network is non-zero, and a non-zero active and / or reactive power passes through the islanding contactor, then the initial state is the state 120 under voltage and connected to the main network 2.

If the voltage in the network is non-zero, but the active and reactive power passing through the islanding contactor is zero, then the initial state is the state 130 under voltage and disconnected from the main network.

The method then comprises a regulation step 200 as a function of the initial state of the network 1 detected in the previous step. When the initial state is off state 1 and disconnected from the main network 2, the network 1 must be re-energized before being stabilized. Consequently, the regulation step 200 comprises a first step 210 for connecting the generator set 12 to the grid and for starting the generator set so that it can power up the network 1.

This brings the amplitude and the frequency of the voltage delivered by the generator set to determined values. As a result, the generator set 12 generates active power P _G E and reactive power Q _G E

In order to then connect the unregulated electricity production sources 10 to the network, the control unit 33 connects 21 1 the active and reactive regulation charges 30 to the network, and the processor implements 212 a control law E, wherein the active and reactive power setpoint values ΔΡ, ΔΟ are fixed and independent of the other magnitudes of the network. In other words, this control law has no input parameters a and b.

The control unit 33 then connects the unregulated electricity generator (s) to the grid and turns them on. In this way, the generators produce a growing active power.

To maintain the balance of the active powers produced and consumed on the network 1, the generator will decrease the active power it produces. Once the active power produced by the generator passes below a predetermined threshold stored in the memory 36, the control unit disconnects the generator 214.

The network is in the undervoltage state and disconnected from the main network 2, which corresponds to the initial state 130 introduced above.

The amplitude and the frequency of the voltage are then regulated by the implementation of one of the control laws A, B, C, or D described in more detail below.

When the initial state of the network 1 is the state 120 under voltage and connected to the main network 2, the network 1 must be disconnected from the main network 2 without generating a cutoff.

The regulation step 200 comprises a first step 220 for connecting the active and reactive regulation loads 31 to the network by the control of their respective contactors. The processor 35 of the control unit then implements 221 a control law F. This control law delivers the active and reactive power setpoints ΔΡ, ΔΟ. as a function of the active power values Pi and reactive Qi passing through the islanding contactor 15 and measured by the sensors 34. The control law adjusts the values of the setpoints to converge the active power Pi and reactive Qi through the island contactor towards 0.

For this law F we have ΔΡ = ί (Ρ,) and AQ = f (Q,)

For example, the control law can increase the active power consumed by the regulating load 30 to reduce or increase the active power passing through the islanding contactor 15, depending on the direction in which the active power passes through the islanding contactor.

When the control unit 33 detects, by means of the sensors 34, the moment when the active power Pi and reactive Qi passing through the islanding contactor passes under a predetermined value, it controls 222 the islanding contactor 15 to isolate the network 1 of the main network 2.

The network is then in the energized state and isolated from the main network 2 which corresponds to the initial state 130 introduced above.

Finally, when the state of the network 1 corresponds to the state under voltage and isolated from the main network 2 - whether this is an initial state or a state reached after the implementation of the control laws E or F, the processor 35 of the control unit 33 is adapted to implement 230 a control law among the laws A, B, C, and D. Each of these laws aims to regulate the amplitude and frequency of the voltage delivered by the Unregulated electricity generator 10, that is to say to converge the amplitude of the voltage U to a predetermined value U ₀ and to converge the frequency f to a predetermined value f ₀ .

To achieve these convergences, each control law modifies the setpoints ΔΡ and ΔΟ, the modification of each setpoint causing variations of the parameters U, f and a, with the phase shift between the voltage and the current.

At a given moment, a single control law is implemented by the processor 35.

Table 1 shows a summary of the control laws A to F, and the parameters from which these laws generate setpoints on the active power and the reactive power.

Table 1

The law A represents a law according to the present invention ensuring the regulation of the frequency and the voltage on the electrical networks on which the law B according to the prior art does not work or is not optimal.

FIG. 9 shows typical control schemes making it possible to implement these control laws by determining the active setpoints ΔΡ from the measurement parameter a and reactive AQ from the measurement parameter b.

Thus, for the law A, the processor 35 calculates the setpoint ΔΡ as a function of U and the setpoint ΔΟ. according to f.

For the law B, the processor 35 calculates the setpoint ΔΡ as a function of f and the setpoint ΔΟ. according to U.

For the law C, the processor 35 calculates the setpoint ΔΡ as a function of U and the setpoint ΔΟ. according to a.

For the law D, the processor 35 calculates the setpoint ΔΡ as a function of f and the setpoint ΔΟ. according to a.

Advantageously, the processor 35 selects a law among the laws A to D steady state based on pre-recorded scenarios in the memory 36, taking into account parameters such as:

Structure and operation of the active and reactive regulation loads 30

31, and

Requirements of consumption loads 13 on the accuracy of regulation, in amplitude of voltage or in frequency. For example, if the reactive regulation load 31 is formed by a step of capacitors, it does not make it possible to fine-adjust the capacitance and therefore the reactive power that it supplies or consumes, and also has constraints on time. re-engagement of the capacitors.

If the active regulation load 30 is based on power electronics, it allows fine adjustment of the resistance and therefore the active power that it consumes, and very quickly.

Therefore, if the consumption load 13 is very demanding on the amplitude of the voltage and less on the frequency, the law A according to the present invention is more appropriate than the law B because it makes it possible to respond rapidly to variations in voltage and therefore demonstrate greater accuracy.

Referring to Figures 7a and 7b, we will now detail the principle of implementation of laws A and B on the one hand, and laws C and D on the other hand, in the case where the generator 10 is an asynchronous generator .

In FIG. 7a, there is shown an equivalent electrical diagram of the isolated network 2, where E, φ L1 and Lcc represent the generator (s) 10:

E and φ represent the electromotive force of the generators,

L1 is a coil, it represents the reactive power consumption of the generators - in the case of asynchronous generators it is the magnetising inductance,

Lcc is the short-circuit impedance of the generators.

R2 and L2 represent the consumption charges 13:

R2 is a variable resistance depending on the electricity consumption of a customer,

L2 is a coil whose value of inductance varies according to the electricity consumption of a customer.

Finally, R is a resistance that represents the active power control load. The set point ΔΡ consists of changing the resistance value of R. C is a capacitor representing the reactive power control charge 31. The set point ΔΟ consists of changing the value of the capacitance of C. U is the amplitude of the voltage delivered to the consumption load 13. In such a circuit, the equilibrium voltage Ueq and the resonance frequency feq depend on the values of the resistance of R and the capacitance of C.

Thus, the control laws A and B drive the set values to adjust the resistance values of R and capacitance of C to maintain U _eq at the desired Uo, typically 400V, and f _eq at the desired f ₀ , typically 50Hz.

The control laws vary depending on the network and the nature of the regulatory loads.

In order to implement the control laws A and B, the positions of the control loads 30 and 31 are arbitrary. The control system may optionally include a fixed reactive load. In particular, the embodiments shown in FIGS. 6a and 6b make it possible to implement these control laws.

Thus, according to a nonlimiting example, as in FIG. 6a, all these charges can be connected to the network 1 in the central zone. In a variant, represented in FIG. 6b:

at least one load can be connected to the network in the central zone Z, for example the fixed load 32,

at least one load can be connected to the mains in the consumption area Z ', for example the reactive control load 31, and - at least one load can be connected to the network at the interzone electrical link 12, for example the first load regulation 30.

With reference to FIG. 7b, the equivalent electrical diagram of the insulated network 2 is again shown, in the case where the network also comprises a fixed reactive load 32 represented by a capacitor C1.

The subset consisting of the capacitor C1, the coil L1 and the coil Lcc, and delimited by dashed lines in Figure 7b, is a resonant subassembly. The capacitance of the capacitor, i.e. the reactive power supplied or absorbed by the fixed load 32, is set so that the subset resonance frequency is equal to a predetermined frequency f ₀ .

a being the phase shift between the voltage U and the current I in the network, provided, when it is not zero, information on the level of production or reactive power consumption of the consumption zone Z '. When is no, the reactive powers produced by the regulating charge 31 (capacitor C) and consumed by the consumption charge are identical.

Thus, the control laws C and D drive the setpoint value reactive power ΔΟ as a function of the measured value of the phase shift a, to maintain a to 0.

In the control law C, the active power setpoint ΔΡ is a change in the value of the resistance of R as a function of the measured value of the amplitude of the voltage to reduce this amplitude to a predetermined level U ₀ .

In the control law D, the active power setpoint ΔΡ is a change in the value of the resistance of R as a function of the measured value of the frequency f to reduce this frequency to a predetermined value f ₀ .

In order to implement the control laws C and D, the position of the regulating loads 30, 31 must respect the following constraints:

the reactive power regulation load 31 must be connected to the network in the consumption zone Z ',

the reactive fixed load 32 must be connected to the network in the central zone Z,

Finally, there must be an active power transit between the central zone Z and the consumption zone Z '.

These constraints are respected in the illustration of Figure 1 b.

The proposed control system therefore makes it possible to operate a transient isolable network to a steady state in which the network is switched on and disconnected from a main network. In addition, the regulation of the voltage and the frequency under steady state can be implemented according to different control laws, the most relevant control law being able to be chosen according to the structure of the network, the type of regulation loads and load requirements.

Claims

1. Control system (3) for an amplitude and a frequency of an electric voltage delivered on a network (1) comprising an unregulated electricity generating device (10) and at least one electricity consumption load (12), said network being capable of being isolated from a main network (2), the system (3) being characterized in that it comprises:

a first regulation load (30) adapted to consume or produce a variable active power as a function of an active power setpoint,

a second regulating load (31), adapted to consume or produce a variable reactive power as a function of a reactive power reference value, and

a control unit (33), comprising:

at least one sensor (34) adapted to measure:

^■ the amplitude of the voltage delivered to the consumption load,

^■ the frequency of the voltage delivered to the consumption load,

a processor (35) adapted, from the measurements of the sensors, to deliver to the control loads (30, 31) active power and reactive power setpoint values, and in which the control laws comprise at least one law control system determining the active power setpoint values from the measured voltage amplitude measurements, and the reactive power setpoint values from the measurements of the measured voltage frequency.

2. Control system (3) according to claim 1, wherein the first regulating load (30) comprises at least one variable resistor, and the second regulating load (31) comprises at least one capacitor of variable capacitance.

3. Control system (3) according to one of claims 1 or 2, further comprising a load (32) adapted to consume or produce a fixed reactive power.

4. Control system (3) according to one of the preceding claims, wherein the processor (35) is further adapted to implement a plurality of control laws of the set values of active power and reactive power, and to select a control law to be implemented according to an initial state of the network among the following group:

- the network is de-energized and isolated from the upstream network,

the network is live and isolated from the upstream network, and

the network is live and connected to the upstream network.

5. Control system (3) according to one of claims 1 to 4, further comprising a load (32) adapted to consume or produce a fixed reactive power, wherein the control laws comprise at least one control law determining the active power and reactive power setpoint values from a phase shift measurement between the voltage and the current and from a measurement of the voltage amplitude or voltage frequency delivered to the consumption load (13). ).

A method of regulating an amplitude and a frequency of an electric voltage delivered on a network (1) comprising an unregulated electricity generating device (10) and at least one power consumption charge ( 13), said network being capable of being isolated from a main network (2), the method being characterized in that it is implemented by a control system (3) according to one of the preceding claims, and in that it comprises:

detecting (100) an initial state of the network,

from the initial state of the detected network, the selection of at least one control law of reactive power setpoint values and of active power to be applied to the regulation loads to regulate (200) the amplitude and the frequency of the electrical voltage on the network, and in which the control laws comprise at least one control law determining the active power setpoint values from measurements of the measured voltage amplitude, and the reactive power setpoint values from the measurements of the measured voltage frequency.

7. Control method according to claim 6, implemented in a control system (3) further comprising a generator (12), and wherein, if the initial state of the network is off and isolated from the main network (2), the method comprises:

the powering of the network by the generator (210),

the control of active and reactive power loads at fixed setpoint values (21 1, 212),

the connection of the unregulated power generation device (213), and the disconnection of the generator set (214) and the control (230) of the active and reactive power loads according to a steady-state regulation control law.

8. Control method according to one of claims 6 or 7, implemented in a control system (3) comprising an islanding contactor (15) adapted to selectively connect or disconnect the network (1) to the main network ( 2), and wherein, if the initial state of the network is undervoltage and connected to the upstream network, the method comprises:

the control of the active and reactive power loads at setpoint values respectively related to the active power and the reactive power passing through the islanding contactor (221),

opening the island contactor (222), and

the control of the active and reactive power loads according to a steady-state regulation law (230).

9. Control method according to one of claims 6 to 8, wherein, if the initial state of the network is undervoltage and disconnected from the upstream network, the method comprises controlling the active and reactive power loads according to a law stabilized control system (230).