Method, system and device for regulating voltage fluctuations induced by at least one renewable energy source (general electric technology) electricity transmission costs

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The field of the invention is that of energy distribution networks having renewable energy sources connected thereto. The invention aims more particularly to reduce the effect of fluctuations in voltage level caused by fluctuations in power injections from such renewable energy sources.

Thus, the presence of distributed sources of energy generation in an energy distribution network generally leads to an increase in the amplitude of the voltage. With intermittent and variable energy sources such as renewable energy sources (solar, wind), variations in voltage become greater, more sudden, and more frequent (oscillations).

However, due to the high variability of the renewable energy that is available (e.g. a transitory effect due to a cloud passing over a photovoltaic installation), production from a renewable energy source fluctuates quickly and frequently, leading to problems of supply quality and even of voltage stability.

As a result, it appears difficult for the operators of energy distribution systems to ensure that the limits or expected values stipulated by local standards are not exceeded as a result of the sudden changes in voltage and short-term overvoltages.

With this aim in mind, the invention proposes a method of regulating voltage in an energy distribution network to which are connected both a renewable energy generation system and an electrical energy storage unit, the method being characterized in that, over a time window, a charging power of the energy storage unit is controlled so as to compensate for variations in the instantaneous voltage level induced by the renewable energy generation system relative to a prediction of the mean voltage level induced by the renewable energy generation system over said time window.

the renewable energy generation system induces an instantaneous voltage level that is a function of an instantaneous operating parameter, and the electrical energy storage unit has a power reserve that is controlled in such a manner that a charging power setpoint is increased when the instantaneous operating parameter is greater than a mean operating parameter over the time window, and the charging power setpoint is reduced when the instantaneous operating parameter is lower than the mean operating parameter over the time window;

the power reserve is controlled in such a manner that, over the time window, the variation of the charge level of the energy storage unit corresponds to an expected variation when, over the time window, the mean of the instantaneous voltage level induced by the renewable energy generation system corresponds to the predicted mean voltage level;

the charging power setpoint of the power reserve is controlled linearly as a function of the instantaneous operating parameter over a range of operating parameters that extend from a lower operating parameter to an upper operating parameter and within which the mean operating parameter is found;

the renewable energy system is a photovoltaic energy generation system, the operating parameter corresponds to insolation, the average voltage level is induced by average insolation over the time window and the instantaneous voltage level is induced by instantaneous insolation; and

The invention also provides a control device for controlling an energy storage unit designed to be connected to an energy distribution network to which is connected a renewable energy generation system that induces an instantaneous voltage level that is a function of an instantaneous operating parameter, the device being characterized in that it comprises a unit for measuring the instantaneous operating parameter and a control unit for controlling a charging power of the energy storage unit configured to receive the instantaneous operating parameter measurement and a prediction of the mean operating parameter over a time window and to act, over said time window, as a function of the difference between the measured instantaneous operating parameter and the predicted mean operating parameter, to compensate for variations in the instantaneous voltage level induced by the renewable energy generation system relative to a mean voltage level corresponding to the predicted mean operating parameter.

The invention extends to a system for regulating voltage in an energy distribution network to which are connected both at least one renewable energy generation system and at least one electrical energy storage unit, the system comprising at least one control device of the invention for controlling the at least one energy storage unit, and a central supervisor device comprising a unit for determining control parameters for the at least one control device, said control parameters comprising the predicted mean operating parameter and a rule for correcting the charging power setpoint for the energy storage unit as a function of the difference between the measured instantaneous operating parameter and the predicted mean operating parameter. BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects, objects, advantages, and characteristics of the invention appear better on reading the detailed description given below of preferred embodiments, given by way of non-limiting example, and made with reference to the accompanying drawings, in which:

Regulation is carried out at a node of the energy distribution network, e.g. at one or more pilot node(s) representative of the voltage of a geographical area, typically the node(s) that is/are most likely to be subjected to departures from limit values or to fluctuations due to the intermittency of at least one system for generating renewable energy.

The energy storage units are connected on a common feed line, remote from the systems for generating renewable energy that generate the disturbances. The node(s) for connecting the systems for generating renewable energy (creating the disturbances), the node(s) for connecting the energy storage units (attenuating the disturbances), and the node(s) having voltage on which the regulation acts (where disturbances have the most impact, referred to as “pilot nodes” below) may all be different and may be positioned in various locations along the same outgoing line.

The invention also relates to a device for controlling an electrical energy storage unit for implementing the regulation method. With reference to FIG. 1, the regulation system 10 thus includes a central supervisor device 13 with which one or more control devices 12 of an electrical energy storage unit 11 are associated.