Voltage and frequency regulation at the common coupling point of industrial installations

Abstract

The industrial facility (10) connected to a power transmission grid (14) comprises a power distribution grid (16) connected to the power transmission grid (14) at a point of common coupling (12), at least one load (20) connected to the power distribution grid (16) via at least one power electronics block (22), where each power electronics block (22) is adapted to convert a current from the power distribution grid (16) into a current supplied to a respective load (20), each power electronics block (22) comprising a load responder component (34) adapted to determine a load demand (50) of the respective load (20), and at least one compensator (30) connected to the power distribution grid (16), where each compensator (30) is , adapted to stabilize a frequency and / or a voltage of a current in the power distribution network (16), each compensator (30) comprising a compensator responder component (32) adapted to receive a stabilization command (56) and apply the stabilization command (56) to a respective compensator (30), and a power controller (36) in data communication with the one or more load responder components (34) and the one or more compensator responder components (32), wherein the power controller (36) is adapted to receive load demands (50) from the one or more load responder components (34), determine stabilization commands (56) from the load demands (50), and send the stabilization commands (56) to the one or more compensator responder components (32).

Description

[Technical field]

[0001] The present invention relates to an industrial installation connected to a power grid. The present invention further relates to a method, a computer program, a computer readable medium and a controller for stabilizing the voltage and / or frequency at a common coupling point of the industrial installation with the power grid. [Background technology]

[0002] Variable energy source based grids rely on power electronics and when their contribution is high, such grids can be called Power Electronics Dominated Grids (PEDG). These grids are characterized by variable grid strength, low and variable inertia, and low short circuit power. For example, due to the weather dependency of some variable energy sources, the generation mix can change constantly.

[0003] Operations in these grids are subject to steady-state and transient stability challenges. In particular, grid-side and load-side transients can have serious effects due to rapid changes in active and reactive power, which can affect system voltage and frequency.

[0004] In contrast to conventional grids, voltage and frequency can be tightly coupled in PEDG, which can amplify the effects of transient events and lead to voltage and frequency stability problems.

[0005] Transient events include load dump of hydrogen generation units, load dump of electric arc furnaces, inrush current of high power converter transformers, instability due to arcing, symmetrical and asymmetrical faults on the load side, symmetrical and asymmetrical faults on the grid side, load shedding, etc. During the aforementioned transient events involving rapid changes in active and reactive power, the balance of supply and demand may be disturbed, leading to changes in voltage and frequency. In a conventional strong grid, changes in power components do not affect the system voltage and frequency. However, in PEDG, such scenarios may lead to disturbances in a wide range of industrial facilities and the grid. Summary of the Invention

[0006] The object of the present invention is to provide a control system and a control method that allows the operation of industrial facilities with strong and / or dynamically fluctuating loads on weak grids, in particular on grids supplied mainly by power electronic blocks supplying electric arc furnaces and renewable energy sources.

[0007] This object is achieved by the subject matter of the independent claims. Further illustrative embodiments are evident from the dependent claims and the following description.

[0008] A first aspect of the invention relates to an industrial facility connected to a power grid. The industrial facility may comprise electrical loads and / or be adapted to handle medium voltages, such as voltages above 6 kV, and / or high currents, such as above 100 A. The power electrical system and / or power electrical components of the industrial facility may be the power grid, power electronic blocks, such as inverters, rectifiers, and converters, passive and active filters, power loads, and power sources. Such power loads may be any electrical device that consumes power, such as motors, arc furnaces, etc. Such power sources may be any electrical device that provides power, such as battery storage systems, fuel cells, etc.

[0009] The power grid may be powered by renewable energy sources and / or variable power sources.

[0010] According to an embodiment of the invention, an industrial facility comprises an electrical grid connected to an electrical grid at a point of common coupling. The electrical grid may comprise one or more electrical cables for connecting the point of common coupling with the power electrical components of the industrial facility. The point of common coupling may be a point where the industrial facility interfaces with a public network or an energy service provider. The point of common coupling may be a high or medium voltage bus or a substation.

[0011] The power distribution network may connect loads and sources, as well as further power electrical components, with the power transmission network. On the one hand, the voltage and / or frequency of the power at the point of common coupling may fluctuate due to instabilities in the power transmission network. On the other hand, the voltage and / or frequency of the power at the point of common coupling may be fluctuating due to changes in the load demand of the industrial facility. With the systems and methods described herein, the voltage and / or frequency at the point of common coupling may be stabilized by following the control of the components of the industrial facility. For example, this may be beneficial when the industrial facility comprises a hydrogen-fed ore pelletizing plant with or without an electric arc furnace. Without the controls and systems as described herein, a weak and unstable grid may be destabilized by the operation of the pelletizing plant and / or the arc furnace, especially during transient events until the industrial facility or at least its components have to be reduced or switched off due to stability reasons.

[0012] According to an embodiment of the invention, an industrial facility comprises at least one load connected to a power grid via at least one power electronics block. The load may be any electric device consuming power. There may be one or more power electronics blocks per load. Each power electronics block is adapted to convert a current from the power grid into a current supplied to the respective load. The power electronics blocks may be of the converter type, naturally or forced commutated. They may also be of the direct or indirect converter type. For example, the power electronics block may be a rectifier, an inverter or a converter. The power electronics block may comprise power semiconductor switches, which may be controlled to provide the function of the power electronics block.

[0013] According to an embodiment of the present invention, each power electronics block comprises a load responder component adapted to satisfy and / or determine the load demand of the respective load. In general, the load responder component may be part of the controller of the power electronics block. The load responder component may be a module, such as a hardware or software module of the controller. The load responder determines the load demand of the load, such as the power needs of the load, which may refer to active power and / or reactive power, and / or power quality issues, such as harmonics, power factor, flicker, etc. This load demand may be sent via data communication lines to the central controller and / or the power controller for further processing.

[0014] The load responder component may determine further information, such as load state change information, e.g., that the load will increase and / or decrease its power demand in the future. The load responder component may also determine electrical measurement information, such as active and reactive power, at the input of the load, etc.

[0015] The load responder components may also receive power control information regarding the grid, such as that a load should reduce its power demand in the future. For example, an industrial facility may receive information that a power source may be disconnected from the grid and therefore the industrial facility must reduce its power demand. The power control information may be received over data communication lines from the central controller and / or the power controller.

[0016] According to an embodiment of the present invention, an industrial facility comprises at least one compensator connected to a power grid. Each compensator is adapted to stabilize the voltage and / or frequency in the power grid. A compensator may be any electric device that stabilizes the voltage and / or frequency of the power grid, and therefore of the transmission grid. It is noted that there may be loads that are also compensators, such as motors that may be operated as generators. A compensator may comprise a power source, a filter, a reactor, etc.

[0017] Different compensators may react at different rates to grid changes. Controllable electrical filters may react more quickly to load changes compared to energy storage systems and / or mechanical compensators. Faster inertial support may be provided by synchronous condensers compared to energy storage systems.

[0018] According to an embodiment of the present invention, each compensator comprises a compensator responder component adapted to receive a stabilization command and to apply the stabilization command to the respective compensator.

[0019] In general, the compensator responder component may be part of a controller of the compensator. The compensator responder component may be a module, such as a hardware or software module of the controller.

[0020] The stabilization command may be information related to stabilizing the voltage and / or frequency in the power grid. For example, it may comprise a command to increase or decrease the voltage or to provide active or reactive power support. The stabilization command may be executed by the respective compensator via control of the compensator responder components. The stabilization command may be received from the central controller and / or the power controller via data communication lines.

[0021] The compensator responder component may determine further information, such as compensator state change information, e.g., that a compensator, such as an energy store, is depleted. The compensator responder component may also determine electrical measurement information, such as active and reactive power, at the input of the compensator, etc. The electrical measurement information may be sent via data communication lines to the central controller and / or power controller for further processing.

[0022] According to an embodiment of the present invention, an industrial facility includes a power controller in data communication with one or more load responder components and one or more compensator responder components. All data received from the responder components, such as electrical measurement information, state change information, and / or load demand, can be processed by the power controller to control the voltage and / or frequency in the power grid. From the received data, the power controller determines stabilization commands and / or power control information and sends them to the respective responder components.

[0023] This may be done by adjusting set points for the loads and compensators, i.e. the stabilization command and / or power control information may comprise a set point for each load and / or compensator. The normal operation set points may be communicated from the power controller to all the loads and compensator responders. The power controller also receives measurements from the power grid. The power controller maintains models of the power grid, the loads and the compensators. If the voltage and / or frequency of the power grid leaves predefined limits, the power controller adjusts the set points so that the voltage and / or frequency stays within these limits. For this purpose the measurements and / or models may be used. According to an embodiment of the present invention, the power controller is adapted to receive load demands from one or more load responder components, determine stabilization commands from the load demands and send the stabilization commands to one or more compensator responder components.

[0024] Disturbances in power grids and industrial facilities can cause rapid changes in active and reactive power at the point of common coupling. These fast variations can cause voltage and frequency fluctuations that affect the process stability of the power grid and industrial facilities. To compensate for this, industrial facilities are equipped with a combination of controllable loads and compensators with respective load responder and compensator responder components, which are regulated by a power controller. This configuration performs a power balancing response by injecting and / or absorbing and / or providing inertial power to maintain the voltage and frequency within acceptable limits.

[0025] Inertial power can be related to frequency and real power. For example, when there is a disturbance, such as load shedding in a low inertia system, it can instantly affect the frequency due to the mismatch of real power. In a conventional grid, synchronous machines can provide automatic inertial support due to the kinetic energy stored in their rotors. This prevents the frequency from dropping instantly. In a distribution grid that relies on power electronics, the inertial support provided by synchronous machines may be missing. In this case, the inertial support from the load side can prevent the frequency from rising or falling instantly due to the disturbance. Synchronous condensers can provide automatic inertial support since they are directly connected to the distribution grid. As a further measure, other elements, such as hydrogen generation units, can be increased or decreased to provide frequency support by varying their real power consumption. A first response can be made through the synchronous condensers, and a second response can be made through the hydrogen generation units, which regulate their real power consumption.

[0026] According to an embodiment of the present invention, the power controller is connected with one or more load responder components and one or more compensator responder components via a data communication line adapted to transmit a data package within less than 25 μs. Such a data communication line may be referred to as a high-speed data communication line or a high-speed data communication line. The data communication may be as fast as the control system including the power controller and the responder components is adapted to react to changes in voltage and / or frequency so that direct control of the instantaneous voltage in the power distribution network is possible. In other words, the data communication may be as fast as the reaction can be realized faster than the period of the voltage in the power distribution network. In this way, the power controller can adjust the individual load responder components and compensator responder components by a high-speed point-to-point connection.

[0027] According to an embodiment of the present invention, the power controller is connected to one or more load responder components and one or more compensator responder components via a fiber optic data communication line. The fiber optic line, which may be made of glass, is adapted to provide high speed data communication as described above.

[0028] According to an embodiment of the present invention, one of the at least one compensator is a controlled electrical compensator comprising at least one of a resistor, an inductor, and a capacitor. An example for such a controlled compensator providing an active power compensator is a static power compensator.

[0029] In general, controlled compensators for reactive power include synchronous condensers, static var compensators, self-excited static var compensators, voltage sag compensators, integrated power flow controllers, inter-line power flow controllers, and the like.

[0030] According to an embodiment of the invention, one of the at least one compensator is a controlled mechanical compensator comprising a rotational inertia element such as a heavy drum driven by an electric motor / generator with or without a converter and / or power electronics block to control the flow of energy from the grid to the drum and vice versa. Such a device may be a synchronous condenser with or without a flywheel and / or may provide the rotational inertia.

[0031] According to an embodiment of the invention, one of the at least one compensator is a controlled energy storage system, such as a fuel cell, a battery bank, and / or a capacitor bank connected to a hydrogen tank. The energy storage system may also comprise a converter and / or a power electronics block for controlling the flow of energy from the grid to the energy storage element and vice versa.

[0032] According to an embodiment of the present invention, each of the one or more power electronic blocks comprises at least one of a rectifier and an inverter. In general, the power electronic blocks may be composed of power electronic components such as diodes, thyristors, and transistors controlled by a respective controller. The controller may provide a responder component.

[0033] According to an embodiment of the present invention, one of the at least one loads is an arc furnace, which may generate significant disturbances on the power grid and which may be compensated for by a control system as described herein.

[0034] According to an embodiment of the present invention, one of the at least one load comprises an electrolyzer bank and / or a fuel cell. The electrolyzer bank can be used to convert electrical energy into chemical energy stored in a hydrogen tank. The hydrogen can be converted back into electrical energy by the fuel cell. Such a load can also be considered as a compensator.

[0035] According to an embodiment of the invention, the industrial facility may also comprise a hydrogen-fed ore pelletizing plant, which is fed by hydrogen from a hydrogen tank. In this way, the energy surplus from the power grid may be compensated for by producing hydrogen, which can then be used to feed the ore pelletizing plant or to generate electricity via a fuel cell.

[0036] According to an embodiment of the present invention, the industrial facility further comprises an automation controller adapted to control the loads. The automation controller may be a PLC controller (Programmable Logic Controller). The automation controller may be used to coordinate process requirements with components such as loads controlling the process of the industrial facility. The automation controller acts as a superimposition controller. The automation controller typically includes and / or determines process information such as set points that are used to maintain the process and to perform emergency actions related to the process via the control components.

[0037] The automation controller is in data communication with the power controller, for example over a data communication line, with slower data communication than the data communication between the power controller and the responder component. For example, the automation controller may be connected to the power controller via a fieldbus. In this manner, the power controller cooperates with the automation controller and the utility to provide steady state support.

[0038] According to an embodiment of the present invention, the industrial facility further comprises a utility interface for receiving external data provided to the industrial facility. The utility interface may also be in data communication with the power controller. The utility interface may be used to receive information about the power grid, such as connecting and disconnecting power sources to and from the power grid, etc. Such information may also be used to adjust the loads and compensators.

[0039] A further aspect of the invention relates to a method for stabilizing the voltage and / or frequency at a point of common coupling of an industrial facility with a power grid, which may be performed by a power controller together with a transponder component and / or more generally by a compensator and a controller of a load.

[0040] According to an embodiment of the present invention, the method comprises receiving load demands from one or more load responder components. The load demands may be received via a data communication line connecting the power controller with the loads. The load demands may include information regarding the power beads of the respective loads.

[0041] According to an embodiment of the invention, the method comprises receiving state change information from one or more load responder components and / or one or more compensators. The load demands may be received via a data communication line connecting the power controller with the loads and the compensators. The state change information may, for example, describe that the corresponding load will increase and / or decrease its power demand in the future and / or that the corresponding compensator, such as an energy storage, is depleted.

[0042] According to an embodiment of the invention, the method comprises receiving electrical measurement information from one or more load responder components and / or one or more compensators. The electrical measurement information may be received via a data communication line connecting the power controller with the load and the compensator. The electrical measurement information may include voltage, current, active power, reactive power, etc. measured by the respective responder components and / or voltage, current, active power, reactive power, etc. derived from such measurements by the respective responder components.

[0043] According to an embodiment of the invention, the method comprises determining stabilization commands and / or power control information from load demand, state change information, and / or electrical measurement information using a power controller.

[0044] In general, the purpose of a power controller is to maintain the voltage and frequency within the electrical grid and / or at the point of common coupling within acceptable limits. These acceptable limits may be established in the power controller.

[0045] The power controller may determine compensation and / or responses of the load and compensator that achieve this objective. Depending on the compensation needed, e.g., encoded in the load demand, and based on the available reserve, e.g., encoded in the state change information from the compensator, set points may be determined that provide, for example, frequency support, active power, and / or reactive power compensation. The stabilization command and / or power control information may include such set points. If it is not possible to fully compensate the load demand of the load, power control information may be determined that, for example, informs the load to reduce its power consumption.

[0046] According to an embodiment of the invention, the method comprises sending stabilization commands to one or more compensator responder components and / or sending power control information to one or more load responder components, which may be sent via a high speed data communication link as described above.

[0047] According to an embodiment of the present invention, the method comprises controlling the load and / or the compensator based on the stabilization command and / or the power control information, Such control may be performed by a controller of the respective load and / or compensator.

[0048] Voltage and frequency may be considered as the main parameters of the control method executed by the power controller. Reliable operation of the industrial installation depends on their magnitude being within the permissible limits. During disturbances from the grid or one or more loads, especially in grids with low short circuit power and low inertia, due to changes in the active and reactive power, their values ​​may exceed the permissible limits. This may affect one or more loads and may lead to instabilities in the grid and / or the industrial installation, for example resulting from protection-related trips. During these critical situations, a fast controlled compensation of active and reactive power is provided by the method to ensure system stability. This control method compensates for the changes in the power components and prevents voltage and frequency changes that exceed the permissible limits. This allows the continuity of the process. In particular, load responders such as hydrogen generation units, including electrolyzer banks and storage and high-power fuel cells, as well as compensators such as battery storage systems, may be used for the controlled compensation of active and reactive power.

[0049] Further aspects of the invention relate to a computer program adapted to perform the methods as described above and below when executed by a processor, as well as a computer readable medium on which such a computer program is stored.

[0050] For example, the method may be performed by a control system of an industrial facility, which may be comprised of one or more controllers, each of which may comprise a memory and a processor. Such controllers may comprise a power controller, a load responder component, and / or a compensator responder component, all of which may be a controller of the industrial facility, or at least a portion or module of a controller.

[0051] The computer-readable medium may be a hard disk, a USB (Universal Serial Bus) storage device, a RAM (Random Access Memory), a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), or a flash memory. The computer-readable medium may also be a data communication network, such as the Internet, that allows downloading program code. In general, the computer-readable medium may be a non-transitory medium or a transitory medium.

[0052] Further aspects of the invention relate to a power controller adapted to perform the methods as described above and below. The power controller may be and / or may comprise one or more controller components. Each controller component may comprise a memory and a processor. Some or all of the power components may be provided by modules of a controller of an industrial facility. The controller components of the power controller may be interconnected by high speed data communication lines and / or optical fiber based data communication lines.

[0053] It will be appreciated that features of the power controller as described above and below may be features of the industrial installation, the method, the computer program, and the computer readable medium as described above and below, and vice versa.

[0054] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0055] The subject matter of the invention is explained in more detail in the following description with reference to exemplary embodiments that are illustrated in the attached figures. [Brief description of the drawings]

[0056] [Figure 1] 1 illustrates diagrammatically an industrial facility according to an embodiment of the present invention; [Diagram 2]1 illustrates a flow diagram of a method for stabilizing voltage and / or frequency at a point of common coupling in an industrial facility. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] The reference signs used in the figures and their meanings are listed in summary form in the list of reference signs. As a rule, identical parts are provided with the same reference signs in the figures.

[0058] 1 shows an industrial facility 10 connected to an electrical grid 14 via a point of common coupling 12. The electrical grid 14 may be a grid powered by renewable energy sources and / or variable power sources.

[0059] The industrial facility 10 includes an electrical grid 16 made up of electrical transmission lines 18. The electrical grid 16 connects with the electrical transmission grid 14 at a point of common coupling 12. The electrical grid 16 may include one or more electrical transmission lines 18, such as electrical cables, for connecting the point of common coupling 12 with the power electrical components of the industrial facility 10. The connection may be via switchgear or circuit breakers to busbars of the electrical grid 16.

[0060] The industrial facility 10 further comprises loads 20, 20a, 20b connected to the power grid 16 via a power electronics block 22. In general, the loads can be any electric device that consumes power. The load 20a is an arc furnace. The arc furnace 20a can generate large disturbances in the power grid 16 that can be compensated for by the method and control system as described herein.

[0061] The load 20b comprises an electrolyser bank and / or a fuel cell connected via a pipeline 24 to a hydrogen tank 26. The electrolyser bank may be used to convert electrical energy into chemical energy that is stored in the hydrogen tank 26. The chemical energy of the hydrogen may be converted back into electrical energy by the fuel cell.

[0062] The industrial facility 10 may also include a hydrogen-fed ore pelletizing plant 28 , which is fed by hydrogen from a hydrogen tank 26 via a further pipeline 24 , for example.

[0063] Each power electronics block 22 is connected to a respective load 20 via the power transmission line 18. Each power electronics block 22 is adapted to convert a current from the power grid 16 into a current supplied to the respective load 20. The power electronics blocks 22 may comprise rectifiers, inverters, and / or converters. In general, the power electronics blocks 22 may be composed of power electronic components such as diodes, thyristors, and transistors, which are controlled by respective controllers. The power electronics blocks 22 may comprise power semiconductor switches, which may be controlled to provide the functions of the power electronics blocks 22.

[0064] Furthermore, the industrial facility 10 comprises compensators 30 connected to the power grid 16. Each compensator 30 is adapted to stabilize the voltage and / or frequency in the power grid 16. In general, the compensators 30 may be any electric device that stabilizes the voltage and / or frequency of the power grid 16 and thus of the power grid 14. It is noted that there may be loads 20, such as load 20b, that may also be considered as compensators 30.

[0065] The compensator 30a is a controlled energy storage system, such as a capacitor bank or a battery bank. The energy storage system 30a may also include converters and / or power electronics blocks for controlling the flow of energy from the grid 16 to the energy storage elements and vice versa.

[0066] Compensator 30b is a controlled mechanical compensator that includes a rotational inertia element such as a heavy drum driven by an electric motor / generator with a converter and / or power electronics block to control the flow of energy to the drum and vice versa from grid 16. Compensator 30b may also be a synchronous condenser with or without a flywheel and / or provide the rotational inertia.

[0067] The compensator 30c is a controlled electrical compensator comprising at least one of a resistor, an inductor, and a capacitor. An example for such a controlled compensator 30c providing an active power compensator is a static watts compensator.

[0068] In general, the controlled compensator 30 for reactive power includes a synchronous condenser, a static Var compensator, a static synchronous compensator, a dynamic voltage restorer, a unified power flow controller, a line-to-line power flow controller, and the like.

[0069] Each of the power electronics block 22 and the compensator 30 comprises a responder component 32, 34. The responder component 32, 34 may be part of a controller of the respective power electronics block 22 or the respective compensator 30. The responder component 32, 34 may be a module, such as a hardware or software module of such a controller. The compensator 30 comprises a compensator responder component 32. The power electronics block 22 comprises a load responder component 34.

[0070] The responder components 32, 34 are in data communication with a power controller 36 of the industrial facility 10. The power controller 36 is responsible for controlling the real and reactive power provided to the grid 16 by the loads 20 and the compensator 30 and / or for keeping the voltage and frequency of the grid 16 within limits.

[0071] The power controller 36 is connected to the transponders 32, 34 via a data communication line 38 adapted to transmit data packages within less than 25 μs. For example, the protocol used may be a power link. The data communication line 38 may be an optical fiber data communication line. In this way, the data communication may also not be disturbed by electromagnetic fields generated in the industrial facility by the power electronics block 22 or the like.

[0072] The industrial facility 10 further comprises an automation controller 40 adapted to control the process performed by the loads 20. The automation controller 40 is in data communication with the power controller 36 via a data communication line 42 at a slower data communication rate than the data communication via the communication line 38. For example, the automation controller 40 may be connected to the power controller 36 via a fieldbus.

[0073] Furthermore, the industrial facility 10 includes a utility interface 44 for receiving external data provided to the industrial facility 10. The utility interface 44 also has data communication with the power controller 36. This data communication may be performed via the data communication line 38 as described above. The utility interface 44 may be used to receive information about the power grid, such as the connection and disconnection of power sources to and from the power grid, etc. Such information may also be used by the power controller 36 to adjust the loads 20 and the compensator 30. The utility interface 44 may also have data communication with the automation controller 40, which may be performed via the data communication line 42, for example via a fieldbus, as described above.

[0074] 2 shows a flow diagram of a method for stabilizing the voltage and / or frequency at the point of common coupling 12 with the power grid 14 of the industrial facility 10. The method is performed by a power controller 36 in conjunction with the responder components 32, 34 and / or more generally by the controllers of the load 20 and compensator 30.

[0075] In step S10, the load demand 50 is received from the load responder component 34. The load demand 50 may include information regarding the power needs of each load 20.

[0076] In step S12, state change information 52 is received from the load responder component 34 and / or from the compensator responder component 32. The state change information 52 may describe, for example, that the corresponding load 20 will increase and / or decrease its power demand in the future, and / or that it has been tripped due to protection-related reasons, and / or that the corresponding compensator 30, such as an energy store, is depleted.

[0077] In step S14, electrical measurement information 54 is received from the load responder component 34 and / or from the compensator responder component 32. The electrical measurement information 54 may include voltages, currents, active powers, reactive powers, etc. measured by the respective responder components and / or voltages, currents, active powers, reactive powers, etc. derived from such measurements by the respective responder components 32, 34.

[0078] The load demand 50 , state change information 52 , and electrical measurement information 54 are transmitted to the power controller 36 via data communication lines 38 .

[0079] In step S16, the power controller 36 determines stabilization commands 56 and / or power control information 58 from the load demand 50, state change information 52, and / or electrical measurement information 54. In general, the objective of the power controller 36 is to maintain the voltage and frequency within the electrical grid 16 and / or at the point of common coupling 12 within acceptable limits. These acceptable limits may be established in the power controller 36.

[0080] The power controller 36 determines the compensation and / or reaction of the load 20 and compensator 30 that achieves this objective. Depending on the compensation required, such as encoded in the load demand 50, and based on the available reserve, such as encoded in the state change information 52 from the compensator 30, set points may be determined that provide, for example, inertial response, active power, and / or reactive power compensation. The inertial response from a synchronous condenser may be automatic due to its rotating mass. The inertial response from other compensators, such as an electrolyzer or battery storage system, may have to be controlled by a set point. The stabilization command 56 and / or the power control information 58 may include such set points. If it is not possible to fully compensate the load demand 50 of the load 20, the power control information 58 may be determined that notifies the load 20 to reduce its power consumption.

[0081] The stabilization command 56 may be information regarding stabilizing the voltage and / or frequency in the power grid 16. For example, it may comprise a command to increase or decrease the voltage or to provide active or reactive power support. The stabilization command 56 may be executed by the respective compensator 30 via the control of the compensator responder component 32. In step S18, the power controller 36 sends the stabilization command 56 to the compensator responder component 32 and sends the power control information 58 to the load responder component 34. This information is sent via the data communication line 38.

[0082] In step S20, the compensator responder components 32 apply stabilization commands 56 to their respective compensators 30. The load responder components 34 apply power control information 58 to the power electronics block 22 and the load 20.

[0083] The power electronics block 22, the load 20, and / or the compensator 30 are controlled based on the stabilization commands 56 and / or the power control information 58. Such control may be performed by a controller of the respective load and / or compensator.

[0084] During normal operating conditions, the automation controller 40 may communicate set points to the individual load responder components 34 via the power controller 36. Based on information about the grid 16 from exchanging information with the load and responder components 32, 34 and measurements, the power controller 36 further adjusts the set points and / or transmits set points to the load and responder components 32, 34 to maintain the voltage and frequency in the grid 16 within acceptable limits. The automation controller 40 may also provide information about load forecasts or weather-dependent generation forecasts to the power controller 36, which may be used to further adjust the set points for the loads 20 and compensators 30.

[0085] During an unforeseen event, such as load shedding, the utility interface 44 may communicate directly with the power controller 36, which may control the loads 20 by overriding set points from the automation controller 40 and / or send set points directly to the load and responder components 32, 34. In another example, when there is a load shedding due to process or electrical system related reasons, the power controller 36 receives this information from the respective load responder components 34 or interprets it based on direct measurements.

[0086] Based on the available information, the power controller 36 can send stabilization commands 56 to the compensator responder component 32, taking into account the amount of compensation required to maintain the voltage and frequency. When the compensation reserve is reached, the power controller 36 can send power control information 58 to the loads 20, such as hydrogen units, to increase or decrease their production or receive support from a battery storage system. Through this combined action, the power controller 36 can bring the voltage and frequency within allowed limits to allow for process continuity. In a further example, when there is a grid fault, voltage support to the grid 16 can be initiated by the power controller 36 by modifying the set points for the compensator 30 and the loads 20.

[0087] In this way, voltage and frequency stability at the point of common coupling 12 can be achieved by using a controlled load 20 and compensator 30. Depending on the scenario, i.e. voltage or frequency support or both, this combination provides inertial response, reactive power support and / or real power support. Inertial support can be provided automatically with a synchronous condenser in combination with a flywheel. Controlled inertial support can be provided by using a hydrogen generation unit and / or a battery storage system.

[0088] While the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered as illustrative or illustrative and not restrictive, and the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or controller or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. [Explanation of symbols]

[0089] 10 Industrial Facilities 12 Common connection point 14 Power grid 16 Electricity distribution network 18 Power Lines 20 Load 20a AC or DC arc furnace 20b Electrolyser bank and / or fuel cell 22 Power Electronics Block 24 Pipeline 26 Hydrogen Tank 28 Ore Pelletizing Plant 30 Compensator 30a Energy Storage System 30b mechanical compensator 30c electrical compensator 32 Compensator Responder Components 34 Load Responder Components 36 Power Controller 38 Data communication lines 40 Automation Controller 42 Data communication lines 44 Utility Interfaces 50 load demand 52 Status change information 54 Electrical Measurement Information 56 Stabilization Command 58 Power Control Information

Claims

1. An industrial facility (10) connected to a power grid (14), the industrial facility (10) comprising: a power distribution network (16) connected to the power transmission network (14) at a point of common coupling (12); at least one load (20) connected to the power grid (16) via at least one power electronics block (22), where each power electronics block (22) is adapted to convert a current from the power grid (16) into a current supplied to a respective load (20), and where each power electronics block (22) comprises a load responder component (34) adapted to determine a load demand (50) of the respective load (20); at least one compensator (30) connected to the power distribution network (16), where each compensator (30) is adapted to stabilize a frequency and / or a voltage of a current in the power distribution network (16), each compensator (30) comprising a compensator responder component (32) adapted to receive a stabilization command (56) and apply the stabilization command (56) to the respective compensator (30); a power controller (36) in data communication with one or more of the load responder components (34) and one or more of the compensator responder components (32), wherein the power controller (36) is adapted to receive load demands (50) from the one or more of the load responder components (34), determine stabilization commands (56) from the load demands (50), and send the stabilization commands (56) to the one or more of the compensator responder components (32). An industrial facility (10).

2. 2. The industrial facility (10) of claim 1, wherein the power controller (36) is connected to one or more of the load responder components (34) and one or more of the compensator responder components (32) via a data communication line (38) adapted to transmit data packages within less than 25 μs.

3. The industrial facility (10) of claim 1 or 2, wherein the power controller (36) is connected to one or more of the load responder components (34) and one or more of the compensator responder components (32) via an optical fiber data communication line (38).

4. The industrial installation (10) according to any one of claims 1 to 3, wherein one of the at least one compensator (30) is a controlled electrical compensator (30c) comprising at least one of a resistor, an inductor, and a capacitor.

5. The industrial installation (10) according to any one of claims 1 to 4, wherein one of the at least one compensator (30) is a controlled mechanical compensator (30b) comprising a rotational inertia element.

6. The industrial installation (10) according to any one of claims 1 to 5, wherein one of the at least one compensator (30) is a controlled energy storage system (30a).

7. The industrial installation (10) according to any one of claims 1 to 6, wherein the power electronics block (22) comprises at least one of a rectifier and an inverter.

8. The industrial installation (10) according to any one of the preceding claims, wherein one of the at least one load (20a) is an electric arc furnace.

9. The industrial installation (10) according to any one of the preceding claims, wherein one of the at least one load (20b) comprises an electrolyser bank and / or a fuel cell.

10. The industrial facility (10) of any one of claims 1 to 9, further comprising an automation controller (40) adapted to control the loads (20), the automation controller (40) in data communication with the power controller (36).

11. The industrial facility (10) of any one of claims 1 to 10, further comprising a utility interface (44) for receiving external data provided to the industrial facility (10), the utility interface (44) being in data communication with the power controller (36).

12. A method for stabilizing the voltage and / or frequency at a point of common coupling (12) with a power grid (14) of an industrial installation (10) according to any one of the preceding claims, said method comprising the steps of: receiving load demands (50) from one or more of the load responder components (34) using the power controller (36); determining a stabilization command (56) from the load demand (50) using the power controller (36); sending the stabilization command (56) to one or more of the compensator responder components (32).

13. A computer program adapted to perform the method according to claim 12 when executed by a processor.

14. A computer readable medium having stored thereon the computer program of claim 13.

15. A power controller (36) adapted to perform the method of claim 12.

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