Hitachi Energy Patente

There is provided mechanisms for differential protection of a transmission line of a transmission system. A method comprises obtaining a restraining current and a differential current from the transmission line. The method comprises determining a compensation current for the differential current. The method comprises providing the differential current as compensated for by the compensation current and the restraining current to a differential protection arrangement for making a trip decision. The method comprises detecting an internal fault for the transmission system. The method comprises, as a result thereof, providing the differential current without being compensated for by the compensation current and the restraining current to the differential protection arrangement for making the trip decision.

The invention relates to a method for determining a faulted phase on a power transmission line, the method comprising obtaining a voltage signal and a current signal of the transmission line, determining a change in the magnitude of the apparent power, ΔS, for each phase based on the voltage and current signal, determining a fault voltage angle, and determining a faulted phase based on ΔS and the fault voltage angle.

The present disclosure relates to a method for optimizing power generation in a power network using Benders decomposition, the method comprising performing one or more iterations of the following steps: a) determining a solution for each master problem, MPi, of a plurality of master problems, wherein each MPi is based on a different slack weight, Wi, of a plurality of slack weights; b) selecting a slack weight wi based on a first predetermined condition; c) selecting the solution for the MPi that corresponds to the selected wi as an input for one or more subproblems; d) determining one or more solutions for the one or more subproblems; and e) when a second predetermined condition is met, inputting the determined one or more solutions of the one or more subproblems of step d) into each MPi of step a) of the subsequent iteration.

In one embodiment, the electric system (1) comprises a static electric induction device (2) and a corrosion-sensitive coating (31), wherein- the electric system (1) further comprises a protective coating (4) to protect a component (21, 22, 23, 24, 25) of the electric system (1) from an exterior (A) of the electric system (1),- the corrosion-sensitive coating (31) comprises a luminescent material (30) and is applied on a substrate (34) of the component so that the corrosion-sensitive coating (31) is located between the substrate (34) and the protective coating (4), and- the luminescent material (30) is configured to emit luminescence (L) upon activation by at least one of a change of a pH value or occurrence of metal ions caused by corrosion of the substrate (34) so that the corrosion-sensitive coating (31) is configured to provide information about a corrosion state of the component.

Embodiments of present disclosure provide power conversion system (100) and method (200) for converting power. Power conversion system (100) comprising energy storage elements (102), first converter (103) connected to grid (104) to provide bi-directional flow of power between first converter (103) and grid (104). Second converter (107) connected to energy storage elements (102) at one end and other end connected to electric machine (106). Output of second converter (107) is supplied as input to electric machine (106). Controller (108) controls at least one of: current flowing from grid (104) to energy storage elements (102) and corresponding voltage between grid (104) and energy storage elements (102), current flowing from energy storage elements (102) to grid (104) via first converter (103) and corresponding voltage between energy storage elements (102) and grid (104), and current flowing from energy storage elements (102) to control operation of electric machine (106) via second converter (107).

The invention relates to a gas-insulated electrical application (1), particularly gas-insulated switchgear or gas-insulated line, comprisingtwo flanges (10, 12) connected to each other in a connection region (14),an insulator (30) with an annular base (32) arranged in the connection region (14) to be held by the two flanges (10, 12), anda sealing ring (50) arranged with a first side (51) in a groove (34) of the annular base (32) and configured for sealing with a second side (52) against one of the two flanges (10, 12), whereinthe sealing ring (50) comprises a recess (54) on at least one of the first side (51) and the second side (52), and/orthe groove (34) comprises stepped edges (36, 38) of which a radially outwards stepped edge (38) is wider in a radial direction than a radially inwards stepped edge (36).

The present disclosure relates to a charging management device for electric vehicles comprising at least one processor configured to obtain a predetermined state of charge, SoC, of a battery of the electric vehicle; determine a power consumption for reaching the predetermined SoC; determine a power consumption for preconditioning of the electric vehicle; and assign a power reserve of at least one electric charger to the electric vehicle based on the determined total power consumption. The disclosure further relates to a corresponding method, system, storage device and computer program.

The present disclosure relates to a charging management device for electric vehicles comprising at least one processor configured to obtain a predetermined state of charge, SoC, of a battery of the electric vehicle, obtain a target time for reaching the predetermined SoC, determine a power consumption for reaching the predetermined SoC within the target time and assign a sequence of chargers of a plurality of chargers based on the predetermined SoC, the target time, and the determined power consumption. The present disclosure further encompasses a corresponding method and system.

A transformer core (1) comprising a plurality of legs (2) is specified, wherein- the legs (2) comprise a plurality of core sheets (21),- a flitch plate (3) is attached to the core sheets (21) of one of the legs (2), the flitch plate (3) being configured to mechanically stabilize the leg (2),- the flitch plate (3) comprises a plurality of sheets (31), and- adjacent sheets (31) of the flitch plate (3) are bonded to one another via an adhesive layer (32).Further, a transformer (10) and a method of producing a transformer core (1) are specified.

In one embodiment, the method is for laminating a core part (20) of a static electric induction device (1) and comprises:A) providing a first stack (41) of sheets (25) for the core part (20),B) assembling a second stack (42) of the sheets (25), the sheets (25) are taken one by one from the first stack (41), the sheets (25) are oriented between 30° and 70° relative to a vertical direction (V),C) forming a third stack (43) by taking the whole second stack (42), the sheets (25) are oriented at most 25° relative to the vertical direction (V), andD) taking the third stack (43) and incorporating it into the core part (20), the sheets (25) are oriented at most 5° relative to the vertical direction (V) in the core part (20), so that the core part (20) is laminated of the sheets (25).

The present disclosure relates to a method of controlling a power supporting system (1) for a power transmission or distribution system, said power supporting system (1) being controllable to: a first power supporting mode (S8) in which said power supporting system (1) is capable of providing active power support and reactive power support, said active power support being provided by means of an energy storage system (20), ESS, having been charged to an energized state, and said reactive power support being provided by means of a voltage source converter (10), VSC, and a second power supporting mode (S5) in which said power supporting system (1) is capable of providing reactive power support by means of said VSC (10), and in which said ESS (10) is in a de-energized state, the method comprising: determining if said power supporting system (1) is operating with normal switching behavior or with emergent switching behavior; during normal switching behavior, controlling the power supporting system (1) so that, when switching mode from said first power supporting mode (S8) to said second power supporting mode (S5), said ESS (20) is discharged by means of operating at least one switch of the VSC (10), and in response to a detection of emergent switching behavior, controlling the power supporting system (1) so that, when switching mode from said first power supporting mode (S8) to said second power supporting mode (S5), said ESS (20) is discharged by means of a protection circuit (40) configured to consume energy of the ESS (20). A control device (30) and a power supporting system (1) is also disclosed.

In one embodiment, the electric system (1) comprises a static electric induction device (2) and an electric resistance, ER, sensor (3), wherein - the electric system (1) further comprises a protective coating (4) to protect a component (21, 22, 23, 24, 25) of the electric system (1) from an exterior (A) of the electric system (1), - the ER sensor (3) comprises a measurement conductor track (31) and a reference conductor track (32), - the protective coating (4) and the ER sensor (3) are configured to be in direct contact with the exterior (A), - the reference conductor track (32) is permanently shielded from the exterior (A), - the measurement conductor track (31) is less shielded from the exterior (A) than the reference conductor track (32), and - the ER sensor (3) is configured to provide information about a corrosion state of the protective coating (4).

The invention relates to a switchgear (1) for breaking an electrical connection, comprising a first contact structure (10) with a first base (12) and a first contact member (14); a second contact structure (20) with a second base (22) and a second contact member (24) and corresponding to the first contact structure (10); a spring accumulator (30) configured for resiliently mounting the first (14) or the second (24) contact member on the respective first (12) or second (22) base; a drive system (40) configured for at least partially moving the first (14) and the second (24) contact members relative to one another along a switching axis (2) in order to break the electrical connection to ground (GND); and a locking means (50) configured for locking the first (14) and the second (24) contact members along the switching axis (2) in a releasable manner.

The invention relates to a circuit-breaker (1), comprisinga gas compression arrangement (4) configured for compressing a quenching gas to be contained therein and which quenching gas is free of sulphur hexafluoride;a first contact (20) and a second contact (30) movable relative to one another along a switching axis (2);a nozzle (40) providing an inflow channel (IN) connecting the gas compression arrangement (4) to an arc zone (3), the inflow channel (IN) constituting a minimal inflow area to be passed by the quenching gas, the nozzle (40) radially restricting the arc zone (3) between the first contact (20) and the second contact (30);wherein, for the quenching gas to exit the arc zone (3), the circuit-breaker (1) provides at least one outlet (OUT1, OUT2) constituting a minimal outflow area, andthe minimal inflow area divided by the minimal outflow area defines an inflow-outflow-ratio being at least 0.5.

A contact structure (10) for an on-load tap changer (100) is provided, wherein the contact structure (10) is formed in one-piece. The contact structure (10) comprises a dense part (4) and at least one hollow part (2, 2A, 2B) arranged next to the dense part (4). The contact structure (10) comprises at least one shielding area (3, 3A, 3B), wherein at least one shielding area (3, 3A, 3B) is arranged next to the at least one hollow part (2, 2A, 2B). Moreover, an on-load tap changer (100) comprising at least one contact structure (10) and a method for producing a contact structure (10) are provided.

An electric circuit (1) comprising a power thyristor (2) device (2) is specified, wherein - a gate (21) of the power thyristor device (2) is connected to an internal reference (10) of the electric circuit (1) via a first switch (31); and - a cathode (22) of the power thyristor device (2) is connected to the internal reference (10) of the electric circuit (1) via a second switch (32). Further, a method of operating an electric circuit (1) is specified.

There is disclosed herein a method for operating a converter unit (10) of a STATCOM (4), configured to be connected to a power grid (2) connected to at least one voltage flicker source (6). The method comprises determining (110) a grid-forming reference based on an active power (110a) and/or an energy level (110b) of the STATCOM, determining (120) a grid-following reference based on a reactive power (120a) and/or a voltage (120b) of the power grid. The method further comprises obtaining (130) a first current reference value by subjecting (125) the grid-forming reference and the grid-following reference to a mathematical operation and subjecting the result thereof to a virtual admittance, determining (140) a second current reference value based on a current at the voltage flicker source, and obtaining (150) a current reference, for controlling the converter unit, based on the first current reference value and the second current reference value. There are also disclosed herein a control unit and a power grid system.

The present disclosure relates to a method for determining a status of a power grid, wherein the power grid comprises a plurality of branches each connected between two buses. The method comprises obtaining current measurements of at least one of the plurality of branches, obtaining a grid model, the model comprising the plurality of branches and buses, estimating, using the grid model and the current measurements, a voltage value of at least one of the plurality of buses, determining, using the voltage values and current measurements, current estimates of remaining branches of the plurality of branches having an unknown status and determining the status of the remaining branches of the plurality of branches based on the estimated currents.

The present disclosure relates to a method for determining a status of a power grid, wherein the power grid comprises a plurality of branches each connected between two buses. The method comprises obtaining current measurements of at least one of the plurality of branches, obtaining a grid model, the model comprising the plurality of branches and buses, estimating, using the grid model and the current measurements, a voltage value of at least one of the plurality of buses, obtaining, from a controller, at least one parameter of at least one of remaining branches of the plurality of branches, determining, based on the at least one parameter and current measurements of the at least one of the plurality of branches, currents of the remaining branches of the plurality of branches and determining or correcting the status of the remaining branches of the plurality of branches based on the estimated currents.

Embodiments of present disclosure provide converter system and method connecting first AC system to second AC system. First converter comprises first phase legs arranged by cascading first sub-converters between two DC lines connected to terminals of DC links. Connections of first sub-converters form AC connection terminals and first phase legs are arranged as first phase-arms in sub-converters. Second converter comprises second phase legs arranged by cascading sub-converters, between two DC lines connected to terminals of DC links. Connections of sub-converters form AC connection terminals and second phase legs are arranged second phase-arms in the cascaded sub-converters. First converter or second converter operates rectifier or converter. First phase legs or second phase legs comprises bipolar cell in each phase to control potential difference between DC links. Potential difference between DC links and output voltage of the inverter is changed by value of voltage blocked by bipolar cell.

The disclosure provides a method for determining a faulted section in a collector grid feeder comprising a plurality of sections, the method comprising obtaining a voltage at a collector bus at a local end of the feeder (8), obtaining a first current signal through the feeder and a second current signal through the feeder, determining a first fault direction value, based on the first current signal and a derivative of the first current signal, and determining a first fault direction based on the first fault direction value, and determining a second fault direction value based on the second current signal and a derivative of the second current signal and determining a second fault direction based on the second fault direction value, and determining a faulted section based on a comparison between the first fault direction and the second fault direction.

The disclosure provides a method for determining a fault location in a faulted section in a collector grid feeder, the method comprising obtaining a first voltage and a first current signal at a local end of the section, obtaining a second current signal at a remote node of the section; and determining a fault location based on the first voltage signal, the first current signal, and the second current signal.

Green-hydrogen plants, connected to weak power grids in geographically remote areas, are prone to frequency fluctuations and instability due to the variability in renewable-energy generation. Disclosed embodiments provide balancing control within the green-hydrogen plant to provide both fast frequency response during contingency conditions and automatic frequency regulation during normal conditions. The fast frequency response may be centralized or distributed, and may combine frequency droop response with fast frequency response or synthetic inertial response. The automatic frequency regulation may determine optimal allocations of a total net power adjustment, which compensates a balance control error in the system, to a plurality of different power resources of the green-hydrogen plant. These power resources may comprise electrolyzer plant(s), renewable energy source(s), and/or energy storage system(s).

There is provided a conservator tank (100) for a transformer tank (200) comprising a housing (10) with a magnetic inner surface (11), which houses an insulation oil (20) inside the housing (10). The conservator tank (100) further comprises a rubber bag (30) with an upper part (31) facing away from the insulation oil (20), and a lower part (32) opposite the upper part (31) facing towards the insulation oil (20). The rubber bag (30) further has a first peripheral side (33) arranged between the upper part (31) and the lower part (32) and a second peripheral side (34) arranged between the upper part (31) and the lower part (32) opposite the first peripheral side (33). The rubber bag (30) is configured to inflate or deflate inside the housing (10), such that the lower part (32) contacts and immerses into an oil surface (21) of the insulation oil (20). The rubber bag (30) has a rubber layer (35) with a first magnetic fastening element (36) arranged on the upper part (31), wherein the first magnetic fastening element (36) is configured to be attached to the magnetic inner surface (11) in a mounted state of the rubber bag (30).

The invention relates to an insulator assembly (12) for a high or medium voltage device comprising:an insulator (16), the insulator (16) being attached to an enclosure (10) of the high or medium voltage device at an outer rim of the insulator (16), the insulator (16) further being configured to accommodate a conductor (18) within a device volume (14) enclosed by the enclosure (10), anda particle shield (22) arranged within the device volume (14), the particle shield (22) being connected to the enclosure (10), and wherein the particle shield (22) at least in part extends parallel to an axial direction (24) of the conductor (18) accommodated by the insulator (16) and circumferentially along the connection of the insulator (16) to the enclosure (10).Furthermore, the invention relates to high or medium voltage device comprising the above insulator assembly (12).

The present disclosure relates to a method for determining a fault section in a series-compensated transmission line, the method comprising: obtaining impedance parameters of the transmission line; obtaining a first voltage and a first current at a first bus; obtaining a second voltage and a second current at a second bus; obtaining a current through an series compensator in a direction towards the first bus, wherein the series compensator is arranged between the first bus and the second bus; and determining a fault section based on: the impedance parameters, the first voltage and the first current, the second voltage and the second current, and the current through the series compensator.

A module (10) is provided which comprises a first module part (1) comprising a first electrical conductor (11), first foils (12) and first isolating structures (13) alternated with the first foils (12). The module (10) further comprises a second module part (2) comprising a second electrical conductor (21), second foils (22) and second isolating structures (23) alternated with the second foils (22). The module (10) further comprises a joint region (3) which includes a conductor connector (31), connecting structures (32) and an insulation material (33). The first module part (1) and the second module part (2) are joined together in the joint region (3). The conductor connector (31) mechanically and electrically connects the first electrical conductor (11) to the second electrical conductor (21). Each one of the connecting structures (32) electrically connects one of first foils (12) to one of the second foils (12). The joint region (3) is filled with the insulation material (33) for electrically isolating at least the conductor connector (31) and the connecting structures (32) from each other. Moreover, a method for producing such a module (10) is provided.

A load cell (1) for measuring forces in a transformer, comprises a measuring portion (4) and a sensor (5) for measuring a deformation of the measuring portion (4), and comprising a load cell housing (2), wherein the measuring portion (4) and the sensor (5) is embedded in the load cell housing (2), wherein the load cell housing (2) comprises at least one supporting structure (13) for limiting a force exerted on the deformable portion (4).

The present disclosure relates to a method of operating a system (10), the system (10) including a first device (12) and a second device (14), the second device (14) being configured to act as a backup device to the first device (12), the first device (12) and the second device (14) each having a service-oriented architecture, SOA. The method includes evaluating, by the system (10), a readiness of the second device (14) to take over operation from the first device (12) based on data which is gathered and/or calculated, while the system (10) is in operation; generating, by the system (10), a readiness signal based on evaluating the readiness of the second device (14) to take over operation from the first device (12); determining, by the system (10), whether to cause and/or allow the second device (14) to take over operation from the first device (12) based on the readiness signal. The present disclosure also relates to an apparatus and a system (10).

The present disclosure relates to a method of operating a system (10), the system (10) including a first device (12) and a second device (14), the first device (12) and the second device (14) each having a service-oriented architecture, SOA. The method includes operating the first device (12), wherein the second device (14) is configured to act as a backup device to the first device (12); at least partially reconfiguring the second device (14), while the first device (12) is being operated; causing the second device (14) to take over operation of the first device (12) after at least partially reconfiguring the second device (14) has been completed.

To perform a battery degradation assessment, a data processing system (20) obtains battery-related data (24) for a battery. The battery-related data (24) comprises time information for several charging and/or discharging operations. The data processing system (20) is operative to determine, based on the time information, a duration for which an operation was carried out, the operation being a charging operation (or a discharging operation. The data processing system (20) is operative to evaluate a cycling aging model (33) to determine a degradation indicator. The cycling aging model (33) comprises a power function of the duration.

A method for edge-cloud computing performed in a system comprising a number of bay clients (23a1, 23b1, 23c1), each bay client belonging to a bay, a plurality of edge devices (22a, 22b, 22c), with thereto belonging edge brokers (22a1, 22b1, 22c1), and a cloud 21. The method comprises a bay client (23a1) publishing primary equipment data to an edge broker (22a1), and the edge broker (22a1) publishing, or making available, the equipment data, in the cloud (21). A primary edge device (22a), from the plurality of edge devices (22a, 22b, 22c), is designated to each bay, and where the edge brokers (22a1, 22b1, 22c1) are bridged to each other, thus making any sensor data published on one edge broker (22a1) available on any other edge broker (22b1, 22c1).

The present disclosure relates to a fault detection method for a power transmission line (101) in an alternating current, AC, power transmission system (100). The method comprises:- measuring, at a local position of the power transmission line, measured local voltage phasors and measured local current phasors;- obtaining transmission properties for the power transmission line from the local position to a remote position at a distance from the local position and for associated devices, wherein the transmission properties comprise series parameters, shunt parameters, and the distance from the local position to the remote position;- estimating, for the remote position, estimated remote voltage phasors and estimated remote current phasors on basis of the measured local voltage phasors, the measured local current phasors, and the transmission properties;- receiving, via a communication link (115), data relating to remote phase currents and determining measured remote current phasors;- determining whether a fault has occurred or not on basis of at least one of a combination of the estimated and measured remote current phasors and a combination of the estimated and measured remote voltage phasors; and- determining whether a fault is a true fault or a false fault, including:o comparing a first phase angle and a first magnitude of an estimated remote positive sequence current phasor with a second phase angle and a second magnitude of a measured remote positive sequence current phasor;o determining, on basis of the comparison, whether there is a significant channel asymmetry on the communication link; ando determining that the fault is a false fault if there is a significant channel asymmetry.

An acoustic panel (1) for an electric appliance (2) with a tank (21) is specified, wherein - the acoustic panel (1) comprises an inner plate (11) facing the tank (21) and an outer plate (22) facing away from the tank (21), - a resonator volume (18) is arranged between the inner plate (11) and the outer plate (12), - the acoustic panel (1) comprises an opening (185) coupled to the resonator volume (18), and - the acoustic panel (1) is configured to be mounted to at least one reinforcement bar (22) on an outer wall (210) of the tank (21) wherein the inner plate (21) of the acoustic panel (1) is located closer to the outer wall (210) of the tank (21) than a surface (220) of the reinforcement bar (22) that faces away from the tank (21). Further, an electric appliance (2) and a method of assembling an electric appliance (2) are specified.

The invention relates to a disconnector switch for a high voltage direct current, HVDC, breaker, comprising a contact device (1) comprising a plurality of fixed contacts (6) arranged in a row defining at least one insulating gap (7) between each two fixed contacts (6) and a plurality of moving contacts (5) arranged in another row and each configured for electrically bridging a respective insulating gap (7) in a closed position, an actuating device (2) comprising an axially extending drive rod (8) fixing the plurality of moving contacts (5) and configured for axially moving the another row of the plurality of moving contacts (5) between an open position and the closed position, and an enclosure (3) comprising the contact device (1) and the actuating device (2) arranged therein and filled with a pressurized insulating gas, whereby a radially extending width (9) of at least one of the plurality of fixed contacts (6) is at least eight times greater than an axial gap extension (10) of the least one insulating gap (7).

An acoustic panel (1) for an electric appliance (2) with a tank (21) is specified, wherein - the acoustic panel comprises an inner plate (11) facing the tank (21) and an outer plate facing away from the tank (21), - a volume (13) between the inner plate (11) and the outer plate (12) is filled with a filling material (14), - the acoustic panel (1) is configured to be mounted to at least one reinforcement bar (22) on an outer wall (210) of the tank (21) wherein the inner plate of the acoustic panel (1) is located closer to the outer wall (210) of the tank (21) than a surface of the reinforcement bar (22) that faces away from the tank (21). Further, an electric appliance (2) and a method of assembling an electric appliance (2) are specified.

An acoustic panel (1) for an electric appliance (2) with a tank (21) is specified, wherein - the acoustic panel (1) comprises an inner plate (11) facing the tank (21) and an outer plate (22) facing away from the tank (21), - a volume (13) between the inner plate (11) and the outer plate (12) is subdivided into a plurality of chambers (16), - the acoustic panel (1) is configured to be mounted to at least one reinforcement bar (22) on an outer wall (210) of the tank (21) wherein the inner plate (21) of the acoustic panel (1) is located closer to the outer wall (210) of the tank (21) than a surface (220) of the reinforcement bar (22) that faces away from the tank (21). Further, an electric appliance (2) and a method of assembling an electric appliance (2) are specified.

The present disclosure relates to a method of preparing a system (10), the system (10) including a first device (12) and a second device (14), the second device (14) being configured to act as a backup device to the first device (12), the first device (12) and the second device (14) having a service-oriented architecture, SOA. The method includes: copying a configuration of the first device (12), the configuration including at least one service of the first device (12); applying at least a portion of the copied configuration of the first device (12) to the second device (14); communicatively connecting the first device (12) and the second device (14); sending data from the first device (12) to the second device (14) to at least partially synchronize the second device (14) with the first device (12). The present disclosure also relates to a method of operating a system (10), an apparatus (30) for synchronizing a first device (12) and a second device (14), and a system (10).

A method for producing a first contact layer (5) and a second contact layer (6) on a power semiconductor body (2) is specified, comprising: - providing the power semiconductor body (2), comprising a substrate region (3) with a bottom surface and an epitaxial body region (4) with a top surface facing away from the bottom surface, - applying a first layer on the top surface and applying a second layer on the bottom surface, wherein the first layer comprises a first material comprising titanium, - incorporating a further material into the first layer, wherein the further material comprises phosphorus, and - annealing the power semiconductor body (2) with the first layer comprising the further material and the second layer for a predetermined time interval at a predetermined annealing temperature, such that the first layer and the further material form the first contact layer (5) being a titanium-phosphorus alloy and the second layer forms a second contact layer (6). Furthermore, a power semiconductor device (1) is specified.

An acoustic panel (1) for an electric appliance (2) with a tank (21) is specified, wherein- the acoustic panel comprises an inner plate (11) facing the tank (21) and an outer plate facing away from the tank (21),- a volume (13) between the inner plate (11) and the outer plate (12) is filled with a filling material (14),- the acoustic panel (1) is configured to be mounted to at least one reinforcement bar (22) on an outer wall (210) of the tank (21) wherein the inner plate of the acoustic panel (1) is located closer to the outer wall (210) of the tank (21) than a surface of the reinforcement bar (22) that faces away from the tank (21), and- the acoustic panel (1) comprises a frequency tuning element (4) configured to tune a specific acoustic dampening frequency band of the acoustic panel (1).Further, an electric appliance (2) and a method of assembling an electric appliance (2) are specified.