Hitachi Energy

There is disclosed herein a computer-implemented method (300) for monitoring an static induction device (3), comprising obtaining time-series data (308) comprising monitoring data (307) for the static induction device (3), and decomposing the time-series data (308) into a plurality of layers (310), each layer (310) comprising a subset of the time-series data (308), wherein at least one layer (310) is configured to contain a respective contribution (420) to the monitoring data (308) from a contributor (418). The method (300) further comprises providing each layer (310), as input, to a respective predictive model (312) of a corresponding plurality of predictive models (312) configured to predict future contributions to the monitoring data (310) from the respective contributor (418), and receiving, as output from the plurality of predictive models (312), respective predictions (314) of future contributions from the contributor (418) of each layer (310). Finally, the method (300) comprises aggregating the predictions (314) from each predictive model (312) to thereby obtain predicted monitoring data (316) for the static induction device (3). In this way, the accuracy of the predictions for how the static induction device monitoring data will change is greatly enhanced, enabling a more pro-active control for a power network.

The invention relates to a system (20) for a gas-insulated switchgear (2), comprisinga housing (30) with a flange (32) to be coupled to an electrical component (3), e.g. a disconnector/earthing switch, of the gas-insulated switchgear (2);a low-power instrument transformer (40) arranged in the housing (30) and configured for conducting current and voltage measurements; anda cable end module (50) arranged in the housing (30) and configured for receiving at least one power line (100) to be electrically connected to the electrical component (3) through the flange (32).

The present disclosure relates to a power supporting system (1) comprising an energy storage system (100), ESS, comprising at least one string (S-1, S-M). Each string (S-1, S-M) comprises at least two energy storage racks electrically connected in series. Each energy storage rack comprises at least one energy storage module (ESM-1, ESM-N). Each energy storage module (ESM-1, ESM-N) comprises at least one energy storage cell (C-1, C-2, C-X), and a cell management system (xMS-1, xMS-N) configured to manage said at least one energy storage cell. The power supporting system (1) comprises at least one control device (10, 10-1, 10-M), and at least one primary communication unit (20-1, 20-M), PCU, each PCU (20-1, 20-M) configured to provide a dedicated communication channel between at least one of said at least one control device (10, 10-1, 10-M) and CMSs (xMS-1, xMS-N) of one of said strings (S-1, S-M). Said at least one control device (10, 10-1, 10-M) and said at least one PCU (20-1, 20-M) are arranged remotely relative to said ESS (100). Said at least one control device (10, 10-1, 10-M) is configured to control, by communication via said dedicated communication channels, a remote firmware loading process to update said CMSs (xMS-1, xMS-N) of said at least one string (S-1, S-M). A method of updating CMSs of a power supporting system (1) is also disclosed.

The disclosure provides a subsea electrical connection comprising: an electrical conductor extending along an axial direction of the electrical conductor; and a first flexible bellow surrounding the electrical conductor in a radial direction perpendicular to the axial direction, wherein an inner surface of the first flexible bellow is spaced apart from the electrical conductor in the radial direction.

The present disclosure relates to a control device (20) configured for grid-forming control using a voltage source converter, VSC, (10) electrically connected to a power grid (40) via a point-of-common-coupling, PCC, the control device (20) comprising: a decoupling controller (21) configured to determine a VSC virtual electromotive force (v<EMF>) of said VSC (10) based at least on a first complex signal (K; γ, δ), which first complex signal (K; γ, δ) is based at least on a complex power (S<g>; P<g>, Q<g>) being exchanged between said VSC (10) and the power grid (40), and a complex power reference (S<ref>, P<ref>, Q<ref>) for said complex power (S<g>; P<g>, Q<g>), and a current controller (22) configured to determine a VSC voltage reference (v<c,ref>) for said VSC (10) based at least on a grid voltage (v<g>) for said power grid (40) at said PCC, and a current reference (i<f,ref>) for a current (if) propagating between said VSC (10) and said PCC, a virtual admittance unit (24) configured to determine said current reference (i<f,ref>) based at least on a voltage input (v<in>) multiplied with a virtual admittance (Y<v>), wherein said voltage input (v<in>) is based at least on a voltage difference between said VSC virtual electromotive force (v<EMF>) and said grid voltage (v<g>), and said virtual admittance (Y<v>) is based at least on a virtual impedance between the VSC virtual electromotive force (v<EMF>) and said PCC, wherein the control device (20) is configured to provide said VSC voltage reference (v<c,ref>) to said VSC (10), and wherein said decoupling controller (21) comprises a phase compensation unit (211) configured to apply a phase compensation to said first complex signal (K; γ, δ), which phase compensation is selected to compensate for a phase-shift introduced by said virtual impedance. A method of grid-forming control and a power supporting system is also disclosed.

There is disclosed herein a protection enhancement device (110) for a power network (200), comprising a control module (112) configured to, in response to a detection of a fault current at a detection location in the power grid, control a power device (120) to inject an additional current to supplement the fault current in the power network to thereby cause a protection response on the power network, and/or control a protection device (120) to initiate a protection response on the power network (200). In the latter case, the detected fault current has a different value to a protection response configuration setting for the protection device at which a protection response of the protection device (120) is caused. Also disclosed herein are associated protection methods performable by devices, and a protection system comprising such devices.

The invention relates to an operating mechanism for a switching device (601), comprising a motor (1), an axially extending screw rod (701) and a spindle nut (702), whereby the screw rod (701) is connected to the motor (1) and configured for being rotated by the motor (1), the spindle nut (702) is movable engaged with the screw rod (701) and configured to move linearly along the screw rod (701) when the screw rod (701) rotates, and the screw rod (701) comprises a chamfered thread tip (706) insertable into the spindle nut (702), whereby the chamfered thread tip (706) comprises a first chamfered surface (708) extending in a first angle (α) relative to the axial extension of the screw rod (701) and a second chamfered surface (709) extending in a second angle (β) relative to the axial extension of the screw rod (701) and greater than the first angle (α).

There is disclosed herein an energy storage module (10) for an energy storage system (4) connected to a power grid (2). The energy storage module comprises an energy storage unit (20) having an equivalent capacitance (22). The energy storage unit has an internal resistance (24). The energy storage module further comprises a bypass circuit (30) connected in parallel to the energy storage unit. The bypass circuit comprises a bypass switch (32) and a current limiting device (34) connected in series. A resistance of the current limiting device is less than 500 % of the internal resistance of the energy storage unit. There are also disclosed herein an energy storage system and a power grid system.

The present disclosure relates to a method for monitoring a physical asset, the method comprising: receiving data associated with the physical asset from one or more data sources, wherein the data include measurements of one or more parameters of the physical asset; providing a physical model associated with the physical asset, wherein the physical model includes the one or more parameters of the physical asset; providing one or more cost functions, wherein each cost function is associated with one of a plurality of degradation scenarios; determining, based on the data, the physical model and the cost functions, a most probable degradation scenario of the degradation scenarios; and initiating a mitigation action based on the determined most probable degradation scenario indicating a potential failure.

The present disclosure relates to transformer diagnosis methods for a transformer having a primary side source winding and two secondary side load windings. The method using relations based on a transformer model in which effects of magnetizing currents in the transformer core, leakage inductances and effective resistances of the primary and secondary windings are taken into account, wherein a transformer model of a three-winding transformer is used; transformer currents are measured during variations of the transformer loads wherein the power transferred through the respective windings are proportional; measurements are collected, for at least two different transformer loads, of a selection of primary side currents being indicative of the transformer load; a linear fits is performed by means of relations based on said transformer model, between equivalent load current and the primary current to estimate the value of at least one of the following transformer properties: turn ratio and magnetizing current.