Abstract: An AC-to-AC modular multilevel converter (MMC) is configured to be connected between a three-phase AC system and a single-phase AC system. The MMC includes a number of converter arms connected in a ring to allow a circulating current to be circulated in the ring through each of the converter arms. Each converter arm includes series-connected converter cells. Phase terminals are arranged in the ring between the converter arms such that each of the converter arms is separated from neighboring converter arms by at least one of the phase terminals. The phase terminals include respective terminals for each of a first phase, a second phase and a third phase of the three-phase AC system and respective terminals for each of a positive conductor and a negative conductor of the single-phase AC system.

Abstract: To determine system settings for an industrial system, digital twin data of a digital twin of the industrial system is retrieved. System simulations of the industrial system are performed based on the digital twin data to explore candidate system settings for the industrial system prior to application of one of the candidate system settings to the industrial system. At least one optimization objective or at least one constraint used in the system simulations is changed while the system simulations are being performed on an ongoing basis. The results of the system simulations are used to identify one of the candidate system settings for application to the industrial system.

Abstract: A submersible inspection drone used for inspection of liquid cooled electrical transformers can include a number of separate cameras for imaging the internal structure of the transformer. The submersible can be configured to communicate to a base station using a wireless transmitter and receiver. The cameras on the submersible can be fixed in place and can be either static or motion picture cameras. The submersible can include an input/output selector capable of switching between the camera images, either through commanded action of a user or through computer based switching. In one form the input/output selector is a multiplexer. The base station can be configured to display images from the cameras one at a time, or can include a number of separate viewing portals in which real time images are displayed. The base station can include a demultiplexer synchronized to the multiplexer of the submersible.

Abstract: A method, a node and a detector for detecting an interfering signal in a wireless network communication system comprising a network manager and several nodes, each node (202B) comprising a detector (204) for receiving input signals from at least one antenna, a delay component (205) for delaying a received input signal, and a receiver (206RX) for determining an energy pattern of expected received input signals. The detector (204) is configured to send an alarm signal to the receiver (206RX) depending on the presence or absence of an interfering signal from an interferer 203 and an active/inactive state of the receiver (206RX).

Abstract: A telescopic electric conductor includes an electrically conductive first tube having a longitudinal axis and an electrically conductive second tube movable relative to the first tube along the longitudinal axis while being at least partly received within the first tube. An electrically conductive flexible self-supporting element is arranged inside the first tube and is mechanically and electrically connected to the first tube and to the second tube. The flexible element is arranged to elastically deform along the longitudinal axis. The flexible element has a waveform shape with several cycles of the waveform includes a number of sections that are welded together, each section having a shape of a half cycle of the waveform.

Abstract: A method for monitoring a circuit breaker includes measuring at least two operating condition related parameters of the circuit breaker during operation of the circuit breaker; obtaining first data representing a vector having at least two components respectively representing the at least two measurements of the at least two parameters; judging location of the vector represented by the obtained data with respect to a vector space having an envelope separating healthy and unhealthy status of the circuit breaker, where the envelope has at least one portion of curvature; and generating a signal indicating the health status of the circuit breaker in consideration of the location of the vector if it is outside of the envelope.

Abstract: A wet capacitor is provided, and the use of an insulation fluid composition in such a capacitor. The capacitor includes a package of a metal foil and a polymeric insulating film, or of a metallized polymeric film, wherein the insulation composition includes a synthetic or natural aromatic oil and a polymer. The insulation composition is configured to undergo a thermo-reversible oil-to-gel transition at a predefined gel-point temperature. Further, methods of producing such wet capacitors are provided, optionally including additional filling materials, and methods of sealing leaks in such capacitors.

Abstract: A method for manufacturing an electric winding of an electromagnetic induction apparatus includes providing a conductor structure and forming an electric winding by means of the conductor structure. The conductor structure includes a conductor element extending longitudinally along a main extension direction and one or more spacer bands arranged on corresponding lateral surfaces of the conductor element. Each spacer band includes a supporting structure made of electrically insulating material and spacer elements made of electrically insulating material arranged on the supporting structure. The spacer elements are spaced one from another along the supporting structure. The electric winding extends axially along a winding direction and has a plurality of turns arranged around the winding direction. Each turn of the electric winding is formed by a corresponding longitudinal portion of the conductor element.

Abstract: A condenser includes a fluid inlet in an upper manifold and a fluid outlet in a lower manifold. The condenser includes multiport tubes provided with a plurality of separate flow channels which are delimited by outer opposite side walls and internal intermediate walls extending between the outer opposite side walls of the tubes. The multiport tubes define a channel space between them. A plurality of cooling plates extend between the upper manifold and the lower manifold. The cooling plates are in thermal contact with the multiport tubes to receive a heat load from fluid in the flow channels. The cooling plates have outer edges which protrude out from the channel space and are directed away from the channel space.

Abstract: Embodiments of present disclosure relate to a capacitor assembly and a dry-type capacitor. The capacitor assembly includes: a first layer of capacitor elements; a second layer of capacitor elements, wherein the first layer of capacitor elements is stacked on the second layer of capacitor elements; a first busbar comprising a first conductive plate provided with a plurality of holes, wherein the first conductive plate is electrically coupled to the capacitor elements of the first layer via a plurality of connecting elements arranged at the respective holes of the first conductive plate; and a second busbar electrically coupled to the first busbar and including a second conductive plate provided with a plurality of holes, wherein the second conductive plate is electrically coupled to the capacitor elements of the second layer via a plurality of connecting elements arranged at the respective holes of the second conductive plate.

Abstract: Provided is a spring drive cam for a spring drive of a circuit breaker including a disc-like shape configured for rotating around a rotation axis in the spring drive, whereby the disc-like shape comprises a radius (R) that changes depending on an angle (?) of the radius (R) relative to a base angle (?0), and whereby a rate (dR/d?) defined by a change of the radius (R) per change of the angle (?) is ?0.3 mm/°.

Abstract: The present disclosure relates to a transformer system comprising a power transformer including a metal tank filled with an electrically insulating liquid, and a wireless sensor arrangement submerged in the insulating liquid within the tank. The sensor arrangement includes a radio transmitter for wirelessly transmitting sensor readings to the outside of the transformer through an opening in the tank, said opening being provided with a liquid-tight seal comprising a solid insulator for preventing leakage from the tank of the insulating liquid and wherein the radio transmitter is configured for transmitting the sensor readings using a carrier frequency within the range of from 100 kHz to 1 MHz.

Abstract: A switching circuit for a voltage source converter includes a string of series-connected switches and a string of capacitors. A first conductor interconnects a first end of the string of series-connected switches with a first end of the string of capacitors at a first switch and a second conductor interconnects a second end of the string of series-connected switches with a second end of the string of capacitors at a second switch. A first string of components is connected between the first end of the string of series-connected switches and the first end of the string of capacitors and includes a snubber component for the first switch. A second string of components is connected between the second end of the string of series-connected switches and the second end of the string of capacitors and includes a snubber component for the second switch.

Abstract: Techniques for assessing a health of a transformer breather are provided. The transformer breather contains a desiccant and is in fluid communication with an expansion tank of a fluid-insulated transformer. A weight measurement that is dependent on a weight of the transformer breather or of a component or sub-assembly thereof is processed to assess the health of the transformer breather.

Abstract: A locking arrangement can be used for securing electric module cards between two side walls of a housing. The locking arrangement includes two side members for fixed arrangement with the respective side walls. An opening defined between the side members accommodates electric contacts of the electric module cards. A first and a second transverse member form a frame with the side members in order to lock the electric module cards within the housing. A locking mechanism is detachably connects at least one of the transverse members to at least one of the side members by means of a snap-fit.

Abstract: There is provided a pressboard for high-voltage devices, the pressboard having a density of 0.6-1.3 g/cm3 according to IEC60641-2, and including 1-15% microfibrillated cellulose, MFC, based on the total dry weight of the pressboard. There is also provided an insulation element including such pressboard, wherein the pressboard is impregnated with an electrically insulating compound. There is also provided use of such insulation element in a high-voltage device as well as a high-voltage device comprising such insulation element, wherein the high-voltage device may be a power transformer.

Abstract: Examples of operating an Intelligent Electronic Device (IED) during power swings, are described. In an example, voltage measurements for a phase is received and sampled. Root mean square (RMS) values of the voltage samples is calculated based on the voltage measurements. Delta quantities for each phase are calculated based on the RMS values. Each of the RMS values and delta quantities are associated with respective sampling instants. In response to a delta quantity being greater than a predefined threshold, a peak delta quantity is detected. A time interval between a sampling instant associated with the peak delta quantity and a sampling instant associated with a first delta quantity is determined. Based on a comparison of the time interval with a threshold time, a disturbance condition may be detected as a power swing and consequently, fault detection at the IED may be blocked.

Abstract: A method of operating a power grid includes: generating, by a power management system of the power grid, an intermediate resource allocation schedule that provides a tentative schedule of resource allocation for power grid resources operating within the power grid; determining, by the power management system, whether the intermediate resource allocation schedule is feasible by checking whether the intermediate resource allocation schedule satisfies coupling constraints of a power grid resource allocation profile of the power grid indicative of an operation of the power grid constrained by power grid operational information; and in response to determining that the intermediate resource allocation schedule is infeasible, repairing, by the power management system, the intermediate resource allocation schedule to generate a feasible resource allocation schedule, where the repairing comprises determining whether a first dispatch solution obtained by solving a dispatch problem with fixed integer decisions from the

Abstract: A method of controlling a microgrid includes receiving, by a power management system, PMS, of the microgrid, operating point values for a plurality of controllable assets. The method includes determining, by the PMS, an asset headroom. The method includes determining, by the PMS, a modified operating point value that is dependent on the received operating point value of the controllable asset, the determined asset headroom of the controllable asset, and a total power offset of the microgrid. The method includes controlling, by the PMS, the controllable assets for which the modified operating point values have been determined in accordance with the modified operating point values.

Abstract: A transformer includes an outer cabinet and an inner tank. The outer cabinet includes a base configured to be installed below ground level, a housing wall configured to be installed at least partially below ground level, and a sill coupled to the housing wall and configured to be installed above ground level. The sill includes a top access opening between an interior space of the outer cabinet and an exterior of the outer cabinet. The inner tank is disposed on the base at least partially below ground level and includes an active part including a transformer circuit. The inner tank includes a plurality of terminals electrically coupled to the active part, each terminal extending from the inner tank into the interior space of the outer cabinet along a respective terminal axis that passes through the top access opening at a respective upward angle with respect to ground level.