Abstract:
An electrical machine with a rotor or the stator including a plurality of discrete field modules, and the other one of the rotor and the stator including a plurality of armature coils connected to different power converters. Each field module includes one or more field coils which can be activated independent of the field coils of the neighbouring field modules. When at least one of the field coils is inactivated, e.g. because of a defect, each of the power converters is allowing less power to pass through when an armature coil connected to it is moving over an inactivated field coil, and more power to pass through when the armature coil connected to it is moving over an activated field coil.
Abstract:
A method of producing a layer of a UV-cured silicone rubber composition on a substrate surface, including applying a primer composition to the substrate surface and hardening the primer composition followed by applying a UV-curable silicone rubber composition, and UV-curing the curable silicone rubber composition. At least one UV-sensitive crosslinking catalyst selected from compounds which initiate and promote curing of UV-curable silicone rubber compositions, is added to the silicone primer composition in any desired sequence before, during or after hardening of the silicone primer composition.
Abstract:
The teachings herein disclose an advantageous method and apparatus for performing Security Constrained Economic Dispatch (SCED) for a hybrid power system that includes one or more AC grids interconnected with one or more multi-terminal High Voltage DC (HVDC) grids. The teachings include optimizing a non-linear objective function, subject to a set of constraints that include AC and DC grid constraints, for determining the SCED solution using successive linear approximation. The linear programming model used in the linear approximations is advantageously augmented with a DC grid portion in a manner that accounts for the effects of the DC grid on the AC grid, but which does not require exposing proprietary DC grid modeling details, and which conforms the resultant SCED solution to all applicable AC and DC grid constraints, including AC grid line flow constraints, AC grid power balance constraints, DC grid line flow constraints, and DC grid power balance constraints.
Abstract:
A method for controlling an energy storage system for connection to a power system, and such an energy storage system are provided. The method makes use of a model based predictive controller to optimize the charging/discharging rates of energy storage elements in a hybrid energy storage system. The method includes determining respective desired charging/discharging rates for the energy storage elements in dependence upon state of charge predictions from respective models of the storage elements, using model predictive control, and adjusting respective charging/discharging rates of the storage elements in accordance with the determined rates. The energy system includes a controller configured to control respective charging/discharging rates of the energy storage elements in accordance with the method.
Abstract:
A gapped core leg for a shunt reactor, comprising magnetic core elements separated by spacers cast directly between the core elements. Accordingly, a rigid core leg construction is achieved.
Abstract:
A power distribution system has a plurality of reactive power resources including capacitor banks and distributed energy resources connected to branches of the power distribution system. Power loss is reduced in the distribution system by determining discrete switch states for the capacitor banks and continuous set points for the distributed energy resources, so that the reactive power provided by the reactive power resources reduces power loss while optionally correcting voltage violations in the power distribution system when the capacitor banks are set in accordance with the respective discrete switch states and the distributed energy resources are operated at the respective continuous set points. The range of values for the continuous set points is constrained based on maximum and minimum reactive power limits for each distributed energy resource under consideration.
Abstract:
The present invention discloses a fast power swing unblocking method and apparatus for a distance protection in a power system, which is able to ensure fast phase-segregated tripping of distance protection for faults during a power swing (3-phase or 2-phase swing). The power swing unblocking method in a power system according to the present invention comprises calculating changing rates of impedances for all operating loops of the distance protection in the power system; and determining a fault loop based on the calculated changing rates. If there is a fault loop, a blocked distance zone for the fault loop is unblocked. Before calculating the changing rates, whether the power system is under a power swing is checked and a distance zone that might mal-operate under the power swing is blocked if it is checked that the power system is under the power swing. By applying this invention, the performance of the distance protection during power swings can be improved, and the distance protection can ensure faster and phase-segregated operation, which are very beneficial for the system reliability.
Abstract:
The invention concerns a voltage source converter (26) comprising a group of phase legs, at least three connection terminals (AC1, AC2, AC3, DC+, DC−) for connecting the phase legs to power transmission elements, a first group of cells (C1p1, C2p1, C1n1, C2n1, C1p2, C2p2, C1n2, C2n2, C1p3, C2p3, C1n3, C2n3) in each phase leg and a second group of cells (C3p1, C3n1, C3p2, C3n2 C3p3, C3n3). The cells (C1p1, C2p1, C1n1, C2n1, C1p2, C2p2, C1n2, C2n2, C1p3, C2p3, C1n3, C2n3) in the first group are only capable of providing unipolar voltage contributions to the converter and connected for only being capable of such unipolar voltage contributions, while the cells (C3p1, C3n1, C3p2, C3n2 C3p3, C3n3) in the second group are connected to the corresponding cells of the first group and arranged to have bipolar voltage contribution capability.
Abstract:
A method for communication in a wireless sensor network of an industrial control system. The network includes a plurality of device nodes and at least one gateway. The method includes aggregating in at least one wireless device data originating from at least two data packets. The method includes receiving at a first node at least one first data packet for a first destination address and aggregating data from the at least one data packet with data from at least one second data packet, intended for the same first destination address, forming an aggregated data packet and sending the aggregated data packet to another node or to said gateway. In other aspects of the invention a method, system and a computer program for carrying out the method are described.
Abstract:
Converter stations have real and reactive power set points initially determined as part of a main loadflow analysis routinely performed on the AC power system connected to the converter stations. Viable real and/or reactive power set points for the converter stations can be identified by calculating real and/or reactive power set point candidates for the converter stations before the main loadflow analysis is performed again on the AC power system. The power set point candidates are calculated based on information determined as part of a previous iteration of the main loadflow analysis on the AC power system. The power set point candidates which violate an operating constraint imposed on the AC power system are identified, and a region of valid power set points is defined for the converter stations that excludes the power set point candidates which violate an operating constraint imposed on the AC power system.