Abstract:
A method for maintaining network lifetime of a wireless network in wireless communication system, the network including a plurality of device nodes. Selected ones of the wireless nodes have assigned roles in the wireless network. To improve and maintain network lifetime the method includes determining a below threshold operating condition of a first sensor node assigned to a first role and re-assigning the first role to another second node in said network. In other aspects of the invention a method, system and a computer program for carrying out the method are described.
Abstract:
Methods, systems, and computer readable media for adaptive out of step protection for power generators with load resynchronization capability are disclosed. According to one method, when a fault condition occurs in a load being supplied by a power generator, a number of pole slips expected to occur in the generator due to the fault before resynchronization is estimated. It is determined whether the estimated number of pole slips exceeds a threshold. An offline or online status of the generator is controlled based on the determination as to whether the estimated number of pole slips exceeds the threshold.
Abstract:
A battery energy storage arranged to be connected to a capacitor link, which is connected in parallel to a power converter. The battery energy storage includes a battery module and a direct current energy source connected in series with a voltage source converter. The voltage source converter is adapted to insert a positive voltage when the voltage of the battery module falls below a first threshold value, and to insert a negative voltage when the voltage of the battery module exceeds a second threshold value. The direct current energy source is adapted to be either charged or discharged during the voltage insertion by the voltage source converter. The disclosure also provides a battery energy storage system including such battery energy storage.
Abstract:
It is presented a method of controlling fluid flow in a fluid network system by means of a plurality of fluid machines. The method comprises the steps of a) obtaining a respective current fluid flow rate associated with each fluid machine, b) obtaining a current fluid machine speed of each fluid machine, c) obtaining desired fluid flow rates in the fluid network system, d) determining a new fluid machine speed for each fluid machine based on the current fluid machine speeds and a change in the fluid machine speed required to obtain the desired fluid flow rates, wherein the change in the fluid machine speed is determined by minimizing a total fluid machine power which is a function dependent of the change in the fluid machine speed, the minimization being performed with constraints for fluid flow rate, fluid machine pressure and fluid machine speed, and e) controlling the speed of the plurality of fluid machines according to the new fluid machine speeds such that the minimum total fluid machine power in the fluid network system is attained. A computer program product and a control system are also presented herein.
Abstract:
A permanent magnet machine with a hybrid cage and methods for operating same are disclosed. According to one aspect, the subject matter described herein includes a rotor and hybrid cage for an electrical machine, the rotor comprising a rotor body having a central axis and including a plurality of permanent magnets positioned to create a plurality of rotor magnetic poles distributed around a peripheral surface of the rotor. The rotor also includes a hybrid cage that includes conductive loops around each of the rotor magnetic poles, where the conductive loops are controllable to form a closed circuit or an open circuit around each of the rotor magnetic poles. A closed circuit may be created when a magnetic field having a field strength or change of field strength that exceeds a threshold magnitude is present, such as during a fault condition, and an open circuit may be created when a magnetic field having a field strength or change of field strength that exceeds a threshold magnitude is not present, such as during normal operation.
Abstract:
A method for identifying a fault condition in an electrical machine in which at least a stator or a rotor has parallel winding branches is disclosed. A measurement is carried out for obtaining a set of circulating current values between two parallel winding branches of which each winding branch includes a single coil. A frequency analysis is applied on the set of circulating current values to obtain at least one frequency component. A fault condition of the electrical machine is determined on the basis of the at least one frequency component.
Abstract:
A protection relay is disclosed that generates a trip signal to operate a circuit breaker in case of a fault condition. A first module provides measurement and analysis of power parameters of the power line connecting the power equipment that is being protected, the protection being provided by generating a first trip signal for operating a circuit breaker connected in the power line. One or more second modules can boost performance of the protection relay by measurement and analysis of power parameters-to generate a second trip signal for operating a circuit breaker connected in the power line. The first trip signal and the second trip signal are logically combined to generate a trip signal that operates the circuit breaker.
Abstract:
A method is provided for detecting islanding conditions in an electric power network which includes a plurality of sub-networks. The sub-networks include at least one power electrical unit and are separable from each other and a main grid supplying the network by switching devices. The method includes determining topological information of at least one sub-network of interest, detecting islanding conditions in at least one sub-network of interest on the basis of the topological information by using separate detecting devices for each sub-network of interest, and sending, on the basis of the islanding conditions detected by using the detecting devices, a disconnect signal to at least one power electrical unit in at least one sub-network of interest.
Abstract:
A method of monitoring an industrial process by means of an ear protection system having an ear protection unit with a left speaker and a right speaker includes obtaining a direction from which a sound is to be provided based on an angle between a coordinate system defined by the ear protection unit and a coordinate system defined by an industrial process environment of the industrial process, and on a location of the origin of the coordinate system of the ear protection unit in the coordinate system of the industrial process environment relative a location of an industrial process component in the coordinate system of the industrial process environment; obtaining real-time process variable data relating to at least one process variable of the industrial process component; and providing a 3-d sound that simulates an origination from the direction by means of at least one of the left speaker and the right speaker, which 3-d sound is indicative of a state of the industrial process component, wherein the 3-d sound simulates a realistic sound of the at least one process variable, reflecting a real-time state of the at least one process variable. An ear protection system carrying out the method is also presented herein.
Abstract:
A network management agent, device or module determine the network topology of a communication network based on at least one neighbor network or end device identity and corresponding network link communication delay collected from, determined by, and stored in a Management Information Base of, at least one first network device of the communication network. Neighbor identities and communication delays are determined according to the IEEE 1588 standard.