Abstract: A power distribution system for providing a desired value of voltage regulation is presented. The system includes at least one power source, at least one sink, a distribution feeder configured to couple the at least one power source to the at least one sink. The system includes a plurality of modular voltage regulation units coupled to the distribution feeder, where each of the plurality of modular voltage regulation units includes a transformer including a primary winding having a first end and a second end and a secondary winding having a first end and a second end; and at least one switch coupled to the primary winding of the transformer, where the first end of the secondary winding is coupled to at least one of the first and second ends of the primary winding via the at least one switch. A method of operating a power distribution system is also presented.

Abstract: A method for inspecting a solar panel of a solar power station is performed in a controller for an unmanned aerial vehicle, UAV, and includes the steps of: receiving an inspection request for a subset of the solar panels navigating, in a first stage, using radio signals, the UAV to an initial location in a vicinity of a particular solar panel of the subset of solar panels; positioning, in a second stage, the UAV using at least one near field sensor of the UAV; and capturing, using the infrared camera, an image of the particular solar panel.

Abstract: A method for controlling plant active power output ramp rate of a power plant to a PCC with a power grid includes obtaining information about a current RES active power output of a Renewable Energy Source (RES) in the power plant. The method also includes forecasting future RES active power output, during a predefined future time period. The method also includes, based on the obtained current RES active power output information and on the forecasted RES active power output, determining whether an expected ramp rate of the RES active power output during the predefined time period exceeds a predefined maximum ramp rate limit of a plant active power output.

Abstract: Apparatuses, systems and methods for providing a remote user computing system with secure wireless diagnostic and programming access to an IED operatively coupled with electrical substation equipment are disclosed. An exemplary apparatus comprises a portable computer system comprising a processor and one or more non-transitory memory media storing executable instructions and a cellular modem in operative communication with one another. An antenna external to the portable computer system is adapted to be operatively coupled with the cellular modem and physically positionable independently from the portable computer system. A communication interface adapted to establish a physical electronic communication link between the portable computer system and the IED. The portable computer system, the antenna and the communication interface being provided in a human portable kit.

Abstract: An uninterruptable power supply system is disclosed with a precharge converter for connecting to a DC link of the uninterruptable power supply system to a DC power supply, whereby the DC link comprises a first and a second DC bus line, which are both coupled to a common reference point, whereby the common reference point can be an AC power supply neutral of the uninterruptable power supply system, comprising power connectors for connecting to the DC power supply, a first and second output connector for connecting to the first and the second DC bus line, respectively, a converter circuit for receiving DC power from the power connectors and providing DC power to the first and second output connector, and a control unit for controlling operation of the converter circuit.

Abstract: A method for controlling a modular multi-level converter comprises the steps of: collecting control input variables from the converter; transmitting the control input variables to a controller of the converter via a first communication medium; determining, in the controller, and actual state of the converter and at least one control output variable based on a model of the converter; and transmitting the control output variable to the converter for controlling the converter via a second communication medium. The model of the converter accounts for the first and/or the second communication medium.

Abstract: A transformer system includes a transformer and a transformer tank. The transformer tank houses the transformer in a bath of a dielectric fluid. The transformer system also includes a controller, and a fiber optic sensor communicatively coupled to the controller. The fiber optic sensor is disposed in the dielectric fluid and operative to provide an output that varies with the level of the dielectric fluid. The controller is operative to determine the level of the dielectric fluid based on the output of the fiber optic sensor.

Abstract: An electrical multi-phase converter and method for controlling an electrical multi-phase converter is disclosed. In one form a method provides for controlling the electrical multi-phase converter comprises: determining at least two supply voltages for the at least two converter cells of the at least two phase branches; determining a potential zone for each phase branch based on the at least one supply voltage of the at least one converter cell of the phase branch, the potential zone bounding a possible actual phase voltage producible by the phase branch; receiving a reference voltage for each phase branch; and, if the reference voltage for a phase branch is not within the potential zone of the phase branch, setting the reference voltage to a bound of the potential zone and shifting reference voltages of other phase branches, wherein the reference voltages are set and shifted such that a minimal common mode voltage between the output voltages of the multi-phase converter is generated.

Abstract: An uninterruptible power supply (UPS) system is provided. The UPS system includes a plurality of UPSs, a ring bus coupled to the UPSs, a plurality of chokes, and at least one static switch coupled between an associated UPS of the UPSs and the ring bus. Each choke electrically couples an associated UPS to the ring bus. The static switch is switchable to selectively bypass at least one choke.

Abstract: An electrical chain-link converter system includes a converter phase leg for converting a plurality of DC electrical currents from a plurality of DC power sources to an AC current of an electrical power distribution network. The phase leg includes a plurality of serially connected converter cells each of which is connected to a respective power source of the plurality of DC power sources. The system also includes a control unit associated with the phase leg, the control unit including a processor; and a storage unit storing instructions that, when executed by the processor, cause the control unit to, for each of the converter cells: obtain a dedicated voltage reference for the converter cell; and transmit the voltage reference to the converter cell.

Abstract: A method performed in an electrical microgrid for facilitating connection of a first and second AC power networks. The method includes, when the power networks are disconnected, from the second power network, controlling the AC frequency of the first power network based on the AC frequency of the second power network for ensuring that when the first and second networks are connected power will flow from the power network of the first and second power networks having a higher frequency to the power network of the first and second power networks having a lower frequency. The method also includes, after the controlling, connecting the first power network to the second power network, whereby power, at the instant of connecting, flows from the power network of the first and second power networks having a higher frequency to the power network of the first and second power networks having a lower frequency.

Abstract: The present invention comprises an apparatus and method for detecting a loss of oil from an oil-immersed transformer, based on fitting a transformer top-oil temperature model to online measurements in an iterative optimization process that yields fitted values for a first model parameter representing the top-oil temperature rise over ambient temperature and a second model parameter representing the oil time constant. Among the several advantages seen in the contemplated apparatus and method is the reduction in required instrumentation, whereby transformer oil leaks are indirectly detected without requiring pressure sensors or mechanical floats, although the presence of such sensors is not excluded by the teachings herein.

Abstract: A multi-level power converter for one or more phases includes one or more converter arms including a plurality of serial connected switching cells. Each switching cell includes a plurality of switching devices, a primary energy storage, a secondary energy storage and a first inductor. The switching devices are arranged to selectively provide a connection to the primary energy storage, wherein each switching cell includes a bridge circuit including the switching devices and the primary energy storage, a battery circuit connected to the bridge circuit and including the secondary energy storage, and an arm circuit providing a connection between two adjacent switching cells. The first inductor of each switching cell is arranged in the arm circuit.

Abstract: A method for controlling a modular multilevel converter to reduce the lower order harmonics generated by the converter is provided. The method may also reduce the overall switching loss of the converter by switching the switches close to fundamental switching frequencies while still reducing the lower order harmonics that are generated.

Abstract: A method for data transfer of an electric device configuration, the electric device configuration comprising a plurality of converter devices including a first converter device and a second converter device, each of the converter devices comprising a first converter unit having a first power connection and a second power connection, the first power connection arranged to supply direct current power to the first converter unit and the second power connection arranged to supply electric power from the first converter unit, and the first power connections of the first converter units being electrically connected to one another.