Abstract: A wind turbine includes a rotor having a hub, at least one rotor blade coupled to the hub, and a rotor shaft coupled to said hub for rotation therewith. The wind turbine also includes an electrical generator coupled to the rotor shaft, and a generator-side frequency converter electrically coupled to the electrical generator for converting variable frequency AC received from the electrical generator into DC. The generator-side frequency converter is electrically coupled to an electrical load and is configured to at least one of supply reactive power to the electrical load and absorb reactive power from the electrical load. The wind turbine also includes a grid-side frequency converter electrically coupled to the generator-side frequency converter for converting DC received from the generator-side frequency converter into fixed frequency AC.

Abstract: A wind turbine includes a rotor having a hub, at least one rotor blade coupled to the hub, and a rotor shaft coupled to said hub for rotation therewith. The wind turbine also includes an electrical generator coupled to the rotor shaft, and a generator-side frequency converter electrically coupled to the electrical generator for converting variable frequency AC received from the electrical generator into DC. The generator-side frequency converter is electrically coupled to an electrical load and is configured to at least one of supply reactive power to the electrical load and absorb reactive power from the electrical load. The wind turbine also includes a grid-side frequency converter electrically coupled to the generator-side frequency converter for converting DC received from the generator-side frequency converter into fixed frequency AC.

Abstract: A wind turbine includes a rotor having a hub, at least one rotor blade coupled to the hub, and a rotor shaft coupled to said hub for rotation therewith. The wind turbine also includes an electrical generator coupled to the rotor shaft, and a generator-side frequency converter electrically coupled to the electrical generator for converting variable frequency AC received from the electrical generator into DC. The generator-side frequency converter is electrically coupled to an electrical load and is configured to at least one of supply reactive power to the electrical load and absorb reactive power from the electrical load. The wind turbine also includes a grid-side frequency converter electrically coupled to the generator-side frequency converter for converting DC received from the generator-side frequency converter into fixed frequency AC.

Abstract: A wind turbine includes a rotor having a hub, at least one rotor blade coupled to the hub, and a rotor shaft coupled to said hub for rotation therewith. The wind turbine also includes an electrical generator coupled to the rotor shaft, and a generator-side frequency converter electrically coupled to the electrical generator for converting variable frequency AC received from the electrical generator into DC. The generator-side frequency converter is electrically coupled to an electrical load and is configured to at least one of supply reactive power to the electrical load and absorb reactive power from the electrical load. The wind turbine also includes a grid-side frequency converter electrically coupled to the generator-side frequency converter for converting DC received from the generator-side frequency converter into fixed frequency AC.

Abstract: A system for providing anti-islanding protection of a synchronous machine based distributed generator includes a frequency sensor configured to generate a generator frequency signal, a bandpass filter configured for filtering the generator frequency signal, a governor controller configured for using the filtered frequency signal to generate a power feedback signal, and a governor summation element configured for summing the filtered frequency signal, the power feedback signal, and a reference power to provide an electrical torque signal. Another system includes a voltage sensor configured to generate a generator terminal voltage signal, a feedback power calculator configured for generating a reactive feedback power signal, a bandpass filter configured for filtering the terminal voltage signal, and a PI controller summation element configured for summing the filtered terminal voltage signal, the reactive power feedback signal, and a reference reactive power to provide an error signal.

Abstract: A method for detecting islanding conditions in an electrical grid having a power line voltage includes monitoring a detectable signal different from the power line voltage at a generating station, superimposing the detectable signal onto the power line voltage at a grid point outside the generating station, and switching the generating station from a grid-connected mode of operation to an islanded mode of operation when the signal to which the detector is responsive is determined to be absent.

Abstract: A system for providing anti-islanding protection of a synchronous machine based distributed generator includes a frequency sensor configured to generate a generator frequency signal, a bandpass filter configured for filtering the generator frequency signal, a governor controller configured for using the filtered frequency signal to generate a power feedback signal, and a governor summation element configured for summing the filtered frequency signal, the power feedback signal, and a reference power to provide an electrical torque signal. Another system includes a voltage sensor configured to generate a generator terminal voltage signal, a feedback power calculator configured for generating a reactive feedback power signal, a bandpass filter configured for filtering the terminal voltage signal, and a PI controller summation element configured for summing the filtered terminal voltage signal, the reactive power feedback signal, and a reference reactive power to provide an error signal.

Abstract: An apparatus for anti-islanding protection of a distributed generation with respect to a feeder connected to an electrical grid is disclosed. The apparatus includes a sensor adapted to generate a voltage signal representative of an output voltage and/or a current signal representative of an output current at the distributed generation, and a controller responsive to the signals from the sensor. The controller is productive of a control signal directed to the distributed generation to drive an operating characteristic of the distributed generation out of a nominal range in response to the electrical grid being disconnected from the feeder.

Abstract: Real and reactive power control for wind turbine generator systems. The technique described herein provides the potential to utilize the total capacity of a wind turbine generator system (e.g., a wind farm) to provide dynamic VAR (reactive power support). The VAR support provided by individual wind turbine generators in a system can be dynamically varied to suit application parameters.

Abstract: A static series voltage regulator (SSVR) for an electric power distribution system protects a load on a feeder branch from voltage dips by boosting voltage under certain conditions. The SSVR contains a 3-phase voltage source inverter and a source bridge, fed from a source, supplying the dc side of the inverter. A series transformer is connected between the power source and a load coupling the inverter output to appear between the power source and the load. A surge filter connected in parallel with the series transformer protects the load from fast front voltage pulses produced by the inverter, and isolation and bypass switches isolate the inverter and series transformer from the power source and load. The inverter is controlled so that during normal operation it acts as a short on the series transformer, and, during a fault that causes a dip in the source voltage, it injects voltage in series with the source voltage to provide a boost action to maintain load voltage at a desired magnitude and balance.