Abstract: The present disclosure relates to a wind turbine comprising a wind turbine rotor with a plurality of blades supported on a support structure, a generator operatively coupled to the wind turbine rotor for generating electrical power, a power electronic converter for converting electrical power generated by the generator to a converted AC power of predetermined frequency and voltage, and a main wind turbine transformer having a low voltage side and a high voltage side for transforming the converted AC power to a higher voltage. One or more electric filters are connected to the high voltage side of the main transformer, wherein the electric filters are arranged in the support structure. The present disclosure also relates to wind farms, and particularly offshore wind farms, and to methods for operating wind farms.

Abstract: The present disclosure relates to a wind turbine comprising a wind turbine rotor with a plurality of blades supported on a support structure, a generator operatively coupled to the wind turbine rotor for generating electrical power, a power electronic converter for converting electrical power generated by the generator to a converted AC power of predetermined frequency and voltage, and a main wind turbine transformer having a low voltage side and a high voltage side for transforming the converted AC power to a higher voltage. One or more electric filters are connected to the high voltage side of the main transformer, wherein the electric filters are arranged in the support structure. The present disclosure also relates to wind farms, and particularly offshore wind farms, and to methods for operating wind farms.

Abstract: A voltage control arrangement for a system of multiple windfarms with transmission lines. Voltage is regulated at a point of regulation on the system, such as a high voltage substation or other system bus. Regulation is achieved at the point of regulation by sensing the voltage, comparing to a reference voltage, and adjusting the reactive power output of the wind turbines and other equipment in the system. The regulation point may be shifted to another point if needed to respect voltage limits at that points of the system after attempting to shift reactive load to restore voltage within limits at the other points in the system. The reference voltage may be adjusted to minimize losses for the system of multiple windfarms and transmission lines. A loss optimizing algorithm is applied to the combined multiple windfarm and transmission line to shift reactive load among local windfarms to minimize losses and to shift reactive load among individual wind turbines within an individual windfarm.

Abstract: A system is provided for compensating a power transmission line having one or more non-conventional power generating sources connected to the power transmission line. At least one series compensation circuit is connected to a portion the power transmission line, and at least one damping circuit is connected in parallel with the series compensation circuit. The damping circuit reduces subsynchronous series resonance caused by the series compensation circuit on the power transmission line, and the series compensation circuit compensates the power transmission line.

Abstract: A voltage control arrangement for a system of multiple windfarms with transmission lines. Voltage is regulated at a point of regulation on the system, such as a high voltage substation or other system bus. Regulation is achieved at the point of regulation by sensing the voltage, comparing to a reference voltage, and adjusting the reactive power output of the wind turbines and other equipment in the system. The regulation point may be shifted to another point if needed to respect voltage limits at that points of the system after attempting to shift reactive load to restore voltage within limits at the other points in the system. The reference voltage may be adjusted to minimize losses for the system of multiple windfarms and transmission lines. A loss optimizing algorithm is applied to the combined multiple windfarm and transmission line to shift reactive load among local windfarms to minimize losses and to shift reactive load among individual wind turbines within an individual windfarm.

Abstract: A system for compensating a power transmission grid is provided. The system includes one or more non-conventional power generating sources that are connected to the power transmission grid. At least one series compensation circuit is connected to at least a portion of the power transmission grid, to compensate the power transmission grid. At least one damping circuit is connected to at least a portion of the power transmission grid, and it mitigates subsynchronous series resonance caused by the series compensation circuit on the power transmission grid.

Abstract: A voltage control arrangement for a system of multiple windfarms with transmission lines. Voltage is regulated at a point of regulation on the system, such as a high voltage substation or other system bus. Regulation is achieved at the point of regulation by sensing the voltage, comparing to a reference voltage, and adjusting the reactive power output of the wind turbines and other equipment in the system. The regulation point may be shifted to another point if needed to respect voltage limits at that points of the system after attempting to shift reactive load to restore voltage within limits at the other points in the system. The reference voltage may be adjusted to minimize losses for the system of multiple windfarms and transmission lines. A loss optimizing algorithm is applied to the combined multiple windfarm and transmission line to shift reactive load among local windfarms to minimize losses and to shift reactive load among individual wind turbines within an individual windfarm.

Abstract: Systems and methods are provided for reactive power regulation and voltage support for renewable energy plants. In one embodiment, a system and method are provided for coordinating voltage and reactive power output of a plant with one or more requirements associated with a utility. The method can include generating a VAR regulator output signal based at least in part on a reactive power control signal received from a utility, controlling reactive power and voltage output of the one or more power sources based at least in part on the generated VAR regulator output signal, aggregating reactive power output or the one or more power sources, and providing the aggregated reactive power to the utility.

Abstract: Systems and methods are provided for reactive power regulation and voltage support for renewable energy plants. In one embodiment, a system and method are provided for coordinating voltage and reactive power output of a plant with one or more requirements associated with a utility. The method can include generating a VAR regulator output signal based at least in part on a reactive power control signal received from a utility, controlling reactive power and voltage output of the one or more power sources based at least in part on the generated VAR regulator output signal, aggregating reactive power output or the one or more power sources, and providing the aggregated reactive power to the utility.

Abstract: A system is provided for compensating a power transmission line having one or more non-conventional power generating sources connected to the power transmission line. At least one series compensation circuit is connected to a portion the power transmission line, and at least one damping circuit is connected in parallel with the series compensation circuit. The damping circuit reduces subsynchronous series resonance caused by the series compensation circuit on the power transmission line, and the series compensation circuit compensates the power transmission line.

Abstract: A system for compensating a power transmission grid is provided. The system includes one or more non-conventional power generating sources that are connected to the power transmission grid. At least one series compensation circuit is connected to at least a portion of the power transmission grid, to compensate the power transmission grid. At least one damping circuit is connected to at least a portion of the power transmission grid, and it mitigates subsynchronous series resonance caused by the series compensation circuit on the power transmission grid.

Abstract: A voltage control arrangement for a system of multiple windfarms with transmission lines. Voltage is regulated at a point of regulation on the system, such as a high voltage substation or other system bus. Regulation is achieved at the point of regulation by sensing the voltage, comparing to a reference voltage, and adjusting the reactive power output of the wind turbines and other equipment in the system. The regulation point may be shifted to another point if needed to respect voltage limits at that points of the system after attempting to shift reactive load to restore voltage within limits at the other points in the system. The reference voltage may be adjusted to minimize losses for the system of multiple windfarms and transmission lines. A loss optimizing algorithm is applied to the combined multiple windfarm and transmission line to shift reactive load among local windfarms to minimize losses and to shift reactive load among individual wind turbines within an individual windfarm.

Abstract: A wind turbine generator control system includes relatively fast regulation of voltage near the individual generators with relatively slower overall reactive power regulation at a substation or wind farm level. The setpoint of the relatively fast voltage regulator is adjusted by the relatively slow reactive power regulator. The fast voltage regulation can be at the generator terminals or at a synthesized remote point.

Abstract: A wind turbine generator control system includes relatively fast regulation of voltage near the individual generators with relatively slower overall reactive power regulation at a substation or wind farm level. The setpoint of the relatively fast voltage regulator is adjusted by the relatively slow reactive power regulator. The fast voltage regulation can be at the generator terminals or at a synthesized remote point.

Abstract: A wind turbine generator control system includes relatively fast regulation of voltage near the individual generators with relatively slower overall reactive power regulation at a substation or wind farm level. The setpoint of the relatively fast voltage regulator is adjusted by the relatively slow reactive power regulator. The fast voltage regulation can be at the generator terminals or at a synthesized remote point.

Abstract: An electrical interconnection system (100) comprises a variable frequency rotary transformer (102) and a control system (104). The control system (104) adjusts an angular position of the rotary transformer (102) so that measured power (P1) transferred from a first electrical system (22) to a second electrical system (24) matches an inputted order power (P0). The rotary transformer (102) comprises a rotor assembly (110) and a stator (112), with the control system (104) adjusting a time integral of rotor speed over time. The control system (104) includes a first control unit (107) and a second control unit (108). The first control unit (107) compares the input order power P0 to the measured power P1 to generate a requested angular velocity signal &ohgr;0.

Abstract: An electrical interconnection system (100) comprises a variable frequency rotary transformer (201) and a control system (104). The control system (104) adjusts an angular position of the rotary transformer (102) so that measured power (P1) transferred from a first electrical system (22) to a second electrical system (24) matches an inputted order power signal (P0). The controller limits the power requested by the power order signal based on measured voltages, e.g., the controller has a power-limit function which overrides the order power signal when a measured power exceeds a limit computed from the measured voltages. The limit function is a fraction of maximum theoretical power.

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.

Abstract: A circuit and method for regulating power supplied on a network which provides power to an electric arc furnace or other highly variable load. The circuit includes at least a first inverter connected in series with the arc furnace transformer, and in shunt with the power supply. The circuit and method provide an effective, low cost technique for controlling network power.

Abstract: An active power line compensation circuit for providing a power distribution network with a series compensation system that utilizes a transformer-coupled three-phase voltage-source inverter. A solid-state thyristor shorting ("crowbar") switch is provided on a third winding of a coupling series transformer. The transformer couples the ac output of a three-phase voltage-source inverter (VSI) to the power distribution network. The crowbar switch circuitry utilizes three diode-thyristor pairs, where each pair is connected to one phase leg of the VSI. The thyristors of the crowbar switch are each controlled by an fault output signal from an overcurrent or overvoltage sensor, that is coupled to a tertiary winding of the transformer. The fault signal closes the thyristors and thereby shunts overcurrent that would otherwise flow through the VSI. When the fault signal ceases, the thyristors automatically switch open when a null current is present in the normal three-phase line current.