Provided is an apparatus and method for improving generation efficiency of a distributed generation facility, and more specifically, to an apparatus and method for improving generation efficiency of a distributed generation facility configured to improve generation efficiency by boosting a voltage within an allowable voltage range according to a linkage capacity when the generated power of the distributed generation facility is linked and supplied to a power transmission and distribution side.

A cascading tap changing regulator has a set of input taps to power both stages of the cascade, each stage having its own series injection transformer to regulate the output. A set of switches are selectively engagable in respective on-off modes to effect a number of regulation steps, and a ratio of the number of steps to the number of switches in the set is greater than 1:1.

A system and a method for locally controlling delivery of electrical power along the distribution feeder by measuring certain electricity parameters of a distribution feeder line using a substation phasor measurement unit (PMU) electrically coupled to a substation distribution bus at a first node on the feeder line, and at least one customer site PMU electrically coupled to a low voltage end of a transformer at a customer site, wherein the transformer is coupled by a drop line to a second node on the distribution feeder line and the customer site is coupled by another drop line to the transformer, and by controlling at least one controllable reactive power resource and optionally a real power resource connected to the second node or at the customer site. Related apparatus, systems, articles, and techniques are also described.

A configuration for stabilizing an AC voltage grid has a rotating phase-shifter that is configured to exchange reactive power with the AC voltage grid. The configuration is distinguished by a converter which has a grid side for connection to the AC voltage grid and a machine side for connection to the phase-shifter. A method is furthermore taught for stabilizing the AC voltage grid by way of the configuration.

An auto-transformer rectifier system comprising an 18-pulse (or multiple of 18-pulse) autotransformer rectifier unit ATRU having three, or a multiple of three, diode bridge rectifiers and a balancing resistor to balance the power flow through the diode bridge rectifiers, wherein the balancing resistor has a variable resistance, and further comprising a controller configured to identify imbalances between power flows of the respective diode bridge rectifiers and to adjust the resistance of the balancing resistor in response to the detected imbalance.

A method and apparatus for minimizing circulating currents on a power distribution line. In one embodiment, the method comprises dynamically adjusting a turns ratio of a tap changing transformer, the tap changing transformer coupled to a power grid distribution line that is also coupled to a plurality of microgrid branches wherein at least one microgrid branch of the plurality of microgrid branches comprises a distributed energy resource (DER), based on a reactive power measured locally to the tap changing transformer, to minimize current circulating on the power grid distribution line.

A system and a method for locally controlling delivery of electrical power along the distribution feeder by measuring certain electricity parameters of a distribution feeder line using a substation phasor measurement unit (PMU) electrically coupled to a substation distribution bus at a first node on the feeder line, and at least one customer site PMU electrically coupled to a low voltage end of a transformer at a customer site, wherein the transformer is coupled by a drop line to a second node on the distribution feeder line and the customer site is coupled by another drop line to the transformer, and by controlling at least one controllable reactive power resource and optionally a real power resource connected to the second node or at the customer site. Related apparatus, systems, articles, and techniques are also described.

A method of operating a power generating system for a wind turbine connected to an electrical grid, the power generating system comprising a power generator, a converter, a transformer and a tap changer, the method comprising; monitoring a signal for detecting a voltage in the electrical grid which requires an increase in output voltage from the power generating system; determining a partial-load condition of the converter, which corresponds to the converter being configured to output a voltage which is substantially below its maximum output voltage; and upon determining the partial-load condition, operating the tap changer to tap down the transformer, and operating the converter to provide the required increase in output voltage from the power generating system.

A power supply for a power line includes a synchronization module having a receiver configured for receiving a clock signal from a satellite-based positioning system and an oscillator configured for generating a periodic signal synchronized to the received clock signal. The power supply includes an inverter module having an inverter configured for supplying an AC voltage to the power line, receiving the periodic signal from the synchronization module, and controlling the inverter using the received periodic signal as a synchronization reference signal for the supplied AC voltage. The power supply further includes a power exchange control module configured for: monitoring an active power flow P from the inverter module to the power line, determining whether the active power flow P satisfies a reverse-flow condition, and when the reverse-flow condition is determined, adapting at least one of a phase and an output voltage of the supplied AC voltage.

The present invention relates to an on-load tap changer control method for a power transformer in a power system. The power transformer has a primary side for a connection to a first grid in which electric power is generated, and a secondary side for connection to a second grid in which electrical power is consumed, the power transformer being equipped with an on-load tap changer. The method includes measuring the voltage and current at least on the primary side (u.sub.1, i.sub.1) or on the secondary side (u.sub.2 i.sub.2) of the power transformer, processing said measured voltages (u.sub.1; u.sub.2) and currents (i.sub.1; i.sub.2) in order to derive prospective reactive power at the output of the power transformer after prospective tap-change, comparing prospective reactive power to a predefined set-point, and—initiating tap-change of on-load tap changer if prospective reactive power is closer to said predefined set-point than actual reactive power.