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.

An apparatus for a load tap changer includes a first primary winding electrically connected to a first contact, the first contact configured to connect to one of a plurality of taps in a load tap changer; a second contact, the second contact configured to connect to one of the plurality of taps in the load tap changer; a magnetic core; and a control circuit including: a secondary winding configured to magnetically couple to the first primary winding and the magnetic core; and an electrical network electrically connected to the secondary winding, the electrical network being configured to prevent magnetic saturation of the magnetic core during switching of the first or second contact.

A phase shifting transformer for poly-phase alternating current includes source side terminals, load side terminals, an exciting unit, and a series unit. The exciting unit includes further coils that are magnetically coupled to primary coils and to the secondary coils of the exciting unit to provide further voltages. The further coils are connected in series between the source side terminals and the series unit, so that the voltages at the load terminals are combinations of the quadrature voltages and the further voltages with the source voltages, thus modifying the voltage phase displacement between the source side terminals and the load side terminals.

A voltage reactive power control device includes a bus voltage fluctuation extracting unit that extracts a bus voltage fluctuation from a voltage of a secondary-side bus, an RE component extracting unit that extracts a fluctuation component due to renewable energy power generation from the bus voltage fluctuation, a creating unit that creates a reactive power command value for suppressing the fluctuation component based on the bus voltage fluctuation component due to the renewable energy power generation extracted by the RE component extracting unit, and a control unit that executes the reactive power control on a battery system based on the reactive power command value. The RE component extracting unit extracts the fluctuation component due to the renewable energy power generation by eliminating the fluctuation components other than the fluctuation component due to the renewable energy power generation from the bus voltage fluctuation.

A method of preventing disjunctions in a power distribution unit having a plurality of output connectors is disclosed. A power level of each of the output connectors is sensed. It is detected that the power level of a given output connector exceeds a fixed power limit. In response to the detection, a delivery of power by the given output connector is stopped while maintaining a delivery of power by a remainder of the output connectors. Power delivery may be resumed in response to receiving a user command to rearm the given output connector. A power distribution unit adapted to prevent disjunctions is also disclosed.

A circuit comprises an output connector connectable to a load. A relay selectively connects the output connector to an AC power source. The relay is responsive to a disabling signal to disconnect the output connector from the AC power source. A sensor senses a level of power delivered to the load via the output connector. A detector emits a first fault signal when the sensed power level exceeds a fixed power limit. A latch maintains the first fault signal until it receives a rearm signal. A controller emits a second fault signal when the sensed power level exceeds a configurable power threshold, receives a user command to rearm the circuit, and in response to receiving the user command, emits the rearm signal and ceases the emission of the second fault signal. A logic combiner generates the disabling signal when it receives one of the first and second fault signals.

A method of limiting a total power delivered by a power distribution unit having a plurality of output connectors is disclosed. A configurable power threshold is assigned for each of the output connectors so that a sum of the configurable power thresholds of the output connectors does not exceed a maximum rated power for the power distribution unit. A power level of a given output connector is sensed. A delivery of power by the given output connector is stopped when the power level of the given output connector exceeds the configurable power threshold for the given output connector. Power delivery may be resumed in response to receiving a user command to rearm the given output connector. A power distribution unit adapted to limit its total power delivery is also disclosed.

A centralized voltage controller according to the present invention includes a voltage distribution determination unit that calculates a controlled amount in each of a plurality of voltage controllers on the basis of a measured value of a voltage at each point on a distribution line, a tap position determination unit that determines a change amount of a tap position to be given to each of a plurality of local voltage control units on the basis of the controlled amount, and a tap-change-amount management unit that limits the change amount when receiving, from the local voltage control unit, a limit signal indicating that a tap position in the voltage controller controlled by the local voltage control unit is an upper limit or a lower limit of a settable range.

The invention relates to a method for controlling a wind turbine configured with an on load tap changer transformer which enables adjustment of a current ratio of a primary side current of the transformer and a secondary side current of the transformer. The method comprises detecting that a network voltage on the primary side or secondary side of the transformer is outside a pre-determined voltage range, and in response determining a current reference for the primary side current based on the detected network voltage. The power converter of the wind turbine is controlled to generate an increase of the primary side current towards the current reference, and the current ratio of the transformer is adjusted towards a higher ratio of the current ratio.

Embodiments of the present disclosure can include a hybrid transformer system comprising an electrical voltage transformer comprising: a high-voltage winding, the high-voltage winding comprising a first end and a second end, the first end having a lower voltage than the second end; a plurality of taps disposed proximate the first end of the high-voltage winding; a multi-level converter coupleable to the plurality of taps of the electrical voltage transformer, the multi-level converter configured to simultaneously control voltage injection and VAR injection to the high-voltage winding of the electrical voltage transformer; and a controller electrically coupleable to the multi-level converter, such that when the multi-level converter is coupled to the plurality of taps of the electrical voltage transformer, the controller is configured to selectively inject at least one of VARs or voltage to the high-voltage winding of the electrical voltage transformer.