A method for controlling voltage in a feeder of a distribution system having a plurality of DERs includes executing a feedback control using an integral controller. A voltage signal is generated using measured or estimated voltages at multiple locations along the feeder. An error is determined between the voltage signal and a defined voltage limit. The error is input to a controller including an integrator to generate a control action to counteract the error. The control action is distributed among at least some controllable DERs, from the plurality of DERs, that are capable of responding to the control action by generating actuation signals for absorbing reactive power from or injecting reactive power into the feeder, and/or for reducing active power or increasing active power in the feeder. The control action continues to increase until the voltage signal reaches the defined voltage limit, to thereby control voltage in the feeder.

An intelligent transformer monitoring system to detect and monitor random failures in distribution transformers due to improper usage and poor maintenance is provided. The intelligent transformer monitoring system includes a GSM-GPRS, a measurement and instrumentation module, a control relay module, a Trivector energy measurement, and a GPS module. The GSM-GPRS includes microcontroller along with GSM_GPRS modem in order to execute remote communication on GSM-GPRS. The Measurement and Instrumentation module includes eleven temperature measurement channels with 8-digital temperature sensors and 3-RTD. The control relay module includes 4 SPDT relays to execute output controls such as load trip and cooling motor etc. The GPS module acquires the latitude, longitude and time data from the satellite for location sharing. The Power supply module is an AC/DC SMPS power supply to convert 240V/415V AC to 12 VDC for the intelligent transformer monitoring system.

A control system for controlling the operation of a doubly fed induction generator of an electrical power system, such as a wind turbine, is provided. A rotor side converter coupled to a rotor of the DFIG is controlled by the control system. The control system includes an outer controller to generate a reference value for a control variable in accordance with which the operation of the DFIG is to be controlled and an inner controller that receives the reference value and provides feedback control of the rotor side converter. The inner controller is a state feedback controller obtains at least one state of the power system or the power grid that is different from the control variable. The control structure of the state feedback controller causes the electrical power system to act as a passive system at least in a predefined frequency range.

Provided are hybrid passive power filter and a three-phase power system. The hybrid passive power filter includes: a series passive harmonic isolation unit, a parallel passive filtering unit, and a harmonic load; the series passive harmonic isolation unit has an input terminal electrically connected to a power grid and an output terminal electrically connected to a first terminal of the harmonic load, and the series passive harmonic isolation unit is configured to isolate harmonics; and the parallel passive filtering unit has an input terminal electrically connected to the output terminal of the series passive harmonic isolation unit and an output terminal electrically connected to a second terminal of the harmonic load, and the parallel passive filtering unit is configured to filter out harmonics.

A device for extinction angle control of a high voltage direct current (HVDC) system, includes: a converter reactive power calculator calculating a reactive power variation amount of a converter included in the HVDC system, depending on firing angle control of the converter; an alternating current (AC) system short circuit level calculator calculating a short circuit level of an AC system by applying the reactive power variation amount to a short circuit level formula of the AC system connected to the HVDC system; an extinction angle variation value calculator calculating an extinction angle variation value of the converter, corresponding to the short circuit level; and an extinction angle controller controlling an extinction angle of the converter, depending on an extinction angle control value reflecting the extinction angle variation value.

A containerized power flow control system is described, for attachment to a power transmission line or substation. The system includes at least one container that is transportable by road, rail, sea or air. A plurality of identical impedance injection modules is operable while mounted in the container, wherein each of the modules is configurable to inject a pre-determined power control waveform into the power line.

A starting and stopping method for a static synchronous series compensator (SSSC) is provided. A starting process includes: connecting a converter to a shunt transformer, and closing a breaker which connect the AC system and the shunt transformer to charge the converter until the DC voltage is stable; opening the breaker, and connecting the converter to a series transformer through a change-over switch; and deblocking the converter, and controlling a current of a bypass switch of the series transformer to approach zero. A stopping process includes: switching a control mode of the converter to make the current of the bypass switch approaches zero when closed the bypass switch, then controlling a current of the series transformer to be gradually reduced to zero to make the series transformer out of service, and blocking the converter.

A switching module may include a plurality of cooling plates stacked along a vertical direction, a switch disposed between the cooling plates, a first supporting member disposed below the lowermost cooling plate, a second supporting member disposed above the uppermost cooling plate, first and second pressing support portions disposed between the lowermost cooling plate and the first supporting member, and a pressing member disposed between the uppermost cooling plate and the second supporting member.

Each of the first and second switching modules may include first through (n+1)th cooling plates stacked along a vertical direction with respect to the support module; first through nth switches respectively disposed between the first through (n+1)th cooling plates; a first electrode plate disposed on the (n+1)th cooling plate; a first supporting member disposed on the first electrode plate; a first pressing member disposed between the first electrode plate and the first supporting member; a second electrode plate disposed below the first cooling plate; a second supporting member disposed below the second electrode plate; and a second pressing member disposed between the second electrode plate and the second supporting member.

Active impedance-injection module enabled for distributed power flow control of high-voltage (HV) transmission lines is disclosed. The module uses transformers with multi-turn primary windings, series-connected to high-voltage power lines, to dynamically control power flow on those power lines. The insertion of the transformer multi-turn primary is by cutting the line and splicing the two ends of the winding to the ends of the cut high-voltage transmission line. The secondary winding of the transformer is connected to a control circuit and a converter/inverter circuit that is able to generate inductive and capacitive impedance based on the status of the transmission line. The module operates by extracting power from the HV transmission line with the module floating at the HV transmission-line potential. High-voltage insulators are typically used to suspend the module from transmission towers, or intermediate support structures. It may also be directly suspended from the HV transmission line.