Abstract: The following steps are performed in order to test a tap changer of a transformer which tap changer is designed to change a transmission ratio of the transformer: generating a test signal which is supplied to a winding of the transformer and to the tap changer, repeatedly actuating the tap changer in order to change the transmission ratio with each actuation, determining a curve of an electrical measurement variable (I; I1; I2) of the transformer over time (t) for each actuation of the tap changer depending on the test signal filtering the curves in order to prevent at least one of the curves from being output outputting the filtered curves.

Abstract: The following steps are performed in order to test a tap changer (20) of a transformer (5; 6) which tap changer is designed to change a transmission ratio of the transformer (5; 6): generating a test signal which is supplied to a winding (1-3; 10) of the transformer (5; 6) and to the tap changer (20). Repeatedly actuating the tap changer (20) in order to change the transmission ratio with each actuation. Determining a curve of an electrical measurement variable (I; I1; I2) of the transformer (5; 6) over time (t) respectively during the step of actuating the tap changer (20) depending on the test signal. automatically illustrating the curves (41, 42) in a temporally-superimposed manner.

Abstract: Systems and methods are described herein for managing the operations of a plurality of microgrid modules. A microgrid module includes transformers and/or power converters necessary for modifying the input AC or DC power sources to meet the required characteristics of the output power. The microgrid module further comprises a control software module and a power router software module. The control software module receives data from sensors in the microgrid module and controls the flow of power with controllable elements. The power router software module controls the operation of the power router. The power router can detect changes in demand for power within the microgrid module or from other microgrid modules. The power router can adjust the flow of power between the microgrid modules in response to changes in the supply of power to the microgrid module and changes in the demand for power from the microgrid module.

Abstract: We disclose herein a power coupler for connecting AC or DC electrical circuits having different voltages, current or impedance levels. The power coupler comprise a first switching device; a second switching device coupled with the first switching device; a power transformer comprising a first core winding and a second core winding; a first capacitance coupled between the terminals of the first core winding; a second capacitance coupled between the terminals of the second core winding; and a third capacitance coupled between the first and second cores windings. The power transformer is coupled with the first and second switching devices. The power coupler is configured to reduce switching power loss using an adiabatic technique and by selecting appropriate switching time of the switching devices.

Abstract: An operational setting of an on-load tap changer used to switch between various winding taps of a tapped transformer is determined by first placing the on-load tap changer in operation with the tapped transformer and then moving the changer in a first rotational direction through a regulating range of its stationary operational settings on different winding taps of the tapped transformer toward an end abutment of the tapped transformer. The position is registered on reaching the end abutment of the regulating range of the on-load tap changer, and then the movement is reversed to return to the first stationary operational setting that is then configured as a predefined operational setting with the help of the parameterization that is stored in a nonvolatile memory of the control device.

Abstract: Systems and methods are described herein for controlling the states of a microgrid module. The microgrid module includes transformers and/or power converters necessary for modifying the input AC or DC power sources to meet the required characteristics of the output power. The microgrid module further comprises a control software module installed on a microgrid computer. The control software module receives data associated with the operating state of the microgrid module. The control software module can access rules associated with each microgrid module operating state to determine whether the microgrid module must transition to a different operating state. If a transition is appropriate, the control software module can apply commands to transition the microgrid module to a different operating state. The control software module can continue to monitor the microgrid module to determine when another state transition is appropriate.

Abstract: A smart link in a power delivery system includes an insulator, which electrically isolates a power line, and a switchable conductance placed in parallel with the insulator. The switchable conductance includes switchgear for sourcing, sinking, and/or dispatching real and/or reactive power on the power line to dynamically in response to dynamic loading, transient voltages and/or currents, and phase conditions or other conditions on the power line.

Abstract: A shore power system includes a primary switchgear, a secondary switchgear, a dual output power transformer disposed in electrical communication between the primary switchgear and the secondary switchgear, a grounding switch section, and a vessel connector assembly. The shore power system further includes an automation and control system for automating and/or controlling the delivery of power to the vessel from a source of power, such as a medium voltage power source. In embodiments of the present disclosure, the medium voltage power source may be from the power grid or may be from a discrete power generation station.

Abstract: A multi-phase control system having multi-phase operation with single phase control includes a main control module, a lineman module, and an add-on lineman module. The main control module and the lineman module control, automatically or manually, the first phase and first phase tap changer of a multi-phase system. The add-on lineman module and the main control module control, automatically or manually, additional phases of the multi-phase system. In certain example embodiments, the multi-phase control system detects when a line voltage of an additional phase is de-energized and allows the tap changer of the additional phase to be powered by a line voltage of the first phase. In certain example embodiments, the tap changer of a de-energized phase is powered by an external power supply.

Abstract: A three-phase boost-buck PFC converter including three independent single-phase boost-buck PFC circuits respectively is provided, which are capable of performing PFC on each phase of the three-phase power. The single-phase boost-buck PFC circuit is composed of two single-phase boost-buck converters independently working in a positive and a negative half cycle of an input voltage, and the two single-phase boost-buck converters are connected in parallel at an input side, and are connected in series at an output side, and each of the single-phase boost-buck converters is composed of a front-end boost circuit and a back-end buck circuit connected in cascade. Compared to the existing technique, regardless of a boost mode or a buck mode, the conduction loss is effectively reduced, and the whole system efficiency is effectively improved.

Abstract: AC module makers must prepare two types of AC modules for the 100-V and 200-V outputs only for domestic supply. For foreign countries, the makers must manufacture AC modules compatible with more system voltages. To solve these problems, the control circuit of an AC module controls the operation of an inverter circuit and/or the transformation ratio of a transforming circuit, and ON/OFF-controls a switch on the basis of the system voltage and connection state of an electric power system.

Abstract: System for voltage regulation, control, protection and monitoring of state of changers under power transformer load, voltage regulators, capacitor banks and similar”, is preferably applied to power transformers (1) and voltage regulators and similar, through a microprocessor (2) it provides innovating functions that make up for deficiencies of currently existing voltage relays, highlighting pre-programming, by means of man-machine interface such as, for example, keyboard and display (3), or serial communication (4) of several settings and different voltage regulation parameters, each adequate setting for a certain prevailing load condition, performed by means of dry contact inputs (5), contact outputs (6) destined for self-diagnosis signaling and alarms (7); voltage regulation allows parameter selection to be made by means of daily and hourly programming through an internal clock (8); said system (S) also has the non-volatile memory function (9); CDC blocking function (10) that directly acts on the motorized

Abstract: A load tap changer includes a single mechanical switch that is movable to create, in a first position, a first conducting path between a first transformer tap and a load. When the switch is in a second position, the switch creates a second conducting path between a second transformer tap and the load. A first thyristor pair or other device creates a first alternate conducting path between the first transformer tap and the load when the switch is disengaged from the first position. A second thyristor pair or other device creates a second alternate conducting path between the second transformer tap and the load when the mechanical switch is disengaged from the second position. Each thyristor pair may be selectively triggered to provide a conducting path when voltage across either thyristor pair exceeds a predetermined level. A gate trigger circuit may be included for each thyristor pair, and a gate control circuit may control each of the gate trigger circuits.

Abstract: The invention relates to a multipoint switch for continuously switching different coil branches of a step-down transformer. According to said invention, at least one torque motor associated to various drive configurations carries out different driving functions for individual groups, thereby substituting a conventional motor.

Abstract: A load tap changer (LTC) having a plurality of windings is coupled to one of the primary and secondary windings of a power transformer in order to regulate the output voltage of the power transformer. The LTC includes a plurality of taps physically and electrically connected to the LTC windings and the transformer's output voltage is increased/decreased by moving along the taps a contacting element whose movement is controlled by a rotating shaft driven by a motor. The tap being contacted is determined by sensing the direction and number of shaft rotations and by checking the number of shaft rotations specified to go from a tap to the next tap being contacted. The time for a full rotation of the shaft is also measured. Also, the temperature of the tanks containing the LTC taps and the power transformer is measured for each tap position.

Abstract: A system and method for remotely monitoring load tap changes on utility-type equipment are disclosed. In one example embodiment, a sensor measures a voltage before a tap change and compares the measured voltage to a voltage after the tap change. From this information, the direction of the tap change and the distance traveled can be determined. The system and method can also include a timer to measure an elapsed time required to complete a particular tap change and use this time information to determine the distance traveled. The direction of the tap change can be determined from a sensor that triggers the timer. The system and method thereby enable efficient and cost-effective remote monitoring of load tap changes and positions.

Abstract: An apparatus for selectively stepping up/down the voltage applied from an input to any load in an alternating current power system. The apparatus includes an auto transformer having a series winding with a plurality taps for the selection of different output load voltages and a common winding. The series winding being connected between said input of the alternating current power system and said common winding. The common winding being connected between the series winding and common or neutral terminal of an alternating current power system. The load is being connected between one tap of the series winding and the common or neutral terminal of the alternating current power system.

Abstract: An ANSI Type A voltage regulator that eliminates the need for a potential transformer is disclosed. A control unit finds an output voltage by constantly monitoring the input voltage across the utility windings and the stored tap position. The value of the output voltage is further fine tuned by taking into account the effect of the impedance of the voltage regulator itself on the output voltage. The impedance is calculated using the instantaneous current through the regulator, the maximum rated current of the voltage regulator, the instantaneous voltage through the voltage regulator, the instantaneous Power Factor, and the tap position of the voltage regulator.

Abstract: A method of controlling a step switch. From the measured values of current, voltage and phase angle at an electric drive motor during actuation of the step switch the individual picked-up active output is calculated. From the active output the corresponding torque at the drive motor is calculated. The torque in the step switch which is crucial for controlling is determined on the basis of the torque by using a specifically calculated transfer function. The transfer function is newly determined every time the switch is actuated, with the values of the preceding switch operation or the preceding switch operations being taken as a basis of the new calculation.

Abstract: A method for dynamically determining tap position in a step voltage regulator is disclosed. A present tap position is determined and the value of an applied voltage across a tap changing mechanism is measured. Based upon the value of the applied voltage, a directional change in the tap position is detected. A trigger signal is also generated which is responsive to a detected change in tap position. Finally, a new tap position is calculated based upon the present tap position and the directional change in the tap position, when the trigger signal indicates that a change in tap position has taken place.

Abstract: A method of monitoring a tap changer in which measured values representing the status of the tap change operation are associated with positions of the tap changer and the position range or time range for the tap change is subdivided into partial intervals for which characteristic values of the measurement are calculated by a calculating rule, e.g. averaging. These characteristic values are compared with stored parameter data and operation categories are established which are then used exclusively for the further information processing.

Abstract: Multiple pairs of stationary and moveable contacts are toggled simultaneously between an open and closed position to disconnect or connect a meter from or to a line power source, by a reciprocating operator driven by low power clock motor. The operator is connected to the contacts through a series of pivotally coupled toggle links that are spring biased to maintain the contacts in either of two stable states, open or closed. The disconnect switch is housed as a modular unit that is interposed between the meter socket and the meter. The switch is remotely actuated and cycles the motor through a pre-determined number of degrees of rotation sufficient to change the state of the contacts.

Abstract: A power converter for converting shore power voltage, phase, and frequency for shipboard use includes a variable inductance input transformer that can be connected to the shore power. The primary windings of the transformer have a plurality of taps, and a respective computer-controlled switch is connected between adjacent taps to selectively establish a closed circuit or an open circuit between the taps and thereby configure the primary windings as a low or high voltage "delta" or "wye", as appropriate for the shore power voltage. The output of the input transformer is sent to a variable speed drive, then to an output transformer, and thence to the distribution bus of the ship. A voltage regulator regulates the output voltage of the output transformer. If desired, a phase selector can be provided between the shore power and input transformer to establish the phase characteristics (i.e.

Abstract: A power converter for converting shore power voltage, phase, and frequency for shipboard use includes a variable inductance input transformer that can be connected to the shore power. The primary windings of the transformer have a plurality of taps, and a respective computer-controlled switch is connected between adjacent taps to selectively establish a closed circuit or an open circuit between the taps and thereby configure the primary windings as a low or high voltage "delta" or "wye", as appropriate for the shore power voltage. The output of the input transformer is sent to a variable speed drive, then to an output transformer, and thence to the distribution bus of the ship. A voltage regulator regulates the output voltage of the output transformer. If desired, a phase selector can be provided between the shore power and input transformer to establish the phase characteristics (i.e.

Abstract: An tap changer for a voltage regulator including a tap positionable to vary the winding ratio of the transformer in response to changes in an electric load on the transformer is disclosed herein. The transformer includes a potentiometer mechanically coupled to the tap changer motor and immersed in the coolant of the tap changer, wherein the potentiometer generates a voltage representative of the position of the tap. An analog-to-digital conversion circuit converts the voltage to a digital signal representative thereof, and a microprocessor coupled to the analog-to-digital conversion circuit compares the digital signal to digital data representative of the full voltage range of the potentiometer which is correlated to the actual position of the tap.

Abstract: A tap changer in which a pair of selector contacts can be jointly movable or individually movable to engage stationary tap contacts of an array and one of the selector contacts is in series with a tickler coil and switchover resistor connected to one fixed contact of a bypass switch whose movable contact is connected to the load. The other selector contact is connected to one stationary contact of a switchover switch whose movable contact is connected to a second contact of the bypass switch while another contact of the switchover switch is tied to a point between the tickler coil and the resistor. A pair of oppositely poled parallel thyristors bridges the auxiliary network of the tickler coil and resistor and the main branch passing from the switchover switch to the bypass switch. The movable contacts are operated by an intermittent drive of the Geneva mechanism type.

Abstract: A tap changer including a tap positionable to vary the winding ratio of the transformer in response to changes in an electric load on the transformer is disclosed herein. The transformer includes an electric drive which is responsive to raise or lower signals applied thereto in order to selectively position the tap by the raising or lowering of the tap and thereby raising or lowering the transformer winding ratio. Upon sensing the current of the motor control signals, an up/down counter is incremented or decremented. Accordingly, when a tap change signal is detected, the direction of tap changer movement may be determined, based upon the value of the up/down counter. In this way the tap position is also accurately determined and known.

Abstract: A tap changer including a tap positionable to vary the winding ratio of the transformer in response to changes in an electric load on the transformer is disclosed herein. The transformer includes an electric drive which is electrically powered to selectively position the tap to effect incremental changes of the winding ratio. The transformer includes a monitoring system which monitors the load voltage of the transformer with at least one potential transformer which produces signals which are converted to digital data values stored in a circular data buffer. Each time control signals are applied to the electric drive and a subsequent tap change indication is detected, the first and last data values in the circular buffer are compared, and when the difference between the values exceeds a predetermine limit, the system updates a tap position value which represents the position of the tap.

Abstract: An improved voltage reduction apparatus specifically designed to overcome implementation problems of a prior art voltage reduction apparatus. The present invention is designed to overcome the problem of magnetic field flux induced harmonic distortion and heating associated with the prior art which otherwise substantially detracted from the advantageous implementation thereof. More specifically the present invention, also provides a highly advantageous apparatus for reducing voltage to a load, after first providing a full magnitude of voltage thereto by the use of an autotransformer having a series winding and a common winding disconnectable and connectable to one another by means of a relay or other equivalent switching device. However it also provides a bucking coil winding in parallel with the common winding and wound in bifilar opposed relation thereto.

Abstract: A monitor is provided for use with an AC voltage regulator having a number of taps including a neutral tap and a tap changer capable of activating any of the taps. The voltage regulator receives an input voltage and produces an output voltage and is constructed so that the output voltage bears a relationship to the input voltage that depends on the activated tap. The tap changer is constructed to activate different taps as necessary to maintain the output voltage close to a target level despite fluctuations of the input voltage or load. The monitor apparatus includes a switch responsive to activation of the neutral tap for providing initial activated-tap information and a dead-reckoning computation device responsive to changes of the activated tap for updating the activated-tap information in accordance with changes of the activated tap made after the activation of the reference tap.

Abstract: In a alternating current power distribution system utilizing load tap changing (LTC) transformers having selectively actuable tap selector switches operable in response to an LTC control, system including circuitry for providing remotely adjustable bias voltage for combining with the LTC control voltage to remotely control any change of the center operating level of the band.

Abstract: An electrical control means useful in systems wherein a motor, such as a blower motor for an air handling unit, must be run at different speed levels and wherein low voltage power must simultaneously be supplied to another part of the system such as a condenser unit. The invention combines auto-transformer and transformer technologies into a single motor control unit. Wiring to the auto-transformer portion of the unit is arranged in such manner that it may be readily field changed to accommodate the various line voltage and frequency levels encountered worldwide. Thus, a signle standardized unit allows accurate motor speed control and simultaneous low voltage power supply without motor overheating or instability under various line voltage and frequency conditions encountered throughout the world.

Abstract: A power-factor correction system for reactive power control and concomitant power factor correction adapted to cooperate with a line supplying power at a given line voltage from a power generator to an inductive load via a given path, includes a reactive power compensating device in shunt with the line supplying power, and is adapted to be connected in shunt with the inductive load.

Abstract: A power factor correcting system for compensating a lagging power factor reactance for an electric load plurality fed from at least one pair of incoming service lines, comprising, in combination: capacitors for producing leading reactive power; a series transformer, having primary and secondary winding, the secondary winding being connected in series with affected power lines; a variable transformer fed from the service lines and feeding the primaries of the series transformer; the capacitor instrumentality being fed from the affected incoming power lines with a voltage which varies in magnitude as needed, being the sum of the power line voltage plus/minus the variable series transformer secondary voltage; with the variable transformer through feeding of the primaries of the series transformer causing the required voltage variability in the series transformer secondary and subsequently in the feeding voltage applied to the capacitor; sensing instrumentality to detect presence of lagging reactive power requiri

Abstract: A multi-phase regulating transformer is disclosed having a plurality of windings cooperating with stepping trolleys which are driven by a common driving member. To obtain fine adjustment of the output voltage, the trolleys are coupled to the driving member with different plays to introduce a dead travel of the driving member relative to at least one trolley, which exceeds the spacing between two adjoining individual windings of the transformer.

Abstract: A system for automatically controlling output voltage to correct for varying input voltage utilizes a transformer having a movable core structure. The output voltage from the transformer is sensed and made to conform to a predetermined standard by moving the movable core structure, which is then locked in position after its adjustment. Voltage changes are step-free, and linear voltage control with respect to time is achieved through non-linear movement of the core structure over a range of variation of the output voltage.

Abstract: A turn-on control system for series variable transformer type voltage drop compensators comprising a voltage corrective variable compensating winding in combination with a voltage sensing main control to sense the voltage deviations of the utility's incoming service line with respect to a given reference voltage and a regulating control which operates the variable compensating winding. Upon occurrence of a power brownout the voltage corrective assumes its highest corrective position. Upon blackout the control system actuates the disconnection of the voltage corrective variable compensating winding and regulating control. Upon return of power the voltage corrective variable compensative winding is first placed at its lowest corrective position and the subsequent reconnecting of the voltage corrective control operation is effected.

Abstract: The following specification discloses an electrical power controller that has been specifically directed toward the control of lighting. The invention is directed toward reducing electrical energy consumption of high intensity discharge (HID) lamps and fluorescent lamps. The controller is connected at its input to a power line to light a bank of lamps or other electrical energy consuming devices. The output of the controller to the lamps can effectively be optimized at a substantially lower level, providing a high degree of lighting while effectuating a substantial energy saving. The output is controlled by a variable autotransformer having a drive motor that is in turn controlled by an amplifier comparator circuit. A bidirectional ramp generator provides increases and decreases of voltage in a manner to maintain the lights in their optimum operating condition.

Abstract: A circuit for automatically introducing a component of negative resistance line drop compensation into the control circuitry of a conventional voltage regulator to reduce the regulated voltage level on and, consequently, the load current level in a single phase primary electric distribution circuit during periods of peak load. The subject circuit automatically removes the negative resistance component from the regulator control circuitry during off-peak periods when the energy demand or loading on the distribution circuit is relatively low.

Abstract: An under-load switching device particularly adapted for use with a transformer having voltage taps for voltage regulation and for balancing the phase voltages in a multi-phase AC power system includes a pair of rotary tap selectors connected in parallel to the voltage taps, and a pair of switches for alternately connecting the tap selectors to an AC line, such that load current flows through only one tap selector and an associated switch at a time. A control unit monitors the voltage on the AC line, determines the tap required to be selected to compensate for voltage variations, causes the tap selector which is not carrying load current to select the required tap, and operates the switches at a zero-current point to transfer the AC line to the selected tap.

Abstract: An automatic voltage regulating transformer is provided which incorporates a potential transformer electrically disposed across its series windings, and a set of sensing windings disposed across its shunt windings to provide a voltage sensing network which is responsive to the flow of current both into and out of the transformer. The output of the potential transformer is connected in series with the sensing windings to provide a control voltage which is representative of the voltage across the shunt windings and series windings taken together. In the case of a normal voltage regulating transformer, this control voltage is proportional to the voltage across the output terminals. In the case of an inverted regulating transformer, the output voltage of the voltage sensing network is proportional to the voltage across the input terminals.

Abstract: A circuit for controlling a load tap changing transformer including a true RMS to D.C. converter for regulating the output of the transformer as a function of the RMS voltage.