Abstract: 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.

Abstract: Self-test circuitry for testing a circuit interrupter includes an active element coupled to an operating mechanism, a first sub-circuit for temporarily disabling the active element, a second sub-circuit structured to generate a simulated ground fault condition, and a processing unit coupled to the ground fault detection circuitry. The first sub-circuit and the second sub-circuit, the processing unit being structured and configured to control the first sub-circuit to temporarily disable the active element and to control the second sub-circuit to generate the simulated ground fault condition when the active element is disabled. Also, self-test circuitry that includes a sub-circuit structured to generate a simulated ground fault condition and a processing unit structured and configured to control the sub-circuit to generate the simulated ground fault condition only during a predetermined portion of a half cycle of energy passing through the circuit interrupter.

Abstract: A transformer winding and a dry-transformer are disclosed, which include a main transformer winding, and a supplementary transformer winding configured to be electrically connected in series with the main transformer winding. The supplementary transformer winding can include a first winding module, a second winding module, and a third winding module, each of the winding modules having at least a first, a second and a third winding segment, and wherein each of the winding segments has a tap. A changer is configured to be connected to the taps of the second winding module, and wherein the second winding module is configured to be electrically connected in series to at least one winding segment of the first winding module and the third winding module.

Abstract: A method of operating a device connected to an electric power line conductor includes the steps of attaching a device to a first electric power line conductor, sensing a current in the first electric power line conductor and selecting between a first set of windings and a second set of windings connected in series with the first electric power line conductor.

Abstract: An apparatus and method for measuring the source-side line voltage from a source potential transformer (PT) of a regulator during reverse power flow. A reverse power regulation algorithm is employed during reverse power operation of the tapchanger to energize a contact relay which switches the analog voltage input from the load side to the source side of the regulator. Voltage regulation then operates based on the measured source side voltage instead of the traditional calculation of the source side voltage based upon the load-side voltage and regulator type.

Abstract: A voltage regulator (10) for regulating a power distribution system voltage during forward or reverse power flow. The voltage regulator (10) accommodates multiple configurations of a tertiary winding (30) and a potential transformer (36) connected across source-side bushings (S/SL) or load-side bushings (L/SL). The invention simulates operation of a potential transformer (36), and the output voltage therefrom, connected across the source-side (S/SL) or load-side bushings (L/SL). The invention also produces a corrected voltage compensating a non-standard turns ratio of the tertiary winding (30). The regulator (10) controls a tap changer (18) to regulate the system voltage according to a digital value representing the voltage across the source-side (S/SL) or load-side bushings (L/SL), comprising a measured voltage, the corrected voltage or the simulated voltage.

Abstract: A load tap changer (LTC) having a plurality of windings is coupled to one of the primary and secondary of a power transformer in order to regulate the output voltage of the transformer. The LTC includes a plurality of taps physically and electrically connected to and along the windings and a contacting element is selectively moved along the taps to increase or decrease the output voltage of the transformer. The power transformer and the LTC windings are placed in a main tank and the taps are placed in an LTC tank. The temperature in the main tank and the temperature in the LTC tank are monitored by means of first and second temperature probes whose outputs are used to sense the temperature differential (TDIFF) between the main tank and the LTC tank and to determine if the LTC tank temperature exceeds the main tank temperature for a period of time exceeding a specified time period. Also included is circuitry for sensing the rate of change of TDIFF and determining if it exceeds a predetermined value.

Abstract: A power regulation system is coupled to an AC power source outputting an input voltage. The system has a first transformer to receive the input voltage and generate a control voltage. The system also has a second transformer that has a primary coil and a secondary coil. The primary coil and secondary coil of the second transformer are electromagnetically coupled to each other and so arranged that when the control voltage from the first transformer is applied to the primary coil, an output voltage is generated between a first end and a second end of the secondary coil, wherein the output voltage is substantially 180° out of phase from the input voltage so as to generate an effective voltage applied to the load, and wherein the effective voltage is less than the input voltage and substantially equals to the difference between the input voltage and the output voltage, resulting a reduction in power consumption of the load.

Abstract: A power regulation system is coupled to an AC power source outputting an input voltage. The system has a first transformer to receive the input voltage and generate a control voltage. The system also has a second transformer that has a primary coil and a secondary coil. The primary coil and secondary coil of the second transformer are electromagnetically coupled to each other and so arranged that when the control voltage from the first transformer is applied to the primary coil, an output voltage is generated between a first end and a second end of the secondary coil, wherein the output voltage is substantially 180° out of phase from the input voltage so as to generate an effective voltage applied to the load, and wherein the effective voltage is less than the input voltage and substantially equals to the difference between the input voltage and the output voltage, resulting a reduction in power consumption of the load.

Abstract: A method and apparatus for controlling power transferred and regulating voltage in a multi-phase transmission line includes generating a first plurality of voltages, a second plurality of voltages displaced in phase from the first plurality of voltages, and a third plurality of voltages displaced in phase from the first and second plurality of voltages. The first, second and third plurality of voltages are selectively connected in series in each line of the multi-phase transmission line.

Abstract: A method for regulating the voltage at which electric energy is supplied at the delivery points in a network for distributing electricity. The voltage of electric energy supplied through a high-voltage network is reduced to a voltage suitable for a medium-voltage network by means of at least one variable transformer. The voltage of the electric energy in the medium-voltage network is reduced, by means of at least one transformer, to a voltage suitable for a low-voltage network supplying the electric energy to the consumers. The adjustment of the variable transformer between a high-voltage network and a medium-voltage network is influenced by the actual voltage measured and the current or load at the output side of the variable transformer. The voltage prevailing at the delivery point is measured at the location of at least a number of consumers and the variable transformer is set partly in dependence on the voltage thus measured at the consumers' location.

Abstract: A load is supplied by a transformer supplied via a voltage regulator and thyristor network. The thyristor network and regulator are simultaneously controlled to respond to changes in the load and in practice the thryistors respond rapidly and are re-adjusted as the regulator is inherently more slowly adjusted. The result is that the thyristors produce minimum reflected harmonics overall in the mains and an optimum power factor can be achieved for each power setting.

Abstract: A feed forward AC voltage regulator utilizes a step-up, step-down transformer to apply adjustment voltages to an unregulated AC line. Analog circuitry periodically samples the unregulated AC line input and compares it with a scaled representation of the desired line voltage. Digital circuitry converts the information from the analog sampling and comparison to an instruction command which activates an appropriate solid state switch associated with a tap on a multitap transformer connected to the regulated AC output line. The taps are successively located on the multitap transformer to provide selectable adjustment voltages of various values. The switched-in adjustment voltage is provided the proper polarity and applied to the primary of the step-up, step-down transformer, thereby applying to the secondary the adjustment voltage needed to move the regulated AC output line to the desired level.