Abstract: The invention is for a 3-phase electronic tap changer commutation device to be utilized in electronic regulators, and more particularly to 3-phase alternating current (AC) electronic tap-changing voltage, current or phase correcting regulators. The present invention provides a specific transformer winding topology and commutation technique that improves performance and reduces cost compared to conventional methods.

Abstract: The invention provides a novel 3-phase electronic tap changer commutation and related device. In one embodiment, the invention includes firing a commutation silicon controlled rectifier (SCR), removing a gating signal from a first SCR connected to a first of the plurality of taps, firing a second SCR connected to a second of the plurality of taps, and removing a gating signal from the commutation SCR.

Abstract: The invention is for a 3-phase electronic tap changer commutation device to be utilized in electronic regulators, and more particularly to 3-phase alternating current (AC) electronic tap-changing voltage, current or phase correcting regulators. The present invention provides a specific transformer winding topology and commutation technique that improves performance and reduces cost compared to conventional methods.

Abstract: A voltage regulator is presented for regulating at least one of voltage, current or power to an electrical load. The regulator includes a transformer series connected between a power source and electrical load, and a bypass switch connected in parallel with the series connected transformer. The bypass switch is a back-to-back pair of silicon controlled rectifiers (SCRs). A pulse width modulated (PWM) inverter is coupled to the series connected transformer for generating a voltage to be applied to the series connected transformer. A controller is provided for transitioning the regulator from a normal mode through a commutate mode to an active mode, wherein the bypass switch is active in the normal mode and inactive in the active mode. The inverter provides a voltage to the series connected transformer in the active mode, and the controller and the PWM inverter together are configured to actively force the SCR off when the device is in the commutate mode.

Abstract: A regulator is provided for establishing asymmetrical voltage increase/decrease capability between an input node and an output node for enhanced regulation of either a voltage sag or a voltage swell within a utility system. The regulator includes an autotransformer having an input tap coupled to the input node of the regulator and an output tap coupled to the output node. The regulator further includes an electronic tap changer system coupled to the winding of the autotransformer. Together, the autotransformer and the electronic tap changer system provide the regulator with its asymmetrical voltage increase/decrease capability between the input node and the output node thereof. The regulator can be configured for voltage increase only, voltage decrease only, or both, provided an asymmetrical voltage increase/decrease capability is defined.

Abstract: A device/method for actively interrupting fault current in an ac or dc power system before the fault current is capable of growing to peak magnitude or steady state condition, respectively, is presented. In an ac implementation, a commutating capacitance of desired polarity from one of two commutating circuits is coupled across a circuit interrupter comprising a pair of separable contacts. The circuit interrupter operates to open circuit the power system upon reaching zero current therethrough. The commutating capacitance of appropriate polarity actively drives the fault current to zero before the fault current reach peak magnitude, thereby allowing the circuit interrupter to open circuit the power system before the fault current's natural current zero. In dc implementation, the commutating capacitance is connected to dissipate a fault current while the system is in transient state, thereby protecting the power system from full steady state fault current condition.

Abstract: A tap changing system for operation with a transformer and featuring a special group of gate-controlled electronic devices that operate as a circuit breaker and recloser such that, after half-cycle of short-circuit current, said special group is transferred to the OFF-state, whereby the tap changer winding is open circuited; the advantage being that only the special group of devices need be rated to sustain short-circuit conditions; a further feature is the concept of Discrete-Cycle Modulation (DCM) whereby tap voltage magnitudes are obtainable in increments intermediate the physical tap winding voltage magnitudes.