Abb Power Td & Company

Vinod N Bapat

John G Reckleff

Per A Danfors

A low cost voltage disturbance mitigation system is capable of providing continuous power to a load despite short interruptions or sag disturbances of the utility power. The interruption and sag mitigation system makes use of a combination of unique thermal and electrical properties of magnetic components, power semiconductor devices, and high-discharge-rate energy storage devices. It also facilitates a modular solution that can be easily and economically scaled up or down for use over a wide range of voltage and power levels, e.g., 480 V to 36 kV and 500 kVA to 10,000 kVA.

System for mitigating voltage disturbances and interruptions for power distribution applications

A solid state voltage regulator and methods therefore are shown to include a transformer having a secondary coil, the secondary coil having a plurality of taps. A first solid state switch is connected between the regulator output and a first tap. The first switch need only have the capability of being turned on in response to a gate signal. A second solid state switch is connected between the regulator output and a second tap. The second switch has the capability of being turned on and turned off in response to gating signals. The output voltage resulting from the second tap is greater than the first tap. A controller, connected to the input, the output, the first switch and the second switch, senses the voltage present at the regulator input and output and generates gating signals in response to the sensed voltage. The voltage regulator may include several switches similar in construction and operation to the first switch. In such a regulator, the second switch is connected to the tap which results in the coil turn ratio yielding the greatest voltage compensation.

Apparatus and methods for minimizing over voltage in a voltage regulator

Methods and apparatus for switching a load between first and second sources is shown to include first and second solid state switches connected to the load. First and second mechanical breakers are connected between the switches and the sources so that each source is connected to the load through a circuit breaker and solid state switch. A controller is connected to sense the voltage from the first and second sources. The controller is connected to the first and second switches and the first and second mechanical breakers. The controller senses the phase difference between the voltages from the first and second sources. The controller causes the first and second mechanical breakers to open and close in response to sensing the phase difference between the sources. The first and second mechanical breakers can include medium voltage vacuum breakers. In a preferred embodiment, when the controller senses that the phase difference between sources is more than 30 degrees out of phase, the controller will open the circuit breaker connected to the alternate source. In this manner voltage stress on the solid state switching devices is minimized.

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Raleigh, NC, United States of America

Vinod N Bapat