Electric Power Research Institute Incorporated

Tennessee Valley Authority

Arshad Mansoor

Jih-Sheng Lai

Arindam Maitra

Frank Goodman

Satish Rajagopalan

William Mack Grady

Doni Joe Nastasi

Dale T Bradshaw

Michael R Ingram

Thomas D Geist

Scott Bunton

Frederic Gorgette

Haresh Kamath

Matthew Robert Rylander

Faisal Habib Khan

This invention relates to a hybrid passive agent system impedance monitoring station and method. The method of monitoring impedance of an electrical system includes the steps of providing an impedance monitoring station adapted to test and monitor system impedance, solving for system impedance in a time domain, solving for system impedance in a frequency domain, and determining a time domain driving point impedance and a frequency domain driving point impedance to identify the impedance of the system.

Passive agent system impedance monitoring station and method

A photovoltaic (PV) integrated variable frequency drive system having a variable frequency drive and an energy source. The variable frequency drive having a back end inverter, a DC bus electrically connected to the back end inverter, and an active front end electrically connected to the DC bus to facilitate bi-directional power flow to and from a power grid. The energy source being electrically connected to the DC bus.

Photovoltaic integrated variable frequency drive

A method and apparatus for automatically monitoring and controlling various parameters of individual ultracapacitor cells in a series string of such cells. These parameters are monitored, and a replacement charge current is delivered to any cell which has lost charge due to discharge either external or internal to the cell. Also, the application of this method and apparatus to energy storage systems for an electrical power transmission grid.

Method and apparatus for managing ultracapacitor energy storage systems for a power transmission system

A multilevel converter-based, intelligent, universal transformer includes back-to-back, interconnected, multi-level converters coupled to a switched inverter circuit via a high-frequency transformer. The input of the universal transformer can be coupled to a high-voltage distribution system and the output of the universal transformer can be coupled to low-voltage applications. The universal transformer is smaller in size than conventional copper-and-iron based transformers, yet provides enhanced power quality performance and increased functionality.

Multilevel converter based intelligent universal transformer

A multifunction hybrid intelligent universal transformer includes a conventional transformer coupled with power electronics on the secondary side to enhance the functionality of power conversion. The universal transformer includes features for overcoming the deficiencies associated with conventional transformers, including voltage sag compensation, instantaneous voltage regulation, outage compensation, capacitor switching protection, harmonic compensation, single-phasing protection, DC output, and variable frequency output.

Multifunction hybrid intelligent universal transformer

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Oak Ridge, TN, United States of America

Arshad Mansoor