Mcgraw-edison Company

Tennessee Valley Public Power Association

Thomas G Dolnik

Clyde Gilker

Michael Peter Dunk

James R Hurley

Naresh K Nohria

James A Jindrick

Norbert J Reis

James A Baranowski

Thomas J Bray

Dennis Alan Walder

Mark A Berezinski

Ross S Daharsh

A control system is used in an intelligent power distribution network. The power distribution network includes multiple branches, each of which is connected to a power source, electrical devices connected to the branches, and a normally-open device connected between two or more branches. The control system includes control elements, each control elements being associated with an electrical device connected to a branch of the distribution network. The control system also includes a master control element associated with the normally-open device. The master control element communicates with the control elements and, when a fault occurs on the distribution network, prevents the normally-open device from closing when information from the control elements indicate that conditions potentially disruptive to the distribution network would occur if the normally-open device were closed. The master control element permitts the normally-open device to close when information from the control elements indicate that conditions potentially disruptive to the distribution network would be avoided if the normally-open device were closed.

Intelligent power distribution network

Apparatus is disclosed for monitoring an A.C. distribution line comprising a novel split transformer core which may be inserted remotely about a distribution feeder line without de-energizing of that line, an encoder for producing a train of voltage signals whose duration are characteristic of the magnitude of the A.C. current flowing through the line and for producing a train of light pulses from the voltage levels which characterize the magnitude of the A.C. current flowing through the line, a decoder which is opticlaly linked to the encoder for measuring the time intervals of the light pulses and for converting the time intervals into a numerical value representing the current flowing through the line.

Current measuring apparatus

A microprocessor based recloser control has a microcomputer for causing trip and close operations of a recloser in response to the conditions of the power distribution lines being protected and operator commands. The microcomputer may be overridden by a mechanical switch in the recloser control. If power to the recloser control is lost, the microprocessor will continue to function with power storage means for a limited duration. Towards the end of that duration, this microcomputer will power down the microprocessor in an orderly manner allowing automatic return to its functions when power is restored. After the microprocessor is no longer functioning, a secondary overcurrent trip circuit is relied upon to cause a trip operation of the recloser for extended durations of power outage. The secondary overcurrent trip circuit can be disabled by the microprocessor. The microcomputer includes means to normalize the input signals from the power distribution lines and multiple redundancy features to prevent undesired operations of the recloser. The recloser control functions in response to the mean square of the currents in the protected power distribution lines, and includes means for protecting its more sensitive components from input signals normally encountered.

Microprocessor based recloser control

A voltage regulating transformer utilizing a microprocessor and a versatile multipurpose set of hardware modules and software modules it is described. A standard tap changing mechanism is driven in response to an analog control signal to change the output voltage of the transformer in response to digitally sampled values of voltage and current which have been transformed from the time domain to the frequency domain through a software program using Fourier transform techniques. The output current is also transformed and digitally processed to determine the power factor and the direction of power flow through the transformer. By inserting the digital values of the line characteristics to the load, line drop compensation is provided for. The difference in voltage across the input and output transformers is transformed to a digital signal and internally processed to provide an indication of the position of the tap changing mechanism without relying upon mechanical devices. The various software and hardware modules are designed so as to be readily utilizable in other electrical distribution controls.

Microprocessor controlled voltage regulating transformer

Growing community of inventors

Kenosha, WI, United States of America

Thomas G Dolnik