Schweitzer Engineering Laboratories, Inc.

James Mobley

Raymond W Rice

Shankar V Achanta

Edmund O Schweitzer, Iii

Normann Fischer

Kei Hao

Timothy M Minteer

Eric M Sawyer

David Kenny

Naiden K Spasov

Benjamin T Rowland

Joe Baylon

Johnny J Moore

Ravindra P Mulpuri

Adam Seubert

Sally M Mei

A shunt resistor may, in some cases, receive interference from magnetic fields. The shunt resistor may include a resistive element coupled between multiple conductive elements, and measurement circuitry coupled to the leads, forming an electrically conductive loop. Current through the shunt resistor may be determined by measuring the current through the resistive element at the leads. An induced voltage in the loop may be determined by the product of the loop area and the magnetic field passing through the loop. Consequently, when a magnetic field is passed through the shunt resistor loop, an undesirable interfering signal may be produced, distorting the output signal of the shunt resistor. As the interfering signal is a product of the loop area and the magnetic field, the geometry of the shunt resistor may be modified to reduce the loop area and thus reduce or minimize the interference on the shunt resistor.

Folded current sense shunt resistor

The present disclosure relates to a capacitor bank controller that automatically determines the size of a capacitor bank using wireless current sensors. The capacitor bank controller determines a first capacitor bank size estimate using voltage and current measurements from when the capacitor bank is open and when the capacitor bank is closed a first time. The capacitor bank controller determines a second capacitor bank size estimate by using voltage measurements and current measurements from when the capacitor bank is open and when the capacitor bank is closed a second time. The capacitor bank controller determines a filtered capacitor bank size estimate based on the first capacitor bank estimate and the second capacitor bank estimate and controls operation of the capacitor bank based on the filtered capacitor bank size estimate.

Automatically determining the size of a capacitor bank using wireless current sensors (WCS)

The present disclosure pertains to systems and methods for measuring electrical parameters in an electric power system. In one embodiment, a system may include a line-mounted wireless current sensor comprising a current monitoring subsystem to generate a current measurement of an alternating current flow through an electrical conductor. The line-mounted wireless current sensor may harvest power from the electrical conductor. A processing subsystem may generate a message comprising the current measurement, and the message may be transmitted at a synchronization point using a wireless communication subsystem. An intelligent electronic device (IED) may receive the message. The IED may further generate a voltage and generate a phasor based on the current measurement and the voltage measurement. A control action subsystem may implement a control action (e.g., selectively connecting or disconnecting a capacitor bank) based on the phasor.

Wireless current sensor

The present disclosure pertains to detection of a broken conductor in an electric power system. In one embodiment, a broken conductor detector may be configured to be mounted to an electrical conductor and may comprise a communication subsystem configured to transmit a signal configured to indicate that the conductor is broken. A sensor may determine a plurality of vectors. A processing subsystem may be configured to receive the plurality of vectors from the sensor and to identify when the vector is outside of a range defined by a threshold value. The processing subsystem may determine that the conductor is falling based on the plurality of vectors remaining outside of the threshold for a period of time determined by the timer subsystem. A signal may be transmitted by the communication subsystem to indicate that the conductor is falling.

Broken conductor detector

The present disclosure relates to spectral analysis in wireless current sensors. For example, a wireless current sensor (WCS) includes current transformer windings that harvest electrical energy from a power line and allow the WCS to obtain current measurements of the power line. The WCS includes a processor that obtains the current measurements of the power line via the current transformer windings. The processor generates a frequency domain representation of the current on the power line using the current measurements. The processor sends a wireless signal indicating results from the frequency domain representation to an intelligent electronic device (IED) that monitors the power line to allow the TED to analyze the results for anomalies.

Spectral analysis using wireless current sensors

The present disclosure pertains to a line-powered current measurement system to mount to an electrical conductor and related methods. In one embodiment, a system may comprise a current transformer to electrically couple to an electrical conductor and to generate a secondary current proportional to a primary current in the conductor. A power harvesting subsystem may harvest power from the secondary current in a first configuration. A switching subsystem may transition the line-powered current measurement device between the first configuration and a second configuration, in which a current measurement subsystem generates a measurement of the secondary current. The switching subsystem may provide the secondary current to the power harvesting subsystem in the first configuration and may bypasses the power harvesting subsystem in the second configuration. A communication subsystem may transmit the measurement of the secondary current to a receiver device.

Line-powered current measurement device

The present disclosure relates to powering distributed sensors used to monitor electrical and/or environmental conditions and to powering other equipment associated with electric power systems. In one embodiment, a system may be used to mount a sensor in proximity to a reference conductor. An electric field power conversion subsystem may generate a usable electric potential from an electric field created by the electric power system and existing between the reference conductor and another conductor (e.g., another phase conductor, a ground conductor). The sensor powered by the usable electric potential may provide a measurement of a condition associated with the electric power system. A communication subsystem powered by the usable electric potential may communicate the measurement of the condition to a monitoring system.

Electric field powered devices in electric power systems

The present disclosure pertains to systems and methods for monitoring and protecting an electric power system. In one embodiment, a system may comprise line-mounted wireless current transformers to measure at least one parameter of an alternating current (AC), receive a synchronization signal at which to measure the AC, and send a message comprising the measured AC. The system may also comprise an intelligent electronic device (IED) to send the synchronization signal to and receive the messages from the line-mount wireless current transformers, determine whether a high-impedance fault (HiZ) exists between the line-mounted wireless current transformers, and implement a control action based on the existence of the HiZ fault.

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Moscow, ID, United States of America

James Mobley