Schweitzer Engineering Laboratories, Inc.

Google Inc.

Kei Hao

Shankar V Achanta

Raymond W Rice

Jeremy William Blair

Armando Guzman-Casillas

James Mobley

Mark W Feltis

Naiden K Spasov

David Keckalo

Hammad Ahmad Khan

Naresh Malla

Generally disclosed herein is a power system architecture for controlling self-healing operations for N number of feeder units. The power system architecture may restore power automatically to all feeder units when a loss of power occurs by reconfiguring the status of feeder unit breakers. The power system architecture may also reconfigure and restore power automatically by opening and closing feeder unit breakers when a loss of source returns. The power system architecture may further reconfigure and restore power automatically for as many feeder units as possible under abnormal conditions such as fault scenarios, breaker failures, operation failures, and relay failures.

Controlling feeder units for self-restoration of power

Methods and devices are provided for determining the number of open phases and which particular phases may be open in capacitor bank system. Detecting open phases may include determining a neutral current of the capacitor bank system. According to one detection method, in response to a magnitude of the neutral current being greater than a threshold value, an IED may calculate an aggregate power phasor for the phases of the capacitor bank system with respect to each rotation. According to another detection method, in response to the magnitude of the neutral current being greater than a threshold value, an IED may calculate an individual power phasor for each of the phases of the capacitor bank system with respect to each rotation. Based on the magnitude and angles of the power phases, the IED may determine the presence of open phases and which particular phases may be open, respectively.

Systems and methods to identify open phases of a capacitor bank

Systems, methods, and devices are provided for controlling part of an electric power distribution system using an intelligent electronic device that may rely on communication from wireless electrical measurement devices. Wireless electrical measurement devices associated with different phases of power on an electric power distribution system may send wireless messages containing electrical measurements for respective phases to an intelligent electronic device. When wireless communication with one of the wireless electrical measurement devices becomes inconsistent or lost, the intelligent electronic device may synthesize the electrical measurements of the missing phase using electrical measurements of remaining phases. The intelligent electronic device may use the synthesized electrical measurements to control part of the electric power distribution system.

Intelligent electronic device control using wirelessly transmitted multi-phase electrical measurements

The present disclosure relates to a wireless neutral current sensor (WNCS) for monitoring a neutral cable of a capacitor bank. The WNCS may include a power storage device that provides power to allow the WNCS to send a test signal to a capacitor bank controller (CBC) of the capacitor bank to confirm operation of the WNCS during commissioning. The WNCS may include processing and communication circuitry that, during operation, detects an electrical characteristic on the neutral cable. The processing and communication circuitry may provide a message indicating the electrical characteristic to the CBC.

Wireless neutral current sensor (WNCS)

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)

Improvements in the functioning of a line-mounted device to calculate a direction to a fault during current transformer (CT) saturation are disclosed herein. The line-mounted device may determine a load direction using voltage and current zero-crossings and a power system frequency before the fault condition. The line-mounted device may determine a fault direction in relation to the direction to the load after calculating and removing direct current (DC) components of a sampled current signal using valid sample pairs obtained during unsaturated regions of peaks of the sampled current signal. The line-mounted device may indicate the direction to the fault. A system of line-mounted devices may be used to determine a faulted section of a power system using indications of fault direction.

Fault direction calculation during current transformer saturation

A capacitor bank controller may obtain voltage and current measurements while the capacitor bank is disconnected from the power line. Further, the capacitor bank controller may obtain voltage and current measurements while the capacitor bank is connected to the power line. The capacitor bank controller may determine the size of the capacitor bank based on impedances from the voltage and current measurements while the capacitor bank is connected and disconnected.

Determining the size of a capacitor bank

Disclosed herein are systems and methods for safe electric power delivery protection within a high-risk area while maintaining electric power availability in non-faulted areas. Fault signals from wireless sensors are used at a recloser to block reclosing onto a faulted high-risk zone. Fault signals from wireless sensors are used at a recloser to permit reclosing when the reclosing operation will not close onto a fault location within the high-risk zone. Portions of the power system may be selectively openable by sectionalizers. When a fault is reported by a wireless sensor as being on a portion of the power system selectively openable, a recloser may be permitted to attempt a reclose operation affecting the high-risk zone and the selectively openable portion.

Electric power distribution sectionalizing in high-risk areas using wireless fault sensors

Systems and methods to detect that a protective device is operating outside of a time inverse overcurrent tolerance region are described. For example, a central monitoring station may obtain a time inverse overcurrent tolerance region of a protective device on a power line. The central monitoring station may obtain a fault magnitude measurement and a fault duration measurement of a wireless line sensor on the power line. The central monitoring station may determine that the protective device is operating outside of the tolerance region based at least in part on the fault magnitude measurement and the fault duration measurement. The central monitoring station may provide a signal indicating that there is a potential issue with the protective device.

Predictive maintenance of protective devices using wireless line sensors and systems

Systems and methods for calculating load direction even under adverse environmental conditions are provided. A system may include sensing circuitry and processing circuitry. The sensing circuitry may sense a first parameter and a second parameter of the electrical waveform on the transmission line of the electric power distribution system. The processing circuitry may determine a present load direction of an electrical waveform using a first method based at least in part on the first parameter in response to detecting that the sensing circuitry is experiencing a first environmental condition. The processing circuitry may determine the present load direction of the electrical waveform using a second method based at least in part on the second parameter and not the first parameter in response to detecting that the sensing circuitry is experiencing a second environmental condition.

Systems and methods for determining load direction under adverse environmental conditions

The present disclosure relates to a capacitor bank control system that uses a combination of line post sensors and wireless current sensors for control operations. For example, a capacitor bank controller may include one or more inputs that electrically couple to a line post sensor to allow the capacitor bank controller to obtain line post sensor measurements. The capacitor bank controller may include a transceiver that receives wireless current sensor measurements from first and second wireless current sensors. The capacitor bank controller may include a processor that controls one or more switching devices of a capacitor bank based at least in part on a combination of line post sensor measurements and wireless current sensor measurements.

Multi-phase sensing and control using a combination of line post sensors and wireless current sensors

Line-mounted devices for determining fault magnitude in an electric power delivery system even under current-transformer (CT) saturation are disclosed herein. Fault magnitude is calculated using unsaturated regions of a current waveform captured by the line-mounted device. The method of determining the unsaturated regions is computationally efficient. Fictitious peaks are removed, and the unsaturated regions are determined based on fractions of the valid peaks. Fault current magnitude is calculated using sample values in the unsaturated regions.

Fault current calculation during transformer saturation using the waveform unsaturated region

The present disclosure relates to controlling a capacitor bank using current measurements from different current sensors depending on the power flow direction. For example, the system may perform capacitor bank control operations using current measurements from a first current sensor coupled to the power line between an initial source and the capacitor bank when power is flowing in a first power flow direction on the power line. The system may determine that power flow on the power line has changed from flowing in the first power flow direction to flowing in a second power flow direction from an updated source, different from the initial source. The system may, upon detecting the change in the power flow direction perform control operations of the capacitor bank using current measurements from a second current sensor between an updated source and the capacitor bank.

Bidirectional capacitor bank control

A system is provided for monitoring and protecting an electric power distribution system using intelligent electronic devices that may rely on the communication from wireless electrical measurement devices. A wireless electrical measurement device may obtain electrical measurements on a transmission line and wirelessly transmit messages containing the measurements to an intelligent electronic device. The intelligent electronic device may determine a consistency of wireless communication from the wireless electrical measurement device based at least in part on the received messages. When the wireless communication is determined to be presently consistent, the intelligent electronic device may operate in a first mode. When the wireless communication is determined not to be presently consistent, the intelligent electronic device may operate in a second mode.

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Anaheim, CA, United States of America

Kei Hao