Schweitzer Engineering Laboratories, Inc.

Luther S Anderson

Armando Guzman-Casillas

Bogdan Zdzislaw Kasztenny

Edmund O Schweitzer, Iii

Gregary C Zweigle

Tony J Lee

Normann Fischer

Witold R Teller

Douglas A Park

Steven A McMahon

Jeffrey B Roberts

James R Kesler

Gabriel Benmouyal

Joseph B Mooney

Mark J Bosold

Donald C Hicks

Mark W Feltis

Laurence Virgl Feight

An intelligent electronic device having a slow speed communications link creates one or more virtual communications channels using unused or dedicated bits from a primary real-time communications channel. The virtual communications channels are used to transport low-speed information, such as fault location information, device configuration information, device revision information, and date/time information.

Apparatus, system, and method for creating one or more slow-speed communications channels utilizing a real-time communication channel

A line current differential protection system that uses an external time reference continues providing protection to a power apparatus upon the loss of the external time reference. An external time reference synchronization mode and a channel based synchronization mode may be selectively applied on a per channel basis such that only those channels in the system that are not guaranteed to stay symmetrical use external time reference synchronization. When the external time reference is lost, fallback strategies may be used such as disabling or de-sensitizing the line current differential protection function, switching from the external time reference synchronization mode to a channel based synchronization mode with appropriately selected protection settings, and/or marking the channel as unavailable to isolate the system from the consequences of synchronization errors over this channel and instead using a master-slave mode with other available channels to continue providing line protection with the current differential system.

Line current differential protection upon loss of an external time reference

An apparatus and method estimates a plurality of synchronized phasors at predetermined times referenced to a common time standard in an electrical power system. The method includes acquiring and determining a frequency of a power system signal, sampling the power system signal at a sampling interval rate based on a frequency of the power system signal to form signal samples, and generating a plurality of acquisition time values based on an occurrence of each of the signal samples at a corresponding plurality of different times referenced to the common time standard. The method further includes adjusting a phasor of each of the signal samples based on a time difference between a corresponding selected acquisition time value and a predetermined time referenced to a common time standard to form the plurality of synchronized phasors.

Apparatus and method for estimating synchronized phasors at predetermined times referenced to a common time standard in an electrical system

An intelligent electronic device creates one or more virtual communications channels using unused or dedicated bits from a primary real-time communications channel. The virtual communications channels are used to transport low-speed information, such as executable commands, or automatic functions not requiring high bandwidth.

A wireless communications system for viewing and modifying memory locations within a power system device is provided including a wireless device and a power system device. The wireless device includes an input mechanism adapted to accept input from a user indicating a memory location the user wishes to view; a first radio frequency transmitter for transmitting a first signal including the memory location within the power system device the user wishes to view; and a first radio frequency receiver for receiving a second signal. The power system device includes at least one randomly accessible memory location and a processor coupled to at least one randomly accessible memory location; a second radio frequency receiver coupled to the processor and a second radio frequency transmitter coupled to the processor for receiving the first signal. The processor retrieves the value of the memory location included within the first signal and activates the second radio frequency transmitter to transmit a second signal including the value of the memory location. The value of the memory location may be a command or control that is executed by the power system device.

Faulted circuit indicator monitoring device with wireless memory monitor

A system is provided for adjusting settings of a power system device. In one embodiment, the setting adjusted is an identification setting of the power system device. The system generally includes an actuator having a select arrangement of magnets. A magnetic field sensor is provided for sensing the select arrangement of magnets. A microprocessor is coupled to the magnetic field sensor such that upon sensing the select arrangement of magnets by the magnetic field sensor, the microprocessor establishes an identification setting based upon the select arrangement. The various embodiments of the present invention provide an apparatus and system for adjusting settings of power system devices in harsh conditions, such as persistent in water.

Apparatus and system for adjusting settings of a power system device using a magnetically coupled actuator

A user interface for a wireless device used to monitor multiple groups of faulted circuit indicators. Each group of faulted circuit indicators includes a radio interface unit, which is coupled to each of the faulted circuit indicators in the group. The user interface includes an identification indicator, which includes a plurality of radio interface unit status indicators, each of which corresponds to a particular radio interface unit, and which indicates a selected radio interface unit. The user interface also includes a way indicator comprising a plurality of faulted circuit indicator status indicators, each of which corresponds to a particular faulted circuit indicator coupled to the selected radio interface unit. In addition, each radio interface unit status indicator indicates whether a particular radio interface unit coupled to a faulted circuit indicator is asserting a fault condition.

User interface for monitoring a plurality of faulted circuit indicators

A dynamically configurable relay element configured to protect an electrical system, including a dynamically calculated relay operating quantity, a dynamically calculated relay pickup setting, a dynamically calculated time dial, a plurality of dynamically calculated variables that define a characteristic of the dynamically configurable relay element, and a dynamically calculated operating time, the dynamically calculated operating time based on the dynamically calculated relay operating quantity, the dynamically calculated relay pickup setting, the dynamically calculated time dial and the plurality of dynamically calculated variables. The relay element may be an inverse-time overcurrent element, an instantaneous overcurrent element, an adaptive pickup overcurrent element, and inverse-time overvoltage element, a voltage restrained overcurrent element, and an inverse-time undervoltage element.

Dynamically configurable relay element and related methods

An apparatus and method estimates a plurality of synchronized phasors at predetermined times referenced to an absolute time standard in an electrical power system. The method includes acquiring and determining a frequency of a power system signal, sampling the power system signal at a sampling interval rate based on a frequency of the power system signal to form signal samples, and generating a plurality of acquisition time values based on an occurrence of each of the signal samples at a corresponding plurality of different times referenced to the absolute time standard. The method further includes adjusting a phasor of each of the signal samples based on a time difference between a corresponding selected acquisition time value and a predetermined time referenced to an absolute time standard to form the plurality of synchronized phasors.

Apparatus and method for estimating synchronized phasors at predetermined times referenced to an absolute time standard in an electrical system

The relay system obtains voltage and current values from a power line and uses a first sampling element to sample the voltage and current values at selected intervals of time. The resulting sampled signals are used for power system-wide protection, control, monitoring and metering. The sampled signals are then resampled at a rate which is a selected multiple of the power system frequency. The results of the resampling are used by processing circuitry for protection functions including fault determinations.

Protective relay with synchronized phasor measurement capability for use in electric power systems

The system includes a plurality of protection application elements to accomplish various power system protection functions, including for example line protection, line fault location, current direction determination, breaker protection and synchronism check, among others. The system includes local sources of current and voltage information for the protective functions as well as a receiving section for receiving such current and voltage values from a remote source, such as another protection device, as well as other necessary input information for the protective functions. A selection logic section is responsive to the output of the protective function elements, as well as the local and remote data to determine whether the primary or local sources are to be used. The outputs of the protective function elements are used by an output section to control circuit breakers and the like and are also transmitted, with the local and remote source quantities, to other protective devices.

Voltage and current source selection system for use in the protection, automation and control of an electric power system

The residual phase currents for each selected winding of a transformer are first determined and then summed to provide a value designated I.sub.X. The neutral current for the transformer is also determined, with the neutral current being designated I.sub.Y. A directional element calculates a torque value T according to the following formula: T=R.sub.e (I.sub.X .multidot.I.sub.Y *). This torque value will be negative for an external (reverse) fault, and positive for an internal (forward) fault. The quantity of the torque is compared against threshold values before a forward or reverse fault for the transformer is declared.

Restricted earth fault protection for transformers using a directional

A breaker failure relay circuit is responsive to either a trip signal from a protective relay or a manual trip signal, as well as the current through a circuit breaker protecting a transmission line. The trip signal is applied to an edge triggered timer (28) having selected pickup and dropout times, and is also applied as one input to one OR gate (24). The circuit breaker current is applied to an overcurrent element (34), the output of which is applied to a reset input of the edge triggered timer (28) to reset and disable the timer and also as one input to another OR gate (30). The other input to OR gate (30) is the output of the edge triggered timer (28). The outputs of OR gates (24, 30) are applied to an AND gate (26), the output of which is applied to a second timer (32) and as another input to the one OR gate (24). The output of the timer (32), if and when it occurs, is used as a trip signal for a backup circuit breaker.

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Pullman, WA, United States of America

Luther S Anderson