Abstract: Continuous monitoring of an electric power system during testing of a primary electric power meter is described herein. Electric power system signals or test signals may be selectively supplied to the primary electric power meter. Electric power system signals may be supplied to a secondary meter while a test signal is applied to the primary electric power meter. The secondary meter may record and/or transmit monitoring functions and communicate the results of the monitoring functions to the primary electric power meter while the test signals are supplied to the primary electric power meter.

Abstract: Continuous monitoring of an electric power system during testing of a primary electric power meter is described herein. Electric power system signals or test signals may be selectively supplied to the primary electric power meter. Electric power system signals may be supplied to a secondary meter while a test signal is applied to the primary electric power meter. The secondary meter may record and/or transmit monitoring functions and communicate the results of the monitoring functions to the primary electric power meter while the test signals are supplied to the primary electric power meter.

Abstract: Provided is an intelligent electronic device-to-intelligent electronic device direct communication system in a power system, for performing a power system data redundancy check therebetween. The communication includes a first intelligent electronic device adapted for deriving power system data from a selected portion of the power system. The first intelligent electronic device is associated with a first transmit module for transmitting the derived power system data. A second intelligent electronic device is further provided and adapted for deriving power system data from the selected portion of the power system, wherein the second intelligent electronic device is associated with a first receive module.

Abstract: A local speaker within a multi-group conference is identified on a remote display by displaying a representation of the speaker, which could be the speaker's image, name, or other identifying information, on a remote display. The speaker is identified by an identification mechanism, such as a bar code reader, coupled to the microphone assigned to the speaker. The speaker's identification information is transmitted from the local location to the remote location, where the speaker's representation is retrieved and displayed.

Abstract: The current differential relay operates without adjustable settings, and includes a phase current differential element with a predetermined threshold, responsive to local phase current values and remote phase current values, to detect three-phase faults and producing a first output signal if the threshold value is exceeded. Either a negative sequence current differential element or two phase current differential elements, also having predetermined threshold values and responsive to the local and remote phase currents, detect phase-to-phase faults and phase-to-phase-to-ground faults and produces a second output signal if the predetermined threshold is exceeded. A negative sequence or zero sequence current differential current element, with a predetermined threshold value is responsive to the local and remote phase currents to detect phase-to-ground faults and to produce a third output signal if the threshold is exceeded.

Abstract: Provided is an intelligent electronic device-to-intelligent electronic device direct communication system in a power system, for performing a power system data redundancy check therebetween. The communication includes a first intelligent electronic device adapted for deriving power system data from a selected portion of the power system. The first intelligent electronic device is associated with a first transmit module for transmitting the derived power system data. A second intelligent electronic device is further provided and adapted for deriving power system data from the selected portion of the power system, wherein the second intelligent electronic device is associated with a first receive module.

Abstract: The communication system provides audio communication with a user over a phone system of messages and other information originated in non-audio form by a protective device such as a protective relay or the like for an electric power system. The communication system includes a text-to-voice conversion processor responsive to the messages provided by the protective device, and an access control system for establishing phone system communication with a user, including answering incoming telephone calls from the user and initiating dialing-out calls with selected users having telephone numbers known to the communications system. Text material from a protective device is converted to audio and provided to a user, such as a technician for the power system.

Abstract: Provided is a compensated inverse-time undervoltage load shedding system and method for use in an electrical power system. The compensated inverse-time undervoltage load shedding system includes a compensation element for determining a compensated value and an inverse-time undervoltage element operatively coupled to the compensation element and enabled based on the compensated value. When enabled, the inverse-time undervoltage element calculates a load shedding time delay value based on the compensated value, and determines a load shedding signal based on the load shedding time delay value. An associated load of the electrical power system is shed based on the load shedding signal. The compensation element may determine the compensated value using a voltage magnitude, a rate-of-change of power system voltage over time, a weighted rate-of-change of power system voltage over time, a current magnitude, a weighted current magnitude, and an impedance phasor value, to name a few.

Abstract: The system is used in a distance-type protective relay which includes a calculation circuit responsive to voltage and current values from a power line to produce a quantity which is analogous to the distance between the relay and a fault on the line, referred to as an m quantity. This quantity is then applied to a distance element/circuit for comparison of said quantity with a setting reach value for a zone one distance protection to determine whether the fault is within zone one protection. The system includes a filter circuit which filters the quantity before it reaches the distance element, resulting in a smoothing of said quantity and rejection of noise therefrom. The system further includes a control circuit which determines whether the filter is to be used in the system in a particular situation, depending upon whether when the value of the quantity is above a selected percentage of the setting reach value.

Abstract: The system includes a distance protective relay for power lines which includes a logic capability which is responsive to settings entered into the relay by an end user to implement the value of those settings into stored thermal model equations which emulate the temperature of the power line conductor. The logic within the relay is organized and has the capability of receiving the setting values entered by the user and to use those in the logic equations to determine the temperature of the conductor.