A system for controlling and automating an electric power delivery system by executing time coordinated instruction sets to achieve a desired result. A communication master may implement the execution of time coordinated instruction sets in a variety of circumstances. The communication may be embodied as an automation controller in communication with intelligent electronic devices (IEDs). The communication master may also be embodied as an IED that is configured to coordinate the actions of other IEDs. The time coordinated instruction sets may include steps for checking status of power system equipment before executing. The time coordinated instruction sets may include reactionary steps to execute if one of the steps fails. The time coordinated instruction sets may also be implemented based on a condition detected in the electric power delivery system, or may be implemented through high level systems, such as a SCADA system or a wide area control and situational awareness system.

Electric Power System Automation Using Time Coordinated Instructions

Systems and methods for distributing accurate time information to geographically separated communications devices are disclosed. Additionally, the desired systems and methods may adjust local time signals to compensate for measured signal drifts relative to more accurate time signals. Moreover, a system may determine a best available time signal based on a weighted average of available time signals or select a best available time signal based on weighted characteristics of various time signals. A system may be further configured to transmit time information embedded in an overhead portion of a SONET frame, including transmission of a standard or common time.

Fault tolerant time synchronization

An intelligent electronic device incorporates a first port that accepts a time signal from a time server over a network and a second port for receiving a second time signal over a separate network. The intelligent electronic device approximates the amount of error in the second time signal based on calculations of the error in the first time signal.

System and apparatus for measuring the accuracy of a backup time source

A system for managing an electric power delivery system is disclosed that includes a set of remote intelligent electronic devices (IEDs) and a central IED. The remote IEDs may be configured to obtain information related to rotor angles, operating frequencies, rate of change of frequency, rotating inertia, and power consumption levels of loads and generators included in the electric power delivery system. The central IED may communicate with the remote IEDs to determine which loads and generators are associated with a sub-grid of the electric power delivery system and whether to disconnected certain loads or generators. Based on this determination, the central IED may direct the remote IEDs to disconnect loads or generators from the electric power delivery system, or to rapidly increase or decrease generator output as appropriate.

Systems and Methods for Blackout Protection

Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.

Time distribution switch

In a utility monitoring system, a network of intelligent electronic devices (IEDs), including a master IED that receives master clock information from a global positioning system, includes a differential time synchronization (DTS) algorithm for automatically adjusting the corresponding clocks of each of the IEDs to be synchronized with the master clock information. A controller coupled to the network communicates instructions to the IEDs to collect frequency variation data. A known data alignment algorithm determines a point of alignment between two sets of frequency variation data, and the controller determines based on the data alignment algorithm output a time differential representing a time offset between the IED's clock and the master clock information. The time differential is communicated to the target IED, which advances or retards its clock based on the time differential.

Douglas Scharmann

Papers

Differential time synchronization of intelligent electronic devices