Method and apparatus for synchronizing data in utility system
First Claim
1. A system for synchronizing a plurality of monitoring devices in a power system to a common time reference, comprising:
- a time synchronization device that includes a reference clock, a signal generator, and a first controller programmed to cause the signal generator to generate a synchronization signal at periodic time intervals that are synchronized with the reference clock, the signal generator coupling the synchronization signal over an energized power conductor carrying a current or voltage that oscillates at a fundamental or nominal frequency of the power system, the synchronization signal being distinct from the current or voltage carried by the energized power conductor and having a frequency greater than the fundamental or nominal frequency of the power system and a magnitude that exceeds a noise floor associated with the power system; and
a monitoring device coupled to the energized power conductor, the monitoring device including a detection module that detects the current or voltage carried by the energized power conductor, a communications interface communicatively coupled to a remote system that is remote from the monitoring device and the time synchronization device, and a second controller coupled to a memory, electrical data indicative of the detected current or voltage being stored in the memory, the second controller being programmed to;
detect at least the frequency or the magnitude of the synchronization signal and, in response thereto, to store data in the memory indicative of the detection of the synchronization signal;
synchronize the electrical data with the reference clock by adjusting a time of an on-board clock or a cycle counter in the monitoring device responsive to the detected synchronization signal; and
transmit, via the communications interface, the synchronized electrical data to the remote system.
2 Assignments
0 Petitions
Accused Products
Abstract
A time synchronization device (TSD) that produces a synchronization signal and couples it onto energized power conductors in a power monitoring system. Monitoring devices coupled to the TSD include frequency detection algorithms, such as a Goertzel filter, for detecting the synchronization signal and interpreting the information encoded in the signal. The frequency of the synchronization signal may correspond to the fourth or tenth harmonic component of the fundamental frequency of the voltage on the power conductors. The magnitude of the signal is selected to be above the expected or established noise floor of the power monitoring system plus a predetermined threshold. The duration of the signal can be varied, such as lasting a full cycle of the fundamental frequency. Multiple TSD signals received in a predetermined sequence may be converted into digital words that convey time, configuration, reset, control, or other information to the monitoring device.
-
Citations
18 Claims
-
1. A system for synchronizing a plurality of monitoring devices in a power system to a common time reference, comprising:
-
a time synchronization device that includes a reference clock, a signal generator, and a first controller programmed to cause the signal generator to generate a synchronization signal at periodic time intervals that are synchronized with the reference clock, the signal generator coupling the synchronization signal over an energized power conductor carrying a current or voltage that oscillates at a fundamental or nominal frequency of the power system, the synchronization signal being distinct from the current or voltage carried by the energized power conductor and having a frequency greater than the fundamental or nominal frequency of the power system and a magnitude that exceeds a noise floor associated with the power system; and a monitoring device coupled to the energized power conductor, the monitoring device including a detection module that detects the current or voltage carried by the energized power conductor, a communications interface communicatively coupled to a remote system that is remote from the monitoring device and the time synchronization device, and a second controller coupled to a memory, electrical data indicative of the detected current or voltage being stored in the memory, the second controller being programmed to; detect at least the frequency or the magnitude of the synchronization signal and, in response thereto, to store data in the memory indicative of the detection of the synchronization signal; synchronize the electrical data with the reference clock by adjusting a time of an on-board clock or a cycle counter in the monitoring device responsive to the detected synchronization signal; and transmit, via the communications interface, the synchronized electrical data to the remote system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method of communicating a synchronization signal that is interpreted simultaneously by a plurality of monitoring devices in a power system, comprising:
-
generating a synchronization signal having at least a frequency, a magnitude and a duration; coupling the synchronization signal via power line communication (PLC) onto one or more power conductors to which the plurality of monitoring devices are coupled at periodic time intervals that are determined by a reference clock external to the plurality of monitoring devices, the one or more power conductors carrying a current or voltage oscillating at a fundamental or nominal frequency of the power system, the synchronization signal being distinct from a current carried by the one or more power conductors, wherein the frequency of the synchronization signal is greater than the fundamental or nominal frequency and the magnitude of the synchronization signal exceeds a noise floor associated with the power system; monitoring, by each of the plurality of monitoring devices, a characteristic associated with the current or voltage carried by the one or more power conductors to which each of the plurality of monitoring devices is coupled, and storing the monitored characteristic as corresponding electrical data in a respective memory of each of the plurality of monitoring devices; receiving, simultaneously at each of the plurality of monitoring devices, the synchronization signal from the one or more power conductors; detecting at least the frequency or the magnitude of the synchronization signal; responsive to the detecting, storing in the memory of each of the plurality of monitoring devices, data indicative of the detection of the synchronization signal; synchronizing the respective electrical data from each of the plurality of monitoring devices with the reference clock by adjusting a time of an on-board clock or a cycle counter in at least one of the plurality of monitoring devices responsive to the detected synchronization signal; and receiving, in a remote system, the synchronized electrical data from each of the plurality of monitoring devices. - View Dependent Claims (14, 15, 16, 17, 18)
-
Specification