A/B/C PHASE DETERMINATION AND SYNCHROPHASOR MEASUREMENT USING COMMON ELECTRIC SMART METERS AND WIRELESS COMMUNICATIONS
First Claim
1. A method useful in determining an electric power phase relationship between two devices, one device comprising a power meter device connected to a power distribution system and the other device comprising another device connected to the power distribution system, the method characterized by processing one or more messages received from the second device, together with zero crossing data generated by the first device, to determine relative timing between zero crossings of power signals sensed at said devices.
1 Assignment
0 Petitions
Accused Products
Abstract
Phasor Measurement Units (PMUs) tend to be specialized and expensive—relegated to only key points in power distribution networks, and are generally reliant on GPS technology. The present disclosure details how any smart meter—using wireless communication—can perform sub-microsecond-grade synchrophasor measurements. Other aspects concern smart meter-based determination of A, B or C phase of the tri-phase power network. This can involve count-stamp enabling message packets sent to and/or from a smart meter, and then associating such count-stamps to local measurements of power phase by a metrology unit. Once a network of such enabled smart meters and other devices is formed, sub-microsecond metropolitan-wide and entire region-wide synchronizing time standard can calibrate local measurements of power phase, where simple A, B and C phase determination is one low hanging fruit application of such. Low cost aggregate monitoring of metropolitan-wide synchrophasors promises a next chapter of importance for that relatively recent art.
72 Citations
25 Claims
- 1. A method useful in determining an electric power phase relationship between two devices, one device comprising a power meter device connected to a power distribution system and the other device comprising another device connected to the power distribution system, the method characterized by processing one or more messages received from the second device, together with zero crossing data generated by the first device, to determine relative timing between zero crossings of power signals sensed at said devices.
-
11. A method of determining phase relationship among power meters, the method comprising:
-
collecting count stamped messages transmitted between nodes in a network including at least two power meters, the messages including zero crossing measurements of a power signal sensed at corresponding power meter; from the count stamped messages, determining relative timing among clocks within the power meters; from the relative timing and zero crossing measurements, determining relative phases between the power meters. - View Dependent Claims (12, 13)
-
-
14. A power meter comprising:
-
a metrology unit for measuring zero crossing of a power signal; a communication unit, in communication with the metrology unit for collecting zero crossing measurements and communicating count stamped messages including the collected zero crossing measurements to a remote node for determining relative phase between the power meter and another power meter. - View Dependent Claims (15, 16, 17, 18, 19)
-
-
20. A system comprising:
-
a network of communicating nodes, including at least two power meters; a node for collecting count stamped messages transmitted between nodes in a network including at least two power meters, the messages including zero crossing measurements of a power signal sensed at corresponding power meter; a node for determining relative timing among clocks within the power meters from the count stamped messages; and a node for determining relative phases between the power meters from the relative timing and zero crossing measurements. - View Dependent Claims (21, 22, 23)
-
-
24. A system including a first smart meter in digital packet communication with a second, separate smart meter, said meters including a metrology unit adapted to produce a counter or clock datum as a function of electric power phase, said meters including a communications unit adapted to produce a counter or clock datum as a function of sending and receiving communications packets, the system being configured whereby the first smart meter determines its electric power phase relative to the second smart meter by using a sent message as a common reference for two separate counters on the two separate meters.
-
25. A metrology unit for coupling to a power distribution network, comprising:
-
a zero-crossing detector; a free-running counter; and circuitry that outputs a value from the free-running clock when the detector senses a zero-crossing.
-
Specification