Intelligent electronic device and method thereof
An intelligent electronic device (IED) having a gain control unit adapted to selectively regulate operating ranges of output signals of a sensing circuit of the device is described. In one embodiment, the IED is a digital electric power and energy meter, which operating ranges for supply voltages and supply currents of electrical services may be adjusted to match pre-determined ranges for input signals of a data acquisition system or a data processing module of the meter.
1. An intelligent electronic device, comprising:
a metering module coupled to an AC electrical service that measures at least one parameter of the AC electrical service; and
a processing module that processes data obtained using the metering module;
wherein the metering and processing modules form (i) first measuring channels time-locked to zero-crossing points of supply voltages or supply currents of the AC electrical service, and (ii) second measuring channels time-locked to pre-determined moments of time.
2. The device of claim 1 , wherein the zero-crossing points are moments of time when a polarity of the supply voltages or the supply currents changes from a negative polarity to a positive polarity.
3. The device of claim 1 , wherein the zero-crossing points are moments of time when a polarity of the supply voltages or the supply currents changes from a positive polarity to a negative polarity.
4. The device of claim 1 , wherein the first measuring channels measure the at least one parameter during a pre-determined number of cycles of an AC frequency of the AC electrical service.
5. The device of claim 1 , wherein the second measuring channels measures the at least one parameter during a pre-determined time interval.
6. The device of claim 1 , wherein the first measuring channels measure numerical values of the at least one parameter selected from the group consisting of a line voltage, a line current, a phase voltage, a phase current, or a root mean square (RMS) value thereof; energy, revenue, real power, reactive power, total power, and a power factor.
7. The device of claim 1 , wherein the second measuring channels measure the at least one parameter selected from the group consisting of a waveform of a line voltage, a waveform of a line current, a waveform of a phase voltage, a waveform of a phase current; and a total harmonic distortion or harmonics thereof.
8. The device of claim 1 , wherein the processing module processes and/or stores data produced by the first measuring channels or the second measuring channels.
9. The device of claim 1 , wherein said device further comprises a user interface unit that displays data produced by the first measuring channels, the second measuring channels, or the processing module or configuration settings of the device.
10. The device of claim 1 , wherein said device further comprises a communication module that transmits to a remote terminal data produced by the first measuring channels, the second measuring channels, or the processing module or configuration settings of the device.
11. The device of claim 1 , wherein said device is selected from the group consisting of a digital electrical power and energy meter, a Programmable Logic Controller (PLC), a Remote Terminal Unit, a protective relay, or a fault recorder.
12. The device of claim 1 , wherein said device is a digital electrical power and energy meter.
13. The device of claim 1 , wherein the second measuring channels measures the at least one parameter including a waveform of at least three phase voltages and a waveform of at least three phase currents, the waveforms being sampled continuously.
14. The device of claim 13 , wherein each waveform is captured upon an event, each waveform including 2048 samples per capture.
15. The device of claim 1 , wherein the processing module allocates at least one buffer.
16. The device of claim 15 , wherein the at least one buffer includes at least one of a frequency locked sample buffer, RMS buffer, time-locked sample buffer and/or an auxiliary buffer.
17. The device of claim 15 , wherein the at least one buffer includes a first in first out (FIFO) buffer.