Smart Meter
- 詳細技術說明
- Smart Meter
- *Abstract
-
Inelectrical engineering, a device to measure current is a clamp or current-probewith two jaws that open and allow clamping around an electrical conductor. Thisallows the electrical current in the conductor to be measured without having tomake physical contact with it, or having to disconnect it for insertion throughthe probe. An electrical meter with an integral current clamp is known as aclamp meter, clamp-on ammeter, or tong tester. Currently, several types ofclamp meters exist which include: Rectifier, Split Ferrite Ring, iron Vane,Hall-Effect, and Open Jaw.
Conventionalclamp meters have certain shortcomings the most notable of which is that onlyone conductor is passed through the probe, requiring the conductors of multiconductor cables to be separated before the current in one conductor can bemeasured. Electrical installation codes for commercial and residentialproperties forbid the opening of cables or the separating of wires. If morethan one conductor were to be passed through, the measurement would be the vectorsum of the currents flowing in the conductors which could be very misleadingdepending on the phase relationship of the currents. In particular, if theclamp is closed around a two-conductor cable carrying power to the equipment, wherethe same current flows down on conductor and up the other, then theconventional meter will falsely provide a reading of zero. Conventional currentclamp meters have been available for many years and are an accepted method ofnon-intrusive current measurement. However, these instruments can only measurecurrent in a single core-cable, requiring multi-core cables to be separatedbefore one core can be measured. Where these current meters fail, the presentinvention excels in that it takes advantage of the magnetic field patternsurrounding a multiple-conductor cable to provide accurate readings of ACcurrent using simple and inexpensive components.
Currentin multi-core cables can be measured without the need to split cores by usingan array of magnetic sensors to determine the magnetic field patternsurrounding the two, three, or four-core cable and computing the currentflowing in each conductor from this magnetic field profile. Our technology is adevice and procedure to measure the alternating electric current in a multi-conductorcable. The current meter disclosed here has only a small number of coils (oneor two) and uses a large number of turns in each coil to obtain a robust signaloutput. Our current meter can have a coil geometry and placement that may beoptimized with respect to certain parameters with the optimal arrangement beingachieved when an output signal is strong and accurately proportional to theelectric current in the cable while also being insensitive to smalldisplacements between the cable and meter.
- *IP Issue Date
- None
- *IP Type
- Other Patent
- 國家
- Not Available
- 申請號碼
- None
- 國家/地區
- 美國
