3 phase sensing

[ccdubs]

Hi,

Could someone explain what 3 phase sensing is to me in terms of an automatic voltage regulator for grid generation purposes.

I have read that it should be used when a load is non-linear and fluctuating, but I don't understand why this requires 3 phase sensing?

If the generator has a fluctuating power prime mover e.g., wind, does this necessitate 3 phase sensing?

 

[Marke]

Generally, there are two ways of monitoring the voltage, one way, the cheapest way is to measure on one phase only and this is often done with a single diode and capacitor so that the measurement is essentially a half wave peak measuring device. The more comprehensive way is to use a threephase full wave bridge. This is usually and averaging system and when you use a three phase full wave rectifier without smoothing, you only get 16% ripple so very little smoothing is required. The peak measurement is going to be very susceptable to any distorions or transients that occur on the crest of the waveform. The three phase averaging method is much more immune to such problems. Additionally, the threphase full wave measurment is constantly updated as opposed to one update per cycle with the half wave single phase system. The three phase measurements are much more able to track variations quickly and therefore tend to be much more stable.
Mark Empson

http://www.lmphotonics.com

 

[jbartos]

Suggestion: Visit

http://www.basler.com/html/rscanalog.htm

for more info and literature on single and three phase regulator sensing

 

[jbartos]

Suggestion: Essentially, three-phase sensing senses all three phase to phase voltages and associated information in these voltages, which may be used by various algorithms. The single phase sensing senses one phase to phase voltage, which misses information in the remaining two phase to phase voltages.