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Grid line Frequency Measurement at every 1/2 cycle

Question asked by SlowJoe-Not-An-EE on Apr 16, 2015
Latest reply on May 21, 2015 by bobsbots

We currently use the ADE7763 to measure grid frequency but the value is of little value to our project as we now see the need to read grid frequency very quickly and very accurately. We are timing the ZX interrupts and averaging 6 of those together and then 10 of those samples together, and we have achieved the accuracy we are looking for but all of our data is delayed by up to 1 second. Is there a better device, such as the ADE7880 that can give us actual grid frequency every 1/2 cycle (every zero-crossing)? Is that asking too much from any system? We are trying to replace a system that the customer claims to evaluate Grid Hz every 1/2 cycle, so how are they doing that I wonder? I believe we could make it work if we had a really good frequency value every 2 or 3 cycles, what is the smallest/cheapest AD product that can produce a good value every 2-3 cycles? This is an isolated wind-diesel micro-grid application, and frequency varies from 59.8 to 60.3 Hz and we want to use frequency to adjust a dump load for grid frequency control.