Project with wattmeter in proteus works and in practice there is difference of values
pino1 = pino1+ ( ADC_Read(0) - 511.95  );


If ADC_Read(0) is 0 or not, pino1 = samples × -511.95.  This will account for your numbers, which should equal 59.5A (assuming ADC_Read(0) = 0). 

Additionally:

   current = pino1;
   current = current / samples;
   current = current * current;
   current = sqrt(current);
   current = current / 8.6f;                      


So current = current * current; and current = sqrt(current); do nothing.

I'll assume current = current / 8.6f;, factors out the -511.95.