GF312B2 portable three phase reference meter high accuracy 0.02%, with all kinds of optional clamp on ct and smart optical sampler. It can be applied in electrical laboratory or on site. it will be ensured by a combination of measures such as the use of 24bit A/D converter, DSP+32 bit ARM technology, a widely measuring range 600V/120A, adapted to typical test points of most recognized national metrological institutes. It can be as high precision three phase reference energy meter, also three phase portable meter calibrator, test ct pt ratio, burden etc.