In the case of the tested circuit is not open-loop, measure two AC voltages, current, phase between voltages, phase between currents, phase, frequency, phase sequence, active power, reactive power, apparent power, and power factor between voltage and current. Discriminate the transformer wiring group, inductive and capacitive circuits, test the secondary circuit and the busbar protection system, read the phase relationship between the CTs of the differential protection groups, check the wiring of the meter for correctness, and repair the line equipment, etc. 1. Model No.: ETCR4020 2. Simultaneous Measurement of Two Channel AC Current Range : 0mA~600A 3. Simultaneous Measurement of Two Channel AC Voltage Range: 0.00V~600V 4. Simultaneous Phase Test Between UI, II and UU Range : 0.0°~360.0° 5. Frequency Range: 45.00Hz～65.00Hz 6. Power Supply : DC9V Alkaline battery LR61.5V AAX6PCS