EREA Energy Engineering has developed voltage measurement transformers for one- and three-phase measurements. These transformers stand out because of their high accuracy in transforming primary voltage to secondary voltage. Under conditions of normal use, secondary voltage should be perfectly proportional to the primary voltage and it should have a phase displacement of zero degrees towards the primary voltage. Voltage measurement transformers are used to adjust the voltage at the input impedance of the measuring instrument or for the creation of a galvanic isolation. They are used as power sources for measuring instruments, energy meters, relays and other analogue equipment.