AHFs are offered in a range of voltages, most common is 200V up to 690V. Some manufacturers can produce AHFs for higher voltages, up to 1000V, without step-up transformer, reducing

costs and footprint. It is possible to connect AHFs to high voltage (over 1kV) systems using a suitable step-up transformer.

Step-up (or step-down) transformers can reduce compensation performance due to increased impedance between the AHF and

network.