The power frequency laboratory at UHV RL was set up mainly to undertake major electro technical and mechanical research & development studies and also to undertake testing activities for equipment ranging up to 1200 kV. Major electrical research & development studies undertaken are -corona power loss, electric field and magnetic field effects, radio and TV interference, audible noise etc. from transmission lines.

The laboratory is equipped with 1600 kV / 6A (continuous) Power frequency voltage source. Two 800kV transformers are connected in cascade.  The tests performed in this laboratory are one-minute dry and wet withstand test, flashover test, Radio interference voltage test, visible corona test, voltage distribution tests, Ferro resonance tests etc. The system is also used for carrying out R&D work on experimental transmission line and conduct pollution testing and research.

Test voltage is derived by means of AC testing system either single or cascade arrangement of transformers depending on voltage levels required. Thus, the measuring system consists of a converting device like divider and an indicating instrument.  The system conforms to IEC 60060. For measurement of voltage, capacitive voltage dividers are used. For RI measurements, 1200 kV coupling capacitor with EMI receiver is used.