Two main measuring techniques

narrow band detection and ultrawide band（UWB）detection

are generally applied in partial discharge （PD） measurement.It will help to achieve more reliable and useful information and higher signal to noise ratio with UWB detection than narrow band detection.Whereas

it has been abundant experience with narrow band detection

so it is a good idea to detect PD simultaneously with narrow and ultrawide band method. Moreover

based on the relations between the detected results of the two techniques

it will help to use the research results effectively that already existed. Rejecting and suppressing on site interference is the precondition of PD measurement. Some measures of interference rejection are given in this paper.