Ahmad moradi - Department of engineering, Islamic azad University south branch , Tehran, Iran
Mehdi hamzeh neysiyani - Department of engineering, Islamic azad University south branch , Tehran, Iran
Mohammad mortazi - Department of engineering, Islamic azad University south branch , Tehran, Iran
Iman minaee - Department of engineering, Islamic azad University south branch , Tehran, Iran

Partial Discharge (PD) measurement is a precise diagnosis to give the knowledge about the condition of the insulation. There are several methods to detect and measure the PD such as Electrical, Acoustic, Optical, Chemical and Ultra High Frequency (UHF) detection methods. Among all these methods, UHF sensor plays crucial role to detect the PD, efficiently with high sensitivity. PD pulses tend to appear only in the time of nano -seconds, which pulses can be detected without any power outage by using high bandwidth antenna i.e. UHF sensor. It has been confirmed that the frequency of the PD pulse generated in cables can reach up to GHz, while the frequency of background no ise usually lies below 400MHz.Experiments show that the UHF PD pulse can radiate from the disconnection between the shields in the sealing ends or the joints, and it can also radiate out along the ground w ire or the cross -linked wire. Moreover, the detection by UHF sensor towards four different types of PD models have been done in laboratory, such as sliding discharge model, floating discharge model, protrusion discharge model and cavity discharge model. Mass of statistic results of these PD pulses indicate the distinct characteristics. It can help to do the pattern recognition research, even to do further research on fault diagnosis for XLPE cables.

PD, Detection UHF, power cables, Capacitor coupler, Insulation