It is necessary to study the distribution of space charge after the long-term operation of the cross-linked polyethylene（XLPE） power cable under AC stress. In order to study the dynamic characteristic of space charge in the insulation of cable

we developed a space charge measurement system used for full-size cable under AC electric stress based on the pulsed electro-acoustic（PEA） method. Using automatic equal phase shift principle（AEPS）

we could obtain a high phase-resolution space charge signal by setting the frequency of the periodic electric field and detecting pulse properly

without any phase detection and synchronization module. The hardware parameters were determined by the Multisim simulation

which ensures the feasibility of the system. The space charge measurement and analysis were carried out on a 8.7/10 kV XLPE cable under 50 Hz AC stress. In order to overcome the frequency fluctuation

two data analysis modes were pointed out. The accuracy of the space charge profile could be determined by the relationship of the AC frequency error and average time. The results show that a relatively high phase resolution of 1.79°

as well as accurate space charge profiles

can be obtained. The high accuracy of the measurement system is also proved through the space charge detection under different electric fields.