The comprehensive and in-depth development of smart grid has brought new demands for the safe and reliable operation and intelligent analysis of substation automation system. For this reason, State Grid Corporation of China has put forward the “four unification, four standard” requirements for automation products. This paper introduces a device that meets the requirements of the phasor measurement unit “four unification, four standard”. The basic structure of the function module is discussed. The research content of the key technology of the device is expounded. A real time calculation model of synchronous phasor for restraining out of band frequency is introduced, and testing results show that this algorithm is far better than the standard requirements. A double interpolating FFT subsynchronous and supersynchronous oscillation monitoring algorithm based on Hamming window is proposed, and simulation results show its effectiveness. The mechanism of the pseudo low frequency oscillation / subsynchronous oscillation in DC converter station is revealed, and the sampling frequency requirement for DC converter station is proposed. The functions of current calculation, quality processing, multiple interval PT/CT line judgment logic and so on are described. Finally, the device information model and the related content of communication service are introduced. This work is supported by Science and Technology Project of the Headquarter of State Grid Corporation of China (No. 520900160006).