The hybridization of SCADA system by combining SCADA and PMU data is discussed in this paper. The hybrid system is called by WAMS hybrid with some PMUs is installed on the system while keeping the original SCADA data. The advantage of the WAMS hybrid is for improving the real time monitoring capability without installing so much PMU into the existing system. The optimum location of PMU determination based on the mean square error (MSE) increment is proposed. In addition, real time state estimation of SCADA and PMU data is also discussed in this paper.