The Difference Between SCADA and WAMS Real-Time Data in Dispatching Center

With the online real-time statistical data from the dispatching centers of power system,the similarity and real-time difference between RTU and PMU measurements are compared in this paper,and it is found that the data of RTU and PMU from straight telemetered measurements at a physical site are in difference with 1 s of time delay; the differences of active power,current magnitude and voltage magnitude between PMU and RTU are generally less than 2%; but that of reactive power between the two devices usually range from 5%- 40%. The analysis shows that in the calculation of power system,the measurement data of active power,current magnitude and voltage magnitude from PMU can be used directly,but that of current angle and voltage angle should not be used directly while that of reactive power should be used selectively. It is proposed to improve the accuracy of PMU phase angle measurements through periodically checking and adjusting of the phase angle compensation parameters.