Grid Voltage Amplitude and Frequency Real-Time Estimation using Linear Kalman Filter

The paper deals with hardware-in-the-loop (HIL) laboratory setup consisting of the arbitrary waveform generator (AWG) and the device used for grid voltage fundamental harmonic amplitude and frequency real-time (RT) estimation. The device under test (DUT) is realized as desktop target PC with Phar Lap RT operating system using NI PCIe 6251 DAQ card. On the other hand, the AWG serves as a three-phase or single-phase grid disturbance simulator. The algorithm based on the linear Kalman filter and the frequency-locked loop has been used as robust and accurate estimation technique. Both AWG and DUT have been driven from the host PC. Furthermore, LabViewallows user to configure and perform remote online monitoring of the DUT, i.e., to track amplitude and frequency changes point-by-point on the host PC over Ethernet TCP/IP protocol. The AWG allows various real-time case study analysis to be performed in accordance with up to date power quality standards. For a selected case studies, the DUT is verified by comparing experimental results against IEEE and IEC standards for power quality analysis. An example of grid voltage amplitude and frequency online monitoring is also presented. Moreover, proposed HIL laboratory setup can be used for comparison of various estimation techniques for control and protection purposes in microgrids.