Inverter Based Resource With a Long Feeder: Modeling and Experimental Validation

This work presents a comprehensive analysis of Inverter-Based Resource (IBR) performance with long feeders. It is a configuration that has been increasingly common in several power system applications, ranging from renewable interconnections such as offshore wind farms to oil exploitation pumping systems. This work shows that simplified modeling approaches yield significant inaccuracies in predicting system behavior. Analysis reveals that an ideal IBR representation coupled with detailed feeder modeling fails to predict responses at the receiving end accurately. Similarly, detailed IBR modeling with simplified feeder representation also produces inadequate results. In the latter, the feeder is treated as a single-phase equivalent to frequency-dependent and distributed characteristics. Accurate system response prediction requires simultaneous consideration of the actual IBR voltage waveform and detailed feeder representation equivalent to those used in wideband transient testing. This integrated modeling approach captures the complex interactions between harmonic-rich IBR outputs and the distributed impedance characteristics of long feeders. The experimental results were carried out at an operational oil company facility housing the long-feeder. The feeder is a 12/20 kV, 2.5 km umbilical cable wound on a drum. Due to space restrictions in the facility, only a low-voltage IBR was used. It is connected to the feeder without an output filter to create a harmonic-rich environment. All the simulations were carried out using the Numerical Laplace Transform.