Possible implementations of automatic voltage regulators for load flow analysis

Load Flow

The attached example project shows three different possibilities to implement automatic voltage regulators (AVR), installed along a line.

  • The most left arrangement uses an auto transformer, where the assigned type represents a real lossy transformer with discrete taps. The automatic tap changer controls the terminal of the connected load.
  • The second implementation uses a simplified lossless auto transformer with a continuous voltage regulation at the loads connection terminal, which leads to non-integer tap positions.
  • The third and last implementation uses an AC Voltage Source with two terminals. The assigned load flow controller is set to voltage control at the loads connection point. Since the element is a source it acts as such. In this case the flowing current through the element is untouched and only an additional voltage is fed in along the element. With the increased voltage and the constant current, the power values deviate from one another between the two connected terminals.
  • In addition to these automatic voltage regulators, the Common Impedance shows a possibility to implement a fixed voltage step via an ideal transformation (all R and X values = 0) using the Tap Ratio parameter.

The study case "WithControl" shows the impact of each implementation on the voltage (except for the Common Impedance as it represents no voltage control) compared to the results of a load flow calculation in the study case "WithoutControl".