In the simulation package GTM-X two methods are available that approximate the electric potentials in the glass melt in the prescience of multiple transformers. Both methods control the grouped electrodes in such a way that power consistency is is guaranteed, also for complicated electrode groupings and transformer systems. By power consistency we mean that the total heat release, as calculated from the potentials and currents at the electrodes, matches the power that is released in the volume cells. The first method approximates two scalar potentials; it may violate the constraints that electrical currents are conserved for electrode group (or transformer); the results is that also this additional constraint can be satisfied. In this article we discuss these two methods and show results for a model problem.
