if (ptc.voltageStepIncrementOutOfPhaseIsSet() && ptc.getVoltageStepIncrementOutOfPhase() != 0) { du = (config.isInvertVoltageStepIncrementOutOfPhase() ? -1 : 1) * ptc.getVoltageStepIncrementOutOfPhase() / ptc.getTransformerWinding().getRatedU(); } else if (ptc.stepVoltageIncrementIsSet() && ptc.getStepVoltageIncrement() != 0) {