Det er også et problem, hvis der er underbelastning, idet netspændingen da stiger til over toleranceniveauet, og netoperatøren må så sørge for enten at frakoble produktionskapacitet eller at tilkoble forbrug.
A problem also arises if there is under-consumption as then the tension in the grid rises above an acceptable tolerance level and the transmission system operator must make sure that either some generation capacity is switched off or that some consumption is added.