Small-disturbance voltage stability of OLTC & decentralized reactive power droop control

Increasing installation of decentralized generators in distribution grids can cause critical grid states. In case of critical nodal voltages on-load tap-changers (OLTC) and reactive power control based on nodal voltage, Q(V), are regarded as comparably cheap solutions to delay or even to replace distribution grid reinforcement. Since both control schemes are based on nodal voltages and usually share no communication infrastructure, local oscillations between controllers are possible. This publication investigates small-disturbance voltage stability and potential local plant control oscillations of OLTC and multiple Q(V) in a rural low voltage feeder via dynamic RMS analysis.