Analyses on the Adaptability of the Branch Voltage Stability Index in the Distribution Network Interconnected with PV

With the interconnection of large scale of distributed photovoltaic into the distribution network, the voltage stability assessment for the distribution network needs for appropriate indicators. Based on the actual system modeled with PSD-BPA software platform, we compared the adaptability for the branch voltage indexes in the distribution network, from the viewpoint of simulation in different operation condition and derivation. The four indexes are the L
_p
and L
_q
obtained based on the quadratic equation, the voltage branch index D
_vij
based on the sensitivity limitation and the improve voltage branch stability index L
_pqu
. The simulations and analyses show that the improvement of the voltage branch stability index L
_pqu
is only necessary for the accuracy of the relative stability and the indicator of the voltage collapse point. Its calculation only involves the measurement of the voltage phase at the two ends of the branch, which is independent of the variable line parameters in the actual situation, so the “model-free” index L
_pqu
is more suitable for the voltage stability assessment of the distribution network containing the photovoltaic.