Assessment of PTDF Based Power System Aggregation Schemes

Power flow computations are essential for many
types of power system analyses. In order to reduce computation
time and reflect actual power market operation, network
aggregation principles are often used.
In this work we discuss network aggregation based on
power transfer distribution factors (PTDF), by testing three
different aggregation schemes. We analyze the performance of
the three schemes comparing their solutions with the results
obtained from a DC optimal power flow (DCOPF) performed
on the non-aggregated system. The performance is evaluated
on the IEEE 30-bus test system using three indicators; power
generation, inter-zonal flows, and total system costs.
To account for wind and load forecast uncertainty, we consider
a modified IEEE 30-bus system proposed to address massive
wind integration. The case study results show that the choice of
weighting scheme significantly impacts the results. In particular,
the PTDF aggregation schemes based on nodal injections (production
minus demand) and production outperform the pro-rata
aggregation scheme.