Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Aggregate Power Flexibility in Unbalanced Distribution Systems   With a large-scale integration of distributed energy resources (DERs),
distribution systems are expected to be capable of providing capacity support
for the transmission grid. To effectively harness the collective flexibility
from massive DER devices, this paper studies distribution-level power
aggregation strategies for transmission-distribution interaction. In
particular, this paper proposes a method to model and quantify the aggregate
power flexibility, i.e., the net power injection achievable at the substation,
in unbalanced distribution systems over time. Incorporating the network
constraints and multi-phase unbalanced modeling, the proposed method obtains an
effective approximate feasible region of the net power injection. For any
aggregate power trajectory within this region, it is proved that there exists a
feasible disaggregation solution. In addition, a distributed model predictive
control (MPC) framework is developed for the practical implementation of the
transmission-distribution interaction. At last, we demonstrate the performances
of the proposed method via numerical tests on a real-world distribution feeder
with 126 multi-phase nodes.

22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph