Bus Type Switching to Reduce Bound Violations in AC Power Flow

TL;DR

This paper introduces a novel bus type switching method in AC power flow analysis that reduces bound violations and improves feasibility by adjusting bus types to better satisfy system constraints.

Contribution

It proposes an augmented AC power flow approach with new bus types to effectively address voltage bound violations and enhance solution feasibility.

Findings

Reduces voltage and thermal violations in test cases

Improves feasibility of power system setpoints

Demonstrates effectiveness on multiple IEEE test systems

Abstract

Wholesale power markets often use linear approximations of power system constraints. Because it does not consider inequality constraints, using AC power flow for feasibility post-processing can violate bounds on reactive power, voltage magnitudes, or thermal limits. There remains a need for a streamlined analytical approach that can guarantee AC feasibility while adhering to variable bounds. This paper suggests an augmented implementation of AC power flow that uses an additional two bus types (PQV and P) to help resolve voltage bound violations present in the traditional approach. The proposed method sacrifices the voltage setpoint at a generator in exchange for fixing the voltage at a load bus, thereby moving a degree of freedom around the network. Results on the IEEE 14-bus, 57-bus, and 300-bus test cases demonstrate how switching bus types can reduce overall network violations and help find feasible power system setpoints.