Analytical Framework for Power System Strength

TL;DR

This paper introduces a comprehensive analytical framework with twelve indicators to evaluate power system strength, utilizing a novel Delta operator and complex frequency concepts, validated through numerical examples.

Contribution

The paper presents a new general framework with innovative differentiation techniques and indicators for assessing power system strength systematically.

Findings

Framework accurately quantifies system strength.

The Delta operator effectively captures algebraic variable jumps.

Numerical validation confirms the framework's precision.

Abstract

This paper proposes a general framework to evaluate power system strength. The formulation features twelve indicators, grouped in three dynamical orders, that quantify the resistance of bus voltage phasors and their first and second order rates of change to sudden current injection changes. To quantify such changes the paper introduces a novel finite differentiation technique, that we named Delta operator, able to properly capture "jumps" of algebraic variables and utilizes the recently developed concept of complex frequency. The paper also shows how the proposed framework can be systematically applied to any system device, and provides a variety of examples based on synchronous machines, converters and loads models are given. Numerical results in a benchmark system validate the exactness of the formulation.