Analytical Framework for Power System Strength
For power system engineers, this provides a systematic method to assess system strength across various devices, though it is an incremental extension of existing concepts.
The paper proposes a general framework with twelve indicators across three dynamical orders to evaluate power system strength by quantifying bus voltage phasor resistance to current injection changes. Numerical results validate the formulation's exactness.
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.