Critical Clearing Time Sensitivity for Inequality Constrained Systems

TL;DR

This paper investigates how the critical clearing time (CCT) in renewable-rich power systems is affected by system parameters, using trajectory sensitivities to inform system stability and constraint management.

Contribution

It introduces the first-order sensitivity analysis of CCT in constrained power systems using trajectory sensitivities, highlighting the impact of system parameters on stability boundaries.

Findings

CCT sensitivity depends on system operating conditions and inertia.

Constraints on angles and frequencies influence stability margins.

Results aid in planning and revising protection settings.

Abstract

From a stability perspective, a renewable generation (RG)-rich power system is a constrained system. As the quasistability boundary of a constrained system is structurally very different from that of an unconstrained system, finding the sensitivity of critical clearing time (CCT) to change in system parameters is very beneficial for a constrained power system, especially for planning/revising constraints arising from system protection settings. In this paper, we derive the first order sensitivity of a constrained power system using trajectory sensitivities of fault-on and post-fault trajectories. The results for the test system demonstrate the dependence between ability to meet angle and frequency constraints, and change in power system parameters such as operating conditions and inertia.