Sensitivity Analysis

Sensitivity analysis in power systems quantifies how a small change in an input or control variable affects a calculated system result. It gives engineers a fast way to estimate the effect of redispatch, reactive support, or topology adjustments without solving every alternative from scratch.

Key Aspects of Sensitivity Analysis:

• Incremental Response: A sensitivity factor measures the local slope between cause and effect, such as how much a bus voltage changes when reactive power is injected or how much a line flow changes when generation shifts between two buses.
• Jacobian-Based Methods: Many sensitivity factors are derived from the power flow Jacobian or related linearized network models. This makes them computationally efficient and well suited for screening many candidate actions quickly.
• Operational Decisions: Operators use sensitivities to rank control actions, for example deciding which generator redispatch best relieves a congested line or which bus is most effective for reactive compensation.
• Market and Planning Use: Sensitivity factors underpin many market calculations, including transfer distribution factors and congestion impact estimates. In planning, they help identify where reinforcements or voltage support devices will provide the greatest benefit.
• Validity Range: Because sensitivity analysis is a local linear approximation, it is most reliable for relatively small changes around the studied operating point. Large disturbances still require a full nonlinear study.