Influence of Sensor Feedback Limitations on Power Oscillation Damping and Transient Stability

TL;DR

This paper analyzes how sensor feedback limitations affect power oscillation damping and transient stability, revealing a trade-off where improved damping can reduce stability margins, validated through simulations on a test system.

Contribution

It derives fundamental sensor feedback limitations for rotor stability control and demonstrates the impact of local measurements on damping and stability through system simulations.

Findings

Improved damping reduces transient stability margins.

Local measurements cannot reliably estimate inter-area modes.

High stress can lead to transient instability due to damping limitations.

Abstract

Fundamental sensor feedback limitations for improving rotor angle stability using local frequency or phase angle measurement are derived. Using a two-machine power system model, it is shown that improved damping of inter-area oscillations must come at the cost of reduced transient stability margins, regardless of the control design method. The control limitations stem from that the excitation of an inter-area mode by external disturbances cannot be estimated with certainty using local frequency information. The results are validated on a modified Kundur four-machine two-area test system where the active power is modulated on an embedded high-voltage dc link. Damping control using local phase angle measurements, unavoidably leads to an increased rotor angle deviation following certain load disturbances. For a highly stressed system, it is shown that this may lead to transient instability. The limitations derived in the paper may motivate the need for wide-area measurements in power oscillation damping control.