Mixed Voltage Angle and Frequency Droop Control for Transient Stability of Interconnected Microgrids with Loss of PMU Measurements
For microgrid operators, this addresses the practical problem of PMU measurement loss, but the solution is incremental as it combines existing droop control methods.
The paper proposes a mixed voltage angle and frequency droop control (MAFD) framework to guarantee transient stability of interconnected microgrids when PMU measurements are lost. The approach uses frequency droop as a fallback and a dissipativity-based secondary control to ensure stability under arbitrary switching, demonstrated on a 123-feeder network.
We consider the problem of guaranteeing transient stability of a network of interconnected angle droop controlled microgrids, where voltage phase angle measurements from phasor measurement units (PMUs) may be lost, leading to poor performance and instability. In this paper, we propose a novel mixed voltage angle and frequency droop control (MAFD) framework to improve the reliability of such angle droop controlled microgrid interconnections. In this framework, when the phase angle measurement is lost at a microgrid, conventional frequency droop control is temporarily used for primary control in place of angle droop control. We model the network of interconnected microgrids with the MAFD architecture as a nonlinear switched system. We then propose a dissipativity-based distributed secondary control design to guarantee transient stability of this network under arbitrary switching between angle droop and frequency droop controllers. We demonstrate the performance of this control framework by simulation on a test 123-feeder distribution network.