Sensor/actuator colocation feasibility for distributed damping control using active power modulation

Abstract

Multi-use distributed active power modulation devices, including energy storage, have the potential to transform the dynamic performance and resilience of modern power systems. Rapid response characteristics relative to traditional power delivery equipment paired with traditional uses (arbitrage, reserve, etc.) make storage an obvious choice for multi-use operation, adding value for asset owners while augmenting stability for reliable operation. Limitations to distributed power control are investigated to provide guidance for those interested in separated sensors and actuators. Substantive distance between the sensor/actuator pair results in non-minimum phase (NMP) which complicates the control design, reducing feedback system effectiveness. It is shown that wide-area control (WAC) is limited by the presence of NMP induced by closed right-half plane (CRHP) zeros - a consequence of sensors placed at locations separated from modulation bus(es). Such geographic separation may be driven by economics, asset owner jurisdiction, technology and/or policy, and is therefore unavoidable. This work suggests that system designers must perform a collocation study before control design and testing. A well-known WAC architecture using synchrophasors as sensors and energy storage devices for active power injection is presented as a detailed case study. • Collocated sensor–actuators pose difficulties which may force modest separation. • Closed right-half plane (CRHP) zeros may result due to such separation. • Noncollocated sensor–actuator pairs may reduce performance and threaten stability. • Bandwidth and performance limitations regarding collocation are determined.