Stability Analysis and HIL Validation of PV Park Voltage Control Considering Communication Delays

With advances in industrial data communication technologies, MW-scale PV parks increasingly depend on communication-based coordination among Power Electronic Converters (PECs) to ensure precise voltage regulation and stability, especially during grid fault events. However, Communication Delay (CD) can degrade voltage control, leading to sustained oscillations and Transient Overvoltage (TOV) during post-fault recovery. This paper analyzes the impact of such delays on PV park stability under a centralized secondary voltage controller (SecVC) and proposes a local control strategy to enhance coordination robustness to CDs. A nonlinear model of a PV park is built and used for small-signal stability analysis, incorporating Monte-Carlo Simulations (MCS) to assess the impact of stochastic delays, alongside time-domain simulations to evaluate dynamic responses. The proposed approach is validated through Hardware-in-the-Loop (HIL) testing, using two HIL devices interfaced via a communication network emulator (CNE) with the Modbus-TCP protocol.