Integrated Autonomous Voltage Regulation and Islanding Detection for High Penetration PV Applications

Abstract

This paper proposes an autonomous unified var controller to address the system voltage issues and unintentional islanding problems associated with distributed Photovoltaic (PV) generation systems. The proposed controller features integration of both voltage regulation (VR) and islanding detection (ID) functions in a PV inverter based on reactive power control. Compared with the individual VR or ID methods, the function integration exhibits several advantages in high PV penetration applications: 1) fast voltage regulation due to the autonomous control; 2) enhanced system reliability because of the capability to distinguish between temporary grid disturbances and islanding events; 3) negligible non-detection zone (NDZ) and no adverse impact on system power quality for ID and 4) no interferences among multiple PV systems during ID. As the VR and ID functions are integrated in one controller, the controller is designed to fulfill the requirement of VR dynamic performance and ensure small ID NDZ simultaneously. The interaction among multiple PV systems during VR is also considered in the design procedure. Finally, the feasibility of the proposed controller and the controller design method is validated with simulation using a real time digital simulator (RTDS) and a power hardware-in-the-loop (PHIL) testbed.

Implementation and validation of advanced unintentional islanding testing using power hardware-in-the-loop (PHIL) simulation

“…Instead, an emerging approach is to test one or more ICSs by connecting them to a software-simulated distribution system model, which may also include other ICSs. This mixed fullpower hardware and software simulation approach, often called power hardware-in-the-loop (PHIL), has been used extensively to test many complex systems including small (<10 kW) [5], [6], [7], and large (500 kW) [8] grid-connected PV inverters, PV/super capacitor systems for power quality control [9], a microgrid-connected STATic synchronous COMpensator [10], and EPS-connected motor drives at the 25 kVA [11] and 5 MVA [12] power levels.…”

“…The methodology of utilizing PHIL to complete unintentional islanding testing for an ICS has been previously suggested in [13] and implemented in [7], however a clear analysis and validation of this PHIL-based method against typical discrete hardware methods has yet to be completed. This paper describes the implementation, experimental results, and validation against discrete hardware methods of PHILbased unintentional islanding testing that was completed at the National Renewable Energy Laboratory (NREL).…”

Noise attenuation motivated controller design. Part II: Position control

“…[5]- [8]), in motion control, but also in many other fields, as e.g. power electronics, the constrained design represents an active and important area of research.…”

Photovoltaic penetration issues and impacts in distribution network – A review

“…Therefore, typical studies are carried out to investigate possible adverse impacts on the power quality, protection coordination and operation of distribution feeders. These investigations also examine the interactions of distribution equipment such as on load tap changers and status of capacitor banks [6]. Therefore, increasing penetration of PV in distribution level applies more stress on the utility voltage regulation devices and can even cause them to malfunction.…”