Islanding Detection (Active vs Passive)
Techniques to detect an unintentional “island” where a site keeps energizing a local grid segment after it is disconnected from the main grid.
Technical Details
ISO 15118-20 includes a parameter to indicate which islanding detection method is used: passive detection (monitoring grid conditions) or active detection (injecting disturbances to test for islanding). Detection interacts with grid codes and with grid-forming behavior in bidirectional operation.
Fleet Applications
Critical for safe and compliant bidirectional charging: affects approvals with DSOs, protection settings, and whether a depot can support backup power without unsafe islanding.
Related Terms
Vehicle-to-Grid (V2G)
Bidirectional charging technology that enables electric vehicles to return digitally managed energy from their batteries back to the power grid during peak demand periods.
ISO 15118 (Plug & Charge)
Family of standards for high-level communication between an electric vehicle (EV) and a charging station (EVSE), enabling certificate-based "Plug & Charge" and advanced charging control (including bidirectional charging in newer editions).
Bidirectional Power Transfer (BPT)
ISO 15118 concept for charging and discharging where an EV and EVSE coordinate power flow in both directions (V2G/V2B), not just charging.
Generator Mode (Grid-Following vs Grid-Forming)
ISO 15118-20 BPT parameter describing the inverter behavior during discharge: following the grid voltage/frequency (grid-following) or actively forming them (grid-forming).
Smart Grid
A modernized electricity grid that uses digital control and two-way communication to balance supply and demand.