Standard Specs for PCS: UFR/OFR & Frequency Feedback

This document, published by the Japan Electrical Manufacturers' Association, provides standard specifications for power conditioning systems (PCS) in the new energy industry, serving as a design guideline. It covers UFR/OFR settings for FRT-compatible models, including settable frequency levels and time delays. The core focus is the frequency feedback method with step injection for active islanding detection, detailing gain slope recommendations to prevent flicker, adjustable reactive power injection proportional to active power, and variable maximum injection types. Revisions across eight editions (2020-2025) add flicker countermeasures, rated output error, allowable frequency during parallel operation, and case studies on islanding and PCS operation issues. The document aims to standardize specifications not fully described in regulations like the Grid Interconnection Code, promoting consistency while allowing flexibility for new product development.