Standards Development

Scope

This document specifies minimum performance requirements for the connection of converter -based resources (CBRs) to bulk power systems. It applies to converter -based generation (e.g., photovoltaic and wind power plants), grid-scale energy storage systems, and other converter- interfaced resources operated as grid-connected plants.

Requirements are specified at the interface point(s) of applicability and cover, as a minimum: general connection technical specifications and performance requirements, voltage/reactive -power performance, frequency/active-power performance (including primary and fast frequency response), response to grid abnormal conditions, and power quality.

This document is applicable to newly installed CBRs and to equipment upgrades of existing installations. Market rules and internal equipment design are excluded. Requirements for distribution-level distributed energy resources, grid-forming CBRs and marine energy resources are outside the scope except where explicitly referenced for coordination with other IEC standards.

Purpose

Global power systems are rapidly evolving, increasingly dominated by power electronic converters. In 2024, worldwide energy demand rose by 2.2%, with electricity use surging faster than overall energy use. Converter based resources (CBRs), principally wind , solar and storage, accounted for the largest share of supply growth (≈38%). This drives renewable installations to record levels: an additional 585 GW of capacity was added in 2024, bringing total installed renewable capacity to roughly 4,448 GW (about 46% of global generation capacity). These structural shifts underscore that uniform, transmission level interconnection requirements for large converter -based plants are both timely and necessary. Traditional grid rules were developed for synchronous machin es; as CBRs become dominant, updated standards are needed to ensure bulk power system stability and reliable operations under this new paradigm.

High CBR penetration has also exposed new stability and operability risks at the bulk power system level. Notable real-world disturbances illustrate the vulnerabilities introduced by poorly regulated converter-based resources. ERCOT (Texas), May–June 2021: A normally cleared transmission fault near Odessa, Texas triggered abnormal responses in about 1.1 GW of solar PV capacity. During this Odessa disturbance, many PV inverters momentarily ceased output or tripped, even though the fault was cleared in standard time. Great Britain, 9 August 2019: A lightning-induced fault triggered near-simultaneous outages of a large offshore wind farm (Hornsea One, 737 MW) and a gas -fired plant (Little Barford, 660 MW), along with numerous amounts of smaller distributed gene rators. The sudden loss of 1.4 GW of generation caused the grid frequency to plunge to about 48.8 Hz and led to a nationwide power blackout.

Taken together, these incidents show that rising renewable penetration affects system stability and that existing connection requirements, designed around conventional generation, are no longer sufficient. Clear, standardised rules are needed to specify ho w CBRs must behave at the grid interface under all conditions, covering at a minimum: voltage and reactive power control; frequency and active power response; fault-ride‑through capabilities.

Many developed power systems have already implemented transmission ‑level grid codes or standards for renewable integration (e.g., IEEE Std 2800 ‑2022 in North America [1]; the ENTSO‑E Requirements for Generators network code in Europe [2][3]; national grid codes in Great Britain [4], Australia [5], New Zealand [6] etc.). However, the scope, technical parameters, and performance obligations in these requirements still differ significan tly by region and continue to evolve. This lack of uniformity increases compliance complexity for manufacturers and project developers and hinders efficient cross‑border deployment of renewable generation.

In developing regions (Latin America, Africa, Southeast Asia, etc.), renewables are scaling up rapidly but transmission-level CBR requirements and compliance regimes are often immature. Many emerging economies lack comprehensive grid codes for high convert er penetration, or they are in early stages of drafting guidelines. This “standard gap” leaves fast -growing power systems at risk of repeating the missteps seen elsewhere, without robust connection rules, and new solar and wind farms might not provide essential support (voltage regulation, frequency response) or could trip unpredictably during disturbances. Most importantly, there is currently no IEC standard that provides a common, globally applicable baseline for transmission -level CBR connection.

A harmonized international standard can close these gaps by providing a common baseline of technical requirements drawn from global best practices. Such a standard would reduce technical barriers to entry and simplify compliance requirements. Manufacturers could design equipment to one set of core criteria instead of a patchwork, lowering costs and accelerating technology transfer & advancement.

Recognizing these needs, IEC SC 8A has, since early 2023, been working to develop a harmonized international standard for transmission-level connection of CBRs. JWG 5 has gathered global inputs through multiple rounds of discussions (e.g., meeting in The H ague and Tokyo in 2023; Offenbach in 2024; Kassel in March 2025, Rome in July 2025). Throughout, SC 8A has maintained coordination with ENTSO‑E, IEEE and relative TC/SCs communities to ensure alignment of core concepts and terminology. JWG 5 is advancing a series of PWI projects, including integration requirements for grid-forming CBRs, and the integration of marine energy resources. This propos al, which is one of the principal projects, reflects a broad common understanding to consolidate widely shared requirements into a CBR interface‑focused IEC Technical Specification(TS).