IEC TR 60909-4-2021 PDF

Full title and description

Short‑circuit currents in three‑phase AC systems — Part 4: Examples for the calculation of short‑circuit currents (IEC TR 60909‑4:2021). This Technical Report provides worked examples and modelling guidance to support application of IEC 60909‑0 for calculating short‑circuit currents in 50 Hz and 60 Hz three‑phase systems.

Abstract

IEC TR 60909‑4:2021 (Edition 2.0) is a guidance document (technical report) that does not introduce new mandatory requirements but gives practical examples and detailed modelling advice for positive‑, negative‑ and zero‑sequence representations of equipment, worked examples for low‑ and medium‑voltage systems (including asynchronous motors), a power‑station unit example, and a new wind‑power example. It also includes a high‑voltage test network and reference results intended for verification of computer programs. The 2021 edition replaces the 2000 edition and aligns the examples with IEC 60909‑0:2016.

General information

• Status: Valid (Technical Report, edition 2.0).
• Publication date: Approved 24 June 2021 (published 2021).
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 17.220.01 (Electricity, magnetism — general aspects); 29.240.20 (Power transmission and distribution lines).
• Edition / version: Edition 2.0 (2021).
• Number of pages: 80 pages.

Scope

This Technical Report is intended to help users apply IEC 60909‑0 for calculation of short‑circuit currents in 50 Hz or 60 Hz three‑phase AC systems. It provides guidance for sequence‑system modelling (positive, negative and zero), worked examples for practical calculations in low‑voltage systems, medium‑voltage systems with asynchronous motors, a power‑station unit with auxiliary networks, and an added example covering wind power station units. It also supplies a test network with data and reference results for software validation.

Key topics and requirements

• Worked examples illustrating IEC 60909‑0 calculation procedures (low‑voltage, medium‑voltage, power‑station unit, wind‑power plant).
• Modelling advice for positive‑, negative‑ and zero‑sequence impedances of equipment (transformers, lines, reactors, generators, motors).
• Comparison and verification data: high‑voltage test network (380 kV / 110 kV / 30 kV / 10 kV) with reference calculation results for software validation.
• Examples demonstrating calculation methods (per‑unit, absolute, superposition) and techniques for handling asynchronous motor contributions and converter‑based generation.
• No new prescriptive requirements — the report clarifies application of IEC 60909‑0 and contains corrections and adaptations from the previous (2000) edition.

Typical use and users

Engineers and specialists performing short‑circuit studies, protection and coordination engineers, power‑system consultants, utility planning teams, switchgear manufacturers and software developers use this TR as a worked‑example reference and verification aid when applying IEC 60909‑0 methods (including connections with wind and converter‑based generation). It is particularly useful for validating calculation software against reference cases and for training/education in short‑circuit calculation techniques.

Related standards

Main related documents are IEC 60909‑0 (Calculation of currents; latest significant edition 2016), IEC TR 60909‑1 (factors), IEC TR 60909‑2 (equipment data), IEC 60909‑3 (earth/partial short‑circuit cases) and the earlier IEC TR 60909‑4:2000 which this 2021 edition replaces. Users should consult IEC 60909‑0:2016 when applying methods described in this TR.

Keywords

short‑circuit currents; three‑phase AC systems; IEC 60909; worked examples; sequence modelling; positive sequence; negative sequence; zero sequence; asynchronous motors; wind power; software validation; power‑station unit.

FAQ

Q: What is this standard?

A: IEC TR 60909‑4:2021 is a Technical Report (guidance document) titled "Short‑circuit currents in three‑phase AC systems — Part 4: Examples for the calculation of short‑circuit currents" that provides worked examples and modelling guidance for applying IEC 60909‑0.

Q: What does it cover?

A: It covers practical calculation examples (low‑voltage, medium‑voltage, power‑station unit), sequence impedance modelling for equipment, a wind‑power example added in 2021, and a high‑voltage test network with reference results to validate calculation programs. It is not a new normative requirements document but a companion for IEC 60909‑0.

Q: Who typically uses it?

A: Power‑system and protection engineers, grid planners, consultants, switchgear manufacturers, and developers of short‑circuit calculation software — anyone who needs worked examples and verification cases when applying IEC 60909‑0 methods.

Q: Is it current or superseded?

A: The 2021 edition (Edition 2.0) replaces the 2000 edition. As of its publication it is the current IEC TR for Part 4; users should verify against any later amendments or revisions published by IEC.

Q: Is it part of a series?

A: Yes — it is Part 4 of the IEC 60909 series (Short‑circuit currents in three‑phase AC systems). The series includes IEC 60909‑0 (calculation rules) and companion parts/TRs providing factors, equipment data and special cases.

Q: What are the key keywords?

A: Short‑circuit currents, IEC 60909, worked examples, sequence impedance, wind power, validation test network, asynchronous motors, protection engineering.