ISO 22266-1-2022 PDF

Full title and description

ISO 22266-1:2022 — Mechanical vibration — Torsional vibration of rotating machinery — Part 1: Evaluation of steam and gas turbine generator sets due to electrical excitation. This International Standard provides guidelines for assessing torsional natural frequencies and shaft-component strength of coupled turbine-generator shaft trains when exposed to electrical (grid) excitation.

Abstract

This document gives procedures and acceptance guidance for evaluating torsional natural frequencies and component strength, under normal operating conditions, for coupled shaft trains (including long elastic rotor blades) of land‑based steam and gas turbine generator sets connected to an electrical network. It covers torsional responses at the system’s grid (line) frequency and at twice the grid frequency due to electrical excitation of the network. The standard describes analytical assessment methods and test‑validation approaches. It does not address torsional excitation caused by steam forces or other non‑electrical excitation mechanisms.

General information

• Status: Published (current).
• Publication date: 18 May 2022 (corrected English version: August 2022).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 17.160 (Vibration, shock and vibration measurement); 29.160.40 (Generating sets).
• Edition / version: Edition 2 (2022).
• Number of pages: 38 pages.

Scope

ISO 22266-1:2022 applies to land‑based steam and gas turbine generator sets connected to an electrical network. It gives guidance for the assessment of torsional natural frequencies and component strength of the coupled shaft train, including long elastic rotor blades, under normal operating conditions. The standard specifically addresses torsional responses at the grid (line) frequency and at twice the grid frequency caused by electrical excitation from the power system. It excludes torsional vibration effects arising from steam excitation or other excitation mechanisms not related to the electrical network. Where shaft sections, couplings or natural frequencies fail to meet the strength or frequency margin criteria, the document requires defining remedial actions.

Key topics and requirements

• Identification and assessment of torsional natural frequencies of coupled turbine‑generator shaft trains.
• Evaluation of component strength and torsional stress under electrical excitation at line and twice‑line frequencies.
• Guidance on acceptable frequency margins and criteria for determining non‑conformance.
• Analytical methods for modal and torsional response estimation (modeling approaches for shaft trains and long elastic rotor blades).
• Recommended test methods and procedures for validation of analytical predictions (test validation during commissioning or troubleshooting).
• Requirements to define corrective actions (design changes, operational limits, damping or other mitigations) when criteria are not met.
• Explicit exclusions: steam excitation and other non‑electrical excitation mechanisms are not covered.

Typical use and users

ISO 22266-1:2022 is used by rotating‑machinery and rotor‑dynamics engineers, turbine and generator OEMs, power‑plant commissioning teams, utilities, independent consultants, vibration specialists, and test laboratories. Typical applications include design verification, acceptance testing, commissioning checks, condition assessment following modifications, and failure‑mode analysis where electrical network excitation could excite torsional modes.

Related standards

Relevant and complementary documents include the withdrawn predecessor ISO 22266-1:2009 (superseded by this edition) and standards on vibration measurement and evaluation for large turbines and generators (for example the ISO 20816 series). Other rotor‑dynamics and machine‑vibration standards used together with ISO 22266-1 include standards covering measurement practice, alarm/trip criteria and in‑situ vibration evaluation for turbine/generator installations.

Keywords

torsional vibration; rotating machinery; shaft train; turbine-generator; steam turbine; gas turbine; electrical excitation; grid frequency; twice-line frequency; natural frequency; rotor dynamics; modal analysis; test validation; component strength; ISO 22266-1:2022.

FAQ

Q: What is this standard?

A: ISO 22266-1:2022 is an international standard that provides guidelines for evaluating torsional natural frequencies and the torsional strength of coupled turbine-generator shaft trains when subjected to electrical (power‑system) excitation.

Q: What does it cover?

A: It covers assessment methods (analytical and test validation), acceptance criteria and remedial actions for torsional vibration responses at the grid (line) frequency and at twice the grid frequency for land‑based steam and gas turbine generator sets connected to an electrical network. It does not cover torsional excitation by steam forces or other non‑electrical mechanisms.

Q: Who typically uses it?

A: Turbine and generator OEMs, design and rotor‑dynamics engineers, plant commissioning and maintenance teams, vibration consultants, and test laboratories involved with large land‑based steam and gas turbine generator sets.

Q: Is it current or superseded?

A: It is current. ISO 22266-1:2022 (Edition 2) was published on 18 May 2022 with a corrected English version issued in August 2022. It supersedes and replaces ISO 22266-1:2009.

Q: Is it part of a series?

A: Yes — ISO 22266 is a multi‑part topic on torsional vibration of rotating machinery; this document is Part 1 and relates conceptually to other ISO standards on machine vibration measurement and evaluation (for example the ISO 20816 series) that address radial/axial vibration and broader vibration measurement practice.

Q: What are the key keywords?

A: Torsional vibration; rotating machinery; turbine-generator; electrical excitation; grid frequency; twice‑line frequency; shaft train; rotor dynamics; modal analysis; test validation; component strength.