IEC 62256:2008

Hydraulic turbines, storage pumps and pump-turbines - Rehabilitation and performance improvement

Provides assistance in identifying, evaluating and executing rehabilitation and performance improvement projects for hydraulic turbines, storage pumps and pump-turbines of all sizes and of the following types: Francis; Kaplan; Propeller; Pelton (turbines only); Bulb.

Turbines hydrauliques, pompes d'accumulation et pompes turbines - Réhabilitation et amélioration des performances

Fournir une aide à l'identification, à l'évaluation et à l'exécution de projets de réhabilitation et d'amélioration des performances de turbines hydrauliques, de pompes d'accumulation et de pompes-turbines de toutes tailles et des types suivants: Francis; Kaplan; hélice; Pelton (turbines seulement); bulbe.

General Information

• Status: Published
• Publication Date: 14-Jan-2008
• ICS: 27.140 - Hydraulic energy engineering
• Technical Committee: TC 4 - Hydraulic turbines
• Drafting Committee: WG 26 - TC 4/WG 26
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 30-May-2017

Relations

• Revised: IEC 62256:2017 - Hydraulic turbines, storage pumps and pump-turbines - Rehabilitation and performance improvement
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62256
Edition 1.0 2008-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Hydraulic turbines, storage pumps and pump-turbines – Rehabilitation and
performance improvement
Turbines hydrauliques, pompes d'accumulation et pompes turbines –
Réhabilitation et amélioration des performances

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IEC 62256
Edition 1.0 2008-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Hydraulic turbines, storage pumps and pump-turbines – Rehabilitation and
performance improvement
Turbines hydrauliques, pompes d'accumulation et pompes turbines –
Réhabilitation et amélioration des performances

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XF
CODE PRIX
ICS 27.140 ISBN 2-8318-9332-1
– 2 – 62256 © IEC:2008
CONTENTS
FOREWORD.6
INTRODUCTION.8

1 Scope and object.9
2 Nomenclature .9
3 Reasons for rehabilitating.10
3.1 General .10
3.2 Reliability and availability increase .12
3.3 Life extension and performance restoration .13
3.4 Performance improvement.13
3.5 Plant safety improvement .13
3.6 Environmental, social and regulatory issues .13
3.7 Maintenance and operating cost reduction.14
3.8 Other considerations .14
4 Phases of a rehabilitation project.14
4.1 General .14
4.2 Decision on organization .16
4.2.1 General .16
4.2.2 Expertise required .16
4.2.3 Contract arrangement.17
4.3 Level of assessment and determination of scope.17
4.3.1 General .17
4.3.2 Feasibility study – Stage 1.18
4.3.3 Feasibility study – Stage 2.18
4.3.4 Detailed study .18
4.4 Contractual issues.24
4.4.1 General .24
4.4.2 Specification requirements .24
4.4.3 Tendering documents and evaluation of tenders.24
4.4.4 Contract Award(s).25
4.5 Execution of project.25
4.5.1 Model test activities.25
4.5.2 Design, construction, installation and testing .26
4.6 Evaluation of results and compliance with guarantees .26
4.6.1 General .26
4.6.2 Turbine performance evaluation .27
4.6.3 Generator performance evaluation.27
4.6.4 Penalties and/or bonuses assessment.27
5 Scheduling, cost analysis and risk analysis .27
5.1 Scheduling .27
5.1.1 General .27
5.1.2 Scheduling – Assessment, feasibility and detailed study phases.28
5.1.3 Evaluating the scheduling component of alternatives .28
5.1.4 Scheduling specification and tendering phase .29
5.1.5 Scheduling project execution phases .30
5.2 Economic and financial analyses.30

62256 © IEC:2008 – 3 –
5.2.1 General .30
5.2.2 Benefit-cost analysis .31
5.2.3 Identification of anticipated benefits.32
5.2.4 Identification of anticipated costs and benefits.33
5.2.5 Sensitivity analysis .34
5.2.6 Conclusions.35
5.3 Risk analysis .35
5.3.1 General .35
5.3.2 Non-achievement of performance risk.36
5.3.3 Risk of continued operation without rehabilitation .36
5.3.4 Extension of outage risk .36
5.3.5 Financial risks .37
5.3.6 Project scope risk .37
5.3.7 Other risks.38
6 Assessment and determination of scope of the work.38
6.1 General .38
6.2 Assessment of the site .39
6.2.1 Hydrology .39
6.2.2 Actual energy production .39
6.2.3 Environmental social and regulatory issues .40
6.3 The assessment of the turbine .41
6.3.1 General .41
6.3.2 Turbine integrity assessment .70
6.3.3 Residual life .79
6.3.4 Turbine performance assessment .80
6.4 The assessment of related equipment .102
6.4.1 General .102
6.4.2 Generator and thrust bearing.107
6.4.3 Turbine governor .109
6.4.4 Turbine inlet and outlet valves, pressure relief valve. 109
6.4.5 Auxiliary equipment .109
6.4.6 Equipment for erection, dismantling and maintenance . 110
6.4.7 Penstock and other water passages .110
6.4.8 Consequences of changes in plant specific hydraulic energy (head).111
7 Hydraulic design and performance testing options .111
7.1 General .111
7.2 Computational hydraulic design. 112
7.2.1 General .112
7.2.2 The role of CFD.
...