Transformer and Reactor Procurement

Description

This Green Book provides those involved in transformer procurement with comprehensive guidance on industry best practice to avoid wrong decisions. Transformers are one of the expensive components in the power system, and also contribute a large proportion of the losses. Transformers also have long lives - more than 40 years in many cases. Making the wrong decisions during the procurement process can have serious and long-lasting consequences.  Foreword CIGRE and Transformer Procurement Transformer Procurement in the Future Acknowledgments Contents About the Editors Contributors 1 Overview of Transformer and Reactor Procurement 1 Introduction 2 Terminology 3 Overview of the Procurement Process 4 Structure of This Green Book 4.1 Tender Process 4.2 Identification of Functional Requirements, Specifications, Sound Levels, and Loss and Efficiency 4.3 Supplier Qualification and Development 4.4 Project Management 4.5 Project Execution at the Factory 4.6 Transport and Storage 4.7 Installation, Pre-Commissioning, and Trial Operation References 2 Tender Process for Transformers 1 Introduction 2 Step 1 (Internal Preparation) 2.1 Formation of Multifunctional Team 2.2 Tasks for the Multifunctional Team 2.3 Identification of User Technical Expectations and Requirements 2.4 Identification of User Commercial Expectations and Requirements 2.5 Market Surveys 2.6 Forecast 3 Step 2 (Supplier Selection or Qualification) 3.1 Request for Information 3.2 Evaluation of Information Provided 3.3 Factory Capability Assessments 3.4 Selection Criteria 4 Step 3 (Tendering and Contract Awarding) 4.1 Invitation to Tender 4.2 Tender Submission 4.3 Tender Evaluation 4.4 Negotiations 4.5 Award 5 Step 4 (Contract Implementation) 6 Step 5 (Follow-Up and Evaluation) References 3 Identification of Functional Requirements for Transformers and Shunt Reactors 1 Overview for Power Transformers 2 Functional Requirements for Power Transformers 3 Identification of Rated Quantities 3.1 Autotransformers 3.2 Tertiary Windings 3.3 Reconnectable Transformers 4 Loading 4.1 Unbalance and Neutral Point Loading 4.2 Harmonics 5 Taps and Voltage Regulation 6 Network Requirements 6.1 General Description of Network 6.2 Method of Network Earthing 6.3 Insulation Co-ordination 6.4 Insulation Co-ordination for HVDC Transformers 6.5 Impedance 6.6 Parallel Operation 6.7 Short-Circuit Withstand Capability 7 Cooling and the Effect of Ambient Conditions 7.1 Cooling Modes 7.2 Temperature Rise Limits 8 Other Unusual Operational Requirements for Transformers 8.1 Over-Excitation 8.2 DC Magnetization 8.3 Unusual Energization Conditions 8.4 Direct Connection to Gas-Insulated Switchgear 9 Overview for Reactors 9.1 Recent Developments in Shunt Reactors 9.2 Auxiliary Windings 9.3 Linearity 10 Functional Requirements for Shunt Reactors References 4 Specifications for Transformers and Reactors - Design and Construction 1 Introduction 2 Specification of Design and Construction Requirements 2.1 Specifications and Standards 2.2 Specifications and Guidance to the Supplier 3 Purpose of the Transformer or Reactor 3.1 Site Information 4 Design Concept 4.1 Design Concepts for Power Transformers 4.2 Design Concepts for Shunt Reactors 4.3 Single-Phase and Three-Phase Designs 5 Cores 6 Windings and Connections 6.1 Types of Conductor Material 6.2 Types of Conductor 6.3 Types of Winding 6.4 Joining Conductors 6.5 Mechanical Strength 7 Solid Insulation 7.1 Insulation Samples (Degree of Polymerization) 7.2 Insulation Samples (Moisture) 8 Liquid Insulation 9 Tank or Enclosure 9.1 Fire and Explosion Safety 9.2 Safe Systems for Working at Heights 9.3 Lid-Type or Bell-Type 9.4 Method of Closing Flange 9.5 Earthing 9.6 Valves 9.7 Corrosion Protection 9.8 Lifting and Handling Facilities 9.9 Access Openings 10 Gaskets and Seals 11 Liquid Preservation System References 5 Specifications - Components and Fittings 1 Introduction 2 Specification of Requirements for Components and Fittings 2.1 Specifications and Standards 2.2 Specifications and Guidance to the Supplier 3 Coolers 3.1 Radiators 3.2 Fans 3.3 Pumps 3.4 Compact Air/Liquid Heat Exchangers 3.5 Compact Water/Liquid Heat Exchangers 4 Terminations 4.1 Bushings 4.1.1 Rated Characteristics 4.1.2 Dielectric Withstand Levels 4.1.3 Operating Conditions 4.1.4 External Clearances 4.1.5 Creepage 4.1.6 Provision for Internal Current Transformers 4.1.7 Internal Insulation 4.1.8 Envelope 4.1.9 Through Conductor 4.1.10 Test and Potential Taps 4.1.11 Compatibility 4.2 Plug-In Bushings 4.3 Cable Box 5 Current Transformers 6 Taps and Tap-Changers 6.1 Rated Characteristics 6.2 Dielectric Withstand Levels 6.3 Switching 6.4 Transition Impedance 6.5 Mounting 7 Internal Surge Arresters 8 Other Fittings 8.1 Liquid and Winding Temperatures Indicators 8.2 Gas and Liquid Operated Relays 8.3 Pressure Relief Devices 8.4 Rapid Pressure Rise Relay 8.5 Liquid Level Indicators 8.6 Liquid Flow Indicators 8.7 Rating Plate 8.8 Valve Plate 8.9 Safety Labels 8.10 Condition Monitoring Equipment and Facilities 9 Auxiliary Supplies, Auxiliary Wiring, Terminal Boxes, Control Cabinets 9.1 Auxiliary Supplies 9.2 Auxiliary Wiring 9.3 Terminal Boxes 9.4 Control Cabinet References 6 Specification of Sound Levels for Transformers and Reactors 1 Introduction 2 Origins of Transformer Sound Level 3 Origins of Shunt Reactor Sound 4 Characterization of Sound Levels 4.1 Listener Response 5 Controlling Sound Levels 5.1 Transformer and Reactor Design 5.2 External Measures 6 Specification of Sound Levels 6.1 Sound Pressure; Sound Intensity; Sound Power 6.2 Tolerance 6.3 Transformers 6.4 Shunt Reactors 7 Typical Sound Levels for Specification Purposes 7.1 Background 7.2 No-Load Sound Levels for Transformers 7.3 Load Sound Levels for Transformers 7.4 Sound Levels for Shunt Reactors References 7 Transformer Losses and Efficiency 1 Transformer Losses 2 Controlling Losses 3 Methods for Specifying Transformer Losses 3.1 Use of Fixed Losses 3.2 Use of Minimum Efficiency 3.3 Use of Peak Efficiency Index (PEI) 3.4 Use of Loss Capitalization in a Total Cost of Ownership Approach 4 Impact of Capitalization Values on Transformer Design, Losses, and the Environment 5 Overview of Capitalization Formula and Main Components 5.1 No-Load Loss Capitalization Factor (A) 5.2 Load Loss Capitalization Factor (B) 5.3 Relationship Between No-Load Losses and Load Losses in Transformer Selection 5.4 Use of A and B Values in a Transformer Tender 6 Derivation of the Capitalization Factors 6.1 No-Load Capitalisation Factors (A) 6.2 Load Capitalization Factors (B) 6.3 Sensitivity Analysis 7 Selection of Input Parameters Values 7.1 Marginal Price of Electricity (C0) 7.1.1 Marginal Price of Losses Under High Levels of Renewable Penetration 7.2 Discount Rates 7.2.1 Risk Adjusted Cost of Capital 7.2.2 Use of Societal Discount Rates 7.3 Price Growth (g) 7.4 Load Growth (v) 7.5 Useful Economic Life of the Transformer (n) 8 Worked Examples 8.1 Summary of Derivation of Utility Transformer Loss Capitalization Factors 8.2 Summary of Derivation of Non-Utility Transformer Loss Capitalization Factors for Private Company References 8 Transformer and Reactor Supplier Selection 1 Introduction 2 Design Concept and Documentation 2.1 Introduction 2.2 Different Insulation Systems 2.3 Different Design Concepts for Transformers 2.4 Different Design Concepts for Shunt Reactors 2.5 Origins of Technology; License Agreements 2.6 Reference List 2.7 Familiarity with Different Standards 2.8 Documentation 3 Engineering 3.1 Design Documentation, Software, and Process Flow 3.2 Design Calculation Methods 3.2.1 Magnetizing Characteristics 3.2.2 Sound Level and Vibration 3.2.3 Load Loss and Impedance 3.2.4 Dielectric Design 3.2.5 Thermal Design 3.2.6 Short Circuit Withstand Capability 3.2.7 Mechanical Design 4 Supply Chain Management 5 Manufacturing 6 Testing 7 Transport 8 Installation and Pre-Commissioning 9 Warranty and Service 10 Project Management 11 Quality Management 12 Environmental Management 12.1 Dangerous Materials 13 Human Resources, and Health and Safety Management 13.1 Human Resources 13.1.1 Introduction 13.1.2 Legal and Cultural Aspects 13.1.3 Industrial Relations 13.1.4 Recruitment 13.1.5 Training 13.1.6 Vulnerable Workers 13.2 Working Environment 13.2.1 Welfare Facilities 13.2.2 Working Hours 13.2.3 Holidays 13.2.4 Security 13.3 Health and Safety References 9 Transformer and Reactor Project Management 1 Introduction 2 Project Manager and Project Team 2.1 Languages 3 Contract Review 3.1 Objectives 3.2 Pre-Award Contract Review 3.3 Initial Post-Award Contract Review 3.4 Review of Agreed Contract Documents 4 General Requirements for Project Documentation 4.1 Size, Format, and Languages 4.2 Document Submission Schedule 4.3 Review of Drawings and Documents 4.3.1 Reviewed 4.3.2 Reviewed with Corrections Indicated 4.3.3 Rejected and Returned for Correction 4.4 Document Management System 5 Requirements for Specific Project Drawings and Documents 5.1 Scope of Project Drawings and Documents 5.2 Manufacturing Program 5.3 Design Review Report 5.4 Customer Drawings 5.5 Quality Plan 5.6 Factory Test Documentation 5.7 Transport Documentation 5.8 Installation and Pre-Commissioning Documentation 5.9 Operation and Maintenance Manuals 6 Design Review 6.1 Basic Objectives 6.2 Internal Design Review 6.3 Preparation by the User 6.4 Additional Objectives 6.5 Scheduling and Organization 7 Follow-Up During Production and Test 7.1 Use of the Quality Plan 7.2 Sample Testing 7.3 Submission of Records and Reports 7.4 Inspections of Work-in-Progress 8 Final Review on Completion 8.1 Purpose 8.2 Lessons Learned Discussion References 10 Transformer Design Using Advanced Methods 1 Introduction 2 Information for Design Review 3 Electrical Characteristics, Mass, and Dimensions 3.1 Magnetizing Characteristics 3.2 Sound Level and Vibration 3.3 Load Loss and Impedance 3.4 Internal Reactors and Surge Arrestors 3.5 Connection Diagram 3.6 Mass and Dimensions 4 Dielectric Design 4.1 Transient Over-Voltages 4.2 Fundamentals of Dielectric Design 4.3 High Frequency Modelling 4.4 Major Insulation Design 4.5 Minor Insulation Design 4.6 Lead Insulation Design 4.7 Tap-changer Selection 4.8 Material Properties 5 Thermal Design 5.1 Fundamentals of Thermal Design 5.2 Thermal Modelling 5.3 Direct Hot-Spot Temperature Measurements 5.4 Dynamic Thermal Performance 5.5 High-Temperature Liquid-Immersed Transformer Design 6 Short-Circuit Withstand Capability 6.1 Fundamentals 6.2 Calculations 7 Mechanical Design 8 Special Considerations for HVDC Converter Transformers References 11 Transformer and Reactor Manufacturing 1 Introduction 2 Quality 2.1 Training and Certification of Workers 3 Production Environment 3.1 Handling and Moving 4 Production Planning and Warehouse 5 Cores 5.1 Design Concepts 5.2 Slitting and Cutting 5.3 Stacking 5.4 Inspections 6 Windings, Insulation 6.1 Design Concepts 6.2 Conducting Materials 6.3 Conductor Production 6.4 Insulating Materials 6.5 Insulation Component Production 6.6 Winding Production 6.7 Inspections 7 Winding Dryout, Sizing, and Assembly 7.1 Winding Dryout and Sizing 7.2 Inspections 8 Steel Fabrications 8.1 Cutting; Assembly; Welding 8.2 Cleaning, Painting 8.3 Inspections 9 Core and Winding Assembly 9.1 Winding Nesting 9.2 Connections 9.3 Inspections 10 Final Dryout 10.1 Final Dryout Process 10.2 Finishing After Final Dryout 10.3 Inspections 11 Final Assembly 11.1 Scope 11.2 Liquid Filling 11.3 Inspections References 12 Transformer and Reactor Testing - Introduction and Performance Tests 1 Transformer and Reactor Testing 1.1 Introduction 1.2 Classification of Tests 1.3 Required Tests 1.4 Are Type Tests Needed on a Specific Transformer? 1.4.1 When Is a Type Test a Routine Test 1.5 Waiving Tests on a Specific Transformer 1.6 Tests on Major Components 1.7 Calibration of Test Equipment Used 1.8 Accuracy and Uncertainty 1.9 Specification of Test Requirements 1.9.1 Permission to Test 1.9.2 Test Witnessing 1.9.3 Documentation 1.9.4 Assembly for Test 1.9.5 Provision of Test Results 1.9.6 Correction Factors 1.9.7 Test Certificate 1.9.8 Complex Calculations 1.10 Action in Case of a Non-Conformance or Failure 1.11 Summary of Tests 2 Details of Electrical Tests 2.1 Measurement of Winding Resistance 2.1.1 Description 2.1.2 Methodology 2.1.3 Applicability 2.1.4 Acceptance Criteria 2.1.5 Challenges 2.2 Measurement of Voltage Ratio 2.2.1 Description 2.2.2 Methodology 2.2.3 Applicability 2.2.4 Acceptance Criteria 2.2.5 Challenges 2.3 Check of Phase Displacement 2.3.1 Description 2.3.2 Methodology 2.3.3 Applicability 2.3.4 Acceptance Criteria 2.3.5 Challenges 2.4 Measurement of Short-Circuit Impedance and Load Loss 2.4.1 Description 2.4.2 Methodology 2.4.3 Measuring Equipment 2.4.4 Applicability 2.4.5 Acceptance Criteria 2.4.6 Challenges 2.5 Measurement of No-Load Loss and Current 2.5.1 Description 2.5.2 Methodology 2.5.3 Applicability 2.5.4 Acceptance Criteria 2.5.5 Challenges 2.6 Measurement of Zero Sequence Impedance 2.6.1 Description 2.6.2 Methodology 2.6.3 Applicability 2.6.4 Acceptance Criteria 2.6.5 Challenges 2.7 On-Load Tap-Changer Operation 2.7.1 Description 2.7.2 Methodology 2.7.3 Applicability 2.7.4 Acceptance Criteria 2.7.5 Challenges 2.8 Current Transformer Checks 2.8.1 Description 2.8.2 Methodology 2.8.3 Applicability 2.8.4 Acceptance Criteria 2.8.5 Challenges 2.9 Determination of Sound Levels 2.9.1 Description 2.9.2 Methodology 2.9.3 Applicability 2.9.4 Acceptance Criteria 2.9.5 Challenges 2.10 Measurement of Winding Frequency Response 2.10.1 Description 2.10.2 Methodology 2.10.3 Applicability 2.10.4 Acceptance Criteria 2.10.5 Challenges 2.11 Liquid Sampling 2.12 Short-Circuit Withstand Test 3 Details of Additional Electrical Tests for Shunt Reactors 3.1 Losses; Reactance; Linearity 3.1.1 Description 3.1.2 Methodology 3.1.3 Applicability 3.1.4 Acceptance Criteria 3.1.5 Challenges 3.2 Vibration 3.2.1 Description 3.2.2 Methodology 3.2.3 Applicability 3.2.4 Acceptance Criteria 3.2.5 Challenges 4 Details of Mechanical Tests 4.1 Pressure Deflection Test 4.1.1 Methodology 4.1.2 Applicability 4.1.3 Acceptance Criteria 4.1.4 Challenges 4.2 Vacuum Deflection Test 4.2.1 Methodology 4.2.2 Applicability 4.2.3 Acceptance Criteria 4.2.4 Challenges 4.3 Pressure Tightness Test 4.3.1 Methodology 4.3.2 Applicability 4.3.3 Acceptance Criteria 4.3.4 Challenges 4.4 Vacuum Tightness Test 4.4.1 Methodology 4.4.2 Applicability 4.4.3 Acceptance Criteria 4.4.4 Challenges References 13 Transformer and Reactor Testing: Temperature Rise 1 Temperature Rise and Associated Cooler Operation 1.1 Description 1.2 Methodology 1.2.1 Test Methods 1.2.2 Tapped Windings and Tap Position 1.2.3 Measurement of Liquid and Ambient Temperatures 1.2.4 Determination of Liquid Temperature Rise 1.2.5 Internal Temperature Measurement Requirements 1.2.6 Short Circuit Method 1.2.7 Winding Resistance Measurements After Shutdown 1.2.8 Determination of Average Winding Temperature Rise 1.2.9 Determination of the Average Winding to Liquid Temperature Gradient 1.2.10 Correction Factors and Calculations Applied to Measured Temperatures 1.2.11 Use of Infrared Thermography 1.2.12 Use of Dissolved Gas Analysis 1.3 Applicability of the Test 1.4 Acceptance Criteria for the Test 1.5 Challenges 2 Testing of Multi-Winding Transformers 2.1 Separate Winding Transformer, with Two LV Windings of Equal Rated Power and Voltage 2.2 Separate Winding Transformer, with Two LV Windings of Unequal Rated Power or Voltage 2.3 Separate Winding Transformer, with Additional LV Winding of Low Rated Power 3 Testing of Autotransformers 3.1 Tapped Windings and Tap Position 3.2 Winding Resistance Measurements After Shutdown 3.3 Tertiary Winding Brought Out for Loading 4 Hot Spot Temperature Rise Determination 5 Measurement of Power Taken by Fans and Pumps 5.1 Methodology 5.2 Applicability of the Test 5.3 Acceptance Criteria for the Test 5.4 Challenges 6 Temperature Non-conformance References 14 Transformer and Reactor Testing - Dielectric Tests 1 Dielectric Tests 2 Individual Dielectric Tests 2.1 Lightning Impulse Tests 2.1.1 Description 2.1.2 Methodology 2.1.3 Applicability 2.1.4 Acceptance Criteria 2.1.5 Challenges 2.2 Lightning Impulse Tests, with Internal Surge Arrestors 2.2.1 Description 2.2.2 Applicability 2.2.3 Acceptance Criteria 2.2.4 Challenges 2.3 Switching Impulse Tests 2.3.1 Description 2.3.2 Methodology 2.3.3 Applicability 2.3.4 Acceptance Criteria 2.3.5 Challenges 2.4 Applied Voltage Test, on Windings 2.4.1 Description 2.4.2 Methodology 2.4.3 Applicability 2.4.4 Acceptance Criteria 2.4.5 Challenges 2.5 Applied Voltage Test, on Auxiliary Circuits, and Test Loops 2.5.1 Description 2.5.2 Methodology 2.5.3 Applicability 2.5.4 Acceptance Criteria 2.5.5 Challenges 2.6 Line Terminal AC Withstand Test 2.6.1 Description 2.6.2 Methodology 2.6.3 Applicability 2.6.4 Acceptance Criteria 2.6.5 Challenges 2.7 Induced Voltage Tests 2.7.1 Induced Voltage Withstand Test 2.7.1.1 Description 2.7.1.2 Methodology 2.7.1.3 Applicability 2.7.1.4 Acceptance Criteria 2.7.1.5 Challenges 2.7.2 Induced Voltage Test, with Partial Discharge Measurements 2.7.2.1 Description 2.7.2.2 Methodology 2.7.2.3 Applicability 2.7.2.4 Acceptance Criteria 2.7.2.5 Challenges 2.8 Insulation Resistance 2.8.1 Description 2.8.2 Methodology 2.8.3 Applicability 2.8.4 Acceptance Criteria 2.8.5 Challenges 2.9 Capacitance and Dielectric Dissipation Factor 2.9.1 Description 2.9.2 Methodology 2.9.3 Applicability 2.9.4 Acceptance Criteria 2.9.5 Challenges 3 Dielectric Tests for Shunt Reactors 3.1 Induced Voltage Tests on Shunt Reactors 3.1.1 Description 3.1.2 Methodology 3.1.3 Applicability 3.1.4 Acceptance Criteria 3.1.5 Challenges 4 Additional Dielectric Tests for HVDC Transformers and Reactors 4.1 Applied Switching Impulse Test 4.1.1 Description 4.1.2 Methodology 4.1.3 Applicability 4.1.4 Acceptance Criteria 4.1.5 Challenges 4.2 DC Applied Voltage Test 4.2.1 Description 4.2.2 Methodology 4.2.3 Applicability 4.2.4 Acceptance Criteria 4.2.5 Challenges 4.3 AC Applied Voltage Test 4.3.1 Description 4.3.2 Methodology 4.3.3 Applicability 4.3.4 Acceptance Criteria 4.3.5 Challenges 4.4 Polarity Reversal Test 4.4.1 Description 4.4.2 Methodology 4.4.3 Applicability 4.4.4 Acceptance Criteria 4.4.5 Challenges 4.5 Extended Polarity Reversal Test 4.5.1 Description 4.5.2 Methodology 4.5.3 Applicability 4.5.4 Acceptance Criteria 4.5.5 Challenges References 15 Transformer and Reactor Transport 1 Introduction 2 Specifications and Design Review 2.1 Feasibility Studies 3 Delivery Terms 3.1 Incoterms Rules 3.2 Incoterms Rules and Power Transformers 4 Different Transport Modes 4.1 Road 4.2 Rail 4.3 Water 4.4 Air 4.5 Summary 5 Shock Recorders 6 Transport Planning and Transport Documentation 6.1 Transport Safety 6.2 Transport Drawing 6.3 Transport Markings 7 Inspection on Receipt References 16 Transformer and Reactor Storage 1 Introduction 2 Storage for Different Lengths of Time 2.1 Dry-Type Transformers 3 Preparation for Storage 3.1 Storage Without Liquid 3.2 Storage Partly Assembled, with Liquid 3.3 Storage Fully Assembled, with Liquid 4 Maintenance During Storage 4.1 Acceptance Criteria for Checks 5 Storage of Components and Materials 5.1 Bushings 5.2 Coolers 5.3 Other Components References 17 Transformer and Reactor Installation 1 Introduction 2 Terminology 3 Preparation 3.1 Documentation 3.2 Environmental, Health, and Safety Management 3.3 Checking of the Work Site 3.4 Workers and Equipment 4 Overview 5 Checks on Receipt 6 Assembly 6.1 Earthing 6.2 Unpacking 6.3 Assembly of Turrets 6.4 Assembly of Coolers 6.5 Assembly of Conservator 6.6 Assembly of Bushings 6.7 Assembly of Other Components 6.8 Wiring and Cabling 7 Liquid Filling 7.1 Scope 7.2 Receipt 7.3 Storage and Handling 7.4 Filling 7.5 Circulation 7.6 Standing Time References 18 Transformer and Reactor Pre-Commissioning 1 Introduction 2 Terminology 3 Aims 4 Scope 4.1 Visual Inspection and Functional Checks 4.2 Electrical Tests 4.2.1 Individual Tests 4.3 Liquid Tests 4.3.1 Liquid Tests for Oil-Immersed Transformers and Reactors 4.3.2 Liquid Tests for Ester-Immersed Transformers and Reactors 4.3.3 Liquid Tests for Silicone Immersed Transformers References 19 Trial Operation for Transformers and Reactors 1 Introduction 2 Terminology 3 Aims 4 Warranty Scope and Duration 4.1 Duration of the Warranty Period 5 First Energization 6 First Loading 7 Operation During the Warranty Period 7.1 Trends in Dissolved Gas in Trial Operation 8 End of the Warranty Period References