Wind energy generation systems - Technical specifications for post-evaluation and retrofitting of wind farms
1 Scope
This document specifies the technical requirements related to the post-evaluation and retrofitting of wind farms (hereinafter referred to as “wind farms”), including the requirements for conducting post-evaluation, post-design evaluation of wind farms, post-operation evaluation of wind farms, as well as the technical requirements and evaluation for wind farm retrofitting aimed at optimizing energy production and improving reliability.
This document is applicable to the post-evaluation of onshore wind farms that have been put into operation and have generated operational data, as well as to the design evaluations for technical retrofitting aimed at optimizing energy production and improving reliability of these wind farms. It may serve as a reference for offshore wind farms.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 5226.1 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements
GB/T 15969.1 Programmable controllers - Part 1: General information
GB/T 15969.2 Programmable controllers - Part 2: Equipment requirements and tests
GB/T 18451.1 Wind energy generation systems - Design requirements
GB/T 18451.2-2021 Wind turbines - Power performance measurements of electricity producing
GB/T 19963.1 Technical specification for connecting wind farm to power system - Part 1: On shore wind power
GB/T 33225 Electricity producing wind turbines - Power performance measurements based on nacelle anemometry
GB/T 37523-2019 Specification for data inspection and correction of wind power plant meteorological observation
DL/T 1870 Technical specification for power grid and source coordination
NB/T 10103-2018 Technical code for micro-siting of wind power projects
NB/T 10205 Technical rules for wind power forecasting
NB/T 10590 Technical specification of lightning protection improvement for power grid in wind farms located in multiple thunderstorm region
NB/T 10909 Wind energy resources analysis and output calculation methods for micrositing
NB/T 31046 Function specification of wind power forecasting system
NB/T 31078 Evaluation method for grid code compliance of wind farms
NB/T 31085 Code for economic evaluation of wind farm
IEC 61400-26-1 Wind energy generation systems - Part 26-1: Availability for wind energy generation systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
reanalysis of meteorological data
use of long-term consistent meteorological observation data, applying data assimilation and atmospheric numerical model systems to generate long-term, continuous data with higher spatial and temporal resolution to describe atmospheric conditions
[Source: GB/T 37523-2019, 3.2, modified]
3.2
nacelle wind speed
horizontal wind speed measured on top of the nacelle of a wind turbine or in front of a wind turbine
[Source: GB/T 33225-2016, 3.21]
3.3
nacelle transfer function
functional relationship between nacelle wind speed and the wind speed measured by the anemometer of anemometer tower at the hub height of the turbine, used to correct the nacelle wind speed to the far upstream free-stream wind speed
3.4
power curve conformance
ratio of the cumulative value of actual power for each wind speed interval multiplied by the measured wind frequency (or specified wind frequency) to the cumulative value of theoretical power (or guaranteed power) for each wind speed interval multiplied by the measured wind frequency (or specified wind frequency) across all wind speed intervals of a single wind turbine, also known as the power curve guarantee value
Note 1: For multiple turbines, it is the arithmetic average of the power curve guarantee values for the turbines.
Note 2: Power curve conformance is generally also referred to as power curve compliance, and power curve guarantee value is commonly referred to as power curve assessment value in contracts.
3.5
actual energy production
energy measured at the point of connection of the wind turbine to the power collection system
Note: The connection point may be at low voltage level or at medium or high voltage level depending on the design of the wind turbine. For IEC 61400-26-1, it is defined as the actual service delivery, i.e., the actual measurement value at the connection point of the wind farm.
[Source: GB/Z 35483-2017, 3.1.2, modified]
3.6
potential energy production
calculated energy based on the wind turbine design criteria and technical specifications and the site conditions
Note: For IEC 61400-26-1, it is defined as potential service delivery), i.e., the calculated value of physical potential output or restricted potential output.
[Source: GB/Z 35483-2017, 3.1.3, modified]
3.7
lost production
energy that the wind turbine should have generated but failed to generated
Note: The lost production is the difference between potential energy production and actual energy production. For IEC 61400-26-1, it is defined as lost service, i.e., unprovided service.
[Source: GB/Z 35483-2017, 3.1.4, modified]
3.8
design theoretical energy production
annual theoretical energy production determined during the wind farm design stage, using the turbine's contract power curve, measured topographical maps, and preliminary wind measurement data as inputs, with wind resource assessment and consideration of various reductions and losses
3.9
automatic generation control; AGC
control process that automatically adjusts the active power output of each generator, wind farm, and photovoltaic station within a control area, using an automatic control program to maintain system frequency and the power exchange of the interconnection lines within planned target ranges
[Source: DL/T 1870-2018, 3.4]
3.10
levelized cost of energy
discounted ratio of all costs incurred by the wind farm power generation system during the evaluation period to the total amount of energy available for grid connection
Note: It is expressed in CNY per kilowatt-hour kilowatt-hour (kWh).
3.11
supervisory control and data acquisition; SCADA
system based on a processor unit which receives information from intelligent electric device (IED), determines the control requirements and sends commands to the IED
Note: A computer system that for example dispatchers use to monitor the power distribution throughout a service or control area. For the purpose of this document, it specifically refers to the centralized control system for all wind turbines and their ancillary equipment within the wind farm.
[Source: GB/T 30966.1-2022, 3.32]
3.12
baseline evaluation period
time period used for baseline comparison before wind turbine retrofitting
3.13
optimized evaluation period
time period used for evaluation after wind turbine retrofitting and stable operation
3.14
test turbines
wind turbines undergoing technological upgrades during the optimized evaluation period
3.15
reference turbines
wind turbines that have not undergone technological upgrades during the optimized evaluation period and are used to evaluate the improvement effects of the test turbines
4 Abbreviations
For the purposes of this document, the following abbreviations apply.
IRR: Internal Rate of Return
LCOE: Levelized Cost of Energy
NPV: Net Present Value
PBA: Production-based Availability
PPD: Power Performance Deviation
TBA: Time-based Availability
VG: Vortex Generator
Contents
Foreword III
Introduction IV
1 Scope
2 Normative references
3 Terms and definitions
4 Abbreviations
5 Evaluation requirements
5.1 General
5.2 Data integrity
5.3 Data normalization
5.4 Data classification
6 Post-design evaluation of wind farms
6.1 General
6.2 Representativeness of anemometer towers
6.3 Turbine selection and configuration
6.4 Topography
6.5 Wind resource
6.6 Deviation in energy production
6.7 Economical efficiency
7 Post-operation evaluation of wind farms
7.1 General
7.2 Power generation performance
7.3 Availability
7.4 Reliability
7.5 Safety
7.6 Grid-connected operation
7.7 Economical efficiency
8 Retrofitting of wind farms
8.1 General
8.2 Optimization
8.3 Component installation and replacement
8.4 Complete machine replacement
8.5 Others
9 Evaluation of wind farm retrofitting
9.1 General
9.2 Retrofit effectiveness
9.3 Safety
9.4 Economical efficiency
10 Requirements for report
Annex A (Informative) Data collection checklist
Annex B (Normative) Wind speed normalization
Annex C (Informative) Empirical method for solving nacelle transfer function
Annex D (informative) Evaluation of related parameters and typical abnormal conditions of turbine power generation performance
Bibliography
Wind energy generation systems - Technical specifications for post-evaluation and retrofitting of wind farms
1 Scope
This document specifies the technical requirements related to the post-evaluation and retrofitting of wind farms (hereinafter referred to as “wind farms”), including the requirements for conducting post-evaluation, post-design evaluation of wind farms, post-operation evaluation of wind farms, as well as the technical requirements and evaluation for wind farm retrofitting aimed at optimizing energy production and improving reliability.
This document is applicable to the post-evaluation of onshore wind farms that have been put into operation and have generated operational data, as well as to the design evaluations for technical retrofitting aimed at optimizing energy production and improving reliability of these wind farms. It may serve as a reference for offshore wind farms.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 5226.1 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements
GB/T 15969.1 Programmable controllers - Part 1: General information
GB/T 15969.2 Programmable controllers - Part 2: Equipment requirements and tests
GB/T 18451.1 Wind energy generation systems - Design requirements
GB/T 18451.2-2021 Wind turbines - Power performance measurements of electricity producing
GB/T 19963.1 Technical specification for connecting wind farm to power system - Part 1: On shore wind power
GB/T 33225 Electricity producing wind turbines - Power performance measurements based on nacelle anemometry
GB/T 37523-2019 Specification for data inspection and correction of wind power plant meteorological observation
DL/T 1870 Technical specification for power grid and source coordination
NB/T 10103-2018 Technical code for micro-siting of wind power projects
NB/T 10205 Technical rules for wind power forecasting
NB/T 10590 Technical specification of lightning protection improvement for power grid in wind farms located in multiple thunderstorm region
NB/T 10909 Wind energy resources analysis and output calculation methods for micrositing
NB/T 31046 Function specification of wind power forecasting system
NB/T 31078 Evaluation method for grid code compliance of wind farms
NB/T 31085 Code for economic evaluation of wind farm
IEC 61400-26-1 Wind energy generation systems - Part 26-1: Availability for wind energy generation systems
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
reanalysis of meteorological data
use of long-term consistent meteorological observation data, applying data assimilation and atmospheric numerical model systems to generate long-term, continuous data with higher spatial and temporal resolution to describe atmospheric conditions
[Source: GB/T 37523-2019, 3.2, modified]
3.2
nacelle wind speed
horizontal wind speed measured on top of the nacelle of a wind turbine or in front of a wind turbine
[Source: GB/T 33225-2016, 3.21]
3.3
nacelle transfer function
functional relationship between nacelle wind speed and the wind speed measured by the anemometer of anemometer tower at the hub height of the turbine, used to correct the nacelle wind speed to the far upstream free-stream wind speed
3.4
power curve conformance
ratio of the cumulative value of actual power for each wind speed interval multiplied by the measured wind frequency (or specified wind frequency) to the cumulative value of theoretical power (or guaranteed power) for each wind speed interval multiplied by the measured wind frequency (or specified wind frequency) across all wind speed intervals of a single wind turbine, also known as the power curve guarantee value
Note 1: For multiple turbines, it is the arithmetic average of the power curve guarantee values for the turbines.
Note 2: Power curve conformance is generally also referred to as power curve compliance, and power curve guarantee value is commonly referred to as power curve assessment value in contracts.
3.5
actual energy production
energy measured at the point of connection of the wind turbine to the power collection system
Note: The connection point may be at low voltage level or at medium or high voltage level depending on the design of the wind turbine. For IEC 61400-26-1, it is defined as the actual service delivery, i.e., the actual measurement value at the connection point of the wind farm.
[Source: GB/Z 35483-2017, 3.1.2, modified]
3.6
potential energy production
calculated energy based on the wind turbine design criteria and technical specifications and the site conditions
Note: For IEC 61400-26-1, it is defined as potential service delivery), i.e., the calculated value of physical potential output or restricted potential output.
[Source: GB/Z 35483-2017, 3.1.3, modified]
3.7
lost production
energy that the wind turbine should have generated but failed to generated
Note: The lost production is the difference between potential energy production and actual energy production. For IEC 61400-26-1, it is defined as lost service, i.e., unprovided service.
[Source: GB/Z 35483-2017, 3.1.4, modified]
3.8
design theoretical energy production
annual theoretical energy production determined during the wind farm design stage, using the turbine's contract power curve, measured topographical maps, and preliminary wind measurement data as inputs, with wind resource assessment and consideration of various reductions and losses
3.9
automatic generation control; AGC
control process that automatically adjusts the active power output of each generator, wind farm, and photovoltaic station within a control area, using an automatic control program to maintain system frequency and the power exchange of the interconnection lines within planned target ranges
[Source: DL/T 1870-2018, 3.4]
3.10
levelized cost of energy
discounted ratio of all costs incurred by the wind farm power generation system during the evaluation period to the total amount of energy available for grid connection
Note: It is expressed in CNY per kilowatt-hour kilowatt-hour (kWh).
3.11
supervisory control and data acquisition; SCADA
system based on a processor unit which receives information from intelligent electric device (IED), determines the control requirements and sends commands to the IED
Note: A computer system that for example dispatchers use to monitor the power distribution throughout a service or control area. For the purpose of this document, it specifically refers to the centralized control system for all wind turbines and their ancillary equipment within the wind farm.
[Source: GB/T 30966.1-2022, 3.32]
3.12
baseline evaluation period
time period used for baseline comparison before wind turbine retrofitting
3.13
optimized evaluation period
time period used for evaluation after wind turbine retrofitting and stable operation
3.14
test turbines
wind turbines undergoing technological upgrades during the optimized evaluation period
3.15
reference turbines
wind turbines that have not undergone technological upgrades during the optimized evaluation period and are used to evaluate the improvement effects of the test turbines
4 Abbreviations
For the purposes of this document, the following abbreviations apply.
IRR: Internal Rate of Return
LCOE: Levelized Cost of Energy
NPV: Net Present Value
PBA: Production-based Availability
PPD: Power Performance Deviation
TBA: Time-based Availability
VG: Vortex Generator
Contents of GB/T 44681-2024
Contents
Foreword III
Introduction IV
1 Scope
2 Normative references
3 Terms and definitions
4 Abbreviations
5 Evaluation requirements
5.1 General
5.2 Data integrity
5.3 Data normalization
5.4 Data classification
6 Post-design evaluation of wind farms
6.1 General
6.2 Representativeness of anemometer towers
6.3 Turbine selection and configuration
6.4 Topography
6.5 Wind resource
6.6 Deviation in energy production
6.7 Economical efficiency
7 Post-operation evaluation of wind farms
7.1 General
7.2 Power generation performance
7.3 Availability
7.4 Reliability
7.5 Safety
7.6 Grid-connected operation
7.7 Economical efficiency
8 Retrofitting of wind farms
8.1 General
8.2 Optimization
8.3 Component installation and replacement
8.4 Complete machine replacement
8.5 Others
9 Evaluation of wind farm retrofitting
9.1 General
9.2 Retrofit effectiveness
9.3 Safety
9.4 Economical efficiency
10 Requirements for report
Annex A (Informative) Data collection checklist
Annex B (Normative) Wind speed normalization
Annex C (Informative) Empirical method for solving nacelle transfer function
Annex D (informative) Evaluation of related parameters and typical abnormal conditions of turbine power generation performance
Bibliography
