Wind energy generation systems - Electrical characteristics measurement and assessment of wind turbines
1 Scope
This document specifies the definition, measurement procedures and evaluation methods for the electrical characteristics parameters of wind turbines. It includes:
——definition and specification of the quantities to be determined for characterizing the electrical characteristics of a grid-connected wind turbine;
——measurement procedures for quantifying the electrical characteristics;
——procedures for assessing compliance with electrical connection requirements, including estimation of the power quality expected from the wind turbine type when deployed at a specific site.
The measurement procedures are valid for single wind turbines with a three-phase grid
connection. The measurement procedures are valid for any size of wind turbine, though this document only requires wind turbine types intended for connection to an electricity supply network to be tested and characterized as specified in this document.
The measured characteristics are valid for the specific configuration and operational mode of the assessed wind turbine product platform. If a measured property is based on control parameters and the behavior of the wind turbine can be changed for this property, it is stated in the test report. Example: Grid protection, where the disconnect level is based on a parameter and the test only verifies the proper functioning of the protection, not the specific level.
The measurement procedures are designed to be as non-site-specific as possible, so that electrical characteristics measured at for example a test site can be considered representative for other sites.
This document applies to wind turbines that stabilize the grid by combining frequencies at common connection points.
Note: For the purposes of this document, the following terms for system voltage apply:
——Low voltage (LV) refers to Un ≤ 1 kV;
——Medium voltage (MV) refers to 1 kV < Un ≤ 35 kV;
——High voltage (HV) refers to 35 kV < Un ≤ 220 kV;
——Extra high voltage (EHV) refers to Un > 220 kV.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.
IEC TR 61000-3-7 Electromagnetic compatibility (EMC) - Part 3-7: Limits - Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems
IEC 61 000-4-7:2002/AMD1:2008 Electromagnetic compatibility (EMC) - Part 4-7: Testing and measurement techniques - General guide on harmonics and interharmonics measurements and instrumentation, for power supply systems and equipment connected thereto
IEC 61000-4-15:201 0
Electromagnetic compatibility (EMC) - Part 4-15: Testing and measurement techniques - Flickermeter - Functional and design specifications
IEC 61000-4-30 Electromagnetic compatibility (EMC) - Part 4-30: Testing and measurement techniques - Power quality measurement methods
IEC 61869-103 Instrument transformers - The use of instrument transformers for power quality measurement
IEC 62008 Performance characteristics and calibration methods for digital data acquisition systems and relevant software
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
continuous operation
normal operation of the wind turbine excluding switching operations
3.2
cut-in wind speed
lowest wind speed at hub height at which the wind turbine starts to produce power
[SOURCE: IEC 60050-41 5:1 999, 41 5-03-05]
3.3
disconnection time
time duration from exceeding a predefined disconnection level until the physical disconnection of the wind turbine from the grid
3.4
flicker coefficient for continuous operation
c( ψk )
normalized measure of the flicker emission during continuous operation of the wind turbine
3.5
flicker step factor
kf ( ψk )
normalized measure of the flicker emission due to a single switching operation of the wind
Turbine
3.6
maximum measured power
highest measured value of active power (with a specified averaging time) that is observed during continuous operation of the wind turbine
3.7
network impedance phase angle
Ψk
phase angle of network short-circuit impedance
3.8
normal operation
fault free operation according to the description in the wind turbine manual
3.9
operational mode
operation according to control setting, for example voltage control mode, frequency control mode, reactive power control mode, active power control mode, etc.
3.10
output power
electric active power delivered by the wind turbine at its terminals
[SOURCE: GB/T 2900.53-2001, 2.4.2, modified.]
3.11
point of common coupling
PCC
point of a power supply network, electrically nearest to a particular load, at which other loads may be connected
Note 1: These loads can be devices, equipment or systems, or distinct customer's installations.
Note 2: In some applications, the term "point of common coupling" is restricted to public networks.
[SOURCE: GB/T 4365-2003, 2.7, modified.]
3.12
power collection system
electrical system that collects the power from a wind turbine and feeds it into an electrical
supply network
[SOURCE: GB/T 2900.53-2001,2.4.6, modified.]
