Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee on Wind Power Machinery of Standardization Administration of China (SAC/TC 50).
Wind turbines - Test procedure of voltage fault ride through capability
1 Scope
This standard specifies the technical requirements, test conditions, test items, test requirements, test procedures and test report contents for the voltage fault ride through capability of wind turbine generator units (hereinafter referred to as wind turbines).
This standard is applicable to the grid-connected wind turbines.
2 Normative references
The following referenced documents are indispensable for the application 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.
JJF 1059.1 Evaluation and expression of uncertainty in measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
low voltage ride through capability of wind turbine
capability of the wind turbine that can ensure no disconnection and continuous operation within a certain voltage dip range and time interval in case of voltage dip caused by grid fault or disturbance
3.2
high voltage ride through capability of wind turbine
capability of the wind turbine that can ensure no disconnection and continuous operation within a certain voltage swell range and time interval in case of voltage swell caused by grid fault or disturbance
3.3
voltage fault generator
test equipment that generates a voltage fault with the specifications required by the test at the point of test of wind turbine, based on the principle of impedance/resistance-capacitance division
3.4
point of connection of wind turbine/point of test of wind turbine
point at which the voltage fault generates, which is the connection point between the voltage fault generator and the high voltage side of the step-up transformer of wind turbine
3.5
recovery time of active power
time required from the grid voltage to recover to the normal range, to the output active power of the wind turbine to recover to corresponding output power under the actual wind condition
3.6
voltage dip
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily dips below 0.9p.u. of the nominal voltage of the system and recovers to the normal value range after a short duration
3.7
amplitude of voltage dip
ratio of the minimum line voltage r.m.s. to the system nominal voltage value during a voltage dip, expressed in a per-unit value or percentage
3.8
duration of voltage dip
duration of voltage dip recorded at the set voltage dip threshold
3.9
voltage swell
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily swells above 1.1p.u. of the nominal voltage of the system and recovers to the normal value range after a short duration
3.10
amplitude of voltage swell
ratio of the maximum line voltage r.m.s. to the system nominal voltage value during a voltage swell, expressed in a per-unit value or percentage
3.11
duration of voltage swell
duration of voltage swell recorded at the set voltage swell threshold
3.12
voltage cascading failure
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily dips or swells above 0.9p.u. or 1.1p.u. of the nominal voltage of the system, and rapidly swells or dips to 1.1p.u. or 0.9p.u. after a short duration
3.13
no-load testing
testing for the voltage dip/swell generated by the voltage fault generator at the point of test of wind turbine in the event that the wind turbine is disconnected from the grid
3.14
load testing
testing for the voltage dip/swell generated by the voltage fault generator at the point of test of wind turbine in the event that the wind turbine is connected to the grid
4 Symbols
For the purposes of this document, the following symbols apply.
CL: the capacitance of voltage swell branch.
In: the rated current of wind turbine.
ITL: the r.m.s. of inductive reactive current injection.
ITC: the r.m.s. of capacitive reactive current injection.
P: the active power output of wind turbine.
Pn: the rated power of wind turbine.
Rd: the resistance of voltage swell branch.
Udip: the per-unit value of voltage dip at the point of test of wind turbine.
Upre: the per-unit value of voltage at the point of test of wind turbine before a fault.
Uswell: the per-unit value of voltage swell at the point of test of wind turbine.
UT: the per-unit value of line voltage at the point of test of wind turbine.
Zsr: the current-limiting impedance.
Zsc: the short-circuit impedance.
5 Technical requirements for voltage fault ride through
5.1 Voltage fault curve
Figure 1 is the voltage fault ride through curve for a wind turbine. Where the voltage at the point of connection of wind turbine is above Curve 1 and below Curve 2, the wind turbine is required to operate continuously without disconnection; where the voltage at the point of connection of wind turbine is below Curve 1 or above Curve 2, the wind turbine may be cut out from the grid.
Figure 1 Voltage fault ride through curve for a wind turbine
See Table 1 for the assessment voltages for different voltage fault types.
Table 1 Voltage fault ride through assessment voltages for wind turbine
Voltage fault type Assessment voltage
Three-phase symmetrical voltage fault Line voltage at the point of connection of wind turbine
Three-phase asymmetrical voltage fault Line voltage at the point of connection of wind turbine
5.2 Requirements for voltage fault ride through
The voltage fault ride through of a wind turbine includes low voltage ride through, high voltage ride through and voltage cascading failure. The specific requirements are as follows:
a) for low voltage ride through, the wind turbine shall have the capability of continuous operation without disconnection within the voltage~time range specified in Curve 1 in Figure 1. Requirements are as follows:
1) active power recovery: for wind turbines that have not been disconnected from the grid during voltage dip, the active power shall be recovered to the output power corresponding to the actual wind condition at a power change rate of at least 10% Pn/s from the time when the voltage recovers to normal;
2) dynamic reactive power supporting capability: where a three-phase symmetrical voltage dip occurs at the point of connection of wind turbine, the wind turbine shall respond quickly from the moment when the voltage dip occurs and support voltage recovery by injecting capacitive reactive current. Specific requirements are as follows:
——the response time of dynamic capacitive reactive current control is not greater than 75ms from the moment when the voltage dip occurs at the point of connection of wind turbine, and capacitive reactive current is continuously injected during the voltage fault;
——the dynamic capacitive reactive current provided by the wind turbine shall meet the requirements of Equation (1):
ITC≥1.5×(0.9-UT)In, (0.2≤UT≤0.9) (1)
where a three-phase asymmetrical voltage dip occurs at the point of connection of wind turbine, the wind turbine should be injected with capacitive reactive current to support voltage recovery.
b) for high voltage ride through, the wind turbine shall have the capability of continuous operation without disconnection within the voltage~time range specified in Curve 2 in Figure 1. Requirements are as follows:
1) active power output: for wind turbines that are not disconnected from the grid, the fluctuation amplitude of active power shall be within ±50% Pn at the time of voltage swell and the time of voltage recovering to normal, the fluctuation amplitude shall be greater than zero, and the fluctuation time shall not be greater than 80ms; during voltage swell, the fluctuation amplitude of output active power shall be within ±5％ Pn range; after the voltage recovers to normal, the output power shall be that corresponding to the actual wind condition.
2) dynamic reactive power supporting capability: where a three-phase symmetrical voltage swell occurs at the point of connection of wind turbine, the wind turbine shall respond quickly from the moment when the voltage swell occurs and support voltage recovery by injecting inductive reactive current. Specific requirements are as follows:
——the response time of dynamic inductive reactive current control is not greater than 40ms from the moment when the voltage swell occurs at the point of connection of wind turbine, and inductive reactive current is continuously injected during the voltage fault;
——the dynamic inductive reactive current provided by the wind turbine shall meet the requirements of Equation (2):
ITL≥1.5×(UT-1.1)In, (1.1≤UT≤1.3) (2)
where a three-phase asymmetrical voltage swell occurs at the point of connection of wind turbine, the wind turbine should be injected with inductive reactive current to support voltage recovery.
c) voltage cascading failure test requirements (optional) may be implemented by reference to Annex A.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols 5 Technical requirements for voltage fault ride through 6 Test conditions 7 Test contents 8 Test requirements 9 Test procedures 10 Items of test report Annex A (Informative) Test requirements and test items of voltage cascading failure ride through Annex B (Informative) Measurement of active power, reactive power and voltage Annex C (Informative) Report format sample Annex D (Informative) Methods for judgment and calculation of reactive current injection Bibliography
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China Machinery Industry Federation.
This standard is under the jurisdiction of the National Technical Committee on Wind Power Machinery of Standardization Administration of China (SAC/TC 50).
Wind turbines - Test procedure of voltage fault ride through capability
1 Scope
This standard specifies the technical requirements, test conditions, test items, test requirements, test procedures and test report contents for the voltage fault ride through capability of wind turbine generator units (hereinafter referred to as wind turbines).
This standard is applicable to the grid-connected wind turbines.
2 Normative references
The following referenced documents are indispensable for the application 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.
JJF 1059.1 Evaluation and expression of uncertainty in measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
low voltage ride through capability of wind turbine
capability of the wind turbine that can ensure no disconnection and continuous operation within a certain voltage dip range and time interval in case of voltage dip caused by grid fault or disturbance
3.2
high voltage ride through capability of wind turbine
capability of the wind turbine that can ensure no disconnection and continuous operation within a certain voltage swell range and time interval in case of voltage swell caused by grid fault or disturbance
3.3
voltage fault generator
test equipment that generates a voltage fault with the specifications required by the test at the point of test of wind turbine, based on the principle of impedance/resistance-capacitance division
3.4
point of connection of wind turbine/point of test of wind turbine
point at which the voltage fault generates, which is the connection point between the voltage fault generator and the high voltage side of the step-up transformer of wind turbine
3.5
recovery time of active power
time required from the grid voltage to recover to the normal range, to the output active power of the wind turbine to recover to corresponding output power under the actual wind condition
3.6
voltage dip
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily dips below 0.9p.u. of the nominal voltage of the system and recovers to the normal value range after a short duration
3.7
amplitude of voltage dip
ratio of the minimum line voltage r.m.s. to the system nominal voltage value during a voltage dip, expressed in a per-unit value or percentage
3.8
duration of voltage dip
duration of voltage dip recorded at the set voltage dip threshold
3.9
voltage swell
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily swells above 1.1p.u. of the nominal voltage of the system and recovers to the normal value range after a short duration
3.10
amplitude of voltage swell
ratio of the maximum line voltage r.m.s. to the system nominal voltage value during a voltage swell, expressed in a per-unit value or percentage
3.11
duration of voltage swell
duration of voltage swell recorded at the set voltage swell threshold
3.12
voltage cascading failure
phenomenon that the r.m.s. of the voltage at a certain point in the power system temporarily dips or swells above 0.9p.u. or 1.1p.u. of the nominal voltage of the system, and rapidly swells or dips to 1.1p.u. or 0.9p.u. after a short duration
3.13
no-load testing
testing for the voltage dip/swell generated by the voltage fault generator at the point of test of wind turbine in the event that the wind turbine is disconnected from the grid
3.14
load testing
testing for the voltage dip/swell generated by the voltage fault generator at the point of test of wind turbine in the event that the wind turbine is connected to the grid
4 Symbols
For the purposes of this document, the following symbols apply.
CL: the capacitance of voltage swell branch.
In: the rated current of wind turbine.
ITL: the r.m.s. of inductive reactive current injection.
ITC: the r.m.s. of capacitive reactive current injection.
P: the active power output of wind turbine.
Pn: the rated power of wind turbine.
Rd: the resistance of voltage swell branch.
Udip: the per-unit value of voltage dip at the point of test of wind turbine.
Upre: the per-unit value of voltage at the point of test of wind turbine before a fault.
Uswell: the per-unit value of voltage swell at the point of test of wind turbine.
UT: the per-unit value of line voltage at the point of test of wind turbine.
Zsr: the current-limiting impedance.
Zsc: the short-circuit impedance.
5 Technical requirements for voltage fault ride through
5.1 Voltage fault curve
Figure 1 is the voltage fault ride through curve for a wind turbine. Where the voltage at the point of connection of wind turbine is above Curve 1 and below Curve 2, the wind turbine is required to operate continuously without disconnection; where the voltage at the point of connection of wind turbine is below Curve 1 or above Curve 2, the wind turbine may be cut out from the grid.
Figure 1 Voltage fault ride through curve for a wind turbine
See Table 1 for the assessment voltages for different voltage fault types.
Table 1 Voltage fault ride through assessment voltages for wind turbine
Voltage fault type Assessment voltage
Three-phase symmetrical voltage fault Line voltage at the point of connection of wind turbine
Three-phase asymmetrical voltage fault Line voltage at the point of connection of wind turbine
5.2 Requirements for voltage fault ride through
The voltage fault ride through of a wind turbine includes low voltage ride through, high voltage ride through and voltage cascading failure. The specific requirements are as follows:
a) for low voltage ride through, the wind turbine shall have the capability of continuous operation without disconnection within the voltage~time range specified in Curve 1 in Figure 1. Requirements are as follows:
1) active power recovery: for wind turbines that have not been disconnected from the grid during voltage dip, the active power shall be recovered to the output power corresponding to the actual wind condition at a power change rate of at least 10% Pn/s from the time when the voltage recovers to normal;
2) dynamic reactive power supporting capability: where a three-phase symmetrical voltage dip occurs at the point of connection of wind turbine, the wind turbine shall respond quickly from the moment when the voltage dip occurs and support voltage recovery by injecting capacitive reactive current. Specific requirements are as follows:
——the response time of dynamic capacitive reactive current control is not greater than 75ms from the moment when the voltage dip occurs at the point of connection of wind turbine, and capacitive reactive current is continuously injected during the voltage fault;
——the dynamic capacitive reactive current provided by the wind turbine shall meet the requirements of Equation (1):
ITC≥1.5×(0.9-UT)In, (0.2≤UT≤0.9) (1)
where a three-phase asymmetrical voltage dip occurs at the point of connection of wind turbine, the wind turbine should be injected with capacitive reactive current to support voltage recovery.
b) for high voltage ride through, the wind turbine shall have the capability of continuous operation without disconnection within the voltage~time range specified in Curve 2 in Figure 1. Requirements are as follows:
1) active power output: for wind turbines that are not disconnected from the grid, the fluctuation amplitude of active power shall be within ±50% Pn at the time of voltage swell and the time of voltage recovering to normal, the fluctuation amplitude shall be greater than zero, and the fluctuation time shall not be greater than 80ms; during voltage swell, the fluctuation amplitude of output active power shall be within ±5％ Pn range; after the voltage recovers to normal, the output power shall be that corresponding to the actual wind condition.
2) dynamic reactive power supporting capability: where a three-phase symmetrical voltage swell occurs at the point of connection of wind turbine, the wind turbine shall respond quickly from the moment when the voltage swell occurs and support voltage recovery by injecting inductive reactive current. Specific requirements are as follows:
——the response time of dynamic inductive reactive current control is not greater than 40ms from the moment when the voltage swell occurs at the point of connection of wind turbine, and inductive reactive current is continuously injected during the voltage fault;
——the dynamic inductive reactive current provided by the wind turbine shall meet the requirements of Equation (2):
ITL≥1.5×(UT-1.1)In, (1.1≤UT≤1.3) (2)
where a three-phase asymmetrical voltage swell occurs at the point of connection of wind turbine, the wind turbine should be injected with inductive reactive current to support voltage recovery.
c) voltage cascading failure test requirements (optional) may be implemented by reference to Annex A.
Contents of GB/T 36995-2018
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols
5 Technical requirements for voltage fault ride through
6 Test conditions
7 Test contents
8 Test requirements
9 Test procedures
10 Items of test report
Annex A (Informative) Test requirements and test items of voltage cascading failure ride through
Annex B (Informative) Measurement of active power, reactive power and voltage
Annex C (Informative) Report format sample
Annex D (Informative) Methods for judgment and calculation of reactive current injection
Bibliography
