Method for operating a wind turbine
A method for operating a wind turbine configured to supply electrical power to an electrical power supply network via a converter comprises measuring a phase angle and measuring a voltage of the electrical power supply network. A value of at least one parameter for a phase locked loop is determined depending on the measured voltage. The phase locked loop is used to determine a corrected phase angle depending on the measured phase angle and the voltage of the electrical power supply network. The corrected phase angle is input into the converter.
1. A method for operating a wind turbine configured to supply electrical power to an electrical power supply network via a converter, the method comprising:
measuring a phase angle and measuring a voltage of the electrical power supply network;
determining a value of at least one parameter for a phase locked loop depending on the measured voltage;
adjusting for a network error, wherein the network error comprises a voltage drop to a value of 15% of nominal value or less;
using the phase locked loop to determine a corrected phase angle depending on the measured phase angle and the measured voltage of the electrical power supply network; and
inputting the corrected phase angle into the converter.
2. The method according to claim 1 , wherein the at least one parameter determines dynamics of the phase locked loop.
3. The method according to claim 2 , wherein the at least one parameter is configured to slow the dynamics if the measured voltage is low.
4. The method according to claim 3 , wherein the at least one parameter assumes a value such that the phase locked loop holds the corrected phase angle at an almost constant value if the measured voltage is below a threshold value.
5. The method according to claim 1 , further comprising a proportional loop filter, wherein the at least one parameter is a proportionality constant K P , and wherein a value of the proportionality constant is determined in a voltage-dependent manner.
6. The method according to claim 5 , further comprising a low-pass filter, wherein the at least one parameter is a time constant T 1 , and wherein a value of time constant is determined in a voltage-dependent manner.
7. The method according to claim 6 , wherein dynamics of the phase locked loop are determined in a voltage-dependent manner by at least one of the proportionality constant Kp and the time constant T 1 .
8. The method according to claim 6 , wherein the proportionality constant K P assumes a value of almost zero when there is a network error.
9. The method according to claim 8 , wherein the value of the time constant T 1 is considerably increased when there is a network error.
10. The method according to claim 6 , further comprising a dead-time element having an adjustable dead time Tt.
11. The method according to claim 1 , wherein the at least one parameter is specified as a continuous function depending on the voltage.
12. The method according to claim 11 , wherein the value of the at least one parameter progresses in a voltage-dependent manner between a minimum value and a maximum value.
13. The method according to claim 1 , wherein the voltage is a positive sequence voltage.
14. The method according to claim 1 , wherein the voltage is a negative sequence voltage.
15. The method according to claim 1 , wherein the corrected phase angle is determined in a continuous manner.
16. The method according to claim 1 , further comprising setting the at least one parameter of the phase locked loop.