Wind energy installation with negative sequence system regulation and operating method
View Patent ↗A wind energy installation can include a generator which is driven by a rotor and generates electrical power in a multiphase manner for feeding into a network, a converter which is connected to the generator and to the network, and a control system which interacts with the converter and includes a negative sequence system regulation mechanism. The negative sequence system regulation mechanism can include a phase control module configured to determine an electrical variable of the negative sequence system according to the phase. Accordingly, an available current can be provided according to the operating situation for active power or idle power in the negative sequence system regulation mechanism. The negative sequence system regulation mechanism can thus help stabilize the network in the event of asymmetrical network conditions. Also, this relates to a correspondingly equipped wind park and an operating method.
1. A wind energy installation comprising:
a generator which is driven by a rotor and generates electrical power in a polyphase manner for feeding into a grid;
a converter connected to the generator and the grid;
a controller which interacts with the converter and comprises a negative phase sequence system regulation mechanism, the negative phase sequence system regulation mechanism comprising a phase control module configured to determine an electrical variable of a negative phase sequence system in a phase-specific manner; and
a priority module that directs the controller to feed in as much active current as possible in a positive phase sequence system during normal operation and to selectively supply reactive current in the positive and negative phase sequence system if a fault situation in the grid is identified, depending on the balanced and unbalanced components of the voltage that occurs.
2. The wind energy installation of claim 1 , wherein the negative phase sequence system regulation mechanism comprises an active power regulator.
3. The wind energy installation of claim 2 , wherein the active power regulator of the negative phase sequence system regulation mechanism has a desired value input, to which a value equal to zero is applied.
4. The wind energy installation of claim 1 , 2 , or 3 , wherein the negative phase sequence system regulation mechanism comprises a reactive power regulator.
5. The wind energy installation of claim 4 , wherein the reactive power regulator has a desired value input, to which a value not equal to zero is applied.
6. The wind energy installation of claim 5 , further comprising a power observer configured to determine at least one of an available power and an available current depending on the loading of the wind energy installation and a permissible maximum value for the current.
7. The wind energy installation of claim 6 , wherein an output of the power observer is connected to a desired value input of the negative phase sequence system regulation mechanism.
8. The wind energy installation of claim 6 , further comprising a limiting module configured to limit at least one of an active and a reactive component of current in the negative phase sequence system depending on the power observer.
9. The wind energy installation of claim 6 , further comprising a threshold value switch which acts on the negative phase sequence system regulation mechanism in such a way that unbalances below a threshold are tolerated.
10. The wind energy installation of claim 9 , wherein the threshold value switch is integrated into the power observer.
11. The wind energy installation of claim 4 , further comprising a crossover module configured to combine regulation of the negative phase sequence system with that of a positive phase sequence system.
12. A wind farm comprising:
a plurality of wind energy installations, each wind energy installation comprising a generator which is driven by a rotor and generates electrical power in a polyphase manner for feeding into a grid, a converter connected to the generator and the grid, and a controller which interacts with the converter;
a wind farm regulation mechanism comprising a negative phase sequence system regulation mechanism having a phase control module configured to determine an electrical variable of a negative phase sequence system in a phase-specific manner; and
a priority module that directs the wind farm regulation mechanism to feed in as much active current as possible in a positive phase sequence system during normal operation and to selectively supply reactive current in the positive and negative phase sequence system if a fault situation in the grid is identified, depending on the balanced and unbalanced components of the voltage that occurs.
13. The wind farm of claim 12 , wherein the negative phase sequence system regulation mechanism comprises an active power regulator.
14. The wind farm of claim 12 or 13 , wherein the negative phase sequence system regulation mechanism is embodied in the wind farm with the inclusion of external reactive power controllers.
15. A method for regulating a wind energy installation, the wind energy installation comprising a generator which is driven by a rotor and generates electrical power in a polyphase manner for feeding into a grid, a converter connected to the generator and the grid, and a controller which interacts with the converter, comprising the following steps:
detecting current and voltage values for the phases of the grid;
transforming the detected current and voltage values into a positive phase sequence system and a negative phase sequence system;
providing phase-specific regulation in the negative phase sequence system; and
feeding in as much active current as possible in the positive phase sequence system during normal operation and selectively supplying reactive current in the positive and negative phase sequence system if a fault situation in the grid is identified, depending on the balanced and unbalanced components of the voltage that occurs.
16. The method of claim 15 , wherein a negative phase sequence system regulation mechanism comprising an active power regulator is used to provide phase- specific regulation in the negative phase sequence system.