LINE IMPEDANCE COMPENSATION SYSTEM

• US 20150263521A1
• Filed: 10/03/2013
• Published: 09/17/2015
• Est. Priority Date: 10/08/2012
• Status: Active Grant

• Current Assignee: Vestas Wind Systems A/S
• Original Assignee: Vestas Wind Systems A/S
• Inventors: Garcia, Jorge Martinez
• Granted Patent: US 9,859,710 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F03D 7/048 controlling wind farms
• CPC Class Codes: F03D 9/255 connected to electrical distribution networks; Arrangements therefor
• CPC Class Codes: H02J 2300/28 The renewable source being wind energy
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/18 Arrangements for adjusting, eliminating or compensating reactive power in networks for adjustment of voltage H02J3/16
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 10/76 Power conversion electric or electronic aspects
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

The present invention relates to a power plant controller (23), controlling at least one electrical parameter of a wind power plant at a first point (201), the power plant controller receiving at least one measured electrical parameter at a point of measurement (204a, b), the point of measurement being different from the first point, and estimating a delta value of a difference of the at least one electrical parameter between the first point and the point of measurement, wherein estimating of the delta value is calculated based on an impedance between the point of measurement and the first point, and at least one reference value of the power plant controller, and the power plant controller controls the at least one electrical parameter on the basis of the at least one measured electrical parameter and the delta value.

Claims

1. A power plant controller, arranged for controlling at least one electrical parameter of a wind power plant at a first point in an electrical grid wherein the wind power plant comprises a plurality of wind turbine generators, the power plant controller comprising:

an input device arranged for receiving at least one measured electrical parameter at a point of measurement, the point of measurement being different from the first point,

an algorithm for estimating a delta value of a difference of the at least one electrical parameter between the first point and the point of measurement, wherein estimating of the delta value is calculated based on an impedance between the point of measurement and the first point, and at least one electrical input parameter, and wherein the at least one electrical input parameter is at least one reference value of the power plant controller, and the power plant controller being arranged to control the at least one electrical parameter on the basis of the at least one measured electrical parameter and the delta value.

2. The power plant controller according to claim 1, wherein the value of the at least one electrical parameter at the first point is a summation of the at least one measured electrical parameter at the point of measurement and the estimated delta value.

3. The power plant controller according to claim 1, wherein the plurality of wind turbine generators is connected to an internal grid, and wherein the wind power plant is connected to an external grid through a point of common coupling, and the first point is the point of common coupling, and the point of measurement is at the internal grid or at the external grid.

4. The power plant controller according to claim 1, wherein the electrical parameter is a voltage level, and wherein the at least one electrical input parameter is at least a voltage reference value and a current reference value.

5. The power plant controller according to claim 4, wherein the delta value of the voltage level is estimated according to the following equation:

6. The power plant controller according to claim 1, wherein the electrical parameter is reactive power, and wherein the at least one electrical input parameter is at least a voltage reference value and a current reference value.

7. The power plant controller according to claim 6, wherein the delta value of the reactive power is estimated according to the following equation:

Δ

Q_s=(−

V_ref²Y+XI_ref²)·

l

8. The power plant controller according to claim 1, wherein the at least one electrical parameter is a voltage, and wherein the delta value is derived as a subtraction between the voltage at the first point and the voltage at the point of measurement, multiplied with a predetermined slope function, wherein the predetermined slope function is a function of the impedance between the point of measurement and the first point, and a further multiplication with the voltage at the point of measurement, for hereby estimating a reactive power reference.

9. The power plant controller according to claim 8, wherein the reactive power reference is compensated according to the impedance between the point of measurement and the first point, by adding a compensation value.

10. The power plant controller according to claim 1, wherein the power plant controller calculates a reference set point for the plurality of wind turbine generators, and the power plant controller further comprises a dispatcher to dispatch electrical reference set points to each one of the plurality of wind turbine generators.

11. The power plant controller according to claim 1, wherein the power plant controller further comprises at least one measuring device to measure the at least one measured electrical parameter at the point of measurement.

12. The power plant controller according to claim 1 wherein the power plant controller acts as a master controller for at least one local power plant controller, the at least one power plant controller controls a subset of the plurality of wind turbine generators.

13. Wind power plant arranged to be controlled by a power plant controller according to claim 1.

14. A method for controlling at least one electrical parameter of a wind power plant at a first point in an electrical grid, wherein the wind power plant comprises a plurality of wind turbine generators, the method comprising:

receiving at least one measured electrical parameter at a point of measurement, the point of measurement being different from the first point,

estimating a delta value of a difference of the at least one electrical parameter between the first point and the point of measurement, wherein estimating of the delta value is calculated based on an impedance between the point of measurement and the first point, and at least one electrical input parameter, wherein the electrical input parameter is a reference value of the power plant controller,

controlling the at least one electrical parameter on the basis of the at least one measured electrical parameter and the delta value.