Converter-based generators and method for feeding in electrical power

Patent metadata

Field	Value
Publication number	US-11641115-B2
Application number	US-202117406923-A
Country	US
Kind code	B2
Filing date	Aug 19, 2021
Priority date	Aug 20, 2020
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

Provided is a method for feeding electrical power into an electrical supply network having a network voltage with a network frequency by means of a converter-based generator, in particular by means of a wind power system, comprising the following steps: estimating a converter proportion, representing a ratio of power fed in by means of converters to total power fed in, of a network section of the electrical supply network, feeding electrical power into the electrical supply network in a normal mode, and activating at least one support control for supporting the electrical supply network. The activating is effected depending on the converter proportion, the at least one support control is adjustable in each case by way of a degree of activation, and the degree of activation of the at least one support control is dependent in each case on the estimated converter proportion.

First claim

The invention claimed is:

1. A method for feeding electrical power into an electrical supply network having a network voltage with a network frequency using a converter-based generator, comprising:
estimating a converter proportion of a network section of the electrical supply network, wherein the converter proportion represents a ratio of power fed in using converters to a total fed in power;
feeding the electrical power into the electrical supply network in a normal mode; and
activating at least one support control for supporting the electrical supply network, wherein:
the activating is performed depending on the converter proportion,
the at least one support control is adjustable using a degree of activation,
the degree of activation of the at least one support control is dependent on the converter proportion,
the degree of activation has a value profile that is dependent on the converter proportion,
the degree of activation has values in a range of 0 to 100% continuously or in more than two steps,
a support control of the at least one support control is fully activated if the degree of activation associated with the support control is 100%, and
the support control of the at least one support control is deactivated if the degree of activation associated with the support control is 0%.

2. The method as claimed in claim 1 , wherein the converter-based generator is a wind power system.

3. The method as claimed in claim 1 , wherein:
the support control is characterized by a transfer function, and wherein the degree of activation is applied as factor to the transfer function or if the support control is implementable by a plurality of controllers, a number of the plurality of controllers used for the support control is dependent on the degree of activation, such that the degree of activation is positively correlated with the number of the plurality of controllers, and/or
a proportion range for the converter proportion is classified in a lower, middle and upper proportion range, wherein
the lower proportion range is below a first reference value,
the middle proportion range is from the first reference value to a second reference value greater than the first reference value, and
the upper proportion range is above the second reference value.

4. The method as claimed in claim 3 , wherein in particular the first reference value is in a range of 50-60%, and/or the second reference value is in a range of 80-95%.

5. The method as claimed in claim 3 , wherein the first reference value and/or the second reference value are/is selected depending on a network property of the electrical supply network.

6. The method as claimed in claim 5 , wherein the first reference value and/or the second reference value are/is selected depending on a load flow measure representing a maximum power flow between the network section and a remaining part of the electrical supply network.

7. The method as claimed in claim 3 , wherein
in response to a maximum degree of activation being in the middle proportion range, an emulation function is activated, the emulation function reacting to a frequency change in the network frequency with a power change of the electrical power, wherein the power change as a reaction to the frequency change emulates a behavior of a synchronous machine coupled directly to the electrical supply network.

8. The method as claimed in claim 7 , wherein a virtual centrifugal mass with adjustable mass moment of inertia is used for the synchronous machine, and wherein:
the degree of activation for adjusting the emulation function increases in the lower proportion range from a first value of a maximum of 10% as the converter proportion increases, reaches a maximum value in the middle proportion range, decreases again as the converter proportion increases further, and reaches a second value of a maximum of 10% in the upper proportion range, and/or
the emulation function is adjusted by multiplication by the degree of activation, and/or
the power change of the electrical power as the reaction to the frequency change has an amplitude that is at least double a magnitude of a power change of the electrical power of a frequency-dependent power control operating in parallel without emulation of the synchronous machine for the same frequency change, and/or
for the power change of the electrical power as the reaction to the frequency change, no minimum frequency deviation of the network frequency from a reference frequency is predefined, or wherein a predetermined minimum frequency deviation is at least smaller than in a case of the frequency-dependent power control operating in parallel without emulation of the synchronous machine.

9. The method as claimed in claim 3 , wherein
in response to a maximum degree of activation in the middle proportion range,
a power limitation function for rapid power limitation is implemented, wherein the power limitation function reduces the electrical power in response to a request signal or request criterion, and
the reduction of the electrical power is characterized by a reduction time constant, wherein the reduction time constant represents a time in which the electrical power is reduced by a rated power value, wherein the reduction time constant is less than 2 seconds.

10. The method as claimed in claim 9 , wherein:
the degree of activation for adjusting the power limitation function increases in the lower proportion range from a first value of a maximum of 10% as the converter proportion increases, reaches a maximum value in the middle proportion range, decreases again as the converter proportion further increases, and reaches a second value of a maximum of 10% in the upper proportion range, and/or
the power limitation function is multiplied by the degree of activation for adjusting the power limitation function, and/or
with the use of a wind power system as the converter-based generator, the reduction of the electrical power is more rapid than a reduction of power generated from wind using the wind power system, and/or
power is additionally consumed in the wind power system using a chopper circuit for reducing the electrical power, and/or
the electrical power is reduced to a value below zero such that the wind power system draws power from the electrical supply network.

11. The method as claimed in claim 3 , wherein in response to a maximum degree of activation in the middle proportion range, a frequency gradient control is activated, wherein the frequency gradient control alters the electrical power depending on a frequency gradient that quantitatively represent a frequency change per time.

12. The method as claimed in claim 11 , wherein:
the frequency gradient represents a portion of the electrical power proportionally to the frequency change, and
the degree of activation for adjusting the frequency gradient control increases in the lower proportion range from a first value of a maximum of 10% as the converter proportion increases, reaches a maximum value in the middle proportion range, decreases again as the converter proportion further increases, and reaches a second value of a maximum of 10% in the upper proportion range, and/or
the frequency gradient control is multiplied by the degree of activation for adjusting the frequency gradient control.

13. The method as claimed in claim 3 , wherein:
in response to a maximum degree of activation in the upper proportion range a frequency-dependent power control is activated, in which the electrical power is altered depending on the network frequency in accordance with a control specification, and the control specification has a control gain and/or is charac

Assignees

• Wobben Properties Gmbh

Inventors

• Brombach Johannes

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02J3/381 Primary

  Dispersed generators · CPC title

• H02J3/466

  Scheduling or selectively controlling the operation of the generators or sources, e.g. connecting or disconnecting generators to meet a demand · CPC title

• Y02E10/76

  Power conversion electric or electronic aspects · CPC title

• H02J3/46

  Controlling the sharing of generated power between the generators, sources or networks · CPC title