Generator Feed-in Control for Grid Stability in Weak Networks

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Solution Overview

Problem

Decentralized generation units like wind turbines can cause loss of stability in electrical supply networks due to their fluctuating energy source and different operational characteristics compared to traditional power plants, and existing solutions do not adequately address this issue.

Innovation Solution

A method for controlling electrical energy generators connected to the grid, where network properties are recorded and used to adjust the feed-in of electrical current proactively, using a non-linear controller to set operating points that prevent loss of stability, allowing wind turbines and other decentralized generators to operate effectively even in weak networks with low short-circuit current ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If decentralized generation units like wind turbines are connected to the electrical supply network, then the quantity of electrical energy fed into the network increases, but the stability of the network deteriorates due to loss of stability phenomena

Engineering Contradiction:
Improveelectrical energy feed-inVSAvoidnetwork stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by proactively adjusting the feed-in of electrical current before instability occurs. The control device records network properties and uses this information to proactively modify generator operation, preventing loss of stability rather than reacting after it occurs. This is evident in the method where network properties are recorded and used to adjust feed-in proactively.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously recording network properties and using this information to control the feed-in of electrical current. The control device monitors network conditions and adjusts generator output based on recorded network properties, creating a closed-loop system that adapts to changing network conditions and maintains stability.

Inventive Principle:
Principle #23Feedback

2Stability of the object's composition

If power plants are designed with high short-circuit current ratio (above 10 or 15) to ensure grid stability, then the network stability improves, but the adaptability to weak networks deteriorates

Engineering Contradiction:
Improvegrid stabilityVSAvoidnetwork compatibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the feed-in of electrical current based on recorded network properties. Instead of requiring fixed design parameters like high short-circuit current ratios, the system modifies operational parameters (current feed-in levels) in real-time according to network conditions, enabling operation in both strong and weak networks.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by transitioning from static design requirements to dynamic operational adjustment. The control device continuously adapts the feed-in characteristics based on recorded network properties, allowing the system to respond dynamically to changing network conditions rather than relying on fixed design margins.

Inventive Principle:
Principle #15Dynamics

3Reliability

If synchronous generators are used for feeding electrical energy into the network, then the reliability of power generation is maintained, but the speed of response to network changes deteriorates due to slow adjustment processes

Engineering Contradiction:
Improvepower generation reliabilityVSAvoidresponse speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies mechanics substitution by replacing the mechanical inertia-based response of synchronous generators with electronic control of decentralized generation units. The control device uses electronic recording and processing of network properties to rapidly adjust feed-in, substituting the slow mechanical adjustment processes of traditional synchronous generators with fast electronic control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements dynamics by enabling rapid adjustment of feed-in characteristics through electronic control systems. The control device can quickly respond to recorded network property changes, providing fast adjustment capability that overcomes the inherent slowness of mechanical synchronous generator response while maintaining reliable power generation.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3595121A1Method and apparatus for feeding electric energy into an electric supply network
Publication Date: 2020.01.15 WOBBEN PROPERTIES GMBH
  • EP3595121A1 patent drawingFigure 1
  • EP3595121A1 patent drawingFigure 2
  • EP3595121A1 patent drawingFigure 3~5

AI summary

The invention relates to a method for controlling a generator (1) of electrical energy connected to an electrical supply network (4) at a network connection point (2), comprising the steps of recording at least one network property of the electrical supply network (4) relating to the network connection point (2), and controlling the generator (1) so that it feeds electricity into the electrical supply network (4) depending on the recorded network property.