Source Side Converter Frequency Damping for Grid Stability

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Solution Overview

Problem

The variability in power generation from intermittent renewable sources like wind, tidal, and solar farms introduces unwanted power changes, leading to grid instability and economic implications due to differences in frequency characteristics between these sources and existing power transmission networks.

Innovation Solution

A power transmission network with a control system that operates source side converters in a frequency damping mode to dampen undesirable frequency components at the AC connecting point and within the AC transmission link, ensuring stable power transmission by accommodating variations in power generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variable power sources (wind, tidal, solar farms) are connected to the power grid, then the utilization of renewable energy resources is improved, but grid instability occurs due to frequency characteristic differences between these sources and the transmission network

Engineering Contradiction:
Improveutilization of renewable energy resourcesVSAvoidgrid stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A frequency damping controller is introduced as an intermediary device between the variable power source and the power transmission network. This controller specifically targets and dampens frequency oscillations, acting as a mediator that allows renewable energy integration while maintaining grid stability by filtering out destabilizing frequency variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts control parameters of the frequency damping controller based on detected frequency oscillations. By changing control parameters in response to varying operating conditions, the system maintains effective frequency damping across different scenarios, resolving the contradiction between accommodating variable power sources and maintaining stable grid operation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If frequency damping control is applied to source side converters, then grid stability is improved, but control system complexity increases

Engineering Contradiction:
Improvegrid stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The frequency damping controller is designed to work with existing source side converters, making them multi-functional. The same converter infrastructure serves both its original power conversion function and the additional frequency damping function, thereby improving grid stability without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control system employs feedback mechanisms that monitor frequency oscillations and automatically adjust control actions. This closed-loop approach achieves effective frequency damping through relatively simple control logic that responds to actual system conditions, avoiding the need for complex open-loop control schemes.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3070805B1Power transmission network
Publication Date: 2021.04.28 GENERAL ELECTRIC TECH GMBH
  • EP3070805B1 patent drawingFigure 1~2a
  • EP3070805B1 patent drawingFigure 2b
  • EP3070805B1 patent drawingFigure 2c

AI summary

A power transmission network comprises: a variable power source; an AC transmission link for AC power transmission from the variable power source to at least one source side converter; at least one source side converter including: an AC connecting point operably connected to the AC transmission link; and a DC connecting point for connection to a DC transmission link; and a control system configured to operate the source side converter or at least one of the source side converters in a frequency damping mode to control an AC voltage at its AC connecting point and thereby damp at least one frequency component at its AC connecting point and/or in the AC transmission link.