Synchronous Machine Grid Stabilization for Reactive Power Support

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Solution Overview

Problem

The increasing integration of renewable energy sources like wind turbines and photovoltaic systems into energy supply networks poses challenges for voltage stability and frequency stabilization due to lack of reactive power provision and small rotating masses.

Innovation Solution

An arrangement comprising a rotating synchronous machine and a converter with an energy storage device, controlled by multiple units to automatically adjust speed and feed reactive power into the network during faults, ensuring controlled stabilization measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If renewable energy sources (wind turbines, photovoltaic systems) are integrated into energy supply networks, then energy production capacity is improved, but voltage stability and frequency stabilization deteriorate due to lack of reactive power provision and small rotating masses

Engineering Contradiction:
Improveenergy production capacityVSAvoidvoltage stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A synchronous machine is introduced as an intermediary device between the renewable energy sources and the energy supply network. This synchronous machine provides the missing reactive power and rotating mass, mediating the connection between modern renewable energy systems and the traditional grid requirements for stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The synchronous machine performs multiple functions simultaneously: it provides reactive power for voltage stability, contributes rotating mass for frequency stabilization, and can operate in different modes (synchronous condenser mode for reactive power, generator mode for active power). This multi-functionality addresses multiple stability issues with a single device.

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

2Productivity

If renewable energy sources are integrated into energy supply networks, then energy production capacity is improved, but frequency stabilization deteriorates due to small rotating masses

Engineering Contradiction:
Improveenergy production capacityVSAvoidfrequency stabilization
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The synchronous machine serves as a mediator that contributes its rotating mass to the grid, providing the inertial support necessary for frequency stabilization that is otherwise missing from power electronic-based renewable energy systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The synchronous machine can dynamically adjust its operating parameters, including its rotational speed and reactive power output, to respond to frequency deviations and maintain frequency stability within acceptable ranges.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a synchronous machine operates in phase shifter mode without additional control, then device complexity is reduced, but voltage stability control capability deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidvoltage stability control capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The synchronous machine's excitation system is made dynamic and controllable. The excitation voltage can be adjusted in real-time based on grid conditions, allowing the machine to provide controlled reactive power output for voltage stabilization rather than operating passively in pure phase shifter mode.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A control unit continuously monitors the energy supply network's voltage and frequency conditions and provides feedback signals to adjust the synchronous machine's excitation voltage and operational mode, enabling automatic stabilization responses to grid disturbances.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables effective stabilization of electrical energy supply networks by providing controlled reactive power feed, addressing voltage stability and frequency deviations, and enhancing network resilience.

Implementation Method 1

only small rotating masses for frequency stabilization

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 2

The first control unit (11) applies an excitation voltage to the first device (10) and thereby causes the reactive power to be fed in by the first device (10)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the arrangement comprises a second control unit and a second device which has a converter and an energy storage device and is controlled by the second control unit, wherein in the event of a detected network fault of the first type, the second control unit controls the converter in such a way that it Reactive power, in particular the maximum possible reactive power, is fed from the converter into the energy supply network

Methodology Applied
Scientific EffectPower conversion:

Data Source

PatentEP3782255B1Arrangement and method for stabilizing an electrical energy supply network
Publication Date: 2023.09.20 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3782255B1 patent drawingFigure 1
  • EP3782255B1 patent drawingFigure 2
  • EP3782255B1 patent drawingFigure 3

AI summary

Arrangement and method for stabilizing an electrical energy supply network. The invention relates, inter alia, to an arrangement (1) for stabilizing an electrical energy supply network (2). The invention provides for the arrangement (1) to comprise a first device (10) which has a rotating mass and concomitantly rotates in sync with a desired network frequency of the energy supply network (2) during normal operation of the energy supply network (2), automatically feeds a current into the energy supply network (2) in the event of a short circuit in the energy supply network (2), and automatically adjusts its speed in the event of a frequency deviation of the network frequency of the energy supply network (2) from the desired network frequency, and for the arrangement (1) to have a first control unit (11, 11i) which is connected to the first device (10), controls the first device (10) if a network fault of a predefined first type is determined and thereby causes reactive power to be fed into the energy supply network (2) by the first device (10).