Generator Set Engine Speed Reference Control for Transient Load Stability

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Solution Overview

Problem

Existing methods for load sharing between generator sets in power networks, particularly during transient load situations, do not adequately account for individual engine capabilities, leading to potential undesired states like knocking or misfire.

Innovation Solution

A method and control unit that determine a speed reference value by combining actual engine load with a load reference value, incorporating transient state analysis and engine characteristics to optimize load distribution, using a feed-forward control mechanism and differentiated engine characteristics for dual-fuel engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If isochronous load sharing control is used to maintain constant speed and high power quality, then frequency and voltage stability is improved, but during transient load situations individual engine capabilities are not adequately accounted for leading to engine instability like knocking or misfire

Engineering Contradiction:
Improvefrequency and voltage stabilityVSAvoidengine stability during transient load
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The control method performs preliminary identification of transient load situations and proactively adjusts the speed reference value before the engine enters an unstable state. By detecting transient conditions early and adjusting fuel injection accordingly, the system prevents knocking or misfire while maintaining isochronous load sharing operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces dynamic adjustment of the speed reference value based on transient load conditions. Instead of maintaining a fixed speed reference, the system dynamically modifies it during transient situations to account for individual engine capabilities, thereby preventing engine instability while preserving frequency and voltage stability.

Inventive Principle:
Principle #15Dynamics

2Productivity

If traditional load sharing control increases speed reference when engine load is less than load reference, then load sharing is achieved, but individual engine characteristics and capabilities are not considered leading to suboptimal load distribution

Engineering Contradiction:
Improveload sharing capabilityVSAvoidadaptation to individual engine characteristics
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The control method applies local quality by tailoring the speed reference adjustment to each individual engine's characteristics and capabilities. Instead of using a uniform control strategy for all engines, the system considers specific engine properties when determining the speed reference value, enabling optimized load distribution that respects individual engine limitations and strengths.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the speed reference value parameter dynamically based on both load conditions and individual engine characteristics. By modifying this key control parameter according to transient situations and engine-specific properties, the system achieves both effective load sharing and adaptation to individual engine capabilities.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3363114B1Method of controlling operation of an engine of a generator set, and a control unit for an engine of a generator set
Publication Date: 2020.06.03 WARTSILA FINLAND OY
  • EP3363114B1 patent drawingFigure 1
  • EP3363114B1 patent drawingFigure 2
  • EP3363114B1 patent drawingFigure 3

AI summary

Invention relates to method of controlling operation of an engine of a generator set in an assembly of at least two generator sets coupled parallel to an electric grid, wherein method, - actual engine speed is determined or measured, and fuel feeding into the engine is controlled making use of the actual engine speed and a speed reference value, wherein - actual engine load is determined or measured, - a load reference value is determined based on the actual engine loads of the engines coupled to the electric grid, and - the speed reference value is determined such that the speed reference value is a sum of: - a first part of the speed reference value obtained by making use of the actual engine load and the load reference value, and - a second part of the speed reference value obtained by - identifying transient state from the load reference value and - combining the transient state with engine characteristics to provide the second part of the speed reference value.