Electronic Decoupling Apparatus for Power Plant Frequency Isolation
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Solution Overview
Problem
Large power stations with fixed coupling between turbine rotational speed and grid frequency face limitations in stable operation, output control, efficiency optimization, emissions control, and service life due to rigid frequency coupling, leading to transients and increased emissions during frequency fluctuations.
Innovation Solution
Implementing an electronic decoupling apparatus, such as a matrix converter, between the generator and electrical grid to decouple the operating frequency from the grid frequency, allowing constant turbine rotational speed and immediate output adjustments during longer-lasting grid frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed coupling between turbine rotational speed and grid frequency is used, then the generator output is connected at a locked frequency to the electrical grid, but the power station cannot respond flexibly to grid frequency fluctuations, leading to transients and increased emissions
Solution Approach 1:
An electronic decoupling apparatus (matrix converter) is introduced as an intermediary between the generator and the electrical grid. This device decouples the turbine rotational speed from the grid frequency, allowing the turbine to operate at constant speed while the converter handles frequency variations. The electronic gearbox acts as a mediator that transfers power while independently controlling speed and frequency, thereby resolving the contradiction between reliable operation and adaptive output control.
Solution Approach 2:
The patent replaces the traditional mechanical coupling (direct shaft connection) between turbine and generator with an electronic system. Instead of mechanically linking turbine speed to grid frequency through a fixed ratio, an electronic matrix converter is used to decouple these parameters. This substitution allows independent control of turbine rotational speed and generator output frequency, eliminating transients and enabling flexible response to grid conditions.
2Productivity
If the turbine rotational speed is adjusted during grid frequency changes, then the output can be controlled, but transients occur and emissions increase
Solution Approach 1:
The electronic decoupling apparatus serves as an intermediary that separates the turbine operation from grid frequency requirements. The matrix converter allows the turbine to maintain constant rotational speed (avoiding transients and emissions) while the electronic device adjusts the output frequency and power delivered to the grid. This mediator enables productivity adjustment without harmful effects.
3Device complexity
If a mechanical gearbox is used to achieve different rotational speed ratios, then higher rotational speeds and smaller constructions are possible, but stability issues arise for outputs greater than 130 MW
Solution Approach 1:
The patent replaces the mechanical gearbox system with an electronic matrix converter. Instead of using mechanical gears to achieve rotational speed transformation, the electronic device performs the same function through power electronic conversion. This substitution eliminates the stability issues associated with mechanical gearboxes at high power outputs while maintaining the ability to achieve different speed ratios and compact construction.
4Adaptability or versatility
If the turbine operates at variable speeds to support grid frequency, then frequency support is possible, but the service life of turbine components is reduced due to thermal and mechanical loading
Solution Approach 1:
The electronic decoupling apparatus acts as a mediator that absorbs the frequency variations and power adjustments, allowing the turbine to operate at constant speed. This protects the turbine components from thermal and mechanical loading that would occur during speed variations, thereby extending service life while maintaining grid frequency support capability through the electronic converter.
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
This solution enables stable grid frequency support, reduced emissions, improved service life, and flexibility in load fluctuations, allowing for efficient operation and optimized output independent of grid frequency, thereby preventing transients and extending component life.
Implementation Method 1
an electronic decoupling apparatus, such as a matrix converter, between the generator and electrical grid to decouple the operating frequency from the grid frequency
Data Source
AI summary
A method is provided for operating a power station (10), with turbine shafting (11), that includes a gas turbine (12) and a generator (18) driven directly by the gas turbine (12) and that generates alternating current with an operating frequency, the output of the generator is connected with an electrical grid (21) with given grid frequency. An electronic decoupling apparatus or variable electronic gearbox (27) is arranged between the generator (18) and the grid (21), the decoupling apparatus decouples the operating frequency from the grid frequency. Increased service life of the station and reduced emissions are achieved in that, when there are longer-lasting changes in the grid frequency, the mechanical or aerodynamic rotational speed of the gas turbine (12) is kept constant and the output of the gas turbine (12) is adjusted without a delay.