Static Exciter System for Generator Transient Stability
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Solution Overview
Problem
Existing generator control systems, particularly static exciter systems, face challenges in maintaining transient stability during grid faults, as they can exacerbate speed deviations between connected generators, leading to instability in the grid system.
Innovation Solution
A static exciter system that dynamically adjusts the field voltage of generator rotors by connecting a dynamic excitation system to each generator, using ultracapacitors to compensate for voltage drops and maintain stability by increasing the field voltage of accelerating generators while not increasing the field voltage of decelerating generators, thereby reducing speed deviations and enhancing transient stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excitation booster systems are applied to increase field voltage during grid faults, then the transient stability of individual generators is improved, but the speed deviations between connected generators increase, deteriorating the overall grid system stability
Solution Approach 1:
The control device receives signals from phasor measurement units that monitor rotor speeds of multiple generators, calculates the center of inertia speed as a reference, and provides feedback control signals to each static exciter system. This feedback mechanism enables coordinated control of field voltages across all generators, ensuring that excitation adjustments reduce rather than increase speed deviations, thereby maintaining overall grid stability while improving individual generator transient stability.
Solution Approach 2:
The system dynamically adjusts the field voltage parameter of each generator based on its rotor speed deviation from the center of inertia. By changing the field voltage parameter in response to real-time speed measurements, the system optimizes the electromagnetic torque to reduce speed deviations, resolving the contradiction between individual generator stability and overall grid stability.
2Power
If the field voltage is increased to compensate for voltage drops during grid faults, then the generator output is maintained, but the rotor speed deviations increase, leading to braking effects that impair grid stability
Solution Approach 1:
The system dynamically adjusts the field voltage parameter of each generator based on its rotor speed deviation from the center of inertia. By changing the field voltage parameter in response to real-time speed measurements, the system optimizes the electromagnetic torque to reduce speed deviations, resolving the contradiction between individual generator stability and overall grid stability.
Solution Approach 2:
The control device receives signals from phasor measurement units that monitor rotor speeds of multiple generators, calculates the center of inertia speed as a reference, and provides feedback control signals to each static exciter system. This feedback mechanism enables coordinated control of field voltages across all generators, ensuring that excitation adjustments reduce rather than increase speed deviations, thereby maintaining overall grid stability while improving individual generator transient stability.
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
The system effectively reduces speed deviations among connected generators, improving the overall transient stability of the grid by using a comparative value like the center of inertia to manage rotor speed, ensuring generators remain synchronized and grid stability is maintained during faults.
Implementation Method 1
a dynamic excitation system (28) connected to each generator (16), wherein the static exciter system (20) together with the field winding (17) form an exciter circuit for emission of electrical energy in case of a grid system fault
Data Source
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AI summary
The present invention relates to the field of generator technology. It is an object of the invention to control the stability of an electric grid in which a plurality of generators (16) are connected, providing electric power to the grid. Disclosed is a static exciter system comprising a control device (1) for controlling the field voltage of the field winding (7) of at least two generators connected to a grid system via a busbar.