31.5
Transiente Stabilität und Systemkontrollen
Die Regelung der Generatorspannung ist für den stabilen Betrieb von Synchrongeneratoren und Windturbinen von entscheidender Bedeutung. Bei älteren Mod…
Bei Synchrongeneratoren liefert der Erreger Gleichstrom an die Feldwicklung des Rotors.
Ältere Modelle verwenden einen rotorgetriebenen Gleichstromgenerator als Erreger, während moderne Modelle statische oder bürstenlose Erreger verwenden.
Statische Erreger gleichen den Wechselstrom von den Generatorklemmen oder dem Bus und versorgen den Rotor.
Bürstenlose Erreger verwenden einen invertierten Synchrongenerator, der Wechselstrom von den Ankerwicklungen zur Feldwicklung gleichrichtet.
Erreger vom Typ 1 verfügen über einen wellengetriebenen Gleichstromgenerator und einen Spannungsregler, der den Feldstrom basierend auf der Anschlussspannung anpasst.
In Windkraftanlagen variiert die Spannungsregelung je nach Erregertyp. Typ 1 verfügt nicht über eine direkte Steuerung, während Typ 2 eine Widerstandsregelung verwendet, um die Leistungsabgabe bei Windböen konstant zu halten.
Erreger vom Typ 3 regeln die Blindleistung, indem sie sie konstant halten oder mit der realen Leistung variieren.
Blockdiagramme visualisieren die Regelung der Generatorspannung in transienten Stabilitätsprogrammen.
Schnell ansprechende Erreger mit hoher Verstärkung erhöhen die Feldspannung bei Kurzschlüssen und verbessern so die Transientenstabilität.
Blockdiagrammgleichungen berechnen das Einschwingverhalten.
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Q1: What is the difference between static and brushless exciters in synchronous generators?
Static exciters rectify AC power from generator terminals or bus and supply DC power directly to the rotor field winding. Brushless exciters use an inverted synchronous generator, rectifying AC power from armature windings via diodes mounted on the rotor, eliminating slip rings and brushes. Both replace older rotor-driven DC generators, improving reliability and reducing maintenance.
Q2: How does a Type 1 exciter control generator terminal voltage?
A Type 1 exciter uses a shaft-driven DC generator with a voltage regulator that measures terminal voltage and compares it to a reference voltage. The voltage error is processed with a gain and time constant, producing a field voltage that adjusts the rotor field current. This feedback mechanism maintains stable terminal voltage output.
Q3: Why do high-gain, fast-responding exciters improve transient stability?
High-gain, fast-responding exciters rapidly increase field voltage during short circuits, strengthening the generator's ability to maintain synchronism. This quick response enhances the simplified synchronous machine model's transient performance by providing immediate reactive power support. Faster exciter response reduces voltage dips and improves overall system stability during disturbances.
Q4: What voltage control methods are used in different wind turbine types?
Type 1 wind turbines use squirrel cage induction machines without direct voltage regulation. Type 2 systems employ wound rotor machines with adjustable external resistance to maintain constant power during wind gusts. Type 3 and Type 4 configurations manage both real and reactive power, providing enhanced control over generator output.
Q5: How do block diagrams represent generator voltage control systems?
Block diagrams visualize the feedback control loop by showing terminal voltage measurement compared against reference voltage, with the error processed through a voltage regulator with gain and time constant parameters. These diagrams compute transient response equations and standardize the representation of exciter and generator dynamics for stability analysis and system design.
Q6: What role does the field winding play in synchronous generator voltage control?
The field winding receives DC power from the exciter, creating the magnetic field that generates terminal voltage. The voltage regulator adjusts field current based on terminal voltage feedback, allowing precise control of generator output. This excitation control is essential for maintaining stable voltage and improving transient stability during system disturbances.
Q7: How does Type 2 wind turbine resistance control maintain power output stability?
Type 2 wind turbines use adjustable external resistance in the rotor circuit of wound rotor induction machines to regulate slip and power output. During wind speed variations, the resistance adjustment maintains consistent power delivery despite changing wind conditions. This resistance control mechanism provides a cost-effective alternative to direct voltage regulation in variable-speed wind turbine systems.