Abstract
This paper studies a real 36-MW large tubular hydro-generator to solve the transient variation problem of the loss and heat of damper bars during short circuit faults in tubular hydro-generators. The transient analysis method of electromagnetic-temperature fields is adopted to study the transient variation problem of the loss and heat of damper bars during three-phase symmetrical short-circuits, single-phase to ground asymmetrical short-circuits, and phase-to-phase asymmetrical short-circuits under rated operation states. The research work provides valuable findings for improving the level of state analysis, the design and manufacturing processes, and the operation and maintenance of large-scale tubular hydro-generators.
Highlights
Damper windings are the key components for ensuring the safe and stable operation of hydro-generators, their state has a vital impact on the operational safety of generators
They are used as the initial heat source to solve the transient temperature field of the damper bar under the short-circuit fault condition
The loss of the third and fourth damper bars close to the windward side significantly increased, where the loss of the fourth damper bar, which is closest to the windward side, reached or even exceeded that of the first damper bar
Summary
Damper windings are the key components for ensuring the safe and stable operation of hydro-generators, their state has a vital impact on the operational safety of generators. During dangerous and special conditions, such as short circuits, negative sequences, etc., the loss and heat state of damper windings greatly affect their safe and stable operation, the generator, and the whole power grid. In comparison with hydro-generators in medium and high water heads, which are operated using. Impulse-type, mixed-flow-type, and axial-low-type turbines, tubular hydro-generators are best for developing and utilizing low water head rivers and tidal water energy resources, saving 20-30% of civil construction costs and increasing power generation by 3-5% [1], [2]. In case of a short-circuit fault, the damper windings are likely to face a severe loss and a heat impact, and their safety status becomes worse.
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