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The open-circuit saturation curve (also open-circuit characteristic, OCC) of a synchronous generator is a plot of the output open circuit voltage as a function of the excitation current or field. The curve is typically plotted alongside the synchronous impedance curve .
where temperature T is in degrees Celsius (°C) and saturation vapor pressure P is in kilopascals (kPa). According to Monteith and Unsworth, "Values of saturation vapour pressure from Tetens' formula are within 1 Pa of exact values up to 35 °C." Murray (1967) provides Tetens' equation for temperatures below 0 °C: [3]
The saturation with respect to water cannot be measured much below –50 °C, so manufacturers should use one of the following expressions for calculating saturation vapour pressure relative to water at the lowest temperatures – Wexler (1976, 1977), [1] [2] reported by Flatau et al. (1992)., [3] Hyland and Wexler (1983) or Sonntag (1994 ...
The Penman equation describes evaporation (E) from an open water surface, and was developed by Howard Penman in 1948. Penman's equation requires daily mean temperature, wind speed, air pressure, and solar radiation to predict E. Simpler Hydrometeorological equations continue to be used where obtaining such data is impractical, to give comparable results within specific contexts, e.g. humid vs ...
Hydrogen-cooled turbo generator's cooling can be improved by increasing the hydrogen pressure, larger generators, from 300 MVA, use more efficient water cooling. [3] Capability curve of a synchronous generator with minimum load. The practical D-curve of a typical synchronous generator has one more limitation, minimum load. The minimum real ...
In a synchronous generator, [1] the short circuit ratio is the ratio of field current required to produce rated armature voltage at the open circuit to the field current required to produce the rated armature current at short circuit. [1] [2] This ratio can also be expressed as an inverse of the saturated [3] direct-axis synchronous reactance ...
Fig. 1 L P σ and L S σ are primary and secondary leakage inductances expressed in terms of inductive coupling coefficient under open-circuited conditions.. The magnetic circuit's flux that does not interlink both windings is the leakage flux corresponding to primary leakage inductance L P σ and secondary leakage inductance L S σ.
Static level is the level of water in the well when no water is being removed from the well by pumping. [8] Water table is the upper level of the zone of saturation, an underground surface in which the soil or rock is permanently saturated with water. [9] Well yield is the volume of water per unit time that is produced by the well from pumping. [8]