Archivo para marzo 1st, 2019


A load flow analysis allows identification of real and reactive power flows, voltage profiles, power factor and any overloads in the network. Once the network parameters have been entered into the computer database the analysis allows the engineer to investigate the performance of the network under a variety of outage conditions. The effect of system losses and power factor correction, the need for any system reinforcement and confirmation of economic transmission can then follow.

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The figure in this post shows the simplest type of circuit in which the series capacitor is protected by a self-triggered spark gap. The spark gap is set to flashover at a given voltage, usually in the range of 2.0–3.5 per unit (where 1.0 per unit is equal to the crest voltage produced across the series capacitor at rated current). But, the spark gap may not fire for low-current faults. Therefore, the line protection scheme must also perform properly with the series capacitor still in operation. The bypass breaker is used by an operator to remove the capacitor bank from the service for maintenance and for reinserting the capacitor bank into the service following these intentional removals


Tornados occur in most subtropical and temperate landmasses around the world. Fortunately, most tornados do not carry overwhelming winds and therefore cause limited structural damage to engineered structures. On average, 800 to 1,000 tornados occur each year in the contiguous United States, and the activity zone extends well up into Canada. The total number of reported tornados in 1-degree squares of latitude and longitude for a 30-year period (1950 to 1980) is shown in figure.