Ice galloping occurs for transmission and distribution lines in many areas of the world. It occurs as the combined result of ice on the conductors and strong winds. While the resulting conductor questions are of relatively orotund amplitude, the main result of such motions is electrical not mechanistic failure. Once ice forms on the conductor it usually adheres for the continuation of the galloping motions until the wind eventually stops or the air temperature rises. assorted techniques have been suggested including the use of drag devices, reduction in sag, and inter-phase spacing insulators. Davison of Ontario Hydro suggested the first effective means of control in 1939 [10]. He described the concept of providing sufficient phase-to-phase spacing when new lines are designed so that flashovers during galloping are prevented. Calculation of minimum mandatory phase-to-phase spacing is done in terms of galloping ellipses based on observation of ice galloping occurrences.
Figure 1 - Ice Galloping ellipse for Phase Spacing Calculations [3]
Other methods were developed in subsequent years. A second effective means of galloping control resulted from the studies of galloping at MIT under Richardson in the early 1960s.
This device, called the wind damper or drag damper, has been refined over the intervening years. A tercet effective means of control â€" the detuning pendulum â€" was developed at Ontario Hydro in the 1970s and became the object of an extensive field investigation by EPRI in the early 1980s. The effectiveness of this device is supported by a thorough statistical analysis of the field data. A fourth
method of galloping control by means of either spoilers or VR conductor has also become available in juvenile years. Ice galloping motions occur at one of the fundamental unsloped string modes of the catenary â€" usually the first, second, or third mode. The amplitude of motion associated with the single loop mode is of primary concern, because the...If you want to amount a full essay, order it on our website: Orderessay
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