Mechanical Pole Testing Using Partial Load Force for Application in Electric Utilities

摘要

The transmission and distribution networks of electric utilities normally consist of overhead lines and underground cables. For distribution overhead lines conductors are supported by poles which are usually made of wood, steel or reinforced concrete. The design life of these poles is in the range of 20 to 50 years. It is necessary to test and confirm that adequate levels of safety and reliability can be maintained throughout the remaining life when the facilities have been operated for more than 10 years. Safety to work on poles as well as public safety can be dramatically enhanced if all poles are periodically inspected and mechanically tested in order to prove that they are capable to withstand the worst operating conditions such as severe typhoon, hurricane, cyclone and the like. This paper describes an innovative and non-destructive approach, namely the 'Mechanical Pole Testing' (MPT) with partial load force, to evaluate the pole strength in a cost-effective manner. The Mechanical Pole Testing method applies a real pressure on a pole. By simulating a percentage of pressures applicable in real wind conditions, and taking some measurements, this method can accurately determine whether a particular pole has the minimum needed strength, what is its total strength, its degree of degradation (if any) and even its estimated remaining serviceable life. The testing process can be completed in a short interval of 15 minutes. With such quantifiable data on pole condition, electric utilities can make appropriate judgments on preventive and corrective maintenance measures to maintain the pole and hence sustain the stability of network supply at a minimal cost.