Probability of defects detection by NDT complex can be defined through the probability of defects detection parameters of separate NDT methods, which are included in technology s l . To increase the reliability of control for cables technical condition it is expedient to use a principle of redundancy of the control, i.e. to control the same defect by applying a complex of NDT methods, based on different physical nature. The using of multitude of various methods and ways of their application can contribute to increasing the probability of defect detection. To using of NDT complex, as well as examination procedure are directed at formation of the valid conditions, increasing of reliable operation and decreasing of risk. Let's consider formal optimization tasks.
All defects have to be detected.
Given condition could be interpreted as follows. Some unimportant defects are considered not to be detected. Defects in set D could have various importance and therefore it is possible to speak about inadmissibility, possibility of detection or not detection of dangerous and other defects, and these defects cannot result in considerable consequences. By other worlds the probable cost of element fault is insignificant for availability of power system as a whole. In a common case for such tasks, the fault of separate elements could not always result in occurrence of an emergency or fault of system as a whole.