Wind turbine gearbox order tracking analysis without keyphasor

Order tracking analysis has been demonstrated to be suitable for wind turbine gearbox fault diagnosis, but in traditional way, a keyphasor signal is indispensable. In some real cases, due to harsh working environment and installation space limitation, it´s hard to acquire this keyphasor signal. To overcome this problem, raw speed profile is used in this paper to synthesize the keyphasor, by assuming that the first pulse signal is at time zero, once the arriving time of the ith pulse is known, calculate the next pulse arrival time in two different ways, then minimizing the difference of these two results to get the next pulse arrival time. By assuming the shaft angular acceleration is constant between three consecutive pulses and using the synthesized keyphasor above, this paper successfully fulfill order tracking analysis on a United Stated MW-class wind turbine gearbox without keyphasor signal, which shows a very good engineering practicability.