Method of detecting a rotor bar fault and a method of estimating an additional operating expenditure due to one or more mechanical anomalies in an electrical machine

A non-transitory computer readable storage medium having stored thereon instructions for instructing a processing unit of a system to execute a method of detecting a broken or cracked rotor bar during online operation of an electrical machine, said method comprising,

• acquiring a set of online signals from the electrical machine over a period, said set of online signals comprising at least one vibration signal, a summed signal of magnetic flux signals, each magnetic flux signal obtained from a respective flux sensor positioned on an external surface of the electrical machine,
• wherein the summed signal of magnetic flux signals is obtained by acquiring and summing a set of p flux signals to obtain a total flux signal, wherein the set of p flux signals is acquired from p flux sensors positioned along a circumference of a cylindrical frame of the electrical machine, such that any two adjacent flux sensors along the circumference of the cylindrical frame have an angular separation of 360/p degrees with respect to the longitudinal axis of the cylindrical frame, wherein p represents the total number of poles of the electrical machine;
• extracting an online anomaly indicator value from the set of online signals;
• comparing the online anomaly indicator value with a baseline anomaly indicator value of a corresponding loading condition;
• and
• determining presence of a broken or cracked rotor when the online anomaly indicator value deviates from the baseline anomaly indicator value by a threshold.

A method of estimating an additional operating expenditure due to one or more mechanical anomalies in an electrical machine, the method comprising,

• acquiring a set of online signals from the electrical machine over a period, said set of signals comprising at least one vibration signal, at least one magnetic flux signal and at least one current signal;
• extracting an online anomaly indicator value from the set of online signals;
• comparing the online anomaly indicator value with a baseline anomaly indicator value of a corresponding loading condition;
• determining presence of mechanical anomaly when the online anomaly indicator value deviates from the baseline anomaly indicator value by a threshold;
• and
• computing the additional operating expenditure over a time frame, said time frame starting from an instance when the mechanical anomaly is determined until an instance when an overall vibration velocity of the electrical machine is projected to reach a defined unacceptable range.

A non-transitory computer readable storage medium having stored thereon instructions for instructing a processing unit of a system to execute a method of estimating an additional operating expenditure due to one or more mechanical anomalies in an electrical machine, said method comprising,

• acquiring a set of online signals from the electrical machine over a period, said set of signals comprising at least one vibration signal, at least one magnetic flux signal and at least one current signal;
• extracting an online anomaly indicator value from the set of online signals;
• comparing the online anomaly indicator value with a baseline anomaly indicator value of a corresponding loading condition;
• determining presence of mechanical anomaly when the online anomaly indicator value deviates from the baseline anomaly indicator value by a threshold;
• and
• computing the additional operating expenditure over a time frame, said time frame starting from an instance when the mechanical anomaly is detected until an instance when an overall vibration velocity of the electrical machine reaches a defined unacceptable range.