In order to effectively detect the operation condition of high voltage circuit breaker based on spring mechanism

the typical current waveform of opening/closing coil is analyzed based on a characteristic extraction method of spline interpolation and multi-scale linear fitting.The method set the time and amplitude matched with the extreme point as the characteristic.The current waveform is firstly smoothed by the cubic splice interpolation

smoothed by the cubic splice interpolation.The signal is divided into several sections by a large scale.Each section is fitted by least square method

and the extreme points can be limited into typical intervals according to the trends of each section.Then the scale is reduced and the procedure would be repeated until the interval is small enough to determine the extreme points as the characteristic points.Finally

the method is applied to detect the mechanical condition of the real circuit breaker in a typical substation.The results have shown that the proposed method can extract the characteristics of opening/closing coil current rapidly and correctly

which can effectively detect the condition of circuit breaker.