System for monitoring the travel curve of a moving part of a circuit breaker, the system comprising: - a device for optically monitoring the travel path of a moving part of a circuit breaker , the device comprising: ∘ a light source , ∘ a light detection device , ∘ an optical element having a plurality of zones with different optical properties which are alternately arranged, wherein the optical element is adapted to be provided on a moving part of a circuit breaker to be monitored, and wherein the light source emits light to the optical element which is intensity-modulated by the optical element and received by the light detection device during operation of the circuit breaker , characterised by : - an accelerometer adapted for mounting it to the circuit breaker to be monitored, - a control unit for receiving signals from the light detection device and from the accelerometer , the control unit being configured to determine a travel curve of the moving part of the circuit breaker based on the detected modulated light and on the detected vibration signal, wherein the vibration signal is employed to identify a change of direction of movement of the moving part of the circuit breaker . - a device for optically monitoring the travel path of a moving part of a circuit breaker , the device comprising: ∘ a light source , ∘ a light detection device , ∘ an optical element having a plurality of zones with different optical properties which are alternately arranged, wherein the optical element is adapted to be provided on a moving part of a circuit breaker to be monitored, and wherein the light source emits light to the optical element which is intensity-modulated by the optical element and received by the light detection device during operation of the circuit breaker , characterised by : - an accelerometer adapted for mounting it to the circuit breaker to be monitored, - a control unit for receiving signals from the light detection device and from the accelerometer , the control unit being configured to determine a travel curve of the moving part of the circuit breaker based on the detected modulated light and on the detected vibration signal, wherein the vibration signal is employed to identify a change of direction of movement of the moving part of the circuit breaker . ∘ a light source , ∘ a light detection device , ∘ an optical element having a plurality of zones with different optical properties which are alternately arranged, wherein the optical element is adapted to be provided on a moving part of a circuit breaker to be monitored, and wherein the light source emits light to the optical element which is intensity-modulated by the optical element and received by the light detection device during operation of the circuit breaker , characterised by : - an accelerometer adapted for mounting it to the circuit breaker to be monitored, - a control unit for receiving signals from the light detection device and from the accelerometer , the control unit being configured to determine a travel curve of the moving part of the circuit breaker based on the detected modulated light and on the detected vibration signal, wherein the vibration signal is employed to identify a change of direction of movement of the moving part of the circuit breaker . - an accelerometer adapted for mounting it to the circuit breaker to be monitored, - a control unit for receiving signals from the light detection device and from the accelerometer , the control unit being configured to determine a travel curve of the moving part of the circuit breaker based on the detected modulated light and on the detected vibration signal, wherein the vibration signal is employed to identify a change of direction of movement of the moving part of the circuit breaker . <EOS>