17%* of all transformer failures can be traced back to bushing defects, and are also the main cause for transformer fires. At the same time, the Network requirements for availability and reliability of transformers is increasing. Continuous condition monitoring and evaluation of the bushings is therefore imperative. MSENSE® BM enables early detection of bushing errors and therefore allows action to be taken before the transformer is damaged.
*Quelle: Cigre A2.37
Continuous status monitoring is possible with the MSENSE® BM online monitoring system. MSENSE® BM monitors the relevant variables directly at the RIP (resin impregnated paper), OIP (oil impregnated paper) or RIS (resin impregnated synthetic) bushings of the voltage levels from 10 kV to 800 kV.Um = 765 kV*.
An innovative and field-tested algorithm monitors the condition of the inner conductive layers of the bushing field grading in regard to changes in capacitance (C) and dissipation factor (tan δ) and compares these changes to limit values. The key aspect of this innovation is the 2/3 reference method: the algorithm continuously incorporates all three bushings into mutual monitoring. In addition, just only the measurement data of potential transformers on the system are required to determine the symmetry of the grid voltage. This ensures a reliable and clear evaluation of the condition of the high-voltage bushings – regardless of network asymmetries or fluctuations in voltage.