According to CIGRÉ, defective bushings are responsible for 17% of all transformer failures and about 50% of all transformer fires. Online monitoring by MSENSE BM & ETOS protects against transformer failures without unnecessary false alarms. Continuously, the system monitors the condition of the bushings. Using the patented MR-2/3 reference algorithm in combination with the reference voltage method, the system triggers a warning or an alarm based on the changes in capacitance and additionally the dissipation factor (tan δ) when the limit value is exceeded.