Relay maintenance generally consists of : Inspection and burnishing of contacts. Adjustments checking (iv) Breakers tripped by manual contact closing. Facilities need to perform installation tests, implement preventive maintenance programs, and. Monitoring system for fast event recognizing allows operators, maintenance staff and production supervisors to prevent or fix effectively downtime issues as they happen, instead of weeks later. Rare operation, critical function: Protective relays may operate only once every several. ABB has developed a preventive maintenance concept for the well-established SPACOM, RE500 and Relion series relays. These relays have been in the market for more than 20 years. Setting determines pick-up value/time.