Time-varying Outage Model for Transformers Representing Internal Latent Fault
Zhang Jinjiang · Proceedings of the CSEE · 2013
Dissolved gases come into being in the insulating oil during the operation of power transformers.By experience,it is known that the health state of transformers can be deduced from the content of the dissolved gasses and the development of the internal latent fault in that state can be estimated by the generating rate of the gasses.Based on this knowledge,the time-varying outage model for risk assessment of transformers was built.The transformer state was firstly identified by the quantity of the dissolved gas.Thus the multi-state Markov model was set up considering the maintenances to get the basic failure rate.Meanwhile,the time-varying exponential outage model was established based on the gas generating rate which reflects the operating characteristics as well as the development of the latent fault.The model is validated by case studies and provides reference foundation for the device risk assessment.