Reliability of parallel connected power transformers with failure correlation and its preventive maintenance

Abstract

This paper studies reliability of power substation with parallel connected power transformers and its preventive maintenance strategy. The processes of transformers failure are modeled by Poisson processes with correlation. Representing by multi-Gaussian Copula function, the mathematical formula of reliability of three power transformers connected parallel is given, and the reliability of substation with preventive maintenance schedule is studied. By the mean of Monte Carlo simulation, the reliability of three power transformers parallel connected is calculated, and its preventive maintenance schedule is discussed. The research of the paper shows that the failure correlation of transformers is key factor to the preventive maintenance schedule.

Distribution Transformer Synchronization Simulation with Two Different Vector Groups using the Matlab Simulink

“…Which is indicated by the loss of voltage and the loss of the angle difference of each phase, if under normal circumstances the difference between each phase in a 3-phase transformer is 120°. c. Transformers that have different vector groups (Dyn5 and Dyn11) can be synchronized, without changing the connection in the transformer windings (vector group) by changing the position of the cable connection on one of the transformers, namely the position of the high-voltage cable (20 kV) and the position of the low-voltage cable connection (0,4 kV), with the arrangement according to figure (15) where for the high voltage side (Dyn11) phase R and phase T are exchanged, while on the low voltage side the voltage side (Dyn11) phase r and phase s are exchanged. Changes in the position of the HV and LV cable connections, resulting in a phase shift between the Dyn5 transformer and the Dyn11 transformer, so that during synchronization there will be no interference because there is no difference in the angle of the transformer.…”