engleski

Operating experience with a transient overvoltages monitoring system installed on power transformers and shunt reactors

Transient overvoltages generated by lightning strikes or switching operations represent a significant risk to insulation system of power transformers and shunt reactors. Since the exposure of equipment to overvoltages during operation and the overvoltage amplitudes are usually unknow, an on-line overvoltage transient recorder is used with the ability to sample, analyse and store transients at transformer terminals in real-time. In this paper, transient overvoltage monitoring system is presented. Overvoltages are measured on the outside measurement terminal of the shunt reactor and transformer bushing. Operating experience regarding the application of monitoring systems in field is described including different cases of lightning and switching overvoltages. Lightning overvoltages recorded by monitoring system are correlated with data from the lightning location system (LLS). Switching overvoltages recorded on the shunt reactor are compared with numerical simulations in EMTP-RV software. Collected data about overvoltage stresses can be used as the basis for the assessment of the transformer and shunt reactor insulation condition and estimation of health index.

Transient overvoltage monitoring system ; Lightning and switching overvoltages ; Power transformers ; Shunt reactors

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