Method and Apparatus for Leakage Monitoring for Oil-Immersed Electrical Transformers

摘要

The present invention comprises an apparatus and method for detecting a loss of oil from an oil-immersed transformer, based on fitting a transformer top-oil temperature model to online measurements in an iterative optimization process that yields fitted values for a first model parameter representing the top-oil temperature rise over ambient temperature and a second model parameter representing the oil time constant. Among the several advantages seen in the contemplated apparatus and method is the reduction in required instrumentation, whereby transformer oil leaks are indirectly detected without requiring pressure sensors or mechanical floats, although the presence of such sensors is not excluded by the teachings herein.

主权项

1. A method of monitoring for oil leakage from an oil-immersed electrical transformer comprising:
determining characteristic values for the transformer, for first and second parameters of a top-oil temperature model, wherein the first parameter represents the top-oil temperature rise over ambient temperature and the second parameter represents the oil time constant; obtaining online measurements for the transformer, including an ambient temperature measurement, a top-oil temperature measurement and a winding current measurement; fitting the transformer top-oil temperature model to the online measurements in an iterative optimization process to obtain fitted values for the first and second parameters; estimating a transformer oil thermal capacitance as a function of the fitted values and correspondingly estimating a transformer oil weight as a function of the estimated transformer oil thermal capacitance; and generating alarm signaling based on comparing the estimated transformer oil weight to a characteristic transformer oil weight, as calculated from the characteristic values.