Monitoring system of internal temperature and stress of power transformer winding and monitoring method thereof

Abstract

The invention provides a monitoring system of the internal temperatures and the stress of a power transformer winding and a monitoring method thereof. The system comprises a laser light source, an optical fiber sensor, a frequency shift detection circuit, an amplification circuit, a filer sampling circuit and a monitor, wherein light emitted by the laser light source passes through the optical fiber sensor and generates Brillouin scattering, the optical fiber sensor is pre-embedded in an electromagnetic line of the power transformer winding, the internal temperature and the stress of the power transformer winding influence the frequency of a Brillouin scattering signal of the optical fiber sensor, and the Brillouin scattering signal which is transmitted back by the optical fiber sensor is converted into an electric signal by the frequency shift detection circuit, passes through the amplification circuit and the filer sampling circuit to acquire the information of distributed temperature and stress in the winding and finally transmitted to the monitor to be displayed. The monitoring system of the invention can accurately measure the temperature and the stress of various points in the transformer winding and truly reflects the temperature of the hottest point and the stress of the winding due to deformation.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing in power transformer monitoring, and in particular relates to a monitoring system and a monitoring method for internal temperature and stress of power transformer windings. Background technique [0002] At present, there are mainly three methods for measuring the temperature of power transformer coil windings at home and abroad: the first is to measure the surface temperature of power transformer winding coils through sensors installed on the surface of transformer winding coils, but this method can only measure the surface temperature of power transformer windings. It cannot truly reflect the temperature of the hottest point of the winding. The second is to indirectly measure the internal temperature of the power transformer winding coil by measuring the medium temperature. It has been proved by engineering practice that the internal coil temperature of the winding obtained by this method is ...

AI Technical Summary

Problems solved by technology

[0002] At present, there are mainly three methods for measuring the temperature of power transformer coil windings at home and abroad: the first is to measure the surface temperature of power transformer winding coils through sensors installed on the surface of transformer winding coils, but this method can only measure the surface temperature of power transformer windings. Failure to truly reflect the hottest point temperature of the winding

The second is to indirectly measure the internal temperature of the power transformer winding coil by measuring the temperature of the medium. It has been proved by engineering practice that the internal coil temperature of the winding obtained by this method is not accurate.

The third is to measure the internal temperature of the power transformer winding coil through a relatively complex fiber grating sensor. The installation of the grating sensor in this method is complicated and the measurable points are limited.

However, the measurement of the internal stress of the coil winding at home and abroad can only be measured indirectly through the winding deformation test device, that is, the winding deformation meter, which not only cannot reflect the stress change of the winding in real time, but also easily leads to misjudgment due to the low repetition rate of the measurement results.

Images