A switch cabinet fault diagnosis method based on an on-line indirect temperature measurement mode

Abstract

The invention discloses a switch cabinet fault diagnosis method based on an on-line indirect temperature measurement mode. Judgment of fault states of the switch cabinet is conducted through temperature real-time monitoring carried out on an indirect temperature measurement point and an environmental temperature measurement point used for installation of temperature measurement sensors on the outside of the switch cabinet. According to the method, physical modeling and measurement point selection are firstly carried out; a temperature theta[2](t) of the indirect temperature measurement point and the temperature theta[0](t) of the environmental temperature measurement point are measured in real time; then a temperature theta[1](t) of a lumped heat source center inside the switch cabinet and a load ideal temperature theta[1](t)[LX] of the lumped heat source center and / or a determined load ideal temperature theta[2](t)[LX] of the indirect temperature measurement point are calculated; the measured temperature and the temperature obtained through calculating are compared with thresholds in a fault judgment standard to finally give a fault state diagnosis. The indirect temperature measurement method is employed in the invention to substitute for a complex and expensive direct temperature measurement mode. The operation is simple and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of fault diagnosis of power switch cabinets, in particular to a fault diagnosis method for switch cabinets based on an online indirect temperature measurement method. Background technique [0002] In the power system, the switchgear is responsible for the dual functions of closing and disconnecting the power lines and protecting the safety of the system. With the rapid development of the power system towards high voltage, large units and large capacity, the power grid is expanding day by day and the substation unattended management mode With the popularization and promotion of integrated automation, the safe operation of switchgear is becoming more and more important. When the knife contacts in the switch cabinet and the joints of the incoming and outgoing lines of the power cable are in poor contact, the contact resistance will increase, and heat will be generated when the load current flows. Overheating wi...

AI Technical Summary

Problems solved by technology

However, to install any temperature measuring sensor at the electrical contact position in the cabinet, there are many restrictions, such as: the limitation of installing temperature measuring equipment in the switch cabinet when the power is cut off, the limitation of the space structure in the cabinet, the limitation of the electrical clearance, and the tolerance of the sensor. The limitation of high voltage and strong magnetic field, the limitation of sensor's high temperature resistance, the limitation of sensor power supply and communication line wiring, the influence of wireless signal transmission shielding, etc., make the installation and popularization of switchgear temperature sensor very difficult and costly

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