Self-learning differential protection malfunction device for transformer of traction substation

Abstract

The invention provides a self-learning differential protection malfunction device for a transformer of a traction substation. The self-learning differential protection malfunction device comprises a main machine, wherein an operation board is arranged at the front side of the main machine; a baffle cover is arranged at the front part of the operation board; guide seats are arranged at two sides of the baffle cover in a matching manner; a guide groove matched with the side of the baffle cover is formed in the inner side of each guide seat; the guide seats are fixedly arranged on a housing of the main machine; lubricating grease box and an elastic bag are arranged at two sides of each guide seat; an outlet of each lubricating grease box is connected with one end of each elastic bag; the other end of each elastic bag is connected with the guide groove in each guide seat through a connection pipe; one-way valves are arranged at two ends of each elastic bag; a fixed plate is arranged at the upper part of each elastic bag; connection plates are arranged at two sides of the upper end of the baffle cover; draw bars parallel to the guide seats are arranged on the connection plates; a pressure plate is arranged at the lower end of each draw bar; each draw bar passes through the fixed plate; a screw is arranged on a cross plate of the baffle cover in the matching manner; the upper end of the screw is connected with a motor; a starting knob is arranged on the baffle cover, and controls the motor to start and steer; and the motor, the lubricating grease boxes and the fixed plates are arranged on the housing of the main machine.

Description

technical field [0001] The invention belongs to the field of electric equipment, in particular to a self-learning differential protection maloperation device used on a transformer of a traction substation. Background technique [0002] When the transformer is switched on without load, due to the saturation of the transformer iron core flux, the existence of residual magnetic flux and the nonlinear characteristics of the iron core material, an excitation inrush current with a relatively large amplitude will be generated, and it will reach a steady state after several cycles of transient process. , This impact closing current can often reach 6-8 times the rated current. In addition, the excitation inrush current will cause voltage fluctuations in this area, resulting in changes in the excitation current of transformers running in parallel with it, that is, the generation of inrush currents. This may cause misoperation of transformer differential protection, transformer insula...

AI Technical Summary

Problems solved by technology

The basic principle of phase selection closing is to select the appropriate voltage phase angle for closing according to the information of the last opening. However, due to the discreteness of the controller accuracy and the action time of the operating mechanism, it is difficult to ensure that the actual closing phase angle of the switch is the same as that of the switch. The theoretically calculated phase angles are completely equal, and the error directly determines the suppression effect of the excitation inrush current

[0005] At present, when operating the differential protection maloperation device, misoperation is easy to occur, and sometimes the operation purpose cannot be achieved, and even the opposite effect is caused in serious cases, and serious accidents occur

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