High voltage converter with differential protection

Abstract

The invention discloses a high voltage converter with differential protection, which comprises a power supply unit, a power module, a signal acquisition unit, a signal processing unit, a CPU (Central Processing Unit), a control unit, an input / output interface and a controlled motor, wherein the signal acquisition unit comprises three current transformers, an inlet wire and an outlet wire at each phase of the three-phase controlled motor both pass through one same current transformer, and the three outlet wires of the three-phase controlled motor are in short connection after passing through the current transformers; and the current signals measured by the three current transformers are sent to the CPU after processing, the CPU monitors the change condition of the current signals in real time, and when the CPU monitors that the changes of the current signals exceed a preset value, the CPU sends out a protection action signal through the input / output interface. The invention not only can realize real-time protection but also consumes less materials and has reliable property when a high-capacity high-voltage motor adopts a transducer for power supply with the working frequency of 25-40Hz.

Description

[technical field] [0001] The invention relates to frequency conversion speed regulation control of a high-voltage motor, in particular to a high-voltage frequency conversion speed regulation device with differential protection. [Background technique] [0002] High-voltage frequency conversion speed control devices have been widely used in metallurgy, non-ferrous metals, petrochemicals, electric power, machinery, building materials, ports and wharves and other industries. [0003] 1. For large-capacity high-voltage motors, it is difficult to understand the insulation conditions inside the windings, and it is not easy to find internal short-circuit faults. Due to the complex structure of large-capacity motors, short-circuit faults are more likely to occur. Large-capacity motors are expensive and have large losses, so large-capacity motors are equipped with differential protection devices that monitor the internal faults of the motor windings. purpose of short circuit protecti...

AI Technical Summary

Problems solved by technology

[0006] (1) Two sets of transformers with exactly the same performance are required, not only consumes a lot of materials, but also the difference in the performance of the transformers will cause malfunctions

[0007] (2) Generally, the switch cabinet is far away from the motor, and the conventional differential protection requires that the differential cable section is thick and uneconomical

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