Excitation loss protection method in synchronization unit starting process

Abstract

Disclosed is an excitation loss protection method in the synchronization unit starting process. The excitation loss protection method in the synchronization unit starting process comprises the steps of measuring voltage and current of a port of a starting unit in real time; seen from the port to the interior of the unit, enabling the unit which is started to be equivalent to a model connected with a resistor and an inductor in series, wherein the voltage and current of the unit obtained through real-time measurement by a measuring device are sampling values; on the basis of the principle of least squares, calculating the sampling values, and obtaining estimated values of the equivalent resistance and the induction seen from the port of the unit; according to the calculation result of the equivalent resistance and induction obtained through calculation of the estimated values, judging whether the result value enters an action area or not; if the result value enters the action area, determining that an excitation loss fault happens on the starting unit; if not, no excitation loss fault happens on the starting unit. According to the excitation loss protection method in the synchronization unit starting process, the frequency in the starting process is not calculated, the resistance and induction change trajectories can be directly calculated under the time domain condition through the resistance and induction equivalent model, frequency estimation is avoided, and the excitation loss protection method is applicable to the occasion that the frequency of the unit continuously changes in the starting process.

Description

technical field [0001] The invention relates to a method for protection against demagnetization. In particular, it relates to a method for protection against demagnetization in the starting process of a synchronous unit. Background technique [0002] Back-to-back starting and inverter starting are the two main starting methods for synchronous units. The so-called back-to-back start refers to directly connecting the synchronous generator and the synchronous motor, and using the generator to directly drive the motor until the motor speed reaches the synchronous speed that can be connected to the grid. Inverter starting is to use the low-frequency power provided by the frequency conversion speed regulation system to add to the stator of the started unit, and the synchronous unit will gradually increase in speed under the action of synchronous torque until it can be connected to the grid. There are obvious differences between the loss-of-excitation fault during the start-up of...

AI Technical Summary

Problems solved by technology

[0008] At present, there are demagnetization fault detection methods, but they are all aimed at the demagnetization fault detection of the synchronous unit during normal operation, and the demagnetization fault during the starting process lacks an effective detection method

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