Auxiliary limit control method and device for alternating-current excitation system of variable-speed pumped storage unit

Abstract

The invention discloses an auxiliary limit control method and device for an alternating-current excitation system of a variable-speed pumped storage unit. The auxiliary limit control method comprisesthe steps: obtaining a rotor d-axis excitation current reference value output by a constant-voltage control module; respectively calculating a rotor d-axis exciting current reference value when the exciting current is at the maximum value and the thermal limit value; when the inverse time limit action signal is 0, comparing the rotor d-axis exciting current reference value with the rotor d-axis exciting current reference value when the exciting current is at the maximum value, and taking the smaller one of the rotor d-axis exciting current reference value and the rotor d-axis exciting currentreference value as an auxiliary limited rotor d-axis exciting current reference value; and when the inverse time limit action signal is 1, comparing the rotor d-axis exciting current reference value with the rotor d-axis exciting current reference value when the exciting current is at the thermal limit value, and taking the smaller one of the rotor d-axis exciting current reference value and the rotor d-axis exciting current reference value as the rotor d-axis exciting current reference value for auxiliary limit. According to the auxiliary limit control method, the situation that the motor isdamaged due to winding overheating caused by long-time overcurrent of the rotor can be avoided.

Description

technical field [0001] The invention relates to an AC excitation system of a variable-speed pumped-storage unit, in particular to an auxiliary limiting control method and device for an AC excitation system of a variable-speed pumped-storage unit. Background technique [0002] Pumped storage power stations play an important role in peak load regulation and ensuring the stable operation of the power grid. They can promote the large-scale transmission and consumption of clean energy, and are one of the effective means to ensure the stable operation of the power system. The doubly fed variable speed pump storage unit (DFVSPSU-Doubly fed Variable Speed ​​Pump Storage Units doubly fed variable speed pump storage unit) adopts doubly fed induction motor, which has the ability to automatically track the frequency change of the power grid, and can operate within a certain range near the rated synchronous speed. Continuously variable speed operation, thus improving the ability to adjus...

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