A control method for thermal power generating units to respond to power grid low-frequency fault adjustment

Abstract

The invention discloses a control method of a thermal generator set in response to power grid low-frequency fault adjustment. When in response to the low-frequency fault of a power grid, the primary frequency adjustment function of the thermal generator set is greatly influenced. The control method includes acquiring a power grid frequency difference signal, determining whether the power grid frequency offset is lower than a low-frequency fault support threshold; if yes, evaluating the current low-frequency support capacity of the thermal generator set based on the frequency difference being lower than the subjection range of the low frequency fault support threshold, and rapidly cutting the extraction adjustable and extraction non-adjustable high-pressure heaters of the set by grading based on the evaluation result, and meanwhile, improving the set boiler instruction to a target value through load control means to complete the rapid response of the set under the large frequency difference of the power grid; and if no, performing primary frequency modulation of the set in a normal mode. The control method not only influences the function of the normal primary frequency modulation of the set, and can rapidly, stably, and enduringly provide power support when the power grid has low-frequency faults.

Description

technical field [0001] The invention relates to the field of thermal power generation control, in particular to a control method for a thermal power generation unit to quickly increase load through a fast switching and high-loading technology when a power grid has a low-frequency fault (frequency deviation is lower than -20r / min), and adjust in response to the power grid low-frequency fault. Background technique [0002] At present, in the process of implementing primary frequency regulation for basic auxiliary services for thermal power generating units, the primary frequency regulation capability required for power dispatch assessment is at most ±11r / min. With the continuous deepening of the UHV construction of the power grid, the single-unit capacity of the thermal power unit continues to expand, especially at the receiving end of the UHV. For the instantaneous large-scale power loss of the power grid, low-frequency faults occur in the power grid, which exceeds the maximum...

AI Technical Summary

Problems solved by technology

[0003] 1) The low-frequency fault of the power grid exceeds the adjustment capability of the thermal power generation unit, and the maximum frequency adjustment capability of the unit is not enough to make up for the gap in the power grid

[0004] 2) Large-scale thermal power generating units are generally super (super) critical DC units, which have the characteristics of no steam drum, small heat storage, sliding pressure operation, and large opening of the main engine control door. Before the arrival of low frequency, it is often accompanied by low frequency A poor frequency regulation action releases a large amount of heat storage of the unit, resulting in insufficient heat storage of the unit when a large frequency difference comes, which seriously affects the primary frequency regulation capability

Therefore, in general, when dealing with low-frequency faults in the power grid, the primary frequency regulation function of the thermal power generation unit is greatly affected, making the unit unable to play a supporting role in stabilizing the frequency of the power grid in a short time

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