Modeling method of thermal power unit's low-order frequency response considering heat storage dynamics

Abstract

The invention discloses a thermal power generating unit low-order frequency response modeling method considering thermal storage dynamics. The method comprises the following steps that: S1: accordingto the mathematical models of a boiler module, a steam turbine module and a power generation module, establishing a thermal power generating unit low-order frequency response model considering the thermal storage dynamics, wherein the thermal power generating unit low-order frequency response model comprises a thermal power generating unit revolving speed feedback low-order frequency response model considering the thermal storage dynamics, and a thermal power generating unit power frequency feedback low-order frequency response model considering the thermal storage dynamics; S2: carrying out time domain analytic expression on the thermal power generating unit low-order frequency response model, which is established in the S1, considering the thermal storage dynamics so as to evaluate a disturbed unit dynamic frequency response process. By use of the method, the boiler module is simplified and is imported into a frequency response module to form the thermal power generating unit low-order frequency response model considering the thermal storage dynamics so as to accurately describe the frequency response process of the unit.

Description

technical field [0001] The invention relates to the field of frequency response modeling of a thermal power unit in an electric power system, in particular to a low-order frequency response modeling method of a thermal power unit considering thermal storage dynamics. Background technique [0002] With the gradual advancement of UHV power transmission projects, the proportion of renewable energy capacity continues to increase, and the problem of frequency stability has become increasingly prominent. As the first line of defense for frequency control, frequency response is the key measure to prevent the frequency from dropping sharply in the absence of high power. [0003] In the current research on the frequency response modeling of thermal power units, the influence of boiler heat storage dynamics on the frequency response of the unit is generally not considered, which implicitly assumes that the heat storage of the unit is very sufficient, and the main steam pressure remain...

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Problems solved by technology

[0003] In the current research on the frequency response modeling of thermal power units, the influence of boiler heat storage dynamics on the frequency response of the unit is generally not considered, which implicitly assumes that the heat storage of the unit is very sufficient, and the main steam pressure remains unchanged during the disturbance process. The prime mover output is only positively correlated with its valve opening

However, in actual operation, the change of unit valve opening caused by the lack of high power of the system will cause fluctuations in the main steam pressure, thereby changing the linear relationship between the output of the governor and the valve opening.

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