Control parameter setting method for steam turbine speed governing system

Abstract

The invention relates to a control parameter setting method for a steam turbine speed governing system. The control parameter setting method comprises the following steps: (1) building a mathematical model and a transfer function of the steam turbine speed governing system provided with a stand-alone infinitely great system in a power network model; (2) when the control parameters Ki and Kp change within the range of 0-10, unceasingly working out the numerical solutions of the characteristic roots of the transfer function of the system under the given parameters, and the expression of the characteristic root is s=A+Bj; (3) working out the value of the characteristic parameter Xi of each group of the characteristic roots, and obtaining the minimum value of Xi; (4) drawing the tendency chart of the minimum value of the characteristic parameter Xi of each group varying along with the control parameters Ki and Kp; (5) judging whether the system is stabilized on the basis of the positive or negative values of the characteristic parameter Xi, acquiring the value range of the control parameters that stabilize the system, and conducting fine adjustment by adopting the cut-and-try method to set up the optimal control parameter that is veritably practical to a machine set. The control parameter setting method has significance on further normalizing the parameter arrangement of a steam turbine control system and reducing the low-frequency oscillation of the system.

Description

technical field [0001] The invention belongs to a control method for speed regulation of a steam turbine and a safe and stable operation of a power grid, in particular to a method for setting parameters of a steam turbine controller in the field of improving the dynamic stability of a power system and preventing low-frequency oscillation of the power grid. Background technique [0002] In recent years, as my country's electricity demand has increased year by year, the scale of the power system has become larger and larger, and the power transmitted on the main transmission line has also continued to increase. The operating conditions of the entire power system have become increasingly harsh, and low-frequency oscillations occur from time to time. It is one of the important factors restricting the power transmission of the tie line and the safe and stable operation of the interconnected grid. Due to several low-frequency oscillation accidents caused by the power supply side in...

AI Technical Summary

Problems solved by technology

Some experts analyzed the influence of main parameters on the damping characteristics of the power grid by using the simplified model of the speed control system, and pointed out that the improper setting of the proportional coefficient in the controller will lead to a negative damping effect after the primary frequency regulation circuit is put into operation, resulting in low-frequency oscillation of the power grid

However, there is still a lack of research on how controller parameter changes will affect system stability, and how to give a reasonable range of controller parameters based on power system stability analysis.

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