阅读说明：本技术 一种基于静稳阻抗圆的汽轮发电机低励限制曲线整定方法 (Turbine generator low excitation limit curve setting method based on static stability impedance circle ) 是由 张明江 崔佳鹏 穆兴华 董尔佳 董一凡 陈晓光 师广志 关万琳 荣爽 刘进 胡远 于 2019-10-31 设计创作，主要内容包括：一种基于静稳阻抗圆的汽轮发电机低励限制曲线整定方法,涉及一种汽轮发电机励磁调节器低励限制曲线确定方法,本发明解决了现有汽轮发电机进相控制深度控制准确性差,且整定复杂,易出现失磁保护与低励限制曲线匹配失误,导致失磁误动停机的问题。本发明利用汽轮发电机的静态稳定极限参数,获得阻抗坐标系下汽轮发电机静稳阻抗圆方程；其中,阻抗坐标系的横坐标为电阻R,纵坐标为电抗X；利用所述汽轮发电机静稳阻抗圆方程,对汽轮发电机低励限制阻抗圆方程进行整定；利用所述汽轮发电机低励限制阻抗圆方程绘制汽轮发电机低励限制曲线。本发明适用于控制汽轮发电机进相。(The invention discloses a turbine generator low excitation limit curve setting method based on a static stability impedance circle, relates to a turbine generator excitation regulator low excitation limit curve determination method, and solves the problems that the existing turbine generator is poor in control depth control accuracy of an inlet phase, complex in setting, prone to causing mismatching of a magnetic loss protection curve and a low excitation limit curve, and prone to causing magnetic loss misoperation and stopping. The static stability impedance circular equation of the steam turbine generator under an impedance coordinate system is obtained by utilizing the static stability limit parameter of the steam turbine generator; wherein, the abscissa of the impedance coordinate system is resistance R, and the ordinate is reactance X; setting a low excitation limiting impedance circular equation of the steam turbine generator by using the static stable impedance circular equation of the steam turbine generator; and drawing a low excitation limit curve of the steam turbine generator by using the low excitation limit impedance circular equation of the steam turbine generator. The method is suitable for controlling the phase advance of the turbonator.)

1. A turbine generator low excitation limit curve setting method based on a static stability impedance circle is characterized by comprising the following steps:

the method comprises the following steps that firstly, a static stability impedance circular equation of the steam turbine generator under an impedance coordinate system is obtained by utilizing static stability limit parameters of the steam turbine generator; wherein, the abscissa of the impedance coordinate system is resistance R, and the ordinate is reactance X;

setting a turbine generator low excitation limited impedance circular equation by using the turbine generator static stable impedance circular equation obtained by calculation in the step one; drawing a low excitation limit curve of the steam turbine generator by using the low excitation limit impedance circular equation of the steam turbine generator;

wherein the low excitation limited impedance circle of the steam turbine generator is concentric with the static stable impedance circle of the steam turbine generator,

the turbine generator static stability impedance circle is positioned in the turbine generator low excitation limited impedance circle;

the difference between the radius of the turbine generator static stable impedance circle and the radius of the turbine generator low excitation limited impedance circle is determined by a setting coefficient K_kAnd (6) determining.

2. The method for setting the low excitation limit curve of the steam turbine generator based on the quiet impedance circle of claim 1, wherein in the first step, the quiet stability limit parameter of the steam turbine generator is:

U_Nrated voltage of the generator in kV;

S_Nrated apparent power for the generator, MVA;

X_dcalibrating the value of the generator synchronous reactance;

X_conthe normalized value is the link reactance between the generator and the system;

n_vthe transformation ratio of a generator terminal voltage transformer is obtained;

n_athe transformation ratio of the current transformer at the generator terminal is shown.

3. The turbine generator under-excitation limit curve setting method based on the quiet impedance circle of claim 1 or 2, wherein in the first step, the turbine generator quiet impedance circle equation under the impedance coordinate system is:

wherein a is the center of a circle, and r is the radius of the turbine generator static stable impedance circle.

4. The method for setting the low excitation limit curve of the steam turbine generator based on the quiet impedance circle of claim 3, wherein the equation of the low excitation limit impedance circle of the steam turbine generator in the second step is as follows:

wherein, the static stable impedance circle of the turbonator is concentric a_{Is low in}A; radius of low excitation limiting impedance circle of steam turbine generator: r is_{Is low in}＝K_k·r。

5. The method for setting the low excitation limit curve of the steam turbine generator based on the quiet impedance circle as claimed in claim 1 or 4, wherein the setting coefficient K is_kThe value range of (A): k is more than or equal to 1.1_k≤1.3。

Technical Field

The invention relates to a method for determining a low excitation limit curve of an excitation regulator of a steam turbine generator.

Background

When the steam turbine generator is in phase-in operation, the low excitation limiting curve under the impedance coordinate system changes due to the change of random terminal voltage, active power and reactive power, the phase-in depth is often difficult to control, the setting is complex, and the problem of mismatching of the magnetic loss protection and the low excitation limiting curve is easy to occur, so that the magnetic loss misoperation halt is caused.

Disclosure of Invention

The invention provides a turbine generator low excitation limiting curve setting method based on a static stability impedance circle, and aims to solve the problems that the existing turbine generator is poor in accuracy of phase-inlet control depth control, complex in setting and prone to causing mismatching of magnetic loss protection and a low excitation limiting curve, and accordingly magnetic loss misoperation shutdown is caused.

The invention relates to a turbine generator low excitation limit curve setting method based on a static stability impedance circle, which comprises the following steps:

the method comprises the following steps that firstly, a static stability impedance circular equation of the steam turbine generator under an impedance coordinate system is obtained by utilizing static stability limit parameters of the steam turbine generator; wherein, the abscissa of the impedance coordinate system is resistance R, and the ordinate is reactance X;

setting a turbine generator low excitation limited impedance circular equation by using the turbine generator static stable impedance circular equation obtained by calculation in the step one; drawing a low excitation limit curve of the steam turbine generator by using the low excitation limit impedance circular equation of the steam turbine generator;

wherein the low excitation limited impedance circle of the steam turbine generator is concentric with the static stable impedance circle of the steam turbine generator,

the turbine generator static stability impedance circle is positioned in the turbine generator low excitation limited impedance circle;

the difference between the radius of the turbine generator static stable impedance circle and the radius of the turbine generator low excitation limited impedance circle is determined by a setting coefficient K_kDetermination of said K_kSet in the excitation adjusting device.

Further, the static stability limit parameter of the turbonator in the step one is as follows:

U_Nrated voltage of the generator in kV;

S_Nrated apparent power for the generator, MVA;

X_dcalibrating the value of the generator synchronous reactance;

X_conthe normalized value is the link reactance between the generator and the system;

n_vthe transformation ratio of a generator terminal voltage transformer is obtained;

n_athe transformation ratio of the current transformer at the generator terminal is shown.

Further, in the first step, the turbine generator static stability impedance circular equation under the impedance coordinate system is as follows:

wherein a is the center of a circle, and r is the radius of the turbine generator static stable impedance circle.

Further, the low excitation limited impedance circular equation of the steam turbine generator in the second step is as follows:

wherein, the static stable impedance circle of the turbonator is concentric a_{Is low in}A; radius of low excitation limiting impedance circle of steam turbine generator: r is_{Is low in}＝K_k·r。

Further, the setting coefficient K_kThe value range of (A): k is more than or equal to 1.1_k≤1.3。

The method utilizes the static stability limit parameter of the steam turbine generator to obtain the static stability impedance circular equation of the steam turbine generator under the impedance coordinate system, and then utilizes the curve of the static stability impedance circular equation of the steam turbine generator to draw and set the low excitation limiting impedance circular curve of the steam turbine generator, thereby effectively realizing the low excitation limiting action when the impedance enters the low excitation limiting impedance circle of the steam turbine generator and preventing the phase-entering depth from increasing; the defect of the low excitation limit curve of the conventional turbonator is overcome, and the conversion of a coordinate plane is not needed when the matching relation of the loss of excitation protection and the low excitation limit curve is checked.

The low excitation limiting curve determined by the static stable impedance circle is more accurate, the method is visual and clear, the setting is simple, and the demagnetization protection can be effectively prevented from being prior to the low excitation limiting action.

Drawings

FIG. 1 is a diagram of the relationship between the turbine generator quiet impedance circle and the turbine generator low excitation limiting impedance circle in an impedance coordinate system.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.