CN111075649A - An active load shedding control method for wind turbines based on external wind conditions - Google Patents

Abstract

The invention discloses an active load reduction control method of a wind generating set based on external wind conditions, which comprises the following steps: 1) the wind condition severity coefficient is output by processing the real-time wind speed and the real-time wind direction collected by a wind speed and anemoscope; 2) the real-time fore-and-aft vibration and the left-and-right vibration of the tower, which are collected by a vibration sensor, are processed, and a vibration severity coefficient is output; 3) outputting a set maximum power set value through a wind condition severity coefficient obtained by wind condition evaluation calculation and a vibration severity coefficient obtained by vibration evaluation calculation; 4) limiting the set value of the maximum power of the set to the set value output in the step 3) so as to reduce the generating power of the set and realize the active load reduction of the set. The method actively reduces the generating power of the unit, thereby reducing the wind load of the impeller surface, finally reducing the amplitude of the vibration of the tower and further avoiding the generating capacity loss caused by unnecessary halt inspection.

Description

Active load reduction control method of wind generating set based on external wind conditions

Technical Field

The invention relates to the technical field of load shedding control of wind generating sets, in particular to an active load shedding control method of a wind generating set based on external wind conditions.

Background

High-quality wind field resources with flat terrain and high annual average wind speed are less and less, more and more wind power plants are built in mountainous areas with complex terrain, and the wind conditions are much worse than those of plain wind fields. When the unit operates under the working condition with large changes of wind speed and wind direction, the stability of the unit is reduced, the vibration amplitude of the tower is an important index for measuring the stability of the unit, and when the vibration amplitude of the tower monitored by the vibration sensor exceeds a unit safety threshold, the unit is triggered to be stopped due to faults. As the vibration amplitude of the tower exceeds the limit and relates to the safe operation of the whole machine, the safe operation manual for a plurality of wind fields with faults stipulates that field operation and maintenance personnel are not allowed to directly reset and start the machine, and the machine can be reset and started only by driving the vehicle to a machine position and climbing the tower to carry out various safety checks and confirming that relevant parts of a machine set are abnormal. From the triggering of vibration fault shutdown to the tower climbing inspection fault resetting startup, the time is as short as several hours, and the time is longer when the machine is far away, the road condition is bad, the fault is triggered at night and the like. The long-time shutdown means that more generated energy is lost, so that the reduction of the vibration fault shutdown of the unit becomes a hot spot problem in the current wind power control field. The vibration of the tower of the unit is out of limit, and the following reasons are generally adopted:

1. abnormality of unit hardware: if the blade is greatly damaged or broken, the imbalance of wind load on the impeller surface is caused, and the vibration of the tower is over-limited.

2. The unit control strategy is abnormal: if the variable pitch control loop is unstable, the variable pitch mechanism executes an abnormal variable pitch instruction to cause the vibration of the tower to exceed the limit.

3. The external wind condition is severe: such as wind speed and wind direction, change greatly in a short time, resulting in the wind load on the impeller surface changing greatly, and causing the vibration of the tower to exceed the limit.

The 1 st point and the 2 nd point in the reasons that the vibration of the tower of the unit exceeds the limit at the 3 rd point are actually required to be stopped for fault treatment, and the 3 rd point causes the vibration of the tower of the unit to exceed the limit and the fault stop is to some extent a safety protection stop and is not a unit fault stop due to poor external wind conditions. More than 90% of vibration faults in the actual running process of the unit are caused by bad external wind conditions, so that the problem that how to avoid the problem that the stable running of the unit under the bad wind conditions does not trigger the vibration overrun shutdown of a tower of the unit becomes a hot point problem for the research of various current large-fan manufacturers is solved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a feasible active load reduction control method of a wind generating set based on external wind conditions.

In order to achieve the purpose, the technical scheme provided by the invention is as follows: a wind generating set active load reduction control method based on external wind conditions comprises the following steps:

1) wind condition assessment

The real-time wind speed and wind direction collected by the wind speed and wind direction instrument are processed to output a wind condition severity coefficient K_{Wind power}＝K_{Wind speed}*K_{Wind direction}Wherein:

in the formula, the unit of wind speed is m/s, and the unit of wind direction is degree; k_{Wind speed}、K_{Wind direction}Is a function limt [ m x n ]]Wherein limt [ mxn ] is when x is not more than m]When m is equal to m<x<n is limt [ m x n [ ]]X, limt [ m x n ] when x ≧ n]＝n；A_{Wind speed}、B_{Wind speed}、C_{Wind direction}Is a fixed parameter value;

2) vibration assessment

Real-time tower front-back vibration and left-right vibration collected by a vibration sensor are processed to output a vibration severity coefficient K_VibrationWherein:

wherein the unit of vibration is m/s²；D_Vibration、E_VibrationIs a fixed parameter value;

3) maximum power set point estimation

Wind condition severity coefficient K obtained through wind condition evaluation calculation_{Wind power}And a vibratorVibration severity coefficient K obtained by dynamic evaluation calculation_VibrationOutputting set maximum power set value P_maxWherein:

P_max＝limt[0.6 1.6-K_{wind power}*K_Vibration1]*P_{Rated value}

In the formula, P_{Rated value}The rated power of the unit;

4) limiting the maximum power set value of the unit to P_maxThe power generation power of the unit is reduced, so that the load of the impeller surface of the unit is reduced, the vibration amplitude of the tower of the unit is ensured to be within a safety threshold value, and the power generation loss caused by long-time fault shutdown of the unit is avoided.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. under the condition of severe wind conditions, before the vibration amplitude of the tower of the unit does not reach the shutdown threshold value, the generating power of the unit is reduced in advance, the load of the impeller surface is reduced, the vibration amplitude of the tower of the unit is further ensured to be within the safety threshold value, and the generated energy loss caused by long-time fault shutdown of the unit is avoided.

2. Under the condition of severe wind conditions, before the vibration amplitude of the tower of the unit does not reach the shutdown threshold value, the generating power of the unit is reduced in advance, various limit loads of the unit are reduced, the healthy and stable operation of the unit is further ensured, and the service life of the unit is prolonged.

Drawings

FIG. 1 is a logic diagram of a control strategy of the present invention.

Detailed Description

The present invention will be further described with reference to the following specific examples.

As shown in fig. 1, the active load shedding control method for a wind turbine generator set based on an external wind condition provided in this embodiment includes the following steps:

1) wind condition assessment

The real-time wind speed and wind direction collected by the wind speed and wind direction instrument are processed to output a wind condition severity coefficient K_{Wind power}＝K_{Wind speed}*K_{Wind direction}Wherein:

in the formula, the unit of wind speed is m/s, and the unit of wind direction is degree; k_{Wind speed}、K_{Wind direction}Is a function limt [ m x n ]]Wherein limt [ mxn ] is when x is not more than m]When m is equal to m<x<n is limt [ m x n [ ]]X, limt [ m x n ] when x ≧ n]＝n；A_{Wind speed}、B_{Wind speed}、C_{Wind direction}Is a fixed parameter value.

2) Vibration assessment

Real-time tower front-back vibration and left-right vibration collected by a vibration sensor are processed to output a vibration severity coefficient K_VibrationWherein:

wherein the unit of vibration is m/s²；D_Vibration、E_VibrationIs a fixed parameter value.

3) Maximum power set point estimation

Wind condition severity coefficient K obtained through wind condition evaluation calculation_{Wind power}And the vibration severity coefficient K obtained by vibration evaluation calculation_VibrationOutputting set maximum power set value P_maxWherein:

P_max＝limt[0.6 1.6-K_{wind power}*K_Vibration1]*P_{Rated value}

In the formula, P_{Rated value}The rated power of the unit.

4) Limiting the maximum power set value of the unit to P_maxThe power generation power of the unit is reduced, so that the load of the impeller surface of the unit is reduced, the vibration amplitude of the tower of the unit is ensured to be within a safety threshold value, and the power generation loss caused by long-time fault shutdown of the unit is avoided.

In summary, after the active load reduction control strategy of the wind generating set provided by the invention is adopted, under the condition of severe wind conditions and before the tower vibration amplitude of the set does not reach the shutdown threshold, the generated power of the set is reduced in advance, so that the load of the wheel face and each limit load of the set can be reduced, the vibration amplitude of the tower of the set is ensured to be within the safety threshold and the set can run healthily and stably, the generated energy loss caused by long-time fault shutdown of the set is avoided, the service life of the set is prolonged, and the active load reduction control strategy is worthy of popularization.

The above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, so that the changes in the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims (1)

1. A wind generating set active load reduction control method based on external wind conditions is characterized by comprising the following steps:

1) wind condition assessment

The real-time wind speed and wind direction collected by the wind speed and wind direction instrument are processed to output a wind condition severity coefficient K_{Wind power}＝K_{Wind speed}*K_{Wind direction}Wherein:

in the formula, the unit of wind speed is m/s, and the unit of wind direction is degree; k_{Wind speed}、K_{Wind direction}Is a function limt [ m x n ]]Wherein limt [ mxn ] is when x is not more than m]When m is equal to m<x<n is limt [ m x n [ ]]X, limt [ m x n ] when x ≧ n]＝n；A_{Wind speed}、B_{Wind speed}、C_{Wind direction}Is a fixed parameter value;

2) vibration assessment

Real-time tower front-back vibration and left-right vibration collected by a vibration sensor are processed to output a vibration severity systemNumber K_VibrationWherein:

wherein the unit of vibration is m/s²；D_Vibration、E_VibrationIs a fixed parameter value;

3) maximum power set point estimation

Wind condition severity coefficient K obtained through wind condition evaluation calculation_{Wind power}And the vibration severity coefficient K obtained by vibration evaluation calculation_VibrationOutputting set maximum power set value P_maxWherein:

P_max＝limt[0.6 1.6-K_{wind power}*K_Vibration1]*P_{Rated value}

In the formula, P_{Rated value}The rated power of the unit;

4) limiting the maximum power set value of the unit to P_maxThe power generation power of the unit is reduced, so that the load of the impeller surface of the unit is reduced, the vibration amplitude of the tower of the unit is ensured to be within a safety threshold value, and the power generation loss caused by long-time fault shutdown of the unit is avoided.

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