CN103715700A - Reactive power control system and control method applicable to wind farm grid-connection point voltage control - Google Patents

Abstract

The present invention relates to a reactive power control system and control method applicable to the voltage control of the grid-connected point of a wind farm. The system includes a dispatching system, the dispatching system is connected to the AVC system of the wind farm, and the AVC systems of the wind farm are respectively connected to the centralized The SVC, the measuring device and the wind turbine SCADA system; the wind turbine SCADA system is connected to the wind turbines in the wind farm. The control method is as follows: through the size of the voltage sensitivity of the grid-connected point of the wind farm, determine the reactive power output adjustment sequence of the AVC system for the fans; according to whether the reactive power of each fan is controllable, determine the total number of reactive controllable fans in the wind farm The upper and lower limits of the adjustable total reactive power of the wind turbine; determine the total reactive power Q _reg that needs to be adjusted by the wind farm, and allocate the Q _reg according to the reactive power distribution strategy of the wind turbine first and then the SVC. The invention overcomes the shortcoming of long control cycle of the AVC system of the wind farm, and fully exerts the fast response adjustment ability of the SVC.

Description

Reactive power control system and control method suitable for voltage control of grid-connected point of wind farm

Technical field:

The present invention relates to a reactive power control system and a control method, and more specifically to a reactive power control system and a control method suitable for voltage control of a grid-connected point of a wind farm. the

Background technique:

In recent years, under the pressure of energy crisis and environmental pollution, wind power, as a clean and renewable energy, has developed rapidly in power generation. With the continuous increase of installed capacity of wind farms, the safe and stable operation of grid-connected wind farms and the power grids in the connected areas has attracted increasing attention. One of the important aspects is that random changes in wind power power pose a threat to the voltage stability of local power grids. The large-scale wind power grid connection will cause grid voltage fluctuations, especially the voltage fluctuations at the grid connection points of wind farms are the most prominent. In order to ensure the safe and stable operation of the power grid, the existing national standards and enterprise specifications for wind farms clearly require that wind farms must have corresponding reactive power control capabilities. the

Some wind farms newly put into operation have been equipped with reactive power control systems, which use the wind turbines and SVC devices in the wind farm to complete the safe and optimal control of the wind farm voltage. At present, the structure of the reactive power control system used in wind farms is basically the same. They collect the information of each wind turbine and SVC in the wind farm, and control the reactive power in the wind farm according to the dispatching instructions issued by the dispatching system according to different distribution strategies. distribute. This will cause two problems. One is that each control process needs to collect the information of the fan and SVC, and then perform calculations and issue control commands. Communication delays cause a relatively long control cycle and affect the control effect; Passively receiving commands issued by the AVC system for control greatly limits the ability of the SVC device to quickly adjust and respond to voltage. Third, the reactive power of the fan is frequently adjusted, which affects the safe and stable operation of the fan itself. the

Invention content:

The purpose of the present invention is to provide a reactive power control system and control method suitable for the voltage control of wind farm grid-connected points. The technical solution of the present invention overcomes the shortcoming of the existing wind farm AVC system with a long control period, and utilizes the reactive power output capability of wind turbines At the same time, give full play to the fast response adjustment ability of SVC, stabilize the voltage fluctuation range of the grid-connected point of the wind farm, and reduce the number of reactive power adjustments of the wind turbine. The reactive power reference value is set. the

In order to achieve the above object, the present invention adopts the following technical solutions: a reactive power control system suitable for the voltage control of the grid-connected point of the wind farm, the system includes a dispatching system, the dispatching system is connected to the automatic voltage control system of the wind farm, the wind power The field automatic voltage control system is respectively connected to the wind farm centralized reactive power compensation device, the measuring device and the wind turbine data acquisition and monitoring control system; the wind turbine data acquisition and monitoring control system is connected to the wind turbines with reactive power adjustment capabilities in the wind farm. the

The present invention provides a reactive power control system applicable to the voltage control of wind farm grid-connected points. The automatic voltage control system of the wind farm interacts with the dispatching system with the voltage dispatching command information issued by the dispatching system, and according to the dispatching needs, the The grid-connected point voltage, grid-connected point reactive power and reactive power information of each wind turbine sent to the dispatching system by the wind farm automatic voltage control system;

The interaction between the automatic voltage control system of the wind farm and the measuring device includes the information of the grid connection point voltage and reactive power of the wind farm sent by the measuring device to the automatic voltage control system of the wind farm;

The interaction between the wind farm automatic voltage control system and the wind turbine data acquisition and monitoring control system includes the reactive power control instructions sent by the wind farm automatic voltage control system to the wind turbine data acquisition and monitoring control system for each controllable wind turbine, The fan data acquisition and monitoring control system sends information on the operating status and reactive power of each fan to the automatic voltage control system of the wind farm;

The interaction between the automatic voltage control system of the wind farm and the centralized reactive power compensation device of the wind farm includes the reactive power control command sent by the automatic voltage control system of the wind farm to the centralized reactive power compensation device of the wind farm, and the centralized reactive power compensation device of the wind farm. The compensation device sends information about its operating status and reactive power to the automatic voltage control system of the wind farm;

The interaction between the measurement device and the centralized reactive power compensation device of the wind farm includes the information of the grid connection point voltage of the wind farm sent by the measurement device to the centralized reactive power compensation device of the wind farm. the

A control method of a reactive power control system suitable for wind farm grid-connected point voltage control provided by the present invention, the method includes the following steps:

(1) According to the ordering of the voltage sensitivity of the grid-connected point of the wind farm according to the reactive output of each fan in the wind farm, the automatic voltage control system of the wind farm adjusts the reactive output of the fan according to the order of sensitivity from large to small;

(2) Determine whether the reactive power of each fan is controllable;

(3) According to the reactive power controllable status of each wind turbine determined in the step (2), determine the total number of reactive power controllable wind turbines N _c of the entire wind farm, and then determine the adjustable total reactive power of the wind turbines in the wind farm. the upper and lower limits of the quantity;

(4) Comparing the target voltage U _ref of the grid-connected point of the wind farm issued by the dispatching system with the real-time voltage U _meas of the grid-connected point of the wind farm to obtain the voltage deviation value;

(5) Determine the total amount of reactive power Q _reg that needs to be adjusted by the wind farm, and allocate the total amount of reactive power Q _reg that needs to be adjusted by the wind farm according to the reactive power distribution strategy of the centralized reactive power compensation device of the wind farm after the wind farm .

Another preferred control method of a reactive power control system suitable for wind farm grid-connected point voltage control provided by the present invention, the process of determining the sensitivity is as follows:

According to the P-Q decomposition method in power flow calculation, in the P-Q decomposition method,

ΔQ=-B*ΔV (1)

Among them, B is the imaginary part of the admittance matrix of the grid-connected point of the wind farm and each fan node, ΔQ is the reactive power variation of the corresponding node, ΔV is the voltage variation of the corresponding node, and the above formula is changed to obtain

ΔV=-B ^-1 *ΔQ (2)

By determining the value of each column of each fan node in the row corresponding to the busbar of the grid-connected point in -B ^-1 , and comparing the value, the fan of the node with a large corresponding value is given priority to reactive power adjustment.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention, in the step (2), if the reactive power of each fan is controllable, set the corresponding fan Reactive power control flag C _flag = 1; if the reactive power of each fan is uncontrollable, set the reactive power control flag C _flag = 0 of the corresponding fan; if the following situation occurs, it is judged that the fan is uncontrollable, and C _flag is set =0, otherwise set C _flag =1;

The fan itself issues a fault alarm; or

The communication between the fan and the fan data acquisition and monitoring control system is interrupted; or

The fan cannot be controlled according to the reactive power command issued by the automatic voltage control system. the

Another preferred control method of the reactive power control system suitable for the voltage control of the grid-connected point of the wind farm provided by the present invention, the process of determining the upper and lower limits of the total amount of adjustable reactive power of the fan in the wind farm in the step 3 is:

The upper limit of the total reactive power of the fans in the wind farm Q _wc ^max =N _c *Q _wl ^max (3)

The lower limit of the adjustable total reactive power of the fans in the wind farm Q _wc ^min =N _c *Q _wl ^min (4)

In the formula, Q _wl ^min is the lower limit of reactive power of the fan, and Q _wl ^max is the upper limit of reactive power of the fan; then calculate the total amount of reactive power emitted by the reactive uncontrollable fan:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; wnc</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;Q</span>}}_{\mathrm{<span\; class="notranslate">\; meas</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

In the formula, It is the current reactive power of the fan whose reactive power control flag bit C _flag =0.

Another preferred control method of the reactive power control system suitable for wind farm grid-connected point voltage control provided by the present invention, the voltage deviation value in the step (4) is:

ΔU=|U _ref -U _meas | (6)

Set the dead zone U _dead1 for the voltage deviation value, so as to avoid the automatic voltage control system of the wind farm from frequently adjusting the equipment; if the voltage deviation value ΔU<U _dead1 , the automatic voltage control system of the wind farm will no longer The wind turbines in the field and the reactive power reference of the centralized reactive power compensation device in the wind farm are re-adjusted; if the voltage deviation value ΔU>U _dead1 , the automatic voltage control system of the wind farm will control the wind turbines and wind farms in the wind farm The reactive power reference of the centralized reactive power compensation device shall be re-adjusted.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention, when the voltage deviation value ΔU>U _dead1 , through the relationship between voltage and reactive power, calculate the wind farm The amount of reactive power that needs to be compensated:

ΔQ _reg =K _VQ *ΔU (7)

In the formula, ΔQ _reg is the amount of reactive power compensation that needs to be adjusted by the wind farm, and K _VQ is the sensitivity coefficient of voltage-reactive power at the grid-connected point, which is adjusted according to the actual situation on site.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention, in the step (5), the reactive power generated by the uncontrollable wind turbine determined in the step (3) is The total amount of reactive power Q _wnc and the reactive power compensation amount ΔQ _reg calculated in the step (4), and determine the total amount of reactive power Q _reg that needs to be adjusted by the wind farm. The power allocation strategy allocates the total amount of reactive power Q _reg that needs to be adjusted by the wind farm;

Q _reg =Q _meas +ΔQ _reg -Q _wnc (8)

If Q _wc ^min < Q _reg < Q _wc ^max , then adjust the reactive power reference of the fan according to the fan adjustment sequence determined in the step (1);

When Q _reg > 0, take

n=[Q _reg /Q _wl ^max ] (9)

Among them, [] represents an integer, then adjust the reactive power setting of the first n fans as:

Q _wi ^give =Q _wl ^max (i=1…n) (10)

The reactive power setting of the n+1 fan is:

Q _wi ^give =Q _reg –n*Q _wl ^max (i=n+1) (11)

The reactive power setting of the remaining fans and SVC is 0;

When Q _reg <0, take

n=[Q _reg /Q _wl ^min ] (12)

Then adjust the reactive power setting of the first n fans as:

Q _wi ^give =Q _wl ^min (i=1…n) (13)

The reactive power setting of the n+1 fan is:

Q _wi ^give =Q _reg –n*Q _wl ^min (i=n+1) (14)

The reactive power setting of the remaining fans and SVC is 0;

If Q _reg > Q _wc ^max , the reactive power setting of all controllable fans is:

Q _wi ^give =Q _wl ^max (i=1…N _c ) (15)

The reactive power setting of the centralized reactive power compensation device of the wind farm is:

Q _svc ^give =Q _reg –Q _wc ^max (16)

If Q _reg -Q _wc ^max >Q _svc ^max , then the reactive power setting of the wind farm centralized reactive power compensation device is:

Q _svc ^give =Q _svc ^max (17)

If Q _reg < Q _wc ^min , the reactive power setting of all controllable fans is:

Q _wi ^give =Q _wl ^min (i=1-N _c ) (18)

The reactive power setting of the centralized reactive power compensation device of the wind farm is:

Q _svc ^give =Q _reg –Q _wc ^min (19)

If Q _reg -Q _wc ^max <Q _svc ^min , then the reactive power setting of the wind farm centralized reactive power compensation device is:

Q _svc ^give =Q _svc ^min (20)

Among them, Q _svc ^max _is the ^upper _limit of reactive power _{of SVC, Q svc} ^min _is ^the lower limit of reactive power ^of _SVC ^; The power compensation device is determined.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention is to receive the reactive power setting value issued by the automatic voltage control system and at the same time receive the The issued target voltage U _ref of the grid-connected point of the wind farm is compared with the real-time voltage U _meas of the grid-connected point of the wind farm to obtain the voltage deviation value,

ΔU ₁ =|U _ref -U _meas | (21)

Setting the voltage regulation dead zone U _dead2 of the centralized reactive power compensation device of the wind farm, if the voltage deviation value ΔU ₁ < U _dead2 , then the reactive power reference setting of the centralized reactive power compensation device of the wind farm is:

Q _svc ^ref =Q _svc ^give (22)

If the voltage deviation value ΔU ₁ >U _dead2 , then the reactive power reference setting of the centralized reactive power compensation device of the wind farm is:

Q _svc ^ref =(K _p +K _i /s)*(ΔU ₁ -K _r *ΔQ)+Q _svc ^give (23)

Among them, K _p is the proportional coefficient of PI regulator; K _i is the integral coefficient of PI regulator; K _r is the adjustment coefficient; ΔQ is the real-time reactive power adjustment value of SVC.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention, the per unit value of the dead zone U _dead1 of the voltage deviation value is taken as 0.01, or according to the actual requirements of the site Flexible adjustment.

Another preferred control method of the reactive power control system applicable to the voltage control of the grid-connected point of the wind farm provided by the present invention, the per-unit value of the voltage regulation dead zone U _dead2 is taken as 0.003, or it can be flexibly adjusted according to the actual situation on site adjust.

Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects

1. In the technical solution of the present invention, two dead zones for voltage regulation are respectively set in the AVC system and the SVC control system, so as to give full play to the rapid regulation performance of reactive power and voltage of the SVC and the overall situation of the AVC system for the fan and SVC in the wind farm. coordination performance;

2. In the technical solution of the present invention, when the grid-connected point voltage deviation exceeds U _dead2 but not beyond U _dead1 , the SVC starts to adjust to reduce the fluctuation range of the grid-connected point voltage, thereby reducing the probability that the grid-connected point voltage deviation exceeds U _dead1 , and avoids triggering The AVC system is adjusted to reduce the number of reactive power adjustment actions of the wind turbine, which is conducive to the stable operation of the wind turbine;

3. In the technical solution of the present invention, when the grid-connected point voltage deviation exceeds U _dead1 , the AVC system starts to adjust, fully utilizes the reactive power adjustment capability of the wind turbine, and gives priority to the reactive power distribution of the wind turbine. When the reactive power capacity of the wind turbine is insufficient , and then distribute reactive power to SVC, leaving as much adjustment margin as possible for SVC for real-time adjustment;

4. In the technical solution of the present invention, when reactive power is distributed to the wind turbines, the adjustment order of the wind turbines is selected according to the sensitivity of the reactive power adjustment of the wind turbines to the voltage of the grid-connected point of the wind farm, which can enhance the adjustment effect and reduce the number of adjustments , can also reduce the line loss in the wind farm;

5. In the technical solution of the present invention, the SVC can directly adjust the voltage of the grid-connected point measured by the measuring element, has a fast response speed, and can perform real-time adjustment to the voltage fluctuation of the wind farm grid-connected point. Compared with the previous wind farm reactive power control The system is more real-time. the

6. The technical solution of the present invention plays a key supporting role for the wind farm to better participate in the dispatching operation of the power system. the

Description of drawings

Fig. 1 is a schematic structural diagram of the system of the present invention;

Fig. 2 is the schematic diagram of SVC control principle in the present invention

Fig. 3 is a flow chart of the method of the present invention. the

Detailed ways

Below in conjunction with embodiment the invention is described in further detail. the

Example 1:

As shown in Figure 1, the invention of this example is applicable to the reactive power control system of the grid-connected point voltage control of the wind farm. The system includes a dispatching system, and the dispatching system is connected to the automatic voltage control (AVC) system of the wind farm. The automatic voltage control system is respectively connected to the reactive power reference given by the improved centralized reactive power compensation device (SVC) of the wind farm, the measuring device and the fan data acquisition and monitoring control (SCADA) system; the fan data acquisition and monitoring control (SCADA) The system is connected with the wind turbines with reactive power adjustment capability in the wind farm. The AVC system of the wind farm communicates with the dispatching system, the measuring device, the wind turbine SCADA system, and the centralized reactive power compensation device (SVC) of the wind farm and sends out instructions. At the same time, the centralized reactive power compensation device (SVC) of the wind farm also receives The dispatching instructions of the dispatching system and the information collected by the measuring device are controlled in real time. the

The automatic voltage control system of the wind farm interacts with the dispatching system with the voltage dispatching instruction information issued by the dispatching system, and the grid-connected point voltage, Reactive power of the grid-connected point and reactive power of each fan;

The interaction between the automatic voltage control system of the wind farm and the measuring device includes the information of the grid connection point voltage and reactive power of the wind farm sent by the measuring device to the automatic voltage control system of the wind farm;

The interaction between the wind farm automatic voltage control system and the wind turbine data acquisition and monitoring control system includes the reactive power control instructions sent by the wind farm automatic voltage control system to the wind turbine data acquisition and monitoring control system for each controllable wind turbine, The fan data acquisition and monitoring control system sends information on the operating status and reactive power of each fan to the automatic voltage control system of the wind farm;

The interaction between the automatic voltage control system of the wind farm and the centralized reactive power compensation device of the wind farm includes the reactive power control command sent by the automatic voltage control system of the wind farm to the centralized reactive power compensation device of the wind farm, and the centralized reactive power compensation device of the wind farm. The compensation device sends information about its operating status and reactive power to the automatic voltage control system of the wind farm;

The interaction between the measurement device and the centralized reactive power compensation device of the wind farm includes the information of the grid connection point voltage of the wind farm sent by the measurement device to the centralized reactive power compensation device of the wind farm. the

As shown in Figure 2, the improved SVC control schematic diagram; among them, U _ref is the target voltage value of the grid-connected point issued by the dispatching system; U _meas is the measured value of the grid-connected point voltage; U _dead2 is the voltage regulation dead-end of the SVC controller σ _max is the upper limit of SVC reactive power increase regulation speed; σ _min is the lower limit of SVC reactive power reduction regulation speed; K _p is the proportional coefficient of PI regulator; K _i is the integral coefficient of PI regulator; K _r is the adjustment coefficient ; ΔQ is the real-time reactive power adjustment value of SVC; Q _svc ^give is the reactive power setting value issued by the AVC system to SVC; Q _max is the upper limit of reactive power regulation of SVC; Q _min is the lower limit of reactive power regulation of SVC; Q _ref is Reactive reference value of SVC;

The working process of SVC control system to obtain reactive power reference is:

The SVC controller receives the target voltage U _ref of the grid-connected point of the wind farm issued by the dispatching system and the real-time voltage U _meas of the grid-connected point of the wind farm, and compares them to obtain the voltage deviation ΔU. If ΔU is within the dead zone range U _dead2 , the SVC The real-time reactive power adjustment value of the SVC remains _unchanged , and the reactive power reference setting of the SVC will not change; If the voltage deviation is small, the real-time reactive power regulation of SVC will be smaller, and then the reactive power reference setting of SVC will also be reduced.

As shown in Figure 3, the control flow chart of the AVC system; if the real-time adjustment of the SVC still cannot control the voltage deviation, so that ΔU exceeds the dead zone range U _dead1 , the AVC system starts to adjust, and the specific steps are:

Step 1: According to the order of the reactive power output of each fan in the wind farm to the voltage sensitivity of the grid-connected point of the wind farm, determine the order in which the AVC system of the wind farm adjusts the reactive output of the fan. The specific method for determining the sensitivity is:

Referring to the P-Q decomposition method in power flow calculation, in the P-Q decomposition method,

ΔQ=-B*ΔV (1)

Among them, B is the imaginary part of the admittance matrix of the grid-connected point of the wind farm and each fan node. ΔQ is the reactive power variation of the corresponding node, and ΔV is the voltage variation of the corresponding node. Change the above formula to get

ΔV=-B ^-1 *ΔQ (2)

It is only necessary to obtain the values of each column of each wind turbine node in the row corresponding to the busbar of the grid-connected point in -B ^-1 , and compare the value, and the wind turbine at the node with a large corresponding value is prioritized for reactive power adjustment.

Step 2: Determine whether the reactive power of each fan is controllable, if it is controllable, set the reactive power control flag C _flag of the corresponding fan =1, if it is not controllable, set the reactive power control flag C _flag of the corresponding fan =0 . When the following situation occurs, that is, it is judged that the fan is uncontrollable, set C _flag =0, otherwise set C _flag =1.

① The fan itself sends out a fault alarm;

② The communication between the fan and the fan SCADA system is interrupted;

③ The fan cannot be controlled according to the reactive power command issued by the AVC system. the

Step 3: According to the reactive power controllable state of each fan determined in step 2, determine the total number of reactive power controllable fans _Nc of the entire wind farm, and then determine the upper and lower limits of the total adjustable reactive power of the fans in the wind farm,

The upper limit of the total reactive power of the fans in the wind farm Q _wc ^max =N _c *Q _wl ^max (3)

The lower limit of the adjustable total reactive power of the fans in the wind farm Q _wc ^min =N _c *Q _wl ^min (4)

In the formula, Q _wl ^min is the lower limit of reactive power of the fan, and Q _wl ^max is the upper limit of reactive power of the fan. Then calculate the total amount of reactive power emitted by the reactive uncontrollable fan,

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; wnc</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Sigma;Q</span>}}_{\mathrm{<span\; class="notranslate">\; meas</span>}}^{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

为无功控制标志位C_flag=0的风机的当前无功。  In the formula,

It is the current reactive power of the fan whose reactive power control flag bit C _flag =0.

Step 4: Compare the target voltage U _ref of the grid-connected point of the wind farm issued by the dispatching system with the real-time voltage U _meas of the grid-connected point of the wind farm to obtain the voltage deviation value,

ΔU=|U _ref -U _meas | (6)

A dead zone U _dead1 needs to be set for the voltage deviation value, so as to prevent the AVC system from frequently adjusting the equipment. If the voltage deviation value ΔU<U _dead1 , the AVC system _will no longer re-adjust the reactive power reference of the wind turbines and SVC in the wind farm. The power reference is rescaled.

Step 5: If the voltage deviation value ΔU>U _dead1 , calculate the amount of reactive power that needs to be compensated by the wind farm through the relationship between voltage and reactive power,

ΔQ _reg =K _VQ *ΔU (7)

In the formula, ΔQ _reg is the amount of reactive power compensation that needs to be adjusted by the wind farm, and K _VQ is the sensitivity coefficient of voltage-reactive power at the grid-connected point, which is adjusted according to the actual situation on site.

Step 6: Using the total amount of reactive power Q _wnc from the reactive uncontrollable fan calculated in step 3 and the amount of reactive power compensation ΔQ _reg calculated in step 5, calculate the total amount of reactive power Q _reg that needs to be adjusted by the wind farm, according to The reactive power allocation strategy of the fan first and then the SVC allocates Q _reg ,

Q _reg =Q _meas +ΔQ _reg -Q _wnc (8)

If Q _wc ^min < Q _reg < Q _wc ^max , then adjust the reactive power reference of the fan according to the fan adjustment sequence determined in step 1. When Q _reg > 0, take

n=[Q _reg /Q _wl ^max ] (9)

Among them, [] represents an integer, then adjust the reactive power setting of the first n fans as:

Q _wi ^give =Q _wl ^max (i=1…n) (10)

The reactive power setting of the n+1 fan is:

Q _wi ^give =Q _reg –n*Q _wl ^max (i=n+1) (11)

The reactive power of the remaining fans and SVC is set to 0. the

When Q _reg <0, take

n=[Q _reg /Q _wl ^min ] (12)

Then adjust the reactive power setting of the first n fans as:

Q _wi ^give =Q _wl ^min (i=1…n) (13)

The reactive power setting of the n+1 fan is:

Q _wi ^give =Q _reg –n*Q _wl ^min (i=n+1) (14)

The reactive power of the remaining fans and SVC is set to 0. the

If Q _reg > Q _wc ^max , the reactive power setting of all controllable fans is:

Q _wi ^give =Q _wl ^max (i=1…N _c ) (15)

The reactive power setting of SVC is:

Q _svc ^give =Q _reg –Q _wc ^max (16)

If Q _reg –Q _wc ^max >Q _svc ^max , then the reactive power setting of SVC is:

Q _svc ^give =Q _svc ^max (17)

If Q _reg < Q _wc ^min , the reactive power setting of all controllable fans is:

Q _wi ^give =Q _wl ^min (i=1-N _c ) (18)

The reactive power setting of SVC is:

Q _svc ^give =Q _reg –Q _wc ^min (19)

If Q _reg –Q _wc ^max <Q _svc ^min , then the reactive power setting of SVC is:

Q _svc ^give =Q _svc ^min (20)

Among them, Q _svc ^max is the upper limit of reactive power of SVC, and Q _svc ^min is the lower limit of reactive power of SVC. Q _wl ^min , Q _wl ^max , Q _svc ^min and Q _svc ^max are determined according to the fans and SVC devices actually running on site.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be implemented Modifications or equivalent replacements are made to the specific embodiments, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the present claims. the

Claims (12)

1. one kind is applicable to the powerless control system that wind farm grid-connected point voltage is controlled, described system comprises dispatching patcher, it is characterized in that: described dispatching patcher connects wind energy turbine set automatic voltage control system, described wind energy turbine set automatic voltage control system connects respectively wind energy turbine set and concentrates reactive power compensator, measurement mechanism and blower fan data acquisition and supervisor control; Described blower fan data acquisition is connected with the blower fan in wind energy turbine set with idle regulating power with supervisor control.

2. a kind of powerless control system that wind farm grid-connected point voltage is controlled that is applicable to as claimed in claim 1, it is characterized in that: the voltage communication with dispatch instructions that the mutual described dispatching patcher of described wind energy turbine set automatic voltage control system and described dispatching patcher issues, needs described wind energy turbine set automatic voltage control system to send to the wind farm grid-connected point voltage of described dispatching patcher site reactive power and each blower fan reactive power information according to scheduling;

Described wind energy turbine set automatic voltage control system and described measurement mechanism comprise that described measurement mechanism sends to the wind farm grid-connected point voltage of described wind energy turbine set automatic voltage control system and the information of reactive power alternately;

Described wind energy turbine set automatic voltage control system and described blower fan data acquisition and supervisor control comprise that described wind energy turbine set automatic voltage control system sends to the idle control command of described blower fan data acquisition and each controlled blower fan of supervisor control, described blower fan data acquisition and supervisor control to send to the running status of described wind energy turbine set automatic voltage control system wind turbine and the information of reactive power alternately;

Described wind energy turbine set automatic voltage control system and described wind energy turbine set concentrate reactive power compensator to comprise that alternately wind energy turbine set automatic voltage control system sends to wind energy turbine set to concentrate the idle control command of described reactive power compensator, described wind energy turbine set to concentrate reactive power compensator to send to the information of its running status of wind energy turbine set automatic voltage control system and reactive power;

Described measurement mechanism and described wind energy turbine set concentrate reactive power compensator to comprise that alternately measurement mechanism sends to described wind energy turbine set to concentrate the information of the wind farm grid-connected point voltage of reactive power compensator.

3. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 1 or 2, is characterized in that: said method comprising the steps of:

(1) according to the idle sequence of size to wind farm grid-connected point voltage sensitivity of exerting oneself of wind turbine in wind energy turbine set, described wind energy turbine set automatic voltage control system regulates idle the exerting oneself of blower fan according to the descending order of sensitivity;

(2) determine the idle whether controlled of described wind turbine;

(3), according to the idle controllable state of the described definite wind turbine of described step (2), determine the idle controlled blower fan sum N of whole wind energy turbine set _c, and then the bound of the adjustable idle total amount of definite wind energy turbine set inner blower;

(4) the wind farm grid-connected point target voltage U described dispatching patcher being issued _refreal-time voltage U with wind farm grid-connected point _meascompare, obtain voltage deviation value;

(5) determine the idle total amount Q that wind energy turbine set need to regulate _reg, according to the idle total amount Q that after first described blower fan, wind energy turbine set concentrates the idle allocation strategy of reactive power compensator need to regulate wind energy turbine set _regdistribute.

4. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 3, is characterized in that: the process of determining described level of sensitivity is:

P-Q decomposition method in calculating according to trend, in P-Q decomposition method,

ΔQ=-B*ΔV (1)

Wherein, B is the imaginary part of wind farm grid-connected point and wind turbine node admittance matrix, the reactive power variable quantity that Δ Q is corresponding node, and the voltage variety that Δ V is corresponding node, changes above formula, obtains

ΔV=-B ^-1*ΔQ (2)

By determine-B ^-1in with and row corresponding to site bus in respect to each columns value of each blower fan node, the size of numerical value relatively, the node blower fan that corresponding numerical value is large preferentially carries out idle adjusting.

5. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 4, is characterized in that: described step (2) if in the idle controlled idle control flag bit C that puts corresponding blower fan of described wind turbine _flag=1; If described wind turbine is idle uncontrollable, put the idle control flag bit C of corresponding blower fan _flag=0; There is following situation, judge that blower fan is uncontrollable, put C _flag=0, otherwise put C _flag=1;

Described blower fan itself sends fault alarm; Or

The communicating interrupt of described blower fan and blower fan data acquisition and supervisor control; Or

The idle instruction that described blower fan can not issue according to automatic voltage control system is controlled.

6. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 5, is characterized in that: the bound process of determining the adjustable idle total amount of wind energy turbine set inner blower in described step 3 is:

The upper limit Q of the adjustable idle total amount of wind energy turbine set inner blower _wc ^max=N _c* Q _wl ^max(3)

The lower limit Q of the adjustable idle total amount of wind energy turbine set inner blower _wc ^min=N _c* Q _wl ^min(4)

In formula, Q _wl ^minfor the idle lower limit of blower fan, Q _wl ^maxthe idle upper limit for blower fan; Calculate again the idle total amount that idle uncontrollable blower fan sends:

In formula,

for idle control flag bit C _flag=0 blower fan current idle.

7. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 6, is characterized in that: in described step (4), voltage deviation value is:

ΔU=|U _ref-U _meas| (6)

Voltage deviation value is set to dead band U _dead1thereby, avoid described wind energy turbine set automatic voltage control system frequently equipment to be regulated; If voltage deviation value Δ U < is U _dead1, described wind energy turbine set automatic voltage control system no longer concentrates the idle reference of reactive power compensator again to adjust to the described blower fan in wind energy turbine set and wind energy turbine set; If voltage deviation value Δ U > is U _dead1, described wind energy turbine set automatic voltage control system concentrates the idle reference of reactive power compensator again to adjust to the blower fan in described wind energy turbine set and wind energy turbine set.

8. a kind of control method that is applicable to the powerless control system of wind farm grid-connected point voltage control as claimed in claim 7, is characterized in that: as described voltage deviation value Δ U > U _dead1, by voltage and idle relation, calculate the reactive power amount that wind energy turbine set need to compensate:

ΔQ _reg=K _V-Q*ΔU (7)

In formula, Δ Q _regfor the reactive power compensation amount that wind energy turbine set need to regulate, K _v-Qfor grid-connected point voltage-idle sensitivity coefficient, according to on-site actual situations, adjust.

9. a kind of control method that is applicable to the powerless control system of wind farm grid-connected point voltage control as claimed in claim 8, is characterized in that: the idle total amount Q that the idle uncontrollable blower fan that described step (5) is determined by described step (3) sends _wncthe reactive power compensation amount Δ Q calculating with described step (4) _reg, and definite wind energy turbine set idle total amount Q that need to regulate _reg, the idle total amount Q that concentrates the idle allocation strategy of reactive power compensator need to regulate wind energy turbine set according to wind energy turbine set after first blower fan _regdistribute;

Q _reg=Q _meas+ΔQ _reg-Q _wnc (8)

If Q _wc ^min< Q _reg< Q _wc ^max, according to the definite blower fan adjustment order of described step (1), the idle reference of blower fan is adjusted;

Work as Q _reg> 0, gets

n=[Q _reg/Q _wl ^max] (9)

Wherein, [] represents round numbers, before adjusting n Fans idle adjust into:

Q _wi ^give=Q _wl ^max(i=1…n) (10)

N+1 Fans idle adjust into:

Q _wi ^give=Q _reg–n*Q _wl ^max(i=n+1) (11)

Idle the adjusting of remaining blower fan and SVC is 0;

Work as Q _reg< 0, gets

n=[Q _reg/Q _wl ^min] (12)

Before adjusting n Fans idle adjust into:

Q _wi ^give=Q _wl ^min(i=1…n) (13)

N+1 Fans idle adjust into,

Q _wi ^give=Q _reg–n*Q _wl ^min(i=n+1) (14)

Idle the adjusting of remaining blower fan and SVC is 0;

If Q _reg> Q _wc ^max, all controlled blower fans idle adjust into:

Q _wi ^give=Q _wl ^max(i=1…N _c) (15)

Described wind energy turbine set is concentrated reactive power compensator idle adjust into:

Q _svc ^give=Q _reg–Q _wc ^max (16)

If Q _reg– Q _wc ^max> Q _svc ^max, described wind energy turbine set is concentrated reactive power compensator idle adjust into:

Q _svc ^give=Q _svc ^max (17)

If Q _reg< Q _wc ^min, all controlled blower fans idle adjust into:

Q _wi ^give=Q _wl ^min(i=1-N _c) (18)

Described wind energy turbine set is concentrated reactive power compensator idle adjust into:

Q _svc ^give=Q _reg–Q _wc ^min (19)

If Q _reg– Q _wc ^max< Q _svc ^min, described wind energy turbine set is concentrated reactive power compensator idle adjust into:

Q _svc ^give=Q _svc ^min (20)

Wherein, Q _svc ^maxfor the idle upper limit of SVC, Q _svc ^minidle lower limit for SVC; Q _wl ^min, Q _wl ^max, Q _svc ^minand Q _svc ^maxaccording to the blower fan of on-the-spot actual motion and described wind energy turbine set, concentrate reactive power compensator to determine.

10. a kind of control method that is applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 9, it is characterized in that: in the idle setting value issuing at the described automatic voltage control system of reception, receive the wind farm grid-connected point target voltage U that described dispatching patcher issues _refreal-time voltage U with wind farm grid-connected point _meas, and compare, obtain voltage deviation value,

ΔU ₁=|U _ref-U _meas| (21)

Set described wind energy turbine set and concentrate the voltage-regulation dead band U of reactive power compensator _dead2if, voltage deviation value Δ U ₁< U _dead2, described wind energy turbine set concentrates the idle reference of reactive power compensator to be given as:

Q _svc ^ref=Q _svc ^give (22)

If voltage deviation value Δ U ₁> U _dead2, described wind energy turbine set concentrates the idle reference of reactive power compensator to be given as:

Q _svc ^ref=(K _p+K _i/s)*(ΔU ₁-K _r*ΔQ)+Q _svc ^give (23)

Wherein, K _pproportionality coefficient for pi regulator; K _iintegral coefficient for pi regulator; K _rfor difference coefficient; Δ Q is the real-time idle regulated quantity of SVC.

11. a kind of control methods that are applicable to the powerless control system that wind farm grid-connected point voltage controls as claimed in claim 7 or 8, is characterized in that: described voltage deviation value dead band U _dead1perunit value be taken as 0.01, or carry out flexible according to on-the-spot actual requirement.

12. a kind of control methods that are applicable to the powerless control system of wind farm grid-connected point voltage control as claimed in claim 10, is characterized in that: described voltage-regulation dead band U _dead2perunit value be taken as 0.003, or carry out flexible according to on-site actual situations.

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