CN104201700B - Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation - Google Patents
Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation Download PDFInfo
- Publication number
- CN104201700B CN104201700B CN201410486165.4A CN201410486165A CN104201700B CN 104201700 B CN104201700 B CN 104201700B CN 201410486165 A CN201410486165 A CN 201410486165A CN 104201700 B CN104201700 B CN 104201700B
- Authority
- CN
- China
- Prior art keywords
- power
- wind power
- frequency
- fluctuation
- level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 54
- 230000005611 electricity Effects 0.000 title 1
- 230000005619 thermoelectricity Effects 0.000 title 1
- 230000014509 gene expression Effects 0.000 claims abstract description 48
- 238000004458 analytical method Methods 0.000 claims abstract description 23
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 19
- 238000004364 calculation method Methods 0.000 claims abstract description 13
- 238000004445 quantitative analysis Methods 0.000 claims abstract description 12
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 11
- 238000005070 sampling Methods 0.000 claims description 38
- 230000003595 spectral effect Effects 0.000 claims description 32
- 238000009795 derivation Methods 0.000 claims description 11
- 230000001360 synchronised effect Effects 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 238000010248 power generation Methods 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004088 simulation Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 238000007430 reference method Methods 0.000 description 1
Landscapes
- Wind Motors (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
计及风电不确定性波动的区域电网火电调频机组配置方法,涉及一种考虑风电的火电调频机组配置方法。为了解决大规模风电并网后对系统频率稳定造成影响的问题。本发明以Mallat小波分解和重构算法为工具,进行风功率时间序列的分解和重构,基于小波多尺度的分析方法,建立秒级、分钟级风电厂功率不确定性波动的瞬时模型,给出时域瞬时表达式后,建立用于调频分析的含风电区域电网模型,基于调频分析模型,给出表征系统一、二次调频能力的表达式,基于调频能力表达式,定量分析计算系统在不同条件下的一、二次调频能力。本发明可以减小风功率波动造成的系统频率波动,维持系统频率稳定。本发明适用于考虑风电的火电调频机组配置。
A configuration method for thermal power frequency modulation units in a regional power grid considering wind power uncertainty fluctuations relates to a configuration method for thermal power frequency modulation units considering wind power. In order to solve the problem of affecting the system frequency stability after large-scale wind power is connected to the grid. The present invention uses the Mallat wavelet decomposition and reconstruction algorithm as a tool to decompose and reconstruct the wind power time series, and based on the wavelet multi-scale analysis method, establishes the instantaneous model of the second-level and minute-level wind power uncertainty fluctuations, giving After the time-domain instantaneous expression is obtained, a regional power grid model including wind power for frequency modulation analysis is established. Based on the frequency modulation analysis model, expressions representing the primary and secondary frequency modulation capabilities of the system are given. Based on the frequency modulation capability expressions, the quantitative analysis calculation system is Primary and secondary frequency modulation capabilities under different conditions. The invention can reduce system frequency fluctuations caused by wind power fluctuations and maintain system frequency stability. The invention is applicable to the configuration of thermal power frequency modulation units considering wind power.
Description
技术领域technical field
本发明涉及一种考虑风电的火电调频机组配置方法The invention relates to a configuration method of a thermal power frequency regulation unit considering wind power
背景技术Background technique
现有风电超短期预报技术一般仅给出风功率在某一时刻点的具体值,时间分辨率为15分钟,无法对更小时间分辨率下的风电不确定性波动进行预报;而且现有模型考虑风电机组的调频问题时,一般未将有功功率和无功功率解耦,而是笼统的考虑,不利于有效的分析;在分析风电波动对系统调频的影响时,没有将不同时间尺度下的风功率波动同一、二次调频的时间尺度相对应来分析,不利于有针对性的分析;并且现有电力系统调频机组配置方法,因风电接入率较小,仅根据负荷的波动程度来配置机组,不利于风电大规模并网后的系统频率稳定。The existing wind power ultra-short-term forecasting technology generally only gives the specific value of wind power at a certain point in time, and the time resolution is 15 minutes, which cannot predict the uncertainty fluctuation of wind power at a smaller time resolution; and the existing model When considering the frequency modulation of wind turbines, active power and reactive power are generally not decoupled, but generally considered, which is not conducive to effective analysis; when analyzing the impact of wind power fluctuations on system frequency modulation, they do not take into account The analysis of the same wind power fluctuation and the corresponding time scale of the secondary frequency regulation is not conducive to targeted analysis; and the existing power system frequency regulation unit configuration method is only configured according to the degree of load fluctuation due to the small wind power access rate Units are not conducive to the stability of the system frequency after large-scale grid-connected wind power.
发明内容Contents of the invention
本发明为了解决大规模风电并网后对系统频率稳定造成影响的问题,进而提出了一种计及风电不确定性波动的区域电网火电调频机组配置方法。In order to solve the problem of influence on system frequency stability after large-scale wind power is connected to the grid, the present invention further proposes a regional power grid thermal power frequency regulation unit configuration method that takes into account wind power uncertainty fluctuations.
计及风电不确定性波动的区域电网火电调频机组配置方法的过程为:The process of the configuration method of thermal power frequency modulation units in the regional power grid considering the uncertainty fluctuation of wind power is as follows:
步骤一:以Mallat小波分解和重构算法为工具,并选择db10作为小波基,进行风功率时间序列的分解和重构:首先,对采样间隔为nS的实测风功率数据进行小波分解,具体分解层数m由采样间隔决定,应保证分解的最后一层周期n·2m恰好为15min或者n·2m大于15min并且最接近15min,若n·2m与15min的差在3min内,则将第m层作为小时级别的小时平均风功率,若n·2m与15min的差大于3min,则将第m层与第m-1层进行重构,得到周期为小时级别的小时平均风功率;将后面的周期为秒级以及分钟级的分解层分别进行重构,得到原始风功率序列去掉小时平均风功率后的秒级、分钟级功率波动残差;Step 1: Use the Mallat wavelet decomposition and reconstruction algorithm as a tool, and select db10 as the wavelet base to decompose and reconstruct the wind power time series: first, perform wavelet decomposition on the measured wind power data with a sampling interval of nS, and specifically decompose The number of layers m is determined by the sampling interval. It should be ensured that the last layer period of decomposition n·2 m is exactly 15 min or n·2 m is greater than 15 min and the closest to 15 min. If the difference between n·2 m and 15 min is within 3 min, the The m-th layer is used as the hourly average wind power at the hourly level. If the difference between n·2 m and 15 min is greater than 3 min, the m-th layer and the m-1th layer are reconstructed to obtain the hourly average wind power at the hourly level; Reconstruct the second-level and minute-level decomposition layers of the subsequent periods to obtain the second-level and minute-level power fluctuation residuals after the hourly average wind power is removed from the original wind power sequence;
基于小波多尺度的分析方法,建立秒级、分钟级风电厂功率不确定性波动的瞬时模型,给出时域瞬时表达式;Based on the wavelet multi-scale analysis method, the instantaneous model of the second-level and minute-level wind power uncertainty fluctuations is established, and the time-domain instantaneous expression is given;
(1)分级风功率波动同风电场小时级平均功率的瞬时关系表达式(1) Instantaneous relationship expression between graded wind power fluctuation and hourly average power of wind farm
式中,σm为风电场输出功率分钟级波动的标准差,为风电场小时级平均功率,a、b、c为拟合系数,可通过最小二乘法拟合确定;In the formula, σm is the standard deviation of the minute-level fluctuation of the output power of the wind farm, is the hourly average power of the wind farm, a, b, and c are the fitting coefficients, which can be determined by least square fitting;
(2)秒级风功率波动同风电场小时级平均功率的瞬时关系表达式(2) Instantaneous relationship expression between the second-level wind power fluctuation and the hour-level average power of the wind farm
式中,σs为风电场输出功率秒级波动的标准差;In the formula, σ s is the standard deviation of the second-level fluctuation of the output power of the wind farm;
式(1)、(2)建立了秒级、分钟级风电厂功率不确定性波动的标准差同风电场小时级平均功率间的实时对应关系;时间分辨率为15分钟的风功率预测值恰好为小时级风功率,将其作为式(1)、(2)中的进行输入,对秒级、分钟级风电厂功率不确定性波动的范围进行实时预报;Formulas (1) and (2) establish the real-time correspondence between the standard deviation of the second-level and minute-level wind power uncertainty fluctuations and the hourly average power of the wind farm; the wind power prediction value with a time resolution of 15 minutes is exactly is the hour-level wind power, which is used as the formula (1) and (2) Input, real-time forecast for the range of second-level and minute-level wind power plant power uncertainty fluctuations;
步骤二:根据电厂的实际情况,建立用于调频分析的含风电区域电网模型,基于调频分析模型,给出表征系统一、二次调频能力的表达式:Step 2: According to the actual situation of the power plant, establish a regional power grid model including wind power for frequency regulation analysis, and based on the frequency regulation analysis model, give the expressions representing the primary and secondary frequency regulation capabilities of the system:
建立用于调频分析的含风电的区域电网模型,如图2所示;其中区域A中含有风电,区域B中只包含火电机组;Establish a regional power grid model with wind power for frequency modulation analysis, as shown in Figure 2; where area A contains wind power, and area B only includes thermal power units;
每个区域中分别含有一次调频通道以及二次调频通道,系统的输出为当前各区域的频率偏差χf(s),各区域的频率偏差χf(s)作为反馈信号通过一、二次调频通道实现对各自区域频率的一、二次调节;图中,αi为第i台机组的发电份额系数,δi为第i台火电机组的调差系数,Ri为参加二次调频机组的功率分配系数,BA、BB为各区域的频率偏差系数,KA、KB分别为各区域二次调频积分器增益;Gi(s)为第i台发电机组的传递函数,具体表达式如下:Each area contains a primary frequency modulation channel and a secondary frequency modulation channel. The output of the system is the current frequency deviation χ f (s) of each area, and the frequency deviation χ f (s) of each area is used as a feedback signal through the primary and secondary frequency modulation The channel realizes the primary and secondary adjustment of the frequency in each area; in the figure, α i is the power generation share coefficient of the i-th unit, δ i is the adjustment coefficient of the i-th thermal power unit, and R i is the frequency of the unit participating in the secondary frequency regulation. Power distribution coefficient, B A , B B are the frequency deviation coefficients of each area, K A , K B are the gains of the secondary frequency modulation integrator in each area respectively; G i (s) is the transfer function of the i-th generator set, specifically expressed as The formula is as follows:
其中,表示液压伺服电机的动态特性,Tss是液压伺服电机时间常数,取Tss=0.2s;表示汽轮机的容积动态特性,T0s是高压缸的容积时间常数;Ta∑表示等效转子时间常数,本系统中除风机外均为同步发电机,将所有同步发电机等效为一台同步发电机,再用功率份额系数乘以各自的转子时间常数,即可求出等效转子时间常数;βA、βB分别表示区域A和区域B的等效摩擦系数,与Ta∑的求取方法是一样的,也是根据功率份额系数来求取;负荷的波动、风功率的波动以及联络线功率的波动分别为χNL(s)、χWind(s)以及χPtie(s);in, Indicates the dynamic characteristics of the hydraulic servo motor, T s s is the time constant of the hydraulic servo motor, take T s s = 0.2s; Indicates the dynamic characteristics of the volume of the steam turbine, T 0 s is the volume time constant of the high-pressure cylinder; T a∑ indicates the equivalent rotor time constant, and all synchronous generators in this system except the fan are equivalent to one For a synchronous generator, the equivalent rotor time constant can be obtained by multiplying the power share coefficient by the respective rotor time constant; β A and β B represent the equivalent friction coefficients of area A and area B respectively , and the The calculation method is the same, and it is also calculated according to the power share coefficient; the load fluctuation, wind power fluctuation and tie line power fluctuation are respectively χ NL (s), χ Wind (s) and χ Ptie (s);
考虑风功率不确定性波动的电网一次调频能力,即仅在一次调频作用下,某段时间内秒级风功率波动方差与电网频率波动方差的比值,表达式为:The primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the second-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time under the action of only one frequency regulation, the expression is:
选取图2所示模型假定区域A负荷无波动,断开其二次调频通道即只考虑一次调频作用,可以计算得出电网频率变化与秒级风功率波动的频域解析表达式为:Select the model shown in Figure 2 assuming that there is no load fluctuation in area A, disconnect its secondary frequency modulation channel, that is, only consider the primary frequency modulation effect, and calculate the frequency domain analytical expression of the grid frequency change and second-level wind power fluctuation as follows:
其中, in,
设输入为零均值信号x(t),经其对应的输入-输出传递函数H(jω)作用后,得到输出为y(t),j为虚数,ω为角频率,则输出y(t)的方差为:Suppose the input is a zero-mean signal x(t), after the corresponding input-output transfer function H(jω), the output is y(t), j is an imaginary number, and ω is the angular frequency, then the output y(t) The variance of is:
式中Sy(ω)=Sx(ω)|H(jω)|2,Sy(ω)表示输出的功率谱密度,Sx(ω)表示输入的功率谱密度;In the formula, S y (ω)=S x (ω)|H(jω)| 2 , S y (ω) represents the power spectral density of the output, and S x (ω) represents the power spectral density of the input;
考虑到所涉及的变量为偏差量,均值为0,将式(5)代入式(6)中可得由秒级风功率波动造成的系统频率波动的方差 Considering that the variables involved are deviations with an average value of 0, substituting Equation (5) into Equation (6), the variance of the system frequency fluctuation caused by the second-level wind power fluctuation can be obtained
其中,Sw1(ω)为秒级风功率波动的功率谱密度;Among them, S w1 (ω) is the power spectral density of second-level wind power fluctuations;
由PSD时频转换计算机算法可以得到,σs(i)的功率谱密度在频域中的抽样可被近似为:It can be obtained from the PSD time-frequency conversion computer algorithm, the sampling of the power spectral density of σ s (i) in the frequency domain can be approximated as:
其中,MFFT(.)为快速傅里叶变换,N为采样长度,ωs为采样频率,E(·)为均值函数;根据香浓采样定理,当采样频率高于信号频率一倍以上时,连续信号可以从采样样本中完全重建出来;因此,选择适当的采样频率,通过式(8)可得到风功率秒级波动的功率谱密度;将式(8)作为输出信号的功率谱密度带入式(6)得到秒级风功率波动的方差为:Among them, MFFT (.) is the fast Fourier transform, N is the sampling length, ω s is the sampling frequency, and E(·) is the mean function; according to the Shannon sampling theorem, when the sampling frequency is more than twice the signal frequency , the continuous signal can be completely reconstructed from the sampling samples; therefore, by selecting an appropriate sampling frequency, the power spectral density of the second-level fluctuation of wind power can be obtained through formula (8); using formula (8) as the power spectral density band of the output signal Entering formula (6), the variance of the second-level wind power fluctuation is obtained as:
经过推导可以得到考虑风功率不确定性波动的电网一次调频能力的频域解析表达式为:After derivation, the frequency-domain analytical expression of the primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power can be obtained as:
其中,为秒级风功率波动的方差,为由秒级风功率波动造成的系统频率波动的方差,Sw1(ω)为秒级风功率波动的功率谱密度;in, is the variance of the second-level wind power fluctuation, is the variance of the system frequency fluctuation caused by the second-level wind power fluctuation, S w1 (ω) is the power spectral density of the second-level wind power fluctuation;
考虑风功率不确定性波动的电网二次调频能力,即仅在二次调频作用下,某段时间内分钟级风功率波动方差与电网频率波动方差的比值,表达式为:The secondary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the minute-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time only under the secondary frequency regulation, the expression is:
采用上述推导方法,同样可以得到分钟级风功率波动的方差以及由分钟级风功率波动造成的系统频率波动的方差经过推导可以得到考虑风功率不确定性波动的电网二次调频能力的频域解析表达式为:Using the above derivation method, the variance of minute-level wind power fluctuations can also be obtained and the variance of system frequency fluctuations caused by minute-scale wind power fluctuations After derivation, the frequency-domain analytical expression of the power grid's secondary frequency regulation capability considering wind power uncertainty fluctuations can be obtained as:
其中,为分钟级风功率波动的方差,为系统频率波动的方差,Sw2(ω)为分钟级风功率波动的功率谱密度;in, is the variance of minute-level wind power fluctuations, is the variance of the system frequency fluctuation, S w2 (ω) is the power spectral density of the minute-level wind power fluctuation;
步骤三:基于调频能力表达式,定量分析计算系统在不同条件下的一、二次调频能力。Step 3: Based on the frequency modulation capability expression, quantitatively analyze and calculate the primary and secondary frequency modulation capabilities of the system under different conditions.
计及风电不确定性波动的区域电网火电调频机组配置方法的步骤三中的建立用于调频分析的含风电的区域电网模型是运用Matlab/Simulink软件实现的。The establishment of a regional power grid model including wind power for frequency modulation analysis in step three of the thermal power frequency modulation unit configuration method of regional power grid considering wind power uncertainty fluctuations is realized by using Matlab/Simulink software.
计及风电不确定性波动的区域电网火电调频机组配置方法的步骤三基于调频能力表达式定量分析计算系统在不同条件下的一、二次调频能力的实现过程为:The third step of the regional power grid thermal power frequency regulation unit configuration method considering the uncertainty fluctuation of wind power is based on the quantitative analysis of the frequency regulation capability expression and the realization process of the primary and secondary frequency regulation capabilities of the system under different conditions is as follows:
步骤1:保持火电一次调频机组比例不变,计算系统在不同调差系数下的一次调频能力;保持各机组调差系数不变,计算系统在不同火电一次调频机组比例的一次调频能力;根据计算结果,绘制以火电一次调频机组比例为横坐标,调差系数为纵坐标的表格,从表格中的数据统计出不同比例的火电一次调频机组以及不同调差系数对一次调频能力的影响规律;Step 1: Keeping the ratio of thermal power primary frequency regulation units constant, calculate the primary frequency regulation capabilities of the system under different differential coefficients; keep the differential coefficients of each unit constant, and calculate the primary frequency regulation capabilities of the system with different thermal power primary frequency regulation ratios; according to the calculation As a result, draw a table with the proportion of thermal power primary frequency modulation units as the abscissa and the adjustment coefficient as the vertical axis, and from the data in the table, the influence laws of different proportions of thermal power primary frequency modulation units and different difference adjustment coefficients on the primary frequency regulation ability are obtained;
步骤2:保持火电二次调频机组比例不变,计算系统在不同积分器增益下的二次调频能力;保持各机组积分器增益不变,计算系统在不同火电二次调频机组比例的二次调频能力;根据计算结果,绘制以火电二次调频机组比例为横坐标,积分器增益为纵坐标的表格,从表格中的数据统计出不同比例的火电二次调频机组以及不同积分器增益对二次调频能力的影响规律;Step 2: Keeping the ratio of thermal power secondary frequency modulation units constant, calculate the secondary frequency modulation capability of the system under different integrator gains; keep the integrator gains of each unit constant, and calculate the secondary frequency modulation of the system under different thermal power secondary frequency modulation unit ratios capacity; according to the calculation results, draw a table with the proportion of thermal power secondary frequency modulation units as the abscissa and the integrator gain as the vertical axis, and calculate the different ratios of thermal power secondary frequency modulation units and different integrator gains for secondary Influence law of frequency modulation capability;
步骤3:依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法。Step 3: Based on the quantitative analysis results of Step 1 and Step 2, provide a thermal power unit configuration method that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations.
计及风电不确定性波动的区域电网火电调频机组配置方法的步骤3依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法的实现过程为:Step 3 of the regional power grid thermal power frequency modulation unit configuration method considering wind power uncertainty fluctuations Based on the quantitative analysis results of steps 1 and 2, provide thermal power unit configurations that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations The implementation process of the method is:
步骤3.1.1:若A区域各机组调差系数δiA保持不变,DPFRA值为K1,K1为一个常数;当一次调频机组比例由p%增加至2p%时,DPFRA值增大至2K1;即若某一时刻风功率输出秒级波动量由P增加至k1·P,k1为一个常数,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k1·p%;Step 3.1.1: If the adjustment coefficient δ iA of each unit in area A remains unchanged, the value of D PFRA is K 1 , and K 1 is a constant; when the proportion of primary frequency adjustment units increases from p% to 2p%, the value of D PFRA increases as large as 2K 1 ; that is, if the second-level fluctuation of wind power output increases from P to k 1 ·P at a certain moment, k 1 is a constant, and the frequency is kept stable at the level when the wind power fluctuation does not increase. Increased from p% to k 1 ·p%;
步骤3.1.2:若A区域积分器增益KA不变,DSFRA值为K2,K2为假设的一个常数;当二次调频机组比例由p%增加至2p%时,DSFRA值增大至2K2;即若某一时刻风功率输出分钟级波动量由P增加至k2·P,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k2·p%。Step 3.1.2: If the gain K A of the integrator in area A remains unchanged, the value of D SFRA is K 2 , and K 2 is an assumed constant; when the proportion of the secondary frequency modulation unit increases from p% to 2p%, the value of D SFRA increases As large as 2K 2 ; that is, if the minute-level fluctuation of wind power output increases from P to k 2 ·P at a certain moment, the frequency is kept stable at the level when the wind power fluctuation does not increase, and the proportion of primary frequency modulation units is increased from p% to k 2 ·p%.
计及风电不确定性波动的区域电网火电调频机组配置方法的步骤3依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法的实现过程为:Step 3 of the regional power grid thermal power frequency modulation unit configuration method considering wind power uncertainty fluctuations Based on the quantitative analysis results of steps 1 and 2, provide thermal power unit configurations that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations The implementation process of the method is:
步骤3.2.1:若A区域中参与一次调频的机组比例保持不变,调节各机组的不等率δiA,DPFRA值与δiA间具有如下近似关系,即:Step 3.2.1: If the proportion of units participating in the primary frequency regulation in area A remains unchanged, adjust the differential rate δ iA of each unit, and the D PFRA value and δ iA have the following approximate relationship, namely:
即若某一时刻风功率输出秒级波动量由P增加至k1·P,k1为假设的一个常数,维持频率稳定在风功率波动未增加时的水平,将δiA减小至k1·δiA;That is, if the second-level fluctuation of wind power output increases from P to k 1 P at a certain moment, k 1 is a hypothetical constant, and the frequency is kept stable at the level when the wind power fluctuation does not increase, and δ iA is reduced to k 1 δ iA ;
步骤3.2.2:若A区域积分器增益KA不变,DSFRA值为K2,K2为假设的一个常数;当二次调频机组比例由p%增加至2p%时,DSFRA值增大至2K2;即若某一时刻风功率输出分钟级波动量由P增加至k2·P,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k2·p%。Step 3.2.2: If the gain K A of the integrator in area A remains unchanged, the value of D SFRA is K 2 , and K 2 is an assumed constant; when the proportion of the secondary frequency modulation unit increases from p% to 2p%, the value of D SFRA increases As large as 2K 2 ; that is, if the minute-level fluctuation of wind power output increases from P to k 2 ·P at a certain moment, the frequency is kept stable at the level when the wind power fluctuation does not increase, and the proportion of primary frequency modulation units is increased from p% to k 2 ·p%.
按本发明进行火电调频机组配置可以减小风功率波动造成的系统频率波动,维持系统频率稳定。在系统原有的火电调频机组配置情况下,在某些时间点超过系统对频率±0.1Hz的要求;当采用本发明提供的火电调频机组配置方法,系统频率波动减小,标准差由σ=0.00042885减小到σ=0.00021798。According to the configuration of thermal power frequency modulation units in the present invention, system frequency fluctuations caused by wind power fluctuations can be reduced, and the system frequency can be kept stable. In the case of the original thermal power frequency modulation unit configuration of the system, the system’s requirement for frequency ±0.1Hz is exceeded at some point in time; when the thermal power frequency modulation unit configuration method provided by the present invention is adopted, the system frequency fluctuation is reduced, and the standard deviation is changed from σ= 0.00042885 reduces to σ = 0.00021798.
附图说明Description of drawings
图1计及风电不确定性波动的区域电网火电调频机组配置方法流程示意图;Figure 1. Schematic diagram of the configuration method of thermal power frequency modulation units in regional power grids considering wind power uncertainty fluctuations;
图2用于调频分析的含风电区域电网模型;Figure 2. The regional power grid model with wind power for frequency regulation analysis;
图3采用配置方法前系统频率;Figure 3 System frequency before adopting the configuration method;
图4采用配置方法后系统频率;Figure 4 System frequency after adopting the configuration method;
图5风电场输出功率、波动分量时间序列;Figure 5. Wind farm output power and time series of fluctuation components;
图6 Mallat8层小波分解和重构算法的示意图;Fig. 6 Schematic diagram of Mallat 8-layer wavelet decomposition and reconstruction algorithm;
图7分钟级风电厂功率不确定性波动的瞬时拟合模型;Figure 7. Instantaneous fitting model of minute-level wind power plant power uncertainty fluctuations;
图8秒级风电厂功率不确定性波动的瞬时拟合模型。Figure 8. Instantaneous fitting model of second-level wind power plant power uncertainty fluctuations.
具体实施方式detailed description
具体实施方式一:结合图1和图2说明本实施方式,计及风电不确定性波动的区域电网火电调频机组配置方法的过程为:Specific implementation mode 1: This implementation mode is described in conjunction with FIG. 1 and FIG. 2. The process of configuring the thermal power frequency regulation unit configuration method of the regional power grid considering the uncertainty fluctuation of wind power is as follows:
步骤一:以Mallat小波分解和重构算法为工具,并选择db10作为小波基,进行风功率时间序列的分解和重构:首先,对采样间隔为nS的实测风功率数据进行小波分解,具体分解层数m由采样间隔决定,应保证分解的最后一层周期n·2m恰好为15min或者n·2m大于15min并且最接近15min,若n·2m与15min的差在3min内,则将第m层作为小时级别的小时平均风功率,若n·2m与15min的差大于3min,则将第m层与第m-1层进行重构,得到周期为小时级别的小时平均风功率;将后面的周期为秒级以及分钟级的分解层分别进行重构,得到原始风功率序列去掉小时平均风功率后的秒级、分钟级功率波动残差;Step 1: Use the Mallat wavelet decomposition and reconstruction algorithm as a tool, and select db10 as the wavelet base to decompose and reconstruct the wind power time series: first, perform wavelet decomposition on the measured wind power data with a sampling interval of nS, and specifically decompose The number of layers m is determined by the sampling interval. It should be ensured that the last layer period of decomposition n·2 m is exactly 15 min or n·2 m is greater than 15 min and the closest to 15 min. If the difference between n·2 m and 15 min is within 3 min, the The m-th layer is used as the hourly average wind power at the hourly level. If the difference between n·2 m and 15 min is greater than 3 min, the m-th layer and the m-1th layer are reconstructed to obtain the hourly average wind power at the hourly level; Reconstruct the second-level and minute-level decomposition layers of the subsequent periods to obtain the second-level and minute-level power fluctuation residuals after the hourly average wind power is removed from the original wind power sequence;
基于小波多尺度的分析方法,建立秒级、分钟级风电厂功率不确定性波动的瞬时模型,给出时域瞬时表达式;Based on the wavelet multi-scale analysis method, the instantaneous model of the second-level and minute-level wind power uncertainty fluctuations is established, and the time-domain instantaneous expression is given;
(1)分级风功率波动同风电场小时级平均功率的瞬时关系表达式(1) Instantaneous relationship expression between graded wind power fluctuation and hourly average power of wind farm
式中,σm为风电场输出功率分钟级波动的标准差,为风电场小时级平均功率,a、b、c为拟合系数,可通过最小二乘法拟合确定;In the formula, σm is the standard deviation of the minute-level fluctuation of the output power of the wind farm, is the hourly average power of the wind farm, a, b, and c are the fitting coefficients, which can be determined by least square fitting;
(2)秒级风功率波动同风电场小时级平均功率的瞬时关系表达式(2) Instantaneous relationship expression between the second-level wind power fluctuation and the hour-level average power of the wind farm
式中,σs为风电场输出功率秒级波动的标准差;In the formula, σ s is the standard deviation of the second-level fluctuation of the output power of the wind farm;
式(1)、(2)建立了秒级、分钟级风电厂功率不确定性波动的标准差同风电场小时级平均功率间的实时对应关系;时间分辨率为15分钟的风功率预测值恰好为小时级风功率,将其作为式(1)、(2)中的进行输入,对秒级、分钟级风电厂功率不确定性波动的范围进行实时预报;Formulas (1) and (2) establish the real-time correspondence between the standard deviation of the second-level and minute-level wind power uncertainty fluctuations and the hourly average power of the wind farm; the wind power prediction value with a time resolution of 15 minutes is exactly is the hour-level wind power, which is used as the formula (1) and (2) Input, real-time forecast for the range of second-level and minute-level wind power plant power uncertainty fluctuations;
步骤二:根据电厂的实际情况,建立用于调频分析的含风电区域电网模型,基于调频分析模型,给出表征系统一、二次调频能力的表达式:Step 2: According to the actual situation of the power plant, establish a regional power grid model including wind power for frequency regulation analysis, and based on the frequency regulation analysis model, give the expressions representing the primary and secondary frequency regulation capabilities of the system:
建立用于调频分析的含风电的区域电网模型,如图2所示;其中区域A中含有风电,区域B中只包含火电机组;Establish a regional power grid model with wind power for frequency modulation analysis, as shown in Figure 2; where area A contains wind power, and area B only includes thermal power units;
每个区域中分别含有一次调频通道以及二次调频通道,系统的输出为当前各区域的频率偏差χf(s),各区域的频率偏差χf(s)作为反馈信号通过一、二次调频通道实现对各自区域频率的一、二次调节;图中,αi为第i台机组的发电份额系数,δi为第i台火电机组的调差系数,Ri为参加二次调频机组的功率分配系数,BA、BB为各区域的频率偏差系数,KA、KB分别为各区域二次调频积分器增益;Gi(s)为第i台发电机组的传递函数,具体表达式如下:Each area contains a primary frequency modulation channel and a secondary frequency modulation channel. The output of the system is the current frequency deviation χ f (s) of each area, and the frequency deviation χ f (s) of each area is used as a feedback signal through the primary and secondary frequency modulation The channel realizes the primary and secondary adjustment of the frequency in each area; in the figure, α i is the power generation share coefficient of the i-th unit, δ i is the adjustment coefficient of the i-th thermal power unit, and R i is the frequency of the unit participating in the secondary frequency regulation. Power distribution coefficient, B A , B B are the frequency deviation coefficients of each area, K A , K B are the gains of the secondary frequency modulation integrator in each area respectively; G i (s) is the transfer function of the i-th generator set, specifically expressed as The formula is as follows:
其中,表示液压伺服电机的动态特性,Tss是液压伺服电机时间常数,取Tss=0.2s;表示汽轮机的容积动态特性,T0s是高压缸的容积时间常数;Ta∑表示等效转子时间常数,本系统中除风机外均为同步发电机,将所有同步发电机等效为一台同步发电机,再用功率份额系数乘以各自的转子时间常数,即可求出等效转子时间常数;βA、βB分别表示区域A和区域B的等效摩擦系数,与Ta∑的求取方法是一样的,也是根据功率份额系数来求取;负荷的波动、风功率的波动以及联络线功率的波动分别为χNL(s)、χWind(s)以及χPtie(s);in, Indicates the dynamic characteristics of the hydraulic servo motor, T s s is the time constant of the hydraulic servo motor, take T s s = 0.2s; Indicates the dynamic characteristics of the volume of the steam turbine, T 0 s is the volume time constant of the high-pressure cylinder; T a∑ indicates the equivalent rotor time constant, and all synchronous generators in this system except the fan are equivalent to one For a synchronous generator, the equivalent rotor time constant can be obtained by multiplying the power share coefficient by the respective rotor time constant; β A and β B represent the equivalent friction coefficients of area A and area B respectively , and the The calculation method is the same, and it is also calculated according to the power share coefficient; the load fluctuation, wind power fluctuation and tie line power fluctuation are respectively χ NL (s), χ Wind (s) and χ Ptie (s);
考虑风功率不确定性波动的电网一次调频能力,即仅在一次调频作用下,某段时间内秒级风功率波动方差与电网频率波动方差的比值,表达式为:The primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the second-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time under the action of only one frequency regulation, the expression is:
选取图2所示模型假定区域A负荷无波动,断开其二次调频通道即只考虑一次调频作用,可以计算得出电网频率变化与秒级风功率波动的频域解析表达式为:Select the model shown in Figure 2 assuming that there is no load fluctuation in area A, disconnect its secondary frequency modulation channel, that is, only consider the primary frequency modulation effect, and calculate the frequency domain analytical expression of the grid frequency change and second-level wind power fluctuation as follows:
其中, in,
设输入为零均值信号x(t),经其对应的输入-输出传递函数H(jω)作用后,得到输出为y(t),j为虚数,ω为角频率,则输出y(t)的方差为:Suppose the input is a zero-mean signal x(t), after the corresponding input-output transfer function H(jω), the output is y(t), j is an imaginary number, and ω is the angular frequency, then the output y(t) The variance of is:
式中Sy(ω)=Sx(ω)|H(jω)|2,Sy(ω)表示输出的功率谱密度,Sx(ω)表示输入的功率谱密度;In the formula, S y (ω)=S x (ω)|H(jω)| 2 , S y (ω) represents the power spectral density of the output, and S x (ω) represents the power spectral density of the input;
考虑到所涉及的变量为偏差量,均值为0,将式(5)代入式(6)中可得由秒级风功率波动造成的系统频率波动的方差 Considering that the variables involved are deviations with an average value of 0, substituting Equation (5) into Equation (6), the variance of the system frequency fluctuation caused by the second-level wind power fluctuation can be obtained
其中,Sw1(ω)为秒级风功率波动的功率谱密度;Among them, S w1 (ω) is the power spectral density of second-level wind power fluctuations;
由PSD时频转换计算机算法可以得到,σs(i)的功率谱密度在频域中的抽样可被近似为:It can be obtained from the PSD time-frequency conversion computer algorithm, the sampling of the power spectral density of σ s (i) in the frequency domain can be approximated as:
其中,MFFT(.)为快速傅里叶变换,N为采样长度,ωs为采样频率,E(·)为均值函数;根据香浓采样定理,当采样频率高于信号频率一倍以上时,连续信号可以从采样样本中完全重建出来;因此,选择适当的采样频率,通过式(8)可得到风功率秒级波动的功率谱密度;将式(8)作为输出信号的功率谱密度带入式(6)得到秒级风功率波动的方差为:Among them, MFFT (.) is the fast Fourier transform, N is the sampling length, ω s is the sampling frequency, and E(·) is the mean function; according to the Shannon sampling theorem, when the sampling frequency is more than twice the signal frequency , the continuous signal can be completely reconstructed from the sampling samples; therefore, by selecting an appropriate sampling frequency, the power spectral density of the second-level fluctuation of wind power can be obtained through formula (8); using formula (8) as the power spectral density band of the output signal Entering formula (6), the variance of the second-level wind power fluctuation is obtained as:
经过推导可以得到考虑风功率不确定性波动的电网一次调频能力的频域解析表达式为:After derivation, the frequency-domain analytical expression of the primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power can be obtained as:
其中,为秒级风功率波动的方差,为由秒级风功率波动造成的系统频率波动的方差,Sw1(ω)为秒级风功率波动的功率谱密度;in, is the variance of the second-level wind power fluctuation, is the variance of the system frequency fluctuation caused by the second-level wind power fluctuation, S w1 (ω) is the power spectral density of the second-level wind power fluctuation;
考虑风功率不确定性波动的电网二次调频能力,即仅在二次调频作用下,某段时间内分钟级风功率波动方差与电网频率波动方差的比值,表达式为:The secondary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the minute-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time only under the secondary frequency regulation, the expression is:
采用上述推导方法,同样可以得到分钟级风功率波动的方差以及由分钟级风功率波动造成的系统频率波动的方差经过推导可以得到考虑风功率不确定性波动的电网二次调频能力的频域解析表达式为:Using the above derivation method, the variance of minute-level wind power fluctuations can also be obtained and the variance of system frequency fluctuations caused by minute-scale wind power fluctuations After derivation, the frequency-domain analytical expression of the power grid's secondary frequency regulation capability considering wind power uncertainty fluctuations can be obtained as:
其中,为分钟级风功率波动的方差,为系统频率波动的方差,Sw2(ω)为分钟级风功率波动的功率谱密度;in, is the variance of minute-level wind power fluctuations, is the variance of the system frequency fluctuation, S w2 (ω) is the power spectral density of the minute-level wind power fluctuation;
步骤三:基于调频能力表达式,定量分析计算系统在不同条件下的一、二次调频能力。Step 3: Based on the frequency modulation capability expression, quantitatively analyze and calculate the primary and secondary frequency modulation capabilities of the system under different conditions.
具体实施方式二:本实施方式所述的步骤三中的建立用于调频分析的含风电的区域电网模型是运用Matlab/Simulink软件实现的。Embodiment 2: The establishment of a regional power grid model including wind power for frequency modulation analysis in step 3 described in this embodiment is realized by using Matlab/Simulink software.
其它步骤与具体实施方式一相同。Other steps are the same as in the first embodiment.
具体实施方式三:本实施方式所述的步骤三基于调频能力表达式定量分析计算系统在不同条件下的一、二次调频能力的实现过程为:Specific implementation mode three: Step three described in this embodiment is based on the quantitative analysis of the frequency modulation capability expression and the realization process of the primary and secondary frequency modulation capabilities of the calculation system under different conditions is as follows:
步骤1:保持火电一次调频机组比例不变,计算系统在不同调差系数下的一次调频能力;保持各机组调差系数不变,计算系统在不同火电一次调频机组比例的一次调频能力;根据计算结果,绘制以火电一次调频机组比例为横坐标,调差系数为纵坐标的表格,从表格中的数据统计出不同比例的火电一次调频机组以及不同调差系数对一次调频能力的影响规律;Step 1: Keeping the ratio of thermal power primary frequency regulation unit constant, calculate the primary frequency regulation capability of the system under different differential coefficients; keep the differential coefficient of each unit constant, and calculate the primary frequency regulation capability of the system in different thermal power primary frequency regulation unit ratios; according to the calculation As a result, draw a table with the proportion of thermal power primary frequency modulation units as the abscissa and the adjustment coefficient as the vertical axis, and from the data in the table, the influence rules of different proportions of thermal power primary frequency modulation units and different difference adjustment coefficients on the primary frequency regulation ability are obtained;
步骤2:保持火电二次调频机组比例不变,计算系统在不同积分器增益下的二次调频能力;保持各机组积分器增益不变,计算系统在不同火电二次调频机组比例的二次调频能力;根据计算结果,绘制以火电二次调频机组比例为横坐标,积分器增益为纵坐标的表格,从表格中的数据统计出不同比例的火电二次调频机组以及不同积分器增益对二次调频能力的影响规律;Step 2: Keeping the ratio of thermal power secondary frequency modulation units constant, calculate the secondary frequency modulation capability of the system under different integrator gains; keep the integrator gains of each unit constant, and calculate the secondary frequency modulation of the system under different thermal power secondary frequency modulation unit ratios capacity; according to the calculation results, draw a table with the proportion of thermal power secondary frequency modulation units as the abscissa and the integrator gain as the vertical axis, and calculate the different ratios of thermal power secondary frequency modulation units and different integrator gains for secondary Influence law of frequency modulation capability;
步骤3:依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法。Step 3: Based on the quantitative analysis results of Step 1 and Step 2, provide a thermal power unit configuration method that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations.
其它步骤与具体实施方式一相同。Other steps are the same as in the first embodiment.
具体实施方式四:本实施方式所述步骤3依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法的实现过程为:Specific Embodiment 4: Step 3 of this embodiment is based on the quantitative analysis results of Step 1 and Step 2 to provide a thermal power unit configuration method that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations. The implementation process is as follows:
步骤3.1.1:若A区域各机组调差系数δiA保持不变,DPFRA值为K1,K1为一个常数;当一次调频机组比例由p%增加至2p%时,DPFRA值增大至2K1;即若某一时刻风功率输出秒级波动量由P增加至k1·P,k1为一个常数,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k1·p%;Step 3.1.1: If the adjustment coefficient δ iA of each unit in area A remains unchanged, the value of D PFRA is K 1 , and K 1 is a constant; when the proportion of primary frequency adjustment units increases from p% to 2p%, the value of D PFRA increases as large as 2K 1 ; that is, if the second-level fluctuation of wind power output increases from P to k 1 ·P at a certain moment, k 1 is a constant, and the frequency is kept stable at the level when the wind power fluctuation does not increase. Increased from p% to k 1 ·p%;
步骤3.1.2:若A区域积分器增益KA不变,DSFRA值为K2,K2为假设的一个常数;当二次调频机组比例由p%增加至2p%时,DSFRA值增大至2K2;即若某一时刻风功率输出分钟级波动量由P增加至k2·P,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k2·p%。Step 3.1.2: If the gain K A of the integrator in area A remains unchanged, the value of D SFRA is K 2 , and K 2 is an assumed constant; when the proportion of the secondary frequency modulation unit increases from p% to 2p%, the value of D SFRA increases As large as 2K 2 ; that is, if the minute-level fluctuation of wind power output increases from P to k 2 ·P at a certain moment, the frequency is kept stable at the level when the wind power fluctuation does not increase, and the proportion of primary frequency modulation units is increased from p% to k 2 ·p%.
其它步骤与具体实施方式三相同。Other steps are the same as in the third embodiment.
具体实施方式五:本实施方式所述步骤3依据步骤1和步骤2的定量分析结果,提供能够有效抑制由风电场功率不确定性波动引起的系统频率波动的火电机组配置方法的实现过程为:Embodiment 5: Step 3 described in this embodiment is based on the quantitative analysis results of Step 1 and Step 2 to provide a thermal power unit configuration method that can effectively suppress system frequency fluctuations caused by wind farm power uncertainty fluctuations. The implementation process is as follows:
步骤3.2.1:若A区域中参与一次调频的机组比例保持不变,调节各机组的不等率δiA,DPFRA值与δiA间具有如下近似关系,即:Step 3.2.1: If the proportion of units participating in the primary frequency regulation in area A remains unchanged, adjust the differential rate δ iA of each unit, and the D PFRA value and δ iA have the following approximate relationship, namely:
即若某一时刻风功率输出秒级波动量由P增加至k1·P,k1为假设的一个常数,维持频率稳定在风功率波动未增加时的水平,将δiA减小至k1·δiA;That is, if the second-level fluctuation of wind power output increases from P to k 1 P at a certain moment, k 1 is a hypothetical constant, and the frequency is kept stable at the level when the wind power fluctuation does not increase, and δ iA is reduced to k 1 δ iA ;
步骤3.2.2:若A区域积分器增益KA不变,DSFRA值为K2,K2为假设的一个常数;当二次调频机组比例由p%增加至2p%时,DSFRA值增大至2K2;即若某一时刻风功率输出分钟级波动量由P增加至k2·P,维持频率稳定在风功率波动未增加时的水平,将一次调频机组比例由p%增至k2·p%。Step 3.2.2: If the gain K A of the integrator in area A remains unchanged, the value of D SFRA is K 2 , and K 2 is an assumed constant; when the proportion of the secondary frequency modulation unit increases from p% to 2p%, the value of D SFRA increases As large as 2K 2 ; that is, if the minute-level fluctuation of wind power output increases from P to k 2 ·P at a certain moment, the frequency is kept stable at the level when the wind power fluctuation does not increase, and the proportion of primary frequency modulation units is increased from p% to k 2 ·p%.
其它步骤与具体实施方式三相同。Other steps are the same as in the third embodiment.
具体实施例specific embodiment
以某电网实际一天的运行数据进行仿真。The simulation is carried out with the actual day's operation data of a power grid.
步骤一:以Mallat小波分解和重构算法为工具,并选择db10作为小波基,进行风功率时间序列的分解和重构。首先,对实测风功率数据(本专利示例数据的采样间隔为5S,时间长度为一个月的数据)进行8层分解;将前8层和第7层进行重构,得到周期为小时级别的小时平均风功率;将后面的1~3层、4~6分别进行重构,得到原始风功率序列去掉小时平均风功率后的秒级、分钟级功率波动残差(如图5所示)。如果,风速数据采样间隔为1S,则需进行10层分解后在进行重构,才能得到为小时级周期的平均风功率以及相应的波动残差。Step 1: Using the Mallat wavelet decomposition and reconstruction algorithm as a tool, and selecting db10 as the wavelet base, the wind power time series is decomposed and reconstructed. First, conduct 8-layer decomposition of the measured wind power data (the sampling interval of the patent sample data is 5S, and the time length is one month); reconstruct the first 8 layers and the 7th layer, and obtain the hour-level cycle Average wind power: Reconstruct the following layers 1-3 and 4-6 respectively to obtain the second-level and minute-level power fluctuation residuals after the hourly average wind power is removed from the original wind power sequence (as shown in Figure 5). If the sampling interval of wind speed data is 1S, it needs to be reconstructed after 10 layers of decomposition to obtain the average wind power and the corresponding fluctuation residual in the hour-level period.
Mallat小波分解和重构算法的示意图如图5所示。The schematic diagram of Mallat wavelet decomposition and reconstruction algorithm is shown in Fig. 5.
对秒级、分钟级风功率波动量时间序列取绝对值处理并按大小进行排序,并同风电场小时级平均功率时间序列建立起一一对应的点列关系。根据最小二乘拟合原理,利用3σ原理剔除野点,对点列对进行统计建模。用最小二乘拟合法对数据进行拟合,拟合结果如图7、8所示。Take the absolute value of the second-level and minute-level wind power fluctuation time series and sort them by size, and establish a one-to-one corresponding point-series relationship with the hour-level average power time series of the wind farm. According to the least squares fitting principle, the 3σ principle is used to eliminate outliers, and statistical modeling is carried out on the point column pairs. The data were fitted using the least squares fitting method, and the fitting results are shown in Figures 7 and 8.
基于上述统计建模方法,可以基于不同风电场的历史数据得到式(1)、(2)的秒级、分钟级风电厂功率不确定性波动的瞬时表达式。Based on the above statistical modeling method, the instantaneous expressions of the second-level and minute-level wind power uncertainty fluctuations of the formulas (1) and (2) can be obtained based on the historical data of different wind farms.
步骤二:调频模型的建立如图2所示,下面具体分析本发明给出的表征系统一、二次调频能力的表达式的推导过程。Step 2: The establishment of the frequency modulation model is shown in Figure 2. The derivation process of the expressions representing the primary and secondary frequency modulation capabilities of the system given by the present invention will be analyzed in detail below.
选取图2所示模型假定区域A负荷无波动,断开其二次调频通道即只考虑一次调频作用,可以计算得出电网频率变化与秒级风功率波动的频域解析表达式为:Select the model shown in Figure 2 assuming that there is no load fluctuation in area A, disconnect its secondary frequency modulation channel, that is, only consider the primary frequency modulation effect, and calculate the frequency domain analytical expression of the grid frequency change and second-level wind power fluctuation as follows:
其中, in,
设输入为零均值信号x(t),经其对应的输入-输出传递函数H(jω)作用后,得到输出为y(t),j为虚数,ω为角频率,则输出y(t)的方差为:Suppose the input is a zero-mean signal x(t), after the corresponding input-output transfer function H(jω), the output is y(t), j is an imaginary number, and ω is the angular frequency, then the output y(t) The variance of is:
式中Sy(ω)=Sx(ω)|H(jω)|2,Sy(ω)表示输出的功率谱密度,Sx(ω)表示输入的功率谱密度;In the formula, S y (ω)=S x (ω)|H(jω)| 2 , S y (ω) represents the power spectral density of the output, and S x (ω) represents the power spectral density of the input;
考虑到所涉及的变量为偏差量,均值为0,将式(3)代入式(4)中可得由秒级风功率波动造成的系统频率波动的方差 Considering that the variables involved are deviations with an average value of 0, substituting Equation (3) into Equation (4), the variance of system frequency fluctuations caused by second-level wind power fluctuations can be obtained
其中,Sw1(ω)为秒级风功率波动的功率谱密度;Among them, S w1 (ω) is the power spectral density of second-level wind power fluctuations;
由风电场功率波动PSD时频转换计算机算法可以得到,σs(i)的功率谱密度在频域中的抽样可被近似为:It can be obtained from the wind farm power fluctuation PSD time-frequency conversion computer algorithm, the sampling of the power spectral density of σ s (i) in the frequency domain can be approximated as:
其中,MFFT(.)为快速傅里叶变换,N为采样长度,ωs为采样频率,E(·)为均值函数;根据香浓采样定理,当采样频率高于信号频率一倍以上时,连续信号可以从采样样本中完全重建出来;因此,选择适当的采样频率,通过式(6)可得到风功率秒级波动的功率谱密度;将式(6)作为输出信号的功率谱密度带入式(4)得到秒级风功率波动的方差为:Among them, MFFT (.) is the fast Fourier transform, N is the sampling length, ω s is the sampling frequency, and E(·) is the mean function; according to the Shannon sampling theorem, when the sampling frequency is more than twice the signal frequency , the continuous signal can be completely reconstructed from the sampling samples; therefore, by selecting an appropriate sampling frequency, the power spectral density of the second-level fluctuation of wind power can be obtained through formula (6); using formula (6) as the power spectral density band of the output signal Entering formula (4), the variance of the second-level wind power fluctuation is obtained as:
考虑风功率不确定性波动的电网一次调频能力,即仅在一次调频作用下,某段时间内秒级风功率波动方差与电网频率波动方差的比值,表达式为:The primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the second-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time under the action of only one frequency regulation, the expression is:
考虑风功率不确定性波动的电网二次调频能力,即仅在二次调频作用下,某段时间内分钟级风功率波动方差与电网频率波动方差的比值,表达式为:The secondary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power, that is, the ratio of the minute-level wind power fluctuation variance to the power grid frequency fluctuation variance within a certain period of time only under the secondary frequency regulation, the expression is:
将表征电网频率方差的公式(5),及表征秒级风功率波动方差的公式(7)代入一次调频能力的动态表达式(8)即可得到考虑风功率不确定性波动的电网一次调频能力的频域解析表达式为:Substituting the formula (5) representing the grid frequency variance and the formula (7) representing the second-level wind power fluctuation variance into the dynamic expression (8) of the primary frequency regulation capability, the primary frequency regulation capability of the power grid considering the uncertainty fluctuation of wind power can be obtained The frequency domain analytical expression of is:
其中,为秒级风功率波动的方差,为由秒级风功率波动造成的系统频率波动的方差,Sw1(ω)为秒级风功率波动的功率谱密度;in, is the variance of the second-level wind power fluctuation, is the variance of the system frequency fluctuation caused by the second-level wind power fluctuation, S w1 (ω) is the power spectral density of the second-level wind power fluctuation;
采用上述推导方法,同样可以得到分钟级风功率波动的方差以及由分钟级风功率波动造成的系统频率波动的方差经过推导可以得到考虑风功率不确定性波动的电网二次调频能力的频域解析表达式为:Using the above derivation method, the variance of minute-level wind power fluctuations can also be obtained and the variance of system frequency fluctuations caused by minute-scale wind power fluctuations After derivation, the frequency-domain analytical expression of the power grid's secondary frequency regulation capability considering wind power uncertainty fluctuations can be obtained as:
其中,为分钟级风功率波动的方差,为系统频率波动的方差,Sw2(ω)为分钟级风功率波动的功率谱密度;in, is the variance of minute-level wind power fluctuations, is the variance of the system frequency fluctuation, S w2 (ω) is the power spectral density of the minute-level wind power fluctuation;
步骤三:基于调频能力表达式定量分析系统含有不同比例的火电调频机组时的一、二次调频能力;为调度部门配置火电调频机组提供参考方法,实现对风电场功率不确定性波动引起的系统频率波动的有效控制。Step 3: Quantitatively analyze the primary and secondary frequency regulation capabilities when the system contains different proportions of thermal power frequency regulation units based on the expression of frequency regulation capability; provide a reference method for the dispatching department to configure thermal power frequency regulation units, and realize the system for wind farm power uncertainty fluctuations Effective control of frequency fluctuations.
根据式(5)与式(7),定量分析系统中含有不同比例火电调频机组时系统的一、二次调频能力,结果应如表1、2所示(针对于不同的系统,计算结果可能有所不同)。According to formula (5) and formula (7), the primary and secondary frequency regulation capabilities of the system when the system contains different proportions of thermal power frequency regulation units are quantitatively analyzed, and the results should be shown in Tables 1 and 2 (for different systems, the calculation results may be vary).
表1 不同参数下的系统一次调频能力DPFCA Table 1 Primary frequency modulation capability D PFCA of the system under different parameters
其中,A为一次调频机组百分比,B为区域A的一次调频能力DPFRA,C为A区域各机组的不等率。Among them, A is the percentage of primary frequency regulation units, B is the primary frequency regulation capability D PFRA of area A, and C is the differential rate of each unit in area A.
表2 不同参数下的系统二次调频能力DSFRA Table 2 System secondary frequency modulation capability D SFRA under different parameters
其中,A为区域A中二次调频机组百分比,B为区域A的二次调频能力DSFRA,C为区域A的积分器增益KA的取值。Among them, A is the percentage of secondary frequency regulation units in area A, B is the secondary frequency regulation capability D SFRA of area A, and C is the value of integrator gain K A in area A.
DPFCA与DSFRA的计算可以表征系统当前对于风电功率波动的频率调节能力,DPFCA与DSFRA值增大一倍,表明系统对于风电功率波动的频率调节能力也增强一倍。针对于特定的系统,按上述方法计算系统调频能力,结合当前系统风电的接入情况,可以给出具体火电调频机组配置方法。The calculation of D PFCA and D SFRA can characterize the current frequency regulation ability of the system for wind power fluctuations. The double value of D PFCA and D SFRA indicates that the system's frequency regulation ability for wind power fluctuations is also doubled. For a specific system, the frequency regulation capability of the system is calculated according to the above method, and combined with the current system wind power access situation, the specific configuration method of thermal power frequency regulation units can be given.
在系统原有的火电调频机组配置情况下,系统频率波动如图3所示,在某些时间点超过系统对频率±0.1Hz的要求。当采用本发明提供的火电调频机组配置方法,系统频率波动如图4所示。系统频率波动减小,标准差由σ=0.00042885减小到σ=0.00021798。In the case of the original thermal power frequency modulation unit configuration of the system, the system frequency fluctuation is shown in Figure 3, and at some point exceeds the system's requirement for frequency ±0.1Hz. When adopting the thermal power frequency regulation unit configuration method provided by the present invention, the system frequency fluctuation is shown in Fig. 4 . The system frequency fluctuation is reduced, and the standard deviation is reduced from σ=0.00042885 to σ=0.00021798.
仿真分析结果表明,按本发明进行火电调频机组配置可以进一步减小风功率波动造成的系统频率波动,维持系统频率稳定。Simulation analysis results show that the configuration of thermal power frequency modulation units according to the present invention can further reduce system frequency fluctuations caused by wind power fluctuations and maintain system frequency stability.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201410486165.4A CN104201700B (en) | 2014-09-22 | 2014-09-22 | Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201410486165.4A CN104201700B (en) | 2014-09-22 | 2014-09-22 | Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation |
Publications (2)
Publication Number | Publication Date |
---|---|
CN104201700A CN104201700A (en) | 2014-12-10 |
CN104201700B true CN104201700B (en) | 2017-06-20 |
Family
ID=52086953
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201410486165.4A Expired - Fee Related CN104201700B (en) | 2014-09-22 | 2014-09-22 | Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN104201700B (en) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN104462839A (en) * | 2014-12-19 | 2015-03-25 | 哈尔滨工业大学 | Wind electricity uncertainty estimation method based on wind power fluctuation strength instant model |
CN104868469B (en) * | 2015-05-29 | 2017-11-03 | 中国电力科学研究院 | A kind of fired power generating unit start optimization method |
CN105303056B (en) * | 2015-11-16 | 2017-12-01 | 哈尔滨工业大学 | A kind of wind speed real-time change speed depicting method |
CN105914787B (en) * | 2016-05-25 | 2018-04-03 | 哈尔滨工业大学 | It is a kind of based on the instantaneous quantitative depicting method probabilistic with respect to the wind-powered electricity generation of pace of change of power |
CN108053097A (en) * | 2017-11-23 | 2018-05-18 | 上海电力学院 | The frequency-domain index test and evaluation method of primary frequency modulation performance |
CN107947200A (en) * | 2017-12-04 | 2018-04-20 | 长沙理工大学 | Method for determining frequency deviation coefficient of system containing wind power |
CN109995087B (en) * | 2017-12-29 | 2021-03-09 | 北京天诚同创电气有限公司 | Frequency modulation control method and device for power station and frequency modulation system |
CN108808699A (en) * | 2018-07-10 | 2018-11-13 | 华北电力大学(保定) | A kind of dual quadrant frequency-response analysis method suitable for bidirectional energy-storage equipment |
CN111313466A (en) * | 2020-03-09 | 2020-06-19 | 国网山东省电力公司电力科学研究院 | A method and system for optimal regulation of AGC of sending-end power grid based on wind priority regulation |
CN113011002A (en) * | 2021-02-22 | 2021-06-22 | 北京凌阳伟业科技有限公司 | Wind energy permeability limit evaluation method, system and device based on power spectral density |
CN113364813B (en) * | 2021-08-09 | 2021-10-29 | 新风光电子科技股份有限公司 | Compression transmission method and system for rail transit energy feedback data |
CN113839416B (en) * | 2021-09-13 | 2023-10-27 | 国网湖南省电力有限公司 | Method and device for determining maximum wind power access proportion based on frequency response model |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102594244A (en) * | 2012-02-20 | 2012-07-18 | 江苏省电力试验研究院有限公司 | Joint control method of primary frequency modulation for doubly-fed wind power generation set |
CN102820656A (en) * | 2012-08-25 | 2012-12-12 | 华北电力大学(保定) | Method for jointly scheduling power generation load by using wind power generation unit and thermal power generation unit |
CN103715720A (en) * | 2014-01-07 | 2014-04-09 | 哈尔滨工业大学 | High-permeability wind power primary and secondary backup coordination control method |
CN104037772A (en) * | 2014-06-12 | 2014-09-10 | 国家电网公司 | Interconnected power grid automatic gain control (AGC) frequency modulation unified controller and control method |
-
2014
- 2014-09-22 CN CN201410486165.4A patent/CN104201700B/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102594244A (en) * | 2012-02-20 | 2012-07-18 | 江苏省电力试验研究院有限公司 | Joint control method of primary frequency modulation for doubly-fed wind power generation set |
CN102820656A (en) * | 2012-08-25 | 2012-12-12 | 华北电力大学(保定) | Method for jointly scheduling power generation load by using wind power generation unit and thermal power generation unit |
CN103715720A (en) * | 2014-01-07 | 2014-04-09 | 哈尔滨工业大学 | High-permeability wind power primary and secondary backup coordination control method |
CN104037772A (en) * | 2014-06-12 | 2014-09-10 | 国家电网公司 | Interconnected power grid automatic gain control (AGC) frequency modulation unified controller and control method |
Also Published As
Publication number | Publication date |
---|---|
CN104201700A (en) | 2014-12-10 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN104201700B (en) | Meter and the regional power grid thermoelectricity frequency modulation crew qiting method of the uncertain fluctuation of wind-powered electricity generation | |
Ishraque et al. | Optimization of load dispatch strategies for an islanded microgrid connected with renewable energy sources | |
CN102542133B (en) | Short-time wind speed forecasting method and system for wind power plant | |
Jin et al. | Equivalent modeling of wind energy conversion considering overall effect of pitch angle controllers in wind farm | |
CN104899656A (en) | Wind power combined predication method based on ensemble average empirical mode decomposition and improved Elman neural network | |
CN105184391A (en) | Method for predicting wind speed and power of wind farm based on wavelet decomposition and support vector machine | |
Che et al. | A wind power forecasting system based on the weather research and forecasting model and Kalman filtering over a wind-farm in Japan | |
CN112036595B (en) | Short-term wind power prediction method and system based on multi-position numerical weather forecast | |
CN102055188A (en) | Ultra-short term wind power forecasting method based on time series method | |
Vigueras-Rodríguez et al. | Spectral coherence model for power fluctuations in a wind farm | |
Deng et al. | A new wind speed scenario generation method based on spatiotemporal dependency structure | |
CN105610192A (en) | On-line risk assessment method considering large-scale wind power integration | |
Guo et al. | A stochastic-process-based method for assessing frequency regulation ability of power systems with wind power fluctuations | |
Zhang et al. | Wind speed prediction with wavelet time series based on lorenz disturbance. | |
Kaplan et al. | A novel method based on Weibull distribution for short-term wind speed prediction | |
CN104504618A (en) | Micro-grid reliability evaluation data sampling method based on pair-copula function | |
CN103235984A (en) | Computing method of longitudinal moment probability distribution of power output of wind power station | |
CN103678940B (en) | Fluctuations in wind speed uncertainty estimation method based on effective turbulence intensity instantaneous model | |
Bo et al. | Short-term forecasting and uncertainty analysis of wind power | |
Mabel et al. | Adequacy evaluation of wind power generation systems | |
Yang et al. | A centralized power prediction method for large-scale wind power clusters based on dynamic graph neural network | |
Miao et al. | Fluctuation feature extraction of wind power | |
Roy | Impact of short duration wind variations on output of a pitch angle controlled turbine | |
CN104462839A (en) | Wind electricity uncertainty estimation method based on wind power fluctuation strength instant model | |
CN103065049B (en) | A kind of wind power real-time estimate computing method based on coif5 small echo real-time decomposition |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170620 |