CN105356502A - Contact line steady-state limit determination method suitable for wind power utilization - Google Patents

Abstract

The present invention provides a contact line steady-state limit determination method suitable for wind power utilization. The method comprises the steps of (1) calculating a target contact line fluctuation power Pt caused by the fluctuation power of a wind power node and a load node in a grid system, (2) calculating the adjustable rate of the grid system to the target contact line fluctuation power, (3) calculating the controlled capacity of the grid system to the target contact line fluctuation power, (4) calculating the critical controllable period Tg of the grid system to the target contact line fluctuation power, (5) filtering the target contact line fluctuation power by using a Chebyshev filter with 1/Tg as filtering frequency and obtaining a high frequency component and a low frequency component, and (6) calculating a target contact line steady-state transmission limit. According to the steady-state limit determination method, only the keep of power transmission margin for an uncontrollable fluctuation component is needed, and a larger power transmission space is provided for wind power utilization.

Description

A kind of interconnection stable state limit defining method being applicable to wind electricity digestion

Technical field

The invention belongs to and relate to a kind of interconnection stable state limit defining method, be specifically related to a kind of interconnection stable state limit defining method being applicable to wind electricity digestion.

Background technology

China's Wind Power Generation Industry sustained and rapid development, within 2014, newly-increased wind-powered electricity generation installation amount refreshes historical record.But China's wind power resources mainly concentrates on " three Norths " area, with load center spatially in contrary distribution, after large-scale wind power networks, when one's respective area wind electricity digestion capability is not enough, for avoiding abandoning wind in a large number, the transregional problem of dissolving of wind-powered electricity generation will certainly be caused.This research so-called " net net is interactive " and transregional the dissolving of the wind-powered electricity generation that carries out completes mainly through interconnection, in order to electric power netting safe running with more reasonably arrange wind-powered electricity generation exchange power, needs to determine interconnection limit transmitted power in advance.

Mainly contain Total transfer capability TTC (TotalTransferCapability-abbreviation TTC) research for limit transmitted power research at present, the TTC research under existing traditional constraints, also comprise the TTC research after large-scale wind power introducing.TTC refers to that, under the certain stable state of electric power system or transient state constraint, the limit power that certain transmission cross-section can transmit, its emphasis is all kinds of security constraint of consideration system, and is not the transmission of electricity limit of interconnection self.

At present for the interconnection own power limit, the method generally by calculating ampacity is analyzed, and mainly contains static heat fixed value method and Dynamic Thermal fixed value method.Electric current flows through the rising that transmission of electricity element (hereinafter referred to as conductor) can cause conductor temperature, and cause the increase of conductor sag and stress, the restriction of these machineries from conductor itself and physics can be converted into the restriction of conductor temperature simultaneously.And for conductor, its temperature is determined by the acting in conjunction by the electric current of conductor, illumination, heat loss through convection and heat loss through radiation.When so-called static heat definite value instructs body current-carrying synchronous with its temperature exactly, the current-carrying value corresponding to the maximum allowable temperature of conductor.This is also to the hot definite value of conductor current-carrying basic understandings originally and the foundation of engineering construction power engineering circle people.Static heat definite value can off-line setting calculation, also can on-line tuning.The former is the way of people under environmental condition fixing situation, namely traditional maximum permission ampacity, and latter is the way on real-time measurement basis, is the one of real-time hot definite value technology practical function.Dynamic Thermal definite value is from dynamic equation of heat balance, considers the asynchronism between the change of conductor current-carrying and variations in temperature, embodies conductor temperature defining in various durations, namely characterize the hot definite value of conductor with temperature.Why being referred to as dynamically, is that this process terminates, and gets back to again static heat definite value, so this concept often all correspond to the time of a continuity because it embodies is the transient process of temperature change.Dynamic Thermal fixed value method improves the deficiency that static heat definite value is too guarded, and determines line energizing flow ability in real time, improve to certain limit the ability to transmit electricity of interconnection according to wire on-line operation state and meteorological condition etc.Static heat definite value and Dynamic Thermal definite value are all determine its transmission of electricity limit, i.e. physics limit of the through-put power of interconnection according to interconnection loadability.

Compared with traditional load, wind-powered electricity generation shows the fluctuation on stronger randomness and Different time scales, but prediction level is lower than load prediction.Large-scale wind power is grid-connected brings a large amount of uncertain fluctuation to interconnection, if still using interconnection physics limit as the power delivery limit, then may owing to not taking into full account that interconnection brings a large amount of uncertain fluctuation in actual motion, the problem such as cause interconnection out-of-limit; If consider the impact that the fluctuation of interconnection uncertainty brings completely, then may cause interconnection transmission limit excessive descent, cause the problems such as For Congestion.Therefore be necessary to consider the strong probabilistic impact of wind-powered electricity generation, explore the interconnection transmission limit defining method of safe and reasonable more, ensure wind electricity digestion and system safety operation.

Summary of the invention

In order to overcome above-mentioned the deficiencies in the prior art, the invention provides a kind of interconnection stable state limit defining method being applicable to wind electricity digestion, stable state limit defining method of the present invention is only required to be uncontrollable wave component and reserves transmission of electricity surplus, for wind electricity digestion provides larger transmission of electricity space.

In order to realize foregoing invention object, the present invention takes following technical scheme:

Be applicable to an interconnection stable state limit defining method for wind electricity digestion, described method comprises the steps:

(1) the target interconnection fluctuating power Pt that the fluctuating power calculating network system apoplexy electrical nodes and load bus causes;

(2) network system is calculated to the adj sp of described target interconnection fluctuating power;

(3) network system is calculated to the controlled capacity of described target interconnection fluctuating power;

(4) network system is calculated to the critical controllable period Tg of described target interconnection fluctuating power;

(5) be that rate ripple frequency adopts Chebyshev filter to carry out filtering to described target interconnection fluctuating power with 1/Tg, obtain high fdrequency component and low frequency component two parts;

(6) target interconnection stable state transmission limit is obtained.

Preferably, in described step (1), the computing formula of described target interconnection fluctuating power Pt is as follows:

$P_t=\underset{i\∈N}{\Σ}{A}_{i-l}{P}_i$

In formula, Pt is target interconnection random fluctuation power, and N is uncertain node set, P _ifor the predicted value of wind-powered electricity generation or negative rules node power, A _i-lfor node i is to the transfer ratio of branch road l, namely network system interior joint i increases unit and to gain merit the branch road l effective power flow variable quantity of exerting oneself caused.

Preferably, in described step (2), the adj sp calculating described target interconnection fluctuating power comprises and calculates all adjustable generator set control node in network system to the maximum power regulations speed R of described target interconnection fluctuating power, and the optimal adjustment speed r of each adjustable generator set control node _g, computing formula is as follows:

$\begin{array}{ccc}\max & R=-\underset{g\∈P}{\Σ}{A}_{g-l}{r}_g& \left(1\right)\\ s.t.& \underset{g\∈P}{\Σ}{A}_{g-l}{r}_g-\underset{i\∈N}{\Σ}{A}_{i-l}{r}_i\≤0& \left(2\right)\\ & \underset{i\∈N}{\Σ}{r}_i+\underset{g\∈P}{\Σ}{r}_g=0& \left(3\right)\\ & \frac{r_i}{r_j}=\frac{V_i}{V_j}\left(i,j\∈N\right)& \left(4\right)\\ & \left|r_g\right|\≤r_{gu}\left(g\∈P\right)& \left(5\right)\end{array}$

In formula, A is generating transfer distribution factor matrix, wherein A _i-lfor node i is to the transfer ratio of branch road l, A _g-lfor adjustable generator set control node g is to the transfer ratio of branch road l; r _i, r _jfor load or wind-powered electricity generation random fluctuation node i, j power fluctuation speed; r _gfor adjustable generator set control node power regulations speed; r _gufor the adjustable generator set control node power regulations speed upper limit; P is adjustable generator set control node set; N is the wind-powered electricity generation and the load fluctuation node set that cause probabilistic power; V _i, V _jfor the maximum power fluctuation amplitude of wind-powered electricity generation and negative rules node i, j.

Preferably, in described step (3), the controlled capacity of described target interconnection fluctuating power is the maximum control capability Psmax that all generator set control nodes reach on described target interconnection, and computational process is as follows:

The availability coefficient K of step 3-1, computing system Controlling vertex capacity _g

$K_g=\underset{g\∈P}{min}(P_{g\max }/r_g)$

In formula, Pgmax is the maximum control capability of each Controlling vertex, r _gfor the regulations speed of the optimum of adjustable generator set control node g, P is the set of Systematical control node, and min (.) is for asking for minimum value function;

Step 3-2, computing system are to the maximum control capability Psmax of target interconnection

$P_{s\max }=\underset{g\∈P}{\Σ}{A}_{g-l}{K}_g{r}_g$

In formula, A _g-lfor adjustable generator set control node g is to the transfer ratio of branch road l, namely in network system, adjustable generator set control node g increases unit and to gain merit the branch road l effective power flow variable quantity of exerting oneself caused, r _gfor the regulations speed r of the optimum of adjustable generator set control node g _g, P is the set of Systematical control node, and Psmax is the maximum control capability that all generator set control nodes reach on described target interconnection.

Preferably, in described step (4), comprise the steps:

Step 4-1, fourier series decomposition is carried out to the target interconnection fluctuating power Pt in future time period, decompose the sine wave obtaining several different frequencies and different amplitude; Frequency is arranged from small to large, is designated as f ₀, f ₁, f ₂f _n, corresponding amplitude is designated as A respectively ₀, A ₁, A ₂a _n

Step 4-2, re-construct one group of sine curve P _s, its medium frequency gets f respectively ₀, f ₁, f ₂f _n, corresponding amplitude is $A_0,\sqrt{{A_0}^2+{A_1}^2},\sqrt{{A_0}^2+{A_1}^2+{A_2}^2}...\sqrt{{A_0}^2+{A_1}^2+{A_2}^2+\·\·\·{A_n}^2\mathrm{...}}\mathrm{....};$

Step 4-3, according to regulations speed R computing system sine curve group P _stracking effect index CR _t, until find f ₀, f ₁, f ₂f _nin the sine curve of a certain frequency, make CR _t=ε, then the cycle that this frequency is corresponding and critical controllable period T _g, wherein, ε is control effects critical value, and whether can tracing preset cycle Sine wave, value depends on electrical network actual operating state, is the sine wave of T for the cycle, if tracking rate CR if being used for weighing unit _t> ε, then indication cycle is that the sine wave of T is controlled; If CR _t< ε, then indication cycle is that the sine wave of T is uncontrollable.

Preferably, in described step 4-3, described according to regulations speed R computing system sine curve group P _stracking effect index CR _t, comprise the steps:

Step 4-3-1, initial time regional control power of the assembling unit P _g(0)=0, setting integration step is dt, wherein T/dt > 1000;

Step 4-3-2, at power rising part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)>=R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)+R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

Step 4-3-3, in power drop part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)≤-R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)-R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

Step 4-3-4, repetition step 4-3-2 and step 4-3-3, until emulation terminates to time T;

Step 4-3-5, calculating unit power integral with sinusoidal fluctuation power integral tracking rate is calculated according to power of the assembling unit anomalous integral sinusoidal fluctuation power integral:

${\mathrm{CR}}_T=\frac{P_{gsum}}{P_{ssum}}\&times;100\%.$

Preferably, described step (6) comprises the steps:

Step 6-1, using described high fdrequency component as the uncontrollable component of Part I;

Step 6-2, amplitude in described low frequency component is greater than the part of system control capability Psmax as the uncontrollable component of Part II, using remainder as controlled component;

Step 6-3, using uncontrollable for described Part I component and described Part II uncontrollable component superposition as target interconnection fluctuation in uncontrollable total amount;

Step 6-4, known interconnection physics limit is deducted described uncontrollable total amount, obtain considering the interconnection stable state transmission limit under system fading margin speed.

Compared with prior art, beneficial effect of the present invention is:

The present invention introducing wind-powered electricity generation uncertainty fluctuation after, with using physics limit compared with stable state transmission limit, defining method more can ensure the fail safe of system; Stable state limit defining method of the present invention is only required to be uncontrollable wave component and reserves transmission of electricity surplus, for wind electricity digestion provides larger transmission of electricity space, is more suitable for dissolving of wind-powered electricity generation.

Accompanying drawing explanation

Fig. 1 is a kind of interconnection stable state limit defining method flow chart being applicable to wind electricity digestion provided by the invention

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further detail.

As shown in Figure 1, a kind of interconnection stable state limit defining method being applicable to wind electricity digestion, this method comprises the steps:

1, the target interconnection fluctuating power Pt that the fluctuating power calculating network system apoplexy electrical nodes and load bus causes;

The uncertainty fluctuation calculating wind-powered electricity generation and load bus in network system causes the power fluctuation Pt of target interconnection, and computing formula is:

$P_t=\underset{i\&Element;N}{\&Sigma;}{A}_{i-l}{P}_i$

Wherein Pt is interconnection random fluctuation power, and N is uncertain node set, and Pi is the predicted value of wind-powered electricity generation or negative rules node power.A _i-lfor generating transfer distribution factor GSDF matrix element, implication is the transfer ratio of node i to branch road l, is defined as: network system interior joint i increases unit and to gain merit the branch road l effective power flow variable quantity of exerting oneself caused.

2, network system is calculated to the adj sp of described target interconnection fluctuating power;

According to above-mentioned requirements, for (1)-(5), adopt the regulations speed r of method computing system for the maximal regulated speed R of target interconnection and the optimum of each adjustable generator set control node of linear programming _g:

$\begin{array}{ccc}\max & R=-\underset{g\&Element;P}{\&Sigma;}{A}_{g-l}{r}_g& \left(1\right)\\ s.t.& \underset{g\&Element;P}{\&Sigma;}{A}_{g-l}{r}_g-\underset{i\&Element;N}{\&Sigma;}{A}_{i-l}{r}_i\&le;0& \left(2\right)\\ & \underset{i\&Element;N}{\&Sigma;}{r}_i+\underset{g\&Element;P}{\&Sigma;}{r}_g=0& \left(3\right)\\ & \frac{r_i}{r_j}=\frac{V_i}{V_j}\left(i,j\&Element;N\right)& \left(4\right)\\ & \left|r_g\right|\&le;r_{gu}\left(g\&Element;P\right)& \left(5\right)\end{array}$

Wherein A is generating transfer distribution factor matrix, wherein A _i-lfor node i is to the transfer ratio of branch road l, A _i-lfor node g is to the transfer ratio of branch road l; r _i, r _jfor load or wind-powered electricity generation random fluctuation node i, j power fluctuation speed; r _gfor adjustable generator set control node power regulations speed; r _gufor the adjustable generator set control node power regulations speed upper limit; P is adjustable generator set control node set; N is the wind-powered electricity generation and the load fluctuation node set that cause probabilistic power; V _i, V _jfor the maximum power fluctuation amplitude of wind-powered electricity generation and negative rules node i, j.

Formula (1) represents linear programming target function: ask for the system maximal regulated speed met the demands, when node regulations speed being transferred to interconnection by GSDF, the power positive direction that node transfers to interconnection is consistent with initial trend, and the target of linear programming asks for the ability of Reverse Turning Control trend, therefore add negative sign; Formula (2) represents that the acting in conjunction of Controlling vertex and uncertain node makes target link line power fluctuation be 0, and due to target dominant eigenvalues because uncertain node is used as load bus process, its transfer ratio adopts LSDF; Formula (3) represent system main-control power and total uncertain power keep balancing and then; Formula (4) represents the ratio of each uncertain node power fluctuation speed, is directly proportional to its fluctuation amplitude; Formula (5) then represents the restriction of each Controlling vertex power adjustments speed.

3, network system is calculated to the controlled capacity of described target interconnection fluctuating power;

The controlled capacity of system to interconnection depends on the pondage of each Controlling vertex, then the regulations speed r of optimum according to each adjustable generator set control node obtained in step 2 _g, the control capability Psmax of system to target interconnection can be obtained.

The availability coefficient K of first computing system Controlling vertex capacity _g

$K_g=\underset{g\&Element;P}{min}(P_{g\max }/r_g)$

Pgmax is the maximum control capability of each Controlling vertex, r _gfor the regulations speed r of the optimum of adjustable generator set control node g _g, P is the set of Systematical control node, and min (.) is for asking for minimum value function.

Computing system is to the control capability Psmax of target interconnection again

$P_{s\max }=\underset{g\&Element;P}{\&Sigma;}{A}_{g-l}{K}_g{r}_g$

Wherein, A _g-lfor GSDF matrix element, implication be adjustable generator set control node g to the transfer ratio of branch road l, be defined as: in network system, adjustable generator set control node g increases unit and to gain merit the branch road l effective power flow variable quantity .r exerting oneself caused _gfor the regulations speed r of the optimum of adjustable generator set control node g _g, P is the set of Systematical control node.

4, network system is calculated to the critical controllable period Tg of described target interconnection fluctuating power;

Concrete steps:

(1) fourier series decomposition is carried out to the target interconnection fluctuating power Pt in future time period (as 15min), decompose the sine wave obtaining several different frequencies and different amplitude.Frequency is arranged from small to large, is designated as f ₀, f ₁, f ₂f _n, corresponding amplitude is designated as A respectively ₀, A ₁, A ₂a _n...

(2) one group of sine curve P is re-constructed _s, its medium frequency gets f respectively ₀, f ₁, f ₂f _n, corresponding amplitude is $A_0,\sqrt{{A_0}^2+{A_1}^2},\sqrt{{A_0}^2+{A_1}^2+{A_2}^2}...\sqrt{{A_0}^2+{A_1}^2+{A_2}^2+\&CenterDot;\&CenterDot;\&CenterDot;{A_n}^2\mathrm{...}}\mathrm{.....}$

(3) according to regulations speed R computing system for sine curve group P in formula (2) _stracking effect index CR _t, until find f ₀, f ₁, f ₂f _nin the sine curve of a certain frequency, make CR _t=ε, then the cycle that this frequency is corresponding and critical period T _g.

Wherein, ε is control effects critical value, and whether can tracing preset cycle Sine wave, value depends on electrical network actual operating state if being used for weighing unit; Be the sine wave of T for the cycle, if tracking rate CR _t> ε, then indication cycle is that the sine wave of T is controlled; Otherwise, if CR _t< ε, then think that the cycle is that the sine wave of T is uncontrollable.

CR is calculated according to regulations speed _tflow process as follows:

A, initial time regional control power of the assembling unit P _g(0)=0, setting integration step is dt, wherein T/dt > 1000;

B, at power rising part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)>=R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)+R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

C, in power drop part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)≤-R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)-R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

D, repetition step b and step c, until emulation terminates to time T;

E, calculating unit power integral with sinusoidal fluctuation power integral tracking rate is calculated according to power of the assembling unit anomalous integral sinusoidal fluctuation power integral:

5, be that rate ripple frequency adopts Chebyshev filter to carry out filtering to described target interconnection fluctuating power with 1/Tg, obtain high fdrequency component and low frequency component two parts;

6, target interconnection stable state transmission limit is obtained.

1) using high fdrequency component as the uncontrollable component of Part I;

2) part amplitude in low frequency component being greater than system control capability Psmax as the uncontrollable component of Part II, using remainder as controlled component;

3) uncontrollable for Part I component and the uncontrollable component of Part II are superposed as the uncontrollable total amount in the fluctuation of target interconnection;

4) physics limit is deducted uncontrollable total amount, the interconnection stable state transmission limit under consideration system fading margin speed can be obtained.

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment to invention has been detailed description, those of ordinary skill in the field are to be understood that: still can modify to the specific embodiment of the present invention or equivalent replacement, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.

Claims (7)

1. be applicable to an interconnection stable state limit defining method for wind electricity digestion, it is characterized in that, described method comprises the steps:

(1) the target interconnection fluctuating power Pt that the fluctuating power calculating network system apoplexy electrical nodes and load bus causes;

(2) network system is calculated to the adj sp of described target interconnection fluctuating power;

(3) network system is calculated to the controlled capacity of described target interconnection fluctuating power;

(4) network system is calculated to the critical controllable period Tg of described target interconnection fluctuating power;

(5) be that rate ripple frequency adopts Chebyshev filter to carry out filtering to described target interconnection fluctuating power with 1/Tg, obtain high fdrequency component and low frequency component two parts;

(6) target interconnection stable state transmission limit is obtained.

2. defining method according to claim 1, it is characterized in that, in described step (1), the computing formula of described target interconnection fluctuating power Pt is as follows:

In formula, Pt is target interconnection random fluctuation power, and N is uncertain node set, P _ifor the predicted value of wind-powered electricity generation or negative rules node power, A _i-lfor node i is to the transfer ratio of branch road l, namely network system interior joint i increases unit and to gain merit the branch road l effective power flow variable quantity of exerting oneself caused.

3. defining method according to claim 1, it is characterized in that, in described step (2), the adj sp calculating described target interconnection fluctuating power comprises and calculates all adjustable generator set control node in network system to the maximum power regulations speed R of described target interconnection fluctuating power, and the optimal adjustment speed r of each adjustable generator set control node _g, computing formula is as follows:

A in formula _i-lfor node i is to the transfer ratio of branch road l, A _g-lfor adjustable generator set control node g is to the transfer ratio of branch road l; r _i, r _jfor load or wind-powered electricity generation random fluctuation node i, j power fluctuation speed; r _gfor adjustable generator set control node power regulations speed; r _gufor the adjustable generator set control node power regulations speed upper limit; P is adjustable generator set control node set; N is the wind-powered electricity generation and the load fluctuation node set that cause probabilistic power; V _i, V _jfor the maximum power fluctuation amplitude of wind-powered electricity generation and negative rules node i, j.

4. defining method according to claim 1, it is characterized in that, in described step (3), the controlled capacity of described target interconnection fluctuating power is the maximum control capability Psmax that all generator set control nodes reach on described target interconnection, and computational process is as follows:

The availability coefficient K of step 3-1, computing system Controlling vertex capacity _g

In formula, Pgmax is the maximum control capability of each Controlling vertex, r _gfor the regulations speed of the optimum of adjustable generator set control node g, P is the set of Systematical control node, and min (.) is for asking for minimum value function;

Step 3-2, computing system are to the maximum control capability Psmax of target interconnection

In formula, A _g-lfor adjustable generator set control node g is to the transfer ratio of branch road l, namely in network system, adjustable generator set control node g increases unit and to gain merit the branch road l effective power flow variable quantity of exerting oneself caused, r _gfor the regulations speed r of the optimum of adjustable generator set control node g _g, P is the set of Systematical control node, and Psmax is the maximum control capability that all generator set control nodes reach on described target interconnection.

5. defining method according to claim 1, is characterized in that, in described step (4), comprise the steps:

Step 4-1, fourier series decomposition is carried out to the target interconnection fluctuating power Pt in future time period, decompose the sine wave obtaining several different frequencies and different amplitude; Frequency is arranged from small to large, is designated as f ₀, f ₁, f ₂f _n, corresponding amplitude is designated as A respectively ₀, A ₁, A ₂a _n

Step 4-2, re-construct one group of sine curve P _s, its medium frequency gets f respectively ₀, f ₁, f ₂f _n, corresponding amplitude is

Step 4-3, according to regulations speed R computing system sine curve group P _stracking effect index CR _t, until find f ₀, f ₁, f ₂f _nin the sine curve of a certain frequency, make CR _t=ε, then the cycle that this frequency is corresponding and critical controllable period T _g, wherein, ε is control effects critical value, and whether can tracing preset cycle Sine wave, value depends on electrical network actual operating state, is the sine wave of T for the cycle, if tracking rate CR if being used for weighing unit _t> ε, then indication cycle is that the sine wave of T is controlled; If CR _t< ε, then indication cycle is that the sine wave of T is uncontrollable.

6. defining method according to claim 5, is characterized in that, in described step 4-3, described according to regulations speed R computing system sine curve group P _stracking effect index CR _t, comprise the steps:

Step 4-3-1, initial time regional control power of the assembling unit P _g(0)=0, setting integration step is dt, wherein T/dt > 1000;

Step 4-3-2, at power rising part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)>=R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)+R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

Step 4-3-3, in power drop part, the current emulation cycle power of the assembling unit is P _gt (), next emulation cycle sinusoidal fluctuation power is P _s(t+1), unit maximal regulated speed is R _gif, P _s(t+1)-P _g(t)≤-R _gdt, then next emulation cycle power of the assembling unit P _g(t+1)=P _g(t)-R _gdt, otherwise next emulation cycle power of the assembling unit is: P _g(t+1)=P _s(t+1);

Step 4-3-4, repetition step 4-3-2 and step 4-3-3, until emulation terminates to time T;

Step 4-3-5, calculating unit power integral with sinusoidal fluctuation power integral tracking rate is calculated according to power of the assembling unit anomalous integral sinusoidal fluctuation power integral:

7. defining method according to claim 1, it is characterized in that, described step (6) comprises the steps:

Step 6-1, using described high fdrequency component as the uncontrollable component of Part I;

Step 6-2, amplitude in described low frequency component is greater than the part of system control capability Psmax as the uncontrollable component of Part II, using remainder as controlled component;

Step 6-3, using uncontrollable for described Part I component and described Part II uncontrollable component superposition as target interconnection fluctuation in uncontrollable total amount;

Step 6-4, known interconnection physics limit is deducted described uncontrollable total amount, obtain considering the interconnection stable state transmission limit under system fading margin speed.