CN103956746B - Based on the self adaptation low frequency deloading method of frequency change rate response - Google Patents

Abstract

Based on the self adaptation low frequency deloading method of frequency change rate response, 1, the frequency f of every platform generator in measured zone _g,j, every platform generator moment of inertia M _g,j, each load bus meritorious P _l,i, controling parameters first of adjusting; 2, system inertia centre frequency f in control centre zoning _coiwith region internal loading always meritorious P _l; 3, the f of every platform generator in control centre monitored area _g,jchange, if f _coicontinue lower than cutting load frequency threshold value f first _set, exceed cutting load time gate threshold value T first _set, go to step 4, otherwise go to step 3; 4, P is excised _{shed, 1}the load of %; 5, the moment that completes of note step 4 is T _shed, determine moment t1 and t2; 6, the actual initial meritorious vacancy DP of computing system _t=t0, 7, determine second time cutting load ratio P _{shed, 2}8, by P _{shed, 2}each load bus in region is transferred to, excision P from control centre _{shed, 2}the load of %; The inventive method can the change of effectively Adaptable System inertia, part throttle characteristics, meritorious vacancy, to adopt after the inventive method system frequency recovery effects comparatively by round low frequency deloading method and semi adaptive low frequency deloading method more excellent.

Description

Based on the self adaptation low frequency deloading method of frequency change rate response

Technical field

The invention belongs to power system security protection system technical field, be specifically related to a kind of self adaptation low frequency deloading method based on frequency change rate response.

Background technology

Frequency stability is one of large stability of electric power system three.The guarantee of the safe operation of generators in power systems group, load electric energy quality etc. all needs system frequency to maintain in deviation allowed band.It frequency stabilization question essence is system active balance problem.When system suffer serious disturbance cause large meritorious uneven time, system frequency may exceed deviation allowed band, will cause frequency collapse and system crash time serious.The key stoping frequency collapse event to occur is to excise the appropriate load that vacancy numerical value matches of gaining merit with system, the low frequency load shedding equipment large-scale application developed according to this thought in modern power network, as the essential measure preventing frequency unstability event.

Due to real system failure mode and operational mode changeable, the system that disturbance causes vacancy of gaining merit cannot be predicted in advance, how to ensure that low frequency load shedding equipment can excise the load matched with meritorious vacancy numerical value in various situations, become and determine that low frequency deloading method controls the key of validity and economy.In existing electric power system, be widely used by the thought of approaching the actual meritorious vacancy of system by round off-load, but there are some defects in it: fix discrete numerical value because employing makes the final cutting load amount performed be one group by round off-load, and real system gains merit vacancy continuous distribution in a sizable scope, the phenomenon of cutting, owing to cut was happened occasionally; In addition, for ensureing that Reliability of Microprocessor is by the adjacent two-wheeled action of round off-load at least one, the interval action delay of adjusting in advance, and when meritorious vacancy is comparatively large, system inertia is less, the falling process of frequency is very rapid, reaches frequency transient process before steady frequency recovers required value just occur unstable phenomenon in off-load amount.Even if after introduction off-load accelerating pulley is improved to semi adaptive UFLS scheme, its general principle is still identical with the thought of approaching by round, cannot eliminate though the defect produced is alleviated to some extent.

The core of self adaptation low frequency deloading method is how according to the actual meritorious vacancy size of frequency change rate response message determination current system.

Summary of the invention

In order to solve above-mentioned prior art Problems existing, the object of the present invention is to provide a kind of self adaptation low frequency deloading method based on frequency change rate response, method proposed by the invention can the change of effectively Adaptable System inertia, part throttle characteristics, meritorious vacancy, to adopt after the inventive method system frequency recovery effects comparatively by round low frequency deloading method and semi adaptive low frequency deloading method more excellent.

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

Based on the self adaptation low frequency deloading method of frequency change rate response, comprise the steps:

Step 1: the frequency f of every platform generator in measured zone _g,j, record the moment of inertia M of every platform generator _g,j, wherein, j=1,2 ... N supposes total N platform generator in region, measures the meritorious P of each load bus _l,i, wherein, i=1,2 ... M supposes total M load bus in region; To adjust controling parameters first, comprise cutting load frequency threshold value f first _set, cutting load time gate threshold value T first _set, cutting load ratio P first _{shed, 1};

Step 2: by the frequency f recorded in step 1 _g,jwith meritorious P _l,iby communication network transmission to control centre, according to system inertia centre frequency f in formula (a) zoning _coi, according to formula (b) zoning internal loading always meritorious P _l.

$f_{\mathrm{coi}}=\frac{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{f}_{G,j}\·M_j}{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{M}_j}---\left(a\right)$

$P_L=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{P}_i---\left(b\right)$

In formula: M _jthe moment of inertia of jth platform generator, P _ithe active power that i-th load bus absorbs;

Step 3: the frequency f of every platform generator in control centre monitored area _g,jchange, if frequency f _coicontinue lower than cutting load frequency threshold value f first _settime exceedes cutting load time gate threshold value T first _set, go to step 4, otherwise go to step 3;

Step 4: each load bus all excises P in region _{shed, 1}the load of %;

Step 5: the moment that completes of note step 4 is T _shed, determine moment t1 and t2 according to formula (c) and (d):

t1＝T _shed-Δt ₁(c)

t2＝T _shed+Δt ₂(d)

In formula: Δ t ₁t1 moment advanced T _shedduration, Δ t ₂t2 moment delayed T _shedduration, Δ t ₁with Δ t ₂value is generally tens ms; , value is generally tens ms;

Step 6: according to the actual initial meritorious vacancy Δ P of formula (e) computing system _t=t0, t0 is initial time after initial time and disturbance before system disturbance;

${\mathrm{\ΔP}}_{t=t0}=\frac{{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}}{{\frac{d{f}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}-{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2}}\·(P_{L,t=t1}-P_{L,t=t2})+(P_{L,t=t0}-P_{L,t=t1})---\left(e\right)$

In formula: be t1 and the t2 moment region in system inertia centre frequency rate of change; The t1 moment is that frequency becomes response sudden change previous moment, and the t2 moment is a moment after frequency change rate response sudden change; P _{l, t=t0}, P _{l, t=t1}, P _{l, t=t2}be system initial time before disturbance respectively, the region internal loading in t1 and t2 moment is always gained merit;

Step 7: determine second time cutting load ratio P according to formula (f) _{shed, 2}.

$P_{\mathrm{shed},2}=100\frac{{\mathrm{\ΔP}}_{t=t0}}{P_{L,t=0}}-P_{\mathrm{shed},1}---\left(f\right)$

Step 8: will second time cutting load ratio P _{shed, 2}each load bus in region is transferred to from control centre, each load bus excision P by communication network _{shed, 2}the load of %.

The derivation of (e) formula is explained as follows:

According to total system inertia centre frequency rate of change response theory, have

$M_{\mathrm{eq}}\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}=\mathrm{\ΔP}$

In formula: M _eq, f _coi, Δ P, t are system equivalent inertia respectively, system quantities centre frequency, and system is meritorious vacancy and time in real time; Wherein $M_{\mathrm{eq}}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{M}_{G,j}.$

Above formula is all applicable to frequency dynamic overall process, for t1 and the t2 moment, has

$M_{\mathrm{eq}}{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}={\mathrm{\ΔP}}_{t=t1}---\left(g\right),M_{\mathrm{eq}}{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2}={\mathrm{\ΔP}}_{t=t2}---\left(h\right)$

Wherein Δ P _t=t1=P _{m, t=t1}-P _{l, t=t1}-Δ P _{loss, t=t1}, Δ P _t=t2=P _{m, t=t2}-P _{l, t=t2}-Δ P _{loss, t=t2}

Δ P _t=t1, P _{m, t=t1}, Δ P _{loss, t=t1}when being t1 respectively, etching system is gained merit amount of unbalance, the total meritorious and circuit active loss of machinery; Δ P _t=t1, P _{m, t=t1}, Δ P _{loss, t=t1}when being t2 respectively, etching system is gained merit amount of unbalance, the total meritorious and circuit active loss of machinery.

With (g)-(h): $M_{\mathrm{eq}}({\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}-{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2})=(P_{m,t=t1}-P_{m,t=t2})-({\mathrm{\ΔP}}_{\mathrm{Loss},t=t1}-{\mathrm{\ΔP}}_{\mathrm{Loss},t=t2})-(P_{L,t=t1}-P_{L,t=t2})---\left(i\right)$

Consider as time period [t1, t2] enough short, and load is always gained merit and to be undergone mutation within this time period, then [t1, t2] machinery that in the time, Genset governor determines always the circuit active loss variable quantity that determines of meritorious variable quantity and system load flow numerically all much smaller than system loading always meritorious Sudden Changing Rate, then have for (e) is approximate

$M_{\mathrm{eq}}({\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}-{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2})=-(P_{L,t=t1}-P_{L,t=t2})---\left(j\right)$

If system is gained merit, initial vacancy is Δ P _t=t0, then P is had _{m, t=t0}=P _{l, t=t0}-Δ P _t=t0+ Δ P _{loss, t=t0}(k)

P in formula (k) _{m, t=t0}, Δ P _{loss, t=t0}be that after system disturbance, initial time machinery is total respectively to gain merit and initial time circuit active loss before disturbance;

(g) is launched, has $M_{\mathrm{eq}}{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}=P_{m,t=t1}-P_{L,t=t1}-{\mathrm{\ΔP}}_{\mathrm{Loss},t=t1}---\left(l\right)$

With (l)-(k),

$M_{\mathrm{eq}}{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}=P_{L,t=t0}-{\mathrm{\ΔP}}_{t=t0}-P_{L,t=t1}+(P_{m,t=t1}-P_{m,t=t0})-({\mathrm{\ΔP}}_{\mathrm{Loss},t=t1}-{\mathrm{\ΔP}}_{\mathrm{Loss},t=t0})---\left(m\right)$

Consider that the machinery that Genset governor determines always is gained merit at t=t0 and t=t1 moment numerical value close to (t1 moment system frequency is near 49Hz), circuit active loss absolute figure is very little, it is less at the changing value of t=t0 and t=t1, therefore in (m) formula, ignores (P _{m, t=t1}-P _{m, t=t0}) and (Δ P _{loss, t=t1}-Δ P _{loss, t=t0}) numerical value of two, have:

$M_{\mathrm{eq}}{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}=P_{L,t=t0}-{\mathrm{\ΔP}}_{t=t0}-P_{L,t=t1}---\left(n\right)$

With (n) (original text: (2))/(j), arrange to obtain (e) formula.

The present invention by excavating tradition by the impact that respond system frequency rate of change of cutting load first of round off-load, propose utilize the total meritorious information structure of moment system inertia centre frequency rate of change, region internal loading before and after cutting load first Accurate Estimation region in the actual vacancy expression formula of initially gaining merit of system.Around proposed expression formula, construct the complete low frequency deloading method control flow based on the response of system frequency rate of change.Based on typical examples, by with the Contrast on effect of tradition by round low frequency deloading method and semi adaptive low frequency deloading method, confirm that method proposed by the invention can the change of effectively Adaptable System inertia, part throttle characteristics, meritorious vacancy, to adopt after the inventive method system frequency recovery effects comparatively by round low frequency deloading method and semi adaptive low frequency deloading method more excellent.

Off-load method of the present invention using tradition by round off-load first cutting load as bring out system frequency rate of change response sudden change condition, by the actual initial meritorious vacancy of system frequency rate of change response sudden change accurate Calculation system, the difference of actual initial meritorious vacancy ratio and first cutting load ratio is second time cutting load ratio, twice cutting load amount sum equals the actual meritorious vacancy of system, makes system active balance, frequency retrieval after twice cutting load.

Accompanying drawing explanation

Fig. 1 is the self adaptation UFLS technic relization scheme schematic diagram based on frequency change rate response.

Fig. 2 is example system for use in carrying primary connection schematic diagram.

Fig. 3 is each off-load scheme works contrast one after excision 1, No. 11 machines.

Fig. 4 is each off-load scheme works contrast two after excision 1, No. 11 machines.

Fig. 5 be after excision No. 1 machine each off-load scheme works to one.

Fig. 6 is each off-load scheme works contrast two after excision No. 1 machine.

Fig. 7 is each off-load scheme works contrast one after excision 1,11, No. 13 machines.

Fig. 8 is each off-load scheme works contrast two after excision 1,11, No. 13 machines.

Each off-load scheme works contrast one when Fig. 9 is excision 1, No. 11 machine induction machine accountings 60%.

Each off-load scheme works contrast two when Figure 10 is excision 1, No. 11 machine induction machine accountings 60%.

Each off-load scheme works contrast one when Figure 11 is excision 1, No. 11 machine induction machine accountings 70%.

Each off-load scheme works contrast two when Figure 12 is excision 1, No. 11 machine induction machine accountings 70%.

Embodiment

Below in conjunction with drawings and the specific embodiments, the present invention is described in further detail.

Be illustrated in figure 2 IEEE30 system wiring figure, when investigation disturbance scene changes, part throttle characteristics change, superiority of the present invention and validity, specifically arranged as table 1.

Table 1 disturbance scene setting

For disturbance scenario A, explain the low frequency deloading method application process based on frequency change rate response.

When disturbance scenario A is set to 0.2s, 1, No. 11 machine comes off, and all loads are 50% induction motor+50% constant-impedance, and off line accident causes system vacancy of gaining merit to be 39.93%.

As shown in Figure 1, this example implements the self adaptation low frequency deloading method based on frequency change rate response, specific as follows:

Step 1: each generator of the inherent node 1,2,5,8,11,13 in region, measures the frequency f of these six generators respectively _g,j, the moment of inertia of record six generators is [M _{g, 1}m _{g, 2}m _{g, 3}m _{g, 4}m _{g, 5}m _{g, 6}]=[6.067.165.725.26.925.28] (s).The each load of the inherent node 2,3,4,5,7,8,10,12,14,15,16,17,18,19,20,21,23,24,26,29,30 in region, measures these 21 load buses and to gain merit P _l,i.Adjust controling parameters first, first cutting load frequency threshold value f _setbe set to 49Hz, first cutting load time gate threshold value T _setbe set to 0.15s, first cutting load ratio P _{shed, 1}be set to 7.

Step 2: by the f recorded in step one _g,jand P _l,iby communication network transmission to control centre, according to system inertia centre frequency f in formula (a) zoning _coi, the generator wherein due to the 1st, No. 11 node is cut, the moment of inertia M of these two generators _{g, 1}=0, M _{g, 5}=0.According to formula (b) zoning internal loading always meritorious P _l.

$f_{\mathrm{coi}}=\frac{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{f}_{G,j}\·M_j}{\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{M}_j}---\left(a\right)$

$P_L=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{P}_i---\left(b\right)$

Step 3: monitoring f _coichange, find at 0.88sf _coicontinue lower than the 49Hz time more than 0.15s, go to step 4.

Step 4: each load bus all excises the load of 7% in region.

Step 5: step 4 complete moment T _shedfor 0.88s, determine moment t1 and t2 according to formula (c) and (d):

t1＝T _shed-Δt ₁(c)

t2＝T _shed+Δt ₂(d)

Get Δ t ₁=30ms, Δ t ₂=70ms, therefore t1=0.85s, t2=0.95s.

Step 6: according to the actual initial meritorious vacancy Δ P of formula (e) computing system _t=t0, initial time t0=0s. before system disturbance

${\mathrm{\ΔP}}_{t=t0}=\frac{{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}}{{\frac{d{f}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}-{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2}}\·(P_{L,t=t1}-P_{L,t=t2})+(P_{L,t=t0}-P_{L,t=t1})---\left(e\right)$

Table 2 is system inertia centre frequency rate of change situation before and after cutting load first

P in formula (e) _{l, t=t0}=2.8304.

In order to avoid single-point is sampled the error brought during Practical Calculation, calculate p _t=t1, P _t=t2numerical value time, suitable filtering algorithm can be adopted, this example adopt average algorithm, as follows:

$\stackrel{\‾}{{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t1}}=\frac{{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t1-10\mathrm{ms}}+{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t1}+{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t1+10\mathrm{ms}}}{3},\stackrel{\‾}{P_{t=t1}}=\frac{P_{t=t1-10\mathrm{ms}}+P_{t=t1}+P_{t=t1+10\mathrm{ms}}}{3}$

$\stackrel{\‾}{{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t2}}=\frac{{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t2-10\mathrm{ms}}+{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t2}+{\frac{\mathrm{df}}{\mathrm{dt}}}_{t=t2+10\mathrm{ms}}}{3},\stackrel{\‾}{P_{t=t2}}=\frac{P_{t=t2-10\mathrm{ms}}+P_{t=t2}+P_{t=t2+10\mathrm{ms}}}{3}$

With replace

Therefore have ${\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t1}=-1.7768\mathrm{Hz}/s,{\frac{{\mathrm{df}}_{\mathrm{coi}}}{\mathrm{dt}}}_{t=t2}=-1.4279\mathrm{Hz}/s,$ P _t＝t1=2.5633p.u，P _t＝t2=2.4067p.u,P _L,t＝t0=2.8304.

(e) formula of substitution calculates Δ P _t=t0=1.0661

Step 7: determine second time cutting load ratio P according to formula (f) _{shed, 2}.

$P_{\mathrm{shed},2}=100\frac{{\mathrm{\ΔP}}_{t=t0}}{P_{L,t=0}}-P_{\mathrm{shed},1}=30.67$

Step 8: by numerical value P _{shed, 2}being transferred to each load bus in region by communication network from control centre, considering that various delay amounts to 100ms, the 1.05s load in each load bus excision 30.67%. twice cutting load adds up to the load of excision 37.67%.

In order to contrast adaptive control effect of the present invention, choose certain general by round a scheme, certain general by round b scheme, certain is general by round c scheme, accelerate front the 2 semi adaptive a schemes of taking turns based on by round a scheme, carries out Contrast on effect based on semi adaptive b scheme five kinds of schemes of taking turns by round a scheme acceleration front 3.

Certain is general in round a scheme for table 3

Certain is general in round b scheme for table 4

Certain is general in round c scheme for table 5

Semi adaptive a scheme is taken turns for accelerating to cut second when cutting the first round by round a scheme simultaneously, and semi adaptive b scheme is taken turns for accelerating to cut second and third when cutting the first round by round a scheme simultaneously.

Under disturbance scenario A, the contrast effect of each scheme is shown in Fig. 3 and accompanying drawing 4; As can be seen from the figure: adopting the present invention program, to control (duration 40s) system low-limit frequency in rear whole dynamic process the highest in six kinds of control programs, system highest frequency is than by round a scheme, low by round b scheme, semi adaptive a scheme, semi adaptive b scheme.After controlling by round c scheme, system there occurs frequency unstable phenomenon (low-limit frequency is lower than 47.5Hz); By round a scheme, control rear system there occurs frequency over control (highest frequency is higher than 51.5Hz) by round b scheme, semi adaptive a scheme, semi adaptive b scheme; And utilize the present invention program to control rear whole dynamic process medium frequency rate of change response curve all to meet the requirements.Comprehensively it seems that the present invention program's control effects is optimum in whole six kinds of control programs.

Under disturbance scenario B, the contrast effect of each scheme is shown in Fig. 5 and Fig. 6, as can be seen from the figure: adopting the present invention program, to control (duration 40s) system low-limit frequency in rear whole dynamic process the highest in six kinds of control programs, system highest frequency is than by round a scheme, low by round c scheme, semi adaptive a scheme, semi adaptive b scheme.After controlling by round a scheme, semi adaptive a scheme, semi adaptive b scheme, system there occurs frequency over control (highest frequency is higher than 51.5Hz); Utilize the present invention program to control rear whole dynamic process medium frequency rate of change response curve all to meet the requirements.Comprehensively it seems that the present invention program's control effects is optimum in whole six kinds of control programs.

Under disturbance scene C, the contrast effect of each scheme is shown in Fig. 7 and Fig. 8, as can be seen from the figure: adopting the present invention program, to control (duration 40s) system low-limit frequency in rear whole dynamic process the highest in six kinds of control programs, system highest frequency is than low by round a scheme, semi adaptive a scheme, semi adaptive b scheme.By round b scheme, there occurs frequency unstable phenomenon (low-limit frequency is lower than 47.5Hz) by system after the control of round c scheme; After controlling by round a scheme, semi adaptive a scheme, semi adaptive b scheme, system there occurs frequency over control (highest frequency is higher than 51.5Hz); Utilize the present invention program to control rear whole dynamic process medium frequency rate of change response curve all to meet the requirements.Comprehensively it seems that the present invention program's control effects is optimum in whole six kinds of control programs.

Under disturbance scene D, the contrast effect of each scheme is shown in Fig. 9 and Figure 10, as can be seen from the figure: adopting the present invention program, to control (duration 40s) system low-limit frequency in rear whole dynamic process the highest in six kinds of control programs, system highest frequency is than low by round a scheme, semi adaptive a scheme, semi adaptive b scheme.After controlling by round c scheme, system there occurs frequency unstable phenomenon (low-limit frequency is lower than 47.5Hz); After controlling by round a scheme, semi adaptive a scheme, semi adaptive b scheme, system there occurs frequency over control (highest frequency is higher than 51.5Hz); And utilize the present invention program to control rear whole dynamic process medium frequency rate of change response curve all to meet the requirements.Comprehensively it seems that the present invention program's control effects is optimum in whole six kinds of control programs.

Under disturbance scene E, the contrast effect of each scheme is shown in Figure 11 and Figure 12, as can be seen from the figure: adopting the present invention program, to control (duration 40s) system low-limit frequency in rear whole dynamic process the highest in six kinds of control programs, system highest frequency is than low by round a scheme, semi adaptive a scheme, semi adaptive b scheme.After controlling by round c scheme, system there occurs frequency unstable phenomenon (low-limit frequency is lower than 47.5Hz); After controlling by round a scheme, system there occurs frequency over control (highest frequency is higher than 51.5Hz); And utilize the present invention program to control rear whole dynamic process medium frequency rate of change response curve all to meet the requirements.Comprehensively it seems that the present invention program's control effects is optimum in whole six kinds of control programs.

Disturbance scenario A, B, C have different systems initially meritorious vacancy and system inertia, and the present invention program all has good control effects under three kinds of scenes, illustrate that the present invention program effectively can be adaptive to system and to gain merit the change of vacancy and system inertia.

Disturbance scenario A, D, E have different part throttle characteristics, and the present invention program all has good control effects under three kinds of scenes, illustrate that the present invention program can the change of effective self adaptation part throttle characteristics.

Claims (1)

1., based on the self adaptation low frequency deloading method of frequency change rate response, it is characterized in that: comprise the steps:

Step 1: the frequency f of every platform generator in measured zone _g,j, record the moment of inertia M of every platform generator _g,j, wherein, j=1,2 ... N supposes total N platform generator in region, measures the meritorious P of each load bus _l,i, wherein, i=1,2 ... M supposes total M load bus in region; To adjust controling parameters first, comprise cutting load frequency threshold value f first _set, cutting load time gate threshold value T first _set, cutting load ratio P first _{shed, 1};

Step 2: by the frequency f recorded in step 1 _g,jwith meritorious P _l,iby communication network transmission to control centre, according to system inertia centre frequency f in formula (a) zoning _coi, according to formula (b) zoning internal loading always meritorious P _l;

$f_{coi}=\frac{\underset{j=1}{\overset{N}{\Σ}}{f}_{G,j}\·M_j}{\underset{j=1}{\overset{N}{\Σ}}{M}_j}---\left(a\right)$

$P_L=\underset{i=1}{\overset{M}{\Σ}}{P}_i---\left(b\right)$

In formula: M _jthe moment of inertia of jth platform generator, P _ithe active power that i-th load bus absorbs;

Step 3: the frequency f of every platform generator in control centre monitored area _g,jchange, if frequency f _coicontinue lower than cutting load frequency threshold value f first _settime exceedes cutting load time gate threshold value T first _set, go to step 4, otherwise go to step 3;

Step 4: each load bus all excises P in region _{shed, 1}the load of %;

Step 5: the moment that completes of note step 4 is T _shed, determine moment t1 and t2 according to formula (c) and (d):

t1＝T _shed-Δt ₁(c)

t2＝T _shed+Δt ₂(d)

In formula: Δ t ₁t1 moment advanced T _shedduration, Δ t ₂t2 moment delayed T _shedduration, Δ t ₁with Δ t ₂value is tens ms;

Step 6: according to the actual initial meritorious vacancy Δ P of formula (e) computing system _t=t0, t0 is initial time before system disturbance;

${\mathrm{\ΔP}}_{t=t0}=\frac{{\frac{{\mathrm{df}}_{coi}}{dt}}_{t=t1}}{{\frac{{\mathrm{df}}_{coi}}{dt}}_{t=t1}-{\frac{{\mathrm{df}}_{coi}}{dt}}_{t=t2}}\·\left(P_{L,t=t1}-P_{L,t=t2}\right)+\left(P_{L,t=t0}-P_{L,t=t1}\right)---\left(e\right)$

In formula: be t1 and the t2 moment region in system inertia centre frequency rate of change; The t1 moment is that frequency becomes response sudden change previous moment, and the t2 moment is a moment after frequency change rate response sudden change; P _{l, t=t0}, P _{l, t=t1}, P _{l, t=t2}be system initial time before disturbance respectively, the region internal loading in t1 and t2 moment is always gained merit;

Step 7: determine second time cutting load ratio P according to formula (f) _{shed, 2};

$P_{shed,2}=100\frac{{\mathrm{\ΔP}}_{t=t0}}{P_{L,t=t0}}-P_{shed,1}---\left(f\right)$

Step 8: will second time cutting load ratio P _{shed, 2}each load bus in region is transferred to from control centre, each load bus excision P by communication network _{shed, 2}the load of %.