CN101895121A - Low-frequency and low-voltage load-reducing control method based on multi-agent technology - Google Patents

Abstract

The invention provides a low-frequency and low-voltage load-reducing control method based on a multi-agent technology, which comprises two processes carried out simultaneously, wherein, in process 1, a local reaction layer triggers a device to act and implement load-shedding control after judging the device meets an action condition according to the measured state quantity information in real time such as local voltage, frequency and the like; and the process 2 comprises the following steps: 1. the local reaction layer uploads the local state quantity information and the actual load-shedding capacity of the device to local coordination layers; 2. the local coordination layers upload a data analysis result to sub-region coordination layers; 3. the sub-region coordination layers calculate local deloading and weighting coefficients for the local coordination layers, and meanwhile upload an information analysis result to a total-network coordination layer; and 4. the total-network coordination layer gathers information uploaded by the sub-region coordination layers, calculates sharply reduced indexes of power-receiving power of a power grid and sub-region deloading and acceleration coefficients for the sub-region coordination layers, sends the indexes and the coefficients to the sub-region coordination layers, and finally sends to the local coordination layers from the sub-region coordination layers.

Description

Low-frequency and low-voltage load-reducing control method based on multi-agent technology

Technical field

The invention belongs to power system stability control field, the present invention relates to a kind of new type of control method that realizes electrical network automatic low-frequency low-voltage load shedding based on multi-agent technology more precisely.

Background technology

The control of electric power system automatic load-reducing is to prevent electrical network, and especially the important technical of stability disruption and large area blackout takes place after suffering extremely serious disturbance the receiving end electrical network.

Power shortage after suddenly taking place in electrical network, and about the same for the load capacity and the operating generate output that guarantee to keep operation, and the voltage, frequency that recover each node in the electrical network rapidly must dispose the automatic load-reducing control device to rated value.

Existing low-frequency and low-voltage load-reducing control only by the measurement voltage on the spot or the decline situation triggering load shedding control device action of frequency state amount, divides round to implement load shedding.In the action logic of device, do not consider distant place information; And in a single day the load shedding scheme adjusts, and just no longer changes with the variation of actual condition.

Analyze and l-G simulation test all shows, the dynamic or frequency dynamic of the voltage of different nodes life period distribution phenomenon not only in the dynamic process after electric power system is disturbed, and usually have the spatial distribution phenomenon.Especially the electrical network big to those scales, that the region span is wide, topological structure is complicated, internodal voltage dynamically or frequency dynamic may exist than big-difference.Rely on traditional low frequency load shedding control strategy that only adopts local frequency to measure, or the low pressure load shedding control strategy that only adopts local voltage to measure, be difficult in control algolithm in real time, take into account between the Disturbed Power Systems node voltage dynamically or the spatial distribution phenomenon of frequency dynamic; Fixing load shedding scheme also is difficult to the variation of adaptive system operating condition preferably, thereby serious undershooting or control excessively may occur.In other words, the variation of depending merely on local voltage measurement or frequency measurement is difficult to embody the difference of the disturbed degree of different nodes in the electrical network, also can't adjust the load shedding control strategy in time when operating condition changes.For the assurance electrical network all can return on the acceptable level at voltage that suffers all nodes under the situation of any disturbance and frequency, but common way is the abundant cutting load of configuration in electrical network at present.Analysis and research to a large amount of real systems show that above-mentioned way tends to cause device action excessive, causes unnecessary economic loss.

Obviously, traditional low-frequency and low-voltage load-reducing control method is not owing to take into account the different node voltages of Disturbed Power Systems dynamically or the spatial distribution of frequency dynamic in control algolithm in real time, and can't change according to actual condition the load shedding control strategy is adjusted, there is the danger of owing to control or cross control, may causes serious consequence power grid security or economical operation.For this reason, need a kind ofly can in control algolithm in real time, to take into account different node voltages dynamically and the influence of frequency dynamic spatial distribution, and can adjust the load shedding control strategy automatically according to the variation of operating condition, thereby the adaptive system actual operating mode reduces the new type of control method that load shedding is controlled cost better.

Summary of the invention

The objective of the invention is:

How at electrical network, especially the receiving end electrical network suffers to take into account in the dynamic process after the big disturbance difference of the disturbed degree of different nodes, and improve the low-frequency and low-voltage load-reducing control strategy in view of the above, reduce load shedding control cost, make the variation of adaptive system actual operating mode preferably of load shedding control strategy simultaneously.

For achieving the above object, the present invention adopts following technical scheme to formulate the control system structure: at first at the contingent extreme catastrophe failure of electrical network under the various working, carry out the macromethod research of system safety stability characteristic (quality), layout in conjunction with topological structure of electric and the actual of low-frequency and low-voltage load-reducing control device, electrical network is divided into one or several child partitions, and each child partition is divided into several partial-block; In each child partition, select certain load-center substation to be set to the subarea cooperation layer of multi-agent system, if have a plurality of subareas cooperation layer in the electrical network, therefrom select certain subarea cooperation layer as the whole network cooperation layer, in each partial-block, choose the local cooperation layer that certain load-center substation is set to multi-agent system; Low-frequency and low-voltage load-reducing control device in the electrical network is set to the situ reaction layer of multi-agent system; Situ reaction layer, local cooperation layer, subarea cooperation layer and the whole network cooperation layer constitute a layered distribution type multi-agent system, the situ reaction layer only with its under the local cooperation layer of partial-block establish a communications link; Local cooperation layer only with its under the subarea cooperation layer of child partition establish a communications link; The subarea cooperation layer only establishes a communications link with the whole network cooperation layer.

If electrical network is divided into DMAX child partition, promptly multi-agent system comprises DMAX subarea cooperation layer.Wherein, d (d=1,2 ..., DMAX) individual subarea cooperation layer comprises CMAX.d local cooperation layer; C.d (c.d=1,2 ..., CMAX.d) individual local cooperation layer comprises RMAX.c.d situ reaction layer, r.c.d (r.c.d=1,2 ..., RMAX.c.d) represent r situ reaction layer in c the local cooperation layer of d subarea cooperation layer.

The present invention takes following technical scheme to realize the control system action, and this scheme comprises two processes of carrying out simultaneously, particularly:

In the process 1, the situ reaction layer according to the device installation place bus of measuring in real time with regard to quantity of state information such as ground voltage, frequencies, cutting load control is implemented in trigger equipment action when decision maker satisfies operation condition, comprises the following steps:

1.1, the voltage U of engraving device installation place bus when situ reaction layer r.c.d measures t in real time _R.c.d(t) and rate of change U ' _R.c.d(t), frequency f _R.c.d(t) and rate of change f ' _R.c.dAnd utilize above-mentioned information to judge whether electrical network suffers big disturbance and whether locking device moves (t); Simultaneously, but the situ reaction layer also is responsible for statistics current working lower device reality cutting load amount P _R.c.d

1.2, if the front and back double samplings constantly the busbar voltage fluctuation and frequency fluctuation all in the deviation range that normal operation is allowed (usually, voltage deviation is no more than ± and 5%, frequency departure is no more than ± 0.2Hz), decision-making system voltage, frequency all are in normal condition, but updating device reality cutting load amount P _R.c.dBe this moment statistical value; Otherwise, P _R.c.dKeep the statistical value of a last sampling instant constant.

1.3, if t constantly the time situ reaction layer r.c.d corresponding intrument be in blocking, go to step 1.1; Otherwise, judge according to voltage of measuring on the spot or frequency dynamic response whether the current time device satisfies operation condition, if do not satisfy operation condition, go to step 1.1; If satisfying operation condition then moves by the load shedding control strategy trigger equipment of current time.

1.4, if certain all round of situ reaction layer corresponding intrument all move, show that in the subsequent dynamic process this device can't continue from electrical network excision and load, finish the control of this device; Otherwise, return next measurement and judgement constantly of step 1.1 beginning.

In the process 2, carry out information interaction in the multi-agent system between each layer proxy, generate the matching system current working to instruct the situ reaction layer, and take into account the load shedding control strategy of voltage in the dynamic process, frequency dynamic spatial distribution, comprise the following steps:

2.1, if t constantly situ reaction layer decision-making system voltage, frequency be in normal condition, put its corresponding average voltage and fall to fall and be 0 with average frequency; Otherwise, utilize the average voltage of formula (1) engraving device installation place bus when calculating t in real time to fall, the average frequency of engraving device installation place bus falls when utilizing formula (2-1) or formula (2-2) to calculate t, but and is uploaded to local cooperation layer c.d in the lump with the device reality cutting load amount information in this moment.

$\mathrm{\Δ}{U}_{r.c.d}\left(t\right)=\frac{U_0-U_{r.c.d}\left(t\right)+\mathrm{\Δ}{U}_{r.c.d}\left(t^{\′}\right)}{2}---\left(1\right)$

${\mathrm{\Δf}}_{r.c.d}\left(t\right)=\frac{f_0-f_{r.c.d}\left(t\right)+f_{r.c.d}^{\′}\left(t\right)\·(t_c+t_{\mathrm{pre}}-t)+{\mathrm{\Δf}}_{r.c.d}\left(t^{\′}\right)}{2}---(2-1)$

${\mathrm{\Δf}}_{r.c.d}\left(t\right)=\frac{f_0-f_{r.c.d}\left(t\right)+{\mathrm{\Δf}}_{r.c.d}\left(t^{\′}\right)}{2}---(2-2)$

Wherein:

A) t ' is a last sampling instant, U ₀Be rated voltage, f ₀Be rated frequency, at China's electrical network, f ₀=50Hz;

B) if t constantly the time low frequency load shedding control device first run do not move, utilize formula (2-1) to calculate average frequency and fall; t _cBe the device blocking time; t _PreBe the predicted time window, with reference to time-delay length setting value in the low frequency load shedding control at present, span is 0.1～0.2s;

C) if t constantly the time low frequency load shedding control device first run move, utilize formula (2-2) to calculate average frequency and fall.

2.2, local cooperation layer c.d average voltage that all situ reaction layers in the partial-block electrical network of place are uploaded falls to fall with average frequency and carries out dynamic order respectively, utilize formula (3-1) to calculate the electric voltage dropping index of place partial-block electrical network, the frequency of utilizing formula (3-2) to calculate place partial-block electrical network is fallen index; Simultaneously, but local cooperation layer c.d also gathers the device reality cutting load amount of all situ reaction layers in the partial-block electrical network of place, but obtains partial-block cutting load amount P _C.d, and The above results is uploaded in the lump the subarea cooperation layer d of child partition under it;

${\mathrm{\ΔU}}_{c.d}=w\·{\mathrm{\Δ}\stackrel{\‾}{U}}_{r.c.d}+(1-w)\·\mathrm{\Δ}{U}_{\max .r}---(3-1)$

$\mathrm{\Δ}{f}_{c.d}=w\·\mathrm{\Δ}{\stackrel{\‾}{f}}_{r.c.d}+(1-w)\·\mathrm{\Δ}{f}_{\max .r}---(3-2)$

In the formula, Δ U _Max.r(Δ f _Max.r) and

The average voltage that is respectively all situ reaction layers in the partial-block electrical network of local cooperation layer c.d place falls the maximum and the mean value of (average frequency falls); W (0≤w≤1.0) is a weighted factor, and its numerical value is determined according to the off-line analysis result to concrete electrical network.

But 2.3, all local cooperation layers are uploaded in the child partition electrical network of cooperation layer d real-time statistics place, subarea partial-block cutting load amount, but obtain the child partition cutting load amount P of current time _d, and remember that but the difference that child partition cutting load amount under the initial operating mode and the child partition in this moment can the amounts of cutting is Δ P _dIf voltage, the frequency at bus place, cooperation layer d place, current time subarea all are in normal condition, measure this child partition electrical network from major network initially gone into power, if voltage or frequency are dangerous constantly for this, initially to be gone into power and Δ P _dDifference gone into power P as this child partition electrical network from major network actual _TL.dSimultaneously, electric voltage dropping index that subarea cooperation layer d uploads each local cooperation layer in the child partition electrical network of place and frequency are fallen index and are carried out dynamic order respectively, electric voltage dropping index and the frequency of utilizing formula (4-1) and formula (4-2) to calculate place child partition electrical network are respectively fallen index, but and electric voltage dropping index, frequency are fallen index, gone into power and child partition cutting load amount is uploaded to the whole network cooperation layer.

$\mathrm{\Δ}{U}_d=w\·\mathrm{\Δ}{\stackrel{\‾}{U}}_{c.d}+(1-w)\·\mathrm{\Δ}{U}_{\max .c}---(4-1)$

$\mathrm{\Δ}{f}_d=w\·\mathrm{\Δ}{\stackrel{\‾}{f}}_{c.d}+(1-w)\·\mathrm{\Δ}{f}_{\max .c}---(4-2)$

In the formula, Δ U _Max.c(Δ f _Max.c) and

Be respectively the maximum and the mean value of the electric voltage dropping index (frequency is fallen index) that each local cooperation layer is uploaded in the child partition electrical network of cooperation layer c.d place, subarea.

The subarea cooperation layer also falls index dynamic order result according to electric voltage dropping index and frequency that local cooperation layer is uploaded, and the local off-load that calculates at each local cooperation layer in this cooperation layer place, subarea child partition electrical network increases the weight of coefficient F _L, whether increase the weight of cutting load: F with the load shedding control device of judging each partial-block in this child partition _LIncreased the weight of the cutting load amount at 〉=0 o'clock; F _LReduced the cutting load amount at＜0 o'clock, it calculates principle as described in 2.3.1 and the 2.3.2.

2.3.1 local off-load increases the weight of coefficient F _LBe initialized as 0;

2.3.2 to the low pressure load shedding, if the maximum difference between the electric voltage dropping index that each local cooperation layer is uploaded in the child partition electrical network of cooperation layer d place, subarea is not less than U _Err(U _ErrBe electric voltage dropping difference setting value, value is 0.1pu), then utilize the F of formula (5-1) calculating at local cooperation layer c.d _L

$F_L=2\·(\mathrm{\Δ}{U}_{c.d}-\mathrm{\Δ}{\stackrel{\‾}{U}}_{c.d})---(5-1)$

To the low frequency load shedding, if the maximum difference that the frequency that each local cooperation layer is uploaded in the child partition electrical network of cooperation layer d place, subarea is fallen between index is not less than f _Err(f _ErrFor local frequencies is fallen poor setting value, value is 0.1Hz), then utilize the F of formula (5-2) calculating at local cooperation layer c.d _L

$F_L=2\·(\mathrm{\Δ}{f}_{c.d}-\mathrm{\Δ}{\stackrel{\‾}{f}}_{c.d})---(5-2)$

2.4, the whole network cooperation layer gathers each subarea cooperation layer in real time and uploads information, obtains the actual power total amount P that gone into of current time electrical network _{The TL ∑}But with electrical network reality cutting load total amount P _{The LS ∑}, the electrical network that execution in step 2.4.1～2.4.3 calculates at each subarea cooperation layer is subjected to electrical power bust index F _wAnd it is issued to each subarea cooperation layer.

2.4.1 electrical network is subjected to electrical power bust index F _W-Be initialized as 1.0;

2.4.2 if cooperation layer d place, subarea child partition electrical network from major network be subjected to power that electric channel gone into by certain on the occasion of sporting zero and continue for some time (adjust and be 0.1s), the corresponding electric channel that is subjected to of judging this child partition cut-offs, the whole network cooperation layer to all cut-off gone into passage cut-off before the power of transmission add up and be designated as P ' _{The TL ∑}, the electrical network that calculates at each subarea cooperation layer is subjected to electrical power bust index

2.4.3 if the whole network cooperation layer monitors P _{The TL ∑}Sport zero and continue 0.1s, judge the lonely network operation of the disturbed back of electrical network the whole network, upgrade this moment to be subjected to electrical power bust index at the electrical network of each subarea cooperation layer

Simultaneously, the whole network cooperation layer falls index dynamic order result according to electric voltage dropping index and frequency that each subarea cooperation layer is uploaded, calculates the subarea off-load accelerator coefficient F at each subarea cooperation layer _SAnd be issued to each subarea cooperation layer.Subarea off-load accelerator coefficient F _SBe used to judge whether the load shedding control device in each child partition quickens next round or cancel this round action: F _SQuickened the next round action at=1 o'clock; F _SDo not quicken in=0 o'clock; F _SCancelled the action of this round at=-1 o'clock.Subarea off-load accelerator coefficient F _SBe initialized as 0.Only there is a child partition as if electrical network, then the subarea off-load accelerator coefficient F of this child partition _SBe constantly equal to 0.

To the low pressure load shedding control of a plurality of child partitions, F _SThe assignment principle is as described in the 2.4.4:

2.4.4 if the maximum difference between the electric voltage dropping index that each subarea cooperation layer is uploaded is less than U _Err, at the subarea off-load accelerator coefficient F of each subarea cooperation layer _SBe 0; Otherwise:

1. if the electric voltage dropping index of cooperation layer d place, subarea child partition electrical network is not less than Δ U _Max(Δ U _MaxFor maximum voltage falls setting value, recover definite value with reference to voltage after the fault in the low pressure load shedding control device at present both at home and abroad commonly used, this value is taken as 0.25～0.3pu), then at the F of this subarea cooperation layer _S=1;

2. if the electric voltage dropping index of cooperation layer d place, subarea child partition electrical network less than Δ U _Acc(Δ U _AccBe the voltage permissible variation, with reference to the voltage permissible variation after " power system voltage and var technology guide rule " accident, this value is taken as 0.1～0.15pu), then at the F of this subarea cooperation layer _S=-1;

3. under other situation, the F of subarea cooperation layer d correspondence _S=0;

To the low frequency load shedding control of a plurality of child partitions, F _SThe assignment principle is as described in the 2.4.5:

2.4.5 if the cooperation layer frequency uploaded in subarea is fallen maximum difference between index less than f _Err1(f _Err1For the subarea frequency is fallen poor setting value, with reference to the frequency action setting value of adjacent two-wheeled in traditional low frequency load shedding control Typical Disposition scheme, this value is taken as 0.2Hz), at the subarea off-load accelerator coefficient F of each subarea cooperation layer _SBe 0; Otherwise:

1. frequency is fallen the child partition electrical network of index maximum, the F of its subarea cooperation layer correspondence _S=1;

2. frequency is fallen the child partition electrical network of index minimum, if frequency is fallen index and is not more than Δ f _Acc(Δ f _AccBe the frequency permissible variation, representative value is 1.0Hz, and promptly frequency is not less than 49.0Hz), the F of its subarea cooperation layer correspondence then _S=-1;

3. the F of other subarea cooperation layer correspondence _S=0.

2.5, subarea cooperation layer d increases the weight of coefficient F with local off-load _LThe electrical network at this subarea cooperation layer that issues with the whole network cooperation layer is subjected to electrical power bust index F _w, subarea off-load accelerator coefficient F _SReal time down is given each local cooperation layer in the child partition electrical network of place in the lump.

2.6, local cooperation layer c.d receives the F that subarea cooperation layer d issues _w, F _SAnd F _L, and fall with average frequency according to the average voltage of each situ reaction layer in the partial-block electrical network of place and to fall the dynamic order result, the conversion zone off-load that execution in step 2.6.1～2.6.3 calculates at situ reaction layer r.c.d increases the weight of COEFFICIENT K _A.rWith conversion zone off-load round quick-action index N _A.r, and with F _w, K _A.rAnd N _A.rBe issued to situ reaction layer r.c.d.

2.6.1 the conversion zone off-load of situ reaction layer r.c.d correspondence increases the weight of COEFFICIENT K _A.rWith conversion zone off-load round quick-action index N _A.rAll be initialized as 0;

2.6.2 if F _w＞K _UC, N _A.rBe changed to ∞, no longer calculating K _A.rIf K _OC≤ F _w≤ K _UCNo matter, subarea off-load accelerator coefficient F _SValue how, N _A.r=1; If F _w＜K _OC, N _A.r=F _S

2.6.3 as if the conversion zone off-load round quick-action index N that calculates according to step 2.6.2 _A.r=0 or N _A.r=1, utilize formula (6) calculating K _A.r

$K_{a.r}=\left\{\begin{array}{cc}{F}_L+0.1\&CenterDot;\frac{(\mathrm{RMAX}.c.d-r+1)}{\mathrm{RMAX}.c.d}& F_L\&GreaterEqual;0\\ F_L-0.1\&CenterDot;\frac{r}{\mathrm{RMAX}.c.d}& F_L<0\end{array}\right.---\left(6\right)$

Wherein:

A) K _UCFor owing to control coefficient, but consider the stand-by heat of electrical network own and install the special cutting load amount of taking turns that it is worth greater than 1; K _OCFor crossing the control coefficient, it is worth less than 1;

B) r (order when 1≤r≤RMAX.c.d) falls the descending ordering of (or average frequency falls) dynamic order table for situ reaction layer r.c.d at average voltage.

2.7 situ reaction layer r.c.d receives the electrical network that local cooperation layer c.d issues in real time and is subjected to electrical power bust index F _w, the conversion zone off-load increases the weight of COEFFICIENT K _A.rWith conversion zone off-load round quick-action index N _A.r, utilize formula (7) to calculate the load shedding amount of current time respective action round, omit time index t in the formula.Receive above-mentioned information if this fails constantly, the load shedding amount of action round kept a last moment to be worth constant.

$P_{\mathrm{now}.r}^{\&prime;}=\left\{\begin{array}{cc}0& N_{a.r}=-1\\ (1+K_{a.r})\&CenterDot;F_w\&CenterDot;P_{\mathrm{now}.r}& N_{a.r}=0\\ (1+K_{a.r})\&CenterDot;F_w\&CenterDot;P_{\mathrm{now}.r}+P_{\mathrm{next}.r}& N_{a.r}=1\\ P_{\mathrm{all}.r}& N_{a.r}>1\end{array}\right.---\left(7\right)$

Wherein, P _Now.rLoad shedding amount (or ratio) for action round now.r setting under the initial scheme; P _Next.rLoad shedding amount (or ratio) for round next.r (next.r=now.r+1) setting under the initial scheme; P _All.rFor under the initial scheme action round now.r and follow-up all take turns the load shedding total amount (or ratio) of setting; P ' _Now.rBe the action round now.r load shedding amount (or ratio) after upgrading.

Among the present invention, disclosed and a kind ofly can in real-time control algolithm, take into account in the dynamic process difference of disturbed degree between the different nodes of electrical network, and changed the low-frequency and low-voltage load-reducing control method of automatic regulating equipment action round load shedding amount according to actual condition.This method makes up a layered distribution type multi-agent system that comprises situ reaction layer, local cooperation layer, subarea cooperation layer and the whole network cooperation layer in electrical network, by the information interaction between each layer proxy, know that system under the actual condition gone into power and interruptable power after disturbed; By the metrical information of electrical network medium and low frequency low pressure load shedding control device is carried out analytical integration, determine the difference of zones of different or the disturbed degree of node, in disturbed serious zone or node quicken or increase the weight of control, and in disturbed relatively lighter zone or node cancellation or alleviate control, the load shedding control of utilization varianceization improves the cost performance of control device.The method of utilizing this invention to propose has overcome the problem that traditional low-frequency and low-voltage load-reducing scheme can't be adjusted with changes of operating modes, and by the most effective control point, location automatically, adjust the load shedding controlled quentity controlled variable, further reduced load shedding control cost.

Description of drawings

Fig. 1 is process 1 flow chart of the present invention;

Fig. 2 is process 2 flow charts of the present invention;

Fig. 3 is certain actual receiving end electrical network 500kV grid structure figure;

Fig. 4 is and the corresponding multi-agent system structure chart of actual receiving end electrical network shown in Figure 3.

Embodiment

Be example with certain actual receiving end electrical network below, investigate the validity of this method, and, the inventive method is described in detail in conjunction with Fig. 1 and Fig. 2.

The 500kV main grid structure structure of certain actual receiving end electrical network has been omitted among the figure as shown in Figure 3 by off line 220kV and the 110kV load bus of each 500kV main transformer.Electrical network links to each other with major network by the section of being gone into that 6 500kV circuits constitute, and is gone into the about 6784MW of power from major network.

At the situation of layouting of automatic low-frequency low-voltage load shedding control device in topological structure of electric and the electrical network, it is divided into three child partition electrical networks, wherein child partition 1 is made up of 3 partial-block; Child partition 2 and child partition 3 are made up of 2 partial-block respectively, and corresponding multi-agent system as shown in Figure 4.

Fig. 1 has mainly described the behavior of process 1 in the inventive method, comprises the steps:

According to step 1 among Fig. 1, but the voltage of each situ reaction layer real-time measurement apparatus installation place bus, frequency and device reality cutting load amount information.According to measurement result, the situ reaction layer can judge whether voltage fluctuation of current time this locality and frequency fluctuation move in the deviation range that is allowed normal, if, judge that the operation of current time system is normal, voltage and frequency be safety all, but only need updating device reality cutting load amount to mate current operating condition; Otherwise, illustrate that current time voltage or frequency are dangerous, carry out next step.

Under certain catastrophe failure, gone into 6 500kV circuits of section and disconnected in succession, the lonely network operation of electrical network.According to step 2 among Fig. 1, device detect voltage or frequency when dangerous judgment means whether satisfy barring condition, when satisfying barring condition, will install reliable locking and return step 1, wait the quantity of state information in next moment to be measured; Behind the device unlocking, execution in step 3.

According to step 3 among Fig. 1, device measures judgment means by this ground voltage or frequency and whether satisfies operation condition, if the then corresponding round action of trigger equipment; Otherwise, show that device does not satisfy operation condition, return step 1 and wait for next measurement and judgement constantly.

If certain all round of situ reaction layer corresponding intrument is all moved, illustrate that this device can't continue excision load from electrical network in the subsequent dynamic process, finish the control of this device; Otherwise, return next measurement and judgement constantly of step 1 beginning.

Fig. 2 has mainly described the behavior of process 2 in the inventive method, comprises the steps:

According to step 1 among Fig. 2, each situ reaction layer calculates in real time average voltage and falls with average frequency and fall behind the device unlocking, but and its value and device reality cutting load amount is uploaded in the lump the local cooperation layer of affiliated partial-block.

According to step 2 among Fig. 2, but each local cooperation layer is uploaded to the partial-block cutting load amount of statistics the subarea cooperation layer of affiliated child partition electrical network on the one hand; On the other hand, the average voltage that local cooperation layer is uploaded each situ reaction layer in the partial-block electrical network of place falls to fall with average frequency and carries out dynamic order respectively, calculate the electric voltage dropping index and the frequency of this local cooperation layer place partial-block electrical network according to ranking results and fall index, and its value is uploaded to the subarea cooperation layer of affiliated child partition.

According to step 3 among Fig. 2, but the partial-block cutting load amount that each subarea cooperation layer is uploaded all local cooperation layers in the child partition electrical network of place is added up, but obtain child partition cutting load amount, and measure the power that place child partition electrical network is gone into from major network, but and will be gone into power and child partition cutting load amount is uploaded to the whole network cooperation layer; Simultaneously, the subarea cooperation layer falls index dynamic order result according to the electric voltage dropping index and the frequency of each partial-block electrical network, calculates the electric voltage dropping index and the frequency of place child partition electrical network and falls index, and its value is uploaded to the whole network cooperation layer; Calculating increases the weight of coefficient F at the local off-load of each local cooperation layer in the child partition electrical network of place _L

According to step 4 among Fig. 2, but the whole network cooperation layer is gone into power and child partition cutting load amount according to what each child partition was uploaded, obtain that but the current time electrical network is actual is gone into power total amount and electrical network reality cutting load total amount, the electrical network that calculates at each subarea cooperation layer is subjected to electrical power bust index F _w, at actual receiving end electrical network shown in Figure 3, the about 23713MW of electrical network internal loading total amount, but initial load shedding scheme lower device cutting load amount adds up to 14687MW, calculates F _wBe about 0.46; Simultaneously, fall index dynamic order result, calculate subarea off-load accelerator coefficient F at each subarea cooperation layer according to the electric voltage dropping index and the frequency of each child partition electrical network _S, and electrical network is subjected to electrical power bust index F _wWith subarea off-load accelerator coefficient F _SBe issued to each subarea cooperation layer.

According to step 5 among Fig. 2, the local off-load that the subarea cooperation layer will generate increases the weight of coefficient F _LAnd the electrical network that the whole network cooperation layer issues is subjected to electrical power bust index F _wWith subarea off-load accelerator coefficient F _SBe issued to each local cooperation layer in the child partition electrical network of place.

According to step 6 among Fig. 2, the electrical network that local cooperation layer reception subarea cooperation layer issues is subjected to electrical power bust index F _w, subarea off-load accelerator coefficient F _SAnd local off-load increases the weight of coefficient F _LAnd fall with average frequency in conjunction with the average voltage of each situ reaction layer in the partial-block electrical network of place and to fall the dynamic order result, calculating increases the weight of coefficient and conversion zone off-load round quick-action index at the conversion zone off-load of each situ reaction layer in the partial-block electrical network of place, and is subjected to electrical power bust index, conversion zone off-load to increase the weight of coefficient the electrical network and conversion zone off-load round quick-action index is issued to each situ reaction layer.

According to step 7 among Fig. 2, the situ reaction layer receives the electrical network that cooperation layer issues and is subjected to electrical power bust index, conversion zone off-load to increase the weight of coefficient and conversion zone off-load round quick-action indication information, if receives successfully then upgrade current time and move the load shedding amount of round; Otherwise the load shedding amount of action round kept a last moment to be worth constant.Under the normal situation of communication, the method that adopts the present invention to propose, only excision load 2890MW is that restorable system voltage, frequency are to acceptable level.Compare with traditional low-frequency and low-voltage load-reducing control method, reduce cutting load and reach 3000MW, reduce load shedding control cost greatly.

In a word, the present invention is by making up the multi-agent system of a layered distribution type in electrical network, and utilize information interaction between each layer proxy, taken into account the difference of disturbed degree between Disturbed Power Systems zones of different or node fully, and on initial load shedding control strategy, adjusted with this; But gone into the electrical network integral body cutting load amount of power and arrangement according to electrical network under the actual condition, when disturbance causes more high-power vacancy, quicken one and take turns or severally take turns load shedding control.The method that adopts the present invention to propose can reduce load shedding control cost in recovery system voltage, frequency on the one hand to the prerequisite of acceptable level, make the variation of adaptive system operating condition preferably of load shedding controlling schemes on the other hand.

Claims (7)

1. The low-frequency and low-voltage load shedding control method based on multi-agent technology is characterized in that: Combined with the grid topology and the actual distribution of low-frequency and low-voltage load shedding control devices, the grid is divided into one or several sub-sections, and each sub-section is divided into several local sub-sections; in each sub-section, a hub substation is selected to be set as a multi-agent system. Sub-area coordination layer, if there are multiple sub-area coordination layers in the power grid, select a sub-area coordination layer as the network-wide coordination layer of the multi-agent system; select a hub substation in each local area to set it as the local coordination layer of the multi-agent system ; The low-frequency and low-voltage load shedding control device in the power grid is set as the local response layer of the multi-agent system; the local response layer, local coordination layer, sub-region coordination layer and whole network coordination layer constitute a layered distributed multi-agent system. The ground response layer only establishes a communication link with the local coordination layer of its local division; the local coordination layer only establishes a communication relationship with the sub-region coordination layer of its sub-division; the sub-region coordination layer only establishes a communication relationship with the whole network coordination layer; Among them, two processes are carried out at the same time: Process 1: According to the real-time measured voltage and frequency information of the bus bar where the device is installed, the on-site response layer triggers the action of the device when it is determined that the device meets the action conditions, and performs load shedding control; at the same time, the on-site response layer also makes real-time statistics of The actual load shedding capacity of the device; Process 2 includes the following steps: 1) The local response layer uploads the local state quantity information and the actual shedding load of the device under the current working condition to the local coordination layer of the local partition to which it belongs; 2) The local coordination layer analyzes the information uploaded by the local response layer, and uploads the frequency and voltage dynamic analysis results of the local sub-region grid where the local coordination layer is located and the load shedding capacity of the local sub-region to the sub-region coordination layer of the sub-region to which it belongs; 3) The sub-area coordination layer calculates the local load shedding and aggravation coefficients for each local coordination layer in the sub-area grid, and uploads the frequency and voltage dynamic analysis results of the sub-area grid, as well as the power received by the sub-area grid from the main grid and the sub-area’s available power. Load shedding to the coordination layer of the whole network; 4) The coordination layer of the whole network summarizes the information uploaded by the coordination layer of each sub-area, calculates the power grid receiving power sudden drop index and the acceleration coefficient of sub-area load reduction for each sub-area coordination layer, and sends them to the coordination layer of each sub-area; 5) The sudden drop index of power received by the power grid under the sub-area coordination layer, the sub-area load shedding acceleration coefficient and the local load shedding aggravation factor are sent to each local coordination layer in the sub-district power grid; 6) The local coordination layer calculates the reaction layer load shedding aggravation coefficient and the reaction layer load shedding round quick index for each in-situ reaction layer in the local regional power grid, and calculates the sudden drop index of the power grid received power and the reaction layer load shedding aggravation coefficient The quick index of load shedding rounds at the response layer is issued to each local response layer in the local sub-regional power grid; 7) The on-site response layer receives the sudden drop index of power grid power received from the local coordination layer, the load reduction aggravation coefficient of the response layer, and the quick index of the load reduction round of the reaction layer, and updates the load reduction amount of the action round. 2. the low-frequency and low-pressure load-shedding control method based on multi-agent technology according to claim 1, is characterized in that, constructs a system comprising an in-situ response layer, a local coordination layer, a sub-area coordination layer and a whole network coordination layer in the power grid Hierarchical distributed multi-agent system. 3. The low-frequency low-voltage load shedding control method based on multi-agent technology according to claim 1, characterized in that, process 1 and process 2 are two processes carried out simultaneously. 4. the low-frequency low-voltage load-shedding control method based on multi-agent technology according to claim 2 is characterized in that in the process 1, in addition to the voltage and the frequency of the real-time measurement device installation place busbar, the in-situ reaction layer also needs to count the current work The actual load shedding capacity of the device under the condition. 5. The low-frequency low-voltage load-shedding control method based on multi-agent technology according to claim 1, characterized in that in the step 1) of the described process 2, the local response layer does not directly upload the voltage and frequency measurements to the The local coordination layer calculates the average voltage drop based on the voltage measurement, calculates the average frequency drop based on the frequency measurement, and uploads the average voltage drop and the average frequency drop to the local coordination layer of the local partition. 6. the low-frequency low-voltage load reduction control method based on multi-agent technology according to claim 1, is characterized in that in the step 4) of described process 2, the whole network coordination layer summarizes each sub-area coordination layer upload information, obtains current work According to the actual total power received by the power grid and the total load that can be shed by the power grid, calculate the sudden drop index of power received by the power grid for each sub-area coordination layer; use the voltage drop index and frequency drop index of the sub-area grid where the coordination layer of each sub-area is located Dynamically sort the results, and calculate the sub-area load-shedding acceleration coefficient for each sub-area coordination layer. 7. The low-frequency low-voltage load-shedding control method based on multi-agent technology according to claim 1, wherein if at a certain moment, the local response layer successfully receives the power grid received power sudden drop index issued by the local coordination layer, the response layer reduces If the loading coefficient and the quick movement index information of the load reduction round of the reaction layer are updated, the load reduction amount corresponding to the action round at that moment will be updated, and when the local voltage or frequency measurement is used to determine that the device meets the operating conditions, the updated load reduction value will be used. Implement the load reduction control of this round; if the local response layer fails to receive the above information from the local coordination layer at this moment, the load reduction amount of the action round will remain unchanged from the previous time value, and will not affect the operation of the device.

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