CN103986165B - Refining load control method and system in electric system - Google Patents

Abstract

The invention provides a refining load control method in an electric system. The method comprises the steps that a control center detects a load capacity needing to be adjusted by a user group at present; the control center obtains the standby capacity of a power utilization device in a user terminal and the preset load regulating and controlling level; the control center calculates the adjustable and controllable load of different load regulating and controlling levels in the user group according to the standby capacity of the power utilization device and the preset load regulating and controlling level; the control center generates and sends a load regulating and controlling signal to the user terminal according to the load capacity needing to be adjusted by the user group at present and the adjustable and controllable loads of the different load regulating and controlling levels of the user group, wherein the load regulating and controlling comprises the current regulating and controlling level and the regulating and controlling proportion; the user terminal receives the load regulating and controlling signal, and the load of the power utilization device is adjusted according to the current load regulating and controlling level and the regulating and controlling proportion. The invention further provides a corresponding system. The processing burden of the electric system can be greatly reduced, and the load regulating and controlling speed is improved.

Description

Load Precise control method and system in power system

Technical field

The present invention relates to power system computation field, particularly relate to a kind of load Precise control method in power system, and load Precise control system in a kind of power system.

Background technology

When wholesale power market price raises or system reliability is compromised, after power consumer receives the direct compensation notice or power price rising signals that inductivity that supplier of electricity sends reduces load, the custom power mode that it is intrinsic need be changed, reach and reduce or pass the power load of certain period and respond supply of electric power, thus the guarantee stabilization of power grids, and electricity price is suppressed to rise.

It is predicted, about the year two thousand twenty Analyzing Total Electricity Consumption will reach 7.7 trillion kilowatt hours, peak load will reach 12.7 hundred million kilowatts.If power supply can implement the load control of effect, then at least can realize economize on electricity 5% and reduce peak load 5%, at least can reduce electric power to the year two thousand twenty and install 1.3 hundred million kilowatts, Generation Side average load rate at least improves about 4 percentage points, gross coal consumption rate 8.4 grams/kilowatt hour can be reduced, thus standard coal can be saved every year be about fifty-five million ton; Electricity consumption side power consumption efficiency improves 5 percentage points, then generated energy about 4,000 hundred million kilowatt hour can be lacked in the whole nation when the time comes, is equivalent to reduce by about 1.3 hundred million tons of standard coal consumption in.Therefore visible, supplier of electricity implements load control by the very considerable energy-saving and emission-reduction of generation and social benefit to power consumer.

Conventional art can divide incident classification the ratio causing electrical network to subtract for load usually.Such as, for the province of load more than 2,000 ten thousand kilowatts, autonomous region's electrical network, subtract for load less than more than 13% 30%, then form major accident; Subtract for load more than 30%, then form special major accident.At present, China's single extra-high voltage alternating current-direct current power transmission engineering transmission capacity is comparatively large, and such as, the specified transmission power of bright and beautiful Su Zhiliu reaches 7,200,000 kilowatts, and Changzhi-Nanyang-Jingmen specified transmission power of extra-high-voltage alternating current demonstration project reaches 5,000,000 kilowatts.Before extra-high voltage alternating current-direct current transmission of electricity forms network structure, after single UHV transmission channel failure, amphidromic stream transfering channel, causes greater impact to two ends electrical network, unavoidably causes the machine of cutting of larger proportion, the consequence of cutting load.

At present, because power consumer quantity is very huge, amount of calculation and the processing load of power system load regulation and control are very large, and processing speed is slow, the cutting load device of electric power system stability control system is generally arranged on 110kV and above transformer station, draws and stop outlet switch during cutting load, has the feature of " a black a slice ", the mode of load control belongs to extensive, cannot satisfy the demands.

Summary of the invention

Based on this, the invention provides load Precise control method and system in a kind of power system, significantly can reduce the processing load of power system, improve load control speed.

A kind of load Precise control method in power system, comprises the steps:

The load that active user group need adjust detects in control centre; Wherein, described customer group comprises multiple user side, and described user side comprises multiple stage electrical appliance;

The spare capacity that control centre obtains electrical appliance described in described user side and the load control rank preset;

Control centre, according to the spare capacity of described electrical appliance and described load control rank, calculates the controllable load of different load regulation and control rank in described customer group;

In the load that control centre need adjust according to described active user group and described customer group, the controllable load of different load regulation and control rank, generates load control signal and also sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

Described user side receives described load control signal, adjusts the load of described electrical appliance according to this load control rank described and regulation and control ratio.

Load Precise control system in a kind of power system, comprise control centre and customer group, described customer group comprises multiple user side, and described user side comprises multiple stage electrical appliance:

Described control centre comprises detection module, for detecting the load that active user group need adjust;

Described control centre comprises acquisition module, for obtaining the spare capacity of electrical appliance described in described user side and default load control rank;

Described control centre comprises computing module, for according to the spare capacity of electrical appliance described in described user side and the load control rank preset, calculates the controllable load of described customer group different load regulation and control rank;

Described control centre comprises sending module, for the controllable load according to different load regulation and control rank in the load needing in described active user group to adjust and described customer group, generates load control signal and sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

Described user side, for receiving described load control signal, adjusts the load of described electrical appliance according to this load control rank described and regulation and control ratio.

Load Precise control method and system in above-mentioned power system, the load that active user group need adjust detects in control centre, and the spare capacity obtaining electrical appliance described in user side and the load control rank preset, calculate the controllable load of different load regulation and control rank in customer group, then regeneration load control signal is broadcast to each user side; User side then adjusts the load of described electrical appliance according to this load control rank in load control signal and regulation and control ratio; Thus significantly reducing the amount of calculation of control centre, the present invention is easy to expansion, is a kind of load control method of non-intrusion type, and the compatible multiple electrical appliance of energy, can realize the regulation and control that become more meticulous of load.

Accompanying drawing explanation

Fig. 1 is load Precise control method schematic flow sheet in one embodiment in power system of the present invention.

Fig. 2 is the schematic diagram of load Precise control method load control signal in one embodiment in power system of the present invention.

Fig. 3 is the load Precise control method schematic diagram of the electrical appliance that different load regulation and control rank is corresponding in user side in one embodiment in power system of the present invention.

Fig. 4 is load Precise control system structural representation in one embodiment in power system of the present invention.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

As shown in Figure 1, be the schematic flow sheet of load Precise control method in power system of the present invention, comprise the steps:

S11, control centre detect the load that active user group need adjust; Wherein, described customer group comprises multiple user side, and described user side comprises multiple stage electrical appliance;

S12, control centre obtain the spare capacity of electrical appliance described in described user side and default load control rank;

S13, control centre, according to the spare capacity of described electrical appliance and described load control rank, calculate the controllable load of different load regulation and control rank in described customer group;

In the load that S14, control centre need adjust according to described active user group and described customer group, the controllable load of different load regulation and control rank, generates load control signal and also sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

S15, described user side receive described load control signal, adjust the load of described electrical appliance according to this load control rank described and regulation and control ratio;

In the present embodiment, first control centre obtains the load that active user group need regulate and control; Described customer group comprises the multiple user sides be connected with control centre, and each user side connects multiple stage electrical appliance, and electrical appliance can comprise air-conditioning, desk lamp, water dispenser, TV, charger etc.

Control centre also from each user side obtain connect each user side each described in the spare capacity of electrical appliance and the load control rank preset corresponding to described electrical appliance;

The load control rank of the present embodiment can be used for distinguishing the state of current electric grid and the participation of electrical equipment participation load control, thus makes: the electrical equipment 1) being applicable to participating in load control, first participates in load control, run with making the less energy consumption of electrical network; 2) be not suitable for long-term but can the short time, a small amount of electrical equipment participating in load control, only participate in response when electrical network is badly in need of reducing load, thus ensure power grid security, stable operation.The load control rank of user side by presetting, allows electrical equipment to participate in load control with the different degree of depth, makes participation form more flexible.

Such as, load control rank can comprise 4 ranks as shown in the table, also can expand on this basis according to actual needs:

The hierarchical relationship of relative size is there is between load control rank, the relation of 4 ranks described in upper table never participates in for the < of participation < peak load participation at any time promptly participates in <, each rank has corresponding level identification, be followed successively by 0,1,2, N/A; " never participate in " rank owing to not participating in load control, therefore the present embodiment is follow-up can not consider when adding up load.

Next, control centre is according to the spare capacity of described electrical appliance and described load control rank, the controllable load of different load regulation and control rank in customer group described in statistical computation, afterwards again in conjunction with the load that described active user group need adjust, generate load control signal and send to described user side;

Control centre receives the spare capacity of its each electrical appliance prestored that each user side sends and load control rank corresponding to this default electrical appliance and adds up, thus obtain total spare capacity corresponding to whole customer group different load regulation and control rank, then generate load control signal according to following methods:

Make l=l ₀, $Q=Q_d^{\left(1\right)};$

Wherein, l ₀for minimum load control rank, for the controllable load that load control rank l is corresponding;

If Q>=Δ Q _t, then determine that this regulation and control rank described is l;

If Q < Δ Q _t, then make l=l+1, if l is rank maximum in load control rank, then determine that this regulation and control rank described is l;

Wherein, l=l+1 represents increases a rank by current load control rank; Δ Q _tfor the load that described active user group need adjust;

After determining this regulation and control rank, regulation and control ratio can be calculated further; In the load that need be able to adjust according to described active user group, described customer group, different load regulates and controls the controllable load of rank and this regulation and control rank described, is calculated by following formula:

$r_{\mathrm{signal}}=\frac{{\mathrm{\&Delta;Q}}_t-\underset{l=1}{\overset{l_{\mathrm{signal}}-1}{\mathrm{\&Sigma;}}}{Q}_d^{\left(l\right)}}{Q_d^{\left(l_{\mathrm{signal}}\right)}};$

Wherein, r _signalfor described regulation and control ratio, l _signalfor this regulation and control rank described, l _signalcurrent load control rank is reduced by a rank by-1 expression.

Load control signal comprises this load control rank and regulation and control ratio two data; The generation of load control signal, by reasonable distribution, can reduce the size of load control signal, thus improves the efficiency issuing load control signal, reduces the workload to a large number of users end broadcast load control signal.

In the present embodiment, load control signal can use this load control rank of 2 byte representations and regulation and control ratio, and in the present embodiment, load control rank can comprise 3 grades, utilizes 4 binary systems to represent [0,7] integer in interval, is enough to represent load control rank; Remaining 12 for recording regulation and control ratio, expression scope is the regulation and control ratio of 0 ~ 212-1; Therefore, regulation and control ratio also needs to carry out sliding-model control, is calculated by following formula:

k＝round((2 ⁿ-1)×r _signal)；

Wherein, k is the regulation and control ratio after described sliding-model control, and n is default number of bits.

Such as, when control centre is according to the instruction of supplier of electricity, detect when need reduce 10000W load, according to statistical computation, obtain 3 load control ranks in customer group: participation level (0) corresponding spare capacity is 8502W at any time, peak load participation level (1) corresponding spare capacity is 10220W, and urgent participation level (2) corresponding spare capacity is 7018W;

Then this regulation and control rank is determined:

(1) l=0 is established,

(2) if Q>=Δ Q _t, then perform step (4), otherwise continue to perform step (3).

(3) l=l+1, return step (2); If l overloads, the maximum of regulation and control rank, then direct by l _signal=l exports.

(4) these regulation and control rank l is determined _signal=l;

After determining this regulation and control rank, calculate regulation and control ratio further; Calculate by following formula:

$r_{\mathrm{signal}}=\frac{{\mathrm{\&Delta;Q}}_t-\underset{l=1}{\overset{l_{\mathrm{signal}}-1}{\mathrm{\&Sigma;}}}{Q}_d^{\left(l\right)}}{Q_d^{\left(l_{\mathrm{signal}}\right)}};$

According to above-mentioned steps, this regulation and control rank in the present embodiment is:

l _signal＝1

$r_{\mathrm{signal}}=\frac{\mathrm{\&Delta;}{Q}_t-Q_d^{\left(0\right)}}{Q_d^{\left(1\right)}}=\frac{10000-8502}{10220}=0.1465753425$

After will regulating and controlling inverse discrete, can obtain:

$k=\mathrm{round}((2^n-1)\&times;\frac{10000-8502}{10220})=600$

According to the load control signal format of the present embodiment, the load control signal of generation can be as shown in Figure 2.

User side receives described load control signal, reads out this regulation and control rank and regulation and control ratio, carry out load control to each electrical appliance from described load control signal; As shown in Figure 3, be the schematic diagram that in user side, different load regulates and controls electrical appliance corresponding to rank;

Because regulation and control ratio is through sliding-model control, the regulation and control ratio of sliding-model control need be normalized by user side:

$r_{\mathrm{signal}}=\frac{k}{2^n-1}=\frac{k}{2^{12}-1}=2.441\&times;{10}^{-4}k,k=\mathrm{0,1},...,4095.$

Concrete, the step how user side regulates and controls each electrical appliance according to described load control signal is as follows:

User side receives load control signal (l _signal, r _signal) after, all default regulating strategies being superior to this load control rank all can not perform, and all default regulating strategies lower than this load control rank all can perform, the strategy that grade is just equal with this load control rank, can according to r _signalwith specific strategy consequence, optionally perform, load control signal is a positive integer, r _signal∈ [0,4095].

User side carries out load control according to load control signal, and load control process is specific as follows:

Each user side obtains the spare capacity of each electrical equipment under each load control rank:

$Q_{\mathrm{id}}^{\left(l\right)}=\left\{\begin{array}{cc}{Q}_{\mathrm{is}}^{\left(l\right)},& l=0\\ \max \{Q_{\mathrm{is}}^{\left(l\right)}-Q_{\mathrm{is}}^{(l-1)},0\},& l>0\end{array}\right\};$

Wherein, l is described load control rank, and i is described electrical appliance, for the actual spare capacity of electrical appliance i under load control rank l, for the maximum spare capacity of electrical appliance i under load control rank l;

Each user side obtains the summation of the spare capacity of each electrical appliance under each load control rank, generates total spare capacity of each load control rank; Each user side receives load control signal, and according to the total spare capacity under the load control signal received and each load control rank, obtains the load control strategy of the power consumption of electrical appliance corresponding to each user side of regulation and control; According to described load control strategy, what regulate and control electrical equipment corresponding to each user side uses electricity condition;

User side receives load control signal, and electricity condition of using corresponding for the load control rank lower than described load class is used electricity condition as pending; According to total spare capacity of described regulation and control ratio and the load control rank identical with described load class, generate the load control strategy corresponding with described load class, concrete according to the spare capacity in load control signal, regulation and control ratio and can to solve as drag, obtain the xj of each electricity condition, generate the load control strategy corresponding with described load class:

$\begin{array}{cc}\max & {\mathrm{\&Delta;Q}}_d^{\left(l_{\mathrm{signal}}\right)}=\underset{j=1}{\overset{m}{\mathrm{\&Sigma;}}}{\mathrm{\&Delta;Q}}_{\mathrm{js}}^{\left(l_{\mathrm{signal}}\right)}{x}_j\end{array}$

$\begin{array}{cc}s.t.& {\mathrm{\&Delta;Q}}_d^{\left(l_{\mathrm{signal}}\right)}\&le;r_{\mathrm{signal}}\&CenterDot;{Q_d}^{\left(l_{\mathrm{signal}}\right)}\\ & \underset{j\&Element;S_i}{\mathrm{\&Sigma;}}{x}_j\&Element;\left\{\mathrm{0,1}\right\}\\ & x_j\&Element;\left\{\mathrm{0,1}\right\}\end{array}$

Wherein, j is for using electricity condition, l _signalfor this load control rank described, γ _signalfor the regulation and control ratio in described load control signal, for the total amount of the spare capacity of each electrical appliance after regulation and control, for with electricity condition j at described load class l _signalunder spare capacity, for the total spare capacity under the load control rank identical with described load class, x _jfor performing mark, S for identifying whether with electricity condition j _ifor the electricity consumption state set of electrical appliance i.

As shown in Figure 4, be the structural representation of load Precise control system in a kind of power system of the present invention, comprise control centre 41 and customer group 42, described customer group comprises multiple user side 421, and described user side comprises multiple stage electrical appliance:

Described control centre comprises detection module 411, for detecting the load that active user group need adjust;

Described control centre comprises acquisition module 412, for obtaining the spare capacity of electrical appliance described in described user side and default load control rank;

Described control centre comprises computing module 413, for according to the spare capacity of electrical appliance described in described user side and the load control rank preset, calculates the controllable load of different load regulation and control rank in described customer group;

Described control centre comprises sending module 414, for the controllable load of the load that need adjust according to described active user group and described customer group different load regulation and control rank, generates load control signal and also sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

Described user side 421, for receiving described load control signal, adjusts the load of described electrical appliance according to this load control rank described and regulation and control ratio;

In the present embodiment, first control centre obtains the load that active user group need regulate and control; Described customer group comprises the multiple user sides be connected with control centre, and each user side connects multiple stage electrical appliance, and electrical appliance can comprise air-conditioning, desk lamp, water dispenser, TV, charger etc.

Control centre also from each user side obtain connect each user side each described in the spare capacity of electrical appliance and the load control rank preset corresponding to described electrical appliance;

The load control rank of the present embodiment can be used for distinguishing the state of current electric grid and the participation of electrical equipment participation load control, thus makes: the electrical equipment 1) being applicable to participating in load control, first participates in load control, run with making the less energy consumption of electrical network; 2) be not suitable for long-term but can the short time, a small amount of electrical equipment participating in load control, only participate in response when electrical network is badly in need of reducing load, thus ensure power grid security, stable operation.The load control rank of user side by presetting, allows electrical equipment to participate in load control with the different degree of depth, makes participation form more flexible.

Such as, load control rank can comprise 4 ranks as shown in the table, also can expand on this basis according to actual needs:

There is the hierarchical relationship of relative size between load control rank, the relation of 4 ranks described in upper table never participates in for the < of participation < peak load participation at any time promptly participates in <; Never participation level is not owing to participating in load control, and therefore the present embodiment can follow-uply can not considered when adding up load.

Next, control centre is according to the spare capacity of described electrical appliance and described load control rank, the controllable load of customer group different load regulation and control rank described in statistical computation, afterwards again in conjunction with the load that described active user group need adjust, generate load control signal and send to described user side;

Control centre receives the spare capacity of its each electrical appliance prestored that each user side sends and load control rank corresponding to this default electrical appliance and adds up, thus obtain total spare capacity corresponding to whole customer group different load regulation and control rank, generate load control signal:

Make l=l ₀, $Q=Q_d^{\left(1\right)};$

Wherein, l ₀for minimum load control rank, for the controllable load that load control rank l is corresponding;

If Q>=Δ Q _t, then determine that this regulation and control rank described is l;

If Q < Δ Q _t, then make l=l+1, if l is rank maximum in load control rank, then determine that this regulation and control rank described is l;

Wherein, l=l+1 represents increases a rank by current load control rank; Δ Q _tfor the load that described active user group need adjust;

After determining this regulation and control rank, calculate regulation and control ratio further; Calculate by following formula:

$r_{\mathrm{signal}}=\frac{{\mathrm{\&Delta;Q}}_t-\underset{l=1}{\overset{l_{\mathrm{signal}}-1}{\mathrm{\&Sigma;}}}{Q}_d^{\left(l\right)}}{Q_d^{\left(l_{\mathrm{signal}}\right)}};$

Wherein, r _signalfor described regulation and control ratio, l _signalfor this regulation and control rank described, l _signalcurrent load control rank is reduced by a rank by-1 expression.

Load control signal comprises this load control rank and regulation and control ratio two data; The generation of load control signal, by reasonable distribution, can reduce the size of load control signal, thus improves the efficiency issuing load control signal, reduces the workload to a large number of users end broadcast load control signal.

Load control signal can use this load control rank of 2 byte representations and regulation and control ratio, and in the present embodiment, load control rank can comprise 3 grades, utilizes 4 binary systems can represent integer in [0,7] interval, is enough to represent load control rank; Remaining 12 for recording regulation and control ratio, expression scope is the regulation and control ratio of 0 ~ 212-1; Therefore, regulation and control ratio also needs to carry out sliding-model control, is calculated by following formula:

k＝round((2 ⁿ-1)×r _signal)；

Wherein, k is the regulation and control ratio after described sliding-model control, and n is default number of bits.

User side receives described load control signal, reads out this regulation and control rank and regulation and control ratio, carry out load control to each electrical appliance from described load control signal.

Because regulation and control ratio is through sliding-model control, the regulation and control ratio of sliding-model control need be normalized by user side:

$r_{\mathrm{signal}}=\frac{k}{2^n-1}=\frac{k}{2^{12}-1}=2.441\&times;{10}^{-4}k,k=\mathrm{0,1},...,4095.$

Concrete, user side also can be used for:

User side receives load control signal (l _signal, r _signal) after, all default regulating strategies being superior to this load control rank all can not perform, and all default regulating strategies lower than this load control rank all can perform, the strategy that grade is just equal with this load control rank, can according to r _signalwith specific strategy consequence, optionally perform, load control signal is a positive integer, r _signal∈ [0,4095].User side carries out load control according to load control signal.

Load Precise control method and system in power system of the present invention, the load that active user group need adjust detects in control centre, and the spare capacity obtaining electrical appliance described in user side and the load control rank preset, calculate the controllable load of different load regulation and control rank in customer group, then regeneration load control signal is broadcast to each user side; User side then adjusts the load of described electrical appliance according to this load control rank in load control signal and regulation and control ratio; Thus significantly reducing the amount of calculation of control centre, the present invention is easy to expansion, is a kind of load control method of non-intrusion type, and the compatible multiple electrical appliance of energy, can realize the regulation and control that become more meticulous of load.

The above embodiment only have expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims (4)

1. a load Precise control method in power system, is characterized in that, comprise the steps:

The load that active user group need adjust detects in control centre; Wherein, described customer group comprises multiple user side, and described user side comprises multiple stage electrical appliance;

The spare capacity that control centre obtains electrical appliance described in described user side and the load control rank preset;

Control centre, according to the spare capacity of described electrical appliance and described load control rank, calculates the controllable load of different load regulation and control rank in described customer group;

In the load that control centre need adjust according to described active user group and described customer group, the controllable load of different load regulation and control rank, generates load control signal and also sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

Described user side receives described load control signal, adjusts the load of described electrical appliance according to this regulation and control rank described and regulation and control ratio;

Wherein, the controllable load of different load regulation and control rank in the load that described control centre need adjust according to described active user group and described customer group, generates load control signal and also sends to the step of described user side to comprise:

Make l=l ₀, $Q=Q_d^{\left(l\right)};$

Wherein, l ₀for minimum load control rank, for the controllable load that load control rank l is corresponding;

If Q>=Δ Q _t, then determine that this regulation and control rank described is l;

If Q < Δ Q _t, then make l=l+1, if l is rank maximum in load control rank, then determine that this regulation and control rank described is l;

Wherein, l=l+1 represents increases a rank by current load control rank; Δ Q _tfor the load that described active user group need adjust.

2. load Precise control method in power system according to claim 1, it is characterized in that, the controllable load of different load regulation and control rank in the load that described control centre need adjust according to described active user group and described customer group, generates load control signal and also sends to the step of described user side to comprise:

The controllable load of different load regulation and control rank and this regulation and control rank described in the load that need adjust according to described active user group, described customer group, calculate described regulation and control ratio by following formula:

$r_{\mathrm{signal}}=\frac{\mathrm{\&Delta;}{Q}_t-\underset{l=1}{\overset{l_{\mathrm{signal}}-1}{\mathrm{\&Sigma;}}}{Q}_d^{\left(l\right)}}{Q_d^{\left(l_{\mathrm{signal}}\right)}}$

Wherein, r _signalfor described regulation and control ratio, l _signalfor this regulation and control rank described, l _signalcurrent load control rank is reduced by a rank by-1 expression.

3. a load Precise control system in power system, is characterized in that, comprise control centre and customer group, described customer group comprises multiple user side, and described user side comprises multiple stage electrical appliance:

Described control centre comprises detection module, for detecting the load that active user group need adjust;

Described control centre comprises acquisition module, for obtaining the spare capacity of electrical appliance described in described user side and default load control rank;

Described control centre comprises computing module, for according to the spare capacity of electrical appliance described in described user side and the load control rank preset, calculates the controllable load of described customer group different load regulation and control rank;

Described control centre comprises sending module, for the controllable load according to different load regulation and control rank in the load needing in described active user group to adjust and described customer group, generates load control signal and sends to described user side; Wherein, described load control signal comprises this regulation and control rank and regulation and control ratio;

Described user side, for receiving described load control signal, adjusts the load of described electrical appliance according to this regulation and control rank described and regulation and control ratio;

Wherein, described sending module also for:

Make l=l ₀, $Q=Q_d^{\left(l\right)};$

Wherein, l ₀for minimum load control rank, for the controllable load that load control rank l is corresponding;

If Q < Δ Q _t, then make l=l+1, if Q>=Δ Q _t, then determine that this regulation and control rank described is l;

Wherein, l=l+1 represents increases a grade by load control rank; Δ Q _tfor the load that described active user group need adjust.

4. load Precise control system in power system according to claim 3, is characterized in that, described sending module also for:

The controllable load of different load regulation and control rank and this regulation and control rank described in the load that need adjust according to described active user group, described customer group, calculate described regulation and control ratio by following formula:

$r_{\mathrm{signal}}=\frac{\mathrm{\&Delta;}{Q}_t-\underset{l=1}{\overset{l_{\mathrm{signal}}-1}{\mathrm{\&Sigma;}}}{Q}_d^{\left(l\right)}}{Q_d^{\left(l_{\mathrm{signal}}\right)}}$

Wherein, r _signalfor described regulation and control ratio, l _signalfor this regulation and control rank described.