CN103124075A - Reactive power configuration method for wind power base - Google Patents

Abstract

The invention provides a reactive power configuration method for a wind power base. Based on coordination of resources in a system such as adjustable spare capacity and an interruptible load, a reactive power configuration scheme for the wind power base is optimized by the aid of a genetic algorithm by considering various limitations of reactive power optimization of a wind power station and taking the minimum operation risk generated in a dynamic process after dropping of grid-connected point voltage of the wind power station as an optimal object. Compared with a minimum active power network loss configuration scheme frequently used by an existing wind power station, the reactive power configuration method has the advantages that the reactive power configuration capacity of the wind power base can be reduced, the active power spare capacity of the system is reduced, so that the operation cost of the system is reduced, various regulatory resources of the system can be sufficiently invoked, and steady state voltage level and transient voltage characteristics of a grid-connected point can be ensured.

Description

A kind of wind-powered electricity generation base reactive configuration method

Technical field

The present invention relates to a kind of method for the idle configuration in wind-powered electricity generation base, belong to the wind power generation control technology field in the generation of electricity by new energy technology.

Background technology

Access in order to tackle large-scale wind power the immense pressure that causes to electric network reactive compensation configuration and safe and stable operation, State Grid Corporation of China has formulated the specification requirement of " wind energy turbine set access electric power network technique regulation " and the field operation such as " the idle configuration of wind energy turbine set and voltage control technical stipulation " standard grid connected wind power, and clearly propose, the most important requirement of idle configuration of wind energy turbine set is reactive capability and the capability of fast response of wind energy turbine set.

Along with the continuous increase of grid connected wind power installed capacity, the particularly construction in large-scale wind power base, operation has brought series of challenges to power system safety and stability, and line voltage control problem is particularly outstanding.In recent years, in the northwest, a lot of large-scale wind power unit off-grid accidents of occuring of North, Northeast China have all that in system or wind energy turbine set, single failure causes, because the wind-powered electricity generation unit lacks low voltage ride-through capability and reactive power compensation configuration and controls unreasonable, system is formed secondary pulse, cause the expansion of fault coverage.This has exposed the deficiency of Reactive Compensation in Wind Farm configuration and line voltage control aspect existence to a certain extent, therefore, the reactive power compensation configuration in large-scale wind power base and voltage control problem become gradually that wind-powered electricity generation is centralized, one of the key technical problem paid close attention in the great-leap-forward development process.

Present domestic wind-powered electricity generation base reactive configuration method is not perfect, causes the quick response dynamics reactive power compensator of a large amount of installation of system, and the economical operation type is poor.Idle configuration is realized by the algorithm of active power loss minimum in the wind-powered electricity generation base, namely considers the constraints of idle work optimization, and the active power loss minimum that produces in the running of wind-powered electricity generation base is carried out idle configuration as optimization aim.But this algorithm is not considered to break down or disturbed movable property is given birth to after voltage falls when system, may cause large-scale wind power unit off-grid, thereby further cause system reserve to drop into, and even take the cutting load measure, these increase the operating cost of system greatly.

In system, the coordination of the resources such as adjustable standby, interruptible load and reactive power compensator provides condition for the wind-powered electricity generation base reactive configuration method of considering operation risk.

Summary of the invention

Goal of the invention: technical problem to be solved by this invention is the idle allocation problem in wind-powered electricity generation base, and a kind of wind-powered electricity generation base idle work optimization collocation method method that can consider reactive power compensation investment and operating cost, reserve cost and cutting load cost is provided.

The technical solution adopted for the present invention to solve the technical problems is as follows:

A kind of wind-powered electricity generation base reactive configuration method, it comprises the steps:

(1) according to the requirement of wind energy turbine set low voltage crossing technology judgement and site wind turbine group off-grid whether, wind-powered electricity generation set grid-connection point voltage in wind energy turbine set can guarantee not off-grid operation 625ms when dropping to 20% rated voltage, wind farm grid-connected point voltage is when 2s can return to 90% rated voltage after falling, and the wind-powered electricity generation unit can guarantee off-grid operation; If drop to less than 90% rated voltage and within the time that low voltage crossing allows at wind-powered electricity generation set grid-connection point voltage and do not take Measures of Reactive Compensation, can cause wind-powered electricity generation unit off-grid, adopt the optimization method configuration of following step (2)～step (5) and site reactive compensation capacity and active reserve capacity to make the operation risk that falls rear dynamic process minimum.The diversity that breaks down for simulation wind-powered electricity generation base, different voltages are occured in electrical network fall being divided into of amplitude of following nine kinds of scenes, and provide the probability that every kind of scene occurs, ask for respectively that under different scenes, voltage falls issuable maximum operation risk in rear dynamic process, the operation risk desired value after obtaining at last voltage and falling.

2) can be in the hope of the sensitivity relation of wind energy turbine set access point i about self and wind energy turbine set reactive power based on the depression of order Jacobian matrix, and according to both the best access point of level of sensitivity judgement reactive power compensator;

Choosing wind energy turbine set access regional area is research object, if comprise m wind energy turbine set in the zone, and by n the main electrical network of access point access, can obtain only comprising 2 (m+n) exponent part node depression of order Jacobian matrix J of wind energy turbine set node and access point _SI, to J _SIInvert, can get

Can get i access point according to formula (1) about the sensitivity relation of local reactive power is

S ₁=△U _i/△Q _i=a _{2m+n+i,2m+n+i} (2)

Simultaneously, can get i access point about the sensitivity relation of j wind energy turbine set reactive power is

S ₂=△U _i/△Q _j=a _2m+n+i,m+n+j (3)

If S ₁S ₂, carry out the reactive power compensation better effects if in wind energy turbine set access point side; Otherwise, carry out the reactive power compensation effect in the wind energy turbine set exit more excellent.

According to the wind energy turbine set REACTIVE POWER/VOLTAGE sensitivity relation of trying to achieve, can obtain reactive power compensator to the voltage support capacity index of wind farm grid-connected point, N is namely

$\mathrm{\Δ}{U}_j=S_{\mathrm{ji}}\×\underset{i=1}{\mathrm{\Σ}}{Q}_{\mathrm{iSVC}}---\left(4\right)$

Wherein, S _jiFor and the voltage of site j to the sensitivity of node i reactive power compensation, Q _IsvcFor and the reactive compensation capacity of site i;

The dynamic passive compensation Determining capacity should be relevant to the horizontal desired value of the voltage control of each wind energy turbine set access point, therefore, for the scene that various actual motions may occur, the cost of investment R of dynamic passive compensation _SCan be expressed as

$R_S=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{p}_i\×Q_{\mathrm{SVC}}\×k_{\mathrm{SVC}}}{N}---\left(5\right)$

$Q_{\mathrm{SVC}}=\underset{j=1}{\overset{N_W}{\mathrm{\Σ}}}\mathrm{\Δ}{U}_j/S_j---\left(6\right)$

Wherein, p _iProbability for a certain special scenes generation; Q _svcDynamic passive compensation capacity for wind energy turbine set access point configuration under special scenes; The scene number of N for occurring; k _svcBe the idle needed cost of compensation 1Mvar; S _jFor the voltage of access point j about the idle sensitivity in this locality; △ U _jVoltage deviation for access point j; N _WSum for wind energy turbine set in regional power grid;

(3) return to rational scope and can cause wind-powered electricity generation unit off-grid, the active power vacancy that needs the system reserve balance to cause thus if the reactive-load compensation equipment of configuration can do nothing to help wind farm grid-connected point voltage.Be the generation of reply wind-powered electricity generation unit off-grid accident, system will increase a certain proportion of standby on original standby basis.System reserve can be divided into cold standby, substitute standby, stand-by heat and spinning reserve according to response speed, and wherein, the response speed of spinning reserve is the fastest.When system's generation voltage falls when causing wind-powered electricity generation unit off-grid, enable spinning reserve and can effectively alleviate impact on system.Generally, the spinning reserve capacity that configures in system accounts for 5%～10% of system's total load, and operating cost is relatively high; Therefore, the operating cost R of system's reserve _RCan be expressed as:

$R_R=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{p}_i\×P_R\×k_R}{N}---\left(7\right)$

Wherein, P _RActive reserve capacity for regional power grid; k _RCost for configuration 1MW spinning reserve capacity;

(4) ask for according to electric network theory that false voltage under scenario A propagates into and the voltage of site j falls amplitude U _jAAt first, if the system impedance matrix is Z, the promise equivalence that pauses is done by system, obtain the Equivalent admittance battle array Y of system _eqAnd Injection Current

${\stackrel{\·}{I}}_{\mathrm{eq}}^{\left(0\right)}=Y_{\mathrm{eq}}\·{\stackrel{\·}{U}}_{\mathrm{eq}}^{\left(0\right)}---\left(8\right)$

${\stackrel{\·}{U}}_{\mathrm{eq}}^{\left(0\right)}=M_F^T\·{\stackrel{\·}{U}}^{\left(0\right)}---\left(9\right)$

Calculating the non-working port voltage and current is,

${\stackrel{\·}{U}}_F={(I+Z_{\mathrm{eq}}\·Y_F)}^{-1}\·{\stackrel{\·}{U}}_{\mathrm{eq}}^{\left(0\right)}---\left(10\right)$

${\stackrel{\·}{I}}_F=Y_F\·{\stackrel{\·}{U}}_F---\left(11\right)$

False voltage propagates into and the voltage of site j falls amplitude and is,

$U_{\mathrm{jA}}=Z\·M_F{\·\stackrel{\·}{I}}_F---\left(12\right)$

In formula (8)～formula (12),

Be node-port association matrix, Y _FBe the admittance of malfunctioning node ground connection, I is unit matrix;

If it is unreasonable that dynamic passive compensation configuration and system's reserve arrange, in order to guarantee the balance of system's active power, wind-powered electricity generation unit off-grid might cause the cutting load measure, and the cutting load amount is the difference of wind-powered electricity generation unit off-grid capacity and enable system reserve capacity.System takes the cutting load measure to being compensated by cutting load, will affect to a certain extent the economy of operation of power networks.At this moment, system's cutting load can be realized by means such as interruptible loads.Cutting load cost of compensation R due to the initiation of wind-powered electricity generation unit off-grid _offCan be expressed as:

$R_{\mathrm{off}}=\left\{\begin{array}{cc}\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_i\&times;(P_{\mathrm{off}}-P_R)\&times;k_L}{N}& P_R<P_{\mathrm{off}}\\ 0& P_R>P_{\mathrm{off}}\end{array}\right.---\left(13\right)$

$P_{\mathrm{off}}=\underset{j=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{P}_{\mathrm{jW}}\&CenterDot;g\left(U_j\right)---\left(14\right)$

In formula, P _jWFor and the wind-powered electricity generation capacity of site j access; k _LCost of compensation for the excision 1MW of system load; U _j0For under special scenes and the initial voltage value of site j; △ U _j1The voltage that causes wind farm grid-connected some j for the system failure under special scenes falls amplitude; △ U _j2For dynamic passive compensation under special scenes to and the voltage support amplitude of site j.

g(U _j) reflected the also running status of site j access wind energy turbine set, 1 expression off-grid, 0 represents not off-grid.g(U _j) will according to and the voltage U of site j _jContrast shown in Figure 1 taking parameter on trendline.And the voltage U of site j _jCan be by initial voltage U _j0, the voltage that causes of fault voltage support three parts falling amplitude and dynamic passive compensation and provide determine,

$U_j=U_{j0}-U_{\mathrm{jA}}+S_{\mathrm{ji}}\&times;\underset{i=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{Q}_{\mathrm{iSVC}}---\left(15\right)$

(5) concept of introducing risk helps the consequence that large-scale wind power unit off-grid produces when estimating that under different reactive power compensation configuring conditions, electrical network generation voltage falls.This evaluation procedure has comprised the key element of two aspects altogether, i.e. the consequence of reactive power compensation configuration and wind-powered electricity generation unit off-grid, and the consequence of wind-powered electricity generation unit off-grid comprises startup reserve capacity and issuable cutting load.Therefore, the risk of large-scale wind power unit off-grid should mainly be comprised of wind-powered electricity generation base reactive power compensation cost of investment, reserve capacity cost and cutting load cost of compensation three parts,

Risk=R _S+R _R+R _off (16)

Constraints is:

$\left\{\begin{array}{c}\mathrm{\&Delta;P}=P_{\mathrm{Gi}}-P_{\mathrm{Li}}+P_R-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}}+B_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}})=0\\ \mathrm{\&Delta;Q}=Q_{\mathrm{Gi}}-Q_{\mathrm{Li}}+Q_{\mathrm{iSVC}}-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}}-B_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}})=0\end{array}\right.---\left(17\right)$

$\left\{\begin{array}{ccccc}{Q}_{\mathrm{SVC}}^{\min }& \&le;& Q_{\mathrm{SVC}}& \&le;& Q_{\mathrm{SVC}}^{\max }\\ U_A^{\min }& \&le;& U_A& \&le;& U_A^{\max }\\ {P_R}^{\min }& \&le;& P_R& \&le;& {P_R}^{\max }\\ U_i^{\min }& \&le;& U_i& \&le;& U_i^{\max }\end{array}\right.---\left(18\right)$

Wherein, P _Gi, Q _GiBe respectively generating active power and the reactive power at node i place; P _Li, Q _LiBe respectively load active power and the reactive power of node i; Q _ISVCSVC compensation power for the reactive power compensation node i; U _iVoltage for node i; G _ij, δ _ijThe electricity that is respectively between node i, j is led and phase angle difference; N ₁Be nodes;

Be respectively the bound of the compensation capacity of reactive power compensation point SVC;

Be respectively scene lower node voltage and fall the amplitude bound;

Be respectively wind power system active reserve capacity bound;

Be respectively the node voltage bound.

Beneficial effect: the present invention proposes a kind of wind-powered electricity generation base reactive configuration method of considering operation risk, the method is based on the coordination of the resource such as adjustable standby, interruptible load in system, consider the various restrictions of wind energy turbine set idle work optimization, the operation risk minimum that dynamic process after falling take wind farm grid-connected point voltage produces is as optimization aim, adopt genetic algorithm, make the idle allocation plan in wind-powered electricity generation base optimum.Compare with the active power loss minimal configuration scheme that existing wind energy turbine set is commonly used, adopt this paper method can reduce the idle configuration capacity in wind-powered electricity generation base, minimizing system active reserve capacity, thereby reduced system operation cost, both help all kinds of regulation and control resources of abundant calling system, also be of value to assurance and site steady state voltage level and transient voltage characteristic.

Description of drawings

Fig. 1 is wind energy turbine set low voltage crossing specification requirement curve.

Fig. 2 is the general flow chart of the inventive method.

Fig. 3 is the power network wiring schematic diagram.

Fig. 4 is the flow chart of genetic algorithm.

Fig. 5 is that the inventive method, loss minimization optimized algorithm and the contrast of fixed proportion algorithm voltage curve are adopted in the also site of wind energy turbine set 1.

Fig. 6 is that the inventive method, loss minimization optimized algorithm and the contrast of fixed proportion algorithm voltage curve are adopted in the also site of wind energy turbine set 2.

Fig. 7 is that the inventive method, loss minimization optimized algorithm and the contrast of fixed proportion algorithm voltage curve are adopted in the also site of wind energy turbine set 3.

Embodiment:

With reference to the accompanying drawings and in conjunction with the embodiments the present invention is described in further detail.But the invention is not restricted to given example.

The present invention is mainly for the reactive power compensation allocation problem in wind-powered electricity generation base.For single wind energy turbine set, many typhoons group of motors can be equivalent becomes the wind energy turbine set of a plurality of different ruuning situations, thereby the research contents of single wind energy turbine set and wind-powered electricity generation base reactive power compensation configuration is similar, so the method that also can adopt the present invention to propose.

The present invention is used for the reactive power compensation configuration in wind-powered electricity generation base, domestic certain actual electric network wiring schematic diagram that comprises wind-powered electricity generation as shown in Figure 2, wherein LVRT is low voltage crossing LVRT (LowVoltageRideThrough).

Table 1 voltage falls probability distribution

The diversity that breaks down for simulation wind-powered electricity generation base, fall effect of optimization under scene to check method in this paper at different voltages, different voltages are occured electrical network falls amplitude and is divided into nine kinds of different scenes, and provide the probability that every kind of scene occurs, as shown in table 1ly ask for respectively that under different scenes, voltage falls issuable maximum operation risk in rear dynamic process, the operation risk desired value after obtaining at last voltage and falling.

1, according to the requirement of wind energy turbine set low voltage crossing technology judgement and site wind turbine group off-grid whether, if drop to less than 90% rated voltage and within the time that low voltage crossing allows at wind-powered electricity generation set grid-connection point voltage and do not take Measures of Reactive Compensation, can cause wind-powered electricity generation unit off-grid

For example, wind-powered electricity generation set grid-connection point voltage drops to 0.2, and allowing the most very much not off-grid running time according to the specification requirement LVRT Capability of Wind Turbine Generator is 625 milliseconds, and the operate time of Quick reactive-load compensation device is greater than 0.625 millisecond.

When if the most very much not off-grid running time that the Quick reactive-load compensation device action time allows less than or equal to low voltage crossing and reactive capability satisfy service requirement, wind-powered electricity generation unit off-grid not; When if the most very much not off-grid running time that allow greater than low voltage crossing the operate time of Quick reactive-load compensation device or reactive capability can not meet the demands, wind-powered electricity generation unit possibility off-grid adopts the optimization method of following step 2～step 5 to configure reactive compensation capacity and active reserve capacity.

2, can be in the hope of the sensitivity relation of wind energy turbine set access point i about self and wind energy turbine set reactive power based on the depression of order Jacobian matrix, and according to both the best access point of level of sensitivity judgement reactive power compensator;

Choosing wind energy turbine set access regional area is research object, if comprise m wind energy turbine set in the zone, and by n the main electrical network of access point access, can obtain only comprising 2 (m+n) exponent part node depression of order Jacobian matrix J of wind energy turbine set node and access point _SI, to J _SIInvert, can get

Can get i access point voltage according to formula (1) about the sensitivity relation that local reactive power changes is

S ₁=△U _i/△Q _i=a _{2m+n+i,2m+n+i} (2)

Simultaneously, can get wind energy turbine set outlet voltage about the sensitivity relation that the access point reactive power changes is

S ₂=△U _i/△Q _j=a _2m+n+i,m+n+j (3)

In embodiment, read the Voltage-Reactive Power sensitivity relation shown in table 2 and table 3, the optimal placement of judgement Reactive Compensation in Wind Farm device; For example and site 1(PCC1) voltage be 0.01098 about the sensitivity that the reactive power of PCC1 changes, and wind energy turbine set outlet voltage is 0.01096 about the sensitivity that the reactive power of PCC1 changes, and the optimal placement of the reactive power compensator of wind energy turbine set 1 is the access point place; For example the voltage of PCC2 is 0.00601 to the reactive power changing sensitivity of PCC1, the reactive power compensator that wind energy turbine set 1 is described to and site 2 the voltage support effect is arranged equally, just the action effect of compensation arrangement with respect to self is less.

Table 2 access point voltage is about each access point reactive power changing sensitivity

Table 3 wind energy turbine set outlet voltage is about each access point reactive power changing sensitivity

Can get by table 1 probability that under nine kinds of different scenes, voltage falls, ask for respectively the voltage deviation of each access point under every kind of scene, can ask for the dynamic reactive configuration capacity of wind energy turbine set diverse access point configuration under special scenes according to the voltage deviation of the Voltage-Reactive Power sensitivity relation of having asked and each access point:

$Q_{\mathrm{SVC}}=\underset{j=1}{\overset{3}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{U}_j/S_j---\left(4\right)$

The cost of compensation that known 1MVar is idle is k _SVC=300 yuan/MVar, and then the cost of investment desired value that can calculate reactive-load compensation equipment is:

$R_S=\frac{\underset{i=1}{\overset{9}{\mathrm{\&Sigma;}}}{p}_i\&times;Q_{\mathrm{SVC}}\&times;k_{\mathrm{SVC}}}{9}---\left(5\right)$

If the reactive-load compensation equipments of 3 configurations can do nothing to help wind farm grid-connected point voltage and return to rational scope and can cause wind-powered electricity generation unit off-grid, the active power vacancy that needs the system reserve balance to cause thus.The probability that under known nine kinds of different scenes, voltage falls is if the active reserve capacity of regional power grid is P _R, the cost of configuration 1MW active reserve capacity is k _R=140 yuan/MW, the operating cost desired value that can calculate active reserve capacity is

$R_R=\frac{\underset{i=1}{\overset{9}{\mathrm{\&Sigma;}}}{p}_i\&times;P_R\&times;k_R}{9}---\left(6\right)$

4 and the voltage U of site j _jCan be by initial voltage U _j0, the voltage that causes of fault voltage support three parts falling amplitude and dynamic passive compensation and provide determine,

$U_j=U_{j0}-U_{\mathrm{jA}}+S_{\mathrm{ji}}\&times;\underset{i=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{Q}_{\mathrm{iSVC}}---\left(7\right)$

In formula, first, right side U _j0For and the initial voltage value of site j; Second, the right side voltage that causes for fault falls amplitude, U _jAThe voltage that propagates into node j for false voltage under scenario A falls amplitude; The voltage support that the 3rd, right side provides for dynamic passive compensation, S _jiFor and the voltage of site j to the sensitivity of node i reactive power compensation, Q _ISVCFor and the reactive compensation capacity of site i.

The off-grid capacity of wind-powered electricity generation unit is

$P_{\mathrm{off}}=\underset{j=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{P}_{\mathrm{jW}}\&CenterDot;g\left(U_j\right)---\left(8\right)$

g(U _j) reflected the also running status of site j access wind energy turbine set, 1 expression off-grid, 0 represents not off-grid.g(U _j) will according to and the voltage U of site j _jContrast shown in Figure 1 taking parameter on trendline.

Cutting load cost of compensation desired value R due to the initiation of wind-powered electricity generation unit off-grid _offCan be expressed as:

$R_{\mathrm{off}}=\left\{\begin{array}{c}\frac{\underset{i=1}{\overset{9}{\mathrm{\&Sigma;}}}{p}_i\&times;(P_{\mathrm{off}}-P_R)\&times;k_L}{9},P_R<P_{\mathrm{off}}\\ 0,P_R>P_{\mathrm{off}}\end{array}\right.---\left(9\right)$

5, the risk of large-scale wind power unit off-grid should mainly be comprised of wind-powered electricity generation base reactive power compensation cost of investment, reserve capacity cost and cutting load cost of compensation three parts, calculates active reserve capacity P according to formula (10) and constraints _RWith reactive compensation capacity Q _SVC:

Risk=R _S+R _R+R _off (10)

Constraints is:

$\left\{\begin{array}{c}\mathrm{\&Delta;P}=P_{\mathrm{Gi}}-P_{\mathrm{Li}}+P_R-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}}+B_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}})=0\\ \mathrm{\&Delta;Q}=Q_{\mathrm{Gi}}-Q_{\mathrm{Li}}+Q_{\mathrm{iSVC}}-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}}-B_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}})=0\end{array}\right.---\left(11\right)$

$\left\{\begin{array}{ccccc}{Q}_{\mathrm{SVC}}^{\min }& \&le;& Q_{\mathrm{SVC}}& \&le;& Q_{\mathrm{SVC}}^{\max }\\ U_A^{\min }& \&le;& U_A& \&le;& U_A^{\max }\\ P_R^{\min }& \&le;& P_R& \&le;& P_R^{\max }\\ U_i^{\min }& \&le;& U_i& \&le;& U_i^{\max }\end{array}\right.---\left(12\right)$

Wherein, P _Gi, Q _GiBe respectively generating active power and the reactive power at node i place; P _Li, Q _LiBe respectively load active power and the reactive power of node i; Q _ISVCSVC compensation power for the reactive power compensation node i; U _iVoltage for node i; G _ij, δ _ijThe electricity that is respectively between node i, j is led and phase angle difference; N ₁Be nodes;

Be respectively the bound of the compensation capacity of reactive power compensation point SVC; Be respectively scene lower node voltage and fall the amplitude bound;

Be respectively wind power system active reserve capacity bound;

Be respectively the node voltage bound.

By above method, obtain the voltage curve of three wind farm grid-connected points, as Fig. 5～7.

By Fig. 5～Fig. 7 as seen, the idle allocation plan that adopts the fixed proportion collocation method to obtain, also site transient voltage characteristic is the poorest under the condition that same fault occurs, and the scheme that the idle allocation plan that employing this paper method obtains and loss minimization optimization method obtain, and the transient voltage characteristic of site is basic identical.

Can find out by above contrast: the coordination based on the resource such as adjustable standby, interruptible load in system of the present invention, consider the various restrictions of wind energy turbine set idle work optimization, abundant all kinds of regulation and control resources of calling system, in assurance and site steady state voltage level and transient voltage characteristic, can reduce the idle configuration capacity in wind-powered electricity generation base, minimizing system active reserve capacity, thus system operation cost reduced.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the prerequisite that does not break away from the principle of the invention, can also make the some improvements and modifications that can expect, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (6)

1. a wind-powered electricity generation base reactive configuration method, comprise the steps:

(1) probability that falls according to system voltage under different scenes is asked for based on electric network theory the voltage that false voltage under described different scene propagates into wind farm grid-connected point and is fallen amplitude;

(2) based on the curve that requires of wind energy turbine set low voltage crossing technology, judge that system voltage falls whether can cause grid connected wind power unit off-grid;

(3) set up the risk indicator model that system voltage falls;

Cutting load cost of compensation, the cost of investment of reactive-load compensation equipment and the operating cost of system's active reserve capacity that when (4) falling according to electrical network generation voltage, large-scale wind power unit off-grid causes are set up and are taken into account the wind-powered electricity generation base idle work optimization allocation models that system voltage falls risk;

(5) adopt genetic algorithm to carry out idle work optimization to taking into account of setting up of step (4) the wind-powered electricity generation base idle work optimization allocation models that system voltage falls risk and calculate, obtain best reactive compensation capacity, active reserve capacity and system's cutting load capacity.

2. a kind of wind-powered electricity generation base reactive configuration method according to claim 1 is characterized in that step (1) is described to ask for based on electric network theory voltage that false voltage under described different scene propagates into wind farm grid-connected point and fall amplitude and be:

If the system impedance matrix is Z, the promise equivalence that pauses is done by system, obtain the Equivalent admittance battle array Y of system _eqAnd Injection Current

${\stackrel{\&CenterDot;}{I}}_{\mathrm{eq}}^{\left(0\right)}=Y_{\mathrm{eq}}\&CenterDot;{\stackrel{\&CenterDot;}{U}}_{\mathrm{eq}}^{\left(0\right)}---\left(1\right)$

${\stackrel{\&CenterDot;}{U}}_{\mathrm{eq}}^{\left(0\right)}=M_F^T\&CenterDot;{\stackrel{\&CenterDot;}{U}}^{\left(0\right)}---\left(2\right)$

Calculating the non-working port voltage and current is,

${\stackrel{\&CenterDot;}{U}}_F={(I+Z_{\mathrm{eq}}\&CenterDot;Y_F)}^{-1}\&CenterDot;{\stackrel{\&CenterDot;}{U}}_{\mathrm{eq}}^{\left(0\right)}---\left(3\right)$

${\stackrel{\&CenterDot;}{I}}_F=Y_F\&CenterDot;{\stackrel{\&CenterDot;}{U}}_F---\left(4\right)$

False voltage propagates into and the voltage of site j falls amplitude and is,

$U_{\mathrm{jA}}=Z\&CenterDot;M_F\&CenterDot;{\stackrel{\&CenterDot;}{I}}_F---\left(5\right)$

In formula, Be node-port association matrix, Y _FBe the admittance of malfunctioning node ground connection, I is unit matrix.

3. whether a kind of wind-powered electricity generation base reactive configuration method according to claim 2, is characterized in that the described curve that requires based on wind energy turbine set low voltage crossing technology of step (2), judge that system voltage falls can cause grid connected wind power unit off-grid to be:

When if the most very much not off-grid running time that the Quick reactive-load compensation device action time allows less than or equal to low voltage crossing and reactive capability satisfy service requirement, wind-powered electricity generation unit off-grid not; When if the most very much not off-grid running time that allow greater than low voltage crossing the operate time of Quick reactive-load compensation device or reactive capability can not meet the demands, wind-powered electricity generation unit possibility off-grid adopts the optimization method of following step 2～step 5 to configure reactive compensation capacity and active reserve capacity.

4. a kind of wind-powered electricity generation base reactive configuration method according to claim 2, wherein said wind-powered electricity generation set grid-connection point voltage can guarantee not off-grid operation 625ms when dropping to 20% rated voltage, wind farm grid-connected point voltage is when 2s can return to 90% rated voltage after falling, and the wind-powered electricity generation unit can guarantee off-grid operation; If drop to less than 90% rated voltage and within the time that low voltage crossing allows at wind-powered electricity generation set grid-connection point voltage and do not take Measures of Reactive Compensation, can cause wind-powered electricity generation unit off-grid.

5. a kind of wind-powered electricity generation base reactive configuration method according to claim 3, it is characterized in that risk indicator that the described system voltage of step (3) falls is that the consequence that in the possibility that occured by system's different faults and wind energy turbine set, wind-powered electricity generation unit off-grid causes defines, its mathematical description is:

Risk(A)=P _r,A×S _ev,A （6）

In formula, P _r,ARepresent the probability that under different scenes, system voltage falls; S _{Ev, A}Fall the consequence that causes for system voltage.

6. a kind of wind-powered electricity generation base reactive configuration method according to claim 5 is characterized in that the described foundation of step (4) takes into account the wind-powered electricity generation base idle work optimization allocation models that system voltage falls risk, and concrete steps are as follows:

Cutting load cost of compensation, the cost of investment of reactive-load compensation equipment and the operating cost of system's active reserve capacity that when falling according to electrical network generation voltage, large-scale wind power unit off-grid causes, set up corresponding Optimized model:

minRisk=R _S+R _R+R _off （7）

In formula, R _S, R _R, R _offBe respectively the cost of investment of reactive-load compensation equipment, the cost of system's active reserve capacity and the cost of compensation that wind-powered electricity generation unit off-grid causes cutting load to cause,

Wherein, the cost of investment R of dynamic passive compensation capacity _SRelevant to the horizontal desired value of the voltage control of each wind energy turbine set access point, the cost of investment R of described dynamic passive compensation _SCan be expressed as

$R_S=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_i\&times;Q_{\mathrm{SVC}}\&times;k_{\mathrm{SVC}}}{N}---\left(8\right)$

$Q_{\mathrm{SVC}}=\underset{j=1}{\overset{N_W}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}{U}_j/S_j---\left(9\right)$

In formula, p _iProbability, Q for a certain special scenes generation _svcDynamic passive compensation capacity, scene number, the k of N for occurring for wind energy turbine set access point configuration under special scenes _svcBe the idle needed cost of compensation 1Mvar, S _jFor the voltage of access point j about the idle sensitivity in this locality, △ U _jVoltage deviation, N for access point j _WSum for wind energy turbine set in regional power grid;

Wherein, be the generation of reply wind-powered electricity generation unit off-grid accident, system will increase a certain proportion of standby on original standby basis;

When system's generation voltage falls when causing wind-powered electricity generation unit off-grid, enable spinning reserve and can effectively alleviate impact on system, generally, the spinning reserve capacity that configures in system accounts for 5%～10% of system's total load, and operating cost is relatively high, the operating cost R of system's reserve _RCan be expressed as:

$R_R=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_i\&times;P_R\&times;k_R}{N}---\left(10\right)$

In formula, P _RActive reserve capacity, k for regional power grid _RCost for configuration 1MW spinning reserve capacity;

If dynamic passive compensation configuration and system's reserve arrange unreasonable, in order to guarantee the balance of system's active power, wind-powered electricity generation unit off-grid might cause the cutting load measure, the cutting load amount is the difference of wind-powered electricity generation unit off-grid capacity and enable system reserve capacity, the cutting load cost of compensation R that wind-powered electricity generation unit off-grid causes _offCan be expressed as:

$R_{\mathrm{off}}=\left\{\begin{array}{cc}\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_i\&times;(P_{\mathrm{off}}-P_R)\&times;k_L}{N}& P_R<P_{\mathrm{off}}\\ 0& P_R>P_{\mathrm{off}}\end{array}\right.---\left(11\right)$

$P_{\mathrm{off}}=\underset{j=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{P}_{\mathrm{jW}}\&CenterDot;g\left(U_j\right)---\left(12\right)$

In formula, P _jWWind-powered electricity generation capacity, k for also site j access _LCost of compensation, U for the excision 1MW of system load _j0For under special scenes and initial voltage value, the △ U of site j _j1For causing the voltage of wind farm grid-connected some j, the system failure under special scenes falls amplitude, △ U _j2For dynamic passive compensation under special scenes to and the voltage support amplitude of site j;

g(U _j) running status of reflection and site j access wind energy turbine set, it is to represent off-grid at 1 o'clock, 0 represents not off-grid, and the voltage U of site j _jCan be by initial voltage U _j0, the voltage that causes of fault voltage support three parts falling amplitude and dynamic passive compensation and provide determine,

$U_j=U_{j0}-U_{j_A}+S_{\mathrm{ji}}\&times;\underset{i=1}{\overset{N_W}{\mathrm{\&Sigma;}}}{Q}_{\mathrm{iSVC}}---\left(13\right)$

Variable bound is divided into trend equality constraint and operation variable bound:

The trend equality constraint is:

$\left\{\begin{array}{c}\mathrm{\&Delta;P}=P_{\mathrm{Gi}}-P_{\mathrm{Li}}+P_R-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}}+B_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}})=0\\ \mathrm{\&Delta;Q}=Q_{\mathrm{Gi}}-Q_{\mathrm{Li}}+Q_{\mathrm{iSVC}}-\\ U_i\underset{i=1}{\overset{N_1}{\mathrm{\&Sigma;}}}{U}_j(G_{\mathrm{ij}}\sin {\mathrm{\&delta;}}_{\mathrm{ij}}-B_{\mathrm{ij}}\cos {\mathrm{\&delta;}}_{\mathrm{ij}})=0\end{array}\right.---\left(14\right)$

The operation variable bound is:

$\left\{\begin{array}{ccccc}{Q}_{\mathrm{SVC}}^{\min }& \&le;& Q_{\mathrm{SVC}}& \&le;& Q_{\mathrm{SVC}}^{\max }\\ U_A^{\min }& \&le;& U_A& \&le;& U_A^{\max }\\ {P_R}^{\min }& \&le;& P_R& \&le;& {P_R}^{\max }\\ U_i^{\min }& \&le;& U_i& \&le;& U_i^{\max }\end{array}\right.---\left(15\right)$

In formula, P _Gi, Q _GiBe respectively generating active power and the reactive power at node i place, P _Li, Q _LiBe respectively load active power and the reactive power of node i, Q _ISVCBe the SVC compensation power of reactive power compensation node i, U _iBe the voltage of node i, G _ij, δ _ijThe electricity that is respectively between node i, j is led and phase angle difference, N ₁Be nodes,

Be respectively the bound of the compensation capacity of reactive power compensation point SVC, Be respectively scene lower node voltage and fall the amplitude bound, Be respectively wind power system active reserve capacity bound,

Be respectively the node voltage bound.

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