CN102684201B - Voltage threshold probability-based reactive power optimizing method for grid containing wind power plant - Google Patents

Abstract

The invention provides a reactive power optimization method for a power grid containing a wind farm based on the probability of voltage exceeding the limit, so as to solve the problem that the voltage optimization control of the automatic voltage control system is not effective when the wind power is connected to the grid. The specific steps are as follows: first, collect the operating parameters of the power grid, the basic parameters of the wind turbines in each wind farm, and the active output data of the wind farm; secondly, obtain the voltage influence factor, the power conversion coefficient of the wind turbine, and the active power probability distribution equation of the wind farm through the above parameters, Then it can be used to obtain the probability of voltage exceeding the limit; finally, based on the probability of voltage exceeding the limit, a reactive power optimization model is established, and the genetic algorithm is used to solve the model to obtain the control instructions of the reactive power equipment. The present invention proposes a reactive power optimization method for power grids containing wind farms based on the probability of voltage exceeding the limit. This method is used to replace the reactive power optimization method of the current automatic voltage control system, so that the voltage optimization control of the automatic voltage control system can be effective under wind power grid connection. Control the reactive equipment in the power grid accurately to ensure the safe and economical operation of the power grid.

Description

A kind of based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method

Technical field

The present invention relates to the idle operation method of electric power system, particularly a kind of electric network reactive-load operation method that comprises wind energy turbine set.

Background technology

Along with the increase of wind energy turbine set access quantity and capacity, the randomness of wind power and intermittence will be brought fluctuation more fast to system voltage, the automatic voltage control system calculating based on timing idle work optimization will be greatly affected and frequent operation, often not reach the effect of damaging and ensureing quality of voltage of falling of its expection.

Specifically, the control strategy of area power grid automatic voltage control system is made up of the region idle work optimization control strategy of the Correction Strategies on the spot starting at any time and regularly (such as every 15-30 minute) startup conventionally.The latter normally calculates and controls for the current time section of electrical network, and the voltage control of guiding whole day realizes the excellent control of becoming of saving energy and decreasing loss, and the local voltage that occurs is during this time out-of-limit is gone to adjust by Correction Strategies part on the spot.If voltage fluctuation degree is less in this cycle, automatic voltage control system can be taken into account whole day saving energy and decreasing loss, ensures that voltage is qualified and avoid economy and the fail safe needs of equipment frequent operation.But the fluctuation of wind power is more complicated than load fluctuation property, more acutely, more frequent.Because idle work optimization is pursued the result of falling damage and is often caused part of nodes voltage to level off to upper voltage limit operation, be subject to the exert oneself impact of quick frequent fluctuation of wind-powered electricity generation, the voltage of these nodes will fluctuate continually and is out-of-limit every now and then, causes the frequent operation of regulating and controlling voltage equipment and affects its service life, increases system operation risk.

The present invention is converted into voltage out-of-limit probability the probability distribution equation of wind energy turbine set power and is incorporated in the reactive power optimization containing wind energy turbine set, thereby improve the validity of automatic voltage control system idle work optimization, idle work optimization can be brought into play in the electrical network that comprises wind energy turbine set and fall the effect of damaging and ensureing quality of voltage, make electrical network can receive more clean wind power generation.

Summary of the invention

Can not play falling of expection and damage and ensure the problem of quality of voltage in order to solve wind farm grid-connected lower traditional idle work optimization, make electrical network can receive more wind power generation, the present invention proposes based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method.

Based on voltage out-of-limit probability containing a wind energy turbine set reactive power optimization method, comprise the following steps:

(1) gather the blower foundation parameter of operation of power networks parameter, each wind energy turbine set and the long-time section of wind energy turbine set meritorious go out force data; Operation of power networks parameter comprises: power network topology, line parameter circuit value, transformer station's parameter, load parameter, generator parameter, node voltage allow range of operation, reactive-load compensation equipment parameter, node serial number set N and wind energy turbine set numbering set W; Power network topology refers to the connected mode of circuit and circuit, circuit and transformer in electrical network, and the line parameter circuit value of each circuit comprises circuit unit resistance r _o, the reactance x of circuit unit _lo, the susceptance X of circuit unit _cowith line length L; Transformer station's parameter comprises transformer number n _t, the equivalent resistance r of each transformer _t, equivalent reactance x _t, transformer equivalent no-load voltage ratio k _t, no-load voltage ratio upper limit k _maxwith no-load voltage ratio lower limit k _min; The load parameter of each node includes workload P _lNwith load or burden without work Q _lN; Generator parameter comprises as the active power of traditional power plant of PV node (meritorious exert oneself and the controlled node of grid-connected busbar voltage) and voltage, as the active power of traditional power plant of PQ node (meritorious exerting oneself and the idle controlled node of exerting oneself) and reactive power and as voltage and the phase angle of traditional power plant of V θ node (node that voltage and phase angle are controlled); Node voltage allowed band comprises that node voltage allows upper limit V _maxallow lower limit V with node voltage _min; Reactive-load compensation equipment parameter comprises that the capacitor group of each node counts n _cwith every pool-size n _co, each node Reactor banks count n _lwith every pool-size n _lo; The underlying parameter of each wind electric field blower comprises the rated power P of blower fan _n, incision wind speed v _in, cut-out wind speed v _out, rated wind speed v _nwith wind sweeping area A;

(2) by operation of power networks calculation of parameter electric network swim, obtain the voltage influence factor, i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i; Calculate the power conversion coefficient C of blower fan by the underlying parameter of blower fan _p.By wind energy turbine set meritorious go out force data and least square fitting ask for dimensional parameters c and the form parameter k of the meritorious probability distribution equation of wind energy turbine set; Voltage influence factor K _ijand K _i, the power conversion coefficient C of blower fan _pcan be used for computing node voltage out-of-limit probability with meritorious probability distribution equation;

(3) taking the weighted sum of network loss and the out-of-limit maximum probability value of node voltage as target function, with power flow equation, node voltage range of operation, the scope of exerting oneself that reactive power source is idle, reactive-load compensation equipment idle exert oneself and the range constraint of transferring the files of transformer be constraints build based on voltage out-of-limit probability containing wind energy turbine set idle work optimization model;

(4) adopt genetic algorithm for solving based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization model, automatic voltage control system, according to the control command of sending reactive apparatus based on the solving result containing wind energy turbine set reactive power optimization model of voltage out-of-limit probability, is controlled the action of reactive apparatus.

Above-mentioned containing in wind energy turbine set reactive power optimization method based on voltage out-of-limit probability, it is according to given power network topology, line parameter circuit value, transformer station's parameter and generator parameter, load parameter that described trend is calculated, and determines the calculating of meritorious, idle, voltage and the phase angle of the each node of electrical network by mathematical computations.It is the most basic calculating of power system analysis that trend is calculated.

Above-mentioned based on voltage out-of-limit probability containing in wind energy turbine set reactive power optimization method, the described voltage influence factor refers to the influence degree of wind energy turbine set to a certain grid nodes voltage.The voltage influence factor is divided two kinds: i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i.Both passes are

$K_i=n_W/\left(\underset{j\∈W}{\mathrm{\Σ}}\frac{1}{K_{\mathrm{ij}}}\right)---\left(1\right)$

Local voltage factor of influence K _ijunder wind energy turbine set j independent role, cause the active power variable quantity of the required wind energy turbine set j of per unit node i voltage variety.Each wind energy turbine set is carried out to twice trend calculating, and the operation of power networks parameter that twice trend calculated remains unchanged, and calculates for the first time zero of wind energy turbine set, calculates for the second time that wind energy turbine set is completely sent out and with given hysteresis firm power factor φ operation, local voltage factor of influence K _ijcomputational methods be

$K_{\mathrm{ij}}=\frac{P_{\mathrm{jN}}}{\mathrm{\Δ}{V}_{\mathrm{ijMax}}}---\left(2\right)$

In formula, P _jNfor the installed capacity of wind energy turbine set j; Δ V _ijMaxfor the voltage variety of twice trend calculating of node i.

Overall situation voltage influence factor K _irefer to simultaneously under all wind energy turbine set affect, cause total active power variable quantity of the required all wind energy turbine set of per unit node i voltage variety.

Above-mentioned based on voltage out-of-limit probability containing in wind energy turbine set reactive power optimization method, it is characterized in that: described power conversion coefficient C _prefer to the ratio of blower fan electromagnetic power and wind wheel mechanical output.Can be obtained by following formula estimation.

$C_p=\frac{{2P}_N}{\mathrm{\ρA}{v}_N^3}---\left(3\right)$

Above-mentioned based on voltage out-of-limit probability containing in wind energy turbine set reactive power optimization method, the meritorious probability distribution equation of described wind energy turbine set refers to the meritorious probability expression of exerting oneself of wind energy turbine set, its expression formula is

$\mathrm{\&beta;}\left(P\right)=\left\{\begin{array}{cc}1-\exp [-{\left(\frac{v_{\mathrm{in}}}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)}^k]& (0\&le;P<P_1)\\ 1-\exp [-{\left(\frac{v_p}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)}^k]& ({\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="120530094529.png,120530094554.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&le;P<P_N)\\ 1& (P=P_N)\end{array}\right.---\left(4\right)$

In formula, meritorious the exerting oneself that P is blower fan; P ₁for wind speed is v _inthe meritorious of Shi Fengji exerted oneself; v _pfor being less than rated power and being greater than P as the meritorious P that exerts oneself of blower fan ₁meritorious wind speed corresponding to P of exerting oneself of Shi Fengji.V _pcomputational methods be

$v_p=\sqrt[3]{\frac{2P}{C_P\mathrm{A\&rho;}}}---\left(5\right)$

In formula, C _pfor wind energy conversion efficiency, ρ is the atmospheric density of wind wheel hub At The Height, and A is wind wheel wind sweeping area.

Above-mentioned containing in wind energy turbine set reactive power optimization method based on voltage out-of-limit probability, described voltage out-of-limit probability refers under steady state condition, in a control cycle of automatic voltage control system, there is out-of-limit probability in the node voltage of electrical network wind-engaging electric field influence.Voltage out-of-limit probability divides two kinds: the out-of-limit probability β of local voltage _ijwith overall voltage out-of-limit probability β _i.

The out-of-limit probability β of local voltage _ijrefer to the probability that voltage out-of-limit occurs when node i is affected separately by wind energy turbine set j.If node i voltage allows intermediate value V _i ⁰for the intermediate value of node voltage permission range of operation.?

${V_i}^0=\frac{1}{2}(V_{\mathrm{iMin}}+V_{i\max })---\left(6\right)$

In formula, V _imaxnode i voltage allows the upper limit and V _iminnode i voltage allows lower limit.

When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be greater than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

In formula, n _jfor wind energy turbine set j blower fan number,

referring to will

substitution (4) in P calculate,

referring to will p in substitution (4) calculates;

When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be less than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

In formula,

referring to will

substitution (4) in P calculate,

referring to will

p in substitution (4) calculates;

Therefore, the overall voltage out-of-limit probability β of node i _ifor

${\mathrm{\&beta;}}_i=\frac{K_i}{n_W}\underset{j\&Element;W}{\mathrm{\&Sigma;}}\frac{{\mathrm{\&beta;}}_{\mathrm{ij}}}{K_{\mathrm{ij}}}---\left(9\right)$

Above-mentioned based on voltage out-of-limit probability containing in wind energy turbine set reactive power optimization method, describedly comprise target function and constraints two parts based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization model.

The target function containing wind energy turbine set reactive power optimization model based on voltage out-of-limit probability is

$\min f={\mathrm{\&omega;}}_1{P}_L+{\mathrm{\&omega;}}_2\underset{i\&Element;N}{\mathrm{Max}}{\mathrm{\&beta;}}_i---\left(10\right)$

In formula, P _lfor network loss,

represent to solve the maximum of all node overall situation voltage out-of-limit probability.ω ₁, ω ₂for weight coefficient, span is 0 ~ 1, generally gets ω ₁be 0.2, ω ₂be 0.8.Network loss P _lcomputational methods be

$P_L=\underset{i\&Element;N,j\&Element;N}{\mathrm{\&Sigma;}}{\left|\frac{V_i-V_j}{r_{\mathrm{oij}}+x_{\mathrm{Loij}}}\right|}^2\frac{r_{\mathrm{oij}}}{L_{\mathrm{ij}}}---\left(11\right)$

In formula, V _iand V _jbe respectively the voltage of i node and j node.R _oijfor circuit unit resistance, x between node i and node j _loijfor the circuit unit's reactance between node i and node j, L _ijfor the line length between node i and node j.

The constraints containing wind energy turbine set reactive power optimization model based on voltage out-of-limit probability is power flow equation constraint, the constraint of node voltage allowed band, generator reactive exert oneself range constraint, the idle units limits of reactive-load compensation equipment and the range constraint of transferring the files of transformer.

Above-mentioned based on voltage out-of-limit probability containing in wind energy turbine set reactive power optimization method, described genetic algorithm is a kind of intelligent search algorithm of conventional solving-optimizing model optimal solution.

Containing compared with wind energy turbine set idle work optimization method, the present invention has following advantage with existing:

(1) the present invention has taken into full account randomness and the intermittent impact on line voltage control of wind power, has proposed first voltage out-of-limit probability and the computational methods thereof of the lower grid nodes of wind energy turbine set impact.

(2) the present invention is incorporated into grid nodes voltage out-of-limit probability in the modeling of reactive power optimization method, idle work optimization method is improved greatly to the adaptability of wind power, make idle work optimization method under wind farm grid-connected, still can play the effect of damaging and ensureing quality of voltage of falling.

(3) institute of the present invention extracting method is applied in the existing region idle work optimization control module of automatic voltage control system, to replace its original idle work optimization method, without the hardware configuration of automatic voltage control system itself is modified.Method practical, easily promotes.

Brief description of the drawings

Fig. 1 is the schematic flow sheet containing wind energy turbine set reactive power optimization method based on voltage out-of-limit probability.

Fig. 2 is certain urban distribution network schematic diagram.

Fig. 3 is the long-time meritorious schematic diagram of exerting oneself of wind energy turbine set Y.

Fig. 4 is that wind energy turbine set Y has actual work exert oneself probability distribution and matching schematic diagram.

Fig. 5 a, Fig. 5 b adopt the wind energy turbine set reactive power optimization method that contains based on voltage out-of-limit probability to be optimized the 110kV line voltage distribution map of controlling after front and optimal control.

Fig. 6 a, Fig. 6 b adopt the wind energy turbine set reactive power optimization method that contains based on voltage out-of-limit probability to be optimized the voltage out-of-limit probability graph of controlling after front and optimal control.

Embodiment

Below in conjunction with accompanying drawing and example, specific embodiment of the invention is described further, but the enforcement of this explanation and protection are not limited to this.

The wind energy turbine set reactive power optimization method that contains based on voltage out-of-limit probability comprises:

(1) gather operation of power networks parameter, the long-time section of the blower foundation parameter of each wind energy turbine set and wind energy turbine set meritorious go out force data.Operation of power networks parameter comprises: power network topology, line parameter circuit value, transformer station's parameter, load parameter, generator parameter, node voltage allow range of operation, reactive-load compensation equipment parameter, node serial number collection N and wind energy turbine set numbering W.Power network topology refers to the connected mode of circuit and circuit, circuit and transformer in electrical network.The line parameter circuit value of each circuit comprises circuit unit resistance r _o, the reactance x of circuit unit _lo, the susceptance X of circuit unit _cowith line length L.Transformer station's parameter of each transformer station comprises transformer number n _t, the equivalent resistance r of each transformer _t, equivalent reactance x _t, transformer equivalent no-load voltage ratio k _t, no-load voltage ratio upper limit k _maxwith no-load voltage ratio lower limit k _min.The load parameter of each node includes workload P _lNwith load or burden without work Q _lN.Generator parameter comprises as the active power of traditional power plant of PV node and voltage, as the active power of traditional power plant of PQ node and reactive power and as voltage and the phase angle of traditional power plant of V θ node.Node voltage allowed band comprises that node voltage allows upper limit V _maxallow lower limit V with node voltage _min.Reactive-load compensation equipment parameter comprises that the capacitor group of each node counts n _cwith every pool-size n _co, each node Reactor banks count n _lwith every pool-size n _lo.The underlying parameter of each wind electric field blower comprises the rated power P of blower fan _n, incision wind speed v _in, cut-out wind speed v _out, rated wind speed v _n, wind sweeping area A.

(2) by operation of power networks calculation of parameter electric network swim, obtain the voltage influence factor, i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i.Calculate the power conversion coefficient C of blower fan by the underlying parameter of blower fan _p.By wind energy turbine set meritorious go out force data and least square fitting ask for dimensional parameters c and the form parameter k of the meritorious probability distribution equation of wind energy turbine set; Voltage influence factor K _ijand K _i, the power conversion coefficient C of blower fan _pcan be used for computing node voltage out-of-limit probability with meritorious probability distribution equation.

It is the most basic calculating of power system analysis that trend is calculated.Trend is calculated according to given power network topology, line parameter circuit value, transformer station's parameter and generator parameter, load parameter, determines meritorious, idle, voltage and the phase angle of the each node of electrical network by mathematical computations.

The voltage influence factor refers to the influence degree of wind energy turbine set to a certain grid nodes voltage.The voltage influence factor is divided two kinds: i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i.

Local voltage factor of influence K _ijunder wind energy turbine set j independent role, cause the active power variable quantity of the required wind energy turbine set j of per unit node i voltage variety.Each wind energy turbine set is carried out to twice trend calculating, the operation of power networks parameter of twice trend calculating remains unchanged, and wind energy turbine set is moved with given hysteresis firm power factor φ, calculates for the first time zero of wind energy turbine set (meritorious exerting oneself is 0), calculate for the second time wind energy turbine set and completely send out, local voltage factor of influence K _ijcomputational methods be

$K_{\mathrm{ij}}=\frac{P_{\mathrm{jN}}}{\mathrm{\&Delta;}{V}_{\mathrm{ijMax}}}$

In formula, P _jNfor the installed capacity of wind energy turbine set j; Δ V _ijMaxfor the voltage variety of twice trend calculating of node i.

Overall situation voltage influence factor K _irefer to simultaneously under all wind energy turbine set affect, cause total active power variable quantity of the required all wind energy turbine set of per unit node i voltage variety.It and local voltage factor of influence K _ijpass be

$K_i=n_W/\left(\underset{j\&Element;W}{\mathrm{\&Sigma;}}\frac{1}{K_{\mathrm{ij}}}\right)$

Power conversion coefficient C _prefer to the ratio of blower fan electromagnetic power and wind wheel mechanical output.Can be obtained by following formula estimation.

$C_p=\frac{2P_N}{\mathrm{\&rho;A}{\mathrm{<figure-callout\; id="3"\; label="v\; N"\; filenames="120530094529.png"\; state="\{\{state\}\}">v</figure-callout>}}_N^{}}$

The meritorious probability distribution equation of further introducing wind energy turbine set, ρ is the atmospheric density of wind wheel hub At The Height, A is wind wheel wind sweeping area, P _nfor the rated power of blower fan, v _nfor the rated wind speed of blower fan.

The meritorious probability distribution equation of wind energy turbine set refers to the meritorious probability expression of exerting oneself of wind energy turbine set, and its expression formula is

$\mathrm{\&beta;}\left(P\right)=\left\{\begin{array}{cc}1-\exp [-{\left(\frac{v_{\mathrm{in}}}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)}^k]& (0\&le;P<P_1)\\ 1-\exp [-{\left(\frac{v_p}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)]}^k& ({\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="120530094529.png,120530094554.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&le;P<P_N)\\ 1& (P=P_N)\end{array}\right.$

In formula, meritorious the exerting oneself that P is blower fan; P ₁for wind speed is v _inthe meritorious of Shi Fengji exerted oneself; v _pfor being less than rated power and being greater than P as the meritorious P that exerts oneself of blower fan ₁meritorious wind speed corresponding to P of exerting oneself of Shi Fengji.V _pcomputational methods be

$v_p=\sqrt[3]{\frac{2P}{C_P\mathrm{A\&rho;}}}$

In formula, C _pfor wind energy conversion efficiency, ρ is the atmospheric density of wind wheel hub At The Height, and A is wind wheel wind sweeping area.

The power conversion coefficient C of blower fan _pcan be used for computing node voltage out-of-limit probability with the meritorious probability distribution equation of wind energy turbine set.Below introduce implication and the computational methods of voltage out-of-limit probability.

Voltage out-of-limit probability refers under steady state condition, and in a control cycle of automatic voltage control system, out-of-limit probability occurs the node voltage of electrical network wind-engaging electric field influence.Voltage out-of-limit probability divides two kinds: the out-of-limit probability β of local voltage _ijwith overall voltage out-of-limit probability β _i.

The out-of-limit probability β of local voltage _ijrefer to the probability that voltage out-of-limit occurs when node i is affected separately by wind energy turbine set j.If node i voltage allows intermediate value V _i ⁰for the intermediate value of node voltage permission range of operation.?

${{\mathrm{<figure-callout\; id="0"\; label="V\; i"\; filenames="120530094529.png,120530094531.png"\; state="\{\{state\}\}">V</figure-callout>}}_i}^0=\frac{1}{2}(V_{\mathrm{iMin}}+V_{i\max })$

In formula, V _imaxnode i voltage allows the upper limit and V _iminnode i voltage allows lower limit.

When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be greater than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

In formula, n _jfor wind energy turbine set j blower fan number, referring to will

substitution (4) in P calculate,

referring to will p in substitution (4) calculates;

When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be less than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

In formula,

referring to will

substitution (4) in P calculate, referring to will

p in substitution (4) calculates;

Therefore, the overall voltage out-of-limit probability β of node i _ifor

${\mathrm{\&beta;}}_i=\frac{K_i}{n_W}\underset{j\&Element;W}{\mathrm{\&Sigma;}}\frac{{\mathrm{\&beta;}}_{\mathrm{ij}}}{K_{\mathrm{ij}}}$

(3) taking the weighted sum of network loss and the out-of-limit maximum probability value of node voltage as target function, with power flow equation constraint, the constraint of node voltage range of operation, the range constraint of exerting oneself that reactive power source is idle, the range constraint of transferring the files of the idle units limits of reactive-load compensation equipment and transformer be constraints build based on voltage out-of-limit probability containing wind energy turbine set idle work optimization model.

The wind energy turbine set reactive power optimization model that contains based on voltage out-of-limit probability comprises target function and constraints two parts.

The target function containing wind energy turbine set reactive power optimization model based on voltage out-of-limit probability is

$\min f={\mathrm{\&omega;}}_1{P}_L+{\mathrm{\&omega;}}_2\underset{i\&Element;N}{\mathrm{Max}}{\mathrm{\&beta;}}_i$

In formula, P _lfor network loss, represent to solve the maximum of all node overall situation voltage out-of-limit probability.ω ₁, ω ₂for weight coefficient, span is 0 ~ 1, generally gets ω ₁be 0.2, ω ₂be 0.8.Network loss P _lcomputational methods be

$P_L=\underset{i\&Element;N,j\&Element;N}{\mathrm{\&Sigma;}}{\left|\frac{V_i-V_j}{r_{\mathrm{oij}}+x_{\mathrm{Loij}}}\right|}^2\frac{r_{\mathrm{oij}}}{L_{\mathrm{ij}}}$

In formula, V _iand V _jbe respectively the voltage of i node and j node.R _oijfor circuit unit resistance, x between node i and node j _loijfor the circuit unit's reactance between node i and node j, L _ijfor the line length between node i and node j.

The constraints containing wind energy turbine set reactive power optimization model based on voltage out-of-limit probability is power flow equation constraint, the constraint of node voltage allowed band, generator reactive exert oneself range constraint, the idle units limits of reactive-load compensation equipment and the range constraint of transferring the files of transformer.

(4) adopt genetic algorithm for solving based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization model, automatic voltage control system, according to the control command of sending reactive apparatus based on the solving result containing wind energy turbine set reactive power optimization model of voltage out-of-limit probability, is controlled the action of reactive apparatus.Genetic algorithm is a kind of intelligent search algorithm of conventional solving-optimizing model optimal solution.

Be below an example of calculation shows of the inventive method, taking 2011, domestic certain city A 110kV and above upper strata electrical network carried out simulation calculation as example.

Fig. 1 has reflected the idiographic flow containing wind energy turbine set reactive power optimization based on voltage out-of-limit probability.Concrete implementation step is as follows:

1) gather the operation of power networks parameter of city A electrical network, the long-time section of the blower foundation parameter of wind energy turbine set Y and wind energy turbine set Y meritorious go out force data.

2), by operation of power networks calculation of parameter electric network swim, obtain local voltage factor of influence K _ij, and then obtain overall voltage influence factor K _i.The power conversion coefficient C of the blower foundation calculation of parameter blower fan by wind energy turbine set Y _p.By wind energy turbine set Y meritorious go out force data and least square fitting ask for the parameter of the meritorious probability distribution equation of wind energy turbine set Y;

3) taking the weighted sum of network loss and the out-of-limit maximum probability value of node voltage as target function, with power flow equation constraint, the constraint of node voltage range of operation, the range constraint of exerting oneself that reactive power source is idle, the range constraint of transferring the files of the idle units limits of reactive-load compensation equipment and transformer be constraints build based on voltage out-of-limit probability containing wind energy turbine set idle work optimization model.

4) adopt genetic algorithm for solving based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization model, automatic voltage control system, according to the control command of sending reactive apparatus based on the solving result containing wind energy turbine set reactive power optimization model of voltage out-of-limit probability, is controlled the action of reactive apparatus.

Fig. 2 has shown the power network topology of city A, only comprises a wind energy turbine set Y in electrical network.Operation of power networks parameter mainly gathers large mode operational factor in its summer.Because number of parameters is huge, within the rule go out.

By the grid-connected protocol requirement of wind energy turbine set Y, wind energy turbine set Y is with the power factor operation of constant hysteresis 0.95.Calculate through twice trend, calculate the voltage influence factor of the each node of city A electrical network.

The blower foundation parameter of the wind energy turbine set Y collecting is

Table 1 MY1.5s fan parameter

Getting atmospheric density is under an atmospheric pressure, the atmospheric density 20 degrees Celsius time, i.e. 1.205kg/m3.Can be calculated C _pbe about 0.4912.

Fig. 3 shown wind energy turbine set Y2011 110 days totally 31304 sampled points (5 minutes sampled points) meritorious go out force data.

Fig. 4 has shown the result that adopts the meritorious probability distribution equation of wind energy turbine set and least square fitting.In figure, dotted line is wind energy turbine set Y gain merit the actual probability distribution of force data, and solid line is fitting result.Fitting result: dimensional parameters c is 10.818, form parameter k is 2.842.

Weight coefficient ω ₁, ω ₂get respectively 0.2,0.8.The target function of the idle work optimization model containing wind energy turbine set city A electrical network based on voltage out-of-limit probability is

$\min f=0.2P_L+0.8\underset{i\&Element;N}{\mathrm{Max}}{\mathrm{\&beta;}}_i$

In formula, P _lfor city A network loss,

represent to solve the maximum of all node overall situations of city A electrical network voltage out-of-limit probability.Meanwhile, this model is with power flow equation constraint, the constraint of node voltage range of operation, the range constraint of exerting oneself that reactive power source is idle, and the range constraint of transferring the files of the idle units limits of reactive-load compensation equipment and transformer is constraints.

The voltage of the 110kV electrical network before Fig. 5 a and Fig. 5 b have shown respectively optimal control and after optimal control distributes.The node voltage of 100kV electrical network allows the upper limit and node voltage to allow lower limit to be respectively 106.7kV and 117.7kV.Visible, after idle work optimization, do not have voltage to occur out-of-limit, idle work optimization has ensured quality of voltage well.

The contrast of other two item numbers certificates is

The contrast of table 2 result

From table 2, the Y network loss 3.85%(that declined in city is 1.05MW), can be the remaining a lot of costs of operation of power networks.Meanwhile, overall voltage out-of-limit probability average has declined 99.15%, illustrates that optimum results more can adapt to fluctuation and the intermittence of wind energy turbine set power.

The overall voltage out-of-limit probability of all 110kV nodes before Fig. 6 a and Fig. 6 b have shown city Y optimal control successively and after optimal control.Visible, before optimization, there is quite a few node to occur voltage out-of-limit (the overall voltage out-of-limit probability of node is greater than 1); And fluctuation and intermittent impact (the overall voltage out-of-limit probability of node is greater than 0) that after optimizing, nearly all 110kV node is not subject to wind energy turbine set power completely only have 1 110kV node wind-engaging film to ring.

Can be proved by above execution mode example, based on voltage out-of-limit probability not only can be ensureing in quality of voltage to reduce grid net loss containing wind energy turbine set reactive power optimization method, reduce operation of power networks cost, can also improve fluctuation and the intermittent adaptability of grid nodes voltage to wind energy turbine set power.

Claims (6)

1. Based on voltage out-of-limit probability containing a wind energy turbine set reactive power optimization method, it is characterized in that comprising the following steps:

   (1) gather the blower foundation parameter of operation of power networks parameter, each wind energy turbine set and the long-time section of wind energy turbine set meritorious go out force data; Operation of power networks parameter comprises: power network topology, line parameter circuit value, transformer station's parameter, load parameter, generator parameter, node voltage allow range of operation, reactive-load compensation equipment parameter, node serial number set N and wind energy turbine set numbering set W; Power network topology refers to the connected mode of circuit and circuit, circuit and transformer in electrical network, and the line parameter circuit value of each circuit comprises circuit unit resistance r _o, the reactance x of circuit unit _lo, the susceptance X of circuit unit _cowith line length L; Transformer station's parameter comprises transformer number n _t, the equivalent resistance r of each transformer _t, equivalent reactance x _t, transformer equivalent no-load voltage ratio k _t, no-load voltage ratio upper limit k _maxwith no-load voltage ratio lower limit k _min; The load parameter of each node includes workload P _lNwith load or burden without work Q _lN; Generator parameter comprises as the active power of traditional power plant of PV node and voltage, as the active power of traditional power plant of PQ node and reactive power and as voltage and the phase angle of traditional power plant of V θ node; Node voltage allowed band comprises that node voltage allows upper limit V _maxallow lower limit V with node voltage _min; Reactive-load compensation equipment parameter comprises that the capacitor group of each node counts n _cwith every pool-size n _co, each node Reactor banks count n _lwith every pool-size n _lo; The underlying parameter of each wind electric field blower comprises the rated power P of blower fan _n, incision wind speed v _in, cut-out wind speed v _out, rated wind speed v _nwith wind sweeping area A;

   (2) by operation of power networks calculation of parameter electric network swim, obtain the voltage influence factor, i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i; Calculate the power conversion coefficient C of blower fan by the underlying parameter of blower fan _p; By wind energy turbine set meritorious go out force data and least square fitting obtain dimensional parameters c and the form parameter k of the meritorious probability distribution equation of wind energy turbine set; Local voltage factor of influence K _ijwith overall voltage influence factor K _i, blower fan power conversion coefficient C _pbe used for computing node voltage out-of-limit probability with meritorious probability distribution equation;

   (3) taking the weighted sum of network loss and the out-of-limit maximum probability value of node voltage as target function, taking power flow equation, node voltage range of operation, reactive power source is idle exert oneself that scope, reactive-load compensation equipment idle exerted oneself and the scope of transferring the files of transformer as constraints build based on voltage out-of-limit probability containing wind energy turbine set idle work optimization model;

   (4) adopt genetic algorithm for solving based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization model, automatic voltage control system, according to the control command of sending reactive apparatus based on the solving result containing wind energy turbine set reactive power optimization model of voltage out-of-limit probability, is controlled the action of reactive apparatus.
2. According to claim 1 based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method, it is characterized in that: the described voltage influence factor refers to the influence degree of wind energy turbine set to a certain grid nodes voltage, the voltage influence factor is divided two kinds: i.e. local voltage factor of influence K _ijwith overall voltage influence factor K _i, both passes are

   $K_i=n_W/\left(\underset{j\&Element;W}{\mathrm{\&Sigma;}}\frac{1}{K_{\mathrm{ij}}}\right)---\left(1\right)$

   Local voltage factor of influence K _ijfor wind energy turbine set j, j is an element of wind energy turbine set numbering set W, under independent role, cause per unit node i, i is an element of node serial number set N, the active power variable quantity of the required wind energy turbine set j of voltage variety, each wind energy turbine set is carried out to twice trend calculating, the operation of power networks parameter that twice trend calculated remains unchanged, and calculates for the first time zero of wind energy turbine set, calculates for the second time that wind energy turbine set is completely sent out and with given hysteresis firm power factor operation, local voltage factor of influence K _ijcomputational methods be

   $K_{\mathrm{ij}}=\frac{P_{\mathrm{jN}}}{{\mathrm{\&Delta;V}}_{\mathrm{ijMax}}}---\left(2\right)$

   In formula, P _jNfor the installed capacity of wind energy turbine set j; Δ V _ijMaxfor the voltage variety of twice trend calculating of node i,

   Overall situation voltage influence factor K _irefer to simultaneously under all wind energy turbine set affect, cause total active power variable quantity of the required all wind energy turbine set of per unit node i voltage variety.
3. According to claim 1 based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method, it is characterized in that: described power conversion coefficient C _prefer to the ratio of blower fan electromagnetic power and wind wheel mechanical output, obtained by following formula estimation,

   $C_p=\frac{{2P}_N}{{\mathrm{\&rho;Av}}_N^3}---\left(3\right).$
4. According to claim 1 based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method, it is characterized in that: the meritorious probability distribution equation of described wind energy turbine set is

   $\mathrm{\&beta;}\left(P\right)=\left\{\begin{array}{cc}1-\exp [-{\left(\frac{v_{\mathrm{in}}}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)}^k]& (0\&le;P<P_1)\\ 1-\exp [-{\left(\frac{v_p}{c}\right)}^k]+\exp [-{\left(\frac{v_{\mathrm{out}}}{c}\right)}^k]& (P_1\&le;P<P_N)\\ 1& (P=P_N)\end{array}\right.----\left(4\right)$

   In formula, meritorious the exerting oneself that P is blower fan; P ₁for wind speed is v _inthe meritorious of Shi Fengji exerted oneself; v _pfor being less than rated power and being greater than P as the meritorious P that exerts oneself of blower fan ₁meritorious wind speed corresponding to P of exerting oneself of Shi Fengji, v _pcomputational methods be

   $v_p=\sqrt[3]{\frac{2P}{C_P\mathrm{A\&rho;}}}---\left(5\right)$

   In formula, C _pfor the power conversion coefficient of blower fan, ρ is the atmospheric density of wind wheel hub At The Height, and A is wind wheel wind sweeping area.
5. According to claim 4 based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method, it is characterized in that: described voltage out-of-limit probability refers under steady state condition, in a control cycle of automatic voltage control system, there is out-of-limit probability in the node voltage of electrical network wind-engaging electric field influence, voltage out-of-limit probability divides two kinds: the out-of-limit probability β of local voltage _ijwith overall voltage out-of-limit probability β _i;

   The out-of-limit probability β of local voltage _ijrefer to the probability that voltage out-of-limit occurs when node i is affected separately by wind energy turbine set j, establish node i voltage and allow intermediate value V _i ⁰for the intermediate value of node voltage permission range of operation,

   ${V_i}^0=\frac{1}{2}(V_{\mathrm{iMin}}+V_{i\max })---\left(6\right)$

   In formula, V _imaxnode i voltage allows the upper limit and V _iminnode i voltage allows lower limit;

   When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be greater than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

   

   in formula, n _jfor wind energy turbine set j blower fan number,

   

   referring to will substitution (4) in P calculate,

   

   referring to will

   

   p in substitution (4) calculates;

   When node i voltage allows upper limit V _iMaxvoltage variety Δ V with twice trend calculating of node i _ijMaxabsolute difference be less than node i voltage and allow intermediate value V _i ⁰time, the out-of-limit probability β of local voltage _ijfor

   

   in formula,

   

   referring to will

   

   substitution (4) in P calculate,

   

   referring to will

   

   p in substitution (4) calculates;

   Therefore, the overall voltage out-of-limit probability β of node i _ifor

   ${\mathrm{\&beta;}}_i=\frac{K_i}{n_W}\underset{j\&Element;W}{\mathrm{\&Sigma;}}\frac{{\mathrm{\&beta;}}_{\mathrm{ij}}}{K_{\mathrm{ij}}}---\left(9\right).$
6. According to claim 1 based on voltage out-of-limit probability containing wind energy turbine set reactive power optimization method, it is characterized in that: described based on voltage out-of-limit probability comprise target function and constraints two parts containing wind energy turbine set reactive power optimization model,

   The target function containing wind energy turbine set reactive power optimization model based on voltage out-of-limit probability is

   $\min f={\mathrm{\&omega;}}_1{P}_L+{\mathrm{\&omega;}}_2\underset{i\&Element;N}{\mathrm{Max}}{\mathrm{\&beta;}}_i---\left(10\right)$

   Wherein, P _lfor network loss;

   

   represent to solve the maximum of all node overall situation voltage out-of-limit probability; ω ₁, ω ₂for weight coefficient, span is 0～1, network loss P _lcomputational methods be

   $P_L=\underset{i\&Element;N,j\&Element;N}{\mathrm{\&Sigma;}}{\left|\frac{V_i-V_j}{r_{\mathrm{oij}}+x_{\mathrm{Loij}}}\right|}^2\frac{r_{\mathrm{oij}}}{L_{\mathrm{ij}}}---\left(11\right),$

   In formula, V _iand V _jbe respectively the voltage of i node and j node; r _oijfor circuit unit resistance, x between node i and node j _loijfor the circuit unit's reactance between node i and node j, L _ijfor the line length between node i and node j.

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