CN104795825B - Asynchronous Reactive Compensation in Wind Farm place capacity collocation method under electric network fault - Google Patents

Abstract

The invention discloses asynchronous Reactive Compensation in Wind Farm place capacity collocation method under a kind of electric network fault, A) calculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that the minimum PCC point voltage of Grid code low voltage crossing requirement；B) calculate and the minimum corresponding capacity of reactive power compensation device of PCC point voltage；The configuration of asynchronous Reactive Compensation in Wind Farm place capacity is not less than this lowest capacityS _C .This collocation method can be calculated the reactive-load compensation equipment capacity minima of the required installing of asynchronous wind energy turbine set PCC point when disclosure satisfy that low voltage crossing requirement in Grid code, it is applicable to the planning of existing grid-connected asynchronous Reactive Compensation in Wind Farm place capacity, can be that actual asynchronous wind energy turbine set carries out reactive-load compensation equipment capacity configuration offer reference, it is effectively improved the low feasibility wearing modification scheme of actual asynchronous wind energy turbine set and economy, is conducive to improving the low voltage ride-through capability of wind energy turbine set and the Enhancement of Transient Voltage Stability of the regional power grid containing asynchronous wind energy turbine set.

Description

Asynchronous Reactive Compensation in Wind Farm place capacity collocation method under electric network fault

Technical field

The present invention relates to the reactive-load compensation equipment capacity configuration field of the asynchronous wind energy turbine set of Large Copacity, particularly to for electrical network The asynchronous Reactive Compensation in Wind Farm installed capacity collocation method that in directive/guide, low voltage crossing requires.

Background technology

New wind farm grid-connected directive/guide " GB/T 19,963 2011 wind energy turbine set accesses power system technology regulation " proposes " when wind farm grid-connected point voltage falls to 20% nominal voltage, the Wind turbines in wind energy turbine set should ensure that off-grid does not runs continuously 625ms " strict demand.For the uncontrollability of the tradition asynchronous Wind turbines of constant speed, Chinese scholars proposes at asynchronous wind Electric field PCC point (wind energy turbine set points of common connection, point ofcommon coupling are called for short PCC point) installing reactive-load compensation equipment Low voltage crossing modification scheme to assist it to complete fault traversing.The low voltage crossing of wind energy turbine set asynchronous for constant speed type changes Make, reactive-load compensation equipment capacity be arranged in feasibility and the economy determining transformation to a certain extent.At present, for asynchronous The existing following open source literature of the reactive-load compensation equipment capacity collocation method of wind energy turbine set:

(1) Zhu Xueling, Zhang Yang, Gao Kun, etc. the research [J] of Reactive Compensation in Wind Farm problem. protecting electrical power system and control System, 2009,37 (16): 68-72.

(2) Liu Peijin, Gu Lichen. the power system reactive power plan optimization [J] containing wind energy turbine set. electric power network technique, 2010,34 (7):175-180.

(3)Philippe Maibach,Carsten Ritter,Mohamed Saleh,et al.STATCOM size optimization through wind turbine operation with fixed power factor[C] .Proceedings of the 2011-14th European Conference on Power Electronics andApplications,2011:1-11.

The reactive compensation capacity of wind energy turbine set is configured and has done theoretic discussion by document (1), and proposing wind energy turbine set should be according to it During steady-state operation, required reactive power determines its reactive-load compensation equipment capacity.Document (2) proposes to save energy loss expense The method being the reactive-load compensation equipment optimal allocation capacity of target to the maximum.Document (3) then proposes by keeping asynchronous wind energy turbine set PCC Point power factor is definite value rather than the unity power factor method of operation can reduce the configuration capacity of STATCOM reactive-load compensation equipment, And the method proposing to determine STATCOM configuration capacity according to Q-U curve.Although more than research can be asynchronous wind energy turbine set steady-state operation The determination of period reactive-load compensation equipment capacity configuration provides foundation, but is all not directed to the idle of asynchronous wind energy turbine set transient state run duration Compensate the allocation problem of place capacity.

Summary of the invention

For existing collocation method above shortcomings, it is an object of the invention to propose one based on asynchronous wind energy turbine set The capacity collocation method of asynchronous Reactive Compensation in Wind Farm equipment under the electric network fault of parameter, this collocation method can calculate asynchronous wind-powered electricity generation In field satisfied " GB/T 19,963 2011 wind energy turbine set accesses power system technology regulation ", " wind farm grid-connected point voltage falls to 20% During nominal voltage, the Wind turbines in wind energy turbine set should ensure that off-grid does not runs 625ms continuously " require the required reactive-load compensation configured Place capacity minima.

The technical scheme is that and be achieved in that:

Asynchronous Reactive Compensation in Wind Farm place capacity collocation method under electric network fault, step is as follows,

A) calculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that the minimum PCC point of Grid code low voltage crossing requirement Voltage；

A1) according to the wind energy turbine set low voltage crossing of " GB/T 19,963 2011 wind energy turbine set accesses power system technology and specifies " Require to calculate the breakdown slip s of asynchronous wind energy turbine set_cr；

A2) by A1) gained breakdown slip s_crCalculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that Grid code is low The minimum PCC point voltage U that voltage ride-through requires_PCCmin, it is shown below:

$U_{\mathrm{PCC}\min }=\sqrt{\frac{T_m{\mathrm{\Ω}}_s\{{[R_L+c_2(R_1+c_1{R}_2^{\′}/s_{\mathrm{cr}})]}^2+{[X_L+X_T+c_2(X_{1\mathrm{\σ}}+c_1{X}_{2\mathrm{\σ}}^{\′})]}^2\}}{m_1\·R_2^{\′}/s_{\mathrm{cr}}}}$

In formula: m₁For the stator winding number of phases；Ω_sFor synchronous angular velocity；T_mFor machine torque；R₁, X_1σIt is respectively stator resistance And stator leakage reactance；R₂', X_2σ' it is respectively the rotor resistance after converting and rotor leakage reactance；R_L, X_LBe respectively wind energy turbine set and and site between Line resistance and reactance；X_TFor wind farm side booster transformer short-circuit reactance；c₁=1+X_1σ/X_m, for correction factor；c₂=1+ (X_L +X_T)/X_C//m；X_C//m=X_CX_m/(X_C+X_m), for X_CWith X_mParallel value；X_m, X_CIt is respectively excitatory reactance and machine end shunt reactor Capacitive reactance；

B) calculate and the minimum corresponding capacity of reactive power compensation device of PCC point voltage；

B1) by A1) gained breakdown slip s_crAnd A2) gained minimum PCC point voltage U_PCCminCalculate the fault recovery initial stage The active-power P that asynchronous wind energy turbine set sends to electrical network_FSIGWith the reactive power Q absorbed_FSIG；

B2) by A2) gained U_PCCmin, B1) gained P_FSIGAnd Q_FSIGCalculate fault recovery initial stage asynchronous wind energy turbine set trend, obtain Fault recovery initial stage asynchronous wind energy turbine set disclosure satisfy that the PCC point reactive-load compensation equipment of Grid code low voltage crossing requirement is required and sends out Go out reactive power Q_C:

$Q_C=Q_{\mathrm{FSIG}}-\frac{U_{\mathrm{PCC}\min }(U_g-U_{\mathrm{PCC}\min })+P_{\mathrm{FSIG}}{R}_L}{X_L+X_T}$

B3) by B2) gained Q_CWith A2) gained U_PCCminIt is divided by and i.e. obtains reactive-load compensation equipment lowest capacity S_C: asynchronous wind-powered electricity generation Field reactive-load compensation equipment capacity configuration is not less than this lowest capacity S_C?；

$S_C=\frac{Q_C}{U_{\mathrm{PCC}\min }}$

Compared to existing technology, there is advantages that

This collocation method can be calculated asynchronous wind energy turbine set PCC point when disclosure satisfy that low voltage crossing requirement in Grid code The reactive-load compensation equipment capacity minima of required installing, it is adaptable to existing grid-connected asynchronous Reactive Compensation in Wind Farm place capacity is advised Draw, can be that actual asynchronous wind energy turbine set carries out reactive-load compensation equipment capacity configuration offer reference, be effectively improved actual asynchronous wind energy turbine set The low feasibility wearing modification scheme and economy, be conducive to improving the low voltage ride-through capability of wind energy turbine set and containing asynchronous wind energy turbine set The Enhancement of Transient Voltage Stability of regional power grid.

Accompanying drawing explanation

Fig. 1 is asynchronous Reactive Compensation in Wind Farm place capacity collocation method flow chart under electric network fault of the present invention.

Fig. 2 is the Large Copacity asynchronous wind energy turbine set topology diagram (C in figure that parallel reactive compensates equipment₁For machine end parallel connection electricity Container, T₁For machine end booster transformer, Z₁For circuit between wind energy turbine set and PCC point, T is that wind energy turbine set exports booster transformer, Z_LFor wind Circuit between electric field PCC point and infinitely great electrical network, Grid is infinitely great electrical network).

Fig. 3 is Large Copacity asynchronous wind energy turbine set trend topological diagram (Q in figure_CReactive power is sent out) by reactive-load compensation equipment.

Asynchronous wind energy turbine set simulation result figure under the conditions of electric network fault when Fig. 4 is critical compensation.

Detailed description of the invention

Below in conjunction with calculated examples and accompanying drawing, specific embodiments of the present invention are described in detail.

In conjunction with calculation process shown in Fig. 1, the capacity collocation method of asynchronous Reactive Compensation in Wind Farm equipment under electric network fault It is embodied as step as follows:

(A) wind energy turbine set and connected operation of power networks parameter are gathered:

In this example, wind energy turbine set is composed in parallel by the asynchronous Wind turbines of constant speed that 30 separate unit rated power is 1MW, system Topological structure is as shown in Figure 2.Asynchronous machine machine end exit potential is 0.69kV, links wind energy turbine set through 0.69/35kV transformator Internal electric network, after 2km transmission line of electricity accesses 35/110kV booster stations, accesses local 110kV electricity by 100km transmission line of electricity Net, reactive-load compensation equipment is connected on 35/110kV booster stations low-pressure side bus, i.e. wind energy turbine set points of common connection.Wherein line parameter circuit value Z₁ =0.17+j0.38 Ω/km, Z_L=0.1153+0.3299 Ω/km, transformator is as shown in table 1 with non-synchronous motor parameter.

Table 1 transformator and asynchronous wind energy turbine set parameter

(B) calculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that the minimum PCC of Grid code low voltage crossing requirement Point voltage:

B1) by relational expression between the asynchronous machine equation of motion and revolutional slip and rotor mechanical angle speed:

$J\frac{\mathrm{d\ω}}{\mathrm{dt}}=T_m-T_e---\left(1\right)$

$s=\frac{{\mathrm{\ω}}_s-\mathrm{\ω}}{{\mathrm{\ω}}_s}---\left(2\right)$

Obtain asynchronous machine critical clearing time expression formula:

$T_{\mathrm{CCT}}=-J{\mathrm{\ω}}_s{\∫}_{s_N}^{s_{\mathrm{cr}}}\frac{1}{T_m-T_e}\mathrm{ds}---\left(3\right)$

Wherein J is rotary inertia；s_NRated motor runs slip；T_mFor machine torque；Te is electromagnetic torque；By asynchronous electricity Machine operational factor J, s_N、T_m, the grid-connected point voltage asynchronous wind energy turbine set Te-s characteristic equation when dropping to 20% and " GB/ T19963 2011 wind energy turbine set accesses power system technology regulation " the middle asynchronous wind energy turbine set critical clearing time 625ms band required Enter formula (3), be met the asynchronous wind energy turbine set breakdown slip s of Grid code low voltage crossing requirement_cr。

B2) by B1) gained breakdown slip s_crCalculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that Grid code is low The minimum PCC point voltage U that voltage ride-through requires_PCCmin, it is shown below:

$U_{\mathrm{PCC}\min }=\sqrt{\frac{T_m{\mathrm{\Ω}}_s\{{[R_L+c_2(R_1+c_1{R}_2^{\′}/s_{\mathrm{cr}})]}^2+{[X_L+X_T+c_2(X_{1\mathrm{\σ}}+c_1{X}_{2\mathrm{\σ}}^{\′})]}^2\}}{m_1\·R_2^{\′}/s_{\mathrm{cr}}}}---\left(4\right)$

In formula: m₁For the stator winding number of phases；Ω_sFor synchronous angular velocity；T_mFor machine torque；R₁, X_1σIt is respectively stator resistance And stator leakage reactance；R₂', X_2σ' it is respectively the rotor resistance after converting and rotor leakage reactance；R_L, X_LBe respectively wind energy turbine set and and site between Line resistance and reactance；X_TFor wind farm side booster transformer short-circuit reactance；c₁=1+X_1σ/X_m, for correction factor；c₂=1+ (X_L +X_T)/X_C//m；X_C//m=X_CX_m/(X_C+X_m), for X_CWith X_mParallel value；X_m, X_CIt is respectively excitatory reactance and machine end shunt reactor Capacitive reactance；

(C) calculate and the minimum corresponding capacity of reactive power compensation device of PCC point voltage:

C1) by B1) gained breakdown slip s_crAnd B2) gained minimum PCC point voltage U_PCCminCalculate the fault recovery initial stage The active-power P that asynchronous wind energy turbine set sends to electrical network_FSIGWith the reactive power Q absorbed_FSIG。

$\left\{\begin{array}{c}{P}_{\mathrm{FSIG}}={U_{\mathrm{PCC}\min }}^2\frac{R_{\mathrm{PCC}}}{R_{\mathrm{PCC}}^2+X_{\mathrm{PCC}}^2}\\ Q_{\mathrm{FSIG}}={U_{\mathrm{PCC}\min }}^2\frac{X_{\mathrm{PCC}}}{R_{\mathrm{PCC}}^2+X_{\mathrm{PCC}}^2}\end{array}\right.---\left(5\right)$

R in formula_PCCAnd X_PCCIt is respectively substitutional resistance and the inductance of asynchronous wind farm grid-connected point.

C2) by B2), C1) gained U_PCCmin、P_FSIGAnd Q_FSIGCalculate fault recovery initial stage asynchronous wind energy turbine set trend, wind energy turbine set Trend topology is as it is shown on figure 3, obtain fault recovery initial stage asynchronous wind energy turbine set to disclosure satisfy that Grid code low voltage crossing requirement Reactive power Q is sent needed for PCC point reactive-load compensation equipment_C:

$Q_C=Q_{\mathrm{FSIG}}-\frac{U_{\mathrm{PCC}\min }(U_g-U_{\mathrm{PCC}\min })+P_{\mathrm{FSIG}}{R}_L}{X_L+X_T}---\left(6\right)$

C3) by C2) gained reactive power Q_CWith B2) gained minimum PCC point voltage U_PCCminIt is divided by and i.e. obtains reactive-load compensation and set Standby lowest capacity S_C: the configuration of asynchronous Reactive Compensation in Wind Farm place capacity is not less than this lowest capacity S_C?.

$S_C=\frac{Q_C}{U_{\mathrm{PCC}\min }}---\left(7\right)$

Result of calculation shows, when in this example, asynchronous wind energy turbine set can complete electric network fault, reactive power compensator need to provide nothing Merit power 9.08Mvar, its capacity is 10.42MVA.Fig. 4 is critical benefit for using emulation repeatedly to arrange reactive-load compensation installing capacity Repay the simulation result of asynchronous wind power system fault traversing during capacity.Simulation result shows that asynchronous wind energy turbine set can complete electric network fault Time, reactive power compensator need to provide reactive power 7.63Mvar, and its capacity is 9.61MVA.Can with simulation result contrast by calculating See, use the capacity collocation method of asynchronous Reactive Compensation in Wind Farm equipment under electric network fault proposed by the invention, can be actual Asynchronous wind energy turbine set carries out reactive-load compensation equipment capacity configuration provides reference, is effectively improved that actual asynchronous wind energy turbine set is low wears modification scheme Feasibility and economy, be conducive to improving the low voltage ride-through capability of wind energy turbine set and regional power grid temporary containing asynchronous wind energy turbine set State voltage stability.

Last it should be noted that above example is only in order to illustrate technical scheme and unrestricted, although Shen Ask someone with reference to preferred embodiment, the present invention to be described in detail, it will be understood by those within the art that, to this Bright technical scheme is modified or equivalent, without deviating from objective and the scope of the technical program, all should contain at this In the middle of the right of invention.

Claims (1)

1. asynchronous Reactive Compensation in Wind Farm place capacity collocation method under electric network fault, it is characterised in that: step is as follows,

A) calculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that the minimum PCC point electricity of Grid code low voltage crossing requirement Pressure；

A1) require to calculate the breakdown slip s of asynchronous wind energy turbine set according to wind energy turbine set low voltage crossing_cr；

A2) by A1) gained breakdown slip s_crCalculate fault recovery initial stage asynchronous wind energy turbine set and disclosure satisfy that Grid code low-voltage Pass through the minimum PCC point voltage U of requirement_PCCmin, it is shown below:

$U_{\mathrm{PCC}\min }=\sqrt{\frac{T_m{\mathrm{\Ω}}_s\{{[R_L+c_2(R_1+c_1{R}_2^{\′}/s_{\mathrm{cr}})]}^2+{[X_L+X_T+c_2(X_{1\mathrm{\σ}}+c_1{X}_{2\mathrm{\σ}}^{\′})]}^2\}}{m_1\·R_2^{\′}/s_{\mathrm{cr}}}}$

In formula: m₁For the stator winding number of phases；Ω_sFor synchronous angular velocity；T_mFor machine torque；R₁, X_1σIt is respectively stator resistance and determines Sub-leakage reactance；R₂', X_2σ' it is respectively the rotor resistance after converting and rotor leakage reactance；R_L, X_LIt is respectively wind energy turbine set and also top-stitching road, site Resistance and reactance；X_TFor wind farm side booster transformer short-circuit reactance；c₁=1+X_1σ/X_m, for correction factor；c₂=1+ (X_L+X_T)/ X_C//m；X_C//m=X_CX_m/(X_C+X_m), for X_CWith X_mParallel value；X_m, X_CIt is respectively excitatory reactance and the appearance of machine end shunt reactor Anti-；

B) calculate and the minimum corresponding capacity of reactive power compensation device of PCC point voltage；

B1) by A1) gained breakdown slip s_crAnd A2) gained minimum PCC point voltage U_PCCminCalculate the fault recovery initial stage asynchronous The active-power P that wind energy turbine set sends to electrical network_FSIGWith the reactive power Q absorbed_FSIG；

B2) by A2) gained U_PCCmin, B1) gained P_FSIGAnd Q_FSIGCalculate fault recovery initial stage asynchronous wind energy turbine set trend, obtain fault Nothing is sent needed for the PCC point reactive-load compensation equipment that the asynchronous wind energy turbine set of initial stages of restoration disclosure satisfy that Grid code low voltage crossing requirement Merit power Q_C:

$Q_C=Q_{\mathrm{FSIG}}-\frac{U_{\mathrm{PCC}\min }(U_g-U_{\mathrm{PCC}\min })+P_{\mathrm{FSIG}}{R}_L}{X_L+X_T}$

B3) by B2) gained Q_CWith A2) gained U_PCCminIt is divided by and i.e. obtains reactive-load compensation equipment lowest capacity S_C: asynchronous wind energy turbine set without Merit compensates place capacity configuration and is not less than this lowest capacity S_C?；

$S_C=\frac{Q_C}{U_{\mathrm{PCC}\min }}.$