CN117578578A

CN117578578A - Method for identifying high-voltage ride through parameters of transient model of direct-drive wind turbine generator

Info

Publication number: CN117578578A
Application number: CN202311586068.8A
Authority: CN
Inventors: 李卫星; 金泳霖; 张凯; 晁璞璞; 朱天宇; 宋文婷
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2023-11-24
Filing date: 2023-11-24
Publication date: 2024-02-20

Abstract

A method for identifying high-voltage ride through parameters of a transient model of a direct-driven wind turbine belongs to the technical field of modeling and parameter identification of new energy power generation equipment of a power system. The method aims at solving the problem that at present, no method can be used for rapidly and finely modeling the electromechanical transient state of the direct-drive wind turbine generator in actual engineering. According to the method, the actually measured response data of all the test working conditions of the wind turbine generator in the high-voltage ride-through running state, the high-voltage ride-through recovery running state and the normal running state are utilized to perform parameter fitting on the combination control strategies in all the ride-through running state control submodules and the combination control strategies in all the recovery running state control submodules of the high-voltage ride-through running state to obtain control parameters under the combination control strategies in all the ride-through running state, then simulation verification is performed based on the control parameters, and further the control parameters are selected based on simulation results and response errors of the actually measured response data to complete parameter identification.

Description

Method for identifying high-voltage ride through parameters of transient model of direct-drive wind turbine generator

Technical Field

The invention belongs to the technical field of modeling and parameter identification of new energy power generation equipment of a power system, and particularly relates to a method for identifying high-voltage ride through parameters of a transient model of a direct-driven wind turbine.

Background

Under the guidance of the implementation of the 'double carbon' policy in China, the duty ratio of new energy sources represented by wind power in a power system is continuously increased. Wind energy is used as a part of new energy, and the wind power generation industry is rapidly developing due to the characteristics of wide distribution, abundant reserve and the like, and a power converter model of a wind power generation system is required to be researched in order to meet the grid-connected requirement of a wind power plant, so that the real working state of a fan under various working conditions is accurately represented. Therefore, a high-voltage ride-through model of the direct-drive power generation system is established through the fault ride-through dynamic characteristics of the direct-drive power generation system, model parameters capable of truly reflecting the output characteristics of the direct-drive power generation system are obtained, and accurate model parameters are obtained by adopting a parameter identification method, so that the dynamic response of the direct-drive power generation system is truly reflected, and the safe, stable and economic operation of the power system is ensured.

For electromechanical transient modeling of wind turbines, researchers have a variety of solutions, such as:

1. zhang Angfei et al, "electrical parameter identification of direct drive permanent magnet synchronous generators" power system automation, 2012, 36 (14): 150-153, the article analyzes the identifiability of each parameter under different working conditions according to a mathematical model of the direct-drive synchronous generator, and finally adopts a preferred initial value-micro-variation search algorithm to identify each parameter.

2. Huang Hua et al discloses a method for setting parameters of a direct-drive permanent magnet wind turbine LVRT model and actually measured verification electric power automation equipment, 2019, 39 (4): 155-160, the article calculates the sensitivity of each parameter by researching the model structure of the permanent magnet wind turbine, so that the key parameters of the low-voltage ride through model are obtained, the low-voltage ride through model of the direct-drive permanent magnet wind turbine is identified based on measured data by a parameter adjustment and optimization method, and the effectiveness of the method is verified by actual measurement and simulation comparison.

3. Wu Zhang et al, "MDPSO-based permanent magnet direct drive wind turbine parameter identification" electrical measurement and instrumentation, 2021, 58 (08): 83-87, the article provides an improved particle swarm algorithm for solving the problems of multi-parameter identification of a direct-drive wind turbine and poor precision of a traditional identification method, establishes a model of the direct-drive wind turbine by means of reduction and discretization, and effectively identifies parameters of the direct-drive wind turbine.

The conventional method is basically used for identifying key parameters in a wind turbine generator simulation model by improving a conventional mature optimization algorithm, cannot be mature and applied to PSASP simulation software adopted in the conventional domestic actual engineering, has complexity in the identification process, and does not have good universality. Therefore, a simple, efficient and general parameter identification method applicable to PSASP simulation software and aiming at high voltage ride through of a wind turbine generator is needed.

Disclosure of Invention

The method aims to solve the problem that at present, no method can be used for rapidly and finely modeling the electromechanical transient state of the direct-drive wind turbine generator in actual engineering.

A method for identifying high-voltage ride through parameters of a transient model of a direct-drive wind turbine generator comprises the following steps:

s1, parameter configuration is carried out on a transient model of a direct-drive wind turbine by using basic parameters obtained by a wind turbine specification and response data actually measured in the whole process of high voltage ride through under all test conditions;

s2, based on the high voltage ride through test model, adjusting fault point line voltage U corresponding to each test working condition in the high voltage ride through test model in the high voltage ride through period _{Fault_HVRT} To make the fault point line voltage U under each test working condition _{Fault_HVRT} The voltage is consistent with the actually measured fault point line voltage under the test working condition, and the fault point positive sequence voltage U under the test working condition during the high voltage crossing period is calculated by utilizing a high voltage crossing test model _{1_HVRT} ；

S3, according to the positive sequence voltage U of the fault point under the corresponding test working condition of not entering the high voltage crossing state _{1_HVRT} Obtaining a high voltage ride-through state judgment parameter VH _in And VH _out And VH is combined with _in And VH _out Assigning a value to the high voltage ride through test model; wherein VH _in To enter the high voltage crossing threshold, VH _out To exit the high voltage crossing threshold;

s4, performing parameter fitting on each in-pass combined control strategy of the in-pass operation state control submodule of the high-voltage-pass control submodule in the transient model of the direct-drive wind turbine generator by using actually measured response data of all test working conditions of the wind turbine generator in the high-voltage-pass operation state and in the normal operation state to obtain control parameters under each in-pass combined control strategy;

inputting the obtained control parameters into a high-voltage ride-through test model, so that the wind turbine generator performs simulation test on all test conditions under each ride-through combined control strategy, and simulation response data corresponding to all test conditions under the current ride-through combined control strategy is obtained;

s5, performing parameter fitting on each in-recovery combined control strategy of a high-voltage ride-through control sub-module in a transient model of the direct-drive wind turbine by using actually measured response data of all test working conditions of the wind turbine under the high-voltage ride-through recovery running state and the normal running state, so as to obtain control parameters under each in-recovery combined control strategy;

combining each combination control strategy in crossing with various combination control strategies in recovery to form a plurality of groups of high-voltage crossing control strategies; inputting the obtained control parameters into a high voltage ride through test model, and enabling the wind turbine generator to perform simulation test on all test conditions under each group of high voltage ride through control strategies to obtain simulation response data corresponding to all test conditions under the current high voltage ride through control strategies;

S6, calculating response errors between the high voltage ride through whole process simulation response data corresponding to all working conditions under each group of high voltage ride through control strategies and the actual measurement response data of the high voltage ride through whole process under the corresponding working conditions respectively to obtain a group of response errors; and selecting the component with the largest number of working conditions meeting the response error requirement and the smallest average response error from all the group response errors corresponding to the high-voltage ride-through control strategies of all the groups, and taking the control parameter corresponding to the component as the control parameter for controlling the transient model of the direct-drive wind turbine, thereby completing parameter identification.

Further, the basic parameters comprise the rated power of the generator, the rated rotating speed, the moment of inertia, the rated wind speed, the cut-in wind speed, the cut-out wind speed, the radius of the blade and the rated rotating speed of the wind turbine.

Further, the response data includes line voltage, active current, reactive current, active power, and reactive power at the point of failure.

Further, the high voltage ride through test model is as follows:

connecting current limiting impedance Z between high-voltage side of step-up transformer of wind turbine generator and external power grid _sr The bypass switch CB1 is connected with the current limiting impedance in parallel, and a boosting branch is connected between the current limiting impedance and the wind turbine generator set boosting transformer; the boost branch is formed by closing a short circuit switch CB3 and a boost branch capacitor C _L And a step-up resistor R _d Is formed by serial connection; the data measuring point is positioned on the high-voltage side of the step-up transformer of the wind turbine generator.

Further, in step S4, the individual control strategy in the high voltage ride through operation state control submodule in the high voltage ride through control submodule in the transient model of the direct-drive wind turbine generator set in the high voltage ride through operation state includes:

(1) The active current control mode of the wind turbine generator comprises the following steps:

(1) active current has no additional control: active current control strategy when the wind turbine generator is in normal operation is maintained;

(2) active power control is specified:

P _HVRT ＝K _P-HVRT *P ₀ +P _{set_HV} (3)

K _{P_HVRT} and P _{set_HV} All serve as control parametersA number;

wherein P is ₀ The active power of the wind turbine generator set in a normal running state is P _HVRT Active power K of wind turbine generator set in running state in high voltage ride through _{P_HVRT} Calculating coefficient for active power number 1, P _{set_HV} Setting the active power value;

(3) active current control is specified:

Ip _HVRT ＝K _1-Ip-HV *V _t +K _2-Ip-HV *Ip ₀ +Ip _{set_HV} (4)

K _{1_Ip_LV} 、K _{2_Ip_LV} and Ip _{set_LV} All are used as control parameters;

wherein Ip is ₀ The active current of the wind turbine generator set in a normal running state; ip (internet protocol) _HVRT The active current of the wind turbine generator set in the running state in the high voltage ride through is obtained; v (V) _t Positive sequence voltage value of the fan outlet; k (K) _{1-Ip_HV} Calculating a coefficient for active current No. 1; k (K) _{2_Ip_HV} Calculating a coefficient for active current No. 2; ip (internet protocol) _{set_HV} Setting the active current as an active current;

(4) active current control before push-through: the wind turbine generator system maintains active current at the moment before the wind turbine generator system enters high voltage ride through;

(2) The reactive current control mode of the wind turbine generator comprises the following steps:

(1) reactive current has no additional control: maintaining a reactive current control strategy when the wind turbine generator is in normal operation;

(2) designating reactive power control:

Q _HVRT ＝K _{Q_HVRT} *Q ₀ +Q _{set_HV} (5)

K _{Q_HVRT} and Q _{set_HV} All are used as control parameters;

wherein Q is ₀ Reactive power of wind turbine generator set in normal running state, Q _HVRT Reactive power of the wind turbine generator set in the running state in high voltage ride through; k (K) _{Q_HVRT} Calculate the coefficient for reactive power number 1, Q _{set_HV} Setting the reactive power;

(3) designating reactive current control;

Iq _HVRT ＝K _{1_Iq_HV} *(VH _in -V _t )+K _{2_Iq_HV} *Iq ₀ +Iq _{set_HV} (6)

K _{1_Iq_HV} 、K _{2_Iq_HV} 、Iq _{set_HV} and VH _in All are used as control parameters;

wherein Iq ₀ Reactive current of the wind turbine generator set in a normal running state; iq _HVRT Reactive current of the wind turbine generator set in the running state in high voltage ride through; v (V) _t Is positive sequence voltage value of fan outlet, K _{1_Iq_LV} Calculating a coefficient for reactive current No. 1; k (K) _{2_Iq_LV} Calculating a coefficient for reactive current No. 2; iq _set-HV Setting a reactive current value; VH (VH) _in To enter a high voltage ride through threshold;

(3) An asymmetric high voltage ride through current control scheme comprising:

(1) the control is performed according to a symmetrical fault processing mode: the symmetrical faults and the asymmetrical faults are not distinguished, and active and reactive currents are directly controlled according to an active current control mode and a reactive current control mode;

(2) Based on positive sequence voltage control:

K _1-Ip-HV-UBL 、K _2-Iq-HV-UBL 、Ip _{set_HV-UBL} 、K _{1_Iq_HV_UBL} 、K _2-Iq-HV-UBL and Iq _set-HV-UBL All are used as control parameters;

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _1-Ip-HV-UBL Calculating coefficient K for active current of No. 1 asymmetric fault _2-Ip-HV-UBL Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV-UBL} For the set value of the active current of the asymmetrical fault, K _1-Iq-HV-UBL Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _2-Iq-HV-UBL Calculating a coefficient for the asymmetric fault reactive current of No. 2; iq _{set_HV_UBL} Set value of reactive current for asymmetrical fault, V _t Is the positive sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

(3) negative sequence voltage control:

K _{1-Ip-HV_UBL} 、K _2-Iq-HV-UBL 、Ip _{set_HV-UBL} 、K _1-Iq-HV-UBL 、K _2-Iq-HV-UBL and Iq _set-HV-UBL All are used as control parameters;

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _1-Ip-HV-UBL Calculating coefficient K for active current of No. 1 asymmetric fault _2-Ip-HV-UBL Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV-UBL} For the set value of the active current of the asymmetrical fault, K _1-Iq-HV-UBL Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _2-Iq-HV-UBL Calculating a coefficient for the asymmetric fault reactive current of No. 2; iq _{set_HV_UBL} Set value of reactive current for asymmetrical fault, V _2t Is the negative sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

(4) correction control based on symmetrical fault current and negative sequence voltage:

K _{3_Ip_HV_UBL} 、K _{3_Iq_HV_UBL} as a control parameter;

wherein K is _{3_Ip_HV_UBL} Calculating coefficient K for active current of No. 3 asymmetric fault _{3_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 3;

combining the strategies, when the fault point is in a symmetrical fault, adopting one control mode of an active current control party of the wind turbine corresponding to the running state in the high voltage ride through and one control mode of a reactive current control party of the wind turbine corresponding to the running state in the high voltage ride through to form a ride through combined control strategy; when the fault point is in an asymmetric fault, one control mode of a current controller during the asymmetric high voltage ride-through period is adopted as a ride-through combined control strategy.

Further, in step S5, the individual control strategy in the high voltage ride through control sub-module in the transient model of the direct drive wind turbine generator in the high voltage ride through recovery operation state includes:

(1) The active current control mode for traversing the recovery starting point comprises the following specific control:

1a, active no additional control of crossing the recovery starting point: active current control strategy when the wind turbine generator system is in normal operation is maintained;

1b, controlling according to the initial active current percentage:

wherein Ip is _HVRSP Active current for crossing the recovery onset;is an initial active current percentage coefficient;to recover the starting active current set point;

1c, controlling according to active current during fault: active current of the wind turbine generator in the running state in high voltage ride through is maintained;

1d, active power control according to the fault period: the wind turbine generator system maintains active power in the running state in high voltage ride through, and converts active current according to the positive sequence voltage of the ride-through recovery starting point;

(2) The reactive current control mode of the crossing recovery starting point comprises the following specific control:

2a, no additional control is carried out on the reactive power of the traversing recovery starting point: the reactive current control strategy of the wind turbine generator system is maintained in normal operation;

2b, controlling according to the initial reactive current: controlling reactive current when the wind turbine generator runs normally;

2c, controlling according to the reactive current percentage during the fault:

wherein Iq _HVRSP Reactive current for traversing the recovery origin;the reactive current set value is recovered to the starting point;the reactive current percentage coefficient is used during faults;

2d, controlling according to the reactive power percentage during the fault:

wherein Q is _HVRTSP Reactive power for traversing the recovery origin;to recover the starting reactive power set point;the reactive power percentage coefficient is used during faults;

(3) Active power recovery control:

3a, active power recovery has no additional control: active power control strategy when the wind turbine generator system is in normal operation is maintained;

3b, active power recovery is controlled according to the slope:

P _HVRECO ＝min(P _HVRTRSP +K _{P_RECO} ·t,P ₀ ) (13)

wherein P is _HVRECO Active power during high voltage ride through recovery; p (P) _HVRTRSP Active power for recovering the starting point; k (K) _{P_RECO} Recovering a slope for active power; t is the high voltage ride through recovery time; p (P) ₀ The active power of the wind turbine generator set in a normal running state;

3c, active power recovery is controlled according to an inertia curve:

wherein T is _{P_RECO} Recovering an inertia constant for the active power;

(4) Reactive power recovery control:

4a, reactive power recovery has no additional control: the reactive power control strategy of the wind turbine generator system in normal operation is maintained;

4b, reactive power recovery is controlled according to an inertia curve:

wherein Q is _HVRECO Reactive power during high voltage ride through recovery; q (Q) _LVRTRSP To recover the starting reactive power; t (T) _{Q_RECO} Recovering an inertia constant for reactive power;

and combining the strategies, wherein each selected one of the specific control strategies contained in the 4 control modes is used as a combined control strategy in recovery, so that the control of the wind turbine generator in the high-voltage ride through recovery running state is realized together.

Further, the judgment of the high voltage crossing state in the step S3 that the high voltage crossing state is not entered is based on the following:

the reactive power output of the wind turbine generator system is suddenly reduced by more than 0.1p.u. and is considered to enter a high voltage ride through state.

Further, in step S3, the high voltage ride through state determination parameter VH _in ＝VH _out ＝U _{1_HVRT_max} +0.03p.u.。

Further, in the step S4 and the step S5, the curve fitting is performed by using a least square method.

Further, all working conditions in the step S6 are determined by the combination of the voltage rise of a fault point line, the wind speed and the fault type, wherein the voltage rise of the fault point line is at least 120%, 125% and 130%, the wind speed is at least high wind and low wind, the fault type is at least three-phase fault and two-phase fault, and the combination of the voltage rise of the fault point line, the wind speed and the fault type at least comprises 3 x 2 = 12 working conditions;

the wind speed is that the strong wind indicates the force of 0.9p.u. to 1.0p.u., and the wind speed is that the weak wind indicates the force of 0.1p.u. to 0.3p.u.

Compared with the prior art, the invention has the beneficial effects that:

aiming at the direct-drive wind turbine, the invention provides a method for identifying related control modes and control parameters by combining a least square method and a high/low voltage ride through control principle on the basis of PSASP simulation software, establishes a universal electromechanical transient model, can avoid the problem of large simulation result error caused by the software adopting default parameters, and provides a model basis and a universal and efficient identification method for safe and stable operation of a power grid.

The invention provides a high-voltage ride through parameter identification method for carrying out quick and fine electromechanical transient modeling on a direct-drive wind turbine in actual engineering, and in fact provides a quick and fine electromechanical transient modeling method for a direct-drive wind turbine aiming at the actual engineering.

Drawings

FIG. 1 is a structure diagram of an electromechanical transient model of a type 2 direct-drive wind turbine.

Fig. 2 is a voltage ride through operating state switching and current limiting control diagram.

FIG. 3 is a flowchart of the high voltage ride through parameter identification.

Fig. 4 is a diagram of a high voltage fault generating device.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which it is apparent that only a part of the embodiments of the present invention are described. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

The invention aims to solve the problems that the existing direct-driven wind turbine generator electromechanical transient model modeling method cannot be well suitable for actual engineering, the established wind turbine generator transient model is poor in universality and the parameter identification implementation process is complex, and further provides a direct-driven wind turbine generator transient model high-voltage ride through parameter identification method. The invention mainly focuses on the high voltage ride through process of the direct-drive permanent magnet wind turbine, and the high voltage ride through simulation response data obtained through simulation of a high voltage ride through test model is made to approximate to the actually measured response data of the direct-drive wind turbine by identifying the related parameters of the high voltage ride through control, so that the control parameters (the control parameters are also parameters to be identified) under the optimal high voltage ride through control strategy are determined.

The wind machine of the direct-drive permanent magnet wind turbine (permanent magnet synchronous generator, PMSG) is directly connected with a permanent magnet synchronous generator, a gear box is omitted, and a stator winding is connected with a full-power converter and then is integrated into a power grid. Based on the basic structure and principle of the direct-drive permanent magnet wind turbine, a series of direct-drive wind turbine transient models are established in PSASP software, wherein parameter identification is mainly carried out on the 2-type direct-drive wind turbine transient model, and the 2-type direct-drive wind turbine transient model provided in FIG. 1 comprises the conventional wind energy-power conversion model, the pitch angle control model, the transmission shaft model, the torque control model, the generator/converter model and other sub-models, and the voltage crossing control model (directly marked in FIG. 1) added on the basis is used for realizing high and high voltage crossing of the wind turbine. The transient model of the 2-type direct-driven wind turbine generator is an existing model in PSASP software.

The model related to high voltage ride through control in the transient model of the 2-type direct-drive wind turbine mainly comprises a generator/converter model and a high voltage ride through control sub-model in the voltage ride through control model (the invention does not relate to the low voltage ride through control sub-model in the voltage ride through control model, and therefore the invention does not describe the same). The parameters of other sub-models do not influence the high voltage ride through process of the wind turbine, and parameters or default parameters provided by a wind turbine instruction book can be directly adopted so as to ensure the normal operation of a transient model of the wind turbine.

The generator/converter model comprises:

(a) A generator model, the model parameters comprising: rated power, rated rotational speed, rotational inertia;

(b) The high voltage crossing state judging model includes: entering high voltage ride-through threshold VH _in Exit from high voltage ride through threshold VH _out ；

(c) A current transformer model, the model parameters comprising: maximum and minimum values of active power, reactive power and apparent power, and maximum and minimum values of active current, reactive current and total current.

And (II) the high voltage ride through control submodel comprises:

(a1) A current limit submodule: and setting current priority modes in a normal running state and a fault crossing state, so that the output of active or reactive current is preferentially ensured under the condition that the wind turbine generator is limited by the upper limit value of the current of the converter. The reactive priority and the active priority are calculated as follows:

wherein I is _pmax 、I _qmax 、I _max Respectively the maximum value of active current, reactive current and total current of the converter, I _pmin 、I _qmin 、I _min Respectively the minimum values of active current, reactive current and total current of the converter, I _{p_cmd} 、I _{q_cmd} The active current command value and the reactive current command value are respectively; in order to fully provide reactive power support for the wind turbine generator during high voltage ride through, reactive power priority control is adopted during the high voltage ride through, active output is preferentially ensured under a normal running state, and active priority control is selected.

(b1) An operation state switching sub-module: the method is used for switching the running state of the fan;

the fan comprises four running states, namely a normal running state, a high voltage ride through recovery running state and a high voltage ride through failure running state. The power output of the fan is controlled by a converter in normal running state, the control strategy in high voltage ride through is started in running state in high voltage ride through, the fan is switched off in failure state in high voltage ride through, and the control strategy in high voltage ride through recovery is started in recovery running state in high voltage ride through.

The active and reactive current control output of the converter in the normal running state is I _pcmd ′、I _qcmd ' active and reactive current control output of the converter in the high voltage ride through operation state is I _{pcmd_HVRT} 、I _{qcmd_HVRT} The method comprises the steps of carrying out a first treatment on the surface of the As shown in fig. 2, the converter finally outputs an active and reactive current command I _{p_cmd} 、I _{q_cmd} Is determined by the operating state, the high voltage ride through control strategy and the current limiting model.

(c1) An operating state control sub-module in high voltage ride through:

the operation state control submodule in the high-voltage ride through comprises 3 control modes including active current control, reactive current control and current control in an asymmetric high-voltage ride through operation state, and when in actual operation, one of the specific controls included in the 3 control modes is needed to be selected, so that the wind turbine generator control in the operation state in the high-voltage ride through is realized together. The reason for leading the wind turbine generator to enter the high-voltage crossing state mainly comprises two conditions of symmetrical faults and asymmetrical faults of fault points, the three-phase voltage rise belongs to symmetrical faults, and the single-phase or two-phase voltage rise belongs to asymmetrical faults. The control modes (1) and (2) are needed under the condition of the symmetrical fault points, and the control mode (3) is needed under the condition of the asymmetrical fault points.

The control strategy of the operation state control submodule in the high voltage ride through comprises the following steps:

(1) The active current control mode of the wind turbine generator comprises the following steps: (1) the active current has no additional control, (2) the active power control is appointed, (3) the active current control is appointed, and (4) the active current control before the push-through is carried out;

(2) Reactive current control mode of wind turbine generator system: (1) reactive current no additional control, (2) designating reactive power control, (3) designating reactive current control;

(3) Current control mode during asymmetric high voltage ride through: (1) control in a symmetric fault handling manner, (2) control based on positive sequence voltage, (3) control based on negative sequence voltage, (4) correction control based on symmetric fault current and negative sequence voltage.

(d1) The control strategy of the high voltage ride through recovery running state control sub-module comprises the following steps:

(1) Active current control mode of crossing the recovery starting point: (1) active power across recovery onset no additional control, (2) control by initial active current percentage, (3) control by active current during failure, (4) control by active power during failure;

(2) And (3) a reactive current control mode of traversing a recovery starting point: (1) the method comprises the steps of (1) carrying out reactive power no additional control through a recovery starting point, (2) controlling according to initial reactive current, (3) controlling according to reactive current percentage in a fault period, and (4) controlling according to reactive power percentage in the fault period;

(3) The active power recovery control mode of the wind turbine generator comprises the following steps: (1) active power recovery has no additional control, (2) active power recovery is controlled according to a slope, and (3) active power recovery is controlled according to an inertia curve;

(4) The reactive power recovery control mode of the wind turbine generator comprises the following steps: (1) reactive power recovery has no additional control, (2) reactive power recovery is controlled according to an inertia curve.

The high voltage ride through recovery running state control submodule in the high voltage ride through control submodule and the control strategy in the high voltage ride through control submodule are all control strategies built in a transient model of the direct-driven wind turbine through PSASP software, and are the prior art.

Referring to fig. 3, the method for identifying the transient model high voltage ride through parameters of the direct-drive wind turbine generator according to the present embodiment includes the following steps:

s1, establishing a transient model of a direct-drive wind turbine by PSASP software, and carrying out parameter configuration on the transient model of the direct-drive wind turbine by utilizing basic parameters acquired by a wind turbine instruction book and response data actually measured in the whole process of high voltage ride through under all test working conditions;

the implementation mode for carrying out parameter configuration on the basic parameters and the actually measured response data under the high voltage crossing state under all the test working conditions by utilizing the wind turbine generator instruction book is as follows:

The basic parameters obtained from the wind turbine generator instruction book and the P obtained by calculation according to the actually measured response data in the high voltage crossing state under all the test working conditions _max 、Q _max 、S _max 、P _min 、Q _min 、S _min 、I _pmax 、I _qmax 、I _max 、I _pmin 、I _qmin And I _min Filling a transient model of the direct-drive wind turbine generator; wherein P is _max 、Q _max And S _max Maximum values of active power, reactive power and apparent power of the converter respectively, P _min 、Q _min And S is _min Respectively the minimum values of active power, reactive power and apparent power of the converter, I _pmax 、I _qmax And I _max Respectively the maximum value of active current, reactive current and total current of the converter, I _pmin 、I _qmin And I _min The minimum values of the active current, the reactive current and the total current of the converter are respectively obtained.

The basic parameters comprise the rated power of the generator, the rated rotating speed of the generator, the rotational inertia of the generator, the rated wind speed, the cut-in wind speed, the cut-out wind speed, the radius of the blade and the rated rotating speed of the wind turbine.

The whole high voltage ride through process comprises a normal running state, a middle running state of high voltage ride through, a recovery running state of high voltage ride through and a normal running state after failure; the high voltage ride through running state and the high voltage ride through recovery running state are collectively called as a high voltage ride through state; the actually measured response data comprise line voltage, active current, reactive current, active power and reactive power of a fault point;

S2, based on a high voltage ride-through test model established according to the high voltage fault trigger circuit, adjusting fault point line voltage U corresponding to each test working condition in the high voltage ride-through test model during high voltage ride-through _{Fault_HVRT} To make the fault point line voltage U under each test working condition _{Fault_HVRT} The voltage is consistent with the actually measured fault point line voltage under the test working condition, and the fault point positive sequence voltage U under the test working condition during the high voltage crossing period is calculated by utilizing a high voltage crossing test model _{1_HVRT} ；

in step S3, according to the positive sequence voltage U of the fault point under the test working condition corresponding to all the fault points which do not enter the high voltage crossing state _{1_HVRT} Identifying high voltage ride through state judgment parameter VH _in And VH _out In the process of (1), firstly, judging whether the running state of the wind turbine generator set under each test working condition enters the high voltage crossing state according to the actually measured reactive power of the fault point under each test working condition during the high voltage crossing period, and Positive sequence voltage U from fault point under test working condition corresponding to all non-high voltage crossing state _{1_HVRT} Find the positive sequence voltage maximum U _{1_HVRT_max} The method comprises the steps of carrying out a first treatment on the surface of the According to the positive sequence voltage maximum U _{1_HVRT_max} Determining high-voltage ride-through state judgment parameter VH of wind turbine generator _in And VH _out . When judging whether the running state of the wind turbine generator under each test working condition enters a high voltage crossing state, the reactive power output of the wind turbine generator is suddenly reduced by more than 0.1p.u., and the wind turbine generator can be judged to enter the high voltage crossing state if the wind turbine generator is considered to have a high voltage fault.

after parameter identification is carried out based on the high-voltage ride-through response data of the actual wind turbine, the obtained parameters are required to be input into a transient model of the 2-type direct-drive wind turbine, high-voltage ride-through simulation test is carried out, and the accuracy of the parameter identification result and the simulation model is verified. The transient model test and simulation of the wind turbine generator are based on the following steps:

GB/T19963.1-2021 wind farm access power system technology specifies part 1-land wind power;

the verification rule of the electrical simulation model of the NB/T31053-2021 wind turbine generator;

NB/T31075-2016 wind farm electrical simulation model modeling and verification protocol.

The obtained control parameters are input into a high-voltage ride-through test model, so that the wind turbine generator performs simulation test on all test conditions under each ride-through combined control strategy, and simulation response data corresponding to all test conditions under the current ride-through combined control strategy is obtained; the response data comprises active current, reactive current, active power and reactive power;

the independent control strategy in the high-voltage ride through running state control submodule in the high-voltage ride through control submodule in the transient model of the direct-drive wind turbine generator system under the running state in the high-voltage ride through comprises the following steps:

(2) active power control is specified:

P _HVRT ＝K _P-HVRT *P ₀ +P _{set_HV} (3)

K _{P_HVRT} and P _{set_HV} All are used as control parameters (i.e. parameters to be identified);

(3) active current control is specified:

Ip _HVRT ＝K _1-Ip-HV *V _t +K _2-Ip-HV *Ip ₀ +Ip _{set_HV} (4)

K _{1_Ip_LV} 、K _{2_Ip_LV} and Ip _{set_LV} All are used as control parameters (i.e. parameters to be identified);

wherein Ip is ₀ The active current of the wind turbine generator set in a normal running state; ip (internet protocol) _HVRT The active current of the wind turbine generator set in the running state in the high voltage ride through is obtained; v (V) _t Positive sequence voltage value of the fan outlet; k (K) _1-Ip-HV Calculating a coefficient for active current No. 1; k (K) _2-Ip-HV Calculating a coefficient for active current No. 2; ip (internet protocol) _{set_HV} Setting the active current as an active current;

(2) designating reactive power control:

Q _HVRT ＝K _{Q_HVRT} *Q ₀ +Q _{set_HV} (5)

K _{Q_HVRT} and Q _{set_HV} All are used as control parameters (i.e. parameters to be identified);

(3) Designating reactive current control;

Iq _HVRT ＝K _{1_Iq_HV} *(VH _in -V _t )+K _{2_Iq_HV} *Iq ₀ +Iq _set-HV (6)

K _{1_Iq_HV} 、K _{2_Iq_HV} 、Iq _set-HV and VH _in All are used as control parameters (i.e. parameters to be identified);

(3) An asymmetric high voltage ride through current control scheme comprising:

(2) based on positive sequence voltage control:

K _1-Ip-HV-UBL 、K _2-Iq-HV-UBL 、Ip _{set_HV-UBL} 、K _1-Iq-HV-UBL 、K _{2-Iq_HV_UBL} and Iq _{set_HV_UBL} All are used as control parameters (i.e. parameters to be identified);

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _{1_Ip_HV_UBL} Calculating coefficient K for active current of No. 1 asymmetric fault _{2_Ip_HV_UBL} Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV-UBL} For the set value of the active current of the asymmetrical fault, K _{1_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _{2-Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 2; iq _{set_HV_UBL} Set value of reactive current for asymmetrical fault, V _t Is the positive sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

(3) negative sequence voltage control:

K _{1_Ip_HV_UBL} 、K _2-Iq-HV-UBL 、Ip _{set_HV-UBL} 、K _1-Iq-HV-UBL 、K _2-Iq-HV-UBL and Iq _set-HV-UBL All are used as control parameters (i.e. parameters to be identified);

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _1-Ip-HV-UBL Calculating coefficient K for active current of No. 1 asymmetric fault _{2_Ip_HV_UBL} Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV_UBL} For the set value of the active current of the asymmetrical fault, K _{1-Iq_HV-UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _2-Iq-HV-UBL Calculating a coefficient for the asymmetric fault reactive current of No. 2; iq _{set_HV_UBL} Set value of reactive current for asymmetrical fault, V _2t Is the negative sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

K _{3_Ip_HV_UBL} 、K _{3_Iq_HV_UBL} as control parameters (i.e., parameters to be identified);

wherein K is _{3_Ip_HV_UBL} Calculating coefficient K for active current of No. 3 asymmetric fault _{3_Iq_HV_UBL} Coefficients are calculated for the asymmetric fault reactive current No. 3.

And when parameter fitting is carried out on the combined control strategy in each crossing of the operation state control sub-module in the high voltage crossing of the high voltage crossing control sub-model in the transient model of the direct-driven wind turbine generator, a curve fitting technology of a least square method is adopted to realize the parameter fitting. The least square method fits a curve according to the principle of least sum of squares of deviation. Taking the reactive power control parameter of the wind turbine generator identified by adopting the designated reactive power control as an example, firstly, according to the actual measurement response curve of the reactive power of the wind turbine generator, collecting the reactive power of the wind turbine generator at the steady-state moment before and at the steady-state moment during the fault under all test working conditions, and respectively marking as Q ₀ And Q _HVRT Will Q ₀ And Q _HVRT Performing least square fitting according to formula (5), and identifying control parameter K in the control mode _{Q_HVRT} And Q _{set_HV} 。

Similarly, in order to verify the accuracy of the parameter identification result and the simulation model, each combination control strategy in the crossing process is respectively combined with various combination control strategies in the recovery process to form a plurality of groups of high-voltage crossing control strategies; inputting the obtained control parameters into a high voltage ride through test model, and enabling the wind turbine generator to perform simulation test on all test conditions under each group of high voltage ride through control strategies to obtain simulation response data corresponding to all test conditions under the current high voltage ride through control strategies;

the independent control strategy in the high voltage ride through recovery running state control submodule in the high voltage ride through control submodule in the transient model of the direct-drive wind turbine generator under the high voltage ride through recovery running state comprises the following steps:

the high voltage ride-through recovery running state control submodule comprises 4 control modes including ride-through recovery starting point active current control, active power recovery control and reactive power recovery control, and when in actual operation, one of specific controls contained in the 4 control modes is used as a combination control strategy in recovery, so that the wind turbine control of the high voltage ride-through recovery running state is realized together.

1b, controlling according to the initial active current percentage:

wherein Ip is _HVRSP Active current for crossing the recovery onset;the initial active current percentage coefficient (parameter to be identified); />To recover the starting active current set value (parameter to be identified);

2c, controlling according to the reactive current percentage during the fault:

wherein Iq _HVRSP Reactive current for traversing the recovery origin; To recover the starting reactive current set value (parameter to be identified); />The reactive current percentage coefficient (parameter to be identified) during the fault;

2d, controlling according to the reactive power percentage during the fault:

wherein Q is _HVRTSP Reactive power for traversing the recovery origin;to recover the starting reactive power set value (parameter to be identified); />The reactive power percentage coefficient (parameter to be identified) during the fault;

(3) Active power recovery control:

3b, active power recovery is controlled according to the slope:

P _HVRECO ＝min(P _HVRTRSP +K _{P_RECO} ·t,P ₀ ) (13)

wherein P is _HVRECO Active power during high voltage ride through recovery; p (P) _HVRTRSP Active power for recovering the starting point; k (K) _{P_RECO} Is the active power recovery slope (parameter to be identified); t is the high voltage ride through recovery time; p (P) ₀ The active power of the wind turbine generator set in a normal running state;

3c, active power recovery is controlled according to an inertia curve:

wherein T is _{P_RECO} Recovering an inertia constant (parameter to be identified) for the active power;

(4) Reactive power recovery control:

4b, reactive power recovery is controlled according to an inertia curve:

Wherein Q is _HVRECO Reactive power during high voltage ride through recovery; q (Q) _LVRTRSP To recover the starting reactive power; t (T) _{Q_RECO} The inertia constant (parameter to be identified) is recovered for the reactive power.

S6, calculating response errors between the high voltage ride through whole process simulation response data corresponding to all working conditions under each group of high voltage ride through control strategies and the actual measurement response data of the high voltage ride through whole process under the corresponding working conditions respectively to obtain a group of response errors; and selecting the component with the largest number of working conditions meeting the response error requirement and the smallest average response error from all the group response errors corresponding to the high-voltage ride-through control strategies of all the groups, and taking the control parameter corresponding to the component as the control parameter for controlling the transient model of the direct-drive wind turbine, thereby completing parameter identification. Wherein, each group of response errors comprises the response errors between actual measurement and simulation under each working condition.

More specifically, the basic parameters of the actual wind turbine generator set to be subjected to parameter identification are obtained through specifications of the wind turbine generator set with the corresponding model, and response data actually measured in the high voltage crossing state under all the test working conditions in the high voltage crossing detection report are obtained. The measured response data in the high voltage ride through detection report should at least include line voltage, reactive current, active power and reactive power of the fault point. The test working conditions at least comprise working conditions that the voltage of a fault line is increased to 120%, 125% and 130%, the wind speed is high wind (output 0.9p.u. to 1.0 p.u.) and low wind (output 0.1p.u. to 0.3 p.u.), the fault types are three-phase faults and two-phase faults, and the total is at least 3.2.2=12.

Examples:

(a) Filling basic parameters (rated power, rated rotation speed, rotational inertia, rated wind speed, cut-in wind speed, cut-out wind speed, blade radius and rated rotation speed of a wind turbine) obtained from a wind turbine generator instruction book into a transient model of the wind turbine generator, calculating the maximum value of active current, reactive current, total current, active power, reactive power and apparent power of a converter and the minimum value corresponding to the maximum value based on the current and the maximum value of power of all working conditions in actual measurement data, and filling into the transient model of the wind turbine generator;

(b) As shown in FIG. 4, FIG. 4 is a schematic diagram of a high voltage fault trigger circuit required by the transient model of the wind turbine in the relevant test and simulation standards, and a current limiting impedance Z is required to be connected between the high voltage side of the step-up transformer of the wind turbine and an external power grid _sr And a bypass switch CB1 connected in parallel with the current limiting impedance, and a boost branch is connected between the current limiting impedance and the wind turbine generator set boost transformer. The boost branch is concretely formed by closing a short circuit switch CB3 and a boost branch capacitor C _L And a step-up resistor R _d And the two parts are connected in series. In addition, the data measurement point is positioned at the high-voltage side (namely, the fault point) of the step-up transformer of the wind turbine generator. Based on the high-voltage fault triggering circuit structure, a high-voltage crossing test model is established, a wind turbine generator is connected into a power grid through a step-up transformer and two sections of current collecting circuits in sequence, a fault point (namely a step-down branch access point) is positioned between the two sections of current collecting circuits, the function of a step-up branch is simulated through a PSASP transient fault setting function, the high-voltage crossing test model is obtained, and the subsequent parameter identification and simulation verification processes are based on the test model; identifying a high-voltage fault access impedance value, adjusting the line voltage during the high-voltage crossing period to be consistent with the actual measurement data under each working condition, and calculating to obtain the positive sequence voltage during the fault period;

(c) Judging the running state of the wind turbine generator under each voltage rise working condition according to the actually measured data of reactive power under each working condition, and estimating a high voltage crossing state judgment parameter VH of the wind turbine generator _in And VH _out The method comprises the steps of carrying out a first treatment on the surface of the When the reactive power output of the wind turbine generator is suddenly reduced by more than 0.1p.u. after the high voltage fault occurs, the wind turbine generator can be judged to enter a high voltage crossing state, and the positive sequence voltage maximum value in the fault crossing period in the working condition without entering the high voltage crossing state is U _{1_HVRT_max} Then there is VH _in ＝VH _out ＝U _{1_HVRT_max} +0.03p.u.；

(d) The actual measurement data of the wind turbine generator in the running state in the high voltage ride through is combined with the running state control submodule in the high voltage ride through to obtain control parameters in different control mode combinations by fitting, and the specific flow is as follows: specific control combinations of all possible running state control sub-modules in the high voltage ride through are enumerated, for all the control combinations, the curve fitting technology based on the least square method is utilized to obtain control parameters of each control combination through fitting (parameter fitting is not needed for parameter-free control, only the control is needed), the obtained control parameters are filled into a transient model of the wind turbine, and further wind turbine line voltage, reactive current, active power and reactive power response data in the running state in the high voltage ride through under each working condition are obtained through simulation test;

(e) The actual measurement data of the wind turbine generator in the high voltage ride through recovery running state is utilized, and the control sub-modules in the high voltage recovery state are combined to obtain the control parameters in different control mode combinations by fitting, wherein the specific flow is as follows: specific control combinations of all possible high-voltage ride-through recovery running state control submodules are enumerated, for all the control combinations, a curve fitting technology based on a least square method is utilized to obtain control parameters of each control combination in a fitting mode (parameter fitting is not needed for parameter-free control, only the control is needed), the obtained control parameters are filled into a transient model of the wind turbine, and further line voltage, reactive current, active power and reactive power response data of fault points under the high-voltage ride-through recovery running state of each working condition are obtained through simulation test;

(f) And calculating response errors of the transient model of the direct-drive wind turbine generator, which is obtained based on the parameter identification method, and measured data before, during and after the faults of each working condition by using the simulation test data of each working condition obtained by the steps, and selecting a control mode combination with the maximum number of working conditions meeting the upper limit requirement of the response errors and the minimum average response error and parameters thereof as parameter identification results. The parameter identification result comprises the following parameters: the parameters of the generator, the parameters of the converter, the parameters in (1) - (3) contained in the high voltage ride through running state control sub-module and the parameters in (1) - (4) contained in the high voltage ride through recovery running state control sub-module.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in ways other than as described in the original claims. It is also to be understood that features described in connection with separate embodiments may be used in other described embodiments.

Claims

1. The method for identifying the transient model high-voltage ride through parameters of the direct-drive wind turbine generator is characterized by comprising the following steps of:

2. The method for identifying the high-voltage ride through parameters of the transient model of the direct-drive wind turbine generator according to claim 1, wherein the basic parameters comprise rated power of the generator, rated rotation speed, moment of inertia, rated wind speed, cut-in wind speed, cut-out wind speed, blade radius and rated rotation speed of the wind turbine.

3. The method for identifying the transient model high-voltage ride through parameters of the direct-drive wind turbine generator according to claim 2, wherein the response data comprises line voltage, active current, reactive current, active power and reactive power of the fault point.

4. The method for identifying the transient model high voltage ride through parameters of the direct drive wind turbine generator according to any one of claims 1 to 3, wherein the high voltage ride through test model is as follows:

5. The method for identifying parameters of high voltage ride through of a transient model of a direct drive wind turbine generator according to claim 4, wherein the individual control strategy in the high voltage ride through operational state control submodule in the transient model of the direct drive wind turbine generator in the operational state of the high voltage ride through in step S4 comprises:

(2) active power control is specified:

P _HVRT ＝K _{P_HVRT} *P ₀ +P _{set_HV} (3)

K _{P_HVRT} and P _{set_HV} All are used as control parameters;

(3) active current control is specified:

Ip _HVRT ＝K _{1_Ip_HV} *V _t +K _{2_Ip_HV} *Ip ₀ +Ip _{set_HV} (4)

wherein Ip is ₀ The active current of the wind turbine generator set in a normal running state; ip (internet protocol) _HVRT The active current of the wind turbine generator set in the running state in the high voltage ride through is obtained; v (V) _t Positive sequence voltage value of the fan outlet; k (K) _{1_Ip_HV} Calculating a coefficient for active current No. 1; k (K) _{2_Ip_HV} Calculating a coefficient for active current No. 2; ip (internet protocol) _{set_HV} Setting the active current as an active current;

(2) designating reactive power control:

Q _HVRT ＝K _{Q_HVRT} *Q ₀ +Q _{set_HV} (5)

K _{Q_HVRT} and Q _{set_HV} All are used as control parameters;

(3) designating reactive current control;

wherein Iq ₀ Reactive current of the wind turbine generator set in a normal running state; iq _HVRT Reactive current of the wind turbine generator set in the running state in high voltage ride through; v (V) _t Is positive sequence voltage value of fan outlet, K _{1_Iq_LV} Calculating a coefficient for reactive current No. 1; k (K) _{2_Iq_LV} Calculating a coefficient for reactive current No. 2; iq _{set_HV} Setting a reactive current value; VH (VH) _in To enter a high voltage ride through threshold;

(3) An asymmetric high voltage ride through current control scheme comprising:

(2) Based on positive sequence voltage control:

K _{1_Ip_HV_UBL} 、K _{2_Iq_HV_UBL} 、Ip _{set_HV_UBL} 、K _{1_Iq_HV_UBL} 、K _{2_Iq_HV_UBL} and Iq _{set_HV_UBL} All are used as control parameters;

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _{1_Ip_HV_UBL} Calculating coefficient K for active current of No. 1 asymmetric fault _{2_Ip_HV_UBL} Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV_UBL} For the set value of the active current of the asymmetrical fault, K _{1_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _{2_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 2; iq _{set_HV_UBL} Set value of reactive current for asymmetrical fault, V _t Is the positive sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

(3) negative sequence voltage control:

wherein Ip is _{HVRT_UBL} Active current of the wind turbine generator set during asymmetrical high-voltage ride through; iq _{HVRT_UBL} Reactive current of the wind turbine generator during asymmetrical high voltage ride through; k (K) _{1_Ip_HV_UBL} Calculating coefficient K for active current of No. 1 asymmetric fault _{2_Ip_HV_UBL} Active current calculation coefficient, ip of No. 2 asymmetric fault _{set_HV_UBL} For the set value of the active current of the asymmetrical fault, K _{1_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 1; k (K) _{2_Iq_HV_UBL} Calculating a coefficient for the asymmetric fault reactive current of No. 2; iqse _{t_HV_UBL} Set value of reactive current for asymmetrical fault, V _2t Is the negative sequence voltage value of the outlet of the fan, VH _in To enter a high voltage ride through threshold;

K _{3_Ip_HV_UBL} 、K _{3_Iq_HV_UBL} as a control parameter;

6. The method for identifying high voltage ride through parameters of a transient model of a direct drive wind turbine generator according to claim 5, wherein the individual control strategy in the high voltage ride through control sub-module in the transient model of the direct drive wind turbine generator in the high voltage ride through recovery operation state in step S5 comprises:

1b, controlling according to the initial active current percentage:

wherein Ip is _HVRSP Active current for crossing the recovery onset;is an initial active current percentage coefficient; />To recover the starting active current set point;

2c, controlling according to the reactive current percentage during the fault:

wherein Iq _HVRSP Reactive current for traversing the recovery origin;the reactive current set value is recovered to the starting point; / >The reactive current percentage coefficient is used during faults;

2d, controlling according to the reactive power percentage during the fault:

wherein Q is _HVRTSP Reactive power for traversing the recovery origin;to recover the starting reactive power set point; />As a percentage of reactive power during a faultCoefficients;

(3) Active power recovery control:

3b, active power recovery is controlled according to the slope:

P _HVRECO ＝min(P _HVRTRSP +K _{P_RECO} ·t,P ₀ ) (13)

3c, active power recovery is controlled according to an inertia curve:

wherein T is _{P_RECO} Recovering an inertia constant for the active power;

(4) Reactive power recovery control:

4b, reactive power recovery is controlled according to an inertia curve:

7. The method for identifying high voltage ride through parameters of a transient model of a direct drive wind turbine generator according to claim 6, wherein the step S3 is characterized in that the high voltage ride through state determination in the state of not entering the high voltage ride through state is based on the following:

8. The method for identifying high voltage ride through parameters of transient model of direct drive wind turbine generator according to claim 7, wherein the high voltage ride through state determination parameter VH in step S3 _in ＝VH _out ＝U _{1_HVRT_max} +0.03p.u.。

9. The method for identifying the high-voltage ride through parameters of the transient model of the direct-driven wind turbine generator system according to claim 8 is characterized in that a least square method is adopted for curve fitting when parameter fitting is carried out in the steps S4 and S5.

10. The method for identifying high voltage ride through parameters of a transient model of a direct drive wind turbine generator according to claim 9, wherein all conditions in S6 are determined by a combination of fault point voltage rise, wind speed and fault type, wherein the fault point voltage rise is at least 120%, 125% and 130%, the wind speed is at least high wind and low wind, the fault type is at least three-phase fault and two-phase fault, the fault point voltage rise, the wind speed and fault type combination comprises at least 3 x 2 = 12 conditions;