WO2014005550A1

WO2014005550A1 - Simulation verification method for low voltage ride-through capability of wind farm

Info

Publication number: WO2014005550A1
Application number: PCT/CN2013/078903
Authority: WO
Inventors: 迟永宁; 王真; 李琰; 李庆; 魏林君; 张梅; 汤海雁
Original assignee: 国家电网公司; 中国电力科学研究院; 中电普瑞张北风电研究检测有限公司
Priority date: 2012-07-05
Filing date: 2013-07-05
Publication date: 2014-01-09
Also published as: CN102799722B; CN102799722A

Abstract

Provided is a simulation verification method for the low voltage ride-through capability of a wind farm. The method comprises the steps of: according to a verified wind turbine generator set electrical simulation model, analyzing the operation characteristics of the wind turbine generator set; establishing a wind farm electrical simulation model, and verifying whether a wind farm has a low voltage ride-through capability; and establishing a regional power system simulation model which comprises the wind farm electrical stimulation model, and checking the impact of wind farm grid connection on the safe and stable operation of a power system. Provided is a complete valid method for verifying the low voltage ride-through capability of a wind farm, which has a positive significance in judging whether the wind farm satisfies the grid connection requirements, avoiding large-scale wind power off-grid accidents and ensuring the safe and stable operation of a power grid, and lays a foundation for the establishment and improvement of a wind power grid connection authentication system in China.

Description

Simulation verification method for low voltage ride through capability of wind farm

The invention belongs to the field of power system simulation and verification, and particularly relates to a simulation verification method for low voltage ride through capability of a wind farm. Background technique

In recent years, under the favorable policy and technological progress, China's wind power has developed rapidly, and its operation technology, dispatch management, and standard system have reached the world's advanced level. At present, the wind power of power grids in several provinces and regions in the “Three North” region has leapt to the second largest installed power source in the regional power grid. The safe operation of wind power has become an important factor to ensure the safe operation of large power grids. During the strong winds in 2011, the safety problems of wind power operation in some provinces were concentrated, and large-scale wind turbine off-site accidents occurred in the “Three North” area, which had a serious impact on the safe and stable operation of the power grid. The loss of a de-networking accident with the greatest impact on the safe and stable operation of the power grid reached 1.54 million kilowatts. The grid frequency was reduced to 49.765 Hz at the lowest, and the limit was 5 seconds. The 330kV bus voltage was reduced to 230.6kV, which was 69.88% of the rated voltage. After many accident investigations and analysis, it is found that there are safety hazards such as the active/reactive power of the wind turbine, the low/high voltage ride-through capability, the lack of dynamic reactive power support capability, and the failure of the reactive power equipment to meet the standard. In several accidents in 2011, wind turbines accounted for 58% of low-voltage off-grid, and high-voltage off-grid accounted for 27%.

To this end, the relevant national regulations and national standards GB/T 19963-2011 "Wind Farm Access to Power System Technical Regulations" require wind turbines / wind farms to have low voltage ride through capability, and wind turbines should pass the test of qualified institutions, The wind farm should be verified by low voltage ride through capability to operate on the grid. The large-scale centralized access system for wind power is a special problem encountered in the development of wind power in China. There is no international experience to draw on. Therefore, based on the facts of wind power development in China, based on the ability to test the low voltage traversing field of wind turbines, research and invention are aimed at The simulation verification method for low voltage ride through capability of wind farms is necessary and unnecessary. Summary of the invention

In order to overcome the above deficiencies of the prior art, the present invention provides a simulation verification method for low voltage ride through capability of a wind farm, which is positive for determining whether a wind farm meets grid connection requirements, avoiding large-scale wind power off-network accidents, and ensuring safe and stable operation of the power grid. The significance has laid the foundation for the establishment and improvement of China's wind power grid integration system.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for verifying a low voltage ride through capability of a wind farm, the method comprising the following steps: Step 1: Analyze the operating characteristics of the wind turbine;

Step 2: Establish an electric simulation model of the wind farm to verify whether the wind farm has low voltage ride through capability;

Step 3: Establish a regional power system simulation model including the wind farm electrical simulation model, and verify the impact of the wind farm integration on the safe and stable operation of the power system.

The step 1 includes the following steps:

Step 1-1: collecting electrical parameters of the wind turbine;

Step 1-2: Analyze the operating characteristics of the wind turbine based on the verified wind turbine electrical simulation model.

The wind turbine electrical parameters include basic information of the wind turbine, generator parameters, converter parameters, main control system parameters, and other electrical parameters.

The basic information of the wind turbine includes a wind turbine model, a rated power, a rated apparent power, a rated current, a rated voltage, a hub height, and a rated wind speed; the generator parameters include a generator model, a rated power, a rated apparent power, Voltage, frequency and open-circuit voltage of the rotor; the converter parameters include grid-side converter rated power, motor-side converter rated power, grid-side converter rated apparent power, motor-side converter rated apparent power , DC side chopper type, DC side chopper model, DC side chopper resistance, DC side chopper resistance, DC side chopper resistance capacity, Crowbar type, Crowbar model, Crowbar resistance, Crowbar resistance and Crowbar capacity; The parameters include the type and control characteristics of the control system; the other electrical parameters include overvoltage protection settings, low voltage protection settings, high frequency protection settings, and low frequency protection settings.

The step 2 includes the following steps:

Step 2-1: collecting the electrical equipment parameters, electrical topology information, the equivalent impedance and short circuit capacity of the wind power grid, and the relay protection parameters in the wind farm;

Step 2-2: Establish an electric simulation model of the wind farm;

Step 2-3: Analyze the operating characteristics of the wind farm, and verify whether the wind farm has low voltage ride through capability through fault simulation.

The production electrical equipment parameters include box transformer parameters, feeder system parameters, main transformer parameters, reactive compensation equipment parameters, and wind farm transmission line parameters.

The box transformer parameters include a model of a box transformer, a capacity, a voltage tap, a wiring group, an impedance voltage, a short circuit loss, a no-load loss, and a no-load current; the feeder system parameters include the length and type of each feeder. , rated current, positive sequence / negative sequence / zero sequence resistance, reactance and capacitance to ground; the main transformer parameters include the main transformer type, capacity, voltage tap, wiring group, impedance voltage, short circuit loss, no load Loss and no-load current; the reactive power compensation equipment parameters include the type of wind farm reactive power compensation equipment, inductive/capacitive installation capacity and actual available capacity, system response time and protection The wind farm sending line parameters include the line length, model, rated current, positive sequence/negative sequence/zero sequence resistance, reactance and capacitance to ground of the wind farm sending line.

The relay protection parameters include the over/undervoltage protection setting of the wind turbine/wind farm, the over/under frequency protection setting and the short circuit protection setting of the wind farm grid/wind turbine.

The step 3 includes the following steps:

Step 3: 1: Establish a regional power system simulation model including the wind farm electrical simulation model;

Step 3-2: Analyze the transient stability of the wind farm and the grid operation, and verify the low voltage ride-through capability of the wind farm; Step 3-3: Analyze the impact of the wind farm integration on the safe and stable operation of the power system.

Compared with the prior art, the beneficial effects of the invention are:

1. GB/T 19963-2011 “Technical Regulations for Wind Farm Access to Power Systems” clearly defines the low voltage ride-through capability of wind farms and has corresponding data indicators. The invention provides a complete and effective method for verifying the low voltage ride through capability of a wind farm, and has positive significance for determining whether the wind farm meets the grid connection requirements, avoiding large-scale wind power off-network accidents and ensuring safe and stable operation of the power grid;

2. The method provided by the invention has important practical value, and can comprehensively evaluate the low voltage crossing capability of the wind farm, and lays a foundation for the establishment and improvement of the wind power grid integration system in China;

3. The method is simple, reliable, easy to implement and widely used. DRAWINGS

1 is a flow chart of a simulation verification method for a low voltage ride through capability of a wind farm in an embodiment of the present invention;

Figure 2 is a schematic diagram of the national standard GB/T 19963-2011 wind farm low voltage ride through requirements;

Figure 3 is a schematic diagram of the low voltage protection setting of the wind turbine to be verified;

Figure 4 is a schematic diagram of a wind turbine operating characteristic verification simulation system;

Figure 5 is a schematic diagram of the transient characteristics of the unit when the fan terminal voltage drops to zero;

Figure 6 is a schematic diagram of the transient characteristics of the unit when the fan terminal voltage drops below 0.7 pu;

Figure 7 is a schematic diagram of the transient characteristics of the unit when the fan terminal voltage drops to 0.7 pu;

Figure 8 is a wiring diagram of the wind farm to be verified;

Figure 9 is a schematic diagram of the voltage level in the field when the voltage at the grid point of the wind farm drops to zero;

Figure 10 is a schematic diagram of the active/reactive output of the fan when the voltage at the grid point of the wind farm drops to zero;

Figure 11 is a schematic diagram showing the different voltage drop levels of the wind farm's grid-connected points and the corresponding fan terminal voltage;

Figure 12 is a schematic diagram of the active/reactive output of the fan under different voltage drops at the grid-connecting point of the wind farm; Figure 13 is a schematic diagram of the wind farm voltage in which the phase-side short-circuit fault occurs on the grid side line and the main protection action; Figure 14 is a schematic diagram of the active/reactive power output of the fan in the phase-failure of the grid-side line and the main protection action; Figure 15 shows the grid-side line occurrence Schematic diagram of wind farm voltage with phase short circuit fault and backup protection action;

Figure 16 is a schematic diagram of the active/reactive output of the fan with phase short-circuit fault and backup protection action on the grid side line.

The invention will be further described in detail below with reference to the accompanying drawings.

Figure 1, a simulation method for low voltage ride through capability of a wind farm, the method comprising the following steps:

Step 1: According to the verified wind turbine electrical simulation model, analyze the operating characteristics of the wind turbine; Step 2: Establish a wind farm electrical simulation model to verify whether the wind farm has low voltage ride through capability;

Wind farms use different wind turbines and different control systems, and their grid-connected operation will have different impacts on the grid. On the basis of fully understanding the steady-state and dynamic characteristics of the wind turbines used, combined with the grid structure characteristics of the local power grid, the impact of the grid-connected operation of the wind farm on the grid and the corresponding technical measures are studied to ensure the wind farm investment. Safe and stable operation after transportation plays an extremely important role.

Figure 2 shows the requirements of the national standard GB/T 19963-2011 “Technical Regulations for Wind Farm Access to Power Systems” for low voltage surge penetration capability of wind farms. When the voltage at the grid connection point of the wind farm drops to 20% of the nominal voltage, the wind turbine in the wind farm can guarantee continuous operation for 625 ms without off-grid; the voltage at the grid point of the wind farm can recover to 90% of the nominal voltage within 2 s after falling. Wind turbines in wind farms can guarantee continuous operation without off-grid. For three-phase, two-phase short-circuit faults, the assessment voltage is the line voltage of the wind farm connected to the grid; for the single-phase ground short-circuit fault, the assessment voltage is the phase-to-point phase voltage. For a wind farm that has not been cut during a power system failure, its active power should be quickly recovered after the fault is cleared. From the time of fault clearing, the power change rate of at least 10% of rated power/second is restored to the value before the fault.

The following is a preferred embodiment of the invention.

1. Analyze the operating characteristics of the wind turbine based on the verified wind turbine electrical simulation model.

Based on the verified wind turbine electrical simulation model and wind turbine technical data, the grid-connected operation characteristics of the wind turbine are studied and confirmed.

(1) Main parameters of wind turbines and box transformers;

Main parameters of a certain type of fan: rated power 2MW, generator power factor is 1.0, protection class IP54, stator (line) voltage 690V, frequency 50Hz, pole number 4, rotor rated speed 16.7 rev/min, speed range 9-19 Rev/min, The wind speed is cut into 4m/s, the wind speed is cut off at 25m/s, and the rated wind speed is 15m/s.

(2) Wind turbine low voltage protection setting;

The low voltage protection setting of the wind turbine is shown in Figure 3. When the curve is out of range, the wind turbine will be disconnected from the grid.

(3) Unit characteristics simulation system;

In order to facilitate the analysis and description of the dynamic characteristics of wind turbines under typical faults, a simple network is selected as the simulation system, as shown in Figure 4. The wind turbine is connected to the infinite grid via a box transformer, collector circuit and step-up transformer. The high voltage side of the box is 35kV, the high voltage side of the step-up transformer is 220kV, and the infinite power supply voltage is set to 1.0pu.

(4) Simulation of wind turbine operating characteristics:

(a) The fan terminal voltage drops to 0 when the fault occurs;

When the fault causes the fan terminal voltage to drop to 0, the transient characteristics of the unit operation are shown in Figure 5. The three-phase short-circuit fault occurred in the system, causing the terminal voltage of the wind turbine to drop from l.Opu to 0. In the fault, the unit's active/reactive output is zero. Since the wind turbine has low voltage ride-through capability, if the three-phase short-circuit fault is cleared at 0.2s, the wind turbine can keep running in the grid during and after the fault, and the turbine active/reactive output returns to a stable value after a short oscillation. , the terminal voltage returns to a stable level before the fault. However, if the three-phase short-circuit fault exceeds 0.2s, the voltage exceeds the low-voltage protection setting and the fan is disconnected.

(b) When the fault occurs, the fan terminal voltage drops below 0.7 pu;

When the fan terminal voltage drops below 0.7 pu in the event of a fault, the transient characteristics of the unit operation are shown in Fig. 6. The three-phase short circuit of the system causes the terminal voltage of the wind turbine to drop from 0.60u to 0.69pu (by adjusting the grounding resistance of the fault point). In the fault, the active power generated by the wind turbine is rapidly reduced. If the three-phase short-circuit fault is cleared at 2.65s, the wind turbine will remain connected to the grid during the fault and after the fault. The active/reactive output of the unit will return to the stable value after a short oscillation, and the voltage of the terminal will return to the stable level before the fault. . However, if the three-phase short-circuit fault clearing time exceeds 2.65s, the voltage exceeds the low-voltage protection setting value, and the fan is disconnected.

(c) The fan terminal voltage drops to 0.7 pu at the time of failure;

When the terminal voltage of the wind turbine falls to 0.7 pu during the fault, the transient characteristics of the unit operation are shown in Fig. 7. The three-phase short-circuit fault of the system causes the terminal voltage of the wind turbine to drop from l.Opu to 0.7 pu (by adjusting the grounding resistance of the fault point). During the fault, the active power generated by the unit is rapidly reduced. If the fault is cleared in lis, the wind turbine can remain connected to the grid during and after the fault. The active/reactive output returns to a stable value after a brief oscillation, and the terminal voltage returns to the stable level before the fault. However, if the three-phase short-circuit fault clearing time exceeds lis, the voltage exceeds the low-voltage protection setting value, and the fan is disconnected.

2. Establish an electric simulation model of the wind farm to verify whether the wind farm has low voltage ride through capability;

According to the wind farm electrical equipment technical data, the wind farm simulation model is built in the simulation program DIgSILENT/PowerFactory, and the simulation of the wind farm low power output (0.1 P _n P 0.3 P _n ) and full power output (1.0P _n ) under, Various short-circuit faults occurred in the power grid, and the voltage of the grid point dropped to 90% U _n , 75% U _n , 50% 1^ and 20% U _n , respectively, and the low voltage ride-through capability of the wind farm was realized, and the wind farm energy was evaluated. Whether to achieve the low voltage ride-through capability required by the national standard GB/T 19963-2011 "Technical Regulations for Wind Farm Access to Power Systems".

(1) Wind farm model

Figure 8 shows the wind farm simulation model. The total installed capacity of the wind farm is 249.3MW, and 58 850kW fans and 100 2MW fans are installed. The wind turbine terminal voltage in the wind farm is 690V, and is boosted to 35/33kV by the unit wiring method of "one machine, one change (box type change)", and then connected to the wind farm 220kV after being collected by the 35/33kV field collector line. Boost station. A total of 3 main transformers are installed in the booster station. The three collector circuits of IA, IB and IC are connected to 58 850kW fans and connected to the #1 main transformer. The four collector circuits of IID, IIE, IIF and IIG are combined with 50 2MW fans. Access #2 main transformer, ΠΙΗ, 1111, III J, IIIK four collector circuits are connected to 50 2MW fans and then connected to #3 main transformer. The wind farm is connected to the system through a 220kV transmission line with a line length of 19km and a wire type of LGJ-300/40.

(2) Simulation verification of low voltage ride through capability of wind farm

(a) Simulation analysis of short-circuit faults causing the voltage at the grid point of the wind farm to fall to zero

A three-phase short-circuit fault occurs at the grid connection point of the wind farm, and the fault is cleared by 0.19s. Figure 9 and Figure 10 show the variation curve of the wind farm voltage at the time of failure and the active/reactive output curve of some wind turbines in the field. The voltage at the grid connection point of the wind farm drops to 0. The voltage at the terminal of the wind turbine is rapidly falling, but both are above 0.15 pu. After the short-circuit fault is cleared, the voltage at the grid point of the wind farm and the voltage at the fan end are quickly restored.

The wind farm is in a full state before the short circuit fault occurs, and the reactive power output of the wind turbine is zero. After the short-circuit fault occurs, the active output drops to near zero output; due to the control strategy of the unit itself, the faulty wind turbine can emit reactive power. After the fault, the active output of the wind turbine starts to recover, and can recover to the level before the fault within 3s, and the reactive output quickly returns to zero.

When the voltage of the wind farm's grid-connected point falls to zero due to the fault, all wind turbines in the field can not only keep the grid running for at least 0.2s, but also can generate reactive power during the fault, support the voltage recovery of the wind farm and the grid, and the wind power after the fault. The active output of the unit can be restored to the pre-fault level within 3 seconds.

(b) Simulation analysis of short-circuit faults leading to other drop levels of wind farm grid-connected voltage

According to the requirements of the low voltage traversing of the wind farm in Figure 2, when the system failure causes the wind farm grid point voltage to drop to 0.20 pu, 0.50 pu, 0.75 pu and 0.90 pu, all wind turbines in the wind farm should be kept at least connected to the grid. 0.625s, 1.21s, 1.71s and 2.0s. When the voltage of the grid connection point drops to 0.20 pu, 0.50 pu, 0.75 pu and 0.90 pu respectively during the fault (by adjusting the grounding resistance of the fault point to achieve different drop depths of the grid point voltage), Figure 11 shows the voltage at the grid point of the wind farm. And the curve of the voltage of the terminal of some wind turbines. When the three-phase short-circuit fault occurs at the grid-connected point of the wind farm, the voltage of the grid-connected point drops to 0.2 pu, the voltage of the wind turbine unit is above 0.35 pu, and the wind turbine can keep the grid running for at least 0.63 s during the fault; when the short-circuit fault causes the grid voltage When falling to 0.5 pu, the wind turbine terminal voltage will be above 0.62 pu, and all wind turbines can remain at least 1.22 s during the fault; when the short-circuit fault causes the wind farm grid point voltage to drop to 0.75 pu, the wind turbine terminal voltage will be Above 0.8 pu, the wind turbine can maintain grid-connected operation for at least 1.71 s during the fault; when the fault causes the grid-connected point voltage to drop to 0.9 pu, the wind turbine terminal voltage will be above 0.9 pu, and the grid-connected operation can be maintained for at least 2 s.

Figure 12 shows the active/reactive power curve of #101 fan (2MW) under different types of short-circuit faults. When the short-circuit fault occurs, the greater the voltage drop at the grid-connected point, the greater the drop in the unit's active output. The longer it takes for the active power to return to the pre-fault level after the fault is cleared. When the voltage at the grid connection point of the wind farm drops to 0.2 pu, the active output of the #101 unit will drop from 2 MW to 0.32 MW, and the time required to return to the full level after the fault is cleared is about 1.5 s; and when the grid point voltage drops to 0.9. When pu, the active output of the #101 wind turbine is reduced from 2MW to 1.76MW, and the time required to return to full level after the fault is cleared does not exceed 0.5s.

In the normal operation mode, the reactive power output of the #101 wind turbine is zero, and the wind turbine will emit a certain reactive power after the short-circuit fault occurs. When the grid-connected point voltage drops to 0.2 pu during the fault, the reactive power generated by the wind turbine during the fault is about 0.77 Mvar; when the grid-connected point voltage drops to 0.5 pu, the reactive power that the wind turbine can emit is 1.03 Mvar; When the voltage at the grid point drops to 0.9 pu, the reactive power generated by the wind turbine is very small, about 0.07 Mvar.

The fault simulation analysis of the two-phase grounding short-circuit fault and the single-phase short-circuit fault at the grid point when the wind farm is full and the wind farm is at low output is omitted.

The results show that under various fault modes, the wind turbines maintain the grid-connected operation time, and the wind farm can achieve low voltage ride through during the fault.

3. Establish a regional power system simulation model including the wind farm electrical simulation model to verify the impact of wind farm integration on the safe and stable operation of the power system.

In combination with the actual access system of the wind farm and the operation of other wind farms in the regional power grid, when the simulated wind farm is full, when the short-circuit fault occurs on the grid side, it can verify whether the wind farm can achieve low voltage ride through and stable operation; If there is a problem with the stability of the power system containing the wind farm, corresponding measures and recommendations are proposed.

(1) Three-phase short circuit fault occurs on the line

(a) Line main protection action

A three-phase short-circuit fault occurs in a line near the wind farm, the main protection action of the 0.12s line, and the fault line is cut off. The transient process of the voltage in the wind farm and the active/reactive output of the unit is shown in Figure 13 and Figure 14.

When a three-phase short-circuit fault occurs on a line, the voltage at the grid connection point of the wind farm will drop to 0.22 pu, the wind farm booster station The 35kV bus and the 33kV bus voltage are between 0.30 and 0.50 pu. The voltage and active output of each wind turbine in the wind farm fell sharply, and the terminal voltage dropped to between 0.30 and 0.60 pu, and the active output was close to zero. After the fault occurs, the wind turbine is switched from active/reactive power control in normal operation to rotor current control, so that the wind turbine can generate reactive power. During the fault period, the reactive power of the 850kW wind turbine is between 0.30~0.50Mvar, 2MW. The reactive power generated by the wind turbine is between 0.8 and 1.0 Mvar.

The 0.12s main protection action cuts off the faulty line, and the wind farm booster station voltage and the unit's terminal voltage are quickly restored. After the fault, the active output of the wind turbine can be restored to the pre-fault level within 2.5s. The active recovery capability meets the standard "The active power should be restored to the value before the fault with a power change rate of at least 10% of rated power/second". Claim. After the fault is cleared, the wind turbine is switched from rotor current control to active/reactive power control, and the reactive output is reduced to zero.

After the fault, the grid and wind farm voltages will quickly return to a stable level; the system frequency and the normal unit speed will return to a stable value after a brief oscillation.

(b) Line backup protection action

After the line fault, the 0.12s main protection fails to operate correctly, and the 0.62s backup protection action cuts the fault line. In the event of a line short-circuit fault, the drop level and duration of the wind turbine's terminal voltage are within the allowable range of the unit's low-voltage protection. The low-voltage protection of the wind turbine does not operate during the fault. When the duration of the short-circuit fault reaches 0.62 s, the unit that is causing the nearby thermal power plant will oscillate greatly, resulting in a large fluctuation of the frequency of the nearby power grid. The amplitude and duration of the frequency exceed the set value of the high-frequency protection of the wind turbine (51 Hz, 0.2s), the unit is disconnected due to high-frequency protection action; when a three-phase short-circuit fault occurs, the bus voltage of the wind farm booster station, the wind turbine generator terminal voltage and the active output are greatly reduced, and the wind turbine generates reactive power in the fault. , to provide reactive support for the system, as shown in Figure 15, Figure 16. After the backup protection action cuts the fault line, the voltage of the wind farm booster station recovers quickly.

When a three-phase short-circuit fault occurs on the line and the fault line is cut off by the backup protection action, the system can maintain transient stability, but the voltage of the wind farm's grid-connected point and the grid slightly fluctuates after the fault is cleared.

(2) Other fault simulation

The simulation of a two-phase short-circuit fault, a single-phase short-circuit fault, and a three-phase, two-phase, single-phase short-circuit fault on a critical line is omitted.

4. Wind farm low voltage ride through capability simulation verification conclusion.

(1) The wind farm meets the national standard GB/T 19963-2011 "Technical Regulations for Wind Farm Access to Power Systems" requirements for low voltage ride through capability.

(2) When the wind farm grid point voltage is below the voltage contour specified by the grid connection guide, the wind turbine can maintain grid-connected operation for at least 0.2s, and reactive power can be generated during the fault period to support the voltage recovery of the wind farm and the power grid. . (3) A short circuit fault occurs in some transmission lines or busbars near the wind farm access point, and the main protection fails to operate correctly. When the backup protection action is required to clear the fault, the wind farm may be caused by overfrequency protection or high voltage protection action. The whole wind turbine is partially or partially disconnected.

(4) The over-frequency and over-voltage continuous processes in the system fault and after the fault are usually short-lived. It is recommended that the wind farm and the fan manufacturer make appropriate limits for the frequency protection and over-voltage protection of the wind turbine under the premise of the performance of the unit. Changes, relaxing the requirements for frequency and overvoltage.

It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be The invention is to be construed as being limited to the scope of the appended claims.

Claims

Rights request

A simulation method for verifying a low voltage ride through capability of a wind farm, characterized in that: the method comprises the following steps:

Step 1: Analyze the operating characteristics of the wind turbine;

2. The method for verifying and verifying a low voltage ride through capability of a wind farm according to claim 1, wherein the step 1 comprises the following steps:

Step 1-1: collecting electrical parameters of the wind turbine;

3. The method for verifying and verifying a low voltage ride through capability of a wind farm according to claim 2, wherein: the electrical parameters of the wind turbine include basic information of the wind turbine, generator parameters, converter parameters, main control system parameters, and others. Electrical parameters.

4. The method for verifying and verifying a low voltage ride through capability of a wind farm according to claim 3, wherein: the basic information of the wind turbine comprises a wind turbine model, a rated power, a rated apparent power, a rated current, a rated voltage, and a hub height. And rated wind speed; the generator parameters include generator model, rated power, rated apparent power, voltage, frequency, and open circuit voltage of the rotor; the converter parameters include grid-side converter rated power, motor-side converter current Rated power, grid-side converter rated apparent power, motor-side converter rated apparent power, DC side chopper type, DC side chopper model, DC side chopper resistance, DC side chopper resistance, DC side chopper resistance Capacity, Crowbar type, Crowbar model, Crowbar resistance, Crowbar resistance and Crowbar capacity; the main control system parameters include the type and control characteristics of the control system; the other electrical parameters include overvoltage protection settings, low voltage protection settings, High frequency protection settings and low frequency protection settings.

The method for verifying the low voltage ride through capability of a wind farm according to claim 1, wherein the step 2 includes the following steps:

Step 2-2: Establish an electric simulation model of the wind farm;

6. The method for verifying low voltage ride through capability of a wind farm according to claim 5, wherein: the parameters of the production type electrical equipment include box type transformer parameters, feeder line system parameters, main transformer parameters, reactive power compensation equipment parameters, and The wind farm sends out the line parameters.

7. The method for verifying and verifying a low voltage ride through capability of a wind farm according to claim 6, wherein: the box transformer parameters include a model, a capacity, a voltage tap, a wiring group, an impedance voltage, and a short circuit of the box type transformer. Loss, no-load loss and no-load current; the feeder system parameters include the length, type, rated current, positive sequence/negative sequence/zero sequence resistance, reactance and capacitance to ground of each feeder; the main transformer parameters include Main transformer type, capacity, voltage tap, wiring group, impedance voltage, short circuit loss, no-load loss and no-load current; The reactive power compensation equipment parameters include the type of wind farm reactive power compensation equipment, inductive/capacitive Installation capacity and actual available capacity, system response time and protection setting; said wind farm transmission line parameters include line length, model, rated current, positive sequence/negative sequence/zero sequence resistance, reactance and grounding of the wind farm transmission line Capacitance value.

8. The method for verifying low voltage ride through capability of a wind farm according to claim 5, wherein: the relay protection parameter comprises an over/under voltage protection setting of the wind turbine/wind farm, and an over/under frequency protection setting. Short-circuit protection setting with the wind farm's grid point/wind turbine.

The method for verifying the low voltage ride through capability of a wind farm according to claim 1, wherein the step 3 includes the following steps: