Photovoltaic energy storage simulation system and method thereof

Abstract

The invention discloses a photovoltaic energy storage simulation system and method, and belongs to the technical field of photovoltaic simulation systems.The photovoltaic energy storage simulation system comprises a photovoltaic power station model, an outlet switch, a local load, a boost transformer and measuring instruments, the measuring instruments comprise a voltmeter and a power meter, the photovoltaic power station model is connected with the power meter through a cable, and the power meter is connected with a photovoltaic bus through a cable; the photovoltaic bus is connected with a local load through a cable; the method comprises the following steps: 1, setting photovoltaic model parameters; and 2, a photovoltaic model test curve is obtained. Under the fault condition, the simulation system can output the reactive component to provide voltage support for the power grid according to the preset reactive support parameters, the reactive injection amount is also immediately zeroed after the fault disappears, the phenomenon of overvoltage is avoided, and the reliability of the system is improved. And meanwhile, the active component is gradually recovered to the level before the fault according to a preset recovery slope, and the photovoltaic model is kept in network-hanging operation in the process, so that the low-voltage ride-through under the fault condition is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic simulation systems, and in particular to a photovoltaic energy storage simulation system and a method thereof. Background Art

[0002] DDRTS is a digital dynamic real-time simulator for power systems that is currently widely used in China. By building various new energy power generation system models in DDRTS and integrating them into the conventional power grid, a new power grid system that includes both traditional power generation methods and new energy is formed. Then, various types of faults are triggered inside the power grid model to study the impact of the new energy power generation system on the transient response of the entire power grid, which is of great positive significance for ensuring the reliable and safe operation of the power grid. Therefore, a photovoltaic energy storage simulation system and method are proposed to solve the above problems. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the prior art and to propose a photovoltaic energy storage simulation system and method.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The photovoltaic energy storage simulation system includes a photovoltaic power station model, an export switch, an on-site load, a boost transformer and a measuring instrument. The measuring instrument includes a voltmeter and a power meter. The photovoltaic power station model is connected to the power meter via a cable. The power meter is connected to a photovoltaic busbar via a cable. The photovoltaic busbar is connected to an on-site load via a cable. The photovoltaic busbar is connected to an external power supply via a power line. The power line is connected to a grid module. The power supply is provided with an export switch and a boost transformer in series.

[0006] Preferably, the photovoltaic power station model is the main part of the photovoltaic model, and the parameter setting of the photovoltaic model includes two parts: illumination parameters and component parameters.

[0007] Preferably, the outlet switch is used to control the opening and closing of the photovoltaic model.

[0008] Preferably, the power of the local load is set according to demand, and its power is set to a low power to improve the smoothness of the output waveform.

[0009] Preferably, the step-up transformer increases the voltage of the new energy outlet and then integrates it into the upper-level power grid.

[0010] The method for using the photovoltaic energy storage simulation system includes the following steps:

[0011] S1. Set the photovoltaic model parameters: To set the illumination parameters, double-click the photovoltaic model icon to enter the lower control diagram page. The photovoltaic parameter settings are located in the input link on the left side of the module. Double-click the corresponding module to get the illumination data setting window.

[0012] To set component parameters, double-click the "Dg" subdirectory under the project directory and run the "DgSetting.exe" configuration program.

[0013] S2. Photovoltaic model test curve: After setting the illumination parameters, run the maximum power tracking curve under the change of illumination intensity, then add a fault point at the photovoltaic outlet, and set a three-phase fault to occur in about 1s to obtain a simulation waveform. Finally, set the feeder switch to trip at a certain moment at the 10kV outgoing line switch, then the photovoltaic model and its adjacent loads will form an island system. By setting a series of fault conditions during the simulation, the photovoltaic model test curve can be obtained.

[0014] Preferably, the photovoltaic parameter setting method in S1 is completed by a univariate nonlinear function, X01-X08 on the left side is the simulation time in seconds, and Y01-Y08 on the right side is the illumination data in W / ㎡. Figure 4 The setting means that the light intensity changes from 1000 to 800 at 0.51s, and the unit is W / ㎡.

[0015] Preferably, the method for setting the photovoltaic model component parameters in S1 is to first select the name of the corresponding photovoltaic component in the "Component List" drop-down box in the upper left corner, then select "Photovoltaic" in the "Component Type" drop-down box, and select the added photovoltaic output circuit breaker name in the "Outlet Circuit Breaker" drop-down box. After setting, you only need to select the corresponding component next time, and other parameters will be automatically imported and displayed.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The simulation system in this solution only needs to set the corresponding photovoltaic components for the first time, and then only needs to select the corresponding components, and other parameters will be automatically imported and displayed, thereby significantly reducing the time for parameter setting operations and improving parameter setting efficiency;

[0018] 2. Under fault conditions, the simulation system can output reactive components to provide voltage support to the grid according to pre-set reactive support parameters. After the fault disappears, the reactive injection amount will immediately return to zero to avoid overvoltage. At the same time, the active component will gradually recover to the pre-fault level according to the pre-set recovery slope. During this process, the photovoltaic model remains connected to the grid and achieves low voltage ride-through under fault conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A photovoltaic model installation location diagram in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0020] Figure 2It is a schematic diagram of a photovoltaic model in the photovoltaic energy storage simulation system and method proposed in the present invention;

[0021] Figure 3 A block diagram of setting illumination data in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0022] Figure 4 A schematic diagram of a setting window for illumination data in the photovoltaic energy storage simulation system and method thereof proposed by the present invention;

[0023] Figure 5 This is a window diagram of photovoltaic model component parameter settings in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0024] Figure 6 A maximum power tracking curve diagram under changes in light intensity in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0025] Figure 7 A low voltage ride-through curve diagram under fault conditions in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0026] Figure 8 A curve diagram of the islanding phenomenon after the external power grid is disconnected in the photovoltaic energy storage simulation system and method proposed by the present invention;

[0027] Fig. 9 It is a schematic diagram of an energy storage model icon in the photovoltaic energy storage simulation system and method proposed in the present invention;

[0028] Fig.10 A window diagram showing the working condition settings of the energy storage model in the photovoltaic energy storage simulation system and method proposed in the present invention;

[0029] Fig.11 This is a flowchart of the photovoltaic energy storage simulation system and method proposed in the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Reference Figures 1 to 11The photovoltaic energy storage simulation system includes a photovoltaic power station model, an export switch, a local load, a boost transformer and measuring instruments. The measuring instruments include a voltmeter and a power meter. The photovoltaic power station model is connected to the power meter through a cable. The power meter is connected to a photovoltaic bus through a cable. The photovoltaic bus is connected to the local load through a cable. The photovoltaic bus is connected to an external power supply through a power line. The power line is connected to a grid module. The export switch and the boost transformer are arranged in series on the power supply.

[0032] It is worth noting that voltage meters, power meters and other measuring meters can be added as needed. Except for the photovoltaic power station model, the rest are traditional models.

[0033] Furthermore, the photovoltaic power station model is the main part of the photovoltaic model, and the parameter setting of the photovoltaic model includes two parts: illumination parameters and component parameters.

[0034] Furthermore, the outlet switch is used to control the opening and closing of the photovoltaic model.

[0035] Furthermore, the power of the local load is set according to demand, and its power is set to a small power to improve the smoothness of the output waveform.

[0036] Furthermore, the step-up transformer increases the export voltage of the renewable energy and then integrates it into the upper-level power grid.

[0037] The method for using the photovoltaic energy storage simulation system includes the following steps:

[0038] S1. Set the photovoltaic model parameters: To set the illumination parameters, double-click the photovoltaic model icon to enter the lower control diagram page. Figure 3 As shown in the figure, the photovoltaic parameter settings are located in the input link on the left side of the module. Double-click the corresponding module to get the setting window of the illumination data, as shown in the figure. Figure 4 As shown;

[0039] To set the component parameters, double-click the "Dg" subdirectory under the project directory and run the "DgSetting.exe" configuration program. Figure 5 As shown;

[0040] S2. Photovoltaic model test curve: After setting the illumination parameters, run the maximum power tracking curve under the change of illumination intensity, such as Figure 6 As shown, then add a fault point at the photovoltaic outlet and set a three-phase fault to occur in about 1s to obtain a simulation waveform, as shown in Figure 7 As shown in Figure 2, finally, if the feeder switch is tripped at a certain time at the 10kV outgoing line switch, the photovoltaic model and its adjacent loads will form an island system, such as Figure 8 As shown in Figure 1, the photovoltaic model test curve can be obtained by setting a series of fault conditions during the simulation process.

[0041] It should be noted that: Figure 6 It can be seen that when the light intensity changes from 1000 to 800 in 0.5 seconds, the corresponding photovoltaic system output power will also decrease synchronously (the waveforms from top to bottom are photovoltaic active and reactive power, photovoltaic three-phase voltage, and photovoltaic three-phase current).

[0042] It should be noted that: Figure 6 It can be seen that the photovoltaic output three-phase current contains a small proportion of harmonic components. At present, the internal setting of the program sets the THD of the characteristic harmonics between 2% and 5%, which can be further adjusted and modified according to needs (the waveforms from top to bottom are photovoltaic active and reactive power, photovoltaic three-phase voltage, and photovoltaic three-phase current).

[0043] It should be noted that: Figure 7 It can be seen that a three-phase short circuit fault occurs in the power grid about 1s later, the voltage decreases, and the active power also decreases accordingly. Under the control of the converter, the output current of the photovoltaic model does not change much, and according to the pre-set reactive support parameters, the reactive component can be output during the fault to provide voltage support for the power grid. After the fault disappears, the reactive injection amount is immediately returned to zero to avoid overvoltage. At the same time, the active component gradually recovers to the level before the fault according to the pre-set recovery slope. During this process, the photovoltaic model maintains grid-connected operation and realizes low voltage ride-through in the event of a fault (the waveforms from top to bottom are the active and reactive power of photovoltaics, photovoltaic three-phase voltage, and photovoltaic three-phase current).

[0044] It should be noted that: Figure 8 It can be seen that the external grid is disconnected at about 2s, and the remaining photovoltaic models and adjacent loads form an island system. Due to the lack of grid voltage support and the load exceeding the output capacity of the photovoltaic model, the photovoltaic output voltage (the second coordinate graph) and output frequency (the blue curve in the first coordinate graph) are significantly reduced, and the entire island system operates under non-public frequency conditions.

[0045] Furthermore, the setting method of photovoltaic parameters in S1 is completed through a univariate nonlinear function. X01~X08 on the left is the simulation time in seconds, and Y01~Y08 on the right is the illumination data in W / ㎡. Figure 4 The setting means that the light intensity changes from 1000 to 800 at 0.51s, and the unit is W / ㎡.

[0046] Furthermore, the method for setting the parameters of the photovoltaic model components in S1 is to first select the name of the corresponding photovoltaic component in the "Component List" drop-down box in the upper left corner, then select "Photovoltaic" in the "Component Type" drop-down box, and select the added photovoltaic output circuit breaker name in the "Outlet Circuit Breaker" drop-down box. After setting, you only need to select the corresponding component next time, and other parameters will be automatically imported and displayed.

[0047] Furthermore, the energy storage model is similar to photovoltaic in overall structure, the difference is that the energy storage model does not include the calculation part of photovoltaic panel related parameters, and the photovoltaic active power can only be greater than or equal to 0, while the energy storage can work at a negative value as needed, that is, the mode of absorbing and storing electrical energy.

[0048] The operating conditions of the energy storage model are similar to those of photovoltaics, such as Fig.10 As shown, the default operating condition setting of the energy storage model is to run according to a certain active power curve. In actual use, the nonlinear function can be replaced with more complex logic (such as a controller link that can reflect the peak shaving and valley filling characteristics) as needed. In addition, the model can output the real-time SOC value of the energy storage. The upper and lower limits of the SOC can be set in the model. If it is higher than the upper limit, the active power will stop being absorbed, and if it is lower than the lower limit, the active power will stop being emitted.

[0049] When the present invention is used, the illumination parameters are set by a univariate nonlinear function. X01-X08 on the left are simulation time in seconds, and Y01-Y08 on the right are illumination data in W / ㎡. Figure 4 The setting means that the light intensity changes from 1000 to 800 at 0.51s, and the unit is W / ㎡;

[0050] Then set the photovoltaic component parameters, select the name of the corresponding photovoltaic component in the "Component List" drop-down box on the upper left, then select "Photovoltaic" in the "Component Type" drop-down box, and select the added photovoltaic output circuit breaker name in the "Outlet Circuit Breaker" drop-down box. After setting, you only need to select the corresponding component next time, and other parameters will be automatically imported and displayed;

[0051] After setting the illumination parameters, run the program to obtain the maximum power tracking curve under varying illumination intensity, as shown in the figure below: Figure 6 As shown in the figure, after setting the photovoltaic element parameters, a fault point is added at the photovoltaic outlet, and a three-phase fault is set to occur in about 1s, and a simulation waveform is obtained, as shown in the figure. Figure 7 As shown in Figure 2, finally, if the feeder switch is tripped at a certain time at the 10kV outgoing line switch, the photovoltaic model and its adjacent loads will form an island system, such as Figure 8 As shown in Figure 1, the photovoltaic model test curve can be obtained by setting a series of fault conditions during the simulation process.

[0052] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. Photovoltaic energy storage simulation system, including photovoltaic power station model, export switch, local load, boost transformer and measuring instrument, characterized in that: The measuring instruments include a voltmeter and a power meter. The photovoltaic power station model is connected to the power meter via a cable, the power meter is connected to a photovoltaic bus via a cable, the photovoltaic bus is connected to a local load via a cable, the photovoltaic bus is connected to an external power supply via a power line, the power line is connected to a power grid module, and an export switch and a step-up transformer are arranged in series on the power supply.

2. The photovoltaic energy storage simulation system according to claim 1, characterized in that: The photovoltaic power station model is the main part of the photovoltaic model, and the parameter setting of the photovoltaic model includes two parts: illumination parameters and component parameters.

3. The photovoltaic energy storage simulation system according to claim 1, characterized in that: The outlet switch is used to control the opening and closing of the photovoltaic model.

4. The photovoltaic energy storage simulation system according to claim 1, characterized in that: The local load sets power according to demand, and its power is set to a low power to improve the smoothness of the output waveform.

5. The photovoltaic energy storage simulation system according to claim 1, characterized in that: The step-up transformer increases the voltage of the new energy export and then integrates it into the upper-level power grid.

6. The method for using the photovoltaic energy storage simulation system according to any one of claims 1 to 5, comprising the following steps: S1. Set the photovoltaic model parameters: To set the illumination parameters, double-click the photovoltaic model icon to enter the lower control diagram page. The photovoltaic parameter settings are located in the input link on the left side of the module. Double-click the corresponding module to get the illumination data setting window. To set component parameters, double-click the "Dg" subdirectory under the project directory and run the "DgSetting.exe" configuration program. S2. Photovoltaic model test curve: After setting the illumination parameters, run the maximum power tracking curve under the change of illumination intensity, then add a fault point at the photovoltaic outlet, and set a three-phase fault to occur in about 1s to obtain a simulation waveform. Finally, set the feeder switch to trip at a certain moment at the 10kV outgoing line switch, then the photovoltaic model and its adjacent loads will form an island system. By setting a series of fault conditions during the simulation, the photovoltaic model test curve can be obtained.

7. The method for using the photovoltaic energy storage simulation system according to claim 6, characterized in that: The setting method of the photovoltaic parameters in S1 is completed through a univariate nonlinear function. X01~X08 on the left are simulation times in seconds, and Y01~Y08 on the right are illumination data in W / ㎡. The setting in Figure 4 means that the illumination changes from 1000 to 800 at 0.51s, in W / ㎡.

8. The method for using the photovoltaic energy storage simulation system according to claim 6, characterized in that: The method for setting the photovoltaic model component parameters in S1 is to first select the name of the corresponding photovoltaic component in the "Component List" drop-down box in the upper left corner, then select "Photovoltaic" in the "Component Type" drop-down box, and select the added photovoltaic output circuit breaker name in the "Outlet Circuit Breaker" drop-down box. After setting, you only need to select the corresponding component next time, and other parameters will be automatically imported and displayed.

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