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André Mermoud

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  1. I have reconstituted your configuration. The problem is that when defining the inverter list, you have the following warnings in orange: Sub-array #1, NInv no match Sub-array #3, NInv no match This should produce an error, which doesn't appear when you do the design in this window, but appears when reopening the variant: The fact that this message doesn't appear when designing the system is indeed an mistake, but the specified configuration is well stored on the file. You should simply press the button "Adjust subarrays" and everythis will be OK.
  2. The data specified on the datasheets of these 2 battery blocks RESU7H and RESU10H are indeed incoherent. These correspond probably to 2 or 3 modules type RESU 3.3, i.e. 2x or 2x 51.8V with 63 Ah, with a DC-DC bidirectional converter for a 400 V external voltage. . This is not implemented as such in PVsyst. As a workaround, I have defined these devices as batteries of 108 cells in series (400V) , with reduced capacity (17 or 25 Ah). These will be available in the next version 7.4.5 of PVsyst.
  3. Please have alook on your first dialog (top of your first post). You have defined a battery pack of 512V / 103 Ah, i.e. 52.7 kW "gross". You have defined a PV system which will deliver 5.4 kW under full irradiance, corresponding to a full charging in roughly 7.8 hours). This is quite correct. For this Power limit you could even define a smaller battery pack, corresponding to one day of overload (see "clear day excess energy" on the next page). Now on the page "Peak shaving", you have to define the "Battery input charger" power which will charge the battery. Here you have probably defined a device of 50 kW, which is highly oversized. You could define a charger of, say, 6 kW, and everythig will be OK. Same remark for the "Battery to grid" inverter power: this power will determine the speed at which you will discharge the battery during night.
  4. The number of cells is defined on the page "Size and technology". In your case, the Vmpp = 39.27 V at STC, indeed corresponding to 66 cells, i.e. a voltage of 0.595 V/cell, which is quite correct. Now when you are using the model under different irradiance and temperature, the Voc is obviously different (here higher than at STC as the temperature is lower then 25°C).
  5. Yes indeed, we are aware of this problem. For the version 7.4.3, we have implemented the new complex rules specified by Huawei, for the implementation and use of their optimizers. For doing this, Huawei provided 2 very different protocols, for low power (450 and 600W) and high power(1100 – 1300 W) optimizers. The protocol for high powers specifies that you can only connect one string per MPPT. What we did and is on the basis of our new implementation. We thought that this statement was also valid for the low power optimizers, and we developed this complex tool with this hypothesis. But it appears that this is not the case. The only way of using your 450 W with several strings per MPPT is to revert to the previous version 7.4.2. However the versions 7.4.2 is not compatible with the patchs 7.4.3 (or 7.4.4, 7.4.5): you cannot use them in parallel, you will have to uninstall the V 7.4.3. If you really need to keep parallel versions, you can install the version 7.3.4, which may be installed/used in parallel with the versions 7.4.3. This will be corrected in a version 7.4.6, to be released in January 2024.
  6. In PVsyst, all the AC losses expressed as percentages are referenced to a same power. This power may be either the STC power of the PV array, or the PNom output limit of the inverters. You can modify this choice in the Project's settings (button at top of the project's dialog). You can have a look on the help "Project design > Array and system losses > AC ohmic losses: reference power".
  7. Please carefully read the report: - on the left you have the transformer characteristics, with a nominal power of 5.3 MVA. - on the right you have the operating conditions, showing the "Nominal power at STC. This is the reference power for the wiring loss estimations in percentage.
  8. No, the LID loss only arises with P-type wafers.
  9. First: the fact that the battery pack is provided by a manufacturer doesn't mean that this is correct. The definition of batteries in PVsyst is complex, and I have seen several BTR files from manufacturers which were erroneous. I am working on this Grid systems simulation with storage just now, and I have discovered errors is some specific cases, namely when the battery has several "blocks" in parallel, and with disproportioned loads or battery packs. You should wait for the next version 7.4.5 (to be released in December 2023) for a complete revision of this simulation in any case. NB: The fact that the EBatDis = 505.48 kW when the discharging limit = 500 kW is normal, as the 500 kW is the output of the inverter, when the EBatDis is the input. You have to account for the inverter efficiency.
  10. Sorry, we don't know any problem of this kind. Please check that in your first simulation, you have the same degradation parameters than for the Aging tool. If so, please send your full project to support@pvsyst.com, with a detailed explanation of your problem.
  11. The degraded PV module is calculated once. Then the simulation is performed with this module, for the simulation of the full year.. The effect on the yearly degradation loss is the average over the year, i.e. between the beginning and the end of the year. This is the reason of the half-values for the degradation factor.
  12. This configuration is different than the previous one. Here you have defined a charging power of 100 kW, ensuring a charge in 1.6 hours under full sun. This is more reasonable. This is close to what is acceptable for Li-Ion batteries. This charging time was 10 minutes at sun in the previous case, and as PVsyst works in houly steps, this leads to some problems when simulating one full hour. Normally PVsyst should not allow a charging/discharging Power - or current - exceeding the battery data. I don't know why this did not show the correct error message. Is your battery from the database, of from an external file ? I am just on the way of correcting these extreme problems for a next version. By the way, I persist to say that implementing a battery storage for storing an energy corresponding to 8 minutes of average consumption doesn't make sense. It depends on what you want to do with your system. If it is for an UPS (i.e. ensuring the continuity of the energy supply for a little securized part of your installation), you should define the discharging power consequently.
  13. As we should always keep a balance between the available energy and the demand, a stand-alone systems cannot work without a storage system. At each instant, the load will be satisfied by the PV production, and the battery if this is not sufficient. A possible genset is here especially for ensuring the needs when the battery is empty. Now the case where a constant power is permanently available from a genset has indeed not been foreseen in this strategy. If you really don't have a battery storage, you should consider this case as a "grid connected" system with self-consumption. The excess power generated by the PV array will be considered as a grid injection, and the energy from the Genset the energy "from grid" required by your load.
  14. If you want to become familiar with this topic, you should define realistic conditions. Otherwise you cannot understand the problem.
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