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ve.bus:grid-codes-and-loss-of-mains-detection

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ve.bus:grid-codes-and-loss-of-mains-detection [2020-07-21 14:52] – [2.5 How to identify if LOM detection causes issues?] mvaderve.bus:grid-codes-and-loss-of-mains-detection [2022-10-31 23:41] (current) – [2.8 Grid codes and Type A and Type B LOM] mvader
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 ==== 2.1 What is LOM detection? ==== ==== 2.1 What is LOM detection? ====
  
-LOM is an automatic process that detects a change and so loss of the mains/network/grid supply. After the detection, the inverter/charger will open its back-feed relay, making sure there is no live AC voltage on its AC-inputs, and anything connected to these inputs.+LOM is an automatic process that detects a loss of the mains/network/grid supply. After the detection, the inverter/charger will open its back-feed relay, making sure there is no live AC voltage on its AC-inputs, and anything connected to these inputs.
  
 ==== 2.2 Why is LOM detection required? ==== ==== 2.2 Why is LOM detection required? ====
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 To detect a loss of mains, the inverter/charger will constantly try to shift the AC frequency. When connected to a stable grid, with a normal accepted impedance, it will not be possible to do so, and it can therefore detect that the mains is still present. In case the mains was lost, the inverter/charger will be able to shift the frequency at will, without any resulting correction currents. To detect a loss of mains, the inverter/charger will constantly try to shift the AC frequency. When connected to a stable grid, with a normal accepted impedance, it will not be possible to do so, and it can therefore detect that the mains is still present. In case the mains was lost, the inverter/charger will be able to shift the frequency at will, without any resulting correction currents.
  
-When connected to a generator, or to a grid with a long extension cable or long ‘last mile’ cable, the pushing and pulling on the grid does create high currents, and as a result the inverter/charger algorithm can become unstable and switch itself off in overload.+When connected to a generator, or to a grid with a long extension cable or long ‘last mile’ cable, the impedance of the grid becomes much higher and the pushing and pulling on the grid will have a certain affect on the grid voltage. As a result the inverter/charger algorithm can become unstable, which, in rare cases, can result in high currents and the unit switching itself off in overload.
  
 ==== 2.4 How does LOM detection relate to passthru? ==== ==== 2.4 How does LOM detection relate to passthru? ====
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 This (can) cause a safety mechanism to activate which temporarily disables feed-in. This (can) cause a safety mechanism to activate which temporarily disables feed-in.
  
-==== 2.5 How to identify if LOM detection causes issues? ====+==== 2.5 How to identify if LOM detection causes overload issues? ====
  
-By temporarily disabling the LOM, one can identify that the LOM is causing an issue. Here is how to disable it:+By temporarily disabling the LOM, one can identify that the LOM is causing overload issues. Here is how to disable it:
  
 Open VEConfigure, and then on the Grid tab, change LOM detection setting to None. This requires a password, contact your dealer. Open VEConfigure, and then on the Grid tab, change LOM detection setting to None. This requires a password, contact your dealer.
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 Save the settings, and wait to see if this helps. Save the settings, and wait to see if this helps.
  
-In case disabling LOM solves the issue, one solution is to make for a better (lower impedance) connection to the utility. In case that can't be improved, another solution is to keep LOM disabled and install an external anti-islanding safety devices (ENS). For example from Ziehl, or another brand. They have different techniques of detecting a loss of mains, and can (often) therefor work without any problem. Detailed instructions for permanently disabling the built-in LOM feature are in the next chapter.+In case disabling LOM solves the overload issue, one solution is to make for a better (lower impedance) connection to the utility. In case that can't be improved, another solution is to keep LOM disabled and install an external anti-islanding safety devices (ENS). For example from Ziehl, or another brand. They have different techniques of detecting a loss of mains, and can (often) therefor work without any problem. Detailed instructions for permanently disabling the built-in LOM feature are in the next chapter.
  
-NOTE: for LOM to cause issues is really rare. Its documented in detail on this page to help installations where it does cause an issue, but its really rather rare to happen in the first place. Do make sure to read the [[ess:design-installation-manual|ESS manual, and especially its FAQ chapter]], for other common causes of issues when troubleshooting.+NOTE: for LOM to cause overload issues is really rare. Its documented in detail on this page to help installations where it does cause an issue, but its really rather rare to happen in the first place. Do make sure to read the [[ess:design-installation-manual|ESS manual, and especially its FAQ chapter]], for other common causes of issues when troubleshooting.
  
 ==== 2.6 Disabling LOM ==== ==== 2.6 Disabling LOM ====
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 To disable LOM, use VEConfigure and go to the Grid tab. A password is required to choose "Disabled" in the LOM options. Contact your dealer for the password. To disable LOM, use VEConfigure and go to the Grid tab. A password is required to choose "Disabled" in the LOM options. Contact your dealer for the password.
 +
 +KNOWN LIMITATION: Note that, even with the LOM detection disabled on an AC input, the inverter/charger will still use the acceptance limits required by the selected gridcode and thus in most cases be somewhat less acceptive on that input compared to setting the grid code to either code "None", "Other" and "Germany: VDE-AT-N 4105:2018-11 external NS protection".
  
 === Safety notes - Generator === === Safety notes - Generator ===
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 **Type A** is the strongest form of LOM detection resulting in the quickest detection time. It requires a low impedance connection to the grid (short, well sized cables). LOM Type A will not work with generators. **Type A** is the strongest form of LOM detection resulting in the quickest detection time. It requires a low impedance connection to the grid (short, well sized cables). LOM Type A will not work with generators.
  
-**Type B** has a more soft approach and a slightly longer detection time. Type B has been type tested and approved for most Multi/gridcode combinations. //(The only combination not tested so-far is MultiPlus/Quattro i.c.w. UK grid code. However this combination is most likely valid. It has just not been type tested yet.)//\\+**Type B** has a more soft approach and a slightly longer detection time. Type B has been type tested and approved for most Multi/gridcode combinations.  
 + 
 +The default value in VEConfigure is the approved value. When Type B is approved, Type A will not be shown in VEConfigure as an option, because there is no reason to prefer Type A over Type B in that case. 
 + 
 +BE AWARE: Whether a Multi/Quattro is approved for a certain country CANNOT be concluded from the fact that VEConfigure shows the option. Check the safety certificates on our website to see the allowed models for your country. 
 On generators, and also with installations having a relatively high impedance mains connection, Type B will work better than Type A. On generators, and also with installations having a relatively high impedance mains connection, Type B will work better than Type A.
  
-For generators on which also Type B does not work, see Disabling LOM.+For generators on which also Type B does not work, see the Disabling LOM section above, as well as the there noted limitation.
  
 ==== 2.8 Grid codes and Type A and Type B LOM ==== ==== 2.8 Grid codes and Type A and Type B LOM ====
  
-Some Grid codes will use Type A and others will use Type B. The Type that has been tested and approved for compliancy is marked with __grid code compliant__. See below screenshot.+At the time of writing all Grid codes use Type B or "LOM disabled" (Denmark does not allow active LOM detection). 
 + 
 +The Type that has been tested and approved for compliancy is marked with __grid code compliant__. See below screenshot.
  
   * Grid codes using Type A: VEConfigure lets you override that to Type B and/or disabling LOM.   * Grid codes using Type A: VEConfigure lets you override that to Type B and/or disabling LOM.
   * Grid codes using Type B: VEConfigure lets the installer override it to disabling LOM only.   * Grid codes using Type B: VEConfigure lets the installer override it to disabling LOM only.
 +  * Grid codes using "disabled": VEConfigure lets the installer override it to Type B only.
  
 {{ :ve.bus:grid_code_compliant.png?direct |}} {{ :ve.bus:grid_code_compliant.png?direct |}}
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 Some, bigger or better quality generators, will be able to work with LOM **Type B**. For other less stable generators it will be required to disable LOM entirely. In that case make the installation such that it is still safe: no simple extensions cords, use enclosed wiring cabinets with warnings on the outside and/or an external ENS. Some, bigger or better quality generators, will be able to work with LOM **Type B**. For other less stable generators it will be required to disable LOM entirely. In that case make the installation such that it is still safe: no simple extensions cords, use enclosed wiring cabinets with warnings on the outside and/or an external ENS.
 +
 +Note that it is also possible for some generators that it is not accepted by the inverter/charger at all, unless very specific grid codes are chosen. See the section "Disabling LOM" above for details.
  
 More information about Victron Inverter/chargers combined with Generators is in the [[https://www.victronenergy.com/live/multiplus_faq|MultiPlus Generator FAQ]]. More information about Victron Inverter/chargers combined with Generators is in the [[https://www.victronenergy.com/live/multiplus_faq|MultiPlus Generator FAQ]].
 +
 ==== Q4: I use ESS, but have disabled feed-back, is a grid-code still required? ==== ==== Q4: I use ESS, but have disabled feed-back, is a grid-code still required? ====
  
ve.bus/grid-codes-and-loss-of-mains-detection.txt · Last modified: 2022-10-31 23:41 by mvader
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