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ve.bus:grid-codes-and-loss-of-mains-detection [2020-07-20 17:01]
pba [LOM detection Type A and Type B]
ve.bus:grid-codes-and-loss-of-mains-detection [2020-07-21 14:52] (current)
mvader [2.5 How to identify if LOM detection causes issues?]
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 All countries have their own legislation and therewith their own requirements with regards to the speed of Loss of mains detection, under & over voltages, accepted ramp times, and so forth. To make an installation comply to local regulations, the correct grid-code needs to be selected. All countries have their own legislation and therewith their own requirements with regards to the speed of Loss of mains detection, under & over voltages, accepted ramp times, and so forth. To make an installation comply to local regulations, the correct grid-code needs to be selected.
  
-The exact requirements differ widely between the countries. For example the normal Multis, Quattros and MultiCompacts are certified for use in the UK. For other countries, Germany for example, only the MultiGrid is and can be certified to be used without having to add more external anti-islanding safety devices (ENS). And in yet other countries an external ENS is required and/or the inverter/charger must be configured with the right grid-code. Check the safety certificates on our website to see the allowed models for your country.+The exact requirements differ widely between the countries. For example the normal Multis, Quattros and MultiCompacts are certified for use in the UK. For other countries, Germany for example, only the MultiPlus-II is certified to be installed without requiring additional external anti-islanding safety devices (ENS). And in yet other countries an external ENS is required and/or the inverter/charger must be configured with the right grid-code. Check the safety certificates on our website to see the allowed models for your country.
  
 +In certain situations, the inverter/charger built-in Loss of Mains detection (LOM) causes issues. This document explains how to identify if that is the case, as well as how to resolve.
 +
 +Make sure to also read [[ess:design-installation-manual|the ESS manual]], and when trouble shooting Overload and/or Passthru issues, then especially its FAQ Chapter.
 ===== 2. Loss of mains detection (LOM) ===== ===== 2. Loss of mains detection (LOM) =====
  
-==== 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 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.
  
-==== Why is LOM detection required? ====+==== 2.2 Why is LOM detection required? ====
  
 The purpose of LOM is to detect that the Multi is no longer connected to the mains. Be that a generator or the grid. In such case, the Multi needs to open its back-feed relay. Not doing that would be unsafe. Imagine an electrician working on the street, and disconnecting a house. He then needs to be able to safely work on the wiring from the house. The purpose of LOM is to detect that the Multi is no longer connected to the mains. Be that a generator or the grid. In such case, the Multi needs to open its back-feed relay. Not doing that would be unsafe. Imagine an electrician working on the street, and disconnecting a house. He then needs to be able to safely work on the wiring from the house.
  
-==== How does LOM detection relate to overload shutdowns? ====+==== 2.3 How does LOM detection relate to overload shutdowns? ====
  
 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.
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 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 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.
  
-==== How does LOM detection relate to passthru? ====+==== 2.4 How does LOM detection relate to passthru? ====
  
 Similar to above section about overload, a too weak connection to the utility can cause continuous increases and decreases in frequency, not resulting in overload but still resulting in continuous shifts in frequency. Similar to above section about overload, a too weak connection to the utility can cause continuous increases and decreases in frequency, not resulting in overload but still resulting in continuous shifts in frequency.
  
 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.
-==== How to identify if LOM detection causes issues? ====+ 
 +==== 2.5 How to identify if LOM detection causes 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 an issue. Here is how to disable it:
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 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.
  
-Save the settings, and wait to see if this helps. In case it does helpsee next section.+Save the settings, and wait to see if this helps. 
 + 
 +In case disabling LOM solves the issueone 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 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.
-==== What to do when LOM detection causes issues? ==== 
  
-The previous section explains how to identify if LOM causes an issue. It can cause overload shutdowns, and it can also cause a system to frequently show "Passthru" as a state. Mostly related to a high impedance connection to the utility.+==== 2.6 Disabling LOM ====
  
-The solution is then to make for better connection to the utility - but as that is often quite hard to achieve, here is another solutionkeep LOM disabled and install an external anti-islanding safety devices (ENS). For example from Ziehl, or another brand. Make sure to comply to local rules & regulations - this is a real critical safety issue.+There are few situations in which LOM needs to be disabled:
  
 +  - For certain generators
 +  - In case LOM causes Overload, Passthru or other issues while connected to the utility (see above)
  
 +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.
  
-==== LOM detection Type A and Type B ====+=== Safety notes - Generator ===
  
-Within the Victron product range, there are two types of LOM detection available **Type A** and **Type B**.+There is no regulatory need to install external anti-islanding equipment when disabling LOM in combination with a generator. To make sure. by installing signs and other means, that it is very clear to any installer working on the generator that he must also switch off, or otherwise disconnect, the inverter/charger system.
  
-All recent certified grid codes use Type B. On the MultiPlus-II models, **all** grid codes use Type B, and Type A is no longer used.+=== Safety notes Utility connection ===
  
-**Type A** is the strongest form of LOM detection resulting in the quickest detection time. It requires a low impedance connection to the grid (shortwell sized cables)LOM **Type A** will not work with generators.+Disabling the LOM on an input connected to the grid is only allowed when other external safety equipment is installedby means of an anti-islanding safety device. Victron does not make such producs. A common brand is Ziehl.
  
-**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.)//\\ +Make sure to comply to local rules & regulations - this is a critical safety issue.
-On generators, and also with installations having 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.+=== Screenshot of LOM settings ===
  
 +{{ :ve.bus:grid_code_compliant.png?direct |}}
 +
 +==== 2.7 Background: LOM detection Type A and Type B ====
 +
 +Within the Victron product range, there are two types of LOM detection available: Type A and Type B.
 +
 +All recent certified grid codes use Type B. On the MultiPlus-II models, **all** grid codes use Type B, and Type A is no longer used.
  
-==== Disabling LOM ====+**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.
  
-Besides choosing Type and B, it is also possible to disable the LOM entirely. +**Type B** has a more soft approach and a slightly longer detection time. Type 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.)//\\ 
-Note disabling the LOM on an input connected to the grid is only allowed when other external safety equipment is installed.+On generators, and also with installations having a relatively high impedance mains connection, Type B will work better than Type A.
  
-Disabling the LOM on an input connected to generator can be done, but then other methods / warning signs must be provided. Ensuring that any installer that will work on the generator will make sure to also switch off or otherwise disconnect the Inverter/charger system.+For generators on which also Type B does not work, see Disabling LOM.
  
-==== 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. 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.
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 {{ :ve.bus:grid_code_compliant.png?direct |}} {{ :ve.bus:grid_code_compliant.png?direct |}}
 +
 ===== 3. Example configuration in VEConfigure ===== ===== 3. Example configuration in VEConfigure =====
  
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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.
  
-More information here: https://www.victronenergy.com/live/multiplus_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? ====
  
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-===== DISQUS ===== 
-~~DISQUS~~ 
  
ve.bus/grid-codes-and-loss-of-mains-detection.txt · Last modified: 2020-07-21 14:52 by mvader