ve.bus:grid-codes-and-loss-of-mains-detection
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ve.bus:grid-codes-and-loss-of-mains-detection [2020-07-20 17:01] – [LOM detection Type A and Type B] pba | ve.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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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, | 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 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 | + | 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 |
+ | In certain situations, the inverter/ | ||
+ | |||
+ | Make sure to also read [[ess: | ||
===== 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/ | + | LOM is an automatic process that detects a loss of the mains/ |
- | ==== 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/ | To detect a loss of mains, the inverter/ | ||
- | 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/ | + | When connected to a generator, or to a grid with a long extension cable or long ‘last mile’ cable, |
- | ==== 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? ==== | ||
- | By temporarily disabling the LOM, one can identify that the LOM is causing | + | ==== 2.5 How to identify if LOM detection causes overload issues? ==== |
+ | |||
+ | By temporarily disabling the LOM, one can identify that the LOM is causing | ||
Open VEConfigure, | Open VEConfigure, | ||
- | Save the settings, and wait to see if this helps. In case it does help, see next section. | + | Save the settings, and wait to see if this helps. |
- | 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, | + | In case disabling |
- | ==== What to do when LOM detection causes issues? ==== | + | |
- | The previous section explains how to identify if LOM causes an issue. It can cause overload | + | NOTE: for LOM to cause overload |
- | The solution is then to make for a better connection to the utility - but as that is often quite hard to achieve, here is another solution: keep 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. | + | ==== 2.6 Disabling |
+ | There are a 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) | ||
- | ==== LOM detection Type A and Type B ==== | + | To disable |
- | Within the Victron product range, there are two types of LOM detection available | + | KNOWN LIMITATION: Note that, even with the LOM detection disabled on an AC input, the inverter/ |
+ | |||
+ | === Safety notes - Generator === | ||
+ | |||
+ | 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/ | ||
+ | |||
+ | === Safety notes - Utility connection === | ||
+ | |||
+ | Disabling the LOM on an input connected to the grid is only allowed when other external safety equipment is installed, by means of an anti-islanding safety device. Victron does not make such producs. A common brand is Ziehl. | ||
+ | |||
+ | Make sure to comply to local rules & regulations - this is a critical safety issue. | ||
+ | |||
+ | === Screenshot of LOM settings === | ||
+ | |||
+ | {{ : | ||
+ | |||
+ | ==== 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. | 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. | ||
- | **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/ | + | **Type B** has a more soft approach and a slightly longer detection time. Type B has been type tested and approved for most Multi/ |
- | 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. | + | 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/ | ||
- | ==== Disabling LOM ==== | + | On generators, and also with installations having a relatively high impedance mains connection, Type B will work better than Type A. |
- | Besides choosing | + | For generators on which also Type B does not work, see the Disabling |
- | Note disabling the LOM on an input connected to the grid is only allowed when other external safety equipment is installed. | + | |
- | 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/ | + | ==== 2.8 Grid codes and Type A and Type B LOM ==== |
- | ==== Grid codes and Type A and Type B LOM ==== | + | At the time of writing all Grid codes use Type B or "LOM disabled" |
- | 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. | + | 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 " | ||
{{ : | {{ : | ||
+ | |||
===== 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 | + | Note that it is also possible for some generators that it is not accepted by the inverter/ |
+ | |||
+ | More information | ||
==== 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.1595257262.txt.gz · Last modified: 2020-07-20 17:01 by pba