Timeline for Protect Inverter from Transformer's Inrush Current
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Apr 2, 2019 at 12:40 | comment | added | D.A.S. | Inductors do not surge on startup unless they saturate | |
| Apr 2, 2019 at 12:39 | comment | added | D.A.S. | WIth load disconnected, does transformer surge? There ought to be no surge as it is inductive and Iexc = 10% of I max rated . Otherwise if it has a surge , it is from core saturation from remanence which reduces to steady state excitation current of ~10%. OK? | |
| Apr 2, 2019 at 8:10 | comment | added | thece | I don't understand what you mean "with no-load". Do you mean magnetizing the TF without load and the close a second switch, on the secondary? This has not been tested, but I don't think it will make a big difference. Do you mean something else? | |
| Apr 1, 2019 at 20:08 | comment | added | D.A.S. | So you have verified this surge exists even with no-load. Is it possible the load is asymmetric on polarity thus magnetize the core from secondary. | |
| Apr 1, 2019 at 19:54 | comment | added | thece | It is 100% from the magnetization current of the tf. It has nothing to do with the RES. Look at the scenario I present above: RES is feeding the small load (lets say 500kW) and we are at steady-state. Then, the switch of the big load closes and it starts at full power. No soft-start of the load is possible. | |
| Apr 1, 2019 at 19:21 | comment | added | D.A.S. | Is this a problem with RES? lacking a soft start? | |
| Apr 1, 2019 at 19:14 | history | edited | D.A.S. | CC BY-SA 4.0 |
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| Apr 1, 2019 at 18:56 | comment | added | D.A.S. | So you must determine if it is caused by loads or Remanence ( no load) | |
| Apr 1, 2019 at 18:54 | comment | added | thece | Nope, unfortunately it starts at full power. This was the first thing we tried to do :P | |
| Apr 1, 2019 at 18:53 | comment | added | D.A.S. | Can the startup load be regulated externally? Motors are often 5x but can be cured by VFD's or sequencing multiple loads. But this load induced then it won't cure Remanence saturation. | |
| Apr 1, 2019 at 18:51 | comment | added | thece | The magnetization current is "independent" of the load, but the transformer's "dimensions" are not. Bigger load needs bigger transformers, hence bigger inrush current. This technique from ABB seems interesting, so I will look further. Thanks! | |
| Apr 1, 2019 at 18:50 | history | edited | D.A.S. | CC BY-SA 4.0 |
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| Apr 1, 2019 at 18:39 | history | answered | D.A.S. | CC BY-SA 4.0 |