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UFLS and UVLS models cannot work together?

Hello,

I'm working with a simulation focusing on load shedding methods, counting on load relay models, LVSHBL and LDSHAL.

Firstly, I found that only on load relay model can be applied on a single load, but I can configure both at the same bus by setting specific load id for one of it while setting no load id with a asterisk for the other. I don't know whether that would work because I haven't run it yet.

Secondly, this is what I met, I configured LVSHBL for each load bus and a LDSHAL model for All, but only LVSHBLs work even the frequency decreased beyond the shed point of LDSHAL. I delete all LVSHBL models and run again, then UFLS occurs. At last I exchanged the models, LDSHBL for every bus and LVSHAL for All loads, then simulation shows only LDSHBL works.

So, does it mean that only local load relay models can work, then the models set on the level of Area, Zone, All loads will be disabled?

Thank you for any help.

Linzhi's avatar
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Linzhi
asked 2017-07-06 22:09:46 -0500
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See Chapter 21 in Program Application Guide Vol 2. There is a precedence order: bus, owner, zone, area and all. A model applied to a bus will take precedence over all conflicting models applied to any other subsystem in which the bus exists.

A precedence order is provided to accommodate conflicts in element identifier as well. A data record that introduces a subsystem model with a specific element identifier will take precedence over a subsystem model with a wildcard (’*’) identifier.

perolofl's avatar
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perolofl
answered 2017-07-07 01:43:30 -0500
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Thank you very much! You're really a master. I noticed that by applying models in different level and with a wildcard (’*’) identifier or not. Sadly the conflicts are not wanted and both UFLS and UVLS are needed in simulation. So, temporally I chose to write the function UVLS myself.

Linzhi's avatar Linzhi (2017-07-07 01:48:35 -0500) edit

Moreover, I will replace the UFLS models by my code for more specific and flexible study, which even user-written models cannot behave. BTW, why is the precedence order necessary?

Linzhi's avatar Linzhi (2017-07-07 01:50:28 -0500) edit
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