Where do you think the LV current came from ? if not from the MV side ?
Asking to type test the fuse with each LV breaker is excessive --- This may be a ill-advised rule or standard borne out of some old tragedy in the past .. now becoming an unreasonable 'bureaucrratic' requirement for no good...
breaker contact parting in 1/4 cycle [blow apart contacts] are LV breakers. IS-Limter work in medium voltage. The transformer will isolate any of the issue you cited and allow the unfettered operation of the CL Fuse. Perhaps you should read up on this product first ..
We install and use this...
You are right that this CL Fuse solution has been succesfully implemented many times and many places all over the world --- Why I recommended it ... The product was specifically developed for this purpose. Perhaps you should read up on this first .
The IS Limiter type of CL fuse is a 'system' type of fuse application, very different from the CL fuse embedded in molded case breakers. The IS Limiter would be used far upstream of the low voltage systems.
Yes, you lose fault coordination. However the school of thought here is that when you...
A current limiting fuse would be able to avoid the voltage drop issue, plus the iron and copper losses of the reactor 24/7.
The current limiting fuse by definition limis fault current by interrupting very fast [typically within 1/4 cycle] and drive the fault current to zero with or without...
Hi, I am preparing to buy a netbook computer [those smaller and simpler laptop computers] in the coming holiday season. My purpose is to take it travelling with me. However, when I am home, I want to hook it up to a LCD display that I have and the conventional keyboard and mouse so I can work...
It is not a garment factory. The outputs are films, yarns and so forth that are the first phase of the textile industry. It is basically a petrochemical plant using steam extensively in the process. They up the pressure to generate before sent to the process.
As for WTG, you should know that...
rbulsara
The machine is 15MW and load is approaching 10MW. It is a textile plant so the load is mostly VFD drives. Yes, very sensitive to undervoltage. Yes, we are looking into segregating loads and perhaps a medium voltage UPS backup for the VFDs [about 5MW], but it is really expensive ...
rbulsara said --- The explosion in wind turbines is one example. The most notorious and problematic interconnection from a stability point of view is a WT farm, yet they are more easily accepted compared to some roadblocks thrown at proven interconnection for conventional DGs. This is because of...
davidbeach --- 60 degree ahead of synchronism may be good but is not that critical, as we can see from synchronism check relays --- that it will work as long as the phasor difference is within the allowable tolerance. But the real question is whether one can hold that sync or a few degrees...
PHovnanian --- Your understood the question correctly, and your suggestion to look into the turbine/generator trip necessity is a good one. Thanks.
ScottyUK --- Hi, you have been a long term valuable contributor, thanks. However, we are not trying to transfer to Cogen, we are trying to...
My big question is this --- there must be at least 10,000 CONGENs in this world, and we conceivably share this problem, really caused by the utility's unwillingness to allow us to sync and parallel the system .. Surely we all want to save the loads without any of them dropping dead .. There...
Your big problem will be the control loops necessary to maintain the desired relationship --- I agree.
This is why I came here to see if someone might say .. Hey, here's what we did and was successful .. Hoping against hope, I guess ..
Thank you dpc, I share your opinion that it is difficult to remain in sync most of the time.
byrdi, if the initiation of turbine trip and fast transfer occurs at synchronism, the Cogen spin-down and phase angle slip you referred to can be managed by fast transfer actions [Siemens and ABB swears...
The purpose of the exercise is to transfer the loads quickly to the utility source if there is a problem that trips the COGEN Turbine Generator --- without losing the loads.
If there is no synchronism between COGEN and utility, fast transfer may not be possible and loads will be lost even if...
Thanks. However, in general, can cogen steam T-G control be good enough to keep up with this constant fine-tuning control ? The utility source may be very stable, but loads may change from time to time.
The utilities in the world usually do not like co-generation systems of their customers to be parallelled to the utility own system. Many simply forbid it. However, when there is a problem and the customer paid to have a 'hot standby' source from the utility, they will allow a source transfer...
Hi,
I have been visiting India recently and found out to my surprise that they do not use copper in their substation grounding [they use steel cables and steel members]. A utility engineer is telling me that they are having ground potential differences that affect their SCADA equipment...
