Recent content by Okpower

There are 2 main public explanations or theories: 1. Virus infecting the control system or hacking, EMP attack on transmission lines (!!??), and physical attack on main transformers similar to sabotage on Sillicon Valley substation...

Hello everyone: How credible is that a general blackout could be caused by a virus infecting the control system of a hidrogeneration plant with 20 electric generators? And what about electromagnetic weapons disturbing electric transmission lines? Is that possible? Regards

In fact, there will be two 20 MVA generators in parallel, feeding a 15 MV Petrochemical plant, and exporting the rest of the power to an 115 kV infinite bus. By now, I guess that I will apply the principle "Less is more". From your answers, an automatic OLTC may complicate the stability, and...

Dear All: I am considering to connect a 13.8/115 kV transformer to a 20 MVA Gas Turbogenerator (13.8 kV). The turbogenerator has an automatic system to regulate the reactive and active power. The questions are: 1.- Do I have to use an automatic transformer tap changer to regulate the voltage...

Thanks for your answers. Actually, I could use a good approach, for just initial investment (cost of the XFR and the TG) e.g , "the option 1 could be 200% the option 2" or "the 20MW turbogenerator cost the same than a 40 MW XFR". Jghrist, the 40 MW XFR could be installed to have future power...

Hi all: I have to do a presentation for the management team about a comparison between two options for a petrochemical plant electrical feeding: 1.- To buy and to install a 40 MW, 34.5/13.8 KV XFR with its correspondent 34.5 KV transmission line (3 Kms), to feed the main substation. 2.- To...

Hi all: I am involved in the procurement of about 20.000 meters of cables to be installed in a new Oil refining Plant. The contractor that is doing the design of electric system advised us to specify the size of cables in mm2, because there are more cable suppliers that handle this unit. At...

MJCronin: As Electrical Leader, I do think this is a serious issue to handle. I would prefer to have ground voltage just 0 Volts, not 10 or 15 volts (that would be the voltage that cathodic protection could put in grounding elements). In any case, which are the solutions or the alternatives...

Hi all: I work in the design of a new gas plant. Yesterday in a technical seminar, my boss proposed me to protect the grounding grid of the new plant with cathodic protection. I think it is unuseful, and not common practice. But I want to know your opinions in case that the proposal becomes in...

Hi all: I am looking for information about the main comercial current ratings of vacuum breakers for 13.8 KV (prices will be excellent too). I need to feed eight areas (3 to 6 MVA each) of a plant in 13.8 KV, but i dont want to use 1200 A breakers, that seems to be the most common rating, but...

This is a new project, for a new plant. And actually, it is difficult propose a 460 V motor for that power, because, the motor shal be capable to start with direct voltage.I have read about some "new" arrangement to control flow with several breakers, a small control logic and just 1 VFD to...

Thanks itsmoked: Just to clarify, I am thinking in just 1 VFD..(1 pump will be driven by just 1 VFD)900 HP, 675KW. The second one will be operated directly to line, and the third one will be just in spare.

Hi all: I am involved as electrical engineer in the designing of pump system for loading refrigerated products (PROPANE, BUTANE) to ships. This system will have a wide range of flow quantity since will be many different ships with many different capacities and flow rate limits. I am proposing a...

Hi all: I have 2 questions for a new oil plant electrical system design, about Power Quality Meters: .- How valuable is to install a permanent Power quality meter in the new plant? .- Where should this device be installed (Control rooms, main substations??) I found some tips from the web...

Hi all: I am doing a design for a 13.8 KV Substation. There are six incoming lines in 13.8 KV. Two of those incoming lines will come from 34.5/13.8 KV XRF's. Besides there are 20 outgoing lines in 13.8 KV. I want some suggestion about what kind of 34.5 KV breaker i should use: outdoor...