My suspicion is this is not an ethical move, but I was curious what others thought.
I am a PE in one state in the US, working with a consulting firm. I intend to move to another company in another state in the near future. I would like to get licensed in this other state before I send...
I thought I'd open a thread to discuss ideas for hosting capacity evaluations for distributed energy resources (DER) on utility distribution systems. I know it'd be of great use to me, and perhaps to any other planning engineers out there. First, I'm curious, is anyone thinking of how these...
In sizing temporary protective grounds for distribution and sub-transmission voltages, I'm debating how to consider lightning. Would it be appropriate to estimate a current stroke and the associated voltage developed across the conductor/person? I'm leaning toward thinking that it is pointless...
Hello,
I'm trying to wrap my head around something but can't quite get there. Suppose I have two separate ground grids in close proximity that are connected to each other by conductor. One of these grids is bare conductor, and one is insulated (both have bare ground rods). If I'm the area...
Does anyone have any thoughts on how a substation ground well might be modeled? I'm using ETAP, which does not have a formal procedure or element to model one. I know the overall grid resistance, and I know the resistance of each well.
Ultimately I'm trying to determine GPR, touch and step...
Hello all,
I work for a consulting firm in the utilities sector. I recently got my PE, and am hoping for a bonus. The thought occurred to me though, it so happens I intend to purchase my first home next year, and some extra cash on hand would be useful. I considered asking for a bonus...
Hello everyone,
I'm thinking I must be making this too difficult, but I'm not able to figure it out. I have within a function a loop that I want to run continuously for some period of time, and plot the results. I've tried to make a variable t within the loop. At the end of the while loop, I...
Has anyone given any thought to the appropriate arc gap or working distance for voltages over 15 kV for arc flash studies... say 34.5kV or 69kV? The suggestions by OSHA seem too small in my opinion. If you consider arc gap for 69 kV, they suggest an arc gap of 0.1* V_LG (approximate dielectric...
Does anyone have any good references on DG interconnection studies? I'm thinking primarily PV, but any DG really. Most of the books I've seen are on designing solar arrays and inverter integration. I'm at the stage where someone has designed the solar array and selected the inverter... I must...
Does anyone know if this circuit has a name, or better still have an idea of how to solve? If I have a known current and voltage I1 and V1, how is the current through each impedance element determined? I've searched through filter design literature without success, and have attempted deriving...
Perhaps I've been out of school for too long, but I don't recall how to solve this circuit. It appears to be used as a filter topology, so someone must know, but I can't find it. I want to be able to calculate voltage and current at each node.
Anyone have any tips on where to look, or where...
How do you guys handle determining three phase arc flash boundaries using ARCPRO? Single phase arc flash boundary can be achieved with trial and error, continually adjusting the working distance until your incident energy at that distance is equal to 1.2 cal/cm2. But what about three phase...
I've run across a few multipliers in converting single phase arc flash energy to three phase, and vice versa. ARCPRO gives a range of multipliers, the most conservative being three phase energy is equal to 2.2 times single phase. Duke Power suggests that the factor is 2.8.
Any idea where...
All,
A thread titled "Blinking Lights" came up in the Electric motors, generators & controls engineering forum. There was some disagreement over whether a power factor capacitor in parallel with a motor would result in increased or decreased inrush.
Looks like the consensus was decreased...
All,
I've searched the forums and was surprised to see this hadn't been addressed, so if I've overlooked something, please let me know.
I have a three phase wye-delta 12.47kV to 240V with a tap on one delta leg for 120V. The wye is ungrounded, and the tap on the delta is grounded.
How...
Hello,
I am a system planning engineer at a consulting firm for electric distribution utilities. Among my tasks is to develop construction work plans, identifying future projects, line upgrades/additions, etc. These work plans are used for future spending estimation and purchasing... the...
All,
Is there a standard or reference out there describing neutral current or voltage/current imbalance limits (three phase 4.16kV wye overhead, United States)? I'm working on a study and am finding imbalance as much as 30% which I know is high, but I'd like to be able to point to a standard...
I've come across a Westinghouse CO-8 relay for a 13.8kV feeder. A testing company has covered up the nameplate of the relay with their test data, but I'm unsure what it means. The paper reads:
120A P.U.
360A -48~
660A -INST
This is fed by a 100:5 CT, so the pickup and the...
All,
I've posted a few questions related to job searches, and have yet another. I have sent my resume to a few companies this week, some large, some small. For one of the smaller companies, I have corresponded with an HR/secretary person, and she told me that she sent my resume to the head of...
All,
I've recently applied for an engineering position at a large utility (approximately 700 people). I submitted a resume and cover letter online, and they will get back to me if they decide I'm worth considering.
Should I give them a follow up call in a week or so? They're such a large...
