Which software can be used to perform a visual time simulation for flexible conductors short circuit forces? I saw a paper online using ANSYS for rigid bus not flexible ones.
Is ANSYS an easy to use software with no experience? I have not used any dedicated FEM software before
Any clues?
I got a couple of fixed 300 mA miniature RCCB and wonder if there is a way to increase its sensitivity to anything near 30 mA.
The first think is to installed a capacitor to neutral across it but is there a way to alter the internal circuit?
In LV application, for personal safety if a 30 mA RCD/GFCI is fitted to the terminal load, would it matter if the equipment body/chassis is earthed/grounded or not for RCD operation if someone touch the faulty housing? (as long as it is not connected to the neutral).
It may be a code mandate to...
Working on a transformer grounding 11/.38 kV for a mining site and wonder if the LV fault level need to be controlled to achieve compliance with low fault current for trail cables and connections inside the mining area. The addition of NER seems a simple answer but give the mining loads are...
I could find a few literature/standards are provided about railway earthing, namely the EN 50122-1 & -2.
I wonder if there are other detailed resources/textbook discussing the subject.
Please advise
For the network hereunder, a ground fault at "F" will return to the source transformer neutral path indicated as path #"1". The equivalent zero sequence network indicate that all this current is going back to the Delta-Wye transformer between bus (A) and (B) as shown in path #"2".
It may not...
I wonder if there are much to mention about the required lug contact area for grounding conductors into steel structures and down conductors to lightning protection systems.
10 times the copper required cross-section area seems like a rule of thumb for some utilities when using steel structures...
I wonder if any came across deep rod soil investigation. Is there any guidelines, other than trial and error, on how to create a soil model (layers resistivity, thickness,...etc) from the deep rod (say up to 100 m) resistance log?
I am carrying out a grounding study for a distribution kiosk as the client requires 1 ohm combined Hv and LV resistance. The site is near to the sea but soil measurements show a deep layer of about 600 ohm.m which seems to the bed rock.
min. depth of water table is about 35 m deep however, the...
Seems a bit academic but the effect of multiple insulators in parallel in increasing the falshover probability is well documented in many papers (http://clumb.free.fr/WG11/docs/public/33_01TF130104IWD.pdf Clause 2.3)and this is the reason that a transmission line is usually having a lower...
I am aware of the 1 min. short time withstand power frequency voltage for insulators, however, I wonder if there is a formula for times less than 1 minute e.g.1 sec or 0.5 sec AC withstand voltage?.
A bit confused about the fault current reflection into the delta winding and line side if there is a ground fault at the wye grounded side with source at the delta side.
What I am aware of is that the delta is not permitting zero sequence current out of it and thus the line current at the delta...
I came to know that inductive voltage transformers are usually expensive for voltages higher than 100 kV, that is why a lot of utilities prefer to go for capacitive VTs at higher voltages but, is there any operational aspects? Would the added capacitance be susceptible to ferroresonance issues?
Have seen that for MV 33 kV line where shielding is usually not effective and I can understand that for a shorter pole, the earth wire is installed under the phases.
It was a bit strange to see this configuration on a 132 kV line with wooden poles, however, the OHEW is grounded at every...
It is common to see accidents with electrocution in developing countries when floods take place and lighting poles get touched by unsuspecting public.
Would the application of RCDs work well in this situation? sometimes underground feeder cables in handling pits are not properly insulated...
I came across cable manufacturer design report quoting a formula to calculate the required clamp spacing, however, no reference is mentioned for the formula.
Dynamic Force:
Clamp Spacing:
Where can I find the reference standard/publication for this formula?
I wonder about the practice at 66 kV levels with usually one substation (source) at 220/66 kV with the 66 kV side star neutral earthed, however, the (load) or distribution stations will have a delta or unearthed star 66/22 kV.
This is not the case with 220 kV or higher voltages where both ends...
Cable sheathes boned at both sides (solid bonded) have circulating currents while showing zero voltages to ground at both extremities, a voltage peak is experienced at the mid span.
I couldn't locate a formula to calculate that voltage peak.
I bet this is a bit similar to voltage peak...
Math wise the ground fault current is If= 3E/(Z1+Z2+Z0)
where E is the phase voltage, Z1 is positive seq. impedance, Z2 is negative sequence impedance and Z0 is zero sequence impedance. with transmission lines and cables it is common to assume that Z1=Z2=Z then If = 3E/(2Z+Z0).
The zero...
