I’d like to get your thoughts on the best grounding practices for overhead line structures equipped with surge arresters. My understanding is that surge arresters should have the shortest possible path to ground via a dedicated ground wire. Additionally, other pole-mounted equipment (power...
Can someone point me to the industry references for the typical outage rates for overhead powerlines? I am performing the reliability assessment study for our distribution lines and would like to have a reference to benchmark against.
Is there any merit to conduct HI-POT on the autoreclosers during periodic maintenance? Some vendors maintenance manuals recommends it and some leave it for users to decide. Our challenge is most of our reclosers are mounted on the poles so conducting Hi-POT on these reclosers is bit of...
We are not a utility, but we manage a large network of distribution and transmission lines that feed critical loads. Recently, we experienced some lightning-related outages on our 34.5kV circuits. Upon investigation, we found that the footing resistance of the structures was quite high, leading...
I recently got in debate with a coworker on the right way to connect the surge arrester across the terminal of the equipment it is suppose to protect. I have attached a sketch for both options which came under discussion. To me both options are electrically same with option 1 offers a shorter...
Anyone here with the experience of using arcing horns on distribution voltage (35kV) overhead Powerline insulators? We have one old line which has ceramic insulators with the creepage distance not suitable for the area, so we are evaluating the option to replace the insulators with the polymer...
Hello all..... we have 13.8kV distribution line which runs near the costal area and we recently experienced few flasover where the inusulator show arc marks on the top shed and the bottom shed only. Installed insulators are composite type with silicon rubber shed and 40mm/kV creepage distance...
Hello Everyone.. what are the typical re-commissioning electrical tests for overhead powerlines? I understand for long distance HV (230kV and higher) you would normally perform phase sequence/rotation check, sequence impedance tests, conductivity tests and footing resistance tests. My question...
Hi All..... We have two old 115kV line running parallel to each other with insufficient clearance between each other. During windy season, we get outages on these lines as conductors of one line come in contact with the structures of the other line. We are evaluating options to fix this issue...
Hello all...... We have a situation where we need to load ACSR conductor in 120-130 deg C range. I am trying to figure out how long (hours, weeks, months?) a conductor can be operated above the normal operating temperature before aluminum starts to anneal and conductor strength gets impacted. If...
Anyone here has experience with measuring ground resistance of tower/ structure footing? What testing tools are typically used by utilities to determine the footing resistance? We recently had few back flashovers on our power lines, so we are doing the root cause analysis and starting with the...
Hello Everyone......... We are designing the 35kV power-line in the area of high bird activity and one of the suggestions presented from the stakeholders was to use bigger line-ground clearances on the structure which are mostly bird targets (like corner structures or structures with crossarms)...
Hi Guys........ We have site contractor installing the 35kV cable underground from the riser pole to the substation yard. Does anyone know about the guidelines for any slack allowance in cable on each side of the dip to account for earth freeze and thaw? I assume we would need to allow for cable...
My understanding is that either lightning flashover(BIL) or switching surges(BSL) govern the required phase to ground and phase to phase clearances based on the system voltage levels. Based on some reseach , it seems like at the voltages below 220kV, lightning performance dictates the required...
Does anyone know which one is more suitable for outdoor application, hot dipped tin platted hardware or just tin platted? I am using the electrical connector for the substation application and it's a bronze connector which comes either all Tin platted or hot dipped tin plated.
I am designing 240kV slack span from one substation A-frame to the other substation A-frame. Lightning protection is provided by the shield wires. The local utility practice is that they don't allow grounding of shield wire on the substation A-frame structures by installing the insulator in the...
I hope everyone is keeping safe. Question came up from site contractor about bonding of hardware and got me thinking........
We have 25kV OH line without shield wire protection so it doesn't have any ground downlead and ground rods etc. Contractor is asking if they need to bond any metallic...
I am wondering if there is a minimum horizontal distance requirement between Pole base (directly buried wood pole) and the guy wire anchor. I have seen few utility standards where they specify minimum 3m between each anchor, which I guess is to ensure the ground around each anchor is not...
I am wondering if anyone knows how to calculate the length of the wire between two points when the other variables like the tension, sag, weight of the wire are known.
