Questions tagged [distribution-network]

Power networks of medium voltage (2kV to 35kV typically) that connect the higher voltage transmission system to most of the electricity consumers. This tag covers anything related to electric power distribution system operation, protection, maintenance and capacity upgrade.

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How do power grid operators regulate the power flowing through their networks?

My question: How do grid and transmission line operators regulate the amount of power flowing in their networks, both to utilize the network optimally and to enact delivery policies like those in the ...
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What does "CON LAY" mean when it comes to conductor stranding?

I am reading the book "Distribution System Modelling" by Kersting, and in the Appendix there is a Conductor data. Under stranding it says CON LAY for some conductors (like 250,000 AA). What ...
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RS-485 Network Topology with Backbone and Daisy-Chain Stubs [closed]

I am designing a RS-485 network and would like to know whether the configuration below would work. The transceiver I am using is the Maxim MAX485, with the master ad slaves hardwired to always ...
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Is Petersen coil in resonant network tuned also for capacitor banks?

Petersen coil is tuned every 2-3 minutes to compensate for a certain percentage of capacitive current in resonant grids during earth faults. But, if capacitor banks with ground connection are switched ...
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What does it mean when it says to use the same energy mix in this network? Also how do capacitors affect the short circuit?

Here is the network: There is generator G1 that is modeled as a coal-fired power station and generators G2 and G2 that are modeled as a hydropower plant. It is said that if i reinforce the generation ...
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How do you calculate the ABCD constants of a transmission line

[question I've been trying to solve this question for a few hours now and this is what i ve gotten so far from scouring the internet for similar questions inorder to be able to solve mine. My question ...
1 vote
2 answers
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Is there any way to estimate transformer's estimated remaining lifetime without testing the oil (or degree of polymerization)?

The common parameter for transformer health monitoring is testing the oil and sediments (N.B., there might be others I don't know). The insulating strength of oil is decreased due to faults, overload, ...
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2 votes
2 answers
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Do circuit reclosers of substations respond to any fault on the low voltage side of distribution transformer?

As I don't have any practical experience in power distribution networks, I'm pretty confused about a few things. Typically a lot of transformers are connected to an 11KV distribution line ( 11KV ...
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1 answer
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How are locations of power plant and distribution substation decided?

I'm trying to design a basic electrical system of a large island and I'm having trouble deciding for the site locations. The existing grid of the island has a diesel plant located near the town but I ...
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Transformer load

I have 50 kVA delta-wye transformer with 3 single phases secondary (line-neutral) delivered to 3 houses, So if one of the 3 houses drown more power would that affect another 2 houses, or each phase ...
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234 views

Understanding Electric Distribution Pole Anatomy

Can you please take a look at these two overhead distribution pole images (US and Canada) and let me know what are the 1,2,3, and 4 wires in each images? Can you also let me know what is main ...
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Delta-Wye transformer differential protection during external line to line faults [closed]

During these kind of line to line faults current flows in the faulted phases of the secondary and all phases of the primary as it is shown in the image. So now the currents in phase A are not equal to ...
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How much information would a network protector need to determine if a backfeed is due to feeder failure or power export?

Many downtown or otherwise densely built-up areas, as well as some major metropoles (much of NYC, most notably), use secondary network electrical service to maximize service reliability and keep ...
1 vote
1 answer
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Does anyone know what the nitrogen gas on this telephone pole is for?

I saw this out walking. The tank had a sticker saying it is nitrogen. I followed the brown hose up to the cylinder on the what looks like a power wire. I would think it is a non-air "bath" ...
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18 votes
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How can energy "physically" be fed back into the grid?

I have found some similar questions (below), but I am still having issues understanding what is "physically" happening when energy is "fed back into the grid" and the equipment ...
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1 answer
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Can we harvest energy from a Rogowski coil?

Can we harvest enough energy (4-5 watts of power) from a custom made Rogowski coil? The primary conductor is 33kV and has an average current of 10A. I'm aware of the induced voltage and the mutual ...
2 votes
1 answer
259 views

Do ordinary transformers need flyback protection?

Low voltage 12V relays driven by a microcontroller plus transistor need a flyback diode to suppress an inductive voltage spike when they are switched off. Do ordinary power transformers (say, at a ...
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Any tips for a new grad in power engineering in Australia?

I am close to graduating from EE at an Australian university. I've recently found a job in the electrical distribution field and I'm realising that I know close to nothing about the standards and ...
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Nodal voltage magnitude properties of electricity distribution networks

I am wondering how to know about an electric bus according to its measured voltage magnitudes (possibly and its corresponding real power injection profile). Following assumptions can be made: One ...
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Is it possible that the line frequency can change along the distribution network?

We use single-phase 220-230V~/50Hz here in Turkey. The line frequency may vary ±5%. One of my colleagues told me that he measured the line frequency in a factory (probably a customer's factory that we ...
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Where do I find electrical power transmission grid data?

I am looking for websites which provide datasheets of 3 phase electrical power transmission networks with information about their ...
1 vote
1 answer
527 views

Can anybody tell me what these three white boxes are at the bottom of the power pole?

Can anybody tell me what these three white boxes are at the bottom of the pole? And how can I tell the number of the circuits on the electrical power pole and what voltages they have? Also, can I see ...
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TN-S system neutral point earth resistance

According to many sources on the internet, a secondary neutral earth resistor is added at the distribution stations (transformers) to reduce the earth fault current. My question is when using a TN-S ...
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In a transmission line, does the real current interact with reactive impedances?

simulate this circuit – Schematic created using CircuitLab According to the diagram above, if real currents do not interact with reactive impedances, then reactive loads should not worry the ...
2 votes
1 answer
316 views

Return path for current flow in transmission lines?

We know that all current flow in loops, i.e. if they start at a source they must come back to the source. So for transmission lines, does the current that flow through our appliances in our homes go ...
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6 votes
3 answers
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How does current flow to the ground in Delta connection (Ungrounded) in an Earth Fault?

I'm an electrical engineering student and I'm currently in In-Plant training in Electricity Company of my country. Recently I visited an electrical grid. I got to know about Earthing transformer. I ...
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11 votes
4 answers
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Purpose of cylindrical attachments on Power Transmission towers

Attached below is an image of a Power transmission pole. What I am interested in is the cylindrical shaped objects attached to the transmission tower. Some other observations and relevant information:...
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Surge arrester placement in substation

Is it enough to place surge arrester on the terminals of the transformer in a substation, or every power line entering the substation should have its own?
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1 answer
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Why ship power distribution systems have no neutral?

What is the reason for this difference between the distribution systems of power companies and the systems implemented at ships?
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Convert kW generated per minute to kWh

I have the data of power generated by a solar panel per minute in kW. I need to calculate the total number of kWh generated per day. How do I do this? So far, I divided each value of kW by 60 and ...
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1 answer
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Precise definition of a "radial" electrical distribution system topology

I'm confused about what is meant by "radial" topology of an electrical distribution system. This site claims we can generally group electrical distribution systems into three classes: radial, loop, ...
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1 answer
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How do you close a switch on a high-voltage network?

This is something I've been curious about for a long time. Let's say you're a utility trying to connect two segments of a distribution grid. Both segments will have about the same frequency, because ...
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How to estimate/compute for disconnected neutral potential rise?

This is a different question, I want to know what could be the minimum distances between poles before the ungrounded neutral in one pole can create different potential from the other neutrals in other ...
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Regarding Power Market demand and supply

As I have read, that power supply should be equal to demand. As it can't be stored .So basically this means power is generated in real time. Consider an area where power comes from a Substation A, ...
2 votes
1 answer
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Edge betweenness centralities for distribution grids [closed]

Graph centralities like edge betweenness centralities are commonly used to study the vulnerability in transmission networks, can they equally be used to study radial distribution networks ?
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6 answers
3k views

Why am I getting shocked from "hot" line and touching "ground" (Earth)

So I live in an EU country and don't have Earth grounding for my house. Still I am getting shocked when touching "hot" line (220VAC) and standing on "ground" (Earth). How is this possible? From my ...
1 vote
1 answer
331 views

zig zag vs open delta

Can we use zig-zag connection of transformers instead of open delta in electrical distribution ? If yes, then which one is the more preferable compared to other and why ?
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Australian suburban power distribution

In Melbourne, Australia I see a lot of utility poles like the one in the picture below. There are power lines on two levels. Three lines on the top level and four lines in the lower level. I assume, ...
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2 answers
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Symmetrical three-phase power flow problem, √3

I have done quite a lot of research regarding the power flow problem for the steady state operation of an electric system. In many papers about the power flow problem the power flow equation are ...
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1 answer
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Approaching to Integral from Limit of Sum ->Finding voltage drop due to uniformly distributed load current on a distributor

As shown in the picture above, I want to calculate the voltage drop due to a distributed load. l is the length of the distributor; n is simply no of segments, n=l/Δx; I have written down the sum to ...
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Service Wire Burn

I have a Distribution Transformer rated 25kVA 14.4/240 kV installed in the system. One phase of the serving 3 phase line of our electric utility in 23kV primary side are faulted in Line to ground ...
2 votes
3 answers
623 views

Isolation provided by transformers

I have a few questions about transformers and isolation. I will describe my understanding (maybe wrong) and questions about them. Transformers provide safe isolation by disconnecting two circuits ...
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