Questions tagged [power-grid]
Refers to grids or networks that deliver electrical power in large scale, that is, networks for bulk power transmission. For smaller scale networks, refer to distribution-network or microgrids
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Why does reactive power change when a secondary source is connected?
When load was varying very little, PV supply was turned ON.
Inverters used can give power factor(PF) in the range of [-0.8, -1] and [0.8, 1.0]
Table 1 shows power requirement when only grid was ...
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1answer
45 views
What is the difference between commutation number and pulse number in?
My question is about bridge rectifiers in power electronics.
I guess the jargons are too vague, so i quote the exact definitions from my book which i don't understand at all:
m represents the ...
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0answers
168 views
Is the duck (curve) still a duck? [closed]
In 2013 the California Independent System Operator (CAISO) published this image, dubbed it "the duck curve", and took the internet by storm (or, at least the part of the internet that tracks trends in ...
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2answers
4k views
When a wind turbine does not produce enough electricity how does the power company compensate for the loss?
I heard once that when a wind turbine power plant doesn't produce enough electricity the power company's are sometimes forced to turn on a couple of jet engines in order to compensate for the loss, is ...
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1answer
55 views
What determines the phase difference between two voltages at an AC bus?
At an AC bus, the power flow is given by the following equation :
In normal operation, the voltages (V1, V2), as well as the inductive resistance (x), are constants. So the parameter δ defines the ...
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1answer
23 views
Peak Period Forecasting in electric grid
I am currently working on the day ahead load forecasting using a regression model over a microgrid level.
I wanted to know is there a way I can detect peak period i.e period where demand is high from ...
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1answer
34 views
Load Profile plot from Smart meter data
In electrical engineering, a load profile is a graph of the variation in the electrical load versus time.
I am currently working on Smart meter data having reading an interval of 30 min i.e power ...
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1answer
34 views
Distribution-side voltage regulation and Low voltage ride through (LVTR) curve
Nowadays, I see that photovoltaic systems have Low-voltage-ride-through capabilities. So in case of a fault, when the voltage is decreased, they remain connected to the grid and provide reactive power ...
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1answer
69 views
How much power do power stations in parallel supply?
In modern power systems, the power is supplied by effectively connecting multiple generators in parallel. However, not all these generators are equal, some stations supply more power than others (I ...
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2answers
350 views
Why is the socket voltage in Mexico 127V?
As per the title, this is a very specific figure. Is there a reason it's 127 instead of 120V or 130V?
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2answers
1k views
In North America, why is the wide prong neutral instead of the narrow prong?
The wide prong is neutral on 15 amp US power outlets.
Is there a reason it was designed this way, or could the narrow slot just as easily have been neutral instead? Was this design decision ...
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1answer
46 views
Connect a switching power supply to the EU grid
I just bought a switching power supply which is supposed to be connected to the power grid using three connections (Neutral, Live and Ground). Unfortunately, all common cables can be plugged into ...
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1answer
82 views
Reactive power compensation through grid connected inverter
I recently designed a bidirectional DC-DC charger for an Electric Vehicle (EV) battery.
I would like to focus on the inverter control. In this application, I designed the inverter to have unitary ...
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1answer
42 views
how could i decrease residual voltage of 11KV bus that Is created by direct online 9MVA induction Emotor?
We have power grid 11KV (bus A & bus B) with 2 incoming and one coupling breaker between them;bus A have a outgoing that feed 9MVA induction Emotor;
incoming A and B and coupling Equipped with ATS ...
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0answers
36 views
How do single-phase inverters know if they're in sync with the grid after they're in parallel?
How can one inverter, once its output is already in parallel with the grid, measure the phase difference between the grid and itself?
Any current or the variation in the current flowing on its output ...
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1answer
399 views
Why does a wind turbine deliver reactive power to the grid during no winds or when turbine is stopped?
An answer to a previous question explained that a turbine in stop mode may deliver reactive power to the grid. It also takes active power from the grid to run its control system, lighting system and ...
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1answer
208 views
Why does a fault lead to increased reactive power demand?
When we have a fault, say on one line out of three, the reactive power demands increase, which leads to voltage instability if the source can't provide it.
My question is, what causes reactive power ...
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1answer
88 views
Understanding power system lines and their capacity
First of all, I am no engineer so forgive me if I confuse concepts (or show lack thereof).
When constructing the power grid, I was wondering about the following:
Do engineers use 'standard lines' (...
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1answer
80 views
How do I keep DC voltage high in a building grid?
I'm trying to create an off-grid installation.
I have 200W PV panels, 20A charge regulator and two 150Ah, 12V batteries in parallel.
How can I keep the voltage constant through all the grid in the ...
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1answer
80 views
The materials used in an electrical grid going from power station to house [closed]
In getting an overview about how Electrical Grids work, I was hoping to connect the dots from voltage up to the materials (used in modern electrical grids).
I am wondering if one could outline ...
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2answers
186 views
Identification of a part on a power line's lightning arrester
I recently spotted an arrangement of wires on a lightning arrester on top of a power line. The power line is IIRC a 110 kV, 16.7 Hz, two phase line for railway systems.
The lightning arrester is of ...
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3answers
2k views
Do electricity meters contain inverters?
In Germany the low-voltage grid is 0.4kV whereas the plugs in flats have 230V. Who is responsible for this conversion? Smart meter?
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1answer
50 views
What may be the consequences of AC frequency variations on powerline network adapters [closed]
There has been several reports lately of variations of the main frequency of AC current in European households. What do you think could be the consequences on network signal when using network over ...
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5answers
12k views
Serbia, Kosovo power grid row delays European clocks. Why?
According to this article (and a lot more published today on the same topic), Kosovo electricity net production balance has decreased during the last weeks.
This has led to a small deviation of the ...
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1answer
72 views
How is the inverter connected to the grid?
I just finished circuit designing of an inverter which converts 440V DC to 230V AC. Now my manager asked me what kind of connectivity does it has.
I answered him:
"The current connectivity is AC as ...
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0answers
22 views
Low voltage grid frequency with renewable feed-in
If a low voltage grid's consumption equals to that grids renewable energy production, does it mean the transformator basically does nothing, like an open circuit? Are grid-tied inverters (smart) ...
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1answer
40 views
PV energy feed-in to the grid
I'm reading about integrating PV into legacy grids, and I saw the following scheme:
Left side is middle voltage grid, and right side is low voltage grid (400V AC). It is talking about communication ...
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1answer
83 views
What are important metrics of high voltage power lines? [closed]
Upfront: I am not an electrical engineer and therefore apologize upfront if I am asking a stupid question.
TLDR; What are important / relevant metrics of high voltage power lines that can be ...
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0answers
29 views
Very low network impedance close to 13th harmonic frequency
I carried out a frequency scan of an electrical network model with a proposed 220kV transmission line. Addition of this line lowered the system impedance to very low value (to 3 Ohms) at 13th harmonic ...
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0answers
75 views
Why did the Tesla battery in Queensland respond to grid frequency? Why isn't this stable? [duplicate]
The RenewEconomy article Tesla big battery outsmarts lumbering coal units after Loy Yang trips details the recently installed Tesla battery in Queensland Australia's response to a sudden change in ...
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0answers
56 views
Question on specific power grid drawing
does anyone know what the dotted lines represent in the following drawing of 230KV voltage lines and 230KV/66KV substations (blue-rimmed is under development; solid blue square is existing)? There is ...
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3answers
3k views
Why do underground cables “require a higher degree of reactive power compensation” than overhead lines?
I was reading a brag sheet for a certain company's giant transformers, and I came across this sentence:
Furthermore, in some regions, the existing over head lines are being replaced by underground ...
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3answers
128 views
Feeding energy to the power grid
I am doing a research about the electricity grid and a marketplace where neighbours can trade energy with each other.
I found out if your PV cell has excess energy you can with an inverter put it ...
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1answer
936 views
What is the purpose of the cylindrical layered conical discs in power stations? [duplicate]
You can see them everywhere. On towers of overhead lines, in power stations, converter stations, transformer stations, etc... Sometimes they are rubber, sometimes metallic, sometimes glass, sometimes ...
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1answer
53 views
What is the range of a direction protection relay?
I am modeling a hypothetical backup protection system for a power transmission grid and need to know if a directional relay can detect a fault if there are multiple lines and buses between the relay ...
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1answer
47 views
Looking for time-series grid data set
The electric power grid consists of many buses, with generators and loads connected to each bus.
The so-called operating point of the system consists of the voltage magnitudes, Vn, and voltage phase ...
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2answers
88 views
Power system - Economic dispatch
Quick concept related question, I have a system with 5 generation units and I have to find the maximum demand that the system can support and still be N-1 secure.
their max outputs are:
Unit A= 155, ...
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0answers
2k views
Detecting AC power flow direction [closed]
I'm willing to design an AC power meter, which can measure power from a solar inverter to the utility grid and vice versa. I am using a grid-tied solar inverter to supply the load. This meter should ...
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3answers
67 views
Proper inverter VAC output when tied to grid
I live in a US state which encourages home-owners to install their own renewable system and feed the power back into the commercial grid. The inverters take their phase clock from the line and ...
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2answers
210 views
What's the logic behind the load simulation in Simulink's power_microgrid example?
I'm trying to understand the Simulink example "Simplified Model of a Small Scale Micro-Grid" in order to build something similar. If it's included in your Simulink version you can access it by writing ...
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2answers
157 views
How is electricity from a power station added to the grid?
If I construct my own solar powerplant to add my output to the power grid how is it done technically ?
What are all the steps I need to go through ? (Not regulatory procedures.. But would still be ...
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2answers
956 views
How much electric power can we generate at home by use of treadmill like devices and dynamo? [closed]
I goto gym to burn about 600-1000 KCal. Instead, can we conserve this and be less dependent on grid for basic lighting and TV and other electrical energy needs at home? What are challenges today?
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2answers
800 views
In the USA, the grid transmits power at/around 60Hz. How big of a frequency deviation can the grid handle before relays trip and cause a blackout?
I understand that small frequency deviations will result in automatic load shedding or other control actions to restore system frequency, but when does a blackout occur? When the deviation exceeds + ...
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1answer
662 views
On-grid solar system - how to control power out from solar system to grid? [closed]
If on-grid solar system is connected in parallel with grid,
solar system give power to the grid when local (at house) consume power less than generated power from solar system.
The question is:
When ...
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1answer
132 views
Grid tie inverter power factor
After installing a grid tie inverter (GTI,) the power factor dropped from 1 to .85 over the last week. My loads are a combination of inductive and resistive.
I have an option of setting my GTI to ...
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2answers
85 views
Robustness of voltage grid system or railway grid
Can somebody explain to me how robust the high voltage grid systems and railway grid systems are against shorting? For example, if a thinner bare wire or cable falls on two wires of the HV cable, will ...
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7answers
3k views
Staying in Phase On The Grid
I have been an EE for over forty years and never did find out the right answer to this one....
How do power-stations and transformer switching stations ensure that the power they are feeding into the ...
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1answer
3k views
How to deal with optimal power flow problem in MATLAB?
I am writing an optimal power flow (OPF) program. OPF is an optimization problem in which some decision variables like Generation, Load dispatch are adjusted in power flow program so as to minimize ...
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1answer
199 views
Grid voltage swell and sag, what happens to harmonics?
I know that when a load draws too much power the voltage of the grid at the fundamental frequency begins to sag. Though my understanding is that loads can't use the power generated by harmonics, so ...
