Questions tagged [power-grid]
Refers to grids or networks that deliver electrical power on a large scale, that is, networks for bulk power transmission. For smaller scale networks, refer to distribution-network or microgrids.
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How is power taken drawn from a home battery/inverter in preference to mains/grid power [closed]
I have a home battery energy storage system with some solar panels, the solar panels don't provide enough energy for me to be completely off grid (especially as I'm in the UK where the weather is ...
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How can overproduction of electric power be a problem to the grid? [closed]
Recently, in Brazil, we had a major shutdown of the electrical grid of the entire country (wich is mostly interconnected across the majority of the states). After official investigation, the culprit ...
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Simple transient simulation model for synchronous generators
I am writing a simple transient circuit simulator as a personal hobby/experiment. My ultimate goal is to develop a simple 2D game for teaching/learning concepts of power systems in an intuitive way. I ...
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Why don't we use the third harmonic in power transmission?
For some high power high voltage lines DC is used with the advantage that sinus wave AC obviously doesn't use the line to it's maximum capacity at all times. To correct this, we could use square wave ...
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Effects of Solar Distributed Generators on Utility Grid
The figure Below is a test block diagram that I would like to model and simulate in DigSILENT PowerFactory Software to analyze the effects of SDGs on the utility grid’s Power losses, Voltage ...
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Dual-Power Sourcing for 15MW Electrolyser: Wind Farm and Electrical Grid Feasibility [closed]
I am part of a team working on a 15MW electrolyser project comprising six 2.5MW containerized electrolysers. This setup will be positioned near a 20MW wind farm, and there is also the potential for us ...
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Why is there loss of power between solar inverter and utility meter?
I have an on-grid 10 kW system installed with two-way recording meter. Recently I have noticed that units generated as shown by inverter are more than the units recorded by utility meter. Previously, ...
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What are these circular basket-like structures on a high voltage transformer's insulators?
Wikimedia commons contains this public-domain image of a high-voltage transformer of the Tarza power plant in Iraq, taken by Marvin Daniels in the U.S. Army:
There is much I do not immediately ...
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Where can I find synchronous machine datasheet?
In the laboratory where I work, we have developed our own MATLAB library for simulating transient response of power systems, and I am currently working on some simulations of IEEE 9 bus system.
I was ...
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Conversion from DQ0 to dq0 and vice-versa
I have been working with multi-machine power systems, and I have been struggling with the transformation between the dq0 and DQ0 frames. I will first introduce my understanding of these frames, and ...
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How to ramp up a factory consuming a lot of energy?
Can you please explain how to manage the process of ramping up a factory with a big electric consumption?
I am wondering how it is possible to balance the grid during the start up phase of a big power ...
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What does this odd-looking contraption on the back of an electrical power utility pickup truck do? [closed]
Spotted on a Con Ed truck driving around Brooklyn, NY streets late at night.
Some kind of EM field sensor maybe?
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Bonded ground, other line reading is 0 volts
Can someone explain this data to me:
All machines connected to the grid are normal.
Line 1 to line 2 = 230 volts
Line 2 to line 3 = 230 volts
Line 3 to line 1 = 230 volts
Line 1 to ground = 230 ...
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What is this device on an electrical pole?
I see this setup all over my neighborhood and am curious about one of the components. The houses on the outer edge of the neighborhood seem to get their electricity by tapping into one of the phases ...
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Are these transformers or giant capacitors?
I sometimes see these devices along power lines when I'm driving and was wondering what they were. They look just like the regular transformers that I see on top of electrical poles, but it seemed ...
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What is the relationship between a power line's voltage and the amount of power it can transmit?
I am considering a classic power distribution network using 3-phase AC power. There is usually power lines of various voltages ranging from 10kV to 400kV. These values change country-by-country. For ...
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Is an EMP weapon a real threat to power grids?
I do not see how an EMP is realizable. The idea is a nuclear bomb detonated high enough will release a strong enough EMP to take out a country's power grid without damaging infrastructure. In my ...
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How does a power generator control its output to the grid?
I found this answer: On-grid solar system - how to control power out from solar system to grid?
But I would like to know a little more about the details and the dynamics of the inverter. As an example,...
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Can a generator in an electrical grid be destroyed by disconnecting the power at a distant substation
I've read that if the length of a transmission line is a quarter wavelength then an open circuit at the sink would appear as a short at the source.
Consider a real electrical power transmission line ...
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How can earth be connected to neutral?
I recently installed a solar inverter in my house and learned that earth must be connected to neutral. I am very puzzled by this, since AC changes direction of current flow, so according to me, there ...
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Is it possible to have a current higher than the transformer short circuit one?
I am a student and I want to understand the following aspect.
I know that protections and whatever devices installed in the grid must tolerate a current higher than the short circuit current. At the ...
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How do grid tie inverters sense the mains phase and quality and at the same time feed current into it?
Grid-tie inverters synchronize the phase and also check the quality (frequency, magnitude) and shutdown in case of errors to prevent what's called islanding, i.e. to prevent feeding current to network ...
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Power grid dynamics: Does increased power use = increased fossil fuel use in grid?
Say I come home on a hot day and crank my AC full blast (colder.) The grid is powered by wind, solar, hydro, coal, and natural gas. The additional power required by my cranking up the AC cannot be ...
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How does lightning increase the voltage within a substation (how does current increase voltage)?
I'm new within the power industry and was introduced to a scenario I had a question about. So, while discussing the need for surge arresters came up, we began talking about lightning. I know that ...
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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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How do large electrical grids stay in phase?
I am a math student with some background in physics so apologies if the question is naive - but I'm trying to understand how large electrical grids like the Eastern Interconnection maintain locally a ...
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Grid Voltage Ride Through using PSSE
I am trying to simulate a low voltage ride through (LVRT) lagging case (Qgenerator = max). The inverter seems to be going to momentary cessation, and although the output power at the inverter ...
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What happens if there is a reactive power imbalance in a large grid?
Consider the Continental Europe power grid.
Supposing there is a 1 GW of active power imbalance in the grid. This would lead to a frequency drop/rise in the whole grid at steady-state.
What happens ...
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What is the reason for these utility poles with a 6-sided hole in the middle for conductors
What would be the technical (Electrical, structural, safety) reasons for a utility pole like those shown below? This picture was taken in Arkansas and is what I assume to be 3-phase power. Note how in ...
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What happens on a DC-DC grid connection after a perturbation in the synchronous grid?
Consider the Continental Europe synchronous grid. This power system has some DC-DC connections with other countries (for example one with Great-Britain). Suppose now there is a sudden big outage ...
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Do static generators maintain a constant voltage at the terminals?
Do static generators maintain the terminal voltage constant like a synchronous generator does? If not, are they at constant current? With static generator I mean photovoltaic systems connected to the ...
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How to get a static generator starting from a synchronous one?
I want to model a static generator (a photovoltaic one) inside a simulation tool. This simulation tool has no static generator (it is quite new and not user friendly).
My idea was to model a ...
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Is the reference voltage for voltage control the RMS between the three phase voltages?
Suppose to provide voltage control with an AVR connected to a synchronous generator. A voltage reference is compared with the output terminal voltage of the generator, and the error between them is ...
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Is the same overcurrent relay used for both phase-to-phase faults and 3-phase faults?
In MV grid with no distributed generators, 50-51 overcurrent relays are used to detect both phase to phase faults anf 3-phase faults.
In Italy, time independent characteristics are used inside these ...
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Reactive power fluctuation
We have 6 Caterpillar gas generators 3520c.
One of them when synches with the grid. Its kVAR fluctuates over wide range and the aux voltage too and the excitation volt and current. We checked AVR and ...
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Transformer ratio of a transformer that connects a generator to a MV grid?
Inside my one-line diagram in which I am studying some properties of the medium voltage grid, I want to connect a generator to the MV busbar to study the hosting capacity. Therefore there is not a ...
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Admittance matrix when switch is open
In the following there is an example of an admittance matrix.
https://en.m.wikipedia.org/wiki/Nodal_admittance_matrix
If y13 had a switch and it is open, what happens to the admittance matrix?
Thanks
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Fault impedance type?
Usually fault impedances are resistive type. But is it possible to have a mix of resistive and reactive component in fault impedances? Looking at many simulation tools, they give the possibility to ...
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Does a grid-connected induction generator create phase difference between the grid voltage and generated current?
I saw an answer to another question that stated:
"An ordinary induction generator connected to a power grid will draw lagging reactive volt-amperes from the grid and supply real power to the grid....
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How does the electrical power from the output of a generator vary after a fault?
I know that after a sudden generation/load variation there is an imbalance between mechanical power and electrical power at the borders of generators which causes a frequency change according to the ...
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Mechanic and electric power after imbalance in power system?
After a power imbalance (for example a generator disconnection) in the electric grid, generation and consumption are not equal. This causes a dynamic transient in generators described by the Swing ...
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Is the power frequency characteristic of a network almost constant?
When a transient phenomenon happens in an electric power grid, the network reacts to this deviation with a power-frequency characteristic (MW/Hz). Reading the following paper ''Analysis and ...
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Self regulating effect of loads for frequency control
How does power absorption from loads depend on frequency? I know that during a frequency deviation in power grid, there are primary reserves which control the frequency, but I know there is also the ...
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Who gains money when domestic photovoltaic electricity is injected on the grid? [closed]
As an equity measure to ensure that everyone pays for the grid use, in multiple places we, the citizens/consumers, don't get refunded when we inject our excess photovoltaic production into the grid.
...
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How are primary reserves activated for frequency control?
How are primary reserves activated for primary frequency control? In particular I have the following doubts:
Is there a frequency threshold where each of them are automatically activated or they are ...
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Rated nominal power of generation with respect to load condition
In the electric power grid generation and consumption must be always the same. For sure the load change continuously in time, therefore an equal generation change must always correspond to the load ...
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what is the surplus-control of generation?
Reading the ''P1 – Policy 1: Load-Frequency Control and Performance'' document, published by UCTE in 2009 (it is available on internet for all) I noted that there are many contributions to Load-...
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Is the generator inside thermal power plants a synchronous type or asynchronous one? [closed]
Are thermal power plants connected to the electric power grid based on synchronous generation or asynchronous one? If a mix, which is the main one?
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nature of the load connected to the electric power grid
I know that loads can be modeled either as constant impedance or as fixed power P and Q. I also know that the majority of the loads are constant impedance type but I don't know exactly the percentage. ...
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Can loads absorb more power than needed/requested?
I was designing the governor of a generator, implementing in Digsilent Powerfactory a 1 bus grid like that in the picture.
The generator delivers 350 MW and the 3 loads withdraw respectively 25 MW, 25 ...