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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questions
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Problem in the current waveform during PV power injection to the electrical network
When I connect my photovoltaic system to the electrical grid through a dSPACE DS1104 testbench, the inverter output current becomes as shown in the attached figure.
Before connecting and during the ...
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4answers
176 views
How does a power plant's increased output translate to the Volts, Amps and Watts on the power lines?
In the context of a power plant, that wants to output more electricity.
If the formula for Watts is V*A=W, does Voltage or Current get increased to supply more ...
3
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1answer
68 views
Why does reactive power injection mitigate sagging grid voltage?
I understand that reactive power injection can be used by generators to support the grid voltage when sagging, but I’ve never understood why this works. I thought it could be charging transmission ...
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1answer
90 views
Why a voltage drop at the busbar's generator?
I was testing the effects of distributed generators on our grid. To do so, I inserted a PV generator of 90 MW PURELY ACTIVE (power factor = 1) as in the picture. I performed a quasi-dynamic simulation,...
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1answer
62 views
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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1answer
68 views
How can grid frequency dropping lead to grid failure [closed]
From what I understand, frequency variation indicates generation-load imbalance. In particular, when frequency decreases the load demand is greater than generation.
Wouldn't this just lead to the ...
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2answers
228 views
How is a line commutated inverter different from a grid-following inverter?
The U.S. Department of Energy provides this definition of a line commutated inverter:
An inverter that is tied to a power grid or line. The commutation of power (conversion from direct current to ...
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1answer
30 views
How do generation schedules / load schedules work on a power grid?
I've noticed that some generating stations have "generation schedules" and similar schedules also exist for load distribution stations. They usually have a MW amount telemetered to the ISO (...
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4answers
353 views
Electrical phase in a power grid and power transmission
I'm very new to the study of power grids and I'm having some trouble understanding some very basic concepts.
I have been looking at the problem of synchronisation on power grids and I'm not quite sure ...
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1answer
45 views
How to calculate energy added to grid using active and reactive power?
I have recently installed solar system that adds energy to the grid. My utility company has installed bi-directional meter at my place to record energy consumed as well as energy added to the grid.
...
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0answers
53 views
Battery cost LCOE and carbon emission by hourly. Validation of calculation approach
I am compiling a report and trying to validate my understanding of using power correctly to multiply with constants like price and emission in kg weight. Please point out if the approach below is ...
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1answer
71 views
How does the grid handle small deviations of power consumption when most of load is regulated?
This is a continuation of this question. Suppose we have a grid which distributes say one gigawatt total power and all this power is perfectly fully consumed by electrical devices.
However all ...
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2answers
175 views
Why does it take such a long time to build a new power grid transformer?
From time to time, when people are discussing the consequences of power outages, like the ones from the Texas winter storm or a hypothetical catastrophic space weather event (Carrington event scale), ...
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1answer
111 views
How can wind turbine be used to frequency control in a grid?
I was listening to an interview (sorry don't have the source) from the Mexican's minister of energy, where he mentioned 'Wind turbines are useful even when the wind is not blowing because they can be ...
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0answers
42 views
Electronic earth
I just want to know basic information about it and why it is not to be connected with main ring of electrical plant.
If there are any references for it i will be grateful.
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1answer
226 views
Why can generators be damaged by series capacitors (SSR)?
Specifically I am talking about generation that uses steam to generate turbo spin (steam cycle) like nuclear or natural gas plants. I have been learning about Subsynchronous Resonance (SSR), which is ...
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103 views
Calculating the line-to-neutral voltage of a generator
A three-phase generator is connected to a strong grid with
line-to-line voltage 14 kV and frequency 50 Hz. The generator is rated
at 15 kV and 180 kVA. The resistance in the windings is 2 Ohm/phase
...
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1answer
360 views
How to use the rate of change of frequency equation to calculate frequency drop in a grid based on lost generation
My question involves calculating the frequency drop in a power grid when a load is lost. The closest question I have found to mine is, Change in frequency in a grid that has lost generation?
Based on ...
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4answers
6k views
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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2answers
297 views
Effects of low voltage on power grids?
I understand that if load is suddenly ramped up on a power grid:
A sudden increase in current is caused by adding these parallel loads to the circuit.
The current increase thus increases the torque ...
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votes
3answers
349 views
What happens with the power grid if nobody uses electricity?
How much electricity does consume electric system by itself? Just to have an option at any moment to plug in anything at socket at home and turn it on. There are huge power plants to convert high ...
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7answers
7k views
Why do power grids tend to operate at low frequencies like 60 Hz and 50 Hz?
I understand that a two-pole AC generator has to rotate at 3600 rpm (60 Hz USA) in order to maintain a 60 Hz frequency and higher frequencies would require these generators to spin even faster which ...
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3answers
219 views
Why can't circuit breakers close across a large phase angle difference?
In power systems I understand that breakers have mechanisms preventing their closing if they detect the phase angle (and voltage) across them to be too large. This is usually called a 'sync check'. ...
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1answer
37 views
Voltage value after generators in the power grid
What is the value of the voltage before the step-up transformers and right after the generators in the power grid?
I mean the generators connected to the high voltage grid through step-up transformers....
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3answers
2k views
What happens to excess electricity generated going in to a grid?
How is excess electricity generated dissipated? I know that the grid is balanced, etc. But given that there will be momentary over-generation at some point over the whole grid where does any excess ...
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0answers
18 views
Can we control the data sending by Phasor Measurement Unit (PMU)?
Since PMU send the data after sampling the data to the PDC. Can we design any scheme so that PMU send the data to PDC only when I want? That means to reduced the communication bandwidth can we design ...
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1answer
104 views
Why are current transformers used in power stations?
I read that surge arresters in power stations suppress the high incoming voltage and the output passes on to the current transformer.
If surge arrester already reduced the voltage then why is the ...
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2answers
72 views
At what distance(s), approximately, are high-voltage DC (HVDC) power lines more efficient than AC lines?
I hope this is not a duplicate, because I am sure other people have the same question...
And could someone explain the reasons why?
N.B. From the 'scienceabc' website linked to below:
Despite being ...
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votes
1answer
108 views
Generator inertia
I am little bit confused with the idea of generator inertia for interconnected system. Below you can find my small questions.
What is the meaning of 200 GVAs as a metric of inertia?
If there is no ...
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4answers
228 views
What stops AC from my UPS leaking into the grid?
In many parts of the world (where power cuts are relatively frequent), we use "Uninterrupted Power Supply" (or UPS), which is an inverter connected to one fraction of the household circuit (...
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3answers
377 views
What is a node in a Power Grid
I have heard the term Node in the Power Grid or Smart Grid, what does this node compose of? Is it a group of houses connected to the same substation?
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1answer
60 views
How do electric utilities determine the Load Demand on the network?
Provided that electric utilities are tasked with ensuring that the load demand is always met, how do these utilities determine load demand to be met in the first place in real time rather than using ...
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vote
1answer
68 views
What is the relationship between Power Generated in the grid and Voltage delivered?
I am trying to understand how the grid works. Lets say we have some gas turbines, where we have a combination of air and fuel being used to turn turbine blades which in turn drives a generator to ...
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0answers
40 views
UPS in front of an ATS for generator protection
At the countryside house there is this setup:
And I am trying to protect the generator and house load from brief ~ 1s power outages like so:
It works fine in normal conditions. Trouble is when I ...
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1answer
25 views
Delta Servo Drive 220V/400V Series
ASDA-A2 Delta Servo Drives including two types: 220V and 400V series that it seems the difference is input voltage of the Servo Derive. but i doubt 220VAC or 400VAC is line to line voltage or line to ...
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1answer
33 views
Wall Voltage in 3Phase
I have a relatively simple question on the grid voltage. When we say the voltage from the wall is 220 Vrms is that the line-line voltage or is that the phase voltage. ie are the two output lines from ...
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0answers
27 views
Currents injected in the grid, connecting a wind turbine
I'm studying the connection to the grid of a wind turbine through a three-phase inverter.
Now I understand that , in normal operating conditions, in the connection to the grid, the reference for id ...
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1answer
54 views
How do I design a microgrid using Simulink?
I have to do a project in which I have to model a microgrid which is controlled by using reinforcement learning techniques.
In doing so I have a problem, because I study control systems and I don't ...
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1answer
69 views
Why makes ground "ground"? [duplicate]
We all know that birds don't get electrocuted while standing on a single power line, but if the bird touched the ground while holding the power line, it will die instantly.
One thing that riddles me ...
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2answers
64 views
What is the effect on power grid when utilization goes down some threshold?
Today (April 5th, 2020) at 9:00 PM IST, people across India are expected to switch off lights for 9 minutes.
This has apparently raised concerns that there would be problems to the power-grid, due ...
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1answer
72 views
Impact on grid if entire country turns off all electrical appliances within few seconds and then turns them on within few seconds
This is not a hypothetical question but a real one. My country (India) will be turning off all their lights at 9 PM local time on 5th April. They will keep it off for 10 minutes and then turn it back ...
3
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1answer
116 views
Can my solar inverter be significantly driving UP my power consumption or my meter counting excessive production as usage?
I've had a 1.5KWh PV solar system for 3 months now and as any new user I've been monitoring the power generation closely. I've wanted to correlate the power generation to my power usage so I've ...
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1answer
88 views
How to estimate active-power transmission capacity based on voltage levels and line lengths
I know voltage levels and line lengths of high-voltage transmission lines and I am looking for a rough estimation of the maximum active-power transmission capacity during normal operation. By normal ...
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3answers
5k views
How have my neighbours’ appliances been damaged?
In the aftermath of the recent storms in the UK, one of my neighbours reported a flash and loud bang from his local transformer station, and the power briefly cut out.
After that, several households ...
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votes
1answer
680 views
What happens to the electrical grid when I turn on a heavy load?
I'm trying to understand exactly how an electrical grid works, and I'm having one simple question that is challenging me. What happens when a new load appears on the grid? I know in practice that any ...
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2answers
149 views
Why would doing the "outlet challenge" cause notable damage to outlet and wiring?
WARNING!!! WHAT "PRANKERS" IN THE VIDEO DO IS MOST LIKELY VERY DANGEROUS AND MAY CAUSE DEATH, INJURY, FIRE OR OTHER DAMAGES AND IT SHOULD NOT BE TRIED IN ANY ELECTRICAL SETUPS WHICH ARE NOT DESIGNED ...
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1answer
99 views
Quantify Grid Stiffness
Being the stiffness of the grid its capability of maintaining the voltage constant despite small variations on load. Whereas, a weak grid would be easily affected by load variation and the voltage ...
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1answer
403 views
Why do large power stations' generators rotate at ≥ 1800 RPM?
Some time ago, over some beers with a fellow EE who's much more experienced than me, we were discussing the unique challenges present in utility-scale power generators, like the ones in nuclear power ...
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0answers
401 views
What will happen if the prime mover driving synchronous machine is accidentally disconnected?
What happens to a synchronous machine connected to an infinite grid, acting as a generator, when its prime mover fails i.e. when mechanical input at the shaft reduces to 0?
I'm assuming that the ...
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votes
6answers
13k views
What is the speed of "electricity"?
In a distribution grid, what is the speed of
energy
signal
Is it strictly the same?
And how is synchronisation achieved? Is an electric grid essentially an orchestra where everyone is the chief ...
