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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137 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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44 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
55 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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1answer
43 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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30 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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28 views

Can I use the ground wire of the grid with the power from my inverter?

In other terms : Can i connect ground wires 1 and 2 together ? EDIT : I'm in France, Grid is connected to a ground rod. System is 230v AC.
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1answer
22 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
24 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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14 views

Contactor utilization category

Is a contactor of utilization category AC-1 applicable to switching a whole single-family house (of say 65A, 30kW @ 230V) on or off? Since AC-1 means "Non-inductive or slightly inductive loads, ...
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25 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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12 views

How do I model a building as a load of a microgrid using Simscape?

I have to build a microgrid in Matlab, and I think the best approch is using Simscape, as part of a bigger project. The problem is that I don't know much of electrical engineering since I study ...
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41 views

How do I solve this power grid?

Here are a few things that I thought of or that I'm confused about. I think I am supposed to simplify the circuit itself to be more easier to work with. I was confused that there was no current or ...
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1answer
42 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
53 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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57 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
57 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 ...
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1answer
61 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
31 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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12 views

Real Electrical Grid Operation with OPF

So I spent some time reading Power System Analysis & Design by Duncan Glover, Overbye and Sarma and I have a question concerning real power systems operation. If we run optimal power flow once ...
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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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1answer
237 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
133 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
40 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
119 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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226 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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26 views

Why the Photovoltaic(PV) variations may cause shutdown in the main grid

If we assumed that PV generator is connected to the main grid, as the PV depends on solar irradiance it is considered to be a variable source. If the PV source can cause variations that could be ...
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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 ...
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1answer
64 views

Will a large amount of constant-power loads make an electrical grid unstable?

Over time, a larger proportion of electronics are constant-power loads, while they used to be constant-resistance. Will this lead to an unstable grid? If not, why not? Constant power loads at home ...
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520 views

Producers consumers balance in the grid

In a large distribution grid, it is said that consumers and producers must be in balance; what that means physically, in correct (not simplistic) mathematical formulation, is not clear: perfect ...
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1answer
33 views

IEEE test system accuracy and transmission line connections

In practice, do transmission lines ever directly connect two electrical generators to each other? Or is it more common for two generators to be connected indirectly through a substation? In the IEEE ...
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59 views

How is AC load distributed across on-site generation and the utility?

I’m trying to understand the physics behind AC load distribution when distributed on-site generation is installed and the load is also connected to the grid. In the diagram below, I have a building ...
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4answers
6k views

5 V home network

I'm planning on adding multiple IoT devices in my house, and I'm looking for an elegant solution to power them all. They'll all need 5 V, a small number of them (cameras) would draw up to 2 ...
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1answer
85 views

Cost of systems to connect a 6 MW wind turbine to the grid

Assumptions: The turbine is pretty close to an American (US) grid. National Grid will charge $50,000 to install isolation switches and remote control systems that let the device connect to the grid. ...
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2answers
152 views

Has there ever been a case of overvoltage in a power grid?

Every now and again we read about blackouts, where the voltage of the power grid drops and the infrastructure is paralyzed. But have there ever been cases where the power grid experienced a massive ...
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120 views

Where will the grid-tie power go if it's not connected to the grid? [duplicate]

What will happen to the extra power that the grid-tie inverter is producing if the demand is less than what the load needs? I have this planned system that I will be implementing soon. The good thing ...
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4k views

Why/when is AC-DC-AC conversion superior to direct AC-AC conversion?

I am currently studying wind power and the power electronics used for it. In wind power a generator is driven by wind, thus the resulting power is of widely varying frequency and amplitude. The power ...
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2answers
97 views

Current flow in step-up and step-down transformers of a power system

I have a question with respect to the current flow in step-up and step-down transformers. AC transformers work only when an alternating current flows through the primary so as to induce current in ...
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0answers
45 views

Interpretation of IEC 61000-3-6 (Assessment of emission limits for the connection of distorting installations to MV, HV and EHV power systems)

Based on the installation I want to calculate the acceptable current harmonics related to my installation. IEC 61000-3-6 says: For each customer only a fraction of the global emission limits GhMV+...
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4answers
489 views

Is there a minimum amount of electricity that can be fed back into the grid? [closed]

This is not fully related to electrical engineering, but I have been reading lately about Feed-in-Tariffs and solar energy production and I cannot find any information on the amount of energy that can ...
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4answers
161 views

Volume risk in an electricity market

I have been reading lately about electricity markets and I have stumbled upon the term "volume risk". Volume risk is often used to denote the phenomenon whereby electricity market participants ...
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4answers
3k views

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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1answer
155 views

The life of a high voltage line

In my neighbourhood, a 220 kiloVolt high voltage line is being renovated. It seems that they are replacing the cables, and they also may do some other maintenance. This, however, gave rise to some (...
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1answer
159 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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227 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 companies are sometimes forced to turn on a couple of jet engines in order to compensate for the loss, is ...
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1answer
87 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
25 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
60 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
46 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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2answers
161 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 ...