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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11 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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100 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
126 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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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
95 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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120 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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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
59 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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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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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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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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84 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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25 views

Impact of Interconnection of One Energy Generating Plant At Another Generator Plant's Generator Bus Bar(PV Bus Bar)

As the scheme attached below, we're interconnecting 5.5 MW of generated power of upstream project(Around 2 km Away from the Interconnecting Switchyard) to the Generator Bus Bar(PV Bus Bar) on 11 kV ...
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2answers
149 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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82 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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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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52 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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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
487 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
131 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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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
153 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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63 views

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
110 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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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
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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
71 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
48 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
45 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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135 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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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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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
60 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
137 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
76 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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69 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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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
438 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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101 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
81 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
87 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
275 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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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
79 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 ...