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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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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1answer
165 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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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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203 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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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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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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104 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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43 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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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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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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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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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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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
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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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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1answer
37 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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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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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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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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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
58 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
160 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
88 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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1answer
81 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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1answer
36 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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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 ...