Questions tagged [power-engineering]

Power electrical engineering. Includes industrial electrical engineering (i.e. motors, switchboards), transmission and distribution (poles, wires, transformers, grids) and generation.

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How can I simulate the power consumption and production and see the behaviour in real time (in forms of graphs)? [closed]

My purpose is to create a kind of monitoring power system where I can see the power production from different sources, and add power consumption also. The thing I cannot understand in this simulation ...
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What does "CON LAY" mean when it comes to conductor stranding?

I am reading the book "Distribution System Modelling" by Kersting, and in the Appendix there is a Conductor data. Under stranding it says CON LAY for some conductors (like 250,000 AA). What ...
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Power factor of a synchronous based DER

I am working on a project including a synchronous based DER (2 Gens).I have a few question, I'll appreciate if you could help me. 1- I want to see what would be the typical control-mode setting of the ...
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Is there anything to limit LED output dimming 50% while the wall dimmer controls 50% to 0%?

We got a project for a client but our lights are too bright for the space, we still want to sell the the lights because we have extra inventory and need a way to dim the LED output to 25W instead of ...
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Where are power quality disturbance classifiers and detectors useful?

Power quality disturbance (PQD) classification and detections algorithms constitute a decent part of the literature in Electrical Engineering. Where are these classifiers and detectors useful? Grid ...
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Feasibility of 30MW DC transmission over 400m?

We have an electric motor final load of 10-30MW, in an isolated industrial location. The power source could be (Li-ion) battery packs, where each pack outputs 1500VDC, ~500A. Having 10-30 of these ...
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Sorting very different voltages and use them to charge batteries

I'm working on a project to produce electricity from a source that can produce sometimes negative, sometimes positive voltages, ranging from mV to kV depending on the situation, with very little ...
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why does voltage drop across a resistor

I have seen the explanations about the energy lost in from of heat, but that energy comes from the net reduction of kinetic energy of the electrons (reduction of current). More over voltage is a ...
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3 answers
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How is frequency measured in a power grid?

I know that voltage and current are measured with voltmeter and ammeter, but how is the frequenc measured in power grid applications? I know that a phase locked loop (PLL) can be used, but is this ...
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Duty cycle in flyback transformers

I have a small doubt. If the flyback transformer is designed to vary duty cycle from 5-50% and obtains an output voltage of 5 to 100 V. Here, can we increase the duty cycle beyond 50% (70-80%) as to ...
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How do I connect a three phase transformer with three center taps?

I have a three phase step down transformer with three center taps like shown below: How can I connect it to get the 90 V three phase lines or the 45 V three phase lines at a time for circuits that ...
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How to (theoretically) capture 59 megajoules of power in 5 seconds to store like a battery for a month? [closed]

On Dec 21, 2021 EUROfusion Scientists in Culham, UK produced 59 megajoules in 5 sustained seconds from their nuclear fusion experiment. What theoretically would be required to capture that energy and ...
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Deriving power formulas for transmission lines

I'm trying to derive formulas for active power (\$P_s\$) and reactive power (\$Q_s\$) at the sending end of a transmission line shown below: Where: \$E_s\$ and \$E_r\$ are voltage magnitudes \$X\$ is ...
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Semiconductor chip shortage [closed]

Does anyone have an answer why do chip distributors have almost virtually zero stocks? Is there a shortage?
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Pilot light, logic and Opto issues

First time poster, long time lurker. I’m an electrician to start with, so excuse my lack off EE expertise. Trained in the elevator industry but now float around a few industries. I’m putting together ...
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Calculating the new per unit impedance of a transmission line

The per unit impedance of 98 km of 412 kV transmission line is (0.768 + 4.823i) x 10^-3 to bases of rated voltage and 115 MVA. Calculate the magnitude of the per unit impedance when the apparent power ...
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Understanding electric power charging a battery

Let's say I have a machine that produces 1 joule per second. I then use it to charge a battery for 1 hour. The questions are: Would the battery then have 3600 joules stored in it? If I was to plug a ...
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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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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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What is the difference between applied voltage and induced voltage at primary side of transformer specifically?

I am not able to understand difference between applied voltage and induced voltage. Whenever voltage is applied at primary side of transformer there will be primary current producing flux using ...
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1 answer
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How power system handle unbalanced load?

how a delta connected primary winding of three phase distribution transformer tackle unbalanced load of three phase 4 wire unbalanced load(unbalanced load is quite common due to supply of single ...
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3 answers
132 views

Short circuit current calculation

** I DON'T WANT THE SOLUTION ** The question is: A three phase 50MVA, 4,160V generator with a reactance of 7.9% is connected to a three phase 4,160V/480V step down transformer rated for 1.5MVA with an ...
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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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Fault Ride Through requirements for wind turbines

First a short introduction: (the question is below the first image). The capability of fault ride-through of wind turbines is the most important requirement related to national grid codes. Based on ...
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Transformer load

I have 50 kVA delta-wye transformer with 3 single phases secondary (line-neutral) delivered to 3 houses, So if one of the 3 houses drown more power would that affect another 2 houses, or each phase ...
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2 votes
1 answer
273 views

Sequence Impedance/Zero Sequence Impedance of lines

I am trying to calculate the Sequence Impedance/Zero Sequence Impedance of couple of lines, but Im not sure if the calculation are right, and besides there are some tricky things on the data provided. ...
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What does pole rating and bipole rating mean for HVDC transmission cables?

I was just reading on HVDC underground cables. And according to the picture below, as they were listing out the parameters of the cables used, they mentioned pole ratings and bipole ratings. How are ...
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Arlec grid connect bulb and power points DC convert smart WiFi hack

These devices works off 240V AC. I was looking to convert them to run off DC and keep the grid connect app function. https://www.bunnings.com.au/arlec-9w-950lm-4000k-grid-connect-bc-smart-...
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3 votes
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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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2 simultaneous voltages from a transformer

I need a step down transformer that can give me 2 voltages simultaneously. Primary will be 380vac and secondaries will need to be 24 vac and 12 vac. Instead of using 2 transformers, I would like to ...
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3 answers
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How to tap the full power of a 3-phase circuit

I know I can power my high voltage single phase AC or DC circuit by tapping either one of the L-1 to L-3 legs and return a neutral to the neutral line however I'll only get as much power from one 60Hz ...
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How do appliances prefer to use my solar power from a grid-tie inverter over the power from the grid?

I have a grid-connected solar inverter. In the swtich board the incoming wire from the street, the incoming wire from the inverter and the outgoing wire to the loads in my house are all connected ...
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3 votes
1 answer
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How does a grid-tie solar power inverter know when the mains power has failed?

Solar power inverters that send excess solar power back to the grid are (usually) required to shut down if the grid power fails. (This is to protect people working on the power lines.) The inverter ...
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How close can a circuit board be to an overhead power line without being effected by EMI?

I am researching a technology that will need to put some circuitry near a power line used on the electric grid and I was trying to determine how close can I get to the power lines with my circuit ...
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2 answers
101 views

Can switching between two unsynchronized sources cause problems for an average office building?

We have a 100kW 3Φ 208V generator and ATS operating in North America. The system as installed does not allow for a test where the load can be placed on generated power when utility is available. We ...
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Confusion in modelling of total loop inductance of a rectangular loop

I was reading an article about partial and total loop inductances from this site and in a section where for calculation of total inductance of a rectangular loop is given as: In each portion of the ...
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NEPLAN Load Flow Analysis with 1-day measurement

currently I am working on a project to identify energy loses in an electrical network. I am using NEPLAN 10, and already build a small system and implemented measurements. As soon as start the ...
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-1 votes
3 answers
121 views

How does electricity from a 3 phase 4 wire 480Y/277v EV meter differ from a standard 120v wall outlet?

I am wondering what the difference is the electricity that comes out of the switchboard/utility meter that is designed to be a separate meter to measure a customer's use of power that only goes to an ...
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4 votes
4 answers
187 views

what role does transmission line termination take in long distance power lines?

Does transmission line theory and transmission line termination take any significance when dealing with long high-voltage power lines? Do power companies terminate their power lines to avoid ...
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0 votes
3 answers
228 views

Is there a circuit element which dissipates energy but does not act as a resistor? [closed]

I know this sounds a bit weird, but is there a circuit elements which dissipates energy if a current flows through it but is not a resistor? In other words, is there an energy sink which does not ...
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Can electronic devices be installed on the pillar of UHV towers such as 345kV?

Can electronic devices be installed on the pillar of UHV towers such as 345 kV? Because I have an idea to install a remote automatic control electronic device on the tower to control the rotation and ...
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Inductance of composite conductor

Why L is calculated using average value and not by the formula 1/L = 1/L1 + 1/L2 + ...
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3 votes
2 answers
169 views

Delta-Wye transformer differential protection during external line to line faults [closed]

During these kind of line to line faults current flows in the faulted phases of the secondary and all phases of the primary as it is shown in the image. So now the currents in phase A are not equal to ...
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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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Selecting the correct wire for very short power transmission

Looking for the thinnest wire for very short distance power transmission. Supply is 5V, 10A. Ambient temperature is 35C. There are 5 consuming elements, each consuming 10W. The elements are linked ...
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What happens when a multi-fuel generator reaches capacity on LPG or NG?

I have a multi-fuel generator rated for 7.5KW on gasoline, 5.5KW on natural gas. It has a 30A circuit breaker that will trip if demand exceeds capacity on gasoline I would like to understand in some ...
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How much information would a network protector need to determine if a backfeed is due to feeder failure or power export?

Many downtown or otherwise densely built-up areas, as well as some major metropoles (much of NYC, most notably), use secondary network electrical service to maximize service reliability and keep ...
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-1 votes
2 answers
69 views

frequency for a 90° phase shift [closed]

It seems an easy question but I just can find out how I'm supposed to do it: what frequency is needed so that Vin and Vout have a 90° phase shift. (picture below just as a matter of an example circuit)...
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17 votes
4 answers
8k 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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Offgrid backup AC power option

I’ve been building an off grid home for a few years - recently moved in full time. Living in VT, with limited solar, we depend on a Honda EM6500SX 240v generator to occasionally recharge 20 batteries ...
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