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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Is it practically possible to transfer electrical power around the world by wires?

Assume that we installed plenty of solar cells in all continents; mainly in Asia, Africa and America. Can we transfer the electrical power harvested from them around the world through wires, so that ...
1 vote
2 answers
57 views

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 ...
-1 votes
1 answer
35 views

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 ...
0 votes
0 answers
19 views

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 ...
1 vote
3 answers
5k views

What are the effects of trimming the diameter of a wire down to half its gauge?

I have a three-phase, 4 AWG 259/28 stranded power transmission cable (3 conductors total) running ~200m into a slip ring. The only way to connect to the slip ring is by using its 8 AWG pig tails. ...
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 ...
1 vote
3 answers
1k views

Grid is capacitive in the evening

what does this term mean? "the grid in the evening is capacitive"? I work at a company and we are working on integrating a battery storage system on a utility scale for peak shaving of solar. When we ...
-1 votes
1 answer
57 views

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 ...
22 votes
8 answers
67k views

What happens to excess energy fed into the power grid?

The closest question to this is Linear useage of excess power generation. I'm no engineer so I may not be able to phrase this correctly and would appreciate an answer which assumes minimal ...
0 votes
0 answers
18 views

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 ...
3 votes
5 answers
398 views

What happens to a high power inductive motor if you decrease the RPM to half the rated in terms of current, torque and heating?

and what is minimum possible RPM ratio for a high power motor
-1 votes
2 answers
91 views

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 ...
0 votes
0 answers
38 views

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 ...
0 votes
2 answers
125 views

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 ...
2 votes
3 answers
141 views

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 ...
1 vote
1 answer
80 views

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 ...
1 vote
2 answers
90 views

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 ...
1 vote
2 answers
122 views

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 ...
0 votes
1 answer
208 views

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-...
0 votes
1 answer
89 views

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 ...
1 vote
1 answer
86 views

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 ...
15 votes
4 answers
68k views

Why does a delta/wye transformer make 30 degrees phase shift ?

I'v heard that a delta/delta or Wye/Wye transformers do not make any phase shift. In delta/wye or wye/delta transformers, There is a 30 degrees phase shift between the primary and secondary coils. So, ...
0 votes
1 answer
219 views

Capacitance of short length transmission lines

I would like to simulate a short length transmission line in MATLAB/Simulink. In the library, there is a block that simulates a transmission line. The parameters that are required are the resistance R,...
2 votes
1 answer
281 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. ...
6 votes
2 answers
497 views

Transmitting VCC and GND signals for use with RS-485

The specific question I want to ask is whether I can transmit VCC(5VDC) and GND power signals for powering the destination circuit (in an RS-485 arrangement) or not. The power lines will be grouped ...
0 votes
2 answers
3k views

Designing a BLDC generator

I am trying to design a brushless DC generator system for portable use of charging batteries and if suitable possible hybrid power system of an aircraft. The "BLDC" motor/generator will be connected ...
-4 votes
1 answer
81 views

Semiconductor chip shortage [closed]

Does anyone have an answer why do chip distributors have almost virtually zero stocks? Is there a shortage?
-1 votes
2 answers
76 views

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 ...
2 votes
1 answer
2k views

What types of bus couplers exist?

There are various types of bus couplers (for double bus system, single section bus system, etc.). I know that bus coupler between two busbars is called cross bus coupler. How are other bus couplers ...
2 votes
1 answer
347 views

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 ...
0 votes
1 answer
71 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 ...
0 votes
1 answer
70 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 ...
3 votes
2 answers
329 views

What are these parallel connected lines meant for?

During my walk today, I noticed these small parallel connected lines. What purpose do they serve?
0 votes
2 answers
292 views

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 ...
-1 votes
1 answer
94 views

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 ...
0 votes
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 ...
1 vote
4 answers
381 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 ...
3 votes
1 answer
75 views

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 ...
-5 votes
1 answer
1k views

Do fiber optics make any noise/sound that can be heard by the human ear?

In regards to, "...the noise sources in a fiber optic link include noise from the RF amplifiers in the transmitter, the laser diode, the photodiode and RF amplifiers in the receiver. Of which laser ...
0 votes
0 answers
64 views

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 ...
0 votes
3 answers
2k views

What does "reconductor" or "reconductoring" refer to?

This is a term that I seem to remember hearing in reference to electric transmission. I'm pretty sure it has something to do with upgrading a set of transmission lines to carry more current, but I'm ...
0 votes
0 answers
40 views

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 ...
3 votes
1 answer
88 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 ...
0 votes
1 answer
67 views

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 ...
0 votes
3 answers
75 views

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 ...
0 votes
3 answers
91 views

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 ...
3 votes
1 answer
120 views

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 ...
-1 votes
2 answers
6k views

Primary and secondary substation equipment

There are many devices that can be found in the substation. One of the categorizations for substation is between primary and secondary substation equipment. Which device types belong to each ...
0 votes
2 answers
167 views

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 ...
0 votes
0 answers
44 views

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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