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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4 votes
2 answers
123 views

How do power grid operators regulate the power flowing through their networks?

My question: How do grid and transmission line operators regulate the amount of power flowing in their networks, both to utilize the network optimally and to enact delivery policies like those in the ...
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2 votes
3 answers
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The voltage created in the transformer

The voltage generated in the transformer must be due to the change in the flux in the coils, but if the voltage is DC, why is no voltage induced? Of course, we know that voltage is created by the ...
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2 votes
1 answer
90 views

Cost of pin insulators

H. Cotton's Transmission and Distribution of Electrical Energy states that the cost of pin insulators increases exponentially with voltage. Why is this, and why isn't it linear?
4 votes
3 answers
202 views

How many winding turns in a HV power transformer?

I'm creating a simplified 2D model of 3 three-winding 132/22 kV, 40 MVA transformers that I'll use to calculate the magnetic field surrounding them. Now, the turn ratio is of course 132/22, but is ...
0 votes
2 answers
67 views

Cutting a 1500 W heating coil into two halves and using one half for a project

I have a heating coil (Nichrome coil) of 1500 W working at 230 V. I need to cut it into two halves and use one half for my requirement at 230 V without burning my coil. I know that if I use half the ...
1 vote
2 answers
44 views

Inverse temporal power-law increase of DC voltage under the application of constant DC current

Is there any material in which the DC voltage follows an inverse temporal power-law increase, under the action of a constant DC current? This implies a situation in which a constant current, I, is the ...
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-2 votes
1 answer
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Why aren't stranded wires used more widely if conductivity is improved and price is reduced?

Why aren't stranded copper coated aluminum cables (CCA) widely used outside a small niche of speaker wires or 12 VDC applications? According to this post the issue is with the insulation jacket which ...
1 vote
4 answers
119 views

Matching generation and consumption in renewables

To balance power generation and consumption, traditional power plants such as thermal and hydro have governors that regulate the steam/water that flows into the turbine. The energy that renewables ...
0 votes
1 answer
49 views

Grid Voltage Ride Through using PSSE

I am trying to simulate a low voltage ride through (LVRT) lagging case (Qgenerator = max). The inverter seems to be going to momentary cessation, and although the output power at the inverter ...
-1 votes
2 answers
108 views

Transmission Line model [closed]

Can some one explain me why exactly classical circuit theory fails to account for the wave nature of EM fields and how the transmission line model accounts for it better
0 votes
1 answer
47 views

RMS voltage between two arbitrarily phased AC lines

As part of a thought experiment to determine the barriers to electrification of a street running railway using 25kVAC single phase overhead line, I found myself consulting the clearance rules in the ...
0 votes
1 answer
60 views

Increasing Power Line Voltage to Reduce Current?

I need to deliver 5V, 1A (5W) of power to a load that's 5+ meters away from the power source, however I'm keen to use small-ish wires and connectors, which I know will result in volt drops through the ...
13 votes
2 answers
1k views

What is the reason for these utility poles with a 6-sided hole in the middle for conductors

What would be the technical (Electrical, structural, safety) reasons for a utility pole like those shown below? This picture was taken in Arkansas and is what I assume to be 3-phase power. Note how in ...
0 votes
1 answer
61 views

What happens on a DC-DC grid connection after a perturbation in the synchronous grid?

Consider the Continental Europe synchronous grid. This power system has some DC-DC connections with other countries (for example one with Great-Britain). Suppose now there is a sudden big outage ...
0 votes
1 answer
66 views

A question regarding Reactive power

Why does the production of reactive power not require extra fuel unlike active/real power?
1 vote
2 answers
64 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 ...
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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 ...
0 votes
1 answer
67 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 ...
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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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2 answers
96 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 ...
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0 answers
40 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
170 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
210 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
2 answers
175 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 ...
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1 vote
2 answers
146 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
99 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 ...
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1 vote
1 answer
139 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 ...
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1 answer
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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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2 answers
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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 ...
2 votes
1 answer
279 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 ...
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2 votes
1 answer
352 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
80 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 ...
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1 answer
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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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0 votes
2 answers
543 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
223 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
188 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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1 vote
4 answers
482 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 ...
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3 votes
1 answer
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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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0 answers
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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 ...
2 votes
1 answer
469 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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1 answer
298 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-...
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3 votes
1 answer
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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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1 answer
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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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0 votes
3 answers
96 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 ...
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1 vote
3 answers
142 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 ...
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3 votes
1 answer
329 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 ...
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0 answers
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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 ...
0 votes
2 answers
132 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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