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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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What is the result when THD V is maintained below 1.5 [on hold]

I am working in a project related to smart grid and I was getting value of THD V( Total Harmonic distortion in voltage) in power analyser below 1.5% what will be the order of harmonics(3rd or 5th or ...
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1answer
42 views

How much power can transit through a power line linking generation and load?

First things first I am not an electrical engineer at all so please bear that in mind when you reply/comment. I am looking at the following problem, I have a power line which connects a windfarm to a ...
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0answers
38 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
44 views

Assemble Peltier Cooler to Li-poly Rc Battery

I have procured a thermoelectric cooler (TEC, this one) and my purpose of the TEC is to produce current for the Li-poly RC battery to increase its battery life. The Li-poly RC battery has 7.4V stated ...
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0answers
20 views

Startup and auxiliary/station transformer power parallel to bus

This question is in regard to switchyard/electrical distribution operations in a utility power plant. During a startup, the electric distribution system is lined up so that the startup transformers ...
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2answers
83 views

What are the practical differences between AC and DC transmission?

I have a long (2m) but thick wire between transformer-based power supply and low frequency power amplifier. Know your best advice ahead, but no, I cant get rid of it. I can put it in two ...
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1answer
34 views

What is the effect of very small AC frequency deviations from the grid on invertors and transformers for normal comsumer objects?

What additional wear or inefficiencies are there from inverting a AC signal to DC from say, 59.99 hertz instead of 60.00 hertz? And is there additional wear on transformers? How do small deviations ...
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1answer
41 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,...
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1answer
67 views

How do you close a switch on a high-voltage network?

This is something I've been curious about for a long time. Let's say you're a utility trying to connect two segments of a distribution grid. Both segments will have about the same frequency, because ...
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2answers
119 views

Why maximum power transfer condition is suitable for communication system but not for transmission of electricity?

A fundamental concept that i have learned from basic electrical circuit study is to receive maximum power by a load of resistance RL from a source the necessary ...
2
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1answer
137 views

DC-DC step down 12V to 5V source versus straight 5V source

Here is the scenario: I have a project needing 3 supply powers: 3.3V to run the microcontroller (max 100mA) 5V to run a bunch of adressable LEDs (max 8A, the most current intensive) 12V to supply op ...
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1answer
99 views

How fast do power plants need to respond to demand?

I've heard the layman's description of electrical grid response time before - it usually contains the word "instant" or "real-time". But I'm interested in the actual response times of the various ...
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3answers
93 views

Chimp climbing wires not electrocuted? [closed]

Reference video: https://www.youtube.com/watch?v=U5-Fy4ULdPg The chimp is climbing both wires out of phase (i would have to assume, it is in Japan), do the power lines have to be closed for the chimp ...
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1answer
115 views

How many horsepower does an alternator take from an engine at different speeds? [closed]

I want to know how much horsepower the engine deliver to the alternator at idle rpm,normal rpm and maximum rpm
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1answer
63 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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1answer
78 views

How to plot input reflection coefficient in dB scale using Matlab

So I have a problem that asks to plot the input reflection coefficient of a transformer in dB scale between 0.5 GHz and 4 GHz using Matlab. Here is the code I have thus far, it is plotting in ...
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1answer
81 views

What is the typical voltage of power distribution in rural North America?

I mean the electrical utility power that connects to the transformer outside of the home or other buildings. i.e. what is the primary winding voltage of the transformer having 220 VAC center-tap ...
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1answer
93 views

How is power out one side of 220 only - Problem is with incoming 3-phase. But how?

[EDIT] Can someone who understands what I wrote explain this? [EDIT 2] Sorry I didn't say I'm in the USA, the power is 110/220vac 60Hz. The input to the main power transformer is 3-phase, underground,...
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0answers
77 views

Use of 3 phase transformers which are ∆-Y connected and Y-∆ connected

Different literatures say different things regarding ∆-Y and Y-∆ 3 phase transformer connection... Some say that ∆-Y is used for step down and Y-∆ is used for step up while others say just the ...
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1answer
352 views

Why is a short circuit in the secondary winding of a transformer reflected on the primary side?

I was reading this answer and I would like to understand why if the secondary is short circuited the primary winding will also reflect the short circuit despite the fact that they are isolated. Would ...
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2answers
55 views

Why does a End-Of-Line Voltage Drop Calc yield a different result than a Point-To-Point Calculation?

I can't grasp the concept on why these two different voltage drop calculations yield different results. They should both arrive at the same answer. In our intro EE classes when we were doing any ...
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1answer
36 views

Does a supergrid approach confront with distributed generation?

I have heard many times about supergrids and distributed generations (small scales generation connected close to the loads). In a supergrid scenario, a efficient and clean production of electricity (...
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1answer
171 views

Connecting a 48 V battery to a grid tie inverter

I am working on a grid tied wind system project. I am planning to use a battery in the system which will be the source to the grid-tie inverter. Also the battery will be used only as a source to the ...
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3answers
5k views

Why does power dip during a lightning storm?

If lightning were to strike power lines, wouldn't you expect it to increase the power, and hence your room lights get brighter? Why do they go dim for 1 second at a time?
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2answers
57 views

Regarding Power Market demand and supply

As I have read, that power supply should be equal to demand. As it can't be stored .So basically this means power is generated in real time. Consider an area where power comes from a Substation A, ...
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3answers
551 views

Process for Making a Flyback Transformer

I am looking to make my own flyback transformer that can put out a DC voltage from 0 to -40 kV DC and a power of 400 watts, as most commercial flybacks do not go up to the specified power and ...
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2answers
68 views

Engineering approach to choosing a motor, voltage and gears

I am working on a project to automate the opening and closing of my venetian blinds at home, by attaching a motor with an H-bridge to them. I started with a practical trial and error approach to it. ...
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2answers
501 views

Capacitor and inductor working principle

I want to know that there is opposition mechanism of current in inductor say back emf than what is opposition mechanism of voltage in capacitor ??? And also want to know that when inductor suddenly ...
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2answers
63 views

Controlling electrical flow from generator

I'm working with a factory which has a backup generator which is used during grid instabilities or whenever the factory must disconnect from the grid for maintenance. In these cases, the generator is ...
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6answers
567 views

Why am I getting shocked from “hot” line and touching “ground” (Earth)

So I live in an EU country and don't have Earth grounding for my house. Still I am getting shocked when touching "hot" line (220VAC) and standing on "ground" (Earth). How is this possible? From my ...
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2answers
94 views

How is the amount of outgoing power controlled in a grid tie inverter?

I'm trying to figure out how grid tie inverters work on a basic level. From what I understand, the inverter would have to monitor the grid wave create its own wave exactly like the grid make it a ...
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1answer
153 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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2answers
908 views

How is it possible to use a phase as a return path?

On the 3 phase system, it is possible to supply a 380V load using 2 phases, say L1 and L2. I understand that the phases alternate and that one phase acts as a return path for another, but this doesn't ...
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3answers
59 views

What could be the transmission loss per metre of using DC current for a low voltage solar system?

I think that it shouldn't be much but I wanted to get a ballpark numerical figure. We've installed a 2kW solar power unit at our home, which is installed on our rooftop. To convert the DC current ...
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1answer
41 views

State estimation in power system [closed]

Regarding state estimation in electrical power grid, does the voltage phasor magnitude at each bus(P-Q bus and P-V bus) considered as a static state variable or a dynamic state? I am a little bit ...
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1answer
86 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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0answers
25 views

Power Outages and Surges

I live in South Africa where we experience frequent power outages due to so-called "loadshedding". With this, there have been numerous cases of damage to appliances due to surges, usually when power ...
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1answer
79 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 ...
2
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1answer
78 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
56 views

What are the methods to measure distribution transformer vibration in 0.5g range?

It may seem obvious to use widely available analog devices MEME accelerometer for measurement in range of 0.5g. I did thorough study on this and found out that MEMS sensors either doesn't work or ...
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0answers
34 views

How can active power reserves in a meshed AC and meshed DC Grid contribute to the system operation?

I need your advice about my question, my question is about transmission system. I want to know - How can active power reserves in a meshed AC and meshed DC Grid contribute to the system operation? - ...
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3answers
125 views

Not understanding why in overcurrent protection only a certain section will isolate (why not the whole system)

I'm having an issue understanding a simple concept for faults. I understand the principles of how the relays cause the circuit breaker to open etc when a larger current goes through them to provide ...
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1answer
549 views

Factors that limit maximum power transfer through transmission lines?

I have read that the maximum power transfer is limited by (1) Thermal Limit, (2) Voltage Regulation and (3) Transmission angle (Stability). Thermal limit is self-explanatory. Is voltage regulation ...
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1answer
44 views

From how wide a range of angles can a grid of dipole antennas efficiently receive a power beam?

This paper on solar power satellite concepts makes brief reference to the ground receiver receiving an elliptical beam due to the angle it is at to the transmitter (2nd paragraph). The angle isn't ...
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0answers
43 views

Partition of state space in 2-dimensional Euclidean space

I'm working on creating a state space model with DC-OPF solutions. I have a 3-bus system and hence, a 2-dimensional state space. Under DC-OPF the states are voltage phase angles. I'd like to model a ...
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2answers
175 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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1answer
219 views

BOOST CONVERTER Simulation Problems in Multisim

I am trying to simulate a boost converter to step up the voltage to 70V from a 40V source on the Load resistor. Based on the formula: Vout =Vs(1/1-D), i calculated the duty cycle to be 42.85% however ...
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1answer
43 views

How to decide where to place devices for power quality handeling [closed]

In a facility that experienced voltage sags where 175 KVA of the load is sensitive, and we are asked to implement MG set or flywheels to handle the power quality issues. where should the MG set/ ...
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2answers
427 views

How to choose the receiving end voltage for a transmission line using a short line approximation

I am confused as to how to choose the receiving end voltage for a short line approximation For example if i have a 220kV transmission line at 50Hz at 60Km. At the end of teh line theirs a load of ...
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0answers
54 views

Transmission Line Voltage Terminology Confusion (Very Basic)

I have a issue interpreting what transmission line voltage actually means (I have tried researching but nothing clearly explains in detail, just says its a 110kV line etc).For example if i have a ...