# 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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55 views

### Voltage Collapse in Power Systems: Loss of steady state?

I've read some papers on voltage collapse, and it seems to be described as the loss of a steady state solution for the system equations. Where the Jacobian matrix is singular, and voltage is ...
44 views

While building some small (single digit wattage) inductive power transmission systems, I wondered if a larger one could be build using an induction cooker as transmitter. What would be the mandatory ...
39 views

### DC Distribution System Numerical Problem [duplicate]

I have attempted to solve this problem but the answers don't match. Where am I making a mistake?
65 views

### Where is my mistake in this power distribution system homework question? [closed]

I have attempted to solve this problem, but the answers don't match. Where am I making a mistake?
20 views

### Smart meters data correction average time

In the context of smart grids, what is the average time delay of measurements correction provided by smart meter data/AMI data, given that some of the meters may provide incomplete readings because of ...
26 views

### Transmission line current magnitude

I want to compute the current magnitude in a transmission line. The line has properties b (total line charging susceptance, p.u.), ...
56 views

### Why will we get the wrong answer if we use $I_1=\frac{V_1}{Z_1}$ to calculate $I_1$ directly?

There is a transformer with $600V/120V$, and the impedance in the high voltage side is $52-30j Ω$, and there is a loading, which impedance is $0.8∠10°Ω$, connected with the low voltage side. ...
36 views

### Troubles on understanding datasheet of a 24V DC permanent magnet motor

Can you help me on understanding this datasheet of a DC Permanent Magnets motor? Note that the deleted parts do not add information, they are those not translated into English or referring to other ...
57 views

### Which solution is right for this question? I think both of the solutions make sense

There is a multiple choice question: $$V_{G1}=10cos(10t+60°)$$ and $$V_{G2}=5cos(10t)$$ The resistance of the wire is $R=10Ω$, which one is the power that $G_1$ transmits? A. 1.25W B. 1.5W ...
21 views

### TN-S system neutral point earth resistance

According to many sources on the internet, a secondary neutral earth resistor is added at the distribution stations (transformers) to reduce the earth fault current. My question is when using a TN-S ...
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### Finding the impedance of a distribution line from R,X,C values

I have real industry data of distribution feeder with line data consisting of r ,x and c values as shown in the attached figure. ...
27 views

### Which case count as leading PF in Salient plot generator?

In the figure above we can see the location of two armature currents. In case 1, $I_{a1}$ is leading $Vt$ (terminal voltage) but lagging $E_f$ (excitation voltage). In case 2, it is obvious that ...
28 views

### High voltage pulses amplification

Let's consider this scheme: With this scheme I wanted to get a pulse of duration 10uS with very high amplitude, starting by the same pulse with 10V amplitude. I need to get a peak of about 400V (...
41 views

### Inductance of a three-phase transmission line

I was studying the difference between distribution and transmission lines and read that, because of the larger separation among the conductors, the transmission lines have comparatively higher flux ...
115 views

### Ghosting on Nixie Tube Clock

I have problem with my nixie clock. There are ghosts when changing numbers on the lamps. I'm using multiplexing with TLP627 opto-coupler to control anodes and NPN MMBTA42 bipolar transistors to ...
37 views

### Instantaneous and active power in an ideal switch powered by real source and squared wave

This is a somewhat theoretical question, but one that has some impact on power theory. The circuit in the figure is composed of a real DC source (with non-negligible internal resistance) and feeds a ...
35 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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### Transmission Line Impedance 3 phase

I have the following question that I can't seem to figure out. The question ask to solve for the impedance of a 3ph transmission line. I've found the De (distance relative distance) and XL using the ...
66 views

### How can I compute the power flow for a network with transformers (as in the WECC 9 network)?

I'm trying to solve the power flow for the WECC-9 bus reported below: all generators (1,2 and 3) are behind a transformer, which has a Voltage converter ratio (e.g. 18/230) and a reactance(?), which ...
103 views

### How does the arc extinguisher work in a miniature circuit breaker?

In a miniature circuit breaker, as shown below, the distance between open contacts is much less than the distance between metal bars in the arc extinguisher part (the gap gets progressively longer ...
28 views

### Grid Tie Inverter Anti islanding

I was wondering about anti islanding design. Using grid tie inverters is usually the best choice when not investing in batteries, but suppose you have batteries and want the confort of grid tie AND ...
152 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 ...
31 views

### Power management switch for Low-Power Application

In my low-power application I have a MCU waiting for an interrupt to wake up. (see picture) There are two sensor ICs (IC1, IC2) which consume very little and wake up the MCU via the interrupts. After ...
26 views

### 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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### Can we use the Halbach array configuration in an electromagnet?

I tried asking this question in several forums but didn't find any answers as i expected. It's very hard to find information about halbach array in google, especially in the electromagnetic field. We ...
13k views

### What is the speed of “electricity”?

In a distribution grid, what is the speed of energy signal Is it strictly the same? And how is synchronisation achieved? Is an electric grid essentially an orchestra where everyone is the chief ...
516 views

### Producers consumers balance in the grid

In a large distribution grid, it is said that consumers and producers must be in balance; what that means physically, in correct (not simplistic) mathematical formulation, is not clear: perfect ...
61 views

### Constant current and constant voltage control of inverter

Most of inverters in the grid are based on constant current control where inner current control loop tries to limit the current. Hence acting as a constant current source. I was wondering how control ...
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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### linear model of a power load at the end of a transmission line

I am working on a controller that will regulate the voltage at the end of a transmission line into a variable load. I am able to ignore the inductive effects of the line at the frequencies of interst, ...
63 views

### Real Power or Reactive Power in Superconducting Motors?

My circuits class is teaching that in AC power, there are two kinds of loads. One is a resistive load, with absorbs power at all times. The other is a reactive load, which absorbs zero average power. ...