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

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Function Transfert Closed Loop PI regulation

i have a transfer function and i need to calculate the PI coefficient in closed Loop Transfer function H(s) = -3.766/(1+ 3.766*10^-3 s) PI transfer function ...
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22 views

Which appropriate DSP to calculate FFT(1024 pt) in a short time and with low power consumption? [closed]

I want to choose a DSP 3.3 V I/O to calculate FFT (1024 pts) in a short time and with a low power consumption because it will powered via an energy harvesting Thanks
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3answers
81 views

Is power rating of transformer determined by input or load?

Scenario: I have current carrying conductor with a current transformer around it. If the load is rated at 5V, 2A and only requires 2W of power, but the primary side conductor is carrying 100V 12A. ...
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1answer
32 views

Low weight split core transformer on 11kVA transmission line

I've seen transmission line energy harvester's that utilise a split core transformer. Here is an example. However, I fail to see how this is possible when a transformer cores which are small enough ...
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1answer
32 views

generator impedance and resistance

If i have a generator with a reactive component and resistive component are these in series of parallel? and When considering the impedance of a transmission line, should the impedance from the ...
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1answer
19 views

Certain property of a bus admittance matrix

I have got a simple network for my assignment: I know bus admittance matrix have certain properties that let us form the matrix without writing so many lines of ...
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1answer
27 views

Is it possible to set initial state to a simulink model to do simulations?

Consider that I have built an electrical circuit, or a power system or any other at Simulink and to do simulations, Simulink should work in the sense that it builds a state space model of the system, ...
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1answer
90 views

Reason for High voltage difference between Ground and neutral wire in 3 phase system

I have following reading of voltages: RY 397V RB 398V YB 393V RN 231V YN 227V BN 228V RG 386V * YG 385V * BG 10V * NG 216V * If you clearly observe data above phase-to-phase voltages ...
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1answer
27 views

Direct control over Real and Reactive charge/discharge in a battery/inverter AC system

In a paper (page 31) discussing the installation of a battery(*) in an electricity substation, UK Power discuss the ability to control the real power and reactive power components. They go so far as ...
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38 views

What's the efficiency of AC/DC and DC/AC conversion for high-voltage DC transmission?

According to this article, the conversion for HVDC is done with thyristor valves: http://electrical-engineering-portal.com/analysing-the-costs-of-high-voltage-direct-current-hvdc-transmission ...
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1answer
49 views

Electrical Machines and Transformers

Why do we multiply by the square root of 3 to get the phase to phase voltage from the phase to neutral voltage? What would be the multiplication factor for a 6-phase system, where the adjacent phases ...
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35 views

working of J1 and J2 in this following Circuit?

In the following Self oscillating Step up converter how JFET (J1 and J2) do work ? i am unable to understand overall working of this Step up Converter.kindly brief the working also. Thank you
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57 views

string efficiency of a string insulator using Guard rings

Does gaurd rings used in power transmissions increases the string efficiency of a string insulator practically?If yes then how.
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110 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 ...
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1answer
90 views

One-third neutral and full neutral

This is my first question here; if its not good enough, please let me know. Thanks For underground cables, we can choose "concentric neutral cable" or "tape shielded cable". For the first ...
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5answers
5k views

Why don't we use neutral wire for to ground devices and earth wire for closing the circuit?

I know that the neutral point of a distribution transformer is connected to the grounding (earthing) wire so I thing they are the same. Can I use the neutral wire for protection purpose and connect ...
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21 views

Black body heat to current conversion

I have learnt about Seebeck effect and peltier effect in college physics, but it was more of theory than hands on numbers and practicals. Now is there a commercial or DIY module that can produce ...
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1answer
71 views

kilowatt meter is using a proportional voltage x amps to create watts problems

So if a kilowatt meter is using a proportional voltage x amps to create watts used then in a situation where. 1. A pump motor using lets say 220v single ph is running while or starts running during a ...
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1answer
62 views

Twin wire neutral

I work in the power distribution industry and recently came across a 3-phase LV circuit with "twin-wired neutral" (i.e. two neutral cables inter-winded, therefore five cables total). What would be the ...
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2answers
52 views

Can an audio receiver with a 130v-rated switching power supply be modified to be used without a power transformer?

I have a Harman Kardon AVR, imported from the US, which uses an SMPS (130v) that I will use in Asia. Is there a way to modify the component inside the Power supply so that I can use it without a ...
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0answers
46 views

What is Virtual Array Antenna?

What is virtual array antenna (VAA)? I have searched it everywhere but i was unable to find direct answer to this question. I know this concept was built from phased array antenna. Please explain ...
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6answers
709 views

Why do we need to install a power transformer for each high building?

I live in area where many high buildings are being built. Each building is more than 10 floors. A special room is made next to the main entrance or the garage. The room is designed for installing a ...
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1answer
99 views

A question about the sound of corona discharge

In my collage, We were doing an experiment of the air's Breakdown voltage . At the end of the experiment we were listening to the sound of corona (electric partial discharge). The power supply has the ...
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1answer
119 views

Electrical schematics component ID's

Is there a list of standard ID codes used for components on a schematic drawing that anyone can point to? e.g. K = Contactor S = Switch Y = Solenoid X = Terminal strip etc. Any list would be ...
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1answer
35 views

Appox. the Impedance of Single Phase Pole Transformers using only Nameplate Ratings?

I know the following of one pole transformer (don't have access to the nameplate): 333KVA, Z = 5.75 % 25kV/12kV Given another transformer, I don't know Z, but know it's rating and voltage ...
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2answers
153 views

How to calculate instantaneous active power from sampled values of voltage and current.?

I have sampled values of voltage (phase to ground) and current (line current). I can calculate instantaneous apparent power using: $$ P(i) = V_1(i)I_1(i) +V_2(i)I_2(i) +V_3(i)I_3(i), i\in [1,n]$$ ...
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40 views

Why am I getting different Voltage Losses?

The step-down transformer has a ratio of 10:1 $$P_{globe}=V_{globe}\cdot I_{globe}$$ $$P_{globe}=V_{globe}\cdot I_{globe}=\left( 2 \right)\cdot I_{globe}=4\ \mbox{W}$$ $$I_{globe}=2\; ...
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2answers
636 views

How to synchronize a generator on the electrical grid?

I've read many articles about paralleling two portable generators or synchronizing a power generator on the electrical grid. I have the theoretical background about that topic and I know the four ...
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1answer
114 views

Phasor Measurement Unit (PMU) vs Synchro-check Relay

What is the difference between a Phasor Measurement Unit (PMU) and a Synchro-check relay? I need to know if Synchro-check relay can be used as replacement for PMU in a Synchrophasor data system. We ...
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1answer
112 views

On load tap changer controller switching

A 20/25 MVA transformer has an On load tap changer (oltc). Here a HMK7 Controller is used to control the motor drive of oltc. Which seems like There are two buttons 1-N & N-1. Red seven segments ...
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2answers
76 views

What is the effect of heavy loads on the electrical grid?

When our neighbors turns on a motor, a bulb in our home turns off for a very very short time and then it turns on again. It is something like a quick flash but a man eye can notice it. Would you tell ...
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1answer
128 views

Deformation of Heated Transmission Cable in a Conduit

Say I have 2000' feet of single phase XLPE cable with a 4" outer diameter in a 6" conduit, for simplicity, assume the conduit's inner diameter is 6". Also assume the cable is pinned at both ends and ...
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3answers
362 views

Capacitor exploding in a paper plant

Two years ago I was in an internship in a paper plant in the Superintendence of Electrocontrol, in the area of maintenance of electrical equipment. Well, they had a problem regarding some capacitor ...
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2answers
700 views

What is the zero-sequence equivalent of a YNy0 transformer?

The zero sequence equivalent network of a YNy0 transformer with grounded primary is shown below (source). It looks like there is no connection between the primary and secondary side of the ...
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1answer
744 views

Difference between disconnector, circuit breaker and load break switch?

There are various types of devices available for carrying out the switching and tasks. I have a question about the differences between disconnectors, circuit breakers and load break switches ...
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1answer
156 views

What are these coils on transmission lines?

What are these coils? This was asked by doetoe in this physics.stackexchange Question Where I saw them (maybe six or eight pairs) they came in pairs, always on the same two lines, and they were ...
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0answers
82 views

What is the ramp rate of a battery used on the grid?

For grid applications, I am looking for typical ramp rate of Li-ion batteries. I am specifically interested in batteries used for frequency management. So suppose I have a 1MW grid connected battery ...
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3answers
58 views

Given thermal capability of a transformer, how to best estimate the voltage regulation?

I'm working with a system that has 3 2MVA transformers for which there is an existing estimate of the peak load and the power factor. The xfmrs appear to have a greater thermal capability than the ...
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1answer
88 views

Grid changeover switching

I am designing a changeover circuit that will switch the power of attached appliances between two electricity providers. The two AC mains are of 220V RMS voltage and 50Hz frequency sine waves. The two ...
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1answer
202 views

What is the cause of voltage phase shift in a power system?

What element(s) cause the phasor voltage to shift in a power system? Why does the voltage phase angle increase with distance in a power grid?
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2answers
4k 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, ...
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1answer
231 views

what is shunt charging in power systems?

I am currently working with Power World Simulator. When inserting transmission lines, there is a parameter called shunt charging. What is this and what effect does it have on power loss in the line?
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1answer
101 views

Is my current transformer rated for 11kV Tranmission line?

I'm using a current transformer to measure current on HV transmission lines. Except i'm finding it difficult to find a split core CT that will be rated for 11kV. My CT that i'm looking at is the ...
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1answer
95 views

Modelling grounding reactor as transformer

First: This is not a question about electronics, it's about large (three-phase) power systems where the components have ratings in kV and MVA. I'm mainly interested in symmetrical components, and how ...
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10answers
9k views

Why three-phase power? Why not a higher number of phases?

Is there a reason, beyond historical reasons, that three phases has become the dominant number of phases? I am aware of the advantages against one phase and two phase, namely the reduced amount of ...
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1answer
86 views

Voltage drop-out after lightning strike

A powerful thunderstorm rolled through my area yesterday and something happened that I had never noticed before. Many times before when powerful thunderstorms with lightning rolled through, the AC ...
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5answers
2k views

Why is the supply voltage 400V when the neutral is disabled in a three phase supply?

Why is the supply voltage 400V when the neutral is disabled in a three phase supply? Phase voltage is 230V. Line Voltage is 400V.
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1answer
148 views

range of transmission line?

I am not electrical engineer by profession. So, accept my apology if my question sounds stupid. I am simulating a situation on computer where electric power is being send from one point to another ...
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1answer
2k views

Low voltage power lines - formula for spacing between poles?

What is the distance or separation between pole-pole in a 230 VAC distribution line? Is there any formula for this, or we can take any distance?
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119 views

Connecting shielding for high and low voltages

I have design a power distribution PCB with high AC(230V) and low DC(<10V) voltage power rails. Both are going to be connected to my board by separate cables. Each of those cables have shielding ...