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

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36 views

How is solar power consumed before grid power

This one has been on my mind for a while now... I recently installed rooftop solar panels with micro-inverters. While I was informed I would be using the solar power first, and any remaining needs ...
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0answers
27 views

Voltage distribution in IC in MATLAB Simulink

I tried to simulate the IC IR2121 using simulink. I am trying to test the IC that I simulated. When I connect the voltage source directly to the Vcc, it gives an error stating that the current ...
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2answers
91 views

Where is Electric ground comes in missiles and rockets using high voltages ?

I may sound silly. I think that the Rocket systems and missiles might be having high power amplifiers and circuits inside them. Then how the Electric ground is accommodated in those kind of circuits. ...
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1answer
32 views

Changing the torque and excitation in an alternator

What is the effect of changing the input torque of an alternator with excitation kept constant? and what is the effect of changing its excitation with a constant torque?
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3answers
119 views

How does the Electrical Grid React to Large Changes in Supply or Demand?

Background I'm performing some research for a software project that monitors power generation and consumption for a large fictional spaceship. My rationale is I'd like to first understand how real-...
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2answers
4k views

Why do condors get electrocuted by power lines?

Plenty has been said about why birds are safe to land on power lines. But condors, apparently, are not. The linked article explains that condors are electrocuted often enough and endangered enough ...
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1answer
31 views

Battery Pack Configuration

I currently am using Li-FePO4 cells in the configuration below (picture): I'm researching how to build a passive cell balancer for this battery pack. Though I'm getting confused on some specs I'm ...
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2answers
59 views

When can I use the formula P=V^2/R?

I'm currently learning about the transportation of electrical energy through power lines. I now know that transporting current at a very high voltage cause minimal power loss compared to transporting ...
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0answers
21 views

Typical values of G (condutance) and B (susceptance) of a real line

I'm modeling power flow of a grid and in order to solve some equations I calculated values of G (condutance) and B (susceptance) from R (resistance) and X (reactance) data of my lines. I used: G=R/(R^...
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7answers
360 views

The physical meaning of inductance

What is the the physical meaning of inductance? We know that the resistance "R" of a conductor is how easily the electrons flow through it...etc but what about the inductance "X" ?
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33 views

Is there any easily understandable IEEE test feeders (~ 100 nodes) by computer scientists?

I want to simulate some power flow algorithms over IEEE test feeders. Since I am from the area of computer science, I find it difficult to understand many technical details in IEEE distribution test ...
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1answer
24 views

Method for Measuring Power Flow in a Distribution Network?

Considering a mostly meshed distribution network (with some radial spurs) connecting zone substations (loads) to grid exit points (GXPs or sources). I am attempting to find the proportion of the ...
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1answer
47 views

Strong and a weak grid? [closed]

What is difference between a strong and a weak grid? How can these be simulated in simulink? ?
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44 views

Difference between instantaneous, definite time and inverse time over current protection relays

Protection coordination is very important in transmission and distribution power networks. One of the most widely used and important protection relays are over current protection relays. What is the ...
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2answers
120 views

Hooking two (gasoline) generators together to make 220VAC

A question was posed on the Home Improvement SE... Can I buy or make an adapter to hook 2 generators together to run a 220 volt welder? Any contribution to this thread (from an electrical engineer) ...
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0answers
89 views

How to calculate the earth fault current in a transmission system with no ground wire?

Background information, and my thought on the matter are provided in the end of the question. I need to calculate the fault current in case a fault occur for instance 10 km away from a transformer ...
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0answers
25 views

How many measurements does a typical phasor meqasurement unit (PMU) capture?

How many phasor measurements (voltage amplitude and phase angle) does a typical PMU capture from 1) transmission and 2) distribution lines? is it one, three, or more? Does this depend on the topology ...
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0answers
23 views

SiC Schottky power diode MATLAB simulation issue

Hi Everyone (first time poster), I am modelling a 4H-SiC Schottky power diode in MATLAB and I have come into some issues with MATLAB when trying to make an I-V curve. I was reading this paper and I ...
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0answers
25 views

Power transformer configuration: What factors affects the choice of a power transformer

How a specific type of power transformer (\$\Delta/\Delta, \Delta/Y\$ etc) is chosen for various step-ups and step-downs. In which case ungrounded neutral or Peterson coil grounding is preferred.
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41 views

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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3answers
90 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
37 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
37 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
22 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
41 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
192 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
44 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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0answers
48 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 High-...
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1answer
55 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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0answers
40 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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101 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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2answers
137 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
126 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 one,...
22
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5answers
6k 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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22 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
73 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
68 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 bulky,...
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0answers
76 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
1k 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 ...
2
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2answers
141 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
139 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 ...
0
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1answer
41 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
211 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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1answer
44 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\; \mbox{A}\; ...
4
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2answers
2k 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
145 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
138 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
79 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 ...
2
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1answer
146 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 ...