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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.

43 questions with no upvoted or accepted answers
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157 views

### What are these parallel connected lines meant for?

During my walk today, I noticed these small parallel connected lines. What purpose do they serve?
125 views

### What is the purpose of these PTs?

What is the purpose of these PTs installed on the two coupled busbars? And we have whole panels in the HV room for these PTs. Kindly explain. (Photo attached)
35 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 ...
2k 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 ...
58 views

### How is AC load distributed across on-site generation and the utility?

I’m trying to understand the physics behind AC load distribution when distributed on-site generation is installed and the load is also connected to the grid. In the diagram below, I have a building ...
15 views

### How is voltage induced in Yd transformer without neutral connection sinusoidal?

Thia is regarding bank of 3 single-phase transformers having star connected primary with isolated neutral and delta connected secondary. I know that for bank of 3 single phase transformer core flux ...
41 views

let's consider AD8318, a chip which contains a logarithmic amplifier, often used for power measurements. I have read its datasheet and there is a thing that I do not understand: no maximum input RF ...
49 views

### Power Distribution for multiple 5V consumers

I'm a newby in the field of Electrical Engineering (only basic knowledge from school). Nevertheless, I need to power up to 10 Raspberry Pis (5V, 2A) with Dupont Connectors and AWG24 cables over GPIO ...
37 views

### Transistors' Scattering Parameters

I have some doubts about the Scattering Matrix of a transistor seen as a 3 port devices. Precisely, I read (for instance here) that we do not have 9 independent S parameters since there is this ...
31 views

I came across the terms 'Rectifier Loading Effect' and 'Rectifier Loading Factor' when reading IEEE Std 421.5-2005 Recommended Model for Power Stability Studies, mentioned in those ACxA models. What ...
146 views

### Off grid LED solar lighting without batteries

I have 2 COB LEDs (12-14V DC, 50W, I think with 3,75 A in data sheet). I need to run them with a solar panel, it should only run when there is sunlight no batteries needed. Using a 270W panel (open ...
131 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 ...
286 views

### dq0 Transformation Interpretation

What is the physical interpretation of dq0 axis transformation in electrical machines and power systems? How does this transformation helps? Thanks
426 views

### Power distribution boards - hierarchical numbering system

I wish to renumber the circuit breakers (and possibly the cables) in an industrial plant. Numbering should give a unique identifier for each breaker. Numbering should give a path back to the incoming ...
147 views

### Determining VA rating of the small transformers

I have a 1000VA toroid transformer which weighs 8 Kg. Based on this power-to-weight ratio, can I conclude that another transformer which is EI cored and weighs 7 Kg must be 875VA? Or such ratiometrics ...
496 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 ...
3k views

### What is a Thyristor Switched Series Capacitor (TSSC)?

I'm struggling to understand the physical difference between the Thyristor Switched Series Capacitor (TSSC) and the Thyristor Controlled Series Capacitor (TCSC). From this book, I understand that a ...
19 views

### Peak Current in a transmission line

Let's consider a transmission line (which drives a generic load ZL) connected to an AC voltage source. If we know that the peak voltage of the source is equal to Vp, how can we evaluate the peak ...
24 views

### Impact of Interconnection of One Energy Generating Plant At Another Generator Plant's Generator Bus Bar(PV Bus Bar)

As the scheme attached below, we're interconnecting 5.5 MW of generated power of upstream project(Around 2 km Away from the Interconnecting Switchyard) to the Generator Bus Bar(PV Bus Bar) on 11 kV ...
27 views

### Isolation voltage of a flyback transformer

How to calculate the isolation voltage of a planar flyback transformer? Or if there are any standards about it? I am designing a planar flyback transformer that need an isolation voltage of 1000V, ...
44 views

### Power Distribution Blocks for DC voltage?

So, I'm pretending to use a somewhat uncommon component for my generator system. With an alternator, I will generate 24 V DC and a maximum of 100 A. My question is, can I use a power distribution ...
20 views

### How the directional element in the distance relay blocks the reverse power flow?

Following is the figure for directional element of distance relay. The trip region is also in the second quadrant. How it will restrain from operating if the fault impedance is as indicated by F (in ...
13 views

27 views

### How to model P, V variations in PV buses in a load flow problem?

I'm trying to use the DC power flow results as a base, and modify it to approximate AC power flow results more accurately. So far, I have been able to do that in a few simple test cases from Matpower, ...
75 views

### What will be Resistance for maximum Power transfer from network A to network B?

simulate this circuit – Schematic created using CircuitLab Can we apply Maximum Power transfer theorem if we are given two networks both with voltage sources. In solution it was said that for ...
51 views

### How to have Wye-connected Potential Transformers(PTs) and Neutral Ground Resistor short circuit detection at my ground fault protection relay?

Detecting if the Neutral Ground Resistor (NGR) is shorted is something that must be checked at the Ground Fault Protecting Relay. The typical way to do this is to inject a DC component and to measure ...
126 views

### Trapezoidal Rule of Complex RLC Circuit using MATLAB

I am having difficulty trying to figure out how to solve this circuit using the trapezoidal rule. I know how to do so in a first and second order RLC circuit however this particular circuit is giving ...
46 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 ...
69 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 ...
55 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,...
62 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 ...
76 views

### How is the inverter connected to the grid?

I just finished circuit designing of an inverter which converts 440V DC to 230V AC. Now my manager asked me what kind of connectivity does it has. I answered him: "The current connectivity is AC as ...
33 views

### Low voltage grid frequency with renewable feed-in

If a low voltage grid's consumption equals to that grids renewable energy production, does it mean the transformator basically does nothing, like an open circuit? Are grid-tied inverters (smart) ...
247 views

### The critical clearing time (CCT) of a fault in DIgSILENT

How can I determine the critical clearing time (CCT) of a fault in DIgSILENT? How can I use DPL to determine the critical clearing time (CCT) of a fault in DIgSILENT?
65 views

### Smart grid communications

For my final project, I am looking about smart grid. What I want to know is that what kind of communication is done in smart grid and the appliances, protocols used etc. Can I extract a data whether ...
66 views

### To what extent are semiconductors used in high voltage and power grid electronics?

I'm thinking of silicon controlled rectifiers and HV thyristors. Why have vacuum tubes been phased out or have they? I believe that in some countries, power grid electronics is entirely tube-based ...
108 views

### Shorten the mini Christmas light strand

I need to shorten a 100 light strand of mini lights to just 18 lights. Based on the wiring, I believe the strand is engineered as two 50 light strands in parallel. The strand is rated for 120 V and ...
34 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 ...
693 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 ...
4k views

### Primary and secondary substation equipment

There are many devices that can be found in the substation. One of the categorizations for substation is between primary and secondary substation equipment. Which device types belong to each ...
88 views

### How can i record the rpm of a small spinning object with out the use of a hand held tool such as a laser.

How do I measure the revolutions of a moving object as it rotates around. Imagine a fan blade, I need to measure the rpm of the fan without using an outside tool such as a laser rpm reader. Ideally ...