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# Questions tagged [power-flow-analysis]

Power flow analysis is a steady-state analysis whose target is to determine the voltages, currents, and real and reactive power flows in a system under a given load conditions.

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### Why am I getting completely different voltage and power results from Simscape phasor simulation and load flow simulation?

I am simulating the power system in the picture, with two generators and three PQ loads. My problem is that when I try to simulate it in Simscape, the load flow analysis gives me completely different ...
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### Why 230 V shows up in a staircase light circuit even though 'live' is disconnected? Why is there no continuity between the light bulb and neutral?

There's a staircase light circuit in my house similar to the one shown below. I disconnected 'live' from the switch on the left and measured the voltage between its 'L1' terminal and neutral and then ...
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1 vote
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### Reversal of power through a electric transmission line

From my undergraduate classes I know that active power flows from the bus with the higher power angle $\delta$ to the bus with a lower power angle. If I want to reverse the direction of power flow I ...
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3 answers
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### Difference between voltage and phase angle

The voltage at a node can be described by $$V = |V|e^{j \delta}$$ in which $\delta$ is the voltage angle. Voltage angles are required to calculate AC power flows. The phase angle if often ...
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2 answers
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### How is this capacitance affecting other parts of the circuit?

I'm attempting to drive a matrix of LEDs. Columns. Rows. It flickers too much for my liking, so I tried smoothing the LEDs with capacitors, but I'm getting very odd behaviour. Here is a minimal ...
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### How to calculate target impedance for the power trace if it is connected to multiple loads?

In this image, the source 3.3V, which is going to three loads(U1,U2,U3), that consumes current of 2A,0.5A and 1A respectively, As the total current is 3.5A. Lets consider allowable ripple, U1-2% U2-3% ...
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### Why is the change in reactive power not equal to the line reactance drop?

I am working on an equivalent network of a two bus system right now. I know the $P$, $Q$ and power factor at Bus 2. Bus 1 is taken as a slack bus ($V = 1 PU$, $\delta$ = 0). Using iterative ...
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### Clear my confusion on PV or PQ nodes of power system with renewables?

A solar PV is connected to a node of the power system through a converter circuit. Is it possible to understand that the solar PV operating at its maximum power point (MPP) is considered a PQ node? Or ...
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### Why does electricity flow into a capacitor (charged the other way round) but not into into a diode in this circuit?

I'm trying to understand the workings of the following circuit that I've both emulated and built physically so I know it does work (I did it in a different simulator, but I've redrawn it here for your ...
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### How can I check if a relay module is conducting electricity?

I want to know if a 5V water pump connected to a classical relay module which is connected to (SBC) ESP32s's GPIO can check if there was a failure in water pump and no electricity is flowing through ...
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1 answer
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### How to change per unit base before power flow calculation

I want to change the per unit base from transformers to a grid. My understanding can be illustrated by the following example (from example 3.4 in [glover2017power]). To be specific, $V_\text{base1}$ ...
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### Gauss Seidel method for power flow analysis

I need to write a matlab code for a power flow analysis using the Gauss-Seidel method. I have done the first part of the question, but I cannot figure out how to do the second one. The figure given on ...
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### What keeps voltage/current/power from flowing into "branch two" from the "Vout" node in the below drawing?

I need Vin to go into one of two branches and then continue to Vout, the boxes represent DC-DC converter, one at 20V and another at 15V. What keeps voltage from going through Branch 1 into Vout node ...
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### Is electric voltage fade in and fade out?

Consider theres a LED through switch with power from DC power supply. It will on when switch is close and off when switch is open. From closed switch we open the switch, so the LED will turned off. ...
2 votes
6 answers
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### When we can say 0 and 1 in digital electronic?

I'm confused when seeing wires contain GND and VCC in a schematic. Mainly their flows. I never confused when see in digital logic wires schematic like logic gates. I understand flows in digital ...
2 votes
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149 views

### Slack bus is the grid?

At the slack bus, there is a generator that can change his output instantly. I was wondering if exists in the grid this generator. We use it to study power flow problems but I don't think that there ...
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2 answers
661 views

### How to determine current flow direction in a circuit?

I have this diagram: The datasheet specifies I should bias the COMM+ line around 1.5V. However, when I measure the voltage at TP1 with the oscilloscope probe connected to ground, the output from the ...
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### Error in the direct approach for power flow calculation

In the famous paper [teng2003direct] on direct formulation of power flow calculation for power distribution networks, there is a simplification in converting nodal current injections to line current ...
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1 answer
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### Voltage sensitivity coefficients for unbalanced radial distribution feeders

I am wondering if my implementation of voltage sensitivity coefficients for unbalanced three-phase-four-wire radial distribution feeders is correct. We got $\bar{V}$ for phase(s) of all the buses ...
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1 answer
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### How to calculate load flow/power flow in a DC grid?

From my understanding this depends exclusively on the voltage level, but I have not found documentation about how this happens or is done. Is it purely based on KCL? Are there any tools or procedures ...
1 vote
1 answer
784 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 ...
6 votes
3 answers
600 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 ...
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### Power line rating conversion

How do I convert a real power line limit to a current flow magnitude line limit? Specifically, for a line connecting bus $i$ to bus $k$ (with $j$ denoting the imaginary element), I compute ...
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1 answer
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### Matrix-Vector equation for active and reactive power in a transmission line

Suppose that we know vtilde (the complex voltage phasor vector at all buses), C the incidence matrix for a network, ...
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1 answer
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### Power Flow Analysis

So I have this network in the figure below (100 MVA base) that I need to model with DC power flow line reactances and etc. Im attempting to set up the estimation matrix and have the following, but ...
2 votes
1 answer
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### Help with a DC motor speed controller circuit

I have a circuit which i'm trying to rebuild because the original stopped working due to a short-circuit (mechanical caused) First i copied exactly how the circuit was made, with no modifications and ...
1 vote
0 answers
210 views

### Change in frequency in a grid that has lost generation?

I have an example about droop and it asks to calculate final frequency in a grid after one generator power generation is lost. The answer is given as 59.889 Hz; however, I am calculating as 59.99 Hz. ...
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### Symmetrical three-phase power flow problem, √3

I have done quite a lot of research regarding the power flow problem for the steady state operation of an electric system. In many papers about the power flow problem the power flow equation are ...
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1 answer
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### Power flow analysis issue

simulate this circuit – Schematic created using CircuitLab I'm trying to get the hang of power flow analysis and I can't figure out how to measure the power (P and Q) between two inductances. [...
2 votes
1 answer
796 views

### Harmonic Power Flow

What is the fundamental differences between the conventional AC Power Flow (CPF) & Harmonic Power Flow (HPF)? Is HPF simply a combination of CPFs at different frequencies? Instead of finding the ...
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7 votes
2 answers
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### Equations of Power Flow Between Buses

I'm working in a MATLAB algorithm to compute the state estimation of a power system given some measures. The classical method computes a Jacobian matrix of all the measures, so I have to program all ...
6 votes
1 answer
3k views

### How to deal with optimal power flow problem in MATLAB?

I am writing an optimal power flow (OPF) program. OPF is an optimization problem in which some decision variables like Generation, Load dispatch are adjusted in power flow program so as to minimize ...
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4 answers
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### Large power-systems for power-flow study

I have just been started on a research project which involves finding ways to speed up the solution time of the power-flow problem which is basically calculating voltages at each of the buses of a ...