Parallel Resonance in Power System

Click For Summary
The discussion focuses on the effects of a parallel resonance circuit in a power system when a passive filter is installed to target the 5th harmonic. It is noted that if the parallel circuit resonates at the 7th harmonic, it will not impede the flow of 7th harmonic currents, making it effectively "invisible" at that frequency. The fundamental frequency and all other harmonic currents, except for the 5th harmonic, can still flow freely between points A and B. The correction emphasizes that the 5th harmonic is bypassed by a series circuit resonating at its frequency. Overall, the interaction of harmonics in the system is crucial for understanding current flow dynamics.
LagCompensator
Messages
24
Reaction score
1
Hi,
imagine we have the following circuit shown in the figure below. There are installed a passive filter to filter the 5th harmonic. Now, after installation this creates a parallel path with a generator connected, let's say that this parallel circuit has a resonance frequency at the 7th harmonic. Then it turns out that some load further away causes 7th harmonic currents to flow and thus exciting the parallel resonance circuit.

  1. Would this cause Z to go to infinity in theory assuming ideal components and thus stop the flow of 7th harmonic currents from A to B shown in the figure below?
  2. Would fundamental currents and other harmonic currents except for the 7th be able to flow between A and B?
parallel resonance.png
 

Attachments

  • parallel resonance.png
    parallel resonance.png
    10.9 KB · Views: 480
Engineering news on Phys.org
LagCompensator said:
Hi,
imagine we have the following circuit shown in the figure below. There are installed a passive filter to filter the 5th harmonic. Now, after installation this creates a parallel path with a generator connected, let's say that this parallel circuit has a resonance frequency at the 7th harmonic. Then it turns out that some load further away causes 7th harmonic currents to flow and thus exciting the parallel resonance circuit.

  1. Would this cause Z to go to infinity in theory assuming ideal components and thus stop the flow of 7th harmonic currents from A to B shown in the figure below?
  2. Would fundamental currents and other harmonic currents except for the 7th be able to flow between A and B?
View attachment 109704
1) If the line is shunted by a parallel circuit resonant at the 7th harmonic, it will not impede the flow of 7th harmonic currents in the line. It is invisible at this frequency.
2) The 5th harmonic will be bypassed by the parallel circuit resonant at its frequency but the fundamental and all other frequencies can freely pass between A and B.
 
  • Like
Likes LagCompensator
tech99 said:
1) If the line is shunted by a parallel circuit resonant at the 7th harmonic, it will not impede the flow of 7th harmonic currents in the line. It is invisible at this frequency.
2) The 5th harmonic will be bypassed by the parallel circuit resonant at its frequency but the fundamental and all other frequencies can freely pass between A and B.
Correction:
2) The 5th harmonic will be bypassed by the SERIES! circuit resonant at its frequency but the fundamental and all other frequencies can freely pass between A and B.
 
I am trying to understand how transferring electric from the powerplant to my house is more effective using high voltage. The suggested explanation that the current is equal to the power supply divided by the voltage, and hence higher voltage leads to lower current and as a result to a lower power loss on the conductives is very confusing me. I know that the current is determined by the voltage and the resistance, and not by a power capability - which defines a limit to the allowable...

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
2
Views
2K
Replies
2
Views
1K
  • · Replies 28 ·
Replies
28
Views
1K
  • · Replies 41 ·
2
Replies
41
Views
7K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 16 ·
Replies
16
Views
4K