Negative sequence (Symmetrical component)

In summary, if you know the values of Ia, Ib, and Ic in a balanced load situation, you can use the symmetrical transformation to find the negative sequence current (I2). However, if the system is imbalanced due to a fault, the values of Ia, Ib, and Ic may not accurately reflect the negative sequence current (I2).
  • #1
sarayut
2
0
I'd like to know how do i find I2 (Negative sequence current) if I know Ia, Ib and Ic but don't know angle (in normal system_not fault)? My system's 3 phases 3 wires.
 
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  • #2
You need to specify what you mean by "normal system_not fault"?

Is the load balanced? If so, you know the angles relative to each other. You can then use the symmetrical transformation to find if there is a negative sequence current.

http://en.wikipedia.org/wiki/Symmetrical_components
 
  • #3
Thank you very much for answer!, "Normal system_not fault" mean imbalance situation in distribution system. For example Ia= 85 A, Ib= 92 A and Ic= 90 A. I'd like to know I2 for set the I2 pick up to detect low fault current.
 

Related to Negative sequence (Symmetrical component)

What is negative sequence in electrical systems?

Negative sequence is a type of unbalance in three-phase electrical systems where the three phases have unequal magnitudes and/or phase angles. It is caused by an asymmetrical fault or by unbalanced loads.

How is negative sequence represented in symmetrical components?

Negative sequence is represented by the negative sequence component in symmetrical components analysis. It is one of the three components used to analyze and understand unbalanced conditions in three-phase systems.

What are the effects of negative sequence on electrical systems?

Negative sequence can cause overheating and damage to equipment, voltage fluctuations, and increased power losses. It can also lead to motor torque pulsations and reduced motor efficiency.

How is negative sequence detected and measured in electrical systems?

Negative sequence can be detected and measured using specialized instruments such as sequence component monitors and power quality analyzers. These instruments can analyze the voltage and current waveforms to identify the presence and magnitude of negative sequence.

How can negative sequence be mitigated and corrected in electrical systems?

Negative sequence can be mitigated and corrected by balancing the three-phase loads, improving the grounding system, and using specialized equipment such as static VAR compensators. Additionally, proper maintenance and regular testing can help identify and address any negative sequence conditions in the system.

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