The order of the sub-harmonic during SSR for 50 Hz normal frequency is

The order of the sub-harmonic during SSR for 50 Hz normal frequency is

Right Answer is:

50/3 HZ

SOLUTION

Sub-synchronous resonance

  • The transient currents at the sub-harmonic frequency resulted in a series-compensated network due to a switching operation or a fault.
  • These sub-harmonic frequency currents assume dangerously high values and even become unstable.
  • The unstable operation is exhibited in the form of negative resistance in the equivalent circuit of synchronous and induction motors.
  • Sub-synchronous resonance (SSR) is a phenomenon in which electrical energy is exchanged between generators and transmission systems below the nominal power frequency (50/60Hz).
  • Synchronous Resonance (SSR) is a phenomenon in which electrical energy is exchanged between generators and transmission systems below power frequency.
  • It can be caused due to interaction of a series compensated transmission line with a generator; in addition, results in oscillation in the shaft and power swing.
  • The subsynchronous frequency is typically 1/3 of the fundamental frequency. So for 50 Hz fundamental frequency, the subsynchronous frequency is 50/3 Hz.
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