⚡ Harmonic Resonance Simulation
1. Simulation Controls
2. Electrical System
50 Hz
Source
Inductance L
C
The electrical system contains inductance and capacitance. Together they can form a resonant circuit. When the frequency of a harmonic approaches the natural frequency of this LC system, the harmonic component can be strongly amplified.
3. Resonance Calculation
4. Oscilloscope — Voltage and Current
The upper waveform represents the harmonic voltage. The lower waveform represents the resulting harmonic current. Near resonance, the current amplitude increases dramatically.
5. Resonance Curve
The vertical axis represents relative amplification. The peak occurs when the harmonic frequency approaches the natural resonant frequency.
⚠ What Happens During Harmonic Resonance?
- Harmonic current can become greatly amplified.
- Capacitors may experience excessive current and heating.
- Harmonic voltage can increase substantially.
- Transformers can experience additional heating and losses.
- Motors can experience torque pulsation, vibration and heating.
- Protective devices may experience nuisance tripping.
- Severe resonance can contribute to equipment failure.
🛠 Resonance Mitigation
The Apply Detuned Filter button shifts the effective resonant frequency away from the selected harmonic. This demonstrates the basic principle of using reactors and detuned capacitor banks to reduce resonance risk.
- Detuned capacitor banks
- Series reactors
- Passive harmonic filters
- Active harmonic filters
- Appropriate system impedance management
- Properly designed capacitor-bank installations
6. Learning Experiment
- Select the 5th harmonic.
- Set the fundamental frequency to 50 Hz.
- The 5th harmonic becomes 250 Hz.
- Set the natural resonant frequency to approximately 250 Hz.
- Observe the resonance indicator.
- Watch the current waveform increase.
- Move the resonant frequency away from 250 Hz.
- Observe the reduction in amplification.
- Press Apply Detuned Filter and observe the change.