Capacitor Bank Transient Analysis and Fault Detection

Capacitor banks are widely employed in electrical networks for reactive power compensation, voltage support and power-factor correction. Their switching operations, however, give rise to transient phenomena—manifested as high‐amplitude inrush currents, voltage oscillations and potential resonance with network inductances. If unchecked, these transients can damage switchgear, distort voltage waveforms and compromise supply reliability. Internal faults within a bank, such as dielectric breakdown or fuse failures, produce characteristic unbalanced currents and subtle capacitance changes. Conventional protection schemes rely on unbalance relays that detect current or voltage asymmetries but often lack the capacity to discriminate between internal and external faults or to pinpoint the faulted element. Modern research combines electromagnetic simulation, advanced signal processing and online parameter estimation to enhance early fault detection, classification and localisation. Techniques such as discrete wavelet transform, phasor analysis and statistical monitoring enable operators to identify incipient faults, initiate targeted maintenance and mitigate the risk of widespread outages. Such advances are critical for grids facing increasing load variability, renewable integration and stringent power-quality requirements.

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Capacitor Bank Transient Analysis and Fault Detection publication trend

The graph below shows the total number of articles in capacitor bank transient analysis and fault detection across all publications each year (not limited to Nature Index journals).

Technical terms

Capacitor bank: A collection of capacitors connected in series and/or parallel to supply reactive power compensation and voltage support in power networks.

Transient inrush current: A brief, high-magnitude current surge occurring when a capacitor bank is energised or switched, which can stress circuit breakers and insulation.

Unbalance relay: A protection device that monitors phase-current or phase-voltage asymmetries in three-phase systems to detect internal faults.

Discrete wavelet transform (DWT): A signal-processing method that decomposes time-domain signals into components across multiple frequency bands, facilitating the detection of transient events and fault features.

Phasor measurement: A technique representing sinusoidal voltages or currents by their magnitude and phase angle, used for real-time monitoring and protection in power systems.

References

1. On-Line Monitoring of Shunt Capacitor Bank Based on Relay Protection Device. Energies (2023).
2. Behaviour analysis of H‐bridge high‐voltage capacitor banks fault on 230‐kV substation using discrete wavelet transform. IET Generation Transmission & Distribution (2023).
3. Analyzing the Characteristics of Faults in a Transmission Line and High Voltage Capacitor Banks in a 115-kV-Power System Using Discrete Wavelet Transform. IEEE Access (2022).