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Power Capacitor Resonance Issues and Solutions

Rockwill 08/09/2025

01 Resonance Phenomena in Power Capacitors
• Definition and Hazards of Resonance Phenomena
Power capacitors play a critical role in power systems but may occasionally encounter a unique phenomenon—resonance. Simply put, resonance occurs when power capacitors resonate with inductive or capacitive components in the system, causing abnormal fluctuations in current or voltage. This resonance phenomenon can severely impact the stable operation of power systems and may even lead to equipment damage or accidents. Therefore, understanding and mastering methods to prevent the hazards caused by power capacitor resonance is of paramount importance.

• Causes and Consequences of Resonance Phenomena
In power systems, resonance issues in power capacitors demand serious attention. Improper parameter selection may cause capacitors to resonate under harmonic influence, leading to overvoltage and sharp current surges that severely threaten the system. Resonance occurs when the system’s natural frequency aligns with the capacitor’s operating frequency, resulting in frequency synchronization and superimposed capacitor currents. This phenomenon poses critical risks: it may trigger dangerous overvoltage and amplify overload currents to dozens of times normal levels, jeopardizing power systems and associated equipment. Consequently, enterprises must vigilantly monitor power factors approaching 1 and ensure the use of series reactors matched with power capacitors to suppress resonance and mitigate harmonic currents.

02 Causes and Prevention Measures of Resonance
• Causes of Resonance
During power capacitor operation, resonance may arise from multiple factors:

Neutral-point displacement causing elevated phase voltages, altering system currents and compromising compensation current adequacy.
Mismatched parameters between capacitors and series reactors, inducing harmonic currents.
Resonance becomes especially likely when harmonic frequencies approach the system’s resonant frequency.

Consequences and Prevention of Resonance
When harmonic current frequencies approach or match the resonant frequency with sufficient energy, they may induce resonance in power capacitors. This resonance can cause overvoltage, further elevating non-fault phase voltages and potentially piercing through internal components** of capacitors. To mitigate such risks—including overvoltage and capacitor damage—proactive measures include installing high-performance linear filtering devices and ensuring high-compatibility series reactors. These strategies effectively suppress resonance risks and safeguard power system stability.

03 Solutions
• Reactive Power Compensation & Harmonic Mitigation
As a critical aspect of power systems, ROCKWILL delivers professional solutions to address resonance issues and ensure system stability. Reactive power compensation and harmonic management are indispensable for robust grid performance. Committed to excellence, ROCKWILL leverages innovative technologies and premium products to help clients overcome resonance challenges during capacitor operation. Our solutions proactively ensure equipment reliability and extend service lifespan.