Abstract: This article describes methods to identify hazards and assess the risks associated with capacitor stored energy. Building on previous research, we establish practical thresholds for various hazards that are associated with stored capacitor energy, including shock, arc flash, short circuit heating, and acoustic energy release.
Some of the failure problems associated with capacitor banks are already known since they happen often. A few of the failures are traceable to the original source and sometimes that may be difficult to do. In many instances, the final result of a failure may be a catastrophic explosion of the capacitor into pieces or fire.
In the filter banks, the capacitor units are connected in series with inductors. Sometimes the voltage across the capacitor units exceeds the design values. In such circumstances, the capacitor units fail catastrophically due to inadequate voltage rating. 2. Fuse blowing
The capacitor banks tend to interact with the source or transformer inductance and produce ferroresonance. This can produce undamped oscillations in the current or voltage, depending on the type of resonance. If the system is not adequately damped, then there is a possibility of capacitance or transformer failure.
In power electric systems capacitors and capacitors banks, which must be in accordance with IEC Standards 60143 and 60871 or IEEE Standard 824, are used to: Compensate reactive energy (power factor correction) due to consumers (MV and LV) and the inductive effect of long overhead lines and underground cables (MV and MV).
Capacitors banks may have built-in discharge resistors to dissipate stored energy to a safe level within a few seconds after power is removed. Capacitors banks shall be stored with the terminals shorted, as protection from potentially dangerous voltages due to dielectric absorption.