SMD Aluminum Electrolytic Capacitor

Photocoupler

Power capacitors play a crucial role in power distribution systems by compensating for reactive power and improving the power factor. Most loads in an electrical system are inductive, meaning the current lags behind the voltage by 90 degrees. When a power capacitor is connected to the system, it generates a current that leads the voltage by 90 degrees. This opposing current helps cancel out part of the inductive current, effectively reducing the overall reactive power demand and improving system efficiency.

When using power capacitors, it's essential to ensure safe and efficient operation. The capacitor should be operated at its rated voltage, not exceeding 1.05 times the rated value. However, it can tolerate up to 1.1 times the rated voltage for a limited period—up to one hour. If the voltage exceeds this threshold, the capacitor should be immediately disconnected to prevent overheating or internal damage. High voltage can cause the capacitor to become overloaded, potentially leading to failure or even explosion.

Additionally, over-compensation or reactive power reversal after equipment shutdown must be avoided. This can lead to unnecessary energy loss and instability in the system. The typical ambient temperature for capacitor operation ranges from -20°C to +45°C. Operating outside this range may cause bulging, oil leakage, or reduced lifespan. It’s also important to maintain indoor humidity below 80% to prevent moisture-related issues.

Maintenance is key to ensuring the long-term performance and reliability of power capacitors. Regular checks should include visual inspections for signs of oil leakage, swelling, cracks, or overheated terminals. Any abnormality found should prompt immediate shutdown to prevent accidents.

Monitoring the voltage during operation is also critical. Voltage fluctuations due to load changes can affect capacitor performance. It’s recommended to use automatic switching devices whenever possible. If automatic systems fail, manual adjustment based on load conditions is necessary to avoid overcompensation or reactive reversal.

Checking the current is another important maintenance task. Power capacitors should operate within their rated current limits, but they can handle up to 1.3 times the rated current for short periods. Exceeding this limit may cause the capacitor to overheat or burn out. Therefore, if the current goes beyond this threshold, the capacitor should be taken offline to prevent damage.

In summary, proper installation, regular maintenance, and careful monitoring of operating conditions are essential for the reliable and efficient operation of power capacitors. Following these guidelines not only extends the service life of the capacitors but also contributes to the overall stability and safety of the power system.