Understanding Capacitor Banks: Uses, Benefits and Failure Causes

Capacitor banks play an important role in electrical engineering and power system design, so what are they? Essentially, a capacitor bank is a device used to store electrical energy in the form of an electrostatic field. Although designs and layouts vary, all capacitor banks are composed of a ‘bank’ of several capacitors connected together in series or in parallel. Capacitor banks can be used for voltage regulation, harmonic filtering, and surge suppression – let’s take a closer look at these critical devices and how they are used in industry.

A capacitor bank

Uses and Benefits of Capacitor Banks

The primary purpose of a capacitor bank is to reduce the amount of electricity lost due to inductive reactance, which occurs when an alternating current (AC) passes through an inductor such as a transformer or motor. Connecting the capacitor bank across the line helps absorb part of the reactive power drawn by these loads, resulting in improved power factor and therefore better efficiency in your power system.

By reducing the circulating current caused by inductive loads within a circuit, capacitor banks increase efficiency, decrease energy costs, and extend the life span of electrical systems and substations. Furthermore, capacitor banks are necessary for compensating reactive power in order to steady voltage fluctuations within a power system. As such, careful installation and management of capacitor banks is essential for optimising the performance of both commercial and industrial power management systems.

Causes of Capacitor Bank Failures

Although capacitor banks are incredibly useful tools for improving efficiency and reducing losses, they can also fail if not properly maintained or installed correctly. Common causes of failure and unscheduled downtime include:

  • Resonance between the capacitors and other components on the line;
  • Poor maintenance leading to overheating;
  • Unexpected load changes that cause excessive current flow; and
  • Harmonics caused by non-linear loads like computers or LED lighting systems.

All these issues need to be monitored regularly for your system to remain efficient and safe from damage caused by faulty capacitors.

New Technology Developments in Capacitor Banks

New developments are being made all the time when it comes to capacitor bank technology and the way the devices are deployed within commercial and industrial power systems. For example, with controlled switching techniques now available, you can switch off particular sections within the bank without having to turn off the entire unit – this helps reduce wear-and-tear on individual components as well as lowering the energy costs associated with powering up a full bank again after every switch-off event.

The same control strategies can also minimise the risk of inrush currents during energisation, so that your system remains safe even when it’s powered up again after long periods without use. Meanwhile, better sub-cycle control of the electrical current reduces the risk of voltage deviation and other disruptions, ultimately resulting in greater quality and predictability in newer capacitor bank devices. These new technologies give operators greater flexibility when dealing with difficult applications, making it easier to maintain electrical stability under a variety of different conditions.

Find Out More

Knowing what capacitor banks are used for and how they work can help you make sure your electrical power system runs as efficiently as possible while avoiding costly failures due to improper installation or maintenance practices. To find out more about how best to implement capacitor banks within your system, and how EPS can help, please call +44 (0) 1642 987 240 today.

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