Why components age unnoticed – and how you can prevent failures with the right fire protection
Your compensation system works quietly in the background, reducing your reactive-energy costs and rarely drawing attention to itself. But when did you last really take a look inside? Because while it runs reliably, its components are ageing – and a safe system can become a risk without anyone noticing.
A compensation system – technically a reactive power compensation system – is one of the most inconspicuous items of equipment in the low-voltage network. Behind the closed cabinet door it works reliably in the background for years, and ageing and potential safety risks easily slip out of view. This article shows you, in a compact form, why this is so, how to recognise a truly safe system and how to protect your operation should the worst happen.
The silent wear: how ageing and harmonics become an invisible danger
The heart of every system is its capacitors. They supply the capacitive reactive power that offsets the inductive demand of motors and transformers – so that reactive energy is not charged and you comply with your network operator’s technical connection conditions. But capacitors are wear parts: thermal and electrical stress and frequent switching – particularly in networks with high levels of harmonics – cause their capacitance to fall over the years.
This has consequences for the entire system. To protect the capacitors from harmonics, a reactor – a coil – is connected in series ahead of them. This detuning tunes the circuit so that it does not enter resonance with the network inductances. If the capacitance falls, however, the tuning between reactor and capacitor shifts – and with it the resonant frequency. In this way, a system that was perfectly designed at commissioning can turn, unnoticed, into a latent danger over the years.
In practice, it begins quietly: the cabinet becomes noticeably warm, a step back-up fuse trips sporadically, a contactor no longer switches cleanly. What seems harmless can escalate – overloaded capacitors heat up, their insulation suffers, and without a three-phase overpressure disconnector, the worst case is a fire in the cabinet. What follows is usually more expensive than the component defect itself: unplanned downtime and consequential damage to sensitive electronics.
Note: If a capacitor loses capacitance, the tuning between reactor and capacitor changes – and the system ages, unnoticed, into a critical condition.
Safety begins with the component
Genuine safety is not created as a retrofit, but in the choice of components. KBR’s capacitors are designed for more than 250,000 operating hours at −40 to +55 °C – and they carry a three-phase overpressure disconnector within them. The term sounds cumbersome, but it refers to a simple form of protection: if the internal pressure rises in an ageing capacitor, the overpressure disconnector safely isolates the component from the network at a defined value, on all three phases, before it can burst or catch fire. This is complemented by the self-healing effect of modern power capacitors in accordance with the IEC 60831 standard, in which small internal breakdowns heal by themselves.
A temperature-controlled ventilation system counteracts overheating effectively and quietly. Add to this tested reactive power controllers that switch the individual steps precisely. The remaining components matter just as much: highly linear reactors whose inductance remains almost constant even under high load and does not go into saturation – while generating little heat of their own. When such components are type-tested and manufactured in Germany, the system remains reliable even after years of continuous operation.
Monitor instead of hope: the secureC safety concept
You cannot tell a component’s condition from the outside. This is where continuous monitoring helps; one solution is secureC. It continuously measures the current draw of each compensation step and, as a precaution, takes an excessively worn step off the network – thereby preventing precisely those resonance-related failures caused by ageing capacitors. Because it continuously recalculates the shifting resonant frequency, it detects critical conditions early.
The system also checks the step back-up fuses and contactor contacts on all three phases and detects a blown fuse just as reliably as a contactor that no longer closes or, in the worst case, no longer opens – a latent fire hazard.
Rather than dropping the entire system at the temperature threshold, intelligent temperature management scales it back step by step. For you, this means fewer surprises and greater predictability – and thanks to the many safety functions, routine maintenance by a specialist firm is not required for the first three years.
Why regular maintenance pays off
Even the best technology ages, and no electronics can replace an examining eye on site. After these first years, you should have your compensation system inspected regularly: under DIN VDE 0105-100, electrical installations must be inspected at appropriate recurring intervals; for heavily used systems, annual, professional maintenance is therefore advisable. It identifies wear in good time and replaces parts with original components before they turn into a failure. In this way, an incalculable emergency becomes a plannable investment that noticeably increases service life and availability.
If it does catch fire after all: fire protection for the worst case
All the measures so far are intended to prevent a fire. But true safety also plans for the worst case – and this is where fire protection for compensation systems comes in. An intelligent smoke detector with an extinguishing capsule detects smoke early and works together with your fire alarm system via an internal BUS system. Should the worst happen, the system automatically switches off the controller – and, if necessary, the fan.
The extinguishing agent is finely atomised and forms a glass-like layer on the surfaces that prevents reignition – with the aim of keeping electrical risks such as short circuit or electric shock to a minimum during extinguishing. In this way, a cabinet fire can be avoided or contained within seconds, before it brings an entire site to a standstill. Depending on the insurer, such an extinguishing system can also have a positive effect on your fire insurance.
Note: The safety of compensation systems is created not by a single component, but by the interplay of quality, monitoring, maintenance and fire protection.
Safety is a matter of interplay
Safety you can rely on
A compensation system saves costs and relieves your network – provided it operates safely over the long term. Only the interplay of high-quality components, intelligent monitoring, regular maintenance and effective fire protection turns a potential risk into a permanently reliable system. The good news: you neither have to guess nor shoulder it all on your own.
How much of each safety layer your system needs cannot be derived from a table, nor from gut feeling. It depends on the proportion and type of your loads, the level of harmonics, the age of the installation and the conditions inside the cabinet – two similar systems can carry a completely different level of risk. It also depends on the nature of your operation: a paper mill, sawmill or flour mill naturally carries a higher fire risk than an office building. This is precisely why an expert look at the real operating data pays off – as demonstrated by numerous reference projects and freely available white papers.
Are you planning a new system or looking to safely retrofit an existing one?
With the compensation configurator, you can put together a suitable and safe concept for yourself in just a few minutes, with no obligation.
Or: request your personal expert consultation now.
And if you would rather speak to a person straight away, KBR’s specialist advisers are happy to help.
We look forward to accompanying you on your journey to maximum energy efficiency and lasting cost savings!
Yours, Jonas Klaus
Technical Editor
KBR GmbH