Electronic systems have become central to virtually every aspect of our lives from PCs and building management systems in the office to automated petrol pumps and barcode scanners at the supermarket.

The ever-changing pace of technological development, and especially the headlong quest for miniaturization, has created the scenario where increasingly lightning sensitive systems are placed at the core of our society.

Both the treat of damage to vital electronic systems, and the seriousness of the consequences of that damage, is more real than ever before.

Most modern electronic systems are at risk:

• Computers
• Data communication networks
• Building management systems
• PABX telephone exchanges
• CCTV equipment
• Fire and burglar alarms
• Telecom base stations
• Uninterruptible power supplies (UPSs)
• Programmable logic controllers (PLCs)
• Plant sensors
• Telemetry and data acquisition equipment

Loss of these systems would cripple industrial, commercial and government organizations alike.

The importance of electronic systems protection, often referred to as surge protection, is now defined in many standards, including BS EN/IEC 62305 and BS 7671.

Indeed, BS EN/IEC 62305 requires integrated structural and surge protection. In effect structural lightning protection can no longer be considered in isolation to protection of electronic systems.

Surges (Transient overvoltages)

The main risk to internal systems is through surge (transient overvoltages) – large, very brief and potentially destructive increases in voltage within the electrical system.

Surge (transient overvoltages) can be caused by:

• The secondary effects of lightning strikes (either between clouds or to ground) from a kilometer or more, away, from lightning energy induced on to above or below ground power, data and signal lines.
• The electrical switching of large inductive loads (such as motors, transformers and electrical drives), or capacitive loads (such as power factor correction)

Devastating effects

Surge (transient overvoltages) can cause magnitudes of up to 6000 Volts in a well-insulated 230/400 V power distribution system, over eight times the level tolerated by many electronic systems.

Although lasting only thousandths or millionths of a second, without protection they can devastate modern electronic systems:

• Disrupting system operations, through data loss, data and software corruption and unexplained crashes
• Degrading equipment components and circuitry, shortening equipment lifetime and increasing failures
• Destroy components, circuit boards and I/O cards
• Causing costly and unnecessary system downtime.

Protection benefits

Effective Electronic Systems (Surge) protection can provide 

• Lost or destroyed data
• Equipment damage
• Repair work – especially costly for remote or unmanned installations
• The high cost of extended stoppages – sales lost to competitors, lost production, deterioration or spoilage of work in progress
• Loss of essential services – fire alarm, security systems, building management systems
• Health and safety hazards caused by plant instability, after loss of control
• Fire risks and electric shock hazards

Effective protection is achieved through installation of coordinated set of Surge Protection Devices (SPDs), covering incoming/outgoing mains and data lines and protecting sensitive and critical electronic systems from damage.

Victor Oyedu, FNSE, FNIEEE, CPQ.
Power Quality and Energy Management Specialist.
Publisher at Afrienergyonline.com & CEO, FullSpectrum Energy Solutions Limited, Nigeria.