The dangers of software viruses and their devastating impact on computers are well documented. These rogue programs enter a system unseen, often incubate quietly and come to life with results that range from annoying to disastrous. Electrical disturbances are similar, and could reasonably be called ‘power viruses’ since they too are unseen and can cause expensive electronic system failure.
A typical facility experiences as many as 6,000+ power viruses a year. Some of these disturbances are obvious, some less so, many are almost unnoticeable, but they all cause problems that can seriously damage productivity, from lost data to hardware failures.
Power viruses are contracted in much the same way as other viruses – passed along, often by your system’s electrical neighbours. Some take time to cause noticeable damage; others are immediately catastrophic, such as a lightning strike. But how do power viruses affect an electronic system, and what can you do to prevent them? First understand them, so you can immunize a system against their harmful effects.
The six main power viruses:
1. Voltage Spikes and Impulses
Voltage spikes and impulses are mostly the result of electrical equipment inside a facility. Electrical loads like elevators, motors and relays can cause sudden large increases in voltage inside the electrical system. Conditions outside a facility can be to blame as well – switching activities by the electricity utility and lightning strikes can cause transient impulses that ‘blow up’ sensitive micro-circuitry.
This virus is deadly to electronic systems – but not always immediately. Sometimes voltage spikes and impulses are relatively small, the virus then weakens components over time leading to deterioration and failure. Sometimes the impulses are large enough to cause immediate system failure.
2. Electrical Noise
Electrical Noise is generally created inside a facility by the system’s electrical neighbours, eg photocopiers, printers, electronic lighting ballasts and even computers are all noise sources that can cause computers to lock up and lose data.
3. Common Mode Voltage Problems
Common mode voltage problems are characterised by unwanted voltage measured between neutral and ground in the electrical system. It is probably the most serious power virus infecting electronic systems today, occurring as a result of high impedance safety grounds, neutral conductors shared with other circuits and branch circuit lengths that are excessive.
When the electrical noise virus appears between the neutral and ground conductors it becomes a common mode virus that causes lost files, system lock-ups or re-boots, communication errors and ‘no problem found’ service calls.
4. Voltage Regulation
Voltage regulation is typically caused by large loads turning on and off and overloaded branch circuits or distribution transformers. In some cases, these viruses can be the responsibility of the power utility. If an electronic system requires tightly regulated voltage (most of today’s systems don’t) the voltage regulation virus is likely to cause system lock-ups and unreliable operation in addition to damaged/destroyed components.
Blackouts are the most visible and easily identifiable, they have the most obvious cause and effect relationship. One moment power is present, the next it’s not. The effects of unanticipated power loss are obvious. This is especially true if the system is a network or some other ‘fault intolerant’ architecture. Blackouts account for comparatively few occurrences of power viruses.
6. Back Door Disturbances
Back door disturbances infect your system via a secondary path. Even though they are not an AC power connection, things like serial ports, telephone lines, network cabling and I/O connections can all enable power viruses to invisibly enter a system. This virus causes driver chip failure and communication errors and is often unrecognised. Without treatment, serious damage and lost productivity occurs.
An Ounce of Prevention
‘An ounce of prevention is worth a pound of cure’ and nothing could be closer to the truth when it comes to power viruses. With computers we’ve learned to practice ‘safe computing’ – we back up data, install firewalls and take other preventative measures. So why don’t we practice safe computing where power viruses are concerned?
If there is a magic pill to prevent power viruses, it’s that prevention must be practiced as a ‘system’, which means that certain prevention techniques must be used together.
For example, voltage spikes are addressed with a surge diverter and electrical noise with a noise filter. By themselves, they are capable only of weakening or slowing down a virus not eliminating it. Isolation transformers eliminate common mode voltage problems. When surge diverters and noise filters are added to the isolation transformer, the resulting ‘system’ kills all three viruses.
UPSs eliminate blackouts, but despite claims, cannot prevent other viruses. A UPS must be used with the other parts of the system to achieve total virus immunity. The backdoor disturbance can be addressed several ways.
Luckily, the voltage regulation virus is no longer a serious hazard, as today’s systems use switch mode power supplies, designed to reduce both power supply size and cost while increasing electrical efficiency.
Power viruses are an appropriate description of the power quality problems that can plague electronic systems. Like other viruses, they are invisible, often announcing their presence only after some initial damage. The effects can range from minor annoyance to catastrophic.
But our dependence on sophisticated technology has created an increased awareness regarding the need to safeguard system integrity, and this ‘safe computing’ approach should incorporate the prevention of power viruses too.