power problems | APC UPS Blog

What are Voltage Fluctuations?

A voltage fluctuation is a regular change in voltage that happen when devices or equipment requiring a higher load are used. The effects of a voltage fluctuation are similar to the effects of an undervoltage. It causes lights to flicker or glow brighter. Display screen may flicker as well. There are also some instances when electronic equipment, such as a computer, will fail to start up. In addition, voltage fluctuations can cause computer systems to lose data, while televisions or radios may experience interference. This power problem can have a significant effect on the lifespan of incandescent bulbs, since they are designed for a specific voltage.

Rural areas may experience dramatic voltage fluctuations due to the long power lines. These power lines can cause voltage to go down when power usage in the area is high. When arc furnaces, arc welding equipment or even elevators are used, they normally cause the voltage of a power distribution system to fluctuate. This situation is similar to using a shower in the second floor bathroom of a house. When someone turns on the faucet in the laundry room on the first floor, the second floor shower may run out of water.

Voltage fluctuations can be managed through the use of a voltage regulator. An uninterruptible power supply (UPS) system or power line conditioning devices can also be used in reducing the effects of this common power problem. Another way to deal with voltage fluctuations is by simply removing equipment or devices causing it from the power supply system.

References:

http://northpower.com/network/services/voltage-fluctuations

http://www.apcmedia.com/salestools/VAVR-5WKLPK/VAVR-5WKLPK_R1_EN.pdf?sdirect=true

http://www.on365.co.uk/Power__and__Cooling/Most_Common_Power_Problems.aspx

https://www.linkedin.com/pulse/6-common-power-problems-ted-ochieng-otieno-cem-?forceNoSplash=true

http://electrical-engineering-portal.com/9-most-common-power-quality-problems

http://blog.schneider-electric.com/datacenter/power-and-cooling/2013/05/28/six-types-of-power-disturbances-that-can-trip-up-your-it-systems/

What are waveform distortions?

Waveform distortions are common power problems that cause equipment to malfunction and sources of power to overload. It is an unexpected change in the waveforms of current and voltage as they pass through a device. There are five main types of waveform distortions: DC offset, harmonics, interharmonics, notching and noise.

DC offsets are instances where direct current (DC) overlaps an alternating current (AC) distribution system. This overlapping of two different types of current can cause overheating in the equipment.

Harmonics occur when some loads affect the main waveform of voltage. In this situation, the new loads prevent the waveform from reaching its highest and lowest levels. Harmonics can cause circuit breakers to trip and transformers to overheat.

Interharmonics is a condition where a signal affects the main voltage waveform. It can cause display monitors to flicker and equipment to overheat. Interharmonics can also cause communication issues.

Notching is an intermittent disturbance that can affect voltage. It normally happens when light dimmers or arc welders are being used. It results in data loss and issues with the transmission of data.

Noise is any unnecessary current or voltage affecting the waveform of the main power supply. This waveform distortion can cause data issues and equipment to malfunction.

The effects of waveform distortion can be reduced through the use of an uninterruptible power supply (UPS) and filter equipment. Line conditioners can also be used to minimize the effect of this power problem. Reducing the load used on a transformer can also help reduce waveform distortion. Relocating equipment causing this common power problem can also help prevent it from happening.

References:

http://ecmweb.com/content/voltage-waveform-distortion-causes-effects-cures

http://www.dictionaryofengineering.com/definition/waveform-distortion.html

http://www.apcmedia.com/salestools/VAVR-5WKLPK/VAVR-5WKLPK_R1_EN.pdf?sdirect=true

https://www.tripplite.com/shared/literature/White-Paper/Common-Power-Problems-and-Power-Protection-Solutions-White-Paper-EN.pdf

https://www.linkedin.com/pulse/6-common-power-problems-ted-ochieng-otieno-cem-?forceNoSplash=truehttps://www.captech.com.au/2016/05/06/common-issues-with-power-supply/

What is a Sag or Undervoltage?

A sag or an undervoltage is a temporary decrease in power lasting up to over a minute. A sag or an undervoltage typically happens whenever heavy machinery is turned on. A great amount of power is used by the heavy machinery during startup, leaving a small amount or power available for other equipment to use.

Voltage sags also happen when the main source of power is affected by natural events like lightning strikes, strong winds and power lines getting hit by falling tree branches. A sag or an undervoltage may affect equipment within 100 miles of the main power grid of a utility company.

Due to this, overheating can occur for some equipment while others may malfunction. Lights may also dim, and batteries may not be charged properly due to an undervoltage situation. An undervoltage or sag may cause a computer to lose data and systems to lock up.

In the past, the term brownout was used to describe this situation. However, its use has been discouraged by an international standards organization, the Institute of Electrical and Electronics Engineers. The term brownout is typically used for situations where the lack of power lasts for a couple of hours.

To handle undervoltages and voltage sags, you can provide heavy machinery their own circuit and avoid connecting them to the circuits used by other equipment. Automatic voltage regulators can also reduce the effects of undervoltage and voltage sags. These devices regulate the level of voltage used by specific equipment and ensure they always receive a suitable amount of power.

An uninterruptible power supply or UPS can also protect equipment from voltage sags. The batteries of these devices provide power for a specific period of time as long as the batteries are not dead. The batteries of a UPS normally last up to around 20 minutes.

References:

http://www.on365.co.uk/Power__and__Cooling/Most_Common_Power_Problems.aspx

https://www.tripplite.com/support/articles/articleid/common-power-problems

http://www.controleng.com/single-article/voltage-sags-and-what-to-do-about-them/0499ada0dfbb1d6747ee2bf3adacd2ee.html

http://www.electricalsolutions.net.au/content/electrical-distribution/article/understanding-the-most-common-power-quality-problems-897329076

http://www.powerqualityworld.com/2011/03/power-quality-basics-undervoltage.html

http://www.hersheyenergy.com/voltage_irregularities.html