Power Quality

Power Factor Correction

Power factor is a measure of how effectively your equipment converts electric current from the hyrdro system to useful power output, such as heat, light or mechanical motion. Low power factor costs you money.

There are two kinds of power:

• Usable power called kilowatts (kW)
• Reactive power called kilovar (kVar)

The ratio of your usable power consumption to your reactive power consumption determines your power factor. Some electrical equipment, such as motors and transformers, require both types of power. Power factor gets smaller as reactive power increases in comparison to usable power.

Transients, Spikes, Surges

Transients or spikes, also referred to as transient spikes, are brief periods of extreme voltage in an electrical system resulting from adverse system conditions ranging from crossed transmission lines to lightning strikes to switching faults originating at a distribution facility. A strong or prolonged spike can instantly destroy a wide range of electronic equipment, and even frequent spikes of less extreme voltage can cause accelerated deterioration of electronic components. Harmful transients can be short enough that they are measured in millionths of a second, although they could last as long as several seconds depending on the cause and severity. A spike from a lightning strike could last for up to a second and elevate system voltage from several hundred to several thousand volts. A spike from a switching fault could produce tens of thousands of volts of pressure for only a few millionths of a second.

Large transients can cause damage to sensitive equipment immediately, however a more common problem is repetative small transients doing damage to equipment over a period of time. Transient Voltage Surge Suppressors (TVSS) are the most common protection method from transients and spikes.

Sags, Brownouts, Blackouts

Sag is a reduction of AC Voltage at a given frequency for the duration of 0.5 cycles to 1 minute’s time. Sags are usually caused by system faults, and are also often the result of switching loads with heavy start up current.

Undervoltages are the result of long term problems that create sags, and are commonly referred to as brownouts. Blackouts are the total removal of power from your systems.

The most common approach to sags, brownouts, and blackouts is to install Dynamic Sag Correction (DySC), or Uninterruptible Power Supplies (UPS') at critical machines, or to install them facility wide. Due to the limited nature of batteries in a UPS system, standby generators can also be used for longer term outages.