16 Important Power Analyzer Terms

Power Analyzer

A power analyzer, also known as an energy analyzer, is an electronic device that measures single-phase or three-phase electrical energy as it flows through a circuit or is distributed through electronic or motorized equipment. Electrical measurements commonly taken with a power analyzer include volts, amps, watts, frequency, reactive power hours, maximum power, phase angles and harmonic distortion. Most modern power analyzers convert analog readings into digital form. The measurements are then sent to a screen or an LED display. Many power analyzers can also save and print measurements.

Active/Reactive Power

Active power, as measured by a power analyzer, is the actual power, also known as true power. Active power is measured in watts. Reactive power is sometimes referred to as phantom power. It is created by electronic components such as capacitors and inductors. These components draw current and cause a measurable drop in voltage, but they do not dissipate power. Reactive power is measured in volt-amps reactive (VAR). Together, active and reactive power is known as apparent power.

Crest Factor

Crest factor is the ratio of peak power to average power. It is also commonly referred to as the peak-to-average ratio (PAR). Crest factor may be expressed as a single numerical value or as a ratio.

Energy Analysis

Energy analysis is the basic function of a power analyzer. The analysis of electrical energy is conducted by taking one or more measurements of electricity that is traveling through a circuit or electronic component. The measurements performed by a power analyzer may include current, voltage, frequency, phase angles and harmonics. Energy analysis is used to determine the quality of energy and how efficiently it is being used.

Flicker Analysis

Flicker, in electrical systems, is a series of voltage fluctuations. These fluctuations are associated with the harmonics of low-quality power supplies. Flicker analysis is performed by a power analyzer and is considered an important measurement in energy analysis.

Inrush Current

When electrical equipment is turned on, the initial current that flows into the circuits is much greater than the current that flows while the device is in a steady state. Inrush current can be up to 20 times that of operating current, but it usually dissipates within 10 milliseconds. High inrush current is associated with switching power supplies, and it may cause blown fuses or electrical arcs between circuit components. Because inrush current may dissipate quickly, it can only be measured accurately by power analyzers with fast measurement time.

Output Rating

The output rating of an electrical device may refer to one of two properties. Output rating may refer to the standard force of electrical energy released by electrical equipment through an output terminal or to the maximum power an electronic device can release without components overheating or malfunctioning.

Power Factor

The power factor of electrical current flowing through a circuit is the ratio of active power, also known as true power, to apparent power. Apparent power is active power plus reactive power. When current and voltage are equal, then the power factor is 1.0.

Power Logging/Recording

Many power analyzers have the ability to save a series of power measurements. Saving power measurements as they are taken is known as power logging or power recording. It is accomplished in modern power analyzers through built-in or removable memory.

Power Quality

Power quality refers to how well electricity interacts with electrical equipment. When electricity is handled by an electrical component efficiently and without damage to the component, the power quality is high. Electrical equipment with low power quality either suffers from frequent malfunctions or becomes damaged by the electrical power during use. Power quality is an assessment made through the energy analysis performed by a power analyzer.

Single-Phase/Three-Phase Power

Electricity may be either single-phase or three-phase. Single-phase electricity has a single waveform. It may have been generated as single-phase, or it may have been converted from three-phase electricity. Three-phase electricity is usually produced by larger, commercial generators. It is produced by generators with three coils per two magnets that create three electrical waveforms that are out of phase by 120 degrees.

THD/Harmonic Analysis

Harmonic analysis of an electrical system is used to measure total harmonic distortion (THD). Electrical current can become distorted by line impedance, causing frequencies to exist that are multiples of the current’s base frequency. This is called harmonic distortion, and it most often occurs in electrical components that use non-linear loads, such as switching power supplies and variable-speed motors. Bad harmonics can cause electrical errors, overheating and other damage. THD is the ratio of the root mean square (RMS) of harmonic components to the RMS of the entire component.

TID/InterHarmonics Spectrum

Interharmonics are electrical frequencies existing in an electrical current that are not integer multiples of the basic frequency of the current. Total interharmonic distortion (TID) is the ratio of interharmonic components to all components. High interharmonics may cause voltage flicker.

Transformer Derating Factor

Transformer derating factor (TDF), also known as transformer harmonic-derating factor (THDF), is an adjustment to a transformer that can improve harmonics of the electrical current passing through it.

Transient Measurements

Transient measurements are measurements of fluctuations in electrical current that cause discontinuity of the current’s waveform.

Voltage Sags

Voltage sag is a temporary loss of power in an electrical current.