Why are the Measured Values for VAR and ΣVAR Unstable?

Check the Synch Source and Frequency Filter settings

  1. When a single-phase signal being measured fluctuates around power factor of 1.

    Slight fluctuations in the measured values of voltage, current, and power can cause a large instabilities in the calculation of Var (around power factor 1) and ΣVar. In this case, to stabilize the measured values of voltage, current, and power, check the sync source setting and zero cross filter setting.
  2. When a three-phase signal being measured fluctuates around a phase angle of 30 degrees.

    In the case of zero cross filter (frequency filter), three-phase three-wire, or 3V3A wiring, in the vicinity of phase angle 30°, input to the power meter is the same condition as the above single-phase measurement. For details, see The power, power factor, and phase angle of each input element do not match when measuring the balanced three-phase load. Therefore, slight fluctuations in the measured values of voltage, current, and power or instable leading/lagging detection can cause large instabilities in the calculation of Var and ΣVar.

Related Products & Solutions

Precision Power Analyzer WT3000

With 0.02% accuracy and 1MHz bandwidth, the WT3000 delivers where the highest precision measurements are required. It is the industry standard for R&D work on inverters, motor drives, lighting systems and electronic ballasts, UPS systems, aircraft power, transformer testing, and other power conversion devices.

WT1800 High Performance Power Analyzer

The WT1800 High Performance Power Analyzer from Yokogawa Test&Measurement offers maximum flexibility with up to six wattmeter elements, high bandwidths, simultaneous high speed digitizing, and wide voltage and current ranges. Although this model is still available, the newer WT1800E offers higher accuracy.

WT2010/WT2030 Digital Power Meters

The WT2000 digital powermeter series has been designed with emphasis on basic performance (bandwidth, accuracy, response speed, and noise immunity) from the viewpoint of measurement of electrical quantities. The broad range of functions of these power analyzers enable them to be used in various fields of applications.

WT500 - Mid Range

  • Power and Harmonic (THD) Measurements with Independent Range Controls
  • Efficiency measurements of AC/DC or DC/AC Inverters & Motors

 

Power Analyzers and Power Meters

Measure characteristics of devices that generate, transform or consume electricity. Also called power meters or wattmeters, these devices measure parameters such as true power (watts), power factor, harmonics, and efficiency.

Precision Making

Top