Development of a cost-effective op-amp based digital power factor meter
Conventional power factor meter uses analogue system to read the power factor of an AC electric power system which is defined as the ratio of the real power to the apparent power. In the modern life, an easy-captured data yet cost effective power factor measurement device is vital in the electrical...
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| Main Authors: | , , |
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| Format: | Conference or Workshop Item |
| Published: |
2007
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/4156/ http://eprints.uthm.edu.my/4156/1/B.C._Kok%2C.pdf |
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| Summary: | Conventional power factor meter uses analogue
system to read the power factor of an AC electric power system
which is defined as the ratio of the real power to the apparent
power. In the modern life, an easy-captured data yet cost
effective power factor measurement device is vital in the
electrical power engineering studies. The unstable reading of
the analogue based power factor meter especially in the
disturbance situations emerged the development of digital
based power factor meter (PFM) to replace the conventional
electro-dynamic types. The major advantage of using the
digital based PFM is the data read by the meter can be stored
easily for other applications or studies. This paper presents the
development of a cost effective digital PFM which is based on
an analogue-to-digital converter (ADC) provided with
ratiometric facilities. Generally, the digital power factor meter
consists of four main parts which are power supply, inputs
circuit, signal processing, and the display part. A signal
proportional to the peak voltage (Vm) is applied to the
reference input voltage of the ADC, while another signal
proportional to the product of the peak voltage (Vm) and
power factor is applied to the analogue input. Both signals are
processed through various operational amplifier based circuits
such as averager, zero detector, and differentiator. The
developed digital PFM has been tested and performed for
single phase laboratory measurements with three decimal
digits display on a liquid crystal display (LCD) unit. The
results achieved validate the functionality of the developed
digital PFM. |
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