7 and make the electricity costs consumption becomes expensive [7]. Besides the
disadvantages, there are advantages of power factor when it became higher, the advantages described in the following section.
By improving the power factor, the user can get advantages of it. The advantages of higher power factor are improving voltage level, reduced line losses; reduce electrical
system capacity [5]. In addition, the effective capacity will increase due to higher power factor [7]
The power factor can be corrected or improved by adding the capacitive or inductive loads. In other words, power factor can be corrected by adding the capacitor and
inductor [10], it is called as power factor correction and have been describes in the following section.
2.2.2 Power Factor Correction
Low power factor basically is influenced by reactive load [18]. Load is containing the elements of inductive or capacitive in the circuit such as motors and lighting. Low
power factor also cause by harmonic currents, this type of current is present in the load system and reflected back into system, but not in voltage. This harmonic current does not
affect anything to the power supply system but it will lower the power factor [17]. Only load that purely resistive will not introduce harmonic currents such as heater and
incandescent lamps.
By reducing the effects of reactive power, the power factor wills closer to unity and it is the aim of power factor correction on this study. Reactive power is divided to two
types which are inductive and capacitive. The function of inductive load is to store energy in a magnetic field meanwhile the function of capacitive load is to store energy in magnetic
charge [12]. Waveforms of voltage and current for purely inductive and purely capacitive are presented in Table 2.1.
8 Table 2.1: Waveform of Voltage and Current for Purely Inductive and Purely Capacitive
Purely Inductive Purely Capacitive
Current lag Voltage by 90° or Voltage lead current by 90°
Voltage lag Current by 90° or Current lead voltage by 90°
Phasor diagram Phasor diagram
Power factor correction is expect to have a value of apparent power
S
, closes to the real power
P
so that the excessive current drawn from the supply can be reduced. This can be done by placing reactance of opposite type in parallel to the load so that the positive
reactive power
Q
can be cancelled by the negative reactive power
Q
and vice versa [3]. The reactive power
Q
is energy in the system that is stored in the magnetic fields and its unit kilo volt-ampere reactive kVAR. Reactive power also has been known as imaginary
power or phantom power [12]. Figure 2.1 shows the concept of power factor correction in the electric power system.
9 Figure 2.1: Power Factor Correction Concept
If the power factor can be reduced, then it is proved the effectiveness of ESD and it gives benefits when the consumers installed the ESD in their houses. The assessment
method for the power factor has been described in the following sections.
Power factor is related to the current amperes and voltage volts of the power system. A circuit can operate in 100 efficiency, which means the power factor is exactly
1.0. When the power factor drops below 1.0, the utility must generate more than its minimum power supply to the circuit. If the power factor drops, it is needed to correct or
improve, so it can reduce the consumption and create efficiency system [6]. In order to make the power factor correction, the power factor must be measured.
2.2.3 Assessment Method for Power Factor
