23-09-2016, 08:59 AM
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1. General Description
The power factor regulator combines comprehensive operation with
user-friendly control setting. It uses numerical techniques in
computing the phase difference between the fundamentals of
current and voltage, thus precise power factor measurement is
achieved even in presence of harmonics.
The power factor regulator is designed to optimize the control of
reactive power compensation. Reactive power compensation is
achieved by measuring continuously the reactive power of the
system and then compensated by the switching of capacitor banks.
The sensitivity setting optimizes the switching speed. With the builtin
intelligent automatic switching program, the power factor
regulator further improves the switching efficiency by reducing the
number of switching operations required to achieve the desired
power factor.
Usage of the capacitor bank is evenly distributed by the intelligent
switching algorithm. This ensures uniform ageing of the capacitors
and the contactors used.
The four-quadrant operation feature allows the power factor
regulator to operate correctly in the case of active power feed back
to the mains where regenerative power sources are used.
Harmonic current in the system can be harmful to the capacitor
bank. This power factor regulator is capable of measuring the total
harmonic distortion (THD) in the system and produce an alarm if the
THD level is higher than the pre-set value. Other alarms include
under/over compensate alarm, under/over current alarm and
under/over voltage alarm.
Current transformer (CT) polarity is important in determining the
correct phase angle different between the current and voltage
hence the power factor. This power factor regulator will
automatically correct the CT polarity internally in the event that the
polarity is reversed.
2. Light indication
The regulator has a 3-digit numeric display and several light
indicators of which can be functionally divided into 3 categories:-
i. Metering functions - power factor, current & THD for current.
ii. Control parameters functions - power factor, C/K, sensitivity,
reconnection time, rated step, switching program & THD Limit.
iii. Alarm messages function.
To access the above functions, press the "MODE/SCROLL" key until
the light indicator is indicating the desired function. The 3-digit
numeric display will show the value of the selected function. If there
are sub-functions on the selected function such as the function for
"rated step" & "alarm messages", press the "UP" or "DOWN" arrow key
to access these sub-functions.
3. Metering function
3.1 Power Factor
Upon powered up, the numeric display indicates the measured
power factor of the system. If the "IND" LED lights up, it mean the
system is having inductive power factor. On the other hand, if the
"CAP" LED lights up, it means the system is having capacitive power
factor.
If the power factor regulator detects a re-generative condition where
the energy flow is reversed, the power factor display will shown a
minus sign in front of the power factor reading.
When the load current is below the operating range and the power
factor cannot be measured accurately, the numeric display will
shows "---".
If the power factor regulator has been previously set to other display
function, it will automatically return to this power factor display
function if no key is pressed for more than 3 minutes.
3.2 Current
This function display mode is indicated by the "CURRENT" light
indicator. The numeric display shows the true-rms value of the
secondary current measured by the 5A current transformer (CT).