CHINT JKF8 Series User Instructions page 10

JKF8 SeriesSmart Low-Voltage Reactive Power Compensation Controller
No.
Faults
Load equipment is
turned on, but the
1 controller still
displays
undercurrent "≡1"
Sometimes the
controller
2
displays"≡0"
Controller always
displays "≡U"
3
or voltage value
The displayed
power factor keeps
changing, or the
leading and
4
lagging indicator
keep switching.
After adding
capacitors, the
power factor
5
remains almost
the same.
No matter what
load, the controller
always displays
leading, the power
6
factor is negative,
and the system
does not operate
automatically.
Capacitor
switching is too
7
frequent
The displayed
power factor is
lower than 0.90,
8
but no capacitor
is added
automatically.
The controller
displays garbage
characters or the
9
controller is
crashed.
Table 5 Analysis and troubleshooting of faults
Cause analysis
1. The sampling current is smaller than
150ｍA or the secondar y circuit of the
current transformer is open;
2. Fault exists in the current transformer
or the controller.
Current transformer sampling current is
bigger than 6.0A, which means the
selected sampling current transformer
ratio is too small.
1. Under voltage or over voltage alarm,
display this code;
2. Product fault
1. Load is relatively low and sampling
current is smaller than 200mA;
2. Caused by frequent load change,
such as electric welding machine,
spot-welder, rolling mill, pressing machine,
hauling equipment;
3. Electrical load is not stable; transformer
load rate is relatively low.
The installation position of the current
transformer is wrong; the primar y current
is not included in the cabinet.
1. Wrong sampling phase sequence, such
as phase A for current, and phase AB for
voltage;
2. There is equipment such as frequency
converter or rectifier installed at load
end, which causes harmonic interference.
1. Fast change of load current, the set
delay time is shorter than 10s;
2. The set target power factor is too low;
3. The set reactive power threshold is
too low.
1. Load is relatively low, the required
reactive power Qs is smaller than set
value of F-1 reactive power threshold;
2. The set transformer ratio is too small.
1. Abnormalities such as lightning strike;
2. Electromagnetic interference。
1. Check if the secondar y circuit of the
sampling current transformer is open;
2. If the measured IS1 and IS2 sampling
currents are bigger than 200ｍA,
replace the controller.
Select CT based on the primar y current
of current transformer is larger than
load current.
Test voltage before increasing set
over voltage threshold. If the increase
is invalid, replace the product.
1. Turn on motor load and obser ve the
display of the controller ;
2. Select dynamic reactive power
compensation equipment for fast
changing load;3. Select controller
that uses non-isometric optimal
switching, such as NWK1-GR liquid
cr ystal controller.
Take total current: sampling current
=load current + capacitor current,
which means the primar y line of the
cabinet is connected after the
sampling transformer.
1. Determine sampling phase
sequence according to 7.3.4;
2. Select NWK1-GR liquid cr ystal
controller with stronger anti-
harmonic interference capability.
1. The set delay time is longer than
30s;
2. Increase target power factor ;
3. Increase reactive power threshold
properly.
1. Recommend to replace with 2
groups of capacitors with smaller
capacity;
2. Set transformer ratio correctly;
Disconnect the power and restart the
machine. If the problem occurs
repeatedly, replace the product.
08
Solutions