B
Selection of asymmetrical Switching Time Delay.
Rapidly changing reactive loads can cause excessive wear on contactors ( eg Arc Welders, Crushers or
Strip Mills). In this case it is useful to use assymetrical switching of FAST IN/SLOW OUT. The ratio is set
using the + - buttons. If we have
"1"
(Factory setting) we have equal times for switch in and switch out , as
selected in pos. 2. By selecting any number between 1…..99 we can vary the switch out time up to 99 times
the switch in time. i.e. if we set to "10" (display
Y_10
) and have selected a switch time of 5 secs., in Pos
2, we switch in after 5 secs of lagging kvar demand, but only switch out after the leading kvar has exceeded
the threshold for 5 x 20 secs + Lock out time (see Pos C). If it is required that the switch out time is
quicker than the switch in time (reversal of the above situation) this can be achieved but must be ordered
when the relay is built.
C
Selection of Lock Out Time at each Change of Switching Direction
This position allows adjustment of the lock out time on load reversal and on initial energising. If we set to
L_30
we have 30 secs lock out time, in addition to the time selected in Pos. 2. This will operate each time
we have load reversal, thus helping to reduce contactor wear. The lock out time is adjustable from 1…254
sec.;
Factory setting = 30 secs ( "L_30")
D
Selection of C.T.Ratio .
This is only applicable for CXM relays. Please see the section of these instructions
“CXM Multi-Meter version”
On the CX relay the display will be non-operative in this position and will show
"_
not
"
E
Selection of V.T. Ratio
This is only applicable on CXM relays. Please see the section of these instructions
CXM Multi-Meter version
On the CX relay the display will be non-operative and will show "_not"
F Selection of Switching Program.
The switching programs are selected using the + - buttons:
"Auto" -
Fully automatic self selection of capacitor steps in order to achieve the required power factor with
no pre-determined switching sequence. Relay voltage measurement L2-L3
"1 1 1 1"
: Sequential switching in/out with fully automatic recognition of each capacitor size.
This program could be selected for
tuned filter banks
where it is essential that each tuned step is
switched sequentially.
"Eaut"
: identical to
"Auto"
, but for
single phase operation, with relay measurement voltage taken from
L1-N
"E111"
: identical to
"1111"
, but for
single phase operation with relay measurement voltage taken L1-
Factory Setting
"Auto"
Commissioning
1
Apply the supply, measurement and control voltages. Connect the current transformer, and remove any
short circuit link. Make sure the Current Transformer is positioned so as to measure the total current of the
system including the capacitor bank current. On a 3 phase system the measured voltage L2-L3 must always
be taken from the two phases on which the CT is not mounted, i.e. if the CT is on L1, voltage supply
must be from L2-L3.If a change must be made on site it is preferable to change the voltage connections
rather than the CT so as to avoid the risk of an open circuit CT.
If the supply is single phase, the appropriate setting must be selected on "F" of the function switch with
measured voltage connections (L2-L3) changed to single phase.
Indication "I—O" : No current or less than 10mA is flowing in the CT circuit.
If capacitor steps are energised, they will be automatically disconnected after 5 minutes. If the relay
is in manual mode, (Pos.4) the steps will stay in circuit.
Indication "U—0" measuring voltage is below 50 V or not connected.
The relay will start to control if the measured voltage (L2-L3) is at 50 volts or above, and the reactive
component of the measured current is 10mA or above.
If the measured voltage falls below 50V, energized steps will be switched off after a 2 sec time delay in
both automatic and manual mode.
2 Factory Settings of Function Switch
Power factor target = 1 C.T. Ratio = 100
Step switch time = 60 secs V.T. Ratio = 1
Step limit switch = Max of controller Switch Mode = Auto
Changes can be made using the function switch, but remember any changes
will only be stored in the
memory when the function switch is put in pos. 3
after the change has been made.
4
