Novar 1xxx KMB systems
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In an optimum case, the typical control process thus goes on like this: the fast process compensates
small power factor deviations within fractions of seconds, and that appears as a compensated
condition to the slow process, so the contactor group outputs’ states do not change. If there is a larger
deviation in power factor than corresponds to the thyristor group’s control capacity, the thyristor group
outputs’ states reach their limit (all connected or all disconnected). The slow process evaluates the
control deviation and the control time of this slow control process starts counting down. After the
countdown elapses, control intervention using output relays is carried out.
A control intervention from the slow control process is carried out in such a way that compensated
condition is achieved while about one half of the thyristor group’s compensation capacity is connected.
Under such optimum condition, the fast process is then able to respond to a change in power factor of
either polarity in the power system.
An exception is a state, when only low compensation power is necessary. When the compensation
power necessary is lower than total capacity of thyristor group sections, a control intervention by slow
control process is carried out in the way to simply reach compensated state (not considering that one
half of the thyristor group sections’ compensation capacity should be connected).
5.6 Setup
Novar1312 has two more parameters in comparison with Novar1214:
• number of capacitors in thyristor group (parameter 28)
• thyristor group control rate and reconnection delay time (parameter 29)
Parameters 2 through 4, 14, 21 through 23, 43, 44, and 46 only relate to the contactor group in
Novar1312. The other parameters are the same as in Novar1214.
A complete list of parameters is shown in Table 5.1.
5.6.1 Parameter 28 – Number of Capacitors in Thyristor Group
It is necessary to enter the number of capacitors for fast compensation connected by thyristor
switches when installing the controller.
Up to twelve capacitors for fast compensation can be connected. If using fewer capacitors, it is
necessary to connect the capacitors to outputs starting with T1 in the group (that is, the unconnected
outputs will be those with the highest ordinal numbers).
The value specified will be maintained even on controller initialization (see description further below).
5.6.2 Parameter 29 – Thyristor Group Control Rate and Reconnection Delay Time
Although lifetime of thyristor switches is not limited by number of switching operations and due to
switching at zero voltage no current spikes occur, the thyristor group control rate and reconnection
time can be specified in this parameter.
It is because in some situations, the switching rate and reconnection delay time must be adopted to
the fast-discharge resistors’ power rating (these resistors are required for proper power thyristor switch
operation if compensation capacitor overcharging takes place).
The value of the parameter is displayed as R-N
R-NR-N
R-N.N
NN
N, where
R
RR
R......... number of control interventions per second
N
NN
N.N
NN
N… reconnection delay time in seconds
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