KMB NOVAR-1007 - Control Operation at the Highest Control Rate

Novar 1xxx KMB systems
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The control rate ( = number of interventions per second ) can be set in range 1 through 20
interventions per second. The reconnection delay time can be specified as shown in Table 5.2.
Note: If 10 control interventions per second are specified, “r” is displayed as 9 (for example 9-0
9-09-0
9-0.1
11
1).
Table 5.2: Thyristor group control rate and reconnection delay time setting
Control Rate
[ control interventions per second ]
Reconnection Delay Time
[ seconds ]
1 1 - 2 - 5 - 10
2 0.5 - 1 - 2.5 - 5
3 0.3 - 0.7 - 1.7 - 3.3
5 0.2 - 0.4 - 1 - 2
10 0.1 - 0.2 - 0.5 - 1
20 *) 0.0
*) real control rate depends on number of capacitors in thyristor group, see below.
Table 5.3 : Real control rate at setting of 20 control interventions per second
Thyristor Group Capacitors Number
( parameter 28 )
Real Control Rate
[ control interventions per second ]
1 ÷ 5 >= 25
6 ÷ 7 >= 20
8 ÷ 12 >= 15
When shipped and after controller initialization, the values 1-10 are set, that means one control
intervention per second and ten seconds of reconnection delay time.
5.6.2.1 Control Operation at the Highest Control Rate
At setting of the highest control rate, i.e. 20 control interventions per second, real control rate is not
fixed, but it depends on preset number of the thyristor group capacitors number ( parameter 28).
General rule is the fewer capacitors the higher rate – see Table 5.3.
Furthermore, during frequency measurement that is performed each second, control cycle delay of
approx. 30 milliseconds occurs. This delay can be eliminated by network frequency setting (
parameter 55 ) to fixed value of 50 or 60 Hz, if it is possible. At such setting the controller doesn’t
measure the frequency and therefore no delay occurs. Measured frequency value is undefined.