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Technical Documentation
Rev. 01
Power Factor Regulator
BLR-Q(U)
Page 20 of 39
Regulation mode normal algorithm:
4 different regulation modes are available at BLR-Q(U) for standard
cos phi control, in voltage control this settings does not work:
1.
Auto:
The controller is working with the principle of „Best Fit“. Before a switching operation, all ca-
pacitor-sizes in step database are compared with control deviation. The available step which gives
the best results will be switched.
2. LIFO:
“Last In, First Out” The controller starts with regulation with step 1 and is switching further ex-
its step-by-step. Switching-off is done vice versa.
3. Combined Filter:
Special algorithm for combined filter banks with two different detuned ratings. The
controller is working like in automatic mode with the principle “Best Fit”. From odd numbered steps,
there is at least or more of the capacitance connected as from even numbered steps.
4. Progressive:
Similar to
Auto
mode. When control deviation is bigger as the biggest available step,
the all further steps are switched in intervals of two seconds. If the setting of switch interval is less
two seconds, all further steps are switched in intervals of one second.
Sensitivity:
(switching threshold) Sensitivity is the switching threshold for switching-on or switching-off the
capacitors in percent (%). The range of the sensitivity can be between 55% and 100% (factory setting is
60%. Due to this, the in following explanation 60% is used.).
Sensitivity is used for two checks:
1. The controller is using sensitivity to check, if a switching operation is necessary or if it’s possible.
If the demand for compensation is bigger as 60% of the smallest for regulation available step, BLR-
Q(U) is selecting from step database, if there are suitable steps to switch.
2. To avoid hunting, the controller is only using steps, which will not overshoot more than 40% (100%-
60%) of its size.
Step exchange:
Step exchange is supporting automatic control and combined filter control algorithm to
reach an optimum result. If the controller detects that target-pf is not reached it starts searching for a step
which gives better results. If step exchange is active, the controller can replace a switched-in step against a
step which matches better, to reach the target.
Switch cycle balancing:
Switch cycle balancing is taking care that steps with similar sizes (tolerance can be
programmed in percent) are used in a way, that they have the same number of switch cycles. At selection of
suitable step for next switching operation, the values of switch cycles, which are saved in step database, are
compared. A balanced attrition of contactors and capacitors is assured by this.