Digital Capacitor Switching Modules

Digital Capacitor Switching Modules

Dynamic Power Factor Correction systems are used to optimize the power factor and reduce the level of harmonics in the grid, The usage of certain new technologies in today's day industry has negative impacts on electric power quality i.e. frequent high load fluctuations and harmonics oscillations. Excessive voltages, increased losses and flickering affects the supply capacity but has a great impact on the operation of sensitive electronic devices.

This module has thyristor switched capacitor with high speed switching ability to correct the power factor of connected loads. Control signals are directly given to capacitor banks from the connected load hence the delay is minimum. Every capacitor bank branch has a capacitor and reactor connected in series which is tuned at frequency below the lowest harmonic frequency present in the system.

  • High PIV thyristors used (2200V and above).
  • Response time < 10 ms.
  • Intelligentce provided in the microcontroller
  • Available in 10, 25, 40, 50, 100, 200 kvar ratings.
  • Fast thyristor switching with no delay.
  • Pulse transformer triggering.
  • No neutral required for delta connection
  • Very low maintenance required.
  • Zero noise level on switching.
  • Compact module.
  • Can be used in dynamic power factor correction systems.
  • For capacitive loads up to 690 V line voltage

Type selection guide:

Type S2DAC-660-D-20 S2DAC-660-D-25 S2DAC-660-D-40 S2DAC-660-D-50 S2DAC-660-D-100 S2DAC-660-D-125 S2DAC-660-D-150 S2DAC-660-D-200
Kvar rating 20 25 40 50 75-100 125 150 200
Nominal current 116 A 130 A 181 A 145 A 145 A 145 A 145 A 145 A
Maximum continuous current 180 A 300 A 300 A 193 A 193 A 193 A 193 A 193 A

Protection methods

  • Reactors: In dynamic systems fast discharge reactors must not be used
  • Fuses: Thyristor modules have to be protected using semiconductor fuses.
  • Bleeder resistors: bleeder resistors must be used for discharging of capacitors.
  • Warning signals: Due to special switching the PFC module are fully loaded even when a particular branch has been switched off. Protection against contact must be ensured and warning signals must be included in the system.

Cautions / warnings

  • The module must not be subjected to uncontrolled high current and voltages in case of any failure
  • The module must be protected against moisture and dust, sufficient cooling must be ensured.
  • Electronic switches cannot be isolated even in switched off condition therefore parts of systems must not be touched after complete system is switched off before the capacitors completely discharge.