Traditional reactive power compensation equipment with electromechanical contactors, has a well proven performance in installations where the load has, slow variations and it is not very sensitive to voltage fluctuations. Today, however, more and more industrial installations include electronic equipment very sensitive to voltage variations (PLC, computers, etc.) and also very fast changing working cycles (automatic welding machines, robots, etc.).

Reactive power compensation with static contactors offers the best answer to these new industry requirements.

LIFASA automatic capacitor banks with static contactors, use thyristors instead oftraditional contactors. The thyristors switch-on capacitors on zero crossing voltage, and switch them off on zero current situation. This firing strategy grants a totally transient free switching of power capacitors, avoiding any problem with transient overvoltages.

This transient free switching gives a very fast reaction time of the power factor equipment with sudden reactive power demand variations. This reaction time (the time to switch on or off a capacitor step) is usually not higher than 20 milliseconds. This means that up to 25 operations per second are possible.

FOR STANDARD EQUIPMENTS WITH THYRISTOR CONTACTORS OR OTHER VOLTAGES, ON REQUEST

LIFASA automatic capacitor banks with static contactors are supplied completely assembled and ready for use: it is only necessary to give them the operation signal from a suitable current transformer, and to connect them to the mains by cables of adequated section. They are composed of the following elements:

Reactive power controller
These banks use the MCE-F controllers, that are a fast response variation of the MCE series of controllers. These controllers are specially designed for the control of thyristor capacitor banks and are characterized by their optically isolated outputs and also for having an extremely fast response time that can be up to 20 milliseconds.

Control module
It is formed by an electronic control circuit, that gives the firing pulses to the thyristors to switch on at zero voltage point and to switch off at zero current situation.
The control module is assembled on a printed circuit board and receives the action signal from the MCE controller.

Power module
It is formed by three pairs of thyristors in anti-parallel connection, mounted and assembled on well dimensioned heat sinks, protection fuses and limiting inductances.

Capacitors
These banks use the six terminal versions of FMLS and FMBS series of power capacitors.

Technical Characteristics
440 V Rated voltages
50 Hz/60 Hz Rated frequency
7.5 … 960 kvar Rated power
< 0.2 W/kvar Dielectric losses
< 0.5 W/kvar Capacitors losses
1.1 Un (8h/day) Max. overvoltage
1.3 In Max. overcurrent
MCE-12 F Controllers
20 ms (typical) Switching on delay
1:1:1:1: , 1:2:2:2: y/and 1:2:4:4: Working programs
…/5A optional Current transformar
-25/+45ºC max. temp. Temperature range
IP 31 Protection degree
Indoor Installation
IEC 60831 Standards
EN 60861
IEC 60439
EN 60439
Electromechanical contactor Static contactor
Yes, up to 100 In according to IEC 60831
,in practice measured up to 200 In
No (transient free) Overcurrents during switching operations
Yes, up to 2√2  Un No (transient free) Overvoltages during switching operations
10  to  50 s 20 ms (typical) Time delay for switching
Yes No Presence of mobile electrical contacts
Typically 100.000 operations Almost unlimited Expected service life of contacts