Capacitor protection


 

General

The possibility that capacitor housing will blow up through gas generation exists if short-circuited windings appear in the capacitor and the used impregnation medium may escape. In 110kV round control couplings and absorption circuits were mainly PCB containing impregnation mediums used in the past because they had the advantage of a nearly not existing flash point and that way prevent a further propagation of the accident. Because of the not excludable risks only PCB-free capacitors were used during the past years with silicon containing impregnation mediums with on the other hand have the negative advantage of a low flash point and won’t extinguish automatically with the shut down of the facility. Because of these reasons it is useful to equip new facility as well as old ones with a capacitor protection to guaranty a save and fast shut down of the facility in case of an accident and to prevent further damage.

 

Principle

The capacitor protection introduced here is based on the principal of capacitor comparison through the bridge circuit of the single capacitor blocks and the supervision of the asymmetry. The low weight and the well chosen dimensions of the measuring transmitters allow the free leading installation on the connection bolt of the capacitor case. The power supply of the transmitter is guarantied by stick through current transformers which are directly attached to the conductor rail.

 

Measuring value transmission ( Radio, KAF )

The measuring value transmission takes place either in the 433 MHz or the 868 MHz ISM- radio band. (ISM = industrial, scientific, medical) The data communication module which is connection to the control scans one transmitter module after an other in the high voltage facility and sends the information via a RS 485 port to the control. There the data will be analysed and in case of overstepping of the free selectable limit value a corresponding message is produced.

Measuring value transmission ( Infrared, KoSchutzIR )

The measuring value evaluation of the bridge voltage takes place in the high-tension plane. The selective handling of the 50 Hz signals makes sure that the supervision of the bridge differential voltage is not falsified by ripple control transmissions. The power supply takes place via bar-type current transformers which are mounted on the current rails. The measuring value of the 50 Hz voltage is being transmitted as a serial data stream by the 38 kHz modulated IR signal with Manchester-Coding and CRC check sum to the corresponding receiver.

 

 

 

Initial operation on site

We offer on-site initial operation for both versions of our capacitor protection system.
Our technicians will support you in setting up the control unit and check the alignment of the transmitter and receiver units.
We do not execute any installation work.
Talk to us!

 

Finally available: The display-extension for KoSchutz IR and KAF

It is now possible to equip the radio and IR receivers with an OLED display in response to many requests.

For easier commissioning and maintenance of the system, all data can be read directly at the receiver:

  • Presentation oft he current measured values
    • all phases at funk
    • selected phase at IR
  • level meter for signal strength
  • error messages
  • Display can be activated via push button
  • Display only when required ( increased life time )

The conversion of existing systems is partly possible – please contact us for details.