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.
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.
The window values can be set independently for all 3 phases. Both inner and outer window values can be defined for each phase. Error messages, such as transmitter failures, are output via the 8 relay outputs for further processing. The duration of how long an error must remain until the message is displayed can be set, as can a hysteresis. Error messages and measured values are logged in the internal measured value memory.
We have comprehensively revised our capacitor protection centre. Newly developed hardware and firmware as well as a new 7" colour touch display are concealed in the same housing.
As an alternative to the proven housing, a 19" rack mount housing with 5" colour touch display is now also available.
new functions and features
• Graphical representation of the measured values over time
• Relay output test
• internal measured value memory revised
• System relays revised
• configurable AutoDim function
• Display set without system restart
• USB interface
• SD card for storing and reading out the measured values and messages
• File format and content of the log files can be adapted to customer requirements (with SD card option)
• LAN network connection (optional)
• customer-specific adaptations of the interface transmission optionally possible