Special type of high voltage capacitors which are part of coupling filters of Ripple Control. They are as follow:
Capacitors for C1 batteries of coupling filters
These are multi-capacity capacitors used to power regulation of distribution network transfmitter. Transmitter power needs to be change (the value of signal current emmitted to MV or HV network) according to the loading impedance of MV or HV network. This is done through contacts connecting suitable capacity of C1 battery so the required value of signal voltage would be emitted into busbars. The usual value is 1.8 per cent of 50 Hz voltage for 22 kV and 35 kV transmitters and 2.0 percent in case of 110 kV transmitters.
C1 capacitor battery is most often placed in the case of following dimensions: 600x600x2100 mm. There is enough space in this case to place all capacitors of MV Ripple Control transmitter. C1 batteries for 110 kV Ripple Control transmitters can be placed in the case of following dimensions: 1600x600x2100. Two capacitors with shunt capacitance are used for each phase.
Capacitors for C2 batteries of coupling filters
C2 batteries are used to modifying the impedance of coupling transformers for specific type of network. MV Ripple Control transmitters are using internal installation usually connecting one or two capacitors in series per phase. These capacitors shall be designed for both voltage with power freqeqncy and signal voltage.
The usage of 8 to 10 capacitors in series in two shunt rows needs to be done in case of 110 kV Ripple Control transmitters. C2 capacitor battery uses bridge connection so it could be protected in case of partial damage of capacitors. Current and voltage balance relays are used according the situation. Voltage balance relay evaluates the potential margin at the fourth or fifth capacitor (in the middle of C2 battery) while current balance relay evaluates unbalance current in shunt branch between fourth or fifth capacitor. The current transformer is located at the junction.