Application and Scope of FDR5-66kV Series Fully Sealed Discharge Coil

After the parallel capacitor bank installed in the substation is out of operation, it must have a discharge device to release the internal charge. For the capacitor bank that implements automatic control switching, it is even more required to release its charge below the safe voltage within the specified time. Therefore, installing dedicated discharge coils is a necessary technical safety measure for parallel capacitors in substations.

Considering the safety and reliability of parallel capacitor banks and their supporting equipment during operation, it is recommended to use a widely adopted single star wiring method for capacitor banks. The discharge coils are directly connected in parallel with each phase capacitor, and the secondary windings are connected in an open triangle shape, forming an unbalanced voltage protection circuit with the protection relay as internal protection for the capacitor. If any component inside a capacitor of any phase in the capacitor bank is damaged or faulty, it is required that the unbalanced voltage protection can detect and activate the switch to promptly disconnect the capacitor bank from the power grid. At this time, the discharge coil must have a sufficiently high accuracy level to ensure the implementation of this protection performance.

Structure and performance characteristics
1. The box adopts a fully sealed horizontal structure with vacuum drying and oil injection, ensuring reliable sealing performance and complete isolation from the outside world. Its insulation oil compensation method adopts a unique structure and advanced compensation technology. Regardless of whether it operates at the highest or lowest temperature of the environment throughout the year, the pressure inside the box always maintains a slight positive pressure (no more than 0.005Mpa at the highest and no less than 0.001Mpa at the lowest)
2. The sealing performance of the box and ceramic sleeve is reliable, and there is no need for maintenance or replacement of parts within the expected service life, ensuring no oil leakage and explosion-proof function. It is a maintenance free product.
3. Reasonable design parameters, high accuracy level [at rated frequency 0.9 times -1.3 times rated voltage and 0-100% rating]
Fixed secondary load (COS with 0.8 lag) to ensure accuracy level.
4. Excellent volt ampere characteristics (within 1.5 times the rated voltage range, the iron core shows no obvious saturation trend, ensuring reliability)
Linear degree).
5. The coverage of supporting capacitors (groups) is wide, simplifying the tedious selection work in the past

Main technical parameters of FDR5-66kV series fully sealed discharge coil

Environmental conditions for use
a、 Usage conditions: indoor and outdoor, ambient temperature;  
Class A -40 to+40 ° C
Class B -25 to+45 ° C
Class C -10 to+55 ° C
b、 Altitude not exceeding 1000m;
C、 Seismic resistance level: Under the action of an earthquake intensity of 8 degrees, it will not be damaged;
d、 Installation location: No harmful gases, vapors, or conductive or explosive dust;
e、 Maximum wind speed: 35m/s.

Connection method with capacitor (group)

Outline and installation dimension diagram

FDR5-66kV series fully sealed discharge coil