FDE High Altitude Outdoor Oil Immersed Discharge Coil

Product Overview

The FDE high altitude outdoor oil immersed discharge coil is a single-phase tank-type unit designed for AC power systems at 50Hz/60Hz, specifically engineered for capacitor bank installations at altitudes up to 5000 m above sea level. Connected in parallel with the high-voltage shunt capacitor bank, it provides a defined discharge path that reduces residual voltage to safe levels within five seconds when the capacitor group is disconnected from the system.

At high altitude, air density decreases, making external insulation withstand and heat dissipation more challenging than at sea level. This version addresses these challenges with reinforced external insulation: outdoor porcelain bushings with enlarged creepage distance and increased air clearances, combined with an oil-filled sealed steel tank that provides internal insulation and thermal management.

Key Features:

High altitude design rated for sites up to 5000m above sea level
Rated voltage ratio 11/√3:0.1/√3:0.1/√3 kV with 4.0 Mvar capacity
Sealed steel tank with reinforced outdoor porcelain bushings in V array
Secondary winding for voltage indication with 3P and 6P relay protection
Ambient -40°C to +40°C, rated insulation level 12/42/75 kV, 4 Mvar duty
Conforms to DLT653-2009 standard and specific customer technical demands

Product Display

FDE High Altitude Outdoor Oil Immersed Discharge Coil poster 02

Service Conditions

Installation: Outdoor type
Ambient Temperature: -40°C to +40°C
Altitude: Not more than 5000m (high altitude version)
System Frequency: 50Hz / 60Hz
Insulation Medium: Mineral oil in sealed steel tank
Atmosphere: No corrosive gas; no conducting or explosive dust

Construction

The FDE discharge coil features a gasketed sealed steel tank filled with mineral oil, which serves as both the insulation medium and the cooling medium, providing strong lightning-impulse withstand capability. The core and windings are assembled inside this tank, with primary terminals brought out through two bushings inclined at 19° each in a V arrangement.

Construction Advantages: Reinforced porcelain bushings with longer creepage paths for high altitude service, 2-M12 top terminal connection with increased air clearance, oil filling port and pressure relief valve on tank cover, earthing bolt on tank wall, separate secondary terminal box, and lifting lugs for handling, total weight approximately 84 kg.

Technical Data

Type	Rated Voltage Ratio (kV)	Accuracy Class & Rated Output (VA)	Rated Insulation Level (kV)	Discharge Capacity (Mvar)
FDE-11/√3-4.0-1W	11/√3:0.1/√3:0.1/√3	0.5/3P-50/100; 0.5/6P-50/100	12/42/75	4 / <5s

Type

Rated

Voltage

Ratio (kV)

Accuracy Class

& Rated

Output (VA)

Rated

Insulation

Level (kV)

Discharge

Capacity

(Mvar)

FDE-11/√3-4.0-1W

11/√3:0.1/√3:0.1/√3

0.5/3P-50/100; 0.5/6P-50/100

12/42/75

4 / <5s

Technical Note: If the user’s data go beyond the above-mentioned scopes, they may be subject to an agreement between manufacturer and purchaser. Voltage ratio, secondary configuration (3P/6P), rated output and altitude rating can be customized upon technical agreement; final parameters are subject to nameplate data and approved specifications.

Standards

The FDE series conforms to the DLT653-2009 standard and can be built to special customer demands. The rated frequency is 50Hz/60Hz with a rated insulation level of 12/42/75 kV.

Note: Final standard and test requirements shall be confirmed according to the project specification.

Installation & Dimensions

The FDE discharge coil stands on a flat foundation with the tank base level. Allow clearance around the tank for the reinforced bushing creepage distances and for access to the secondary terminal box and the pressure relief valve. Primary bushings connect to the capacitor bank neutral point and the busbar; the tank is connected to the earthing grid through the earthing bolt. At high altitude sites, maintain the specified air clearances to grounded structures, since thinner air lowers the external insulation withstand of bare gaps.

Installation Diagram

Installation and Dimensions

Wiring Diagram

The primary winding is connected between the bank neutral and earth as shown in the wiring diagram. The 3P/6P secondary windings supply voltage indication and residual-voltage protection circuits, with the open-delta (da/dn) terminals feeding the protection relay. Confirm terminal markings, polarity and earthing against the approved wiring drawing before energization.

Key Outline Dimensions: Overall height 750 mm (primary bushings included), primary bushings inclined 19°+19° in V arrangement with 2-M12 top terminal, bushing center span 360 mm, tank width 340 mm (front view), side base 360 mm with bushing offset 100 mm, cover outline 400 mm × 360 mm with 325 mm between bushing flange centres, mounting holes 215 mm spacing with 13 mm wide slots (4 off, M10), M8 earthing bolt on tank wall, oil filling port and pressure relief valve on cover, nameplate on tank wall, weight approximately 84 kg.

FAQs

FD = discharge coil, E = with secondary winding, 11/√3 = rated primary voltage in kV, 4.0 = maximum matched capacitor capacity in Mvar, 1 = single phase, W = outdoor device.

Both are single-phase outdoor oil-immersed units with the same 11/√3 kV ratio and 12/42/75 kV insulation level. The high altitude version is rated for sites up to 5000 m instead of 3000 m, uses reinforced external insulation with longer bushing creepage and larger air clearances, matches a 4.0 Mvar bank instead of 1.7 Mvar, and is physically larger at about 84 kg against about 47 kg.

The 4.0 in the type designation is the matched capacitor bank capacity in Mvar, and the discharge capacity in the table is the corresponding 4 Mvar discharge duty within five seconds, so the two figures agree for this model.

Choose 3P when the secondary winding is needed for voltage indication plus an open-delta residual-voltage protection supply. Choose 6P when the protection scheme also needs the third harmonic or a more complete residual voltage signal on the bank neutral side. Both are accuracy class 0.5 with 50/100VA rated output.

Yes, one coil per phase, three units in total. If you prefer a single three-phase common-tank unit instead, look at the FDGEC Outdoor Three-Phase Oil Immersed Discharge Coil, which is built for 35 kV class double-section banks.

Please state the system rated voltage and frequency, the capacitor bank capacity and connection method, the actual installation altitude, the number of secondary windings with accuracy class and rated output, and any special environmental conditions such as severe cold, salt mist or seismic requirements.