Capacitive Voltage Transformer ECF

Voltage transformers type ECF are used in high voltage networks within the 72-550 kV range. They transform high voltage into standardised values for meters, measuring and protection devices.

Single Stage Oil Paper Insulated Capacitive Voltage Transformer ECF CVT, Instrument Transformer

The capacitive voltage transformer consists of one condenser unit and one electromagnetic measuring unit (EMU). The condenser unit is located in the insulator and consists of one capacitive mixed dielectric which is impregnated with insulation liquid. This active part is hermetically sealed to the outside. For volume compensation of the oil there is a stainless steel expansion bellows in the head section. The operating pressure can be visualized via a monitoring unit. Depending on customer specification, creepage distance or voltage level, the condenser unit consists of up to 3 parts. In order to avoid field distortions, a shielding electrode is used from a voltage level of 420 kv. A high-grade composite or porcelain insulator can be used as insulator. According to the contamination classes of common standards, different creepage distances can be selected.

The EMu is an inductive intermediate voltage transformer which is housed in the foot case of the transformer. It allows the safe transmission of measurement signals. A damping unit ensures increased safety against relaxation oscillation. By using proven materials the voltage transformer is temperature- and accuracy stable over the entire service life. On request, the voltage transformer can be designed in such a way that it can be used as a coupling capacitor for carrier transmission in high-voltage lines.

All metallic housings and flanges consist of a special aluminium alloy and can be painted in various colours. The generously sized terminal box is equipped with a cover that is to be opened sideways. This allows for easy connection of secondary cables. The terminal box is equipped with a flange without holes. On request, cable glands or individual safety devices can be built in.

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Outline Drawing of Oil Paper Insulated Capacitive Voltage Transformer ECF CVT, Instrument Transformer, mounted in a substation

Features

  • Cost-effective and reliable Design for high and very high voltages
  • Expandable for the transmission of high-frequency Signals (TFH)
  • Fabrication-internal adjustment of the accuracy classes, no on-site adjustment is required
  • Temperature- and accuracy stable over the entire service life
  • Increased safety against relaxation oscillation due to damping unit

Highlights

High and very high voltage

  • Simple and safe mounting on-site for transformers which consist of multi-piece condenser units.
  • High temperature and precision stability over the entire service life.
  • Compensation of transient overvoltages in the grid, caused by circuit breakers.

Tone frequency (PLC) couplings

  • Expandable for high frequency signal (PLC) couplings.
  • Extendable for the installation of a line trap coil.

Easy-to-fit terminal box

  • The terminal box with the lid to be opened sideways is secured by captive screws. Apart from terminals, fuses, surge arresters, additional contacts, spark gaps and sealable covers can be built in.
  • By default, the terminal box is equipped with a blind flange.
  • On request, the capacitive voltage transformer can be equipped with an additional terminal box..

Specifications and Downloads

Technical Specifications

Dimensions

Outline Drawing of Oil Paper Insulated Capacitive Voltage Transformer ECF CVT, Instrument Transformer

Technical data

Type ECF

 

72

123

145

170

245

300

362

420

550

Standard   IEC / IEEE
Highest voltage for equipment kV 72.5 123 145 170 245 300 362 420 550
Rated power-frequency withstand voltage kV 140 230 275 325 460 460 510 630 680
Rated lightning impulse withstand voltage kV 325 550 650 750 1050 1050 1175 1425 1550
Frequency Hz 50 / 60
Accuracy class   0.1-3; 3P; 6P
Rated thermal limiting output VT part VA ≤ 1000
Max. simultaneous burden (cl. 0.2) VA 150
Max. number of VT windings   5

Type ECF

 

 

72

123

145

170

245

300

362

420

550

Height of unit* A mm 1660 1930 2130 2330 2930 3310 3510 4310 5110
Height to primary terminal* B mm 1520 1790 1990 2190 2790 3170 3370 4170 4970
Depth of unit including terminal box

C

mm

746 746 746 746 746 746 746 746 746
Depth of unit base

D

mm

500 500 500 500 500 500 500 500 500
Width of unit base

E

mm

500 500 500 500 500 500 500 500 500
Distance between screw holes at base

F

mm

450 450 450 450 450 450 450 450 450
Min. creepage distance*

 

mm

2420 3540 4280 5030 7260 7820 8560 11540 14520
Approximate weight*

 

kg

280 300 320 340 400 420 450 500 540

 

*with standard composite silicone insulator, creepage distance 25 mm/kV

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