3DN0 — earthing switches (separately mounted and built-in) 40.5–550 kV
3DN0 are high-voltage earthing switches for switchyards of 40.5–550 kV classes. They ground de-energized sections of the circuit before work, that is lines, busbars, transformers and other equipment. Applications cover the switchyards of 35–500 kV substations, overhead lines with parallel circuits, power plants and industrial substations.
- Rated voltage
- 40.5; 72.5; 123; 145; 170; 245; 300; 362; 420; 550 kV
- Test voltage 50 Hz
- 80–740 kV
- Lightning impulse
- 185–1675 kV
- Switching impulse (300–550 kV)
- 850–1300 kV
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Separately mounted earthing switches are offered for all voltage classes up to 550 kV, together with built-in (attached) earthing blades for all types of the company's disconnectors from 3DN1 to 3DN4. At the request of the network operator the built-in earthing switch is fitted at the side or in an integrated version. The choice depends on the position of the main current path of the disconnector.
The typical range covers rated voltages of 40.5, 72.5, 123, 145, 170, 245, 300, 362, 420 and 550 kV. The power-frequency withstand voltage to earth and between phases is from 80 kV in the 40.5 kV class to 740 kV in the 550 kV class. The lightning impulse is in the range 185 to 1675 kV, and for classes 300–550 kV a switching impulse of 850–1300 kV is also specified. The rated current is up to 1000 A, the peak withstand current up to 160/164 kA, and the short-time withstand current up to 63 kA for 1 or 3 s.
To order, earthing switches are made to switch induced inductive and capacitive currents from parallel lines. These are class A or B, including super B, under IEC 62271-102. This option is needed when a section of a double-circuit or parallel overhead line is grounded while the neighboring circuit stays energized.
The contact system is the same as in the disconnectors. Self-spring lamellas with a silver–graphite coating work without pressure springs and without lubrication, and contact pressure increases while short-circuit current flows. The design is rated for ice loads of 10 or 20 mm and temperatures from −55 to +55 °C, and maintenance is needed after 25 years.
The drive is motor-operated or manual. Control circuits are supplied from 60/110/125/220 V DC or 220–230 V AC, and motors also from 220/380/415 V three-phase. Units arrive assembled and adjusted, and no special tools are needed for installation. The devices are tested to IEC 62271-102. The company carries out installation, commissioning, maintenance and personnel training as a single supplier.
Technical specifications
| Rated voltage | 40.5; 72.5; 123; 145; 170; 245; 300; 362; 420; 550 kV |
|---|---|
| Test voltage 50 Hz | 80–740 kV |
| Lightning impulse | 185–1675 kV |
| Switching impulse (300–550 kV) | 850–1300 kV |
| Rated current | up to 1000 A |
| Peak / short-time current | up to 160/164 kA / 63 kA (1 or 3 s) |
| Switching of induced currents | class A or B (super B) under IEC 62271-102 |
| Ice load | 10/20 mm |
| Temperature | −55…+55 °C |
| Maintenance | after 25 years |
Request a price and lead time
3DN0 — earthing switches (separately mounted and built-in) 40.5–550 kV. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8535 30 10 00 8535 30 90 00 |
|---|---|
| HS, 6 digits | 8535 30 |
| CN (EU) | 8535 30 10 8535 30 90 |
| HTSUS (USA) | 8535 30 00 80 |
| China customs tariff | 8535 30 90 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Can 3DN0 ground a section of a parallel overhead line under induced voltage?
Yes, to order the earthing switches are made to switch induced currents of class A or B, including super B, under IEC 62271-102. This option is intended for double-circuit and parallel overhead lines.
What currents does the 3DN0 earthing switch withstand?
A short-time withstand current up to 63 kA for 1 or 3 s and a peak current up to 160/164 kA. The rated current is up to 1000 A.
Can an earthing blade be fitted to a 3DN disconnector?
Yes, built-in blades are made for all disconnector types from 3DN1 to 3DN4. They are placed at the side or in an integrated version.
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