Epoxy Resin Cast Dry-Type Earthing/grounding Transformer 30kV 34.5kV 35kV

Scope of Application

• This product is suitable for three-phase, 50 Hz power grids of 6 kV, 10 kV, and 35 kV.
• It is mainly used to provide an artificial, loadable neutral point for unearthed neutral systems for system grounding.
• It features Class F insulation, designed for indoor use, and can be used outdoors when equipped with an enclosure.

Detailed Information

• Overhead lines are susceptible to electrostatic charges induced by nearby charged clouds, dust, hail, fog, and rain, which alter the line-to-earth voltage. As these induced charges accumulate, the line and connected equipment develop a high floating potential to earth, endangering their insulation. Artificially grounding the neutral point conducts these induced charges to earth, preventing potential damage to lines and equipment.
• High-voltage oscillations are common in systems with an insulated neutral. Grounding the neutral point minimizes these oscillations.
• In systems with an insulated neutral, a single-phase earth fault typically manifests as an arcing earth fault, producing intermittent arcs. The voltage of the healthy phase lines to earth rises to the line voltage, and the line-to-earth capacitive current increases to 1.732 times its normal value. The capacitive current at the fault point is 1.732 times that of a healthy phase-to-earth capacitive current, resulting in a total fault point capacitive current three times the normal line-to-earth capacitive current. By connecting an arc suppression coil between the system neutral and earth, the inductive current flowing through the coil compensates for the capacitive current at the fault point, quickly extinguishing the intermittent arc automatically.
• Deriving an artificial neutral point from an insulated neutral system and grounding it (without an arc suppression coil), in conjunction with automatic protective devices, allows isolation of the faulty section at the initial stage of the fault.

• It must have a neutral point that can be grounded to facilitate system neutral grounding.
• In the event of a single-phase earth short circuit, the earth current at the fault point must flow smoothly through the grounding transformer windings back to the line, providing sufficient fault current information to the automatic protective devices.