Grounding Transformers

Grounding transformers are used to create an artificial neutral point in ungrounded three-phase power systems.

During phase-to-ground faults, grounding transformers allow fault currents and transient overvoltages to flow to the ground, thereby limiting fault currents and transient overvoltages.

Grounding transformers are expected to limit the short-circuit ground current until the circuit breaker clears the fault. Therefore, they are rated for short-time operation.

The rated power (kVA) of a grounding transformer may vary depending on the normal phase-to-neutral voltage and the value of the fault current within the specified time interval (from seconds up to minutes). We offer hermetically sealed, dry-type, and oil-immersed transformers.

Test List

• Visual and dimensional inspection
• Measurement of voltage transformation ratio
• Measurement of winding resistance
• Zero-sequence impedance measurement
• No-load loss and current measurement
• Short-circuit impedance and load loss measurement
• Insulation tests
• Separate-source AC withstand voltage test
• Induced voltage test
• Lightning impulse test
• Temperature rise test
• Final inspections

Please contact the factory for special test requests.