Design and Applications

The TRANSFORMER PROTECTOR (TP) has several configurations of protection, which mainly depend on transformer design and customer technical specifications. SERGI Transformer Protector focuses on offering a performant, affordable and compatible solution in order to ease its implementation without interfering with the current transformer design.

The TP can be installed on existing or new transformer from 0.1 to 1,000 MVA and above. Different design is proposed according to the transformer design and location.

The main TP components are, when applicable:

Tank Depressurization Set

Fitted on the transformer to ensure fast depressurization of the main tank. According to the transformer design, one of several sets are installed

OLTC Depressurization Set

Fitted on the On-Load Tap Changer (OLTC) to depressurize each of its compartments

Bushing turrets Depressurization Set

Fitted on the bushing turrets when transformer design requires, and manholes available, to ensure fast depressurization at this sensitive point

Oil Cable Boxes Depressurization Set

Fitted on each oil cable boxes to quickly depressurize the compartment in case of short-circuit

Oil & Gas Separation Tank

Allowing to separate the oil and the gas to:

  • Prevent environment pollution
  • Channel explosive gases in a safe area

TP cabinet

Ensuring effective explosive gases evacuation after TP activation

Control Box

Informing users about the TP passive and active operations


The favored design is Vertical Depressurization Set(s) with an Oil & Gas Separation Tank located on the side of the transformer to optimize installation cost and substation design.


The TP is used in:

  • Power Industry
    • Generation: Hydro, Nuclear, Thermal, Wind, Solar, etc.
    • Transmission: for all sub-stations including HVDC
    • Distribution: distribution substations, underground transformers, etc.
  • Industries
    • Steel
    • Oil & Gas
    • Mining
    • Cement
    • Food & Beverage
  • Sensitive areas related to potential injuries or leading to critical people evacuation
    • Hospitals
    • Underground transformers
    • Building interiors
    • Schools
    • Parks
    • Airports
  • Environmental area with oil leakage risk or wildfire risk
    • Dry areas
    • Near rivers
    • Near seas
    • Near lakes
  • Communities risk which can lead to brand image reputation or politics implication
    • Highly sensitive plants, e.g. Seveso sites for the European regulation
    • Plants having relation to Nuclear industries
    • Fishing areas
    • Classified sites
    • Touristic areas