Inductive voltage transformers are designed for 72.5kV to 800kV systems and are used to provide voltage for metering and protection applications

Features of Trench voltage transformers include:

• Modern, lightweight design with high dielectric and mechanical strength.
• Hermetically sealed construction.
• High thermal burden capability (2500 VA or higher).
• Power voltage transformers up to 30kVA.
• Available in high accuracy designs.
• Transmission line discharge capability.
• Zero delay transient response
• Ferroresonance suppression designs.

Current transformers are available for applications from 72.5kV to 800kV systems, for relaying cores, metering cores are offered in various combinations.

All Trench current transformer designs are based in "top core" or "heat type" construction. Features of this design and construction include:

• Extremely high mechanical strength under short-circuit conditions.
• Immunity to localized core saturation.
• Negligible voltage drop across primary winding.
• Hermetically sealed construction.
• High seismic withstand.
• Low partial discharge levels at test voltage.
• Optional ground fault CT's and capacitance taps.
• High accuracy designs (0.10%).
• Broad range metering from maximum to less than 1% of rated current.

The Trench combined instrument transformer (CIT) offers the station designer the possibility of being able to accommodate the current transformer and the potential transformer in one, free-standing unit. This allows optimum use of substation space while yielding cost savings by elimination of one set of mounting pads and support structures. In addition, installation time is greatly reduced.

As with individual current transformers and potential transformers, Trench CITs are available with either oil/paper or SF6 gas dielectric systems.

All operating and construction features are similar to those listed for the individual current transformers and potential transformers.

Trench offers an unparalleled scope of supply with the ability to provide CITs up to 800kV.

Capacitor voltage transformer (CVT's) are available for voltage ratings of 69kV - 800kV and are used to provide voltage for metering and protection applications. All CVT's are available with metering or relaying accuracy. Features include:

• Highly reliable insulation system.
• Film/synthetic fluid dielectric.
• High stability of capacitance and accuracy.
• Hermetically sealed construction.
• Stainless steel expansion chamber with controlled pressure release.
• Extra high strength porcelain for line trap mounting.
• Composite insulator designs available.
• Oil insulated base box for maximum reliability.