Busduct instrument transformers

These ring type current transformers are available for indoor (ORF) or outdoor use (ORFE). They have been designed to meet the requirements for metering and protection duties of:
- power transformers and auto-transformers
- HV or MV wall bushings
- GIS substation
- IPB
- Homopolar detection in neutral connections

The secondary terminals are accessible either directly in the case of indoor equipment (ORF) or through a watertight terminal box in the case of outdoor application (ORFE).

As per customer’s requirement, secondary windings can integrate time constant constraints.

These ring type current transformers are available for indoor (ORX) or outdoor use (OREX). They have been designed to meet the requirements for measuring:
- line currents
- zero-sequence currents in the neutral of power transformers
- earth fault currents in power transformers.

The secondary terminals are accessible, either directly in the case of indoor equipment (ORX), or through a watertight terminal box in the case of outdoor application (OREX). Several types of terminal boxes are available depending on the required characteristics.

The change to newer, faster and more selective protective system makes it necessary to replace existing current transformers with different output, class, ratio, number of secondaries to suit the needs of the new protection.

The best solution is to use split-core current transformers on insulated cables or outside single phase metalclad units. This solution is very economical because:

- It is not necessary to dismantle and remake the cable sealing ends on the metalclad units.

- There is no need to recommission and test the main equipment.

- It reduces the risk of damage and the length of outages at reduced costs.

These current transformers are avalaible for indoor use (CRF) or outdoor use (CRFE).

These Current Transformers have been designed and developed in close collaboration with RTE, the French Electricity Network, to match the most stringent requirements of outdoor substations.

- Their « window type » design makes it possible to install them under Extra High Voltage (EHV) environment taking advantage of the insulation of primary (cable, GIS busducts, wall bushing, …)

- The CT’s with ref ATOA, ATOX, ATOY for outgoing differential protection are equipped with a filter capacitor to limit the high frequency voltage peaks showing during connect/disconnect cycles, or in case of fault on the network, and of a voltage limiter protecting CT against overvoltage in case of secondary open circuit.

The change to newer, faster and more selective protective system makes it necessary to replace existing current transformers with different output, class, ratio, number of secondaries to suit the needs of the new protection.

The best solution is to use split-core current transformers on insulated cables or outside single phase metalclad units. This solution is very economical because:

- It is not necessary to dismantle and remake the cable sealing ends on the metalclad units.

- There is no need to recommission and test the main equipment.

- It reduces the risk of damage and the length of outages at reduced costs.

These current transformers are avalaible for indoor use (CR) or outdoor use (CRE).

English version coming soon!