Eaton Xiria, Xiria E, NGX and Power Xpert UX Switchgear

Short answer

Xiria is Eaton's family of switchgear for ring main units and secondary distribution, SF6-free: it insulates with air and interrupts in vacuum, up to 24 kV and 630 A. Xiria E is the extensible version and Xiria NGX the higher-performance one, up to 1,250 A and 25 kA. Power Xpert UX and XGIS are Eaton's switchgear for primary distribution.

What it is and where it is used

Eaton Xiria switchgear (including Xiria 630, Xiria E and Xiria NGX) are ring main units and secondary distribution switchgear without SF6: they insulate with air in a sealed tank and interrupt in vacuum. They are used to operate underground distribution rings and protect transformers, in distribution networks, buildings, industry and infrastructure. For primary distribution Eaton offers Power Xpert UX (air-insulated) and Power Xpert XGIS (gas-insulated).

The Lucy Sabre is an RMU from another manufacturer, with the same function in distribution networks. For the principles of this equipment, see medium-voltage switch-disconnector and medium-voltage switchgear.

Variants: Xiria 630, Xiria E, Xiria NGX, Power Xpert UX, XGIS and Lucy Sabre

Model	Application	Main difference
Xiria (block)	Secondary distribution RMU	Up to 24 kV, 630 A, AFLR internal arc 20 kA/1 s
Xiria E	Substations that expand	Extensible version
Xiria NGX	Demanding secondary distribution	Up to 24 kV, 1,250 A, 25 kA/3 s
Power Xpert UX	Primary distribution	Eaton air-insulated switchgear
Power Xpert XGIS	Primary distribution	Eaton gas-insulated switchgear
Lucy Sabre (VRN2a…)	Distribution RMU	Different manufacturer: Lucy Electric

The published values are for the range; those of an installed unit are on its nameplate.

Main characteristics

SF6-free: dry air without overpressure in a sealed tank and vacuum interruption, based on Eaton’s vacuum interrupters.
Ring and transformer functions: switch-disconnectors for the ring and a vacuum circuit breaker with relay for the transformer.
Earthing switch and interlocks on each function.
Voltage presence indicators and plug-in cable connections.
Motorization to automate the distribution network.

Without SF6, managing the equipment is simpler: there is no gas to recover at the end of its life and no fluorinated gas controls. Inspections focus on the insulation, the condition of the vacuum interrupters and the mechanism. Cable connections, terminations and voltage presence indicators remain points to check at each maintenance and with thermography, because that is where heating appears.

Communications and integration

Motorized Xiria units are integrated into the utility SCADA with a remote control unit that reports positions, fault passage and alarms over IEC 60870-5-104, DNP3 or Modbus. The circuit breaker function is integrated through its relay. See substation RTU and gateway and IEC 60870-5-104.

How a Xiria E is built

Eaton’s Xiria E brochure is in English and is an earlier edition. The range has changed since then, so it is useful for understanding the design and not as a data sheet for an installed unit. It describes the Xiria E as single-busbar switchgear, solid- and air-insulated, for up to 24 kV, and details the components that matter for testing and operation:

Vacuum circuit breaker: Eaton vacuum interrupters that the brochure declares maintenance-free and certified for 30,000 operating cycles, driven by a spring mechanism with few moving parts and no lubricants, in an enclosure sealed for life. It can be manual or motorized, with position indication through inspection windows and mechanical indicators and open and closed auxiliary contacts.
Two-position selector (“service” and “earth”): it is in the same sealed enclosure and connects the breaker to the busbars or to the earth points. Its three shafts are mechanically interlocked, so it can only be operated with the breaker open. On the vacuum circuit breaker panel, according to the brochure, earthing is integrated in this selector and is operated with the breaker open.
Busbars: insulated per phase and by air, inside the same sealed enclosure, with electric field control to reduce the risk of internal arc.
Voltage detection: each panel has a three-phase capacitive voltage detection system compliant with IEC 61243-5, which tells the operator whether the panel is isolated from the source.
Interlocks: mechanical and electrical; among them the one that prevents operating the selector with the breaker closed, and the one that prevents opening the cable compartment door while the breaker is not in the earth position. To return to service the door must be fitted again.
Voltage transformers protected against ferroresonance: the brochure shows a resistor and a saturable coil in the tertiary circuit of the voltage transformer, because ferroresonance can damage the transformer and cause an internal arc.
Internal arc: design tested to IEC 62271-200, with a metal enclosure that contains the arc and, where it cannot be vented into a basement, a rear flue with arc absorbers that discharge it toward the room.
Dimensions and maintenance: panels 500 mm wide, cable connection from the front, 12 kV and 24 kV panels in the same enclosure. Eaton highlights that, without SF6, there is no gas pressure to check and no gas to manage at end of life.

The family is organized, according to the same brochure, into three lines. The Xiria blocks are three-panel units, later extended to two, four and five. The Xiria M metering version serves for billing. The Xiria E is modular and extensible, and is intended for installations with more panels or more demanding specifications: utility distribution substations, wind farms, large industry, hospitals, data centers, tunnels and airports, among others.

Withstand voltages and range values

The family data sheets we consulted (different versions and dates) agree on a maximum of 24 kV and 630 A for the block Xiria, with internal arc classified AFLR 20 kA for 1 s. A range table lists rated voltages of 3.6, 7.2, 12, 17.5 and 24 kV. The power-frequency withstand voltage is 28, 38 or 42 kV for the 12 kV class and 50 kV for 24 kV. The impulse withstand is 75 or 95 kV and 125 kV respectively. Another edition of the catalog gives 21 kA instead of 20 kA for the internal arc; the difference is another reason to read the nameplate and the type test report of the unit on site, not the generic range sheet.

What is verified on receipt and at commissioning of a switchgear unit

Commissioning an SF6-free switchgear unit is not limited to “measuring insulation”. In general the following are reviewed:

the condition of the mechanical and electrical interlocks, which are the operator’s protection;
operation of the selector and the breaker, their timing and operation count;
vacuum integrity and enclosure insulation, according to the method the manufacturer accepts;
the voltage detection system and the phase sequence at the terminals;
the integrated current and voltage transformers and the secondary wiring to the relay;
cable testing when the design provides for it, with the compartment open and in the condition the manufacturer defines.

The procedure and acceptance values are defined by the manufacturer’s manual for that model; here the points are only listed to plan the visit. More context in vacuum integrity test and medium-voltage switchgear. For Eaton’s medium-voltage vacuum breakers, see Eaton W-VACi, VCP-W, VCP-WG and Magnum breakers.

Frequently asked technical questions

Xiria documentation: Eaton publishes the catalog and the instructions for the range; the unit’s dossier indicates the functions delivered.
Tests on an SF6-free switchgear unit: insulation, contact resistance, mechanisms, interlocks and vacuum integrity are tested; there is no gas to analyze. See vacuum integrity test.
Lucy Sabre: being from another manufacturer, its manuals and spare parts are requested from Lucy Electric.

How we help

We do not sell switchgear. At Tiza Group we test ring main units and medium-voltage switchgear (insulation, contact resistance, vacuum, mechanisms, interlocks and cables), review the transformer protection and support commissioning, in substations and in industry, in Colombia or elsewhere on request. See circuit breaker tests within testing and commissioning. Write to us through the contact page.

References

IEC 62271-200, metal-enclosed switchgear and controlgear for 1 kV to 52 kV.
IEC 62271-103, switches.
Eaton, Xiria catalog page (medium voltage power distribution) and Xiria NGX documentation.

Frequently asked questions

Does Eaton Xiria switchgear use SF6?

No. Eaton presents Xiria as an SF6-free family: the insulation is dry air inside a tank sealed for life and interruption takes place in vacuum interrupters. That means there is no greenhouse gas to monitor or recover at the end of its service life.

What are the ratings of the Eaton Xiria 630?

Eaton publishes the Xiria up to 24 kV and 630 A, with an AFLR internal arc classification of 20 kA for 1 s. The Xiria NGX reaches 1,250 A and 25 kA for 3 s. The data of an installed unit are on its nameplate and may be lower depending on the configuration.

Is the Lucy Sabre an Eaton product?

No. Sabre, with references such as VRN2a, is a ring main unit from Lucy Electric, a different British manufacturer. It serves the same function as Xiria in distribution networks.