Why OneFit Retrofill is more than a replacement breaker for your old switchgear

The latest hard-bus retrofill design from ABB can fit both your short-term and long-term asset management strategy.

Standardize your plant and modernize obsolete panels - from most manufacturers - using ABB MV breakers, that can be included in the maintenance budget (Opex - Operating Expenditure). Reuse the same breakers without any modification during the next substation renewal when you are ready for full switchgear replacement (Capex - CAPital EXpenditure). Here is a guide to the flexible OneFit retrofill packages and additional options to optimize your investment.

What everybody ought to know about Retrofit

Circuit breaker retrofit is a cost-effective switchgear modernization solution with various approaches, described in detail in 
"4 types of retrofit breakers: which one to choose?". The result is a noticeable improvement on reliability, safety, maintenance and performances.

See Figure 1.

Circuit Breaker Retrofill definition

CB retrofill is a modernization process including the replacement of the circuit breaker and some of the functional components of the power compartments. It is applicable where the existing switchgear frame is in serviceable condition. This includes a range of solutions supporting the switchgear upgrade when additional constraints are in place:
  • other parts than the breaker (shutters, interlocks, etc.) need to be replaced;
  • the original panel design does not allow to meet the features and standards required today.

 See Figure 2.

What is special about ABB's OneFit Retrofill concept

OneFit is the latest ABB hard-bus retrofill design concept, embedding an integrally safe plug-in technology that allows to easily connect the new breaker to a wide range of existing panels. OneFit is composed by a frame hosting the new circuit breaker. It is connected to the existing switchgear bushings by an additional power circuit, that acts also as inner interface with the new CB. 

See Figure 3.

This solution balances the need for a retrofill solution with reasonably limited site works and linked outage

1. Existing panel
2. Copper Adaptation System
3. Insulating shell
4. Insulating plate
5. Basement
6. Shutter
7. Frame
8. ABB new standard breaker
9. Door (on request)

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Which switchgear upgrade option is the best for you?



Safety Plus

ESafety Plus

The true retrofill solution Personnel protection increase A new operational safety level Integral equipment revamping

Personnel protection increase
New metallic partition shutter X X X X
Increased dielectric properties thanks to new insulating arrangement X X X X
Loss of service continuity category: upgrade of LSC-1 & LSC-2A switchgear to LSC-2B PM (busbar, CB & cable compartments physically & electrically segregated with metallic partitions and shutters) X X X X
New apparatus racking with standard interlocks X X X X
Apparatus racking in and out with closed door X X X
Motorized apparatus racking in and out for all vacuum breakers / contactors X X

Integral equipment revamping
Remote control and advanced protection relay X
Integrated current sensors with no heat dissipation X
Combined voltage sensors unaffected by ferroresonance risk X

Earthing switch functionality
New interlocking functionalities X X X X
Cable testing truck * * * *
Earthing truck, also with making capability * * * *

New internal arc safety level
Relay retrofitting with Relion® family embedding arc detection inputs * * * *
Switchgear upgrade - REA arc flash mitigation relay * * * *
Integration of active arc protection system UFES (Ultra Fast Earthing Switch) * * * *
X In the package * Additional options

See how easy and fast it is to implement OneFit

Data Collection Feasibility Study Design Phase Final Solution
The existing equipment data collection is performed at site by either the use of conventional instruments or much faster with the support of a 3D scanning system.
No need anymore for the original apparatus during the design phase.
TheGlobal Parametric Toolenables ABB users to easily convert the gathered original equipment data into a professional and quick feasibility study. The Global Parametric Tool allows to standardize and optimize the engineering phase. A process which could take weeks of work can now bedone in a few hours. A refined output of the Global Parametric Tool enables afast production implementation and a quick deliveryof the complete solution.

Operational benefits in short and long term

OneFit retrofill approach will let your operations win both in short and long term:

  • the new apparatus embeds standard spare parts with all the benefits in terms of availability and delivery terms
  • equipment and spare parts are interchangeable with new ABB extension panels and additional switchgear
  • plant standardization: revamping of different original manufactured panels using same standard ABB apparatus
  • same operational interface and maintenance approach for the equipment installed in OneFit and new ABB panels
  • site activity closed by an operational training for your personnel
  • possibility to operate and serve MV equipment with reduced and predictable maintenance costs thanks to a modular service level agreement

See Figure 4.

Full apparatus range

VD4: vacuum breaker with mechanical actuator
VM1: vacuum breaker with magnetic actuator
HD4: SF6 gas breaker with mechanical actuator
VSC: fused vacuum contactor

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