Retrofitting Switchgear

Retrofitting is particularly attractive to organizations with a large volume of ageing installed equipment and where asset rearrangement budget is limited. A major attraction of retrofitting is elimination that need for disruptive re-cabling and not needed for civilian, transformer or cabling works.

Retrofitting switchgear can extend the life expectancy of current assets by 30 years, dependent on the switchgear panel’s condition, whilst offering minimal disruption. For a straightforward retrofit circuit breaker option, site times are very short, perhaps even less than one day per circuit.

A typical retrofit solution involves rearranging old circuit breakers with modern exhaustion circuit breakers.

Benefits of Retrofitting Switchgear are:

• Maintains the fully certified rating of the joined replacement circuit breaker /existing switchgear
• Considerable life extension to your original switchgear
• Provision of a very low maintenance circuit breaker with few consumable spares
• Long term minimal cost of ownership
• Proven reliability of replacement circuit breaker
• Provision of a cost-effective method for the removal of bulk oil products
• No expensive civil works or HV cable disruptions needed
• Remove the need for great capacity/high maintenance auxiliary power supplies
• Provision of circuit breakers with electrical trip/close facility
• Improvement of Health & Safety by removal of Oil or SF6 gas
• Lower owner costs
• Practically no maintenance requirements
• Uses existing design of primary and automatic secondary contacts

All CoreSystems retrofit solutions fit with our outstanding, patented magnetic activator.

Our patented, single coil magnetic activator and electromagnetic spring innovations have been widely acclaimed, ground-breaking developments, which have provided Hawker Siddeley Switchgear with a world leading edge in circuit breaker technology.

Independently recognized by the Royal Academy of Engineering and the prestigious Queen’s Award for engineering excellence, the activator coil energized in one direction to ‘power close’ the circuit breaker and within the wrong direction to open it by de-latching the holding force.  This unique feature of the activator design used in our ‘Fit & Forget’ range of products and make sure reliable tripping operation under all battery conditions and even for manual trip.

Switchgear Maintenance

Electrical equipment manufacturers generally need annual maintenance for power circuit breakers to make sure proper operation and to manage equipment warranties. This maintenance consists of cleaning and lubrication of both primary and secondary disconnects, racking mechanisms and cell interlinks.

A Thorough Site Maintenance Work Scope for Circuit Breakers Includes:

• Inspection
• Cleaning and lubrication
• Adjustments
• High electricity protective device testing
• Insulation testing
• Charge/close/trip circuit testing
• New or refurbished parts or subassemblies may need to return the circuit breaker to good operating condition.

Deep maintenance opportunity for circuit breakers in-shop reconditioning. With this opportunity, the breaker tested at the beginning against ANSI standards and then completely disassembled, cleaned and inspected.

Damaged parts refurbished or replaced and pivot points re-lubricated before the circuit breaker reassembled. The reconditioned breaker retested to ANSI standards, including primary injection or timing.

Even with annual maintenance, however, power circuit breakers may need further upkeep or upgrades. Factors to consider include the operating environment, availability of spare parts, reliability and the cost of ongoing maintenance. There may need to increase the switchgear’s fault, continuous current rating or the motive to upgrade technology. Facility managers usually face the choice of managing ageing or ancient equipment or replacing it with  new switchgear line-up to take advantage of current technology.

Considering Switchgear Replace Versus Switchgear Repair

When considering whether to manage equipment or to replace it, facility managers must take into account the basic capital cost, along with potential disruption to the facility’s processes and workflow during course of swapping out the equipment. But process loads can rerout temporarily during demolition of old equipment and installation of the new switchgear, the cost of lost production can extraordinary.

Conduit placement is another option which is often overlooked. Installing new switchgear, which is usually smaller than the older equipment, requires that existing conduit above and below the equipment be moved. Cabling may have to replace or splice as well. This is an expensive and time-consuming process, and often costs more in terms of labor and material than the new equipment itself.

Facility managers now have another option to consider in the repair versus replace debate. New design capabilities exist to modernize and extend circuit breaker life while leaving the existing switchgear structure perfect.

Modernize and Upgrade Switchgear

Modern power circuit breakers use space-age materials in very compact formats, with digital trip units. They also offer very high fault current withstand ability without using limiter fuses. These design improvements are a quantum leap forward in equipment and organizational protection. They also have lower maintenance requirements than the older, open iron-frame circuit breaker designs.

Several retrofit strategies exist for accommodating modern circuit breakers into existing low-voltage and medium-voltage switchgear structures.

Direct Replacement of Switchgear

Direct replacement circuit breakers and circuit breaker retrofill solutions are different processes but both have the same conclusion: improved power system reliability and lower life-cycle costs.

Retrofit Switchgear

The real switchgear cell and bus modified to get new circuit breaker. This process usually requires a longer bus outage during which time the internal circuit breaker cell modified to accept the new circuit breaker. Retrofill solution usually used substitute for direct replacement choice for larger devices such as main breakers and tie breakers. In these cases there may not adequate room in the existing circuit breaker cell to allow for the intermediate cradle used in the direct replacement option. This is due to the size of the replacement device.

Importantly, new cubicle doors provided in both retrofill and direct replacement options to match the existing equipment and new circuit breaker face.

Choosing the Right Switchgear

The state of the equipment and the cost of doing the work should decide factors here. Another consideration is the need to integrate new technologies to improve performance of the circuit breaker and that of the overall electrical system.

Why Upgrade?

Improved reliability

• Dash-pot style or air breaker interrupting devices on existing circuit breakers may have reliability issues. Many do not trip at all while those which do trip are not repeatable and may well outside the time-current regulation parameters.
• Ageing materials reduce equipment reliability. Dielectric breakdown of insulating components and degradation of ageing mechanical parts occur.

Reduced maintenance costs

• Older power circuit breakers require extensive periodic maintenance and overhaul, which is expensive and time-consuming. This lengthens outages and may require outside support.
• Many components for existing circuit breakers are no longer supported and new parts may no longer be available. The capacity and quality of used or reconditioned parts is decreasing. Prices of the parts are on the increase.

Increased abilities

Fault current interruption – new circuit breakers are available with higher ratings. In most cases, the interruption capacity of the entire switchgear can increase with an engineering study and a circuit breaker upgrade or replacement.

The Benefits of Retrofit

• Patented single coil design;
• Minimal moving parts;
• Bi-stable with pulsed coil to produce;
• High strength rare earth magnets;
• Opening energy stored during closing;
• Tripping performance independent of supply voltage;
• Over 30,000 in service.