When issues arise in LV switchgear, engineers and electrical distribution stakeholders must act quickly to safely restore system functions by either retrofitting or replacing the unit.
Continuity of service and operator safety are fundamental in the operation of LV Switchgear. The typical lifespan of LV switchgear is 20-25 years, whilst the lifespan of individual components can vary considerably. As a result, system reliability can become reduced in ageing switchgear systems as components and connections wear out and become loose, which in turn compromises the safety and efficiency of switchgear operations.
An LV switchgear retrofit consists of completely removing worn or defective components from the enclosure and replacing them with either brand new or recycled functional components. The aim of retrofitting is to extend the useful life of the existing equipment by restoring system efficiency, safety and reliability to the current system. Retrofitting has a low environmental impact compared to a switchgear replacement as less materials are discarded. A phased retrofit approach can be taken when modifying a large section of the overall system to minimise the network disruption.
As the name suggests, this method involves completely replacing the existing switchgear with brand-new equipment. All cables are disconnected from the current system which is then moved off-site before the new switchgear is integrated into the overall power system. The replacement process typically involves much longer lead times and a more complex installation process than a switchgear retrofit. However, it also offers a longer life expectancy and the opportunity to benefit from newer and more efficient technologies that are compliant with modern switchgear standards.
The Deciding Factors
As the structural work typically has a longer lifespan than the functional components, retrofitting solutions are a common quick fix to restore switchgear efficiency and reliability. However, determining the most suitable solution for your equipment is a complex process, impacted by a multitude of variables. Therefore, it is vital to carefully consider the following key points when assessing whether a retrofit or replacement is the most suitable option for your LV switchgear
1. Severity of the problem
The first step to choosing the most suitable solution is assessing the severity of the problem. Have the inefficiencies resulted from one defective component or is there larger underlying issue with the overall switchgear unit? For instance, if the system is nearing the end of its life span, it is possible that connections have come loose, or insulation has worn resulting in reduced reliability. Another issue with aging switchgear is capacity. Over the years fault levels have increased to exceed the original short circuit withstand rating of equipment, creating a safety hazard for operating personnel. In these instances, a replacement system would be much more efficient than a retrofit as the extent of the issues go beyond a defective component that can be easily extracted from the enclosure and replaced.
2. Availability of spare parts
New technologies are being developed at a rate that far surpasses the typical lifespan of any LV Switchgear system. As a result, availability of spare parts may be limited for older systems. This presents switchgear engineers and stakeholders with two key issues. (1) The limited availability of parts is likely to result in increased future maintenance and retrofit costs (2) Continuity of service will be at risk if replacement components cannot be sourced. Therefore, in such cases it might be more economic to replace the switchgear, to avoid potential loss of critical service.
However, for modern systems where replacement components are widely available, retrofitting the defective component with a new device is the more cost-efficient method for restoring system reliability.
When comparing the cost of retrofit and replacement LV switchgear, both the capital cost and future maintenance costs must be considered for each method. Retrofit solutions typically have a lower capital cost as only one component within the system is being replaced, however, future maintenance costs can creep up as other components and connections within the original unit wear out.
Naturally, replacing an entire switchgear system will incur a significantly higher capital cost than a retrofit solution as all elements of the previous system are discarded and replaced. Modern switchgear tends to have a smaller footprint than older systems, therefore existing electrical conduit will need to be replaced or repositioned and cabling may have to be replaced to fit new connection points. The additional work required to facilitate a switchgear replacement can add significant cost onto the cost of the equipment. This is why so many companies choose to retrofit switchgear, avoiding switchgear replacement until it is the only feasible solution remaining.
How mission critical is the power supply? Can scheduled downtime be afforded? If the answer to the above question is ‘no’ then a system retrofit may be the most feasible solution, as swapping out a single component within the system requires minimal disruption to LV switchgear operations.
Alternatively, a switchgear replacement will typically take much longer to complete than a retrofit as the existing switchgear must first be disconnected and removed before installation of the new system can begin. Additional complications such as incompatible connections can also result in longer periods of downtime.
It is important to understand that when deciding whether to retrofit or replace, there is no ‘right’ or ‘wrong’ answer as each solution has its own benefits and drawbacks depending on the situations they are applied to. For instance, whilst a switchgear replacement will have a higher capital cost and incur longer periods of downtime, this method enables companies to upgrade to newer systems with more efficient designs, in turn providing longer term cost savings. Therefore, it is essential to undertake a careful analysis of system operations and the external environment to evaluate which of the two options is the smartest solution for you.