Kas Mohammed, VP of Digital Energy, Schneider Electric
The importance of the electrical infrastructure within healthcare is indisputable. We rely on electrical equipment to keep our loved ones safe and healthy, diagnose conditions, and find new forms of treatment. Hospitals, therefore, require an extremely reliable electrical infrastructure, immune to power failures and resilient against any issues.
Power quality disturbances are a large cause of issues in the electrical distribution system. Somewhat frustratingly, it is often the electrical equipment itself which causes electrical disturbances. In fact, 80% of power quality issues originate onsite, with the other 20% coming from the energy provider.
Onsite issues originate largely because the components within the equipment distort the electrical signal due to having loads which are non-linear current and voltage changes, such as variable speed drives and semiconductor technology, including LED lighting. These distortions can manifest in a multitude of ways such as:
- Network communication issues
- Circuit breakers tripping
- Data loss
- Flickering lights
- Unexpected equipment shutdown
- Transformers humming
This list is far from exhaustive but gives an idea of the type of disturbances to look out for. Ultimately, if the issues go untreated the results are a reduction in efficiency, increased operating costs, and damaged assets. The good news is that these issues can be easily fixed with the right solutions. However, to select the best solution, we must first understand which particular power quality issue we are trying to fix. Within a hospital, we largely see two types of issues, power factor distortion and harmonics.
Power factor issues come about when current and voltage signals do not align with one another, i.e. there is a phase difference between them. A power factor of 1 means that current and voltage are aligned and anything below this means there is a phase difference between the signals. This ultimately leads to reactive, sometimes referred to as imaginary, power being generated. This power is unusable but still charged for in the same way on your electricity bill, meaning we are paying more for our power but getting less out of it.
In fact, the cost implications of a low power factor can go far beyond this. As the power factor does not self-correct, the power we feedback into the grid will maintain any power factor effects caused by equipment on a particular site. Due to the monetary and sustainability implications of this at a grid level, the government has applied a reactive power charge to sites which are feeding low power factor signals back into the grid. These show up as an extra line on your electricity bill and mean that, combined with the costs spent on the reactive power itself, you are essentially paying twice for something which is unusable.
Power is also becoming more polluted. As a result, power quality is becoming harder to achieve and maintain. The power electronics present in digital devices generate harmonics, which occur when the electrical signal itself is distorted rather than displaced. Looking at the electrical signal, it can appear as if another, higher frequency, waveform has been superimposed on top of the signal. The cause of this can usually be traced to active electrical equipment containing variable speed drives and semiconductor technology, with X-rays and MRIs being large contributors.
In a hospital, the most common ways that harmonics will manifest are as transformer heating, humming or as disturbances on an ultrasound machine. The issue, however, is not so much the effects they cause but rather the safety and reliability consequences they bring about. Harmonics will cause electrical systems to overheat due to a larger current being drawn which not only affects asset lifetime but also greatly increases the risk of fire. Looking from a pure reliability perspective, 30-40% of unscheduled asset downtime is related to power quality issues so without rectifying the problem you will see a significantly lower efficiency for the equipment you have installed.
As a short term means of diagnosis, a power quality survey can be carried out on site by the use of a power quality analyser. These are left connected over the course of a week of normal operation to get an overview of any power quality issues over the seven-day period. This will look at harmonics, power factor, voltage spikes, sags, swells, amongst others.
However, as hospitals are very electro intensive, a more common solution is to install a range of power meters. These are installed at various stages in the electrical distribution system, from the main incomer to the hospital to various buildings and on individual distribution boards. These meters vary in the depth of power quality analysis, with more high-end meters being able to provide directional analysis to determine whether any disturbances originated up or downstream of the meter. This allows for a fast and reliable means of finding the root cause of any disturbances. Having these meters provide data into an energy management system is the best means of performing analytics and monitoring alarms and trends. These options also ensure continuous monitoring of standards compliance and can raise alarms if anything is out of the ordinary. A fully comprehensive energy management system can even help you utilise predictive analytics to preempt issues before they are a problem.
Additionally, smart distribution boards are another advantage in measuring at load level, the root cause of the disturbances. As a new or retrofit option to existing sites, using small, circuit breaker level meters can be a low cost way to ensure individual assets or systems are performing in their most efficient state.
Healthcare organisations need to investigate the types of equipment and digital applications that can help them mitigate these problems and achieve and maintain high quality power throughout their electrical network.
Luckily, the solution to most power quality issues is relatively simple. Installing power quality correction units on site will take care of the problems without manual intervention. As hospitals tend to experience a lot of harmonics on site due to active electrical equipment, the most fitting type of correction unit is active filtering. These effectively take a signal which is experiencing harmonics, low power factor, or other issues and ‘cleans it up’ to output a smoother, more reliable signal. Alternatively, if the issue on a particular site is solely power factor related, the installation of capacitor banks is a cheaper and equally effective means of fixing the issue.
Digitisation and innovation are making it easier to take a more proactive approach to power reliability. To prepare for and preempt the kinds of power-related challenges their facilities are likely to encounter—to build resilience– health systems should consider evolving diagnostic and preventive technologies and innovations such as microgrids, power automation, power events analysis and condition-based maintenance.
Using the above solutions will ensure that you are only paying for the energy that you are using and that you are getting the most out of it. Feeding better quality signals into the electrical equipment will allow them to perform at their best and prevent failures. With the need for hospitals to operate at high electrical capacity for long durations, the benefits of monitoring and acting on power quality effects are soon realised and will both save you money and protect equipment whilst prolonging its lifespan.
Uncertain situations and crises highlight the importance of using emerging technologies and innovations in healthcare systems. To build a future-ready healthcare ecosystem, it is crucial to ensure a sustainable healthcare infrastructure. Healthcare providers need to evolve with time, both in terms of facilities and services to meet the increasing demands and expectations of patients. They need to leverage the emerging technologies to ensure customers have access to disruption-free healthcare facilities. Ensuring affordable healthcare services given to customers are technology driven and sustainable is essential to ensure a resilient infrastructure.
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