A digital transformation is taking place within buildings worldwide. A few of the earliest dimensions of this have been in industrial and building automation systems. These have been closely followed by digitization of both low voltage (LV) and medium voltage (MV) level electrical distribution systems. Increasingly permeating these systems are digital power and energy meters, smart circuit breakers, communication networks, and powerful analytic applications. In this blog post, we’ll have a look at a new trend in MV monitoring that is helping to improve safety and extend the lifespan of equipment.
The risks faced by MV equipment
According to the National Electrical Testing Association, the top five causes of failures in electrical equipment are:
- Loose connections (25% of cases reported by insurance carrier)
- Electrical insulation breakdown
- Water penetration from various origins
- Breaker racking
- Faulty ground fault protection
Installation and/or maintenance errors may cause some of these issues. However, many can also result from other stresses that cause premature aging of components. Though medium voltage electrical equipment will come with a rating of expected lifespan under normal conditions, it often has to operate in very challenging environments that can degrade components over time. There also can be mechanical stresses, such as vibration, in addition of environmental stresses caused by heat and humidity. Airborne pollutants that adhere to parts of MV equipment can further exacerbate these problems.
As promoted by the ‘circular economy’, especially during the in-use life phase, simply put, it is better to avoid the cost and wastage of replacing products by doing everything possible to extend their lifespan. This may require maintenance or upgrades to extend the durability and to maintain the high level of reliability. For example, technologies available today are optimizing MV equipment dependability though predictive maintenance limiting preventive maintenance and reducing corrective maintenance.
The digital transformation of MV systems is helping ‘light up dark assets.’ In other words, it gives operations teams a new level of visibility inside their MV assets on a continuous basis. By staying better informed about equipment conditions, personnel can be more proactive in identifying problems earlier, which helps to reduce downtime. Further, having advanced level insight into equipment conditions can support a more holistic view. This can allow for a predictive maintenance approach to help avoid failures, as well as reducing maintenance requirements and costs.
Seeing deeper inside MV assets
The risks to MV equipment can be greatly mitigated with tools that can assess those threats, some of which may otherwise go undiagnosed. Innovations in sensor technology and the Internet-of-Things (IoT) are enabling more and more critical points throughout an MV system to be comprehensively monitored and analyzed.
For aging electrical equipment, the main influencing causes are temperature, humidity, pollutants, and load factor. Each of these factors can be monitored with appropriate sensors and metering. For example, innovations in thermal sensing technology are enabling sensors to be installed on connection points on busbars or conductors inside switchgear, control panels, or transformers. These thermal sensors will continuously monitor for any abnormal temperature rise, which may indicate a loose connection that could eventually lead to electrical arcing, failure, and fire. This is a more comprehensive and cost-effective approach than IR thermography done only on a scheduled basis, and only on selected connection points.
These and other types of sensors and smart devices are connected over a choice of communication network technologies to efficiently transfer data to locally-hosted or cloud-based analytic applications. For some types of sensor installations, wireless communication technologies provide a convenient, non-disruptive, and cost-saving alternative.
Depending on the application, the appropriate communication standard(s) should be followed:
- For substations, the IEC 61850 series of standards should be followed to maximize uptime.
- The IEC 62351 standard should be used for secure communication protocols.
- For general information systems, including cloud solutions, the IEC 27002 and IEC 27019 standards should be applied.
- For substation devices (HMI, relays, RTUs) and their associated control systems, the IEC 62443 is more relevant.
- For all devices, a wireless solution that offers a secured protocol should be chosen for easier installation.
Analytic apps will track all equipment and environmental conditions, alerting on anything that exceeds safe thresholds in terms of value or gradient. With alarm and data access via mobile devices, facility teams can respond to risks before they cause damage or downtime. Some apps now also offer advanced algorithms that estimate equipment aging based on current and past operational and environmental conditions. This provides a more accurate assessment of equipment health and maintenance requirements to help optimize performance and extend the life cycle.
Schneider Electric offers industry-leading MV and LV electrical distribution, protection, and control solutions. As well as complete, digitally-connected power and energy management solutions that are enabling digital transformation and workflow collaboration across buildings, data centers, infrastructure, and industry worldwide. For more information, download the Medium Voltage Technical Guide.