Solar photovoltaic (PV) panels, or modules, have become a vital resource for residential homes or commercial/industrial organisations wanting to embrace renewable energies and reduce their electricity usage. While solar PV modules are designed to operate for over 20 years, they can experience a gradual loss of power over that period, due to aging as a result of being exposed to extreme environmental stresses. And this can also result in losing power suddenly due to installation or operational issues.
Losing power in such circumstances can be a critical issue where there is a high dependency on the radiant energy being produced by the solar PV system, and so a program of constant monitoring should be introduced to check the system is generating the energy as close to the STC (standard test conditions) figures supplied by the manufacturer as possible. However, where there is a sudden loss of power you need a more immediate program of remedial action, and thermography is an increasingly beneficial way of doing that.
Using thermography for fault detection in solar panels
Thermography works the same way that thermal imaging cameras work in other forms of electrical testing and monitoring. So thermography uses a hi-resolution infrared camera, which can detect the thermal heat profile of a surface and pick up any changes in temperature through the infrared energy being emitted. This is transferred into a video image which shows the changes in temperature represented by the colour spectrum. Bright red and yellow colours denote hotspots, while blue and green colours denote colder areas where conditions are normal.
With solar panels, a thermal imaging camera can be mounted on drone technology to enable non-contact monitoring of solar panels at high levels, or a camera can be used manually to monitor panels directly. The real-time images show localised hotspots in the panels which can denote where loss of power might be experienced. Hotspots are areas of heat detected on the modules and are a sign that an electrical fault has occurred, leading to a loss of power of some degree. Hotspots can occur due to:
- Loose contacts
- Faulty wiring
- Moisture penetration
- Mechanical damage
- Component failure
These hotspots can cause an immediate loss of power, but the cause of this is not necessarily visible to the naked eye. The loss of power may also only be small, but if left can lead to high material degradation and a total loss of power across the string of solar PV panels.
The benefits of using thermography in solar PV panel monitoring
Once a solar PV panel system is installed and commissioned, it should undergo regular monitoring to ensure it is generating the energy savings the design spec suggests. It should also undergo regular inspection and maintenance, as it is an electrical installation just like anything else. The benefits of using thermography for this are:
- Fast and efficient diagnosis of electrical problems
- Non-contact and non-invasive inspection which can be carried out while the system is live and operating
- Can be used to monitor system performance over time
- Can store data from recordings to monitor and detect trends
- Detect low performance modules next to high performance modules to identify where a fault may have occurred
- Early detection of problems before a more damaging loss of power occurs
A professional program of thermal imaging inspection – using a thermal imaging camera such as the TIS 1900 supplied by Test Instrument Solutions - can result in a survey report showing how the electrical installation of solar PV modules is performing, on an ongoing basis, as well as reacting to immediate issues and providing fast and effective diagnosis of hotspots and faulty electrical installations.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.