List of Essential Test & Measuring Instruments for Solar Technical Professionals

All operations and maintenance technicians look for reliability over everything else in their tools and instruments to ensure that they are able to deliver reliability themselves.

Solar technicians, like all other technicians, need all the test and measuring instruments which are required to troubleshoot, diagnose and confirm the repairs or solutions; but they specifically need suitable ones for all the various components that are part of a solar power system.

We share the list of essential tools that should be a part of every Solar technical professional’s toolkit.

1. Thermal Imager or Thermal Imaging Camera

Temperature measurement is vital for anything solar, with electricity getting combined with sunlight. Thermal Imagers prove vital to detect hotspots while inspecting electrical and breaker panels or PV modules. They can also be used to monitor cooling fluid levels like dielectric oils for transformers.

When looking for the right thermal imager to buy, consider features such as high thermal accuracy and sensitivity, high resolution and Field of View, an intuitive user interface and a good ability to visualise and diagnose issues easily.

Higher resolutions will enable the technician to isolate even the minutest temperature differences and irregularities. If the Thermal Imager has a good grip and ruggedness, the technician will be less worried about the handling and will be able to focus on the job at hand. A long-lasting battery will also help.

Micro cracks in the solar panels lead to low production and thermal imagers with a high Resolution, wide Field of View and features like low Spatial Resolution, Low NETD and AUF will enable users to pin-point hot-spots on the solar cells (which are caused by micro cracks) fast, accurately and intuitively, thus reducing the troubleshooting time and increasing efficiency for maintenance professionals.

2. Digital Multimeter

A Digital Multimeter serves as the perfect instrument for detecting voltage quickly and also comes in handy during installations and troubleshooting for combiner box and inverter.

An industrial-strength, T-RMS Multimeter with a broad operating temperature range, is a must to have.  High accuracy, range of measurements, ability to withstand drops and a dust proof & waterproof case are features to look for to help in protecting the instrument during outdoor applications.

Photovoltaic Voltage measurement, Data logging and Bluetooth, if available, will make for the perfect Digital Multimeter for all technical needs related to solar plants, installations and maintenance. Having a 1500V DC measuring range makes it useful for Solar Applications specifically.

Make sure that the test leads are premium quality and preferably made of Silicon, hence, double insulated. High Voltage test leads are also required. A holster that is magnetic as well as has test probes holder helps with one-handed operations.
Safety certifications are a must – at least a CAT III 1000V.

3. Clamp meter

A Clamp Meter serves as the most important and modern troubleshooting tool for any industrial or commercial solar technician.

A reliable and accurate Clamp Meter verifies the AC/DC load current. Ideally it should be able to measure up to 1000A in both ranges through the jaws and up to 3000A through flexible clamp for inverters, breakers, combiner boxes and disconnects. It should also be able to measure up to 1500V AC and 2000V DC for photovoltaic cells as well as the loads and line frequency in the circuits.

To ensure higher safety, a good solar clamp meter with data logging and equipped with Bluetooth, enables the user to log, trend and monitor measurements from a safe distance (from the arc flash zone).
A CAT III 1000V certification is an essential requirement and a CAT IV 600V has extra benefits. Flexi Clamp for higher current measurements, Photovoltaic Voltage, Inrush, LoZ, HFR (High Frequency Rejection), VoltSeek and AutoVolt measurements are all features which makes a Clamp Meter the perfect choice for solar professionals and technicians.

4. Solar Power Meter

Solar Power Meters assist Solar Technicians in measuring and monitoring the sunlight intensity, overall energy, efficiency and placement of all kinds of Solar Systems.

To provide the highest solar efficiency possible, panels should be mounted and angled in the most efficient location at the time of installation. Hence, Solar Panel installers and maintenance teams need to measure and compare sunlight intensity at various points of the respective installation site – be it on ground or a roof. By measuring and comparing light intensity at various locations or points, the installers ensure that the panels are placed at the best location and angle on the chosen area.

A Solar Power Meter will help determine the amount of sunlight or the amount of solar energy received by a given area in W/m2 or BTU (ft2*h). This helps immensely in determining optimum placement of solar panels.

The instrument should be made for rugged use as it is to be used in direct sunlight for long periods. High Accuracy and Rapid Response as well as Data Hold functions to hold measurement values are what to look for in an ideal solar power meter.

5. Insulation tester

Digital Insulation Testers able to measure insulation resistance up to 10kV are suitable for Solar technicians and professionals; as they have to test high voltage equipment like cables, switchgear, motors and conductors. Insulation Testers help with a variety of tests including identifying power quality failures, breakdown tests, spot checks as well as timed tests.

A reporting tool, if available, is a bonus and real time trending and remote test configurations as well. Bluetooth, if available, allows for online data transfers and then eliminates the need for recording notes or data. All these features go on to making the tester an indispensable tool for solar technicians.

6. Battery Analyser or Tester

Solar professionals and technicians also need to check batteries on solar storage systems, Battery Analysers or Impedance Testers help implement performance testing as well as perform troubleshooting on battery banks and stationary batteries. Most Battery Analysers are capable of working on various kinds of batteries.

A good Battery Impedance Tester should be capable of accurately measuring internal Resistance, Voltage, Current and Temperature of the battery. A PC interface & software feature will help further to analyse the data collected and get comprehensive trend reports.

Compact design meant for rugged use and an intuitive user interface are must-haves.

7. Clamp-on Power Meter

Solar Power Clamp-On Meters are especially designed for solar installers and technicians who carry out diagnostic tests.

During installation on a PV System, a clamp-on power meter can be used to ensure that the inverter is operating correctly or even for maintenance and troubleshooting post commissioning. If a PV System does not generate expected levels of power under given irradiance & temperature conditions, one or more components in the system might be faulty.

Solar PV systems last over 25 years and for efficient operations, periodic and regular inspection and testing is essential. Most inverters last much less than the whole system, so they require attention, especially during maintenance and testing.

Inverters are generally designed to generate power at unity power factor, particularly at full power. The actual requirements vary, but for example, the power factor must be greater than 0.90 for generated power greater than or equal to 50% of full power. The best way to measure for the same is by using a clamp-on power factor meter.

A meter with datalogging is ideally able to record data with respect to time, which enables understanding the power factor with respect to power generation loads.

8. Non-contact Infrared Thermometer

Infrared thermometer offers rapid and accurate temperature measurements and prove to be ideal tools for measuring surface temperature on Solar cells, panels and arrays, especially in hard to reach areas. The built-in laser guides make it a simple job to fix on the target object and gauge the surface temperatures.

The accuracy of any infrared temperature measuring device is influenced by the emissivity (ability to emit infrared energy) of the surface being measured. Infrared thermometers used should be be calibrated for the PV modules emissivity.

Hence, Infrared Thermometers used should have adjustable emissivity, adequate distance to sight ratio to enable measurement from distances, multiple or circular lasers which make it easy to mark the area for which surface temperature is being measured and of course, appropriate temperature range.

Safety is Foremost

The above instruments or tools are basically required by any solar professional or technician to diagnose, troubleshoot and confirm repairs for any solar PV installations or components. They are to be definitely used safely, while ensuring ideal usage of Personal Protective Equipment. CAT and other safety ratings are always to be looked for in all the above instruments, which are meant for the specific solar working environments. The instruments should be from a reputed brand which ensures reliability, accuracy and quality.