With the number of photovoltaic systems on the rise, it is vital to ensure that they are safe and comply with applicable regulations. To meet these needs, we have designed our new Sonel PVM-1530 meter which is dedicated to measuring solar PV systems operating at voltages up to 1500V and meets the requirements of IEC 62446-1.

Growing significance of solar PV system checks

The energy sector is in the process of transforming from a conventional and centralised model to a distributed model. This new approach relies heavily on renewable energy sources (RES), such as wind and photovoltaic power plants. Apart from the hundreds of thousands of microgeneration PV systems, we can also see large photovoltaic farms with substantial generation capacities being constructed.

As the number of systems being installed rapidly increases, we do not always see this matched by an increase in high quality components used in their construction. This can result in a greater risk of fire, reduced operational safety and a shorter service life. This is why it is crucial for a system, once installed and commissioned, to comply with all safety requirements and be constructed in line with applicable regulations.

In order to assess the condition of photovoltaic systems, it is essential to carry out inspections, tests and measurements. The primary document used for the assessment is IEC 62446, a multi part standard which defines the method and scope of safety checks for PV systems. Compliance with the guidelines formulated in the standard ensures that the risk of shock or fire is reduced. The tests contained in IEC 62446-1 define how to check not only the safety of a system (Category 1 test procedures), but also the efficiency of a system and its components (Category 2 test procedures).

Sonel offers a range of tools to enable the comprehensive testing of solar photovoltaic systems. The latest addition to our portfolio is the Sonel PVM-1530 meter, intended for measuring large PV systems operating at voltages up to 1500V.

Figure 1. Sonel PVM-1530 Pro kit with standard equipment

Measuring capabilities of Sonel PVM-1530 Pro

The Sonel PVM-1530 meter makes it possible to make measurements according to IEC 62446-1. Prior to making any measurements, it is important to check the photovoltaic system usually with a visual inspection of the electrical system. The visual inspection is intended to ensure that the electrical equipment has been correctly selected and installed, and that there are no visible irregularities or damaged components. The Sonel PVM-1530 has a special built-in test mode to support the visual inspection procedure to help make sure it follows the recommendations in the standard.

Once the visual inspection is complete, you can start to make the measurements. IEC 62446-1 divides testing into category 1 and 2 test procedures along with some additional tests. Category 1 testing is required as it serves to assess the safety of the system. The meter enables you to perform the following tests for category 1:

• Continuity measurement of protective connections and equipotential bonding with 200mA
• Polarity test
• Connection tests in DC junction boxes
• Measurement of the open circuit voltage of panels (Uoc) of up to 1500V
• Measurement the short-circuit current of a panel chain (Isc) up to 30A at 1500V or 40A at 1000V
• Measurement of operating current using the Sonel CMP-1015-PV clamp meter (included with PVM-1530 Pro as a standard accessory), wirelessly via Bluetooth,
• Functional tests (measurement of DC and AC power on both sides of the inverter)
• Measurement of insulation resistance of DC circuits without short-circuiting panels at test voltages of 250V, 500V, 1000V and 1500V

Figure 2. Measurement of PV chain parameters using Sonel PVM-1530 Pro

Figure 3. Measurement of operating current with Sonel CMP-1015-PV

Category 2 tests are recommended for larger and more complex solar PV systems. As a general rule, these tests can be performed once all Category 1 tests have been successfully performed and passed. The Sonel PVM-1530 meter makes it possible to measure the I-U characteristics of photovoltaic panels with a maximum power of 45kW.

Additional tests that you can perform with the meter are as follows:

• Blocking diode test with 1000V or 1500V
• Assessment of shading using the Sonel IRM-1 irradiance meter (included with PVM-1530 Pro as a standard accessory)

Figure 4. Sonel IRM-1 meter during insolation measurement

Measuring I-U characteristics

I-U characteristics are very helpful when it comes to assessing PV systems in greater detail, especially in terms of their performance and identifying potential issues. Our Sonel PVM-1530 Pro kit will be an excellent choice for determining these measurement characteristics.

IEC 62446-1 specifies that irradiance must be at least 400 W/m2 for this type of measurement. IEC 61829 clarifies that the total in-place irradiance should be at least 700 W/m2 for measurements of characteristics to be extrapolated to STC (Standard Test Conditions). PV panel manufacturers list parameters measured under laboratory conditions for the Standard Test Conditions (temperature 25°C, insolation 1000 W/m², air mass factor AM 1.5).  For comparison purposes, the Sonel PVM-1530 Pro can automatically convert measurement results to STC in accordance with IEC 60891. This is done with our Sonel IRM-1 solar and temperature meter, which works with our Sonel PVM-1530 wirelessly and with our built-in PV panel base.

Safety and ergonomics

It is important to stress that the Sonel PVM-1530 Pro and its equipment comply with the IEC 61557 and IEC 61010 safety standards and have the relevant CE declaration of conformity. With its high CAT III 1500V DC measurement category, the product can be used to measure photovoltaic panels working at voltages up to 1500V. This is crucial, considering that IEC 61010-30 qualifies photovoltaic panels as devices belonging to the CAT III measurement category.

The meter is housed in a carrying case, which means it is IP67 rated when the lid is closed. The advanced cooling system efficiently dissipates heat outside, allowing you to make measurements frequently without overheating the meter. Its large and clear to read touchscreen enables easy operation. With its high brightness, it is clearly visible even in full sunlight. The built-in Li-Ion rechargeable battery offers a long autonomous operating time, and the internal power supply unit makes it possible to charge the battery and make system measurements at the same time if the battery fully discharges during operation.

MeasureEffect™

The Sonel PVM-1530 Pro is designed to operate with Sonel’s new MeasureEffect™ standard, which involves the unification and collaboration of different metrics, with an option to add cloud solutions. MeasureEffect™ is equipped with an extensive memory, enabling the creation of a measurement structure. A wide range of communication interfaces (USB, LAN, Bluetooth and Wi-Fi) allows measurement data to be transferred to the software so that you can prepare a measurement report and connect various external accessories.

Sonel PVM-1530 Pro: a reliable solar PV system meter for professionals

With its comprehensive set of standard equipment, our Sonel PVM-1530 Pro makes it possible to make the full range of measurements for PV systems in accordance with IEC 62446-1. As a result, it is essential for engineers and contractors involved in the construction and maintenance of solar photovoltaic power plants and is a reliable tool for professionals to help maintain PV systems in good condition for many years.

Author: Marcin Szkudniewski, MSc Eng

Sonel S.A.