Short questions on software testing

Please forward this error screen to 198. Please forward this error screen to s132-148-131-123. Why short questions on software testing it important to test PV installations? Is there a standard for testing PV systems that I should be following?

Is periodic inspection and testing of PV installations necessary? What are the key warning signs that a system may not be performing as it should? What equipment is required for testing a solar PV installation? What are the key considerations that should be addressed prior to selecting a piece of test equipment? How do I test a PV installation to comply with MCS and IEC 62446?

I keep hearing about a standard for testing PV systems. Speaking to several other installers, some say that they follow it, others don’t. This is fundamentally aligned to the BS EN 62446:2009 standard for grid connected PV systems. In short, this document sets out the minimum requirements for PV system documentation, commissioning tests, and inspection to ensure the safety and quality of system installation.

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The standard describes various electrical tests to ensure that the solar installation fully complies with MCS requirements. While many of the more reputable and discerning solar PV installers recognise the importance of testing to the standard, it is of serious concern that some installers are failing to perform the required tests, or at best only partly fulfilling this obligation. Clearly where testing is not being carried out in accordance with BS EN 62446, the system will be in breach of MCS requirements and should not be eligible for feed in tariffs or be connected to the grid. This has potentially serious implications for the quality and safety of the solar PV installations in question.

For example, it was recently reported that a house fire in Kent was caused by a fault in a rooftop solar PV installation. This mirrors the situation in the USA, France and Australia where property fires and surveys of solar PV installations have raised specific concerns over incorrectly installed PV systems and their role as both a fire hazard and as a cause of increased risk of electrocution. Gemserv consultation on the competency of solar PV installers seeks to address such concerns. The MCS is due to publish new guidance in the next few weeks which will further clarify the testing requirements for PV installations. However, the solution lies in ensuring compliance with all relevant standards, including the solar PV testing and documentation requirements of BS EN62446. Only when this happens can the certification body be given the evidence that the work has been performed correctly and the customer given the assurance that absolute best practice has been followed in the installation of their PV system. Undetected faults may also develop into a fire hazard over time.

In many cases simple electrical faults or wiring failures can cause a serious inefficiency in the ability of the panel to produce power. Although metering will always give an indication of system performance, effective electrical testing is also vital not only to prove the safe installation of a new system but also to verify ongoing functional performance. The absolute minimum testing that needs to be undertaken involves continuity measurements, open circuit voltage, short circuit current, insulation and irradiance. Other tests involving the use of I-V curve tracers, power analysers and thermal imaging cameras are not mandatory but may be regarded as useful to carry out certain diagnostic testing or to assess different performance parameters of the solar PV system.

It is therefore largely up to the installer to decide whether he wishes to purchase individual items of equipment or select one or possibly two instruments which provide a combination of tests to enable measurements to be taken in a fast, safe and efficient fashion. There are many instruments available on the market that are sold under the title of Solar Testing so it is vital to ensure that the instruments selected are capable of performing all of the tests required by the IEC 62446 standard. The nature of PV testing is such that it can expose the installer to high voltages, so the selection of an instrument which is capable of automatically and safely performing tests greatly improves efficiency and safeguards the installer. The electrical output will vary significantly with changes in the level of in-plane irradiance.