Lynn D. Churchill, Ph.D.

 An extensive review of the literature regarding solar inverters used in solar energy systems and interviews with solar dealers has disclosed issues and concerns regarding their life expectancy and potentially dangerous EMF production. Solar inverters are the essential components that convert DC power produced by the solar panels into AC power that can be used by a residence or business. The purpose of this brief paper is to illustrate how the Satic Solar Power Perfect Box can be used to address some of the most common issues and concerns with solar inverters.

 Interviews with solar companies and installers indicate that the typical solar inverter has a life of expectancy of 5-10 years. Some have shown an even shorter lifetime due to component failure. Inverters primarily fail due to transients (harmonics) from the grid or photovoltaic (PV) generator, component aging, and operation beyond the designed limits. Inverter components such as capacitors can age quickly or fail for any of the following reasons:

• Electrolytic materials age faster than polycarbonate and other dry dielectric materials
• Voltage stress
• Continuous operation under max voltage conditions
• Frequent short-term voltage transients
• Current stress
• High current increases the internal temperature
• Thermal stress on component terminals
• Charge/discharge rate
• Ambient conditions (temperature
• Mechanical stress
• Vibrations, hot/cold expansion

In addition, the inverter bridge is susceptible to the following:

• Usage beyond its rated operating limit
• Voltage, current, overshoots, inrush
• Other malfunctioning components
• Thermal shock
• Thermal overload
• Extremely cold operating temperature

The Satic Solar Power Perfect Box (SPPB) distributed by Blue Planet LLC is a UL listed energy management system (not a capacitor bank) that is quickly and easily installed at the distribution panel. Some of its primary attributes include:

• Harmonics Filtration – Harmonics can be introduced into the electrical system in many ways including from the grid; from CFL lighting, electrical motors and switching power supplies on the premise; from the PV generators and from solar inverters themselves. Removing these harmonics makes the entire electrical system cleaner and more efficient. Inverter failure has been shown to be directly related to exposure to harmonics. Filtering harmonics will increase longevity of the inverter.
• Phase Correction – Providing phase correction will increase the percentage of power that actually accomplishes real work and produce less heat in motors and devices since there is less reactive power that can be turned into heat. This is true for not only the appliances and devices on premise but also the inverter itself. Less heat also means less potential thermal stress on the inverter and lower power demand.
• Voltage Regulation – Ensuring consistent and level voltage and current is desirable for any electrical system. This includes protecting from surges (even microsurges) that can quickly damage electronics to leveling demand caused by inrush. The SPPB can provide this protection to not only the inverter but also the entire electrical system reducing stress on the system and potential damage to the inverter.
• Electromagnetic Field (EMF) Reduction – Modern electronics and inverters introduce harmonics into electrical systems that result in EMF. There is increasing evidence that exposure to EMF radiation may have serious health effects. Less EMF equates to a healthier environment whether it be a home or business. Third party testing has shown that the SPPB reduces Total Harmonic Distortion (THD) and the related EMF radiation.
• Lower Power Consumption – It only makes sense that if the power supplied is cleaner that it will also be more efficient. That means less power is turned into heat resulting in cooler running and more efficient electrical appliances. This means a longer life for electronics, electrical appliances, motors and inverters.

In summary, the solar inverter is one of the weakest links in any solar energy system and typically needs to be replaced or repaired several times during the lifetime of the system. It seems prudent to include a Satic Solar Power Perfect Box with any solar installation to reduce inverter replacement or repair and maintenance costs as well as to provide a healthier more efficient electrical system.

References:

Craister, D. (2015, January) The Top Five Things That Cause Inverter Failure. Retrieved from: https://www.linkedin.com/pulse/top-five-things-causeinverter-failure-darren-craister

Ireland, B. (2009, April) Module Behavior: Prolonging PV module life by improving inverter maintenance and manufacturing. Electrical Construction and Maintenance. Retrieved from: http://ecmweb.com/ops-amp-maintenance/modulebehavior

Wilkins, J. (2014, November) The top five things that cause inverter failure. Automation.com Retrieved from: http://www.automation.com/automation-news/article/thetop-five-things-that-cause-inverter-failure