[Public Voices] Infrastructure Performance Improvements Needed to Prevent Low-Voltage Risks in Solar Power

When setting South Korea's greenhouse gas reduction target for 2030, a 40% reduction compared to 2018 was declared, which corresponds to an annual reduction rate of 4.17%, the highest level among all countries worldwide. To achieve this figure, it is necessary to significantly increase eco-friendly renewable energy sources such as solar and wind power. The 10th Basic Plan for Electricity Supply and Demand reflects this by planning to expand the share of renewable energy generation to 21.6% by 2030 and to 30.6% by 2036.

It is well known that to achieve carbon neutrality by 2050, the installation and utilization of solar and wind power must be expanded. However, simply installing solar and wind power generation facilities is not enough. Since solar and wind are natural energy sources, their generation is intermittent and unpredictable. Therefore, various auxiliary devices must be installed alongside the generation facilities. In particular, to sustainably connect to the power grid, an inverter (power conversion device) with stable performance that links DC-based solar power generators to the AC power grid is essential. If the inverter does not perform properly, it may fail to function during unexpected low-voltage situations in the power system, causing it to trip first and thereby increasing the risk to the power grid. This risk is especially high in areas with large-scale solar installations.

For example, in Jeju Island in August 2021, a transmission line fault caused a dangerous situation where 145 MW of renewable energy generation was massively disconnected. If a properly functioning inverter had been installed, the power grid reliability could have been maintained for an appropriate period. Additionally, in December 2022, an accident in one phase of the three-phase system at Gwangyang Substation caused a sudden disconnection of a large-scale 450 MW solar power facility nearby, which was ultimately due to the lack of inverters meeting regulatory performance standards. This indicates that risks are not insignificant even inland. If inverters with proper functions and standards had been in place, such large-scale disconnections would not have occurred, and the power grid could have been maintained stably. If these issues are not addressed in the future, the risk of widespread blackouts spreading across inland solar power installations cannot be ruled out.

It is necessary to move away from the practice of installing low-cost Chinese products and develop domestic high-performance inverter standards that meet international standards, establishing a stable inverter market based on these standards. Installing high-performance inverters differentiated from Chinese products simultaneously with solar power generation facilities should be recognized as an essential measure to reduce blackout risks even under low-voltage and low-frequency conditions. However, currently, the installation rate of stable inverters with continuous low-voltage operation performance in South Korea is only 1.5%. Since there were no appropriate standards for inverters at the time of installation, many of the low-cost inverters installed previously are malfunctioning or underperforming and fail to perform their intended functions. These inverter issues have been warned by experts since the point when renewable energy expansion was aimed at achieving carbon neutrality. Although additional technical infrastructure measures should have been prepared as solar power increased, it is a positive direction that the government is now stepping in to support improving or replacing inverter performance.

The lesson learned from the increasingly complex and multifaceted power market is that problems cannot be solved by installation alone, regardless of the power source. To avoid repeating mistakes, market systems designed to provide appropriate compensation simultaneously with installation, infrastructure development, and proper regulatory governance must be implemented to enable stable power system operation. It is time for the government, companies, and experts to join forces to successfully carry out inverter performance improvement and replacement projects, which play a crucial role in the power market.

Cho Hongjong, Professor at Dankook University