# Photovoltaic-Related “Black Swan” Hypothesis for Electric Power System: Phenomenology, Simulations, Experiences, and Prevention

## TL;DR

The paper explores how high renewable energy use, especially photovoltaics, can lead to rare but severe blackouts in power systems.

## Contribution

It introduces a new hypothesis linking photovoltaic inverter control to potential massive blackouts.

## Key findings

- High penetration of renewables can cause stability issues leading to blackouts.
- Simulations show that photovoltaic inverters may contribute to rare, high-impact blackout events.
- Energy communities are proposed as an alternative to reduce system vulnerability.

## Abstract

Electric power systems with high penetration of renewables are highly exposed to stability issues. This problem was less important 20 or 30 years ago because electric power systems were dominated by synchronous generators. Since then, the percentage of renewables in the total generated power has been neglected. Systems were stable because of the properties of electric machines. Now, the properties of systems are highly influenced by the software of power inverters, especially photovoltaic sources (PV inverters). In this study, simulations and analysis are introduced to explain the lack of stability and series of events that could cause blackouts. These rare, high-impact events are sometimes called “black swans”.

What are the main findings?
A possible explanation for recent massive blackouts is offered.Simulations were conducted in order to support the hypothesis.

A possible explanation for recent massive blackouts is offered.

Simulations were conducted in order to support the hypothesis.

What are the implications of the main findings?
Events prior to massive blackouts in modern power systems could be detected.Different configurations of power systems were compared in order to decrease the vulnerability of systems with high penetration of renewables, mainly photovoltaic sources.An alternative to large electric power systems in the form of energy communities is put forth.

Events prior to massive blackouts in modern power systems could be detected.

Different configurations of power systems were compared in order to decrease the vulnerability of systems with high penetration of renewables, mainly photovoltaic sources.

An alternative to large electric power systems in the form of energy communities is put forth.

Several blackouts have recently occurred in Europe and elsewhere. Blackouts are mostly the consequence of a series of events rather than a single event. Their intensity and frequency could be related to the stronger penetration of renewables into electric power systems. Although many different renewable power units may be installed, they all have some basic properties: their power is not consistent, and power inverters are used to connect renewables to electric power systems. Photovoltaic systems are the most typical representative of this large group of power sources. These devices have become more sophisticated over the past few years, allowing for the precise control of large photovoltaic fields. In this situation, all power converters act as one. This means that they could be turned on and off during short intervals. Furthermore, their power factor could be independently adjusted. These functions are desirable for small systems; however, their implications for stability at a larger scale are usually not considered. In this study, the stability issues of a system under the high penetration of renewables and a unique control system are investigated. The most prominent case of this influence is a high-impact rare (HR) event, also known as a “black swan”, which could cause a massive blackout in an electric power system.