Short-circuit protections in photovoltaic plants: Ensuring safety and efficiency

The proliferation of photovoltaic plants for the generation of clean energy has transformed the global energy landscape. However, as the use of this technology increases, so does the need to ensure its operational safety. One of the most critical risks in these facilities is the short circuit, an event that can endanger both the integrity of the equipment and the safety of people. Therefore, it is essential to implement effective protection systems to mitigate these risks and ensure the optimal operation of photovoltaic plants.

1. Understanding the short circuit in photovoltaic systems

A short circuit in a photovoltaic plant occurs when there is a direct connection between two points in the circuit with different electrical potentials, creating a low-resistance path for the current. In photovoltaic systems, this can be caused by various factors, such as failures in solar modules, damage to cables, or problems with inverters. These events can result in excessive current that can damage electrical components, cause fires, and reduce the overall efficiency of the system.

2. Protection devices: Circuit breakers and fuses

One of the first levels of protection against short circuits are circuit breakers and fuses. These devices will act once the fault has occurred, interrupting the flow of current and therefore isolating the part of the installation where the short circuit has occurred.

Circuit breakers, designed to internally interrupt the flow of current when they detect an excess, can be found in both the alternating current (AC) and direct current (DC) parts of photovoltaic systems. They are based on internal contacts that open and close, thus being able to isolate the circuit or close it again. These devices are crucial to prevent damage to solar modules and cables, as well as to prevent fires.

Fuses, on the other hand, are protective elements that blow when the current exceeds a predetermined level, thus disconnecting the circuit. They are mainly found in the DC part of the plant and, although they require replacement after each short circuit event, they are low-priced and effective in protecting both modules and inverters.

The correct design and choice of the circuit breakers and fuses that will be found in a photovoltaic plant is essential for the protection and safety of the installation. These elements must be coordinated with each other to ensure that they will always act when a fault such as a short circuit happens, always isolating the smallest possible part of the installation. Likewise, their design must ensure that they will not act if the short circuit does not occur, allowing the normal operation of the plant.

3. Specific protections in inverters

Inverters are key components in a photovoltaic plant, as they convert the direct current (DC) generated by the photovoltaic modules into alternating current (AC) usable in the electrical grid.

Inverters are designed to detect and respond to short circuits in the input circuit (DC) or in the output circuit (AC). When a short circuit is detected, the inverter acts quickly to disconnect the affected circuit and prevent damage. This protection is implemented by means of internal circuit breakers and protection relays that interrupt the flow of current when a short circuit is detected, minimizing the risk of damage to the inverter and other system components.

4. Protection against electric arcs

One of the consequences of short circuits is that they can lead to the appearance of electric arcs. These are high-energy discharges that can generate extremely high temperatures and cause fires. Therefore, photovoltaic plants must have a protection system against the appearance of these electric arcs.

Electric arc detectors (AED) are devices designed to identify the presence of electric arcs in real time. These detectors work by analyzing electrical signals and current wave characteristics. When they detect patterns that indicate an electric arc, they send alert signals to the circuit breakers and protection relays so that they automatically interrupt the flow of current in the affected circuit, preventing the electric arc from causing further damage.

5. Regular Inspection and Maintenance

Preventive maintenance and regular inspection are essential to maintaining the integrity of protection systems. Periodic inspection of cables, connectors, and protection devices ensures that any signs of wear or damage are detected and corrected before they cause a short circuit.

Calibrating and testing circuit breakers ensures that they operate correctly when needed. In addition, maintaining and updating inverter firmware improves system performance and safety.

Also, keeping a detailed record of all preventive maintenance activities is crucial. Key tasks in this regard include documenting all inspections, repairs, and replacements performed. Include information on dates, specific details of tasks performed, and any relevant findings through maintenance history, note system performance during overhauls and any anomalies detected by recording data such as power output, module efficiency, and inverter readings in performance logs, and document any significant incidents such as system failures, damage, or outages including details on the causes, actions taken to resolve the issues, and measures implemented to prevent recurrence in incident reports.

6. Integration of advanced technologies

Technology is advancing quickly in the field of renewable energy, and protection systems are no exception. The integration of real-time monitoring systems (remote monitoring, predictive analysis, automatic alerts) makes it possible to detect anomalies and prevent the occurrence of short circuits, improving response capacity and reducing downtime. These systems can provide automatic alerts and accurate diagnostics, facilitating rapid and effective intervention.

The integration of advanced technologies also improves preventive and predictive maintenance strategies by using inspection with drones equipped with thermal cameras that can perform aerial inspections to identify damage to the system, using Internet-connected (IoT) sensors that monitor the status of critical components, and using advanced data analysis tools that allow large volumes of information to be interpreted to predict failures, schedule maintenance, and optimize overall system performance.

Conclusion

Protection against short circuits is essential to ensure the safety and performance of photovoltaic plants. Implementing a combination of protection devices, performing regular maintenance, and taking advantage of advanced technologies can help minimize the risks associated with short circuits. By adopting these measures, it is possible to ensure that photovoltaic installations continue to operate safely and efficiently, contributing to a more sustainable and reliable future in energy generation.