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Sometimes, the amount of solar power reaching the panels can be too high, and as a result the system receives more electricity than it can safely handle. These fluctuations can cause the inverter to shut down, in order to protect both the equipment and the power grid, as the majority of regulations governing the connection of these types of system to the grid require solar inverters to shut down when their voltage exceeds certain limits. In unstable networks, this can cause unwanted shutdowns of the photovoltaic installation. If the inverter shuts down, it no longer makes use of solar power, which can have a big impact not only economically, but also in terms of efficiency.

Royal Decree 1699/2011 establishes a series of requirements and parameters for inverters, such as voltage ranges, operating frequencies, maximum and minimum capacities, and efficiency levels. It also stipulates that inverters must be automatically disconnected from the grid – which they generally do by switching themselves off – when the following criteria are not met, in order to ensure the safety of the system and the power grid.

Parameter: Overvoltage – phase 1

Protection threshold: +10%

Maximum reaction time: 1.5 s

Parameter: Overvoltage – phase 2

Protection threshold: 15%

Maximum reaction time: 0.2 s

Parameter: Minimum voltage

Protection threshold: -15%

Maximum reaction time: 1.5 s

Parameter: Maximum frequency

Protection threshold: 50.5 Hz

Maximum reaction time: 0.5 s

Parameter: Minimum frequency

Protection threshold: 48 Hz

Maximum reaction time: 3 s

Given that, in the vast majority of cases, the excess energy generated is injected into the grid (in exchange for financial compensation), bidirectional equipment is therefore essential. The regulators monitor the grid voltage at all times, and in line with said voltage they can provide quick and precise voltage jumps within the short reaction times that are stipulated by the vast majority of national grids. Moreover, they also help to extend the useful life of the equipment and ensure a more stable delivery of energy.

The energy produced by photovoltaic installations can be self-consumed, stored, or injected into the grid. When the regulator detects that the voltage is too high, it automatically adjusts the amount of electricity that reaches the inverter, in order to avoid damaging it or causing a shutdown. Salicru offers three solutions that can tackle this issue. The VR EQX range is designed chiefly for photovoltaic installations that operate on a self-consumption basis and are connected to the grid, and enables such systems to remain viable regardless of the brand of inverter they use. The RE3 series comprises electronic stabilisers that have an entirely static structure and stand out for their high performance, speed of response and accuracy of output. The models in this range are available in single- and three-phase configurations and with power ratings ranging from 300 VA up to 250 kVA. Lastly, the Emi3 series of servomotor voltage stabilisers is available in configurations ranging from 5 kVA up to 2,500 kVA.