ONS requests update of photovoltaic inverters

O ONS (National Electrical System Operator), through ONS Letter No. 2143/2022, reported the progress of the request to update inverter protection function settings of distributed photovoltaic microgeneration in Brazil.

The process began with the update of Inmetro Ordinance nº 004/2011, current Inmetro Ordinance No. 140/2022, in order to incorporate new supportability/immunity requirements and new recommendations for adjusting the frequency and voltage protection functions of the equipment.

Afterwards, the Operator spoke with manufacturers to understand how inverters already sold can be updated. In this sense, the meeting, which took place during the Intersolar, was attended by several companies that expressed concern about the technical parameters of electricity distributors.

A ANEEL (National Electric Energy Agency) was notified and sent Circular Letter No. 0012/2022-SRD/ to the distributors.ANEEL, in order to reap benefits regarding the update of protection functions for safe adjustments and in line with the new Inmetro Ordinance.

The distributors' responses, according to the ONS, were to agree with the correction of unsafe adjustments of distributed microgeneration inverters, as long as the action did not imply costs for the distributors and with the manufacturers' guarantee that the ABNT NBR IEC 62116 standard ( Anti-islanding protection test procedures) continue to be met, that is, that anti-islanding techniques continue to guarantee the detection of islanding within 2 s, as defined in the ABNT NBR 16149 standard itself.

“Therefore, we request that manufacturers, on a voluntary basis, remotely update as many inverters as possible (installed and in stock) with unsafe adjustments of the frequency and undervoltage protection functions to the settings contained in the Ordinance Inmetro nº 140/2022”, they communicated.

The Operator requests that, by December 22nd, manufacturers forward the amount in MW and the percentage of inverters in operation with their respective protection adjustments employed by each manufacturer, such as the forecast of the amount of inverters that can be readjusted accordingly. remotely to the new parameters.

It also requests, by January 23, 2023, the final diagnosis from manufacturers in relation to the effectiveness of such actions, highlighting the amount, in MW, of inverters that were readjusted, the deadlines for complying with the new INMETRO ordinance for new products and the current situation of inverters in stock that will still be sold without full compliance with this ordinance.

How are manufacturers responding to the request?

A PHB Solar informed the Canal Solar which has already started working on updates to its inverters. “We are doing it gradually, as changing the firmware to meet the requirements must be well tested.”

“We emphasize that no inverter will have its operation compromised in any way, as the changes are to parameters that do not alter the way it operates under normal working conditions,” the company reported in a note.

Already Solis announced that it is putting together an action plan to respond to the request and Fronius from Brazil, according to Ariel Martins, technical coordinator of the company's Solar Energy unit, stated that they are committed and are working to carry out all updates related to the inverters' protection functions as quickly as possible.

“We hope that with the changes planned and implemented, as proposed, we will be able to avoid possible major problems of disconnection and blackout of distributed generation in Brazil, as has been possible to observe throughout history in other countries”, he reported.

“The expectation is that new update firmwares will be launched in December this year, in order to guarantee and bring the best performance and security to photovoltaic systems connected to the grid”, concluded Martins.