Extremely short-duration voltage variations, lasting milliseconds, have become a growing concern among large electricity consumers in Brazil.
According to Abrace Energia, an organization representing energy-intensive industrial consumers, its members perceive that energy quality has been worsening in recent years, both in distribution and transmission networks.
According to Victor Iocca, Director of Electrical Energy at Abrace, a decade ago it was rare for large consumers connected to the main grid to complain about the quality of the energy.
"The main problem is short-duration voltage variations. In many cases, these events are not even measured," he explains.
The result is a type of disruption that is almost invisible from a regulatory standpoint, but with concrete and often severe effects on ongoing industrial processes.
Damage to the industry
Although they last only a few milliseconds, these fluctuations are enough to cause sensitive electronic systems to shut down, halt production lines, and cause losses that extend for hours or even days.
Iocca reports that industrial processes in line are particularly vulnerable. A single failure, for example, can require the shutdown of an entire plant.
Among the sectors most affected are the aluminum, glass, and chemical industries. In the case of aluminum, an abrupt voltage variation can disable electronic systems and cause tanks containing highly dangerous chemicals to overflow, increasing not only economic losses but also human risk.
In the glass industry, even very short interruptions can lead to lost production and, in extreme situations, to the complete destruction of industrial furnaces, costing millions of reais.
Despite their seriousness, these events do not appear in traditional electricity sector statistics. "There is currently no national indicator showing the extent of very short-term variations, neither in transmission nor distribution," points out Iocca. In the executive's opinion, this is a significant gap in Brazilian regulation.
Arrangements
Given this scenario, Abrace has been seeking to bring the issue to the attention of regulators and the ONS (National System Operator), advocating for advancements in how power quality is monitored and regulated.
According to the director, although there has been some progress in distribution — such as the consumer's right to request the installation of quality meters — there are still no regulatory parameters that allow for penalizing utility companies for micro-variations in voltage.
In broadcasting, the situation is considered even more worrying because there are no rules for investigating this type of event. According to the organization, this creates a disconnect between the real impact felt by consumers and how the quality of the service is officially evaluated.
Studies commissioned by Abrace, including those conducted by academic experts, point to significant gaps in the current regulatory framework.
Mitigation
While regulation is stalled, many companies have been forced to seek internal solutions to reduce their vulnerability. One strategy is the reassessment of electrical protections, making systems more tolerant to very rapid fluctuations.
In practical terms, this means adjusting equipment so that it does not automatically shut down in response to variations of only a few electrical cycles. Another increasingly considered alternative is the use of cogeneration and "island" operation.
In this model, industrial plants with their own power generation systems operate independently of the public grid when an external failure occurs, keeping production running. More recently, investment in energy storage systems, especially battery banks, has been gaining ground.
Initially adopted for economic reasons, as a response to tariff signals, these solutions are also being incorporated as tools for protecting power quality. "Batteries have a very fast response and make sense when you consider the cost of losing hours or days of production because of a millisecond variation," notes Iocca.
Still, he acknowledges that there are limits. If the network quality in a given region deteriorates structurally, there is no internal solution capable of completely eliminating the problem.
What does the regulation say?
In Brazil, the responsibility for the quality of the energy supplied lies with the distributors, and the rules are defined by... ANEEL (National Electric Energy Agency), mainly through PRODIST (Distribution Procedures). The regulation distinguishes two pillars: product quality and service quality.
Product quality refers to the characteristics of the electricity delivered, such as voltage levels, frequency, and harmonic distortions. Distributors must maintain the voltage within ranges classified as adequate, poor, or critical, in addition to ensuring a frequency close to 60 Hz.
Service quality, on the other hand, is related to the continuity of supply and is measured by indicators such as DIC, FIC, and DMIC, which assess the duration and frequency of interruptions.
When these limits are exceeded, the consumer is entitled to automatic financial compensation on their electricity bill. The regulation also provides for reimbursement for damage to equipment caused by network failures.
However, as Abrace points out, these standards do not adequately address very short-term variations, which are precisely those that most affect sensitive industrial processes.
According to the organization, this is the next challenge for the Brazilian electricity sector: aligning regulation with the technological and operational realities of modern loads, otherwise the competitiveness of the national industry will be compromised.
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An answer
Unfortunately, companies that suffer from this will have to adopt their own solutions such as uninterruptible power supplies (UPS) or online inverters. I worked at a company where the solution was to adopt a 10 kW inverter and a 125V DC battery bank (with rectifier). The inverter always worked by assuming the load, making any variation in the grid irrelevant. It was a Saft Nife inverter that I liked because it was all analog, no processors.