Fator de Potência

Qualidade de energia no sistema de distribuição elétrica de uma instituição acadêmica — Universidade Sultan Qaboos

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Full campus PQ audit at Sultan Qaboos University, Oman — 33 kV/11 kV/415 V distribution system. Non-linear loads: PV inverters, UPS systems, VFD chillers, and hundreds of switch-mode power supplies in computer labs. THDI ranged from 2–10%, TDD from 2–8% across measurement points. Main substations compliant with IEEE 519 due to harmonic aggregation cancellation — but individual buildings exceeded 8% at peak load. Key lesson: the THD vs. TDD distinction prevents false alarms. The study establishes a pre-DER baseline before planned large-scale PV integration.

Voltage Unbalance in DER-Rich Networks — When Solar PV Helps and When It Doesn’t

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Single-phase PV panels can either worsen or improve voltage unbalance on LV feeders — depending entirely on the existing load phase distribution. UPM Madrid analysis on the IEEE European LV Test Feeder shows PV reduced mean VUF from 1.255% para 0.702% in a medium-unbalance scenario, but increased it from 0.787% para 0.963% in a low-unbalance scenario. Equally important: IEEE PVUR1 and PVUR2 indices can overestimate the true VUF by a factor of 10–16× in DER-rich networks — the CIGRE index is the only reliable alternative that requires only line voltage magnitudes.

Data-Driven Power Quality Evaluation in a Hospital Electrical System

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Full PQ audit at University of Lampung Hospital, Indonésia. Voltage and frequency compliant at the meter — but current TDD exceeded IEEE 519 limits many times over, voltage unbalance non-compliant, power factor lagging. All problems originated inside the facility from non-linear loads: SMPS, UPS, ACV, imaging equipment.

Internacional incrível – Geradores e cargas não lineares: Como a mitigação harmônica elimina a exigência de superdimensionamento

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Mirus International demonstrates that generators feeding non-linear loads must be derated or oversized to prevent excessive voltage distortion — standard practice adds 20–25% generator capacity. The Wide Spectrum Filter (Lineator) eliminates the oversizing requirement by reducing harmonic current drawn from the generator, enabling right-sized generator selection and significant capital and fuel savings.

Internacional incrível – Passivo versus. Filtro Harmônico Ativo em um Data Center: Uma comparação de campo

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Passivo versus. active harmonic filter comparison at a New Jersey data centre: active filter failed repeatedly at this site, passive Lineator filter installed on the same VFD loads achieved THID below 5% — well within IEEE 519 — and has operated without failure for years. The case presents measured data from both technologies on the same equipment at the same site.

Internacional incrível – Eficiência do turbo soprador e conformidade harmônica em uma estação municipal de águas residuais

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Municipal wastewater plant with turbo blower VFDs: total harmonic current distortion exceeded IEEE 519 limits at the point of common coupling. Three-party solution — utility, municipality, and Mirus — achieved ITDD (Individual Total Demand Distortion) compliance using Lineator filters. Efficiency improved and the plant qualified for utility incentives unavailable under non-compliant harmonic conditions.

Internacional incrível – Controle Harmônico em um Poço de Petróleo Remoto: Desempenho melhor que 18 pulsos com custo de 12 pulsos

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Remote oil well site with a single-drive VFD application: multi-pulse transformer approaches were impractical at this location. Mirus Lineator passive filter achieved better than 18-pulse harmonic performance at 12-pulse cost — measured THID below 5% at the drive input. The case demonstrates that passive harmonic filters can outperform multi-pulse transformers in single-drive, isolated applications.

Internacional incrível – Mitigação Harmônica para um Centro de Controle de Motor Alimentado por Gerador: Planta de adoçante de gás natural

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Natural gas sweetening plant with a generator-fed motor control centre: the generator’s high source impedance amplified harmonic voltage distortion from VFD loads to levels that caused control system malfunctions. Mirus filter selection had to account for the generator impedance characteristics rather than infinite bus assumptions — a common oversight in generator-fed harmonic filter design.

Internacional incrível – Mitigação harmônica e redimensionamento do gerador – Um estudo de caso de estação de bombeamento de oleoduto

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Pipeline pumping station with generator-fed VFDs: harmonic current from the drives caused the generator to be significantly oversized — adding capital cost and reducing fuel efficiency. Mirus sinewave filter reduced harmonic current to allow generator rightsizing, improving fuel efficiency and reducing the generator procurement cost. Field results show measured harmonic distortion and generator loading before and after.

Um caso prático de Estudo de Qualidade de Energia (Oliveira, Jose C.)

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IEEE conference paper by Prof. José Carlos de Oliveira (Federal University of Uberlândia) — site measurements at a Brazilian textile factory. Four-parameter framework: voltage profile, distorções harmônicas, desequilíbrio de tensão, and feeder transfer risk. A foundational industrial PQ assessment methodology paper. The PDF is available for download from the IPQDF library.

Harmônicos Estudo de Caso

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A major food processing and distribution centre in Dortmund, Germany — 100,000 m² facility — experienced production disruptions and equipment malfunctions from harmonic distortion generated by VFDs in the highly automated facility. Active harmonic filter installation reduced current THD and eliminated the production disruptions. Before/after measurements confirm compliance with German grid code.

Harmônicos Mitigação de VFD

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GRYAAB Gothenburg sewage works used variable-speed pumps to process wastewater — but VFD harmonic currents limited pump output to below the theoretical maximum. Active harmonic filter installation optimised VFD electrical behaviour, enabling 30% more throughput during peak demand periods. Energy savings were a secondary benefit — the primary gain was process capacity.

Harmônicos Generation, Propagação e purga Técnicas de cargas não-lineares

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Saudi Arabia academic review of harmonic generation mechanisms, propagation paths, and mitigation techniques for non-linear loads — covering passive filters, active filters, hybrid approaches, and multi-pulse converters. Provides theoretical grounding for harmonic mitigation selection, with worked examples for different industrial load types. King Saud University publication.

Mesmo Ressonância Harmônica- um problema Unsual

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Chemical plant using large static converters for electrochemical processes experienced repeated harmonic filter failures. Investigation revealed even harmonic resonance — an unusual problem typically found only in uncontrolled rectifiers or systems with DC offset. The even harmonics were caused by asymmetrical firing of the converter’s thyristors, creating 2nd and 4th harmonic currents that the filter was not designed to handle.

Análise de falha de capacitor (Eaton)

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A steel processing plant experienced unexplained capacitor failures and fuse operations in an automatically switched capacitor bank. Eaton Engineering investigation revealed harmonic resonance between the capacitor bank and system impedance — at a specific harmonic order, the impedance was amplified, overloading the capacitors well beyond their rated capability. Classic harmonic-capacitor resonance case with full analytical solution.

Harmônicas de tensão e corrente (John Wiley & Filhos)

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Six-pulse converter transformer selection and rating when harmonic spectrum is known. John Wiley Handbook of Power Quality chapter covers K-factor calculation, additional loss estimation, and de-rating methodology for transformers feeding rectifier loads. Provides the calculation procedure engineers need to correctly specify transformers for non-linear load environments.

ADF Produção de Alimentos Seguro por Harmonics atenuantes (Comsys AB)

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REWE Dortmund distribution centre — rebuilt and expanded butcher facility with high VFD density — experienced harmonics causing machinery malfunctions. Comsys ADF active harmonic filter brought current THD within acceptable limits and eliminated the machinery problems. Duplicate of case 2336 with Comsys branding — same REWE Dortmund facility, same solution.

ADF água aumenta saída pela Estação de Tratamento de 30% (Comsys AB)

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GRYAAB Ryaverket sewage works in Gothenburg — one of Scandinavia’s largest treatment plants — used VFD-controlled pumps. Comsys ADF active harmonic filter optimised VFD electrical behaviour, allowing 30% more fluid processing capacity during peak periods with simultaneous energy savings. Duplicate of case 2334 with Comsys branding — same Gothenburg facility.

Mudar de um capacitor de compensação do fator de potência (HIOKI)

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Equipment power supply damage traced to transient overvoltages caused by power factor correction capacitor switching within the facility. The switching waveform propagated through the LV circuit without filtering and combined with impulse transients at switch-off, creating damaging voltage peaks. A filtering device at the capacitor bank would have prevented the equipment failures.

Iluminação de lastro de avaliação (Casualidade)

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Lighting maintenance in large facilities is a major cost — especially with high ceilings requiring personnel lifts. This Fluke case study evaluates whether replacing existing ballasts with electronic ballasts reduces maintenance costs enough to justify the capital investment, using measured power factor, harmonic content, and lamp life data to build the economic case.

2 Energy Survey semana (Dranetz)

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Two-week energy survey at a New Jersey swim club — measuring electrical demand and energy consumption of a food concession operation whose utility costs the club wants to recover. Dranetz monitoring captures peak demand, power factor, and energy use patterns to establish a fair cost-recovery billing methodology for the concession operator.

Data Center uses Encore to monitor Demand Response Performance (Dranetz)

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A 1.2M sq ft New Jersey data centre participating in a demand response program used backup generators to reduce 7 MW of load. Dranetz Encore Series was installed on four 2.5 MW turbines to provide real-time generator performance monitoring — replacing unreliable utility KYZ pulse metering with direct power measurement.

Avaliação da Indústria Têxtil (Dranetz)

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Paper mill voltage sag costs $250,000 per event. A 5-cycle interruption at a glass plant costs $200,000 minimum. Duke Energy and Clemson University developed the Webstand portable process simulator to establish the immunity boundary — the voltage sag depth and duration at which the textile or film production process trips — before production losses occur rather than after.

PQ-SVC Sistema resolve problemas afundamento de tensão para fabricante e outros usuários de Subestação Utility

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A manufacturer of muffler hangers added large automated welders — producing a 12-cycle, 4% voltage sag at 30-second intervals that caused utility complaints from all circuits at the same substation. The utility faced an impossible choice: lose the 200-employee manufacturer or continue receiving complaints from all other customers. American Superconductor’s PQ-SVC resolved both problems simultaneously.

Líquidos e Gás Bomba / Pipeline Aplicações (American Superconductor)

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Pipeline pump stations are moving to larger motors — 4160V in the 2,000–4,000 HP range, 15kV-class at 8,000–15,000 HP — creating significant flicker, harmônico, and reactive power management challenges. American Superconductor’s PQ-SVC system provides dynamic reactive compensation enabling larger motor sizes at existing substations without requiring substation upgrades.

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