力率

学術機関の配電システムの電力品質 — スルタン・カブース大学

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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システム, 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% へ 0.702% in a medium-unbalance scenario, but increased it from 0.787% へ 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, インドネシア. 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, VFDは, imaging equipment.

アメージングインターナショナル – 発電機と非線形負荷: 高調波緩和によりオーバーサイジング要件を排除する方法

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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.

アメージングインターナショナル – パッシブ vs. データセンターのアクティブ高調波フィルター: フィールドの比較

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パッシブ vs. 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.

アメージングインターナショナル – 都市下水処理場におけるターボブロワーの効率と高調波適合性

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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.

アメージングインターナショナル – 遠隔地油井での高調波制御: 12 パルスのコストで 18 パルスより優れたパフォーマンス

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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.

アメージングインターナショナル – 発電機から供給されるモーター制御センターの高調波緩和: 天然ガス甘味プラント

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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.

アメージングインターナショナル – 高調波の軽減と発電機の適正サイズ化 – パイプラインポンプ場のケーススタディ

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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.

電力品質調査の実践事例 (オリーブの木, ホセ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, 高調波歪み, 電圧不平衡, and feeder transfer risk. A foundational industrial PQ assessment methodology paper. The PDF is available for download from the IPQDF library.

ハーモニクスケーススタディ

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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.

VFD上のハーモニクス軽減

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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.

高調波発生, 伝播と非線形負荷でパージテクニック

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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.

でも、高調波共振- Unsual問題

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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.

物流ネットワーク内の2つの共振ポイントを緩和するために高調波フィルタの設計

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South African distribution network with two resonant points at different harmonic orders — a single-tuned filter addresses one resonance but can amplify the other. Case from Cape Peninsula University of Technology documents the filter design process for a network with two resonant frequencies, requiring a carefully detuned double-tuned filter to address both simultaneously.

コンデンサの故障解析 (イートン)

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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.

電圧と高調波電流 (ジョン·ワイリー & ソンス)

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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は、問題を緩和する高調波食料生産を確保 (コムシス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は、水処理プラントの出力を増加させる 30% (コムシス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.

力率補償コンデンサの切り替え (日置)

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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.

照明バラスト評価 (まぐれ当たり)

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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 週エネルギー調査 (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, 力率, and energy use patterns to establish a fair cost-recovery billing methodology for the concession operator.

繊維産業の評価 (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 最小. 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システムユーティリティ変電所のメーカーと他のユーザーのために電圧低下の問題を解決し

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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.

液体と気体ポンプ/パイプラインアプリケーション (アメリカの超伝導)

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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, 高調波, 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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