功率因数

Power Quality in an Academic Institution’s Electrical Distribution System — Sultan Qaboos University

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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% 至 0.702% in a medium-unbalance scenario, but increased it from 0.787% 至 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, 印尼. 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: 开关电源, UPS, 变频驱动器, imaging equipment.

惊人国际 – Generators and Nonlinear Loads: How Harmonic Mitigation Eliminates the Oversizing Requirement

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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.

惊人国际 – Turbo Blower Efficiency and Harmonic Compliance at a Municipal Wastewater Plant

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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.

惊人国际 – Harmonic Control at a Remote Oil Well: Better Than 18-Pulse Performance at 12-Pulse Cost

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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.

惊人国际 – Harmonic Mitigation for a Generator-Fed Motor Control Centre: Natural Gas Sweetening Plant

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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.

惊人国际 – Harmonic Mitigation and Generator Rightsizing – A Pipeline Pumping Station Case Study

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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.

电能质量研究的一个实际案例 (橄榄树, 何塞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, 谐波失真, 电压不平衡, and feeder transfer risk. A foundational industrial PQ assessment methodology paper. The PDF is available for download from the IPQDF library.

谐波案例研究

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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.

变频器谐波缓解

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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.

谐波发生, 在非线性负载的传播和清除技术

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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.

偶次谐波共振- 一个Unsual问题

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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.

缓解两个谐振点的分销网络的谐波滤波器设计

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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.

电容器故障分析 (伊顿公司)

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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.

电压和电流谐波 (约翰·威利 & 儿子)

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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.

缓解谐波ADF食品安全生产 (Comsys的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提高水厂输出 30% (Comsys的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.

电能质量改善与节能纺织工业用固态谐波滤波器

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Solid-state harmonic filter application in a textile manufacturing plant — reducing harmonic current injection from VFD-driven machinery. The filter also improved power factor, reducing reactive power charges from the utility. Available as an external linked technical document.

开关的功率因数补偿电容器 (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.

照明镇流器评价 (吸虫)

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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 周能源调查 (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, 功率因数, and energy use patterns to establish a fair cost-recovery billing methodology for the concession operator.

数据中心监控使用喝采需求响应性能 (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.

纺织行业评价 (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系统解决了制造商和其他用户的实用变电站的电压暂降问题

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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.

液体和气体泵/管道应用 (美国超导公司)

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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, 谐波, 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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