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LOW HARMONICS SOLUTIONS FREEMAQ SERIES February 2014 1 Harmonic Causes 2 Harmonic Effects 3 Useful Formulae 4 EMC – THD Standards 5 PE Low Harmonics Techn. 6 SD700FA AHF HARMONICS CAUSES Three-phase loads: n = (k·6 ± 1): 5, 7, 11, 13, 21, …. • Variable speed drives, rectifiers, Electrical arcfurnaces lifts, … • Do not appears tripleN harmonics. • 3 wires AHF cancellate harmonics Single-phase loads: TripleN & n = (k·6 ± 1): 3, 5, 7, 9, 11, 13, 15 … • PC’s, faxes, dimmers, LED lighting, phone chargers, Arc welding machines, etc… • Produce high neutral currents • TripleN harmonics are cancelled with 4 wires AHF Where: k = 1, 2, 3, 4, 5... HARMONICS EFFECTS Power factor reduction. Losses and inefficiency of the electrical system. Conductor losses and transformer overheating (skin effect) Damage to capacitors and resonance. (High frequency current flow through low impedance paths overloading capacitors) Transformer and neutral conductor overload due to excessive zero-phase currents Motor Overheating. Negative rotation sequences in motors Nuisance tripping of protections ( fuses, circuit breakers, relays, etc..) Failure of stand-by diesel generating sets Voltage RMS Current Apparent Power S= V ·I USEFUL FORMULAE Displacement Power Factor (cos ) 𝑃 (𝑘𝑊) 𝐷𝑃𝐹 = 𝑐𝑜𝑠 𝜑 = 𝑆 (𝑘𝑉𝐴) Total Harmonic current Distortion THDi (%) 𝑇𝐻𝐷 = 𝑛=∞ 2 𝑛=2 𝐼𝑛 𝐼1 Power factor (PF) 𝑃𝐹 = 1 1 + 𝑇𝐻𝐷𝐼 2 · 𝑐𝑜𝑠 𝜑 = Apparent power 𝑆𝑇 = 𝑃2 + 𝑄 2 + 𝐷 2 𝐼50𝐻𝑧 · 𝑐𝑜𝑠 𝜑 𝐼𝑟𝑚𝑠 USEFUL FORMULAE Utility transformer S (kVA), Zout (%), Vout (V) Zsc Main Feeder L (m), Wire size (mm 2), Material (Cu or Al), Conductors (#) PCC Zt User transformer S (kVA), Zout (%), Vout (V) IPC1 Zf’ IPC1 Distribution Feeders L (m), Wire size Conductors (#) (mm 2), Material (Cu or Al), Zf2’ Zf2’’ Zf2’’’ IPC2 Non- Linear Loads IPC2 P (kW), H (%), cos φ Zf3’ Linear Loads P (kW), Cos φ IPC3 IPC3 Zf4’ PCC: Point of common coupling IPC Internal point of coupling Zf4’’ Zf4’’’ THDu levels evolution Private Grid THDi levels evolution Public Grid PCC ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION EMC Electromagnetic Compatibility EMS Electromagnetic Susceptibility Amplitude ENVIRONMENT CLASS EMI Electromagnetic Interference Device Immunity level Minimum Immunity level COMPATIBILITY MARGIN Maximum Emission level Device emission level Frequency spectrum ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION EMC Electromagnetic Compatibility EMI Electromagnetic Interference EMS Electromagnetic Susceptibility Low frequency Medium Frecuency F <150 kHz 150 kHz< f < 30MHz THD Flicker Conduced High Frecuency f > 30MHz Radiated IEC61800-3 Radio Frequency Conduced Radiated Surges Electrical fast transients Electrostatic discharges THD Voltage dips and interruptions ELECTROMAGNETIC COMPATIBILITY (EMC) | STANDARDS CE marking for variable speed drive requires compliance with directive EMC 2004/108/CE EMC 2004/108/CE IEC61800-3 EMC 2004/108/CE requires compliance with standard IEC61800-3 IEC61800-3 states that the manufacturer shall provide the current harmonic level under certain conditions. THDv ¿Compatibility levels? IEC61000-2-2 IEC61000-2-4 IEC61000-2-2: Public Low Voltage Power Supply Systems IEC61000-2-4: Industrial and nonpublic networks. Individual VHD and THDv (%) depending on the 3 environmetal class defined IEC61000-3-4 IEC61000-3-12 Public networks up to 600V THD and PWHD up to: IEC61000-3-4 <16A IEC61000-3-12 < 75A IEEE519 - 1992 THDi Recomended practives and requirements for harmonic control in Electrical Power Systems. Individual VHD and THDv (%) depending on Isc/IL Individual CHD and THDI (%) depending on Isc/IL ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-2-4 CLASS CLASS 1 CLASS 2 CLASS 3 DESCRIPTION THDv (%) Location where equipment that is very sensitive to disturbance. This class applies to protected feeders and has compatibility levels that are lower than the level of the public supply system 5% This class generally applies to PCCs (Points of Common Coupling) with the public supply system and to IPCs (Internal Points of Coupling) with industrial or other private supply systems. 8% This class applies only to IPCs (Internal Points of Coupling) in industrial environments. It has higher compatibility levels for some disturbance variables than Class 2. For example, this class should be considered when one of the following conditions applies: • The main part of the load is supplied via converters; • Welding machines are used; • Large motors are started frequently; • Loads vary quickly Note: IEC61800-2-4 establish individual harmonic voltage distortion 10% ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-3-12 Current emission limits for balanced three-phase equipment < 76A Admissible individual harmonic current In/I1 (%) Admissible harmonic current distortion factors % Minimal Rsce I5 I7 I11 I13 THD PWHD 33 10.7 7.2 3.1 2 13 22 66 14 9 5 3 16 25 120 19 12 7 4 22 28 250 31 20 12 7 37 38 350 40 25 15 10 48 46 ELECTROMAGNETIC COMPATIBILITY (EMC) | IEE519 - 1992 Individual and total voltage distortion limits at PCC (THDv) Isc/IL Permissible values for each individual harmonic voltage Individual and total current distortion limits at PCC (THDi): Harmonic Order Typical Users Special customers with special agreements Isc/IL <11 11≤h<17 17≤h<23 23≤h<35 35≤h THDi <20* 4.0 2.0 1.0 0.6 0.3 5.0 10 2.5 – 3 % 20 2.0 – 2.5 % 1 – 2 large loads 20<50 7.0 3.5 2.5 1.0 0.5 8.0 50 1.0 – 1.5 % A few high-output loads 50<100 10.0 4.5 4.0 1.5 0.7 12.0 100 0.5 – 1 % 100<1000 12.0 5.5 5.0 2.0 1.0 15.0 1000 0.05 – 0.1 % >1000 15.0 7.0 6.0 2.5 1.4 20.0 THD (voltage) 5 – 20 medium-output loads A large number of low-output loads Special applications General system Dedicated system 3% 5% 10% Isc: Maximum short circuit current @ PCC IL : Maximum current consumption by the load @ PCC SD700 FREEMAQ FR SD700 FREEMAQ FL SD700 FREEMAQ FA SD700 KOMPAKT SD700 ¿WHAT SHOULD I DO? The selection of the appropriate technology shall be based in the following items: Is it a new or retrofit project? How many and which is the individual power rating of the harmonics sources? What are the requirements for reactive energy compensation (cos )? Is there any presence of tripleN harmonics (3, 9, 15,…)? HARMONICS MITIGATION TECHNOLOGIES DC CHOKES CHOKES 3% MULTIPULSE SD500, SD700F1&2 SD700 series SD700 series 12,18,24p THDi <35% THDi <15% THDi ≈ 40% L1 L2 L3 L1 L2 NOTCH FILTER SD700 FREEMAQ FL THDi <5% AFE SD700 FREEMAQ FR THDi <4% LH TECHNOLOGIES | SD700 MULTIPULSE DRIVE PE offers 12, 18, 24 pulses drives The rectifiers are shifted 30º / 15º / 7,5º The current harmonics generated are: n = kp ± 1, Where: k = 1, 2, 3, 4, 5... p = number of pulses 12 pulses; 18 pulses; 24 pulses; 11, 13, 23, 25, 35, 37, 47, 49, … 17, 19, 35, 37, 53, 55, …. 23, 25, 47, 49,… 6p THDi ≈ 35% 12p THDi ≈ 15% 18p THDi ≈ 9% 24p THDi ≈ 5% Consider that... THDi in the low voltage side of the transformer will remain being 35% (same as 6pulse drive) LH TECHNOLOGIES | PASSIVE TUNNED FILTERING Zg L1 L2 C1 C2 1st 5th 7th Grid Impedance (Zg) Variation f5th f7th Tunned Filters designed for 5th or 7th Harmonic cancellation with a fixed Grid Impedance ( Zg) Variation on Zg → Increase THDi Variation on Zg → May cause Resonance Valid for original facilities, retrofit projects modify the conditions. 1st 5th 7th LH TECHNOLOGIES | SD700FL NOTCH FILTER L1 L2 Zg L3 C1 SD700FL 1st 5th 7th THDi < 5%, below the limits defined in IEEE519 for all ISC/IL. LCL Notch Filters designed for General Harmonic attenuation and independent from the Grid Impedance ( Zg) Variation on Zg → Do NOT affect to THDi . ZL1>> Zg Built in with robust electric components Never cause resonance LH TECHNOLOGIES | SD700FR ACTIVE FRONT END L1 L2 Zg C1 SD700FR THDi < 5%, below the limits defined in IEEE519 for all ISC/IL. Cos Φ = 1.0 adjustable at any load condition. Energy Regeneration for energy savings and built in Energy registers Invariable Motor voltage against input voltage drops due an adjustable DC Voltage Less Power Wiring and significant space savings No additional installation cost LH TECHNOLOGIES | SD700FA ACTIVE HARMONIC FILTER SD700FA Múltiple 6 pulse drives and other distortion sources Works as a current source monitoring the load current or the line current at the point of interconnection, and injects the inverse current wave that cancels the harmonic distortion THDi control at any load: Selective harmonic cancellation or full spectrum harmonic cancellation at any load conditions Cos Φ = 1.0: It allows the dynamic control of the displacement power factor. Competitive solution and small footprint for retrofits projects. Centralization of the harmonics cancellation leads to a more cost-competitive solution SD700FA ACTIVE HARMONIC FILTER | CONNECTION An open loop configuration measures the load current and injects the inverse current harmonic wave form that cancels the harmonic distortion A closed loop configuration measures the line current at the point of interconnection and injects inverse current harmonic to reach the target established by the user. SD700FA ACTIVE HARMONIC FILTER | SELECTIVE ALGORITHM = + By setting the selective harmonic cancellation you will be able to compensate in perfect opposite phase up to 6 individual harmonics simultaneously up to 25th harmonic (Depending on the switching frequency). The user can individual set the final content of each individual harmonic in %. H5 H7 H11 H13 H17 … 10% 10% 4.5% 4.5% 4% … SD700FA ACTIVE HARMONIC FILTER | FSC ALGORITHMS + By setting the full spectrum harmonic cancellation the unit will not be focused on a specific harmonic number. Any harmonic content will be cancelled by injecting an opposite phase current wave form that results from subtracting the fundamental (50Hz) current wave. = SD700FA ACTIVE HARMONIC FILTER | ZERO-SEQUENCE HARMONICS Zero-sequence harmonics or tripleN are the odd number of the multiple of three harmonics (3,9,15,…) caused by single phase loads (single-phase welders, low consumption lighting, computers, etc..) TripleN harmonics circulate in phase in all three phases. Since the current in the neutral is equal to the sum of the currents in the phases, the neutral current is In= 3·I3 SD700FA has no neutral connection and does not filter zero-sequence harmonics. So alternative filtering techniques can be used (Star-delta transfomer, Zig-Zag inductor, 4Wires filter). SD700FA ACTIVE HARMONIC FILTER | SELECTION SD700FA is a 3 wire Active Harmonic Filter (AHF) ranging from 100A to 630A. The current rating is expressed in RMS current value. The RMS value of a given harmonic spectrum is obtained by the following formula: 𝐼𝑅𝑀𝑆 = 𝐻5 2 + 𝐻7 2 + 𝐻11 2 + 𝐻13 2 + ⋯ + 𝐻49 2 For example: H1 = 300Arms H5 = 60% =180Arms H7 =43% =129Arms 𝐼𝑅𝑀𝑆 = H11 =25% H13 =17% =75Arms =51Arms 1802 + 1292 + 752 + 512 = 239𝐴𝑅𝑀𝑆 SD700FA ACTIVE HARMONIC FILTER | SELECTION SD700FA can perform at the same time the reactive power compensation by injecting leading or lagging current. Compared to traditional capacitor banks, the reactive compensation of the SD700FA is continuous (“stepless”), fast and smooth (no transients at switching). The reactive current required is added to the harmonics rms current. The new ARMS rating is calculated as follows. For example: P = 800kW Ul = 400V DPF = cos φ = 0.90 DPF’ = cos φ’ = 0.95 IARMS_HARM=239A rms 𝑄𝐹 = 𝑃 · tan 𝜑 − tan 𝜑 ′ = 124𝑘𝑉𝐴𝑟 𝐼𝑅𝐸𝐴𝐶𝑇 = 𝑄 3·𝑈 𝐼𝐻𝐴𝑅𝑀 +𝑅𝐸𝐴𝐶𝑇 = 𝐼𝐻𝐴𝑅𝑀 +𝑅𝐸𝐴𝐶𝑇 = = 124𝑘𝑉𝐴𝑟 3 · 400 = 179 𝐴𝑟𝑚𝑠 𝐼𝐻𝐴𝑅𝑀𝑂𝑁𝐼𝐶𝑆 2 + 𝐼𝑅𝐸𝐴𝐶𝑇𝐼𝑉𝐸 2 1792 + 2392 = 298 𝐴𝑟𝑚𝑠 SD700FA ACTIVE HARMONIC FILTER | OPERATION MODES The PRIORITY determines the SD700FA’s current distribution within the available functions: HARMONICS: The SD700FA injects harmonic current up to the pre-set values (%Hi or %Iarms). Once is reached, the remaining capacity can be used by the next priority. PRIORITY HRH HHR HR 1st Harmonics Harmonics Harmonics 2nd Reactive Max. Harmonics Reactive 3rd Max. Harmonics Reactive REACTIVE: The SD700FA injects reactive current trying to reach the pre-set cos φ. As before, the remaining capacity can be used by the next priority. MAX.HARMONICS: If the HARMONICS levels are met, and there is some current capacity left. The SD700FA can continue injecting harmonic current in order to fully cancel the harmonics. Pre-set harmonic value POWER ELECTRONICS appreciate your attention More info: www.power-electronics.com