Three-phase loads: n = (k·6 ± 1): 5, 7, 11, 13, 21, …. Variable speed drives, rectifiers, Electrical arc- furnaces lifts, … Do not appears tripleN harmonics. 3 wires AHF cancellate harmonics HARMONICS CAUSES 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...
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 HARMONICS EFFECTS Voltage RMS Current Apparent Power S= V ·I
USEFUL FORMULAE Displacement Power Factor (cos ) Total Harmonic current Distortion THDi (%) Power factor (PF) Apparent power
USEFUL FORMULAE Utility transformer S (kVA), Zout (%), Vout (V) Linear Loads P (kW), Cos φ Main Feeder L (m), Wire size (mm 2 ), Material (Cu or Al), Conductors (#) Non- Linear Loads P (kW), H (%), cos φ User transformer S (kVA), Zout (%), Vout (V) Distribution Feeders L (m), Wire size (mm 2 ), Material (Cu or Al), Conductors (#) PCC IPC1 IPC2 IPC3 PCC IPC1 IPC2 IPC3 Zsc Zt Zf’ Zf2’ Zf2’’Zf2’’’ Zf3’ Zf4’’ Zf4’ Zf4’’’ THDi levels evolution THDu levels evolution Private Grid Public Grid PCC: Point of common coupling IPC Internal point of coupling
EMC Electromagnetic Compatibility Low frequency F <150 kHz THD Flicker EMI Electromagnetic Interference EMS Electromagnetic Susceptibility Medium Frecuency 150 kHz< f < 30MHz Conduced High Frecuency f > 30MHz Radiated Radio Frequency Conduced Radiated Surges Electrical fast transients Electrostatic discharges THD Voltage dips and interruptions IEC61800-3 ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION
ELECTROMAGNETIC COMPATIBILITY (EMC) | STANDARDS CE marking for variable speed drive requires compliance with directive EMC 2004/108/CE EMC 2004/108/CE EMC 2004/108/CE requires compliance with standard IEC61800-3 IEC61800-3 IEC61800-3 states that the manufacturer shall provide the current harmonic level under certain conditions. IEC61000-2-2 IEC61000-2-4 IEC61000-3-4 IEC61000-3-12 IEEE519 - 1992 ¿Compatibility levels? IEC61000-2-2: Public Low Voltage Power Supply Systems IEC61000-2-4: Industrial and non- public networks. Individual VHD and THDv (%) depending on the 3 environmetal class defined Public networks up to 600V THD and PWHD up to: IEC61000-3-4 <16A IEC61000-3-12 < 75A THDv THDi Recomended practives and requirements for harmonic control in Electrical Power Systems. Individual VHD and THDv (%) depending on Isc/I L Individual CHD and THDI (%) depending on Isc/I L
ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-2-4 CLASSDESCRIPTIONTHDv (%) CLASS 1Location 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% CLASS 2 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% CLASS 3 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 10% Note: IEC61800-2-4 establish individual harmonic voltage distortion
ELECTROMAGNETIC COMPATIBILITY (EMC) | IEE519 - 1992 Harmonic Order Isc/IL <11 11≤h<1717≤h<2323≤h<3535≤hTHDi <20* 4.02.01.00.60.35.0 20<50 7.03.52.51.00.58.0 50<100 10.04.54.01.50.712.0 100<1000 12.05.55.02.01.015.0 >1000 15.07.06.02.51.420.0 Isc: Maximum short circuit current @ PCC I L : Maximum current consumption by the load @ PCC Individual and total current distortion limits at PCC (THDi): Isc/IL Permissible values for each individual harmonic voltage Typical Users 10 2.5 – 3 % Special customers with special agreements 20 2.0 – 2.5 %1 – 2 large loads 50 1.0 – 1.5 %A few high-output loads 100 0.5 – 1 %5 – 20 medium-output loads 1000 0.05 – 0.1 %A large number of low-output loads Individual and total voltage distortion limits at PCC (THDv) Special applications General system Dedicated system THD (voltage) 3%5%10%
¿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,…)?
LH TECHNOLOGIES | SD700 MULTIPULSE DRIVE n = kp ± 1, Where: k = 1, 2, 3, 4, 5... p = number of pulses PE offers 12, 18, 24 pulses drives The rectifiers are shifted 30º / 15º / 7,5º The current harmonics generated are: 6p THDi ≈ 35% 12p THDi ≈ 15% 18p THDi ≈ 9% 24p THDi ≈ 5% 12 pulses; 11, 13, 23, 25, 35, 37, 47, 49, … 18 pulses; 17, 19, 35, 37, 53, 55, …. 24 pulses; 23, 25, 47, 49,… 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 C1 Tunned Filters designed for 5 th or 7 th 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. f 5th f 7th 1 st 5 th 7 th 1 st 5 th 7 th Grid Impedance (Zg) Variation L2 C2
LH TECHNOLOGIES | SD700FL NOTCH FILTER Zg L1 C1 L2 L3 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. Z L1 >> Zg Built in with robust electric components Never cause resonance 1 st 5 th 7 th SD700FL
LH TECHNOLOGIES | SD700FR ACTIVE FRONT END Zg L1 C1 L2 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 SD700FR
LH TECHNOLOGIES | SD700FA ACTIVE HARMONIC FILTER 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
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 25 th harmonic (Depending on the switching frequency). H5H7H11H13H17… 10% 4.5% 4%… IEEE519 The user can individual set the final content of each individual harmonic in %. + =
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..) 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). 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·I 3
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: For example: H 1 = 300Arms H 5 = 60%=180Arms H 7 =43%=129Arms H 11 =25%=75Arms H 13 =17%=51Arms
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 A RMS rating is calculated as follows. For example: P = 800kW Ul = 400V DPF = cos φ = 0.90 DPF’ = cos φ’ = 0.95 I ARMS_HARM =239A rms SD700FA ACTIVE HARMONIC FILTER | SELECTION
SD700FA ACTIVE HARMONIC FILTER | OPERATION MODES PRIORITYHRHHHRHR 1stHarmonics 2ndReactiveMax. HarmonicsReactive 3rdMax. HarmonicsReactive The PRIORITY determines the SD700FA’s current distribution within the available functions: Pre-set harmonic value 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. 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.
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