LOW HARMONICS SOLUTIONSFREEMAQ SERIES

February 2014

1 Harmonic Causes

2 Harmonic Effects

3 Useful Formulae

4 EMC – THD Standards

5 PE Low Harmonics Techn.

6 SD700FA AHF

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

VoltageRMS CurrentApparent Power S= V ·I

USEFUL FORMULAE

𝑃𝐹= 1ξ1+ 𝑇𝐻𝐷𝐼2 · 𝑐𝑜𝑠 𝜑 = 𝐼50𝐻𝑧𝐼𝑟𝑚𝑠 · 𝑐𝑜𝑠 𝜑

Displacement Power Factor (cos )

Total Harmonic current Distortion THDi (%)

Power factor (PF)

𝑇𝐻𝐷= ඨσ 𝐼𝑛2𝑛=∞𝑛=2𝐼1

𝑆𝑇 = ඥ𝑃2 + 𝑄2 + 𝐷2

Apparent power

𝐷𝑃𝐹= 𝑐𝑜𝑠 𝜑 = 𝑃 (𝑘𝑊)𝑆 (𝑘𝑉𝐴)

USEFUL FORMULAE

Utility transformerS (kVA), Zout (%), Vout (V)

Linear LoadsP (kW), Cos φ

Main FeederL (m), Wire size (mm2), Material (Cu or Al), Conductors (#)

Non- Linear LoadsP (kW), H (%), cos φ

User transformerS (kVA), Zout (%), Vout (V)

Distribution FeedersL (m), Wire size (mm2), Material (Cu or Al), Conductors (#)

PCC

IPC1

IPC2

IPC3

PCC

IPC1

IPC2

IPC3

Zsc

Zt

Zf’

Zf2’ Zf2’’ Zf2’’’

Zf3’

Zf4’’Zf4’ Zf4’’’

TH

Di l

evel

s ev

olut

ion

TH

Du

leve

ls e

volu

tion

Private Grid

Public Grid

PCC: Point of common couplingIPC Internal point of coupling

ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION

EMCElectromagnetic Compatibility

EMIElectromagnetic Interference

EMSElectromagnetic Susceptibility

Maximum Emission level

Minimum Immunity level

Device Immunity level

Device emission level

COMPATIBILITY MARGIN

EN

VIR

ON

ME

NT

CL

AS

S

Frequency spectrum

Am

plit

ud

e

EMCElectromagnetic Compatibility

Low frequency

F <150 kHz

THD Flicker

EMIElectromagnetic Interference

EMSElectromagnetic Susceptibility

MediumFrecuency

150 kHz< f < 30MHz

Conduced

HighFrecuency

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.

IEC61000-2-2IEC61000-2-4

IEC61000-3-4IEC61000-3-12

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/IL

Individual CHD and THDI (%) depending on Isc/IL

ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-2-4

CLASS DESCRIPTION THDv (%)CLASS 1 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%

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) | IEC61800-3-12

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

Current emission limits for balanced three-phase equipment < 76A

ELECTROMAGNETIC COMPATIBILITY (EMC) | IEE519 - 1992

Harmonic Order

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

20<50 7.0 3.5 2.5 1.0 0.5 8.0

50<100 10.0 4.5 4.0 1.5 0.7 12.0

100<1000 12.0 5.5 5.0 2.0 1.0 15.0

>1000 15.0 7.0 6.0 2.5 1.4 20.0

Isc: Maximum short circuit current @ PCCIL : Maximum current consumption by the load @ PCC

Individual and total current distortion limits at PCC (THDi):

Isc/ILPermissible 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%

SD700 FREEMAQ FR SD700 FREEMAQ FL

SD700 KOMPAKT

SD700

SD700 FREEMAQ FA

¿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,…)?

DC CHOKESSD500, SD700F1&2

THDi ≈ 40%

CHOKES 3%SD700 series

THDi <35%

L1

L2

L3 L1

L2

HARMONICS MITIGATION TECHNOLOGIES

MULTIPULSESD700 series 12,18,24p

THDi <15%

NOTCH FILTERSD700 FREEMAQ FL

THDi <5%

AFESD700 FREEMAQ FR

THDi <4%

VSD VSD

= 0 º

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 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.

f5th f7th

1st 5th 7th

1st 5th 7th

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 . ZL1>> Zg

Built in with robust electric components

Never cause resonance

1st 5th 7th

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 25th harmonic (Depending on the switching frequency).

H5 H7 H11 H13 H17 …

10% 10% 4.5% 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·I3

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 = ට𝐻52 + 𝐻72 + 𝐻112 + 𝐻132 + ⋯+ 𝐻492

For example:H1 = 300ArmsH5 = 60% =180ArmsH7 =43% =129Arms

H11 =25% =75ArmsH13 =17% =51Arms

𝐼𝑅𝑀𝑆 = ඥ1802 + 1292 + 752 + 512 = 239𝐴𝑅𝑀𝑆

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 = 800kWUl = 400V DPF = cos φ = 0.90DPF’ = cos φ’ = 0.95 IARMS_HARM=239A rms 𝐼𝐻𝐴𝑅𝑀+𝑅𝐸𝐴𝐶𝑇 = ට𝐼𝐻𝐴𝑅𝑀𝑂𝑁𝐼𝐶𝑆2 + 𝐼𝑅𝐸𝐴𝐶𝑇𝐼𝑉𝐸2

𝑄𝐹 = 𝑃·ሺtan𝜑− tan𝜑′ሻ= 124𝑘𝑉𝐴𝑟

𝐼𝑅𝐸𝐴𝐶𝑇 = 𝑄ξ3· 𝑈= 124𝑘𝑉𝐴𝑟ξ3 · 400 = 179 𝐴𝑟𝑚𝑠

SD700FA ACTIVE HARMONIC FILTER | SELECTION

𝐼𝐻𝐴𝑅𝑀+𝑅𝐸𝐴𝐶𝑇 = ඥ1792 + 2392 = 298 𝐴𝑟𝑚𝑠

SD700FA ACTIVE HARMONIC FILTER | OPERATION MODES

PRIORITY HRH HHR HR

1st Harmonics Harmonics Harmonics

2nd Reactive Max. Harmonics Reactive

3rd Max. Harmonics Reactive

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.

POWER ELECTRONICSappreciate your attention

More info:

www.power-electronics.com

More info:

www.power-electronics.com