power quality and harmonic mitigation

8/2/2019 Power Quality and Harmonic Mitigation

http://slidepdf.com/reader/full/power-quality-and-harmonic-mitigation 1/62

Make the most of your

energy

Make the most of

your energySM

Add photo in this area

WWW Seminar

November 10, 2009

Power Quality andHarmonic Mitigation

WWW Seminar



Schneider Electric 2-Power Quality Correction Group – October 2009

Agenda

● Overview

● Harmonic Basics

● IEEE 519

● Conventional Harmonic Mitigation Methods

●

AccuSine®

PCS● Applications & Installation Notes

● Specification Recommendations

● Summary




Schneider Power Quality Correction Group

●Power Factor Correction and

Harmonic Filtering:●

Capacitor Systems

●LV & MV up to 15 kV

●

Fixed, Standard and

Detuned Auto Banks●

AccuSine PCS

●Voltage Regulation:

●

Hybrid VAR Compensator

●

Electronic Sag Fighter


http://slidepdf.com/reader/full/power-quality-and-harmonic-mitigation 4/62Schneider Electric 4-Power Quality Correction Group – October 2009

Fundamental

3rdHarmonic

Harmonic Basics

● What are harmonics?

●

Proliferated by power semiconductor devices

●Converts power (AC to DC)

●

A harmonic is a component of a periodic wave

having a frequency that is an integer multiple of

the fundamental power line frequency

●

Characteristic harmonics are the

predominate harmonics seen by the power

distribution system

●

Predicted by the following equation:

●

Hc = np +/- 1●hC

= characteristic harmonics to be expected

●n = an integer from 1,2,3,4,5, etc.

●p = number of pulses or rectifiers in circuit

Harmonic Frequency Sequence1 60Hz +

2 120Hz 0

3 180Hz 04 240Hz 0

5 300Hz -6 360Hz 0

7 420Hz +: : :

19 1140Hz +

5thHarmonic

7thHarmonic

ResultantWaveform



Multi-pulse ConvertersHn

1 phase

4-pulse

2 phase

4-pulse

3 phase

6-pulse

3 phase

12-pulse

3 phase

18-puls

3 x x

5 x x x

7 x x x

9 x x

11 x x x x

13 x x x x

15 x x

17 x x x x

19 x x x x

21 x x

23 x x x x

25 x x x x

27 x x

29 x x x

31 x x x

33 x x

35 x x x x x

37 x x x x x

39 x x

41 x x x

43 x x x

45 x x

47 x x x x

49 x x x x

Harmonics present by rectifier design

Type of rectifier

Hc

= np +/- 1

Hc

= characteristic

harmonic order present

n = an integer

p = number of pulses



Harmonic Basics●Nonlinear loads draw it

●Example: 6-Pulse VFD

Inver ter Conver ter

DC bus

M

ABC




Harmonic Basics

● Why a concern?●

Current distortion

●Added heating, reduced capacity in :

–

Transformers

–

Conductors and cables

●

Heating effect proportional to harmonic order

squared

●

Nuisance tripping of electronic circuit

breakers (thermal overload)

●Blown fuses

●Detrimental to generators

– Heating of windings●Detrimental to UPS

–

UPS can’t supply the current

Loads

Ih

Vh

= Ih

x Zh




Harmonic Basics

●Voltage distortion●

Interference with other electronic loads

●Faulting to destruction

●

Creates harmonic currents in linear loads

●

Generator regulators can’t function

●Shut downs

●Not compatible with standard PF caps●

Potential resonance condition

●Excessive voltage●

Overheating of PF correction capacitors

●

Tripping of PF protection equipment

●

Shutdown / damage to electronic equipment

Loads

Ih

Vh

= Ih

x Zh




Total Power Factor

TPF

= (DPF)

x (Distortion factor)

DPF =KW

KVAf = Cos

Distortion Factor =1

1 + THD(I)2

TPF = Total or true power factor DPF = Displacement power factor

Distortion Factor = Harmonic power factor

= Cos




Total Power Factor Example

●Variable frequency drive (PWM type)

●

DPF = .95

●

THD(I) = 90%

●(no DC choke & no input line reactor)

●

Distortion Factor =

●TPF = .95 x .7433 = .7061

11 + .92

= .7433




How are harmonics handled today?

●Mixed bag of objectives

●Basis of compliance is mixed

–

THDi, THDv, TDD?

–

IEEE 519-1992?

●Where is PCC?

●What level of harmonics is to be attained?

●How to obtain compliance?

–

Sometimes defined

–

Sometimes open ended

●

Validation

●Poorly defined

●By each equipment vendor

●No ‘Total Responsibility’

for harmonics

●

Has the User been protected where it matters – inside the facility




Typical Present Situation

●Specifications direct manufacturers of nonlinear loads to comply withinequipment specifications

●Manufacturers of nonlinear loads have other concerns

●

Sell standard equipment at competitive prices

●Leads to minimized harmonic solutions●Leads to misleading information about harmonic performance

●Leads to operational difficulties

–

e.g. Can’t operate on backup generators/UPS

●

Force the IEEE 519 discussion to the utility PCC

●Many types of solutions are not compatible

●

Each manufacturer does his own thing without regard to other solutions

●

Approaches are for ‘my’

equipment only

●

‘My’

simulation is for ‘my’

equipment only –

I can’t include the others

● ‘Total’

solution not achieved

●

User has system that exceeds specification objectives

●

Consulting engineers can’t get overall compliance




ANSI Standard IEEE 519-1992

● Issues addressed:

●

THD(V) delivered by utility to user (Chapter 11)

●THD(V) must be < 5% [< 69 KV systems]

●

Defines the amount of TDD a user can cause (Chapter 10)

●Based upon size of user in relation to power source

●Table 10.3 for systems < 69 kV

●

Defines limits for voltage notches caused by SCR rectifiers – Table10.2

●

Defines PCC (point of common coupling)




IEEE 519-1992

●Defines current distortion as TDD

●

Total Demand Distortion

●

Largest amplitude of harmonic current occurs at maximum

load of nonlinear device –

if electrical system can handle

this it can handle all lower amplitudes

●Always referenced to full load current

●Effective meaning of current distortion

●Defines voltage distortion as THD●

Total harmonic voltage distortion

●Does not use THD(I)

●

Total harmonic current distortion

●

Instrument measurement (instantaneous values)

●

Uses measured load current to calculate THD(I)




IEEE 519-1992

Total I,

rms

Fund I,

rms

Harm I,

rms THD(I) TDD

Full load 936.68 936.00 35.57 3.8% 3.8%

836.70 836.00 34.28 4.1% 3.7%

767.68 767.00 32.21 4.2% 3.4%592.63 592.00 27.23 4.6% 2.9%

424.53 424.00 21.20 5.0% 2.3%

246.58 246.00 16.97 6.9% 1.8%

111.80 111.00 13.32 12.0% 1.4%

Measured

• TDD and THD(I) are not the same except at 100% load

• As load decreases, TDD decreases while THD(I) increases.

• Example:




IEEE 519-1992 Table 10.3

Current Distortion Limits for General DistributionSystems (<69 kV)

Isc / Iload <11 11<=h<17 17<=h<23 23<=h<35 h>=35 TDD<20 4.0% 2.0% 1.5% 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% 0.2% 1.0% 15.0%

>1000 15.0% 7.0% 6.0% 2.5% 1.4% 20.0%

Isc = short circuit current capacity of source

Iload = demand load current (fundamental)

(TDD = Total harmonic current distortion measured against

fundamental current at demand load.)

TDD = Total Demand Distortion




Harmonic Standards

•

Most harmonic problems are not at the PCC with utility.

Typically harmonic problem occur:

• Within a facility• With generator & UPS operation

• Where nonlinear loads are concentrated

•

Need to protect the user from self by moving the harmonic

mitigation requirements to where harmonic loads are located




Agenda

I. Harmonic Basics

II. Conventional Harmonic Mitigation MethodsIII. AccuSine® PCS

IV. Applications

V. Specification Recommendations

VI. Summary




Harmonic Mitigation Methods

●Typically applied per device

●

Line reactors/DC bus chokes/isolation transformers

●

5th

harmonic filters (trap filters)

●

Broadband filters

●

Multi-pulse transformers/converters

●

Active front end (AFE) converter

●System solution●

Active harmonic filter

Harmonic mitigation methods (Applied per VFD)



Harmonic mitigation methods - (Applied per VFD)

Solution Advantage Disadvantage

Typical %

TDD

Typical Price

Multiplier*Inc rease shortc ircuit capac ity Reduc es THD(V)

●Inc rea ses TDD●Not likely to oc cur**

Dependentup on SCR***

Cost of transformer andinsta lla tion change out

C-Less Tec hnolog y

●Lower TDD●Simp lified design

●Less c ost

●Comp lianc e is limited●Application limited

●Size limited 30 - 50% TDD 0.90 - 0.95

Imped anc e (3% LRor 3% DC c hoke)

●Low c ost ad de r●Simple ●Comp lianc e d ifficult 30 - 40% TDD 1.05 - 1.15

5th Harmonic filterRed uc es 5th & to ta lTDD

●Does not meet ha rmoniclevels at higher orders^ 18 - 22% TDD 1.20 - 1.45

Broa dband filter Reduc es TDD (thru13th)

●

Large heat losses●Application limited 8 - 15% TDD 1.25 - 1.50

12-pulse rec tifiers●Reduc es TDD●Reliable

●Large footprint/ heavy●Go od for >100 HP 8 - 15 % TDD 1.65 - 1.85


●Large footprint/ heavy●Go od for >100 HP 5 - 8% TDD 1.65 - 1.85

Ac tive front endconverter

●Very go od TDD●Regenerationpossible

●Large footprint/ heavy●Very high c ost per unit●High heat losses < 5% TDD 2.0 - 2.5

* Pric e c ompared to a sta ndard 6-pulse VFD.** Utilities and users are no t likely to c ha nge their distribution systems.*** Inc reasing short c ircuit capac ity (low er imped anc e sourc e o r la rger KVA c apac ity) ra ises TDD but lowers THD(V).^ Ca n be sa id for a ll me thods listed .

Harmonic mitigation methods





Solution Advantage Disadvantage

Typical %

TDD

Typical Price

Multiplier*Inc rease shortc ircuit capac ity Reduc es THD(V)

●Inc rea ses TDD●Not likely to oc cur**

Dependentup on SCR***

Cost of transformer andinsta lla tion change out

C-Less Tec hnolog y

●Lower TDD●Simp lified design

●Less c ost

●Comp lianc e is limited●Application limited

●Size limited 30 - 50% TDD 0.90 - 0.95

Imped anc e (3% LRor 3% DC c hoke)

●Low c ost ad de r●Simple ●Comp lianc e d ifficult 30 - 40% TDD 1.05 - 1.15

5th Harmonic filterRed uc es 5th & to ta lTDD

●Does not meet ha rmoniclevels at higher orders^ 18 - 22% TDD 1.20 - 1.45

Broa dband filter Reduc es TDD (thru13th)●

Large heat losses●Application limited 8 - 15% TDD


●Large footprint/ heavy●Go od for >100 HP 8 - 15 % TDD 1.65 - 1.85


●Large footprint/ heavy●Go od for >100 HP 5 - 8% TDD 1.65 - 1.85

Ac tive front endconverter

●Very go od TDD●Regenerationpossible

●Large footprint/ heavy●Very high c ost per unit●High heat losses < 5% TDD 2.0 - 2.5

* Pric e c ompared to a sta ndard 6-pulse VFD.** Utilities and users are no t likely to c ha nge their distribution systems.*** Inc reasing short c ircuit capac ity (low er imped anc e sourc e o r la rger KVA c apac ity) ra ises TDD but lowers THD(V).^ Ca n be sa id for a ll me thods listed .

AccuSine

AccuSine




Inductors/Transformers/DC Bus Chokes

Description:Converter-applied inductors or isolation transformers.

●Pros:

●

Inexpensive & reliable●

Transient protection for loads

●

1st Z yields big TDD reduction (90% to 35% w/3% Z)

●

Complimentary to active harmonic control

●Cons:●

Limited reduction of TDD at equipment terminals after 1st Z

●

Reduction dependent on source Z




5th Harmonic Filter (Trap Filter)

•

Inductor (Lp

) and Capacitor (C) provide low

impedance source for a single frequency

(5th)

• Must add more tuned filters to filter morefrequencies

•

Inductor Ls

required to detune filter from

electrical system and other filters

•

If Ls

not present, filter is sink for all 5th

harmonics in system

•

If Ls

not present, resonance with other

tuned filters possible

•

Injects leading reactive current (KVAR) at

all times –

may not need

LoadVs

Zs

Lp

C

Ls




• Mitigates up to 13th

order or higher

• Each inductor (L) > 8% impedance

• V drops ~ 16% at load

• Trapezoidal voltage to load

•Can only be used on diode converters

• Prevents fast current changes (only good for centrifugal loads)

• When generators are present, re-tuning may be required

• Capacitor (C) designed to boost V at load to proper level (injects leading VARs)

• Physically large• High heat losses (>5%)

• Series device

Broadband Filters

Load

Source

L L

C

~Lp




Multi-Pulse Drives

Description: Drives/UPS with two (12 pulse) or three (18 pulse) input bridges

fed by a transformer with two or three phase shifted output windings.

●Pros:

●

Reduces TDD to 10% (12 pulse) & 5% (18 pulse) at loads

●

Reliable

●Cons:

●

High installation cost with external transformer

●

Large footprint (even w/autotransformer)

●

Series solution with reduction in efficiency

●

One required for each product

●

Cannot retrofit





Harmonic mitigation methodsVFD mitigation topologies

6-Pulse converter

“C-less” or 3% reactance min (ifincluded); small footprint,

simplified cabling

Current waveform distortedTDD 30% to 40% with 3% reactor(depending on network impedance)

Externally mounted 3 winding

transformer; more wire andcabling; complicated

Current slightly distortedTDD 8% to 15% (depending onnetwork impedance)

12-Pulse converter 18-Pulse converter

Large footprint, more steel& copper (losses)

Current wave form goodTDD 5% to 7% (depending onnetwork impedance)

0

100

A

6 pulse

0

100

A

12 pulse

0.0s 0.02s

0

100

A

18 pulse

+

-

DC Bus Load

Delta

Delta

Wye

AC Line

A

B

C

DC+

DC-

LineReactor

Rectifier Assembly

TransformerTertiary

MultipulseTransformer

A

BC

1

2

3

4

56

7

8

9

DC LinkReactor

M

A ti F t E d (AFE) C t




Active Front End (AFE) Converters

●Used in UPS and VFD●Replaces diode converter with IGBT converter

●The hype

●

Permits current smoothing on AC lines (< 5% TDD)●

Permits 4-quadrant operation of VFD

●

Maintains unity TOTAL PF

●

Meets all harmonics specs around the world

A

C

S

o

u

r

c

eFilter

Converter Inverter

DC Bus

AC

Motor

IGBT IGBT

VFD

Input Filter

Required to

limit THDv

to

<5%

AFE C




AFE Converters

Significant harmonics above 50th

order

American Bureau

of Shipping (ABS)

requiresexamination to

100th

order when

AFE applied

Higher frequencies

yield higher heating

of current path &

potential resonance

with capacitors




AFE Converters●

Cons●

Larger and more expensive than 6 pulse drives

●Approximately twice the size & price

●

Mains voltage must be free of imbalance and voltag

harmonics●Generates more harmonics

●

Without mains filter THD(V) can reach 40%

●

Requires short circuit ratio >

40 at PCC

●

Switched mode power supplies prohibited●

Capacitors prohibited on mains

●

IGBT & SCR rectifiers prohibited on same mains

●No other nonlinear loads permitted

200

KVA

rated

PWM

VFD

DCDrive

PFcaps

100

KVA

rated

AFE

VFD




Agenda

I. Harmonic Basics

II. Conventional Harmonic Mitigation Methods

III. AccuSine® PCSIV. Applications

V. Specification RecommendationsVI. Summary

The System Solution




The System Solution

●The System Solution:

●

Single point of responsibility for the ‘total’

harmonics

●

One specification for harmonic definitions

●

One validation responsibility and guarantee

● Standard nonlinear products

●

3% input line reactors on most non-linear devices, 3% DC bus choke okay for

PWM VFD

● Limits rms

current at load for diode rectifiers

● Avoids interaction with snubber

circuit for SCR rectifier

●

Best cost and performance

● Compatible with all nonlinear products

●

Compliance with harmonic specifications

●

Controls harmonic levels with facility

S h id El t i ’ S l ti




Schneider Electric’s Solution

● AccuSine Power Correction System (PCS)

●

Active harmonic filter

● Provides 5% TDD per load or system

● Cancels everything from 2nd

to 50th

harmonic order

● Used on any/all nonlinear load

●

Active reactive current correction● Does not use PF capacitors

● Used to correct Displacement PF

● In conjunction with or independent of harmonic control (dual mode)

● High-speed reactive power

Active Harmonic Filter System Solution




Active Harmonic Filter System Solution

● Applied to one or many nonlinear loads●

VFD, UPS, UV, DC drives, DC power supplies

● Provides DPF correction

● More cost effective for multiple loads●

For two or more drives, AccuSine and 6 pulse drive combination

has lower initial and operating costs than 18 pulse drives

●

For installations with redundant drives, size AccuSine for the

operating drives only

● Saves space● Lower heat losses

● Not critical to operation●

Parallel connected

Comparison of 18-P VFD to




Co pa so o 8 to

AccuSine PCS + standard VFD

●Footprint required

●

AccuSine PCS+ Std VFD less than 18-P VFD

(w/autotransformer) for all conditions

●Heat losses

●

AccuSine PCS+ Std VFD less than 18-P VFD

●Exception at single units of 50-75 HP, advantage 18-P VFD

●

Less costly to operate AccuSine PCS+ Std VFD●

Less site cooling required with AccuSine PCS + Std VFD

●Price (first cost)

●

When more than one VFD, AccuSine PCS + Std VFD always

beats 18-P VFD

●

If only one VFD involved, 300-500 HP sizes favor 18-P VFD

A Si A ti H i Filt




AccuSine Active Harmonic Filter

AHFLoad

L

CT

Source

Is

Ia

I l

~

AHF

•Parallel connected

•Is

+ Ia

= Il

•Ia

includes 2nd

to 25/50th

harmonic current

•Is

<5% TDD

AccuSine® PCS




AccuSine® PCS

Power Diagram

+

C

E

C

E

C

E

C

E

C

E

C

E

C

LineInductor

Filter

Board

Pre-charge

Contactor

Inductor

Fuse

Fuse

Fuse

AC

Lines

S4

S5

S6

S1

S2

S3DC Bus

Capacitors

IGBT Module

System Solution




System Solution

AccuSine®

PCS Sizing Example

●

A 125 HP variable torque 6-pulse VFD with 3% LR

●

Required AHF filtering capability = 47.5 amperes

●

Two 125 HP VT 6-pulse VFD w/3% LR●

Required AHF size = 84.4 amps

●

Three 125 HP VT 6-pulse VFD w/3% LR

●


●

Six 125 HP VT VFD w/3% LR●


●

(not 6 x 47.5 = 285 amps)

AS off AS onOrder % I fund % I fund

AccuSine Performance




Fund

100.000%100.000%

3

0.038% 0.478%

5

31.660% 0.674%

7

11.480% 0.679%

9

0.435%

0.297%

11

7.068%

0.710%

13

4.267%

0.521%

15

0.367%

0.052%

17

3.438%

0.464%

19

2.904%

0.639%

21

0.284%

0.263%

23

2.042%

0.409%

25

2.177%

0.489%

27

0.293%

0.170%29

1.238%

0.397%

31

1.740%

0.243%

33

0.261%

0.325%

35

0.800%

0.279%

37

1.420%

0.815%

39

0.282%

0.240%

41

0.588%

0.120%

43

1.281%

0.337%

45

0.259%

0.347%

47

0.427%

0.769%

49

1.348%

0.590%TDD 35.28% 2.67%

AccuSine Performance

AccuSine injection

Source current

At VFD Terminals

700 HP Drive – AccuSine ON – OFF




Applications




Applications

● Most common –

VFD sites

●

Centrifugal pumps and fans

●Pumping Stations

– Potable –

Wastewater

●Wastewater Plants

●Water Purification (potable)

● Disinfectant Systems

●UV systems (ultraviolet)

–

Electronic ballasts –

3

●

Ozone generators (SCR power supplies)● Industrial –

in-rush support

AccuSine PCS Specifications




p

● Universal Application

●

208 –

480 VAC

● No user action required to set

● Highly customized transformers for higher voltages (to 15 kV)

●

50 or 60 Hz

● Fuse protected (200,000 AIC)

● UL 508 & CSA approved

● CE EMC -

400V

● Logic ride through –

1 to 10 minutes

Specification Discussion




Specification Discussion

●

Write a specification in Section 16 for an active harmonic filter ●

Specify any points of concern for insertion of AHF

●Size of AHF

●Located per electrical bus

●

Specify total responsibility for all harmonics in facility

●

Specify TDD levels desired at each location

●5% TDD guarantees 5% THDv

(caused by the loads) with any source

●

Specify compliance tests for each location

●

Write standard nonlinear load specification

●Reduces harmonic incompatibilities and product interactions

●Need 3% impedance on each nonlinear load

●

Universal solution

●

Good for all nonlinear loads

●

Apply AccuSine per electrical bus (best economics)

●

Can attain 5% TDD per load or bus inside the plant

●

Avoids harmonic problems –

both TDD and THD(V)

●

Write TDD specs not THD(I) at 5%

AccuSine Tools




● Internet Tools●

Active Filter Guide Spec (www.reactivar.com)

● Stand alone spec section (Section 16)

● Includes harmonic and PF correction requirements

●

Selection Program (www.squaredleantools.com)●

Easy selection based upon loads not source (same

selection for utility or generator)

● Simple tool to use

●

We guarantee results if used properly duringdesign/layout stage

●

Brochure

●

Application Notes

● Water/wastewater and other applications

●

Installation Bulletin

● Best/total information for consultant

●

MCC Selector

Product Package




g

●Standard (UL only)●Enclosed –

NEMA 1

●

50 amp –

48”H x 21”W x 19”D, 250 lbs

●

100 amp –

65”H x 21”W x 19”D, 350 lbs

●Wall mounted●

300 amp –

75”H x 32”W x 20”D, 775 lbs

●Free standing

●Chassis & NEMA12 Also Available

Product Package




Product Package

● International enclosures

●

NEMA 12, IP30, IP54

●

50 amp –

75”(1905mm) x 31.5”(800mm)

x 23.62”(600mm)●Weight –

661Ib(300Kg)

●

100 amp –

75”(1905mm) x

31.5”(800mm) x 23.62”(600mm)

●Weight –

771Ib(350 Kg)

●

300 amp –

91”(2300mm) x

39.37”(1000mm) x 31.5”(800mm)

●Weight –

1212Ib(550 Kg)

●

Free standing with door interlocked

disconnect●

CE Certified, C-Tick, ABS, UL, CUL

Product Re-packaging




p g g

●Maximum ambient into air inlet –

400C

●Must meet air flow at inlet of AccuSine

●

50 amp –

300 CFM

●

100 amp – 500 CFM●

300 amp -

1250 CFM

●Heat released

●

50 amp –

1800 watts

●

100 amp –

3000 watts

●

300 amp –

9000 watts

●DIM considerations required

●

On chassis

●

Remote with cable

Product Re-packaging




Product Re packaging

●MCC Packaging

●

50 & 100 amp models only

●

Requires one vertical 20”

x 20”

section

●

Includes circuit breaker

AccuSine PCS Current Transformers




AccuSine PCS Current Transformers

●AC lines●

Class 1

●

400 Hz

●

Four sizes

●500:5/1000:5/3000:5/5000:5●

Stock split core –

round units

●Added to AccuSine (when parallel connected & source sense)

●

Use solid core at equal ratio as AC lines CT

AccuSine PCS Performance





Source XFMR

Load(s)

Is

Ias

•AccuSine Logic

•Is + Ias = Il

•AccuSine injects the harmonics the loads want

DEFINITIONS

Is = source current

Ias = AccuSine current

Il = total load current

(vector representations)

Il






●

Obtain 5% TDD (current distortion)

●

Overall 10:1 attenuation

●Cos

= .998

●

Obtain near unity lagging DPF (Cos

●

Optional: Inject to obtain a user set point

●

Either or both functions

●

VAR compensation

●

100 second

detect-to-inject

●

Dynamic response

●

½ cycle to full control for step load changes

AccuSine PCS Overall Performance




AccuSine PCS Overall Performance

●Harmonic compensation

●

2nd

through 50th

order

●

Includes inter-harmonics

●

Independent of source impedance

●

Selection and operation same whether on AC line or backup generator or UPSoutput

●Reactive current injection

●

Secondary function to harmonic mode

●

Defaults to unity lagging set point

●

Injects leading or lagging reactive current

AccuSine PCS Cos Performance




AccuSine PCS Cos

Performance

● In dual mode (Cos

+ Cos

)

●

Reactive current injection is secondary to harmonic mitigation

●Activation of Cos in the field via DIM

●Default to unity lagging Cos ●

Can enter a set point (i.e. 0.90 lagging)

●

Can inject leading (capacitive) or lagging (inductive) reactive current

Dual Mode Operation




Dual Mode Operation

Ias = rms output current of AccuSine

Ih = rms harmonic current

Ir = rms reactive current

Ias = Ih2 + Ir

2

Ias Ih Ir

100.0 10.0 99.5

100.0 20.0 98.0

100.0 30.0 95.4

100.0 40.0 91.7

100.0 50.0 86.6100.0 60.0 80.0

100.0 70.0 71.4

100.0 80.0 60.0

100.0 90.0 43.6

100.0 95.0 31.2

Examples




AccuSine PCS Installation Considerations (When in ‘harmonic mode’

–

does not apply for ‘reactive mode-only’)

AccuSine PCS Installation Considerations




●

For Optimal Performance:●

Impedance –

3% input line reactors (minimum) on every nonlinear load

●

Transformer, 3% DC bus choke for PWM VFD or long power cables (not

encapsulated type) can substitute for line reactors

● Standardizes selection of AccuSine●Diode rectifiers: Need to limit rms

current at load (limits rise of Ihrms

at load)

●Thyristor rectifiers: Need to protect snubbers (capacitors) on thyristor

●

No capacitors downstream of CT

AccuSine PCS Installation Considerations




This configuration provides individual AccuSineoperation per side regardless of breaker positions.

Main –

Left Main –

Right

CBm

l CBmr

Tie

CTml CTtl CTtr CTmr

AccuSine RAccuSine L

CBal CBar

Main-tie-main

Summary




y

●Universal solution

●

Good for all nonlinear loads (3-phase)

●

Apply AccuSine per electrical bus (best economics)

●System Solution

●

Can attain 5% TDD per load or bus inside the plant

●Guarantees 5% THDv

●Requires 3% impedance at loads

●Selection based upon loads

●

Easy to use on-line tool

●www.squaredleantools.com

http://www.squaredleantools.com/

http://www.squaredleantools.com/




Thank You !

Questions?

power quality and harmonic mitigation

Documents