V ariable F requency - PowerPoint Presentation

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Variable Frequency DriveDANAHER ACO5030 SVC switching Issues

August 8th, 2017

B. Ivens, F. MorantDr M. Pezzetti

A HISTORY OF SVC RELATED PROBLEMSSVC are the compensation capacitor-banks connected to the 18kV network.When these are switched on they cause transients to ripple through the networkand have a significant impact on 400VAC network and our VFD’s.

Before LS1 VFD type DANAHER K4000: Overvoltage trip during SVC only P4

During LS1 P4 upgrade QURCA/B to DANAHER ACO5030 : no more tripsDuring EYETS P8 upgrade QURCA: Enable/overload tripsK4000: Old VFD (end of life)ACO5030: New VFD

SVC P4 <> P8

P8

P4

P4: Overvoltage issues

 Resolved with ACO3050

P8: simultaneous under voltage L2, L3

 ACO3050 not suited  modification TS1 & TS2

BLOCK DIAGRAM NEW DANAHER

833

K

br

U

ond

X

Overload Fault

RInt+ext

RInt

BLOCK DIAGRAM NEW DANAHEROnduleur

Chopper

Redresseur

DC Fixe

DC Var.

AC Var.

A

C Fixe

Onduleur

mesure

U

ond

K

br

400VAC

U

Inr

R

ext

R

int

R

int

= 833

Ω

R

ext

= 15

Ω

TS1: Removed external resistance

Test SVC after

modif

:

Enable CC1,2,3

Overload CC4

Before TS1 VFD faults when SVC switch-on:

Enable CC1

overload CC2,3,4

BLOCK DIAGRAM NEW DANAHEROnduleur

Chopper

Redresseur

DC Fixe

DC Var.

AC Var.

A

C Fixe

Onduleur

mesure

U

ond

K

br

400VAC

U

Inr

R

int

R

int

= 833

Ω

Enable signal: Bus DC is loaded and VFD can start piloting the Compressor.

Enable lost when

U

inr

<

U

ond

Can be delayed (~200ms) through HW modification (insert capacitor 3.3

μ

F)

DC bus buffer too small to cope with 200ms delay

Increase buffer to 2200

μ

F,

this modification will also resolve CC4 overload problem

Tests in

labo

so far successful, test under full load this week

K4000: Old VFD (end of life)ACO5030: New VFDOverview

P4 AP4 B

P8 AP8 BType VFDACO5030ACO5030ACO5030K4000SVC FaultNoneNoneOverload/EnableNoneSVC/microcut immuneNONONO

YES

mitigation

YETS 17/18

YETS 17/18

TS2

Before install.

Danaher VFD’s are EOL and needed to be replaced.K4000  ACO5030This caused a new SVC problem.Upgrade Danaher

P4 A

P4 BP8 AP8 BType VFDACO5030ACO5030ACO5030K4000FaultNoneNoneOverloadNoneSVC/microcut immuneNONONO

YES

A history of SVC related problems PRE-LS1point

P18P2P4 A

P4 BP6 AP6 BP8 AP8 BType VFDCXSCXSK4000K4000CXSCXSK4000K4000faultNone>UNoneEarth*>U>UNone

None

AIR Liquide equipped with

Vacon

CXS

Linde equipped with Danaher K4000

*Only on one of 8 machines installed in P4



Removed network filter filter

durée de la perturbation (ms)

Suralimentation tolérée(%)

0100

30

130

SVC

Transient

121

132

K4000 DANAHER

Limite

SVC

CXS VACON

CERN SPEC:

typical voltage tolerances: +/- 5%

maximum voltage tolerances: +/- 10%

transient

overvoltages

: +50% for 10

ms

transient voltage drops: -50% for 100

ms

400VAC network

Quality

and SVC network impact & CXS solution

137.5

NXP VACON

Replace the

Vacon

CXS with

new generation NXP

Danaher VFD’s are EOL and needed to be replaced.K4000  ACO5030This caused a new SVC problem.Upgrade Danaher

P4 A

P4 BP8 AP8 BType VFDACO5030ACO5030ACO5030K4000FaultNoneNoneOverloadNone

BLOCK DIAGRAM OLD DANAHEROnduleur

Chopper

Redresseur

DC Fixe

DC Var.

AC Var.

A

C Fixe

Onduleur

mesure

U

ch

K

br

U

th

= theoretical value calculated by VFD to achieve speed

setpoint

K

br

closes when

U

ch

>

U

th

+ 30V

U

ch

will never reach this threshold value, in case of problems the motor will freewheel

and no active slowdown will be applied by VFD



Brake resistance never used

400VAC

MITIGATION NEW DANAHERRemove external resistanceDuring normal deceleration the slowdown ramp is so shallow the braking resistances

will never be used.During internal/external fault or power cut the VFD lets the motor freewheel.So before this SVC issue the resistances have never been solicited!! And thus are useless!!