11

Intelligent LRS (GZYQ) introduction

22Power ≤2000kWPower ≤2000kW Power Power ＞＞ 2000kW2000kW

GZYQ series: GZYQ series: used for soft starting of 3.3kV~ 15kV used for soft starting of 3.3kV~ 15kV synchronous or squirrel cage motorssynchronous or squirrel cage motors

Intelligent LRS (GZYQ) brief

33

M

QS1

QF1

QF2

PC

M

PLC

VFD

A/D

RS

P I D

Work principle of LRS (GZYQ)

H.V. H.V. switch panelswitch panel

H.V. H.V. Neutral panelNeutral panel

Intelligent LRSIntelligent LRS

Take an example of GZYQ-3000/11-Y Take an example of GZYQ-3000/11-Y for 11kV,3000kW squirrel cage motor (neutral point can be open)for 11kV,3000kW squirrel cage motor (neutral point can be open)

44

Resistance principle:

R=ρlS

Animation of intelligent LRS(GZYQ)

55

Change in distance between fixed electrode and moving electrode leads to the change of liquid resistance

Animation of intelligent LRS(GZYQ)

66

Single line diagram of GZYQ- (line side)△

H.V. switch Panel

LRS

Switch panel

M

QS1

QF1

QF2

Rs

77

M

H.V. switch Panel

LRSH.V.

neutral panel

QS1

QF1

QF2

Rs

Single line diagram of GZYQ-Y (neutral side)

88

M

Other load

B1

11kV

S d min=188 MVA

Sbe=16 MVA

S fh=5 MVAcos φ fh=0 . 9sin φfh=0 . 436

Ud%=7.5

load

power network diagram

Parameters required for calculation:

1、 network parameter

2、motor parameter

3、 load parameter

990 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.82

n/nN

T/TN

U/UN=0.6

U/UN=0.7

U/UN=0.8

U/UN=0.9

U/UN=1

Torque and speed curve

T U∝ 2GZYQ torque & speed curveGZYQ torque & speed curve

1010

1500

I( A )

10 20 30 40 500 t (s)

750

5 15 25 35 45

D.O.L. starting current curve

GZYQ starting current curve

Starting current: GZYQ vs D.O.L.

Comparison between GZYQ and D.O.L. start

1111

Original torque & speed curveOriginal torque & speed curveRR11>R>R22>R>R33>R>R44ss

00

nn11

11

nnmm ssmm

Torque & speedTorque & speed curve: GZYQ vs reactor

Comparison between GZYQ and reactor

GZYQ torque & speed curveGZYQ torque & speed curve

1212

Reference: Oxygen plant of Goyal Gases Reference: Oxygen plant of Goyal Gases

1313

Reference: Oxygen plant of Goyal GasesReference: Oxygen plant of Goyal Gases

1414

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