INTRODUCTION OF INTRODUCTION OF ULTRA-HIGH VOLTAGE (UHV) ULTRA-HIGH VOLTAGE (UHV)

1000 kV AC TRANSFORMER1000 kV AC TRANSFORMER

Presented By

Zhijin ChenTBEA Shenyang Transformer Group Co. Ltd. China

Structure of 1000kV AC Structure of 1000kV AC Transformer Transformer

Parameters Parameters of of

1000kV/1000 MVA UHV AC 1000kV/1000 MVA UHV AC Transformer Transformer

Made by TBEA, ChinaMade by TBEA, China

1) Rated Capacity

HV Winding ： 1000 MVA

MV Winding ： 1000 MVA

LV Winding ： 334 MVA

2) Rated Voltage

HV Winding ： 1050/√3kV

MV Winding ： 525/ √3 ±4×1.25%kV

LV Winding ： 110kV

3) Rated Frequency ： 50Hz

4) Three-phase Connection Symbol ： YNa0d11

5) Nominal Short-circuit Impedance (based on 1000MVA) ： HV － MV ： 18%

HV － LV ： 62%

MV － LV ： 40%

6) Type of Cooling ： Main Transformer - OFAF

Voltage-regulating Transformer - ONAN

7) Temp. Rise Limit Value ：

Winding ： 65K

Top Oil ： 55K

Hot-spot: 78K

Tank Surface ： 80K

8) Total weight of Main Transformer ： 535 ton

Total weight of Voltage-regulating Transformer ： 143 ton

9) Internal Insulation Level ：

 

Rated Short-time Power-frequency

Withstand Voltage (r.m.s.

value ， 5min ）

Rated Switching Impulse Withstand Voltage （ relative

peak value ）

Rated Lighting Impulse Withstand Voltage （ peak

value ）

Full WaveChopped

Wave

HV 1100 kV 1800 kV 2250 kV 2400 kV

 

Rated Short-time Power-frequency

Withstand Voltage （ r.m.s. value ，

1min ）

Rated Switching Impulse Withstand

Voltage (relative peak value)

Rated Lighting Impulse Withstand Voltage (peak

value)

Full WaveChopped

Wave

MV 630 kV 1175 kV 1550 kV 1675kV

Neut. 140 kV / 325 kV /

LV (Tert.)

275kV / 650 kV 750 kV

Technical Applied Technical Applied on on

Design and Production Design and Production of of

1000kV/1000 MVA UHV AC 1000kV/1000 MVA UHV AC TransformerTransformer

-- Main Insulation

-- Longitudinal Insulation

-- 1000kV Leads

-- Magnetic Leakage & Losses

-- Winding Temp. Rise

-- Short-circuit Withstand Capability

-- Strength of Tank Transportation

-- Seismic Strength

Key Technical Characteristic Studies——Longitudinal Insulation

Potent i al Di st r i but i on undedr Ful l Wave I mpusl e

0

0. 2

0. 4

0. 6

0. 8

1

1. 2

0 10 20 30 40 50us

oten

tial

of

Full

Wav

e Im

puls

e Vo

ltag

e %

G1 G2 G4G10 G18 G24G26

Gradient voltage distribution under full wave lighting impulse-0. 04

-0. 02

0

0. 02

0. 04

0. 06

0. 08

0 5 10 15 20 25 30 35 40 45 50usFu

ll w

ave

impu

lse

volta

ge (%

)

HV wi ndi ng 1 oi l -ductHV wi ndi ng 3 oi l -ductHV wi ndi ng 5 oi l -ductHV wi ndi ng 7 oi l -duct

Creepage gradient distribution under full wave lighting impulse-0. 15

-0. 1

-0. 05

0

0. 05

0. 1

0. 15

0. 2

0. 25

0 5 10 15 20 25 30 35 40 45 50

us

Full

wav

e im

puls

e vo

ltage

(%)

Impulsive creepage gradient distribution ofHV winding (first 100mm)

Impulsive creepage gradient distribution ofHV winding (first 200mm)

Impulsive creepage gradient distribution ofHV winding (first 300mm)

Gradient distribution under chopped wave lighting impulse- 0. 03

- 0. 02

- 0. 01

0

0. 01

0. 02

0. 03

0. 04

0. 05

0. 06

0. 07

0 5 10 15 20 25 30 35 40 45 50us

Cho

pped

wav

e im

puls

e vo

ltage

(%)

HV wi ndi ng 1 oi l - ductHV wi ndi ng 3 oi l - ductHV wi ndi ng 5 oi l - ductHV wi ndi ng 7 oi l - duct

Potential distribution under chopped wave lighting impulse-0. 4

-0. 2

0

0. 2

0. 4

0. 6

0. 8

1

0 5 10 15 20 25 30 35 40 45 50usC

hopp

ed w

ave

impu

lse

pote

ntia

l (%

)

G1 G2 G4

G10 G18 G24G26

Electric field intensity distribution at the middle part between LV and HV windings

Electric field intensity distribution at the end between

LV and HV windings

Electric field intensity distribution of main insulation

calculation by utilizing ANSOFT at the end between

LV and HV windings

Electric field intensity distribution of main insulation

calculation by utilizing ANSOFT at the middle part

between LV and HV windings.

Key Technical Characteristic Studies——1000 kV Leads

—Magnetic Leakage & Losses

5 Limb Core with 3 Parallel Wound Legs Required Stringent Quality Control to Prevent Circulating Current Losses

Key Technical Characteristic Studies——Winding Temp. Rise

Key Technical Characteristic Studies——Short-circuit Withstand Capability

Axial forces on a disc of a winding during short circuit

TV winding radial and axial leakage flux distribution

——Strength of Tank Transportation

Diagram of tank metamorphose under transportation condition

Enlarged diagram of tank stress under

transportation condition

——Seismic Strength

Diagram of stress distribution under

earthquake situation

Diagram of transformer bushing displacement response

during earthquake….long bushing needed special analysis

Some Testing Results Some Testing Results on on

The Product The Product of of

1000kV/1000 MVA UHV AC 1000kV/1000 MVA UHV AC TransformerTransformer

Required Value Product Trail Value

HV Partial Discharge Level

≤100pc 25pc

MV Partial Discharge Level

≤200pc 60pc

LV Partial Discharge Level

≤300pc 20pc

Required Value Product Actual Value

Top Oil Temp. Rise 55K 25K

HV Winding Temp. Rise 65K 45K

MV Winding Temp. Rise 65K 53K

LV Winding Temp. Rise 65K 49K

Tank Hot Spot Temp. Rise

80K 40K

No-load Audible Sound 75dB(A) 74dB(A)

Load Audible Sound 75dB(A) 75dB(A)

Total losses tested

Guarantee Final Test

Load loss, kW 1580 1477.7

No load loss, kW 200 199.9

The construction of The construction of

China’s first 1000kVChina’s first 1000kV

UHV transmission UHV transmission

project was project was

completed completed

successfully in 2008, successfully in 2008,

and passed 168-hour and passed 168-hour

full load energized full load energized

performance test in performance test in

January 2009.January 2009.

Thank You!Thank You!

TBEA Shenyang Transformer Group Co., Ltd.

TBEA Shenyang Transformer Group Co., Ltd.