developments of dc transmission & distribution technology ... · 2 hvdc projects in china...

Developments of DC Transmission &

Distribution Technology in China

Mingming SHI

State Grid Corporation of CHINA

Contents

1. State Grid Introduction

2. HVDC Projects in China

3. Motivation for MVDC & LVDC

4. MVDC & LVDC Projects

5. Standardization Activities

6. Expecting Cooperation

SGCC Introduction

Fortune Global 500 RankServes of China’s

national territoryPower supply population

State Grid Corporation of China（SGCC） established on

December 29, 2002.

State Grid supplies power to over 1.1 billion population in 26

provinces, autonomous regions and municipalities, covering

88% of Chinese national territory.

1

SGCC Introduction1

SGCC Introduction1

Organizational Structure

30 Headquarter Offices

Administration Office, General Office, Strategic Research Office, Department of

Development and Planning, Department of Finance & Asset, Department of Safety

Supervision, Department of Operation & Maintenance………

27 Provincial Subsidiaries

Beijing, Tianjin, Hebei, Jibei, Shanxi, Shandong, Shanghai, Jiangsu, Zhejiang …

6 Branches

State Grid North China Branch, State Grid East China Branch

State Grid Central China Branch, State Grid Northeast China Branch

State Grid Northwest China Branch, State Grid Southwest China Branch

38 Other Subsidiaries Directly Managed by State Grid

SGCC Introduction1

SGCC Introduction1

By now, State Grid has established offices or branches in

more than 20 countries and regions, including Ethiopia,

Brazil, Pakistan, Egypt, Turkey and the Lao PDR .

SGCC Introduction1

SGCC are committed to electrification and

energy connectivity, meeting the power

demand with clean and green alternatives.

At the present time, SGCC is facing with

problems, such as:

➢ The adjustment of electricity tariffs

➢ The reform of electric power system

➢ The opening of electric power market

The Chairman of SGCC Mr. KOU proposed the “Three-Function

and Two-Network” strategy to transfer a traditional electricity

seller to an Energy Internet Enterprises.

SGCC Introduction1

Platform

based

Sharing

based

EnergyHub

based

◼ Definition of Three-Function

SGCC Introduction1

IoT

Strong Smart Grid ◼ Ubiquitous power IoT Architecture

Contents







HVDC Projects in China2

2.1 LCC-HVDC Survey


The maximum UHVDC transmission capacity is up to 10000MW（Ximeng⁃Taizhou ±800 kV project）.

The heart of UHVDC project is converter valve, the rated current is 6250A.

DC LineRectifier station Inverter station

2.2 LCC-HVDC Structure


17.48 Hectare

2.3 LCC-HVDC Station Area


◆ Commutation failure is one of the most common failures

for LCC-HVDC transmission system.

◆ The converters of the HVDC system yield harmonic

voltages and currents because of its non-linearity.

◆ Absorbing large reactive power, mostly, 40%~60% of

the rated power.

◆ Because of passive filter and reactive power

compensator, LCC-VSC occupies large area.

2.4 LCC-HVDC Characteristics


Sub module

Valve tower

Valve section

Valve hall

iPa

Ua1

Ua2

Uan

Va1

+

-

+

-Va2

+

-Van

ipb

Ub1

Ub2

Ubn

Vb1

+

-

+

-Vb2

+

-Vbn

ipc

Uc1

Uc2

Ucn

Vc1

+

-

+

-Vc2

+

-Vcn

Va(n+1)

+

-

+

-Va(n+2)

+

-Va(n+2)

iNa

Vb(n+1)

+

-

+

-Vb(n+2)

+

-Vb(n+2)

iNb

Vc(n+1)

+

-

+

-Vc(n+2)

+

-Vc(n+2)

iNc

id

Ud O

P

N

ab c

Vsa+ -Rs

Rs

Rs

isa

isb

isc

Ls

Ls

Ls

Vsb+ -

Vsc+ -

D2

+

E

T1

T2

D1

Vjk

➢ Interconnection between

nonsynchronous AC system

➢ urban power supply

➢ interconnection of islands

➢ Black Start

2.5 VSC-HVDC Survey


Station Capacity /MW AC voltage /kV DC voltage /kV

ZHOUSHAN 400 220 ±200

DAISHAN 300 220 ±200

QUSHAN 100 110 ±200

SIJIAO 100 110 ±200

YANGSHAN 100 110 ±200

Each converter station adopts

modular multi-level converter(MMC),

and the converter stations are

connected by a total of 140 km

submarine cable.

2.6 ZHOUSHAN VSC-HVDC Project


Zhangbei ± 500 kV VSC-HVDC demonstration

power transmission project is the first one to

build VSC HVDC transmission power grid.

2.7 ZHANGBEI VSC-HVDC Project

Contents







Motivation for MVDC & LVDC3

Transition is happening…

3Motivation for MVDC & LVDC

3

Renewable Energy Distribution Network

MVDC Application:

Rail Transportation Shore Power

LVDC Application:

Motivation for MVDC & LVDC

Contents







4.1 SUZHOU Renewable Energy Town

4.2 SHENZHEN Low Carbon Building

4.3 BEIJING Xiaoertai Flexible Substation

4.4 NANJING Golden Corporation LVDC Building

MVDC & LVDC Projects4



Multi-type distributed renewable energy source of

2.956 MW and DC load of 1.8 MW have been built in

Tongli Demonstration Zone, SUZHOU.

Distributed

Renewable

Energy

2.9 MW

External

power

supply

WG 20 kW

Solar Thermal 25 kW

Battery 700kW/ 1h

PV 2.911 MW

Thermal Storage

28.8 MJ

DC Load

1.2 MW

AC Load

Data Center 200kW

Residential Load

101kW

EV-Charger 600kW

DC Air-condition

300kW

DC Load 3kW


Supported by 2017-2020 National key

research project

《AC / DC hybrid renewable energy

technology based on power electronic

transformer》




◼ Power Electronic Transformer Topology

◼ Si-IGBT PET

◼ SiC PET


◼ Fault Current Limiter


Fault Current Limiter(FCL) is another key

DC equipment, which can limit fault current

by series connection to the power grid. 750V+

750V−

F1

C1 R2L1

S1+

S2+

S3+

S4+

S5+

S6+

S7+

S8+

S9+

S10+

S11+

S12+

C2 R3

R4 D1

L2

L3

C3

C4

L4 C8

R9

S13+

ZD1

S1-

S2-

S3-

S4-

S5-

S6-

S7-

S8-

S9-

S10

S11-

S12-

C6 R8

D2

S13-

ZD2

L5

L6

C7

C5

F3

R7

R5

R10

Parallel Side Series Side Filter Side


◼ Fault Current Experiment◼ 750V-Port Current Waveforms


◼ PET Active Power Waveforms


Sino-US Low Carbon Building and Community

Innovation Experimental Center

Shenzhen Institute of Building Research Co., Ltd.

focused on following fields:

◆ Prefabricated Construction

◆ DC building + Intelligent micro-grid,

◆ Indoor Environment Quality,

◆ Policy and Market Mechanism Research



1 LED Lighting 4.4 kW

+375V

BUS2 48V socket 4.4 kW

3 375V socket 10 kW

4 EV-charger 30 kW

5 LED Lighting 4.4 kW

-375V

BUS

6 48V socket 4.4 kW

7 375V socket 10 kW

8 Data Center 40 kW

9 Public Lighting 4 kW

10 Emergency Lighting 4 kW

11 Security system 8 kW

12 DC Air Conditioner 159 kW750V

Bus

◆Regular contact area, vertical less than

2 meters; low-power high-frequency use

of electrical appliances, power less than

100W, support hot-plug.

◆Daily activity area, vertical more than 2

meters; medium power, less plug-in

frequency of electrical appliances;

compatible with 220V AC equipment.

◆Public area, professional operation and

maintenance; high power, low contact

frequency.



◼ Topology of Flexible Substation ◼ Zhangbei Alibaba Data Center

◼ Valve Hall

4.3 BEIJING Xiaoertai Flexible Substation


4.4 Golden Corporation LVDC Building

AC/DC DC/DC DC/DC

DC Charger Active Protection

Flexible DC/DC

Active Protection Active Protection


4.4 Golden Corporation LVDC Building

◆ Test for typical DC appliances in DC buildings

◆ Protection equipment and control strategy research

◆ Power quality research in DC grid

0 200 400 600 800 1000 1200 14000

0.5

1

1.5

2

Um

f(V)

各频率纹波分量振幅的 95%概率大值

0 200 400 600 800 1000 1200 14000

0.5

1

1.5

2

Um

f(V)

f(Hz)

各频率纹波分量振幅的 99%概率大值

◼ 95% Probability Value

◼ 99% Probability Value

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

229.55

229.6

229.65

229.7

229.75

229.8

229.85

229.9

229.95

230

2018年 2月 11日 16时 12分 43.8秒 220V直流母线电压有效值趋势

t (h)

Urm

s(V)

◼ 220V Bus Voltage Amplitude

Contents







Standardization Activities5

2017.10： IEC TC8 WG9 established

in Vladivostok GM, Russia. IEC TC8

WG9 called experts together to

dedicate to the standardization work

of LVDC distribution.

2018.05： Partly participated in the

general meeting of SyC LVDC

meeting and made a presentation

about the voltage level and PQ

phenomena in LVDC distribution.


2018.05.11~13 IEC TC8 WG9

kick-off meeting in Nanjing. （

Joint kick-off meeting together

with SyC LVDC）

2018.10.16~17 IEC TC8 WG9

WG meeting in Busan.

Established joint working group

JWG9,managed by TC8.


2019.01.27~02.01

IEC SyC LVDC

Joint annual

meeting together

with TC8 JWG9 in

Switzerland.


According to SyC LVDC plan, TC8 WG9 is mainly devoted to low-

voltage DC distribution network. The IEC technical report “Standard

voltage and power quality Requirements for LVDC” is the first

task, and it will be the basis of a series of standards such as follow-

up planning, protection control, operation management, etc.

Contents







Expecting Cooperation6

➢ Establish DC Voltage Level and Power Quality Standard

together，such as Intelligent Home, DC Building, Electric

Vehicle, Low Voltage DC Interface and Coordination Operation

of New Energy Access.

➢ Enhance exchanges and cooperation between academies,

analyze the stability of DC network, investigate DC arc

suppression technology, promote DC community development.

➢ Sino-Japanese cooperate to build DC demonstration

projects and laboratories, jointly develop new products and

promote the application of low-voltage DC appliances.

Thanks for your attention!

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