Renewable Energy Generation: Challenges and Practices · 9/7/2018 · Wind & Solar Energy...
Transcript of Renewable Energy Generation: Challenges and Practices · 9/7/2018 · Wind & Solar Energy...
Renewable Energy Generation:
Challenges and Practices
CHEN Guoping
State Grid Corporation of China (SGCC)
Sep 7, 2018
Contents
2
1. Developments of Renewable Energy in SGCC
2. Challenges on Large-scale Wind and Solar
Power Integration
3. Work carried out and proposed by SGCC
Introduction of SGCC
SGCC is the world’s largest public utility company which serves over 1.1 billion people and
covers 88 % of the Chinese territory.
By July 2018, the total generating capacity installed in SGCC’s service area had reached 1427 GW.
The maximum load in SGCC’s service area reached a historical high at 810 GW on July 25, 2018.
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Generating capacity by energy source (July 2018)
Coal
799GW, 56.9%
(▲3.6%)
Hydro
225GW, 16.0%
(▲2.0%)
Wind
137GW, 9.8%
(▲11.5%)
Nuclear
23GW, 1.6%
(▲10.1%)
Solar
142GW, 10.1%
(▲41.9%)
Gas
60GW, 4.2%
(▲7.7%)
Other thermal
42GW, 3.0%
(▲10.5%)
Load curve on July 25, 2018GW
550
600
650
700
750
800
850
0:00 4:00 8:00 12:00 16:00 20:00 24:00
Promoting UHV Power Transmission
China’s coal, wind and solar energy resources concentrate in the Three-North areas, while hydro power
resources are mainly located in the southwest. However, over 70% of electrical load resides in Central
and East China. SGCC actively promotes the ultra-high voltage (UHV) power transmission to facilitate
large-scale, long-distance allocation of energy resources. It has constructed 11 UHV DC projects with a
total length of over 40,000 km, and the interregional transmission capability exceeds 96 GW.
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HVDCUHVDC
From Russia
To South China
Northeast
NorthNorthwest
East
SouthwestCentral
Northwest coal,
wind & solar
power base
North and
Northeast coal
and wind power
bases
Southwest hydro
power base
Load
center
The ongoing Changji-Guquan
project is the world's state-of-
the-art UHV DC project with
the highest voltage (±1100 kV),
the largest capacity (12 GW)
and the longest transmission
distance (3324km).
北京天津
重庆
冀南山西
辽宁
吉林
黑龙江
江苏
浙江
安徽
福建
江西
山东
河南
湖北
湖南
广东
海南
四川
贵州
云南
陕西甘肃
青海
台湾
蒙西
广西
西藏
宁夏
新疆
上海
蒙东
冀北
Renewable Power Generation
In 2011~2017, the average annual growth of hydro, wind and solar power generating
capacity were 6%, 24% and 93%, respectively. By July 2018, SGCC has 504 GW of
renewable power generation installed in its service area (225 GW hydro, 137 GW wind,
142 GW solar with 39 GW distributed PV).
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0~20
20~50
50~100
100~200
>200 Unit: GW
Renewable power generation in SGCC
156169
185199
208 216224 225
3547
7088
103117
129 137
2 315
2436
67
115
142
0
30
60
90
120
150
180
210
240
2011 2012 2013 2014 2015 2016 2017 2018
Hydro/水电 Wind/风电 Solar/光伏
GWWind & solar power in provincial grids
Wind & Solar Energy Consumption
In 2011~2017, the average annual growth of wind and solar energy consumption were
26% and 134%, respectively. In 2018, wind and solar energy accounted for 8.4% of the
total electricity generation in SGCC by August; the growth rate of wind and solar energy
consumption (38.4%) was much higher than that of total electricity consumption.
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5779
129145
166183
233
1 3 823
3856
101
0
50
100
150
200
250
2011 2012 2013 2014 2015 2016 2017
Wind/风电 Solar/光伏
GWhRenewable energy generation in SGCC
Contents
7
1. Developments of Renewable Energy in SGCC
2. Challenges on Large-scale Wind and Solar
Power Integration
3. Work carried out and proposed by SGCC
Difficulties on Load Following
The volatility of wind power output results in difficulties on load following. In 2017, the total wind
power output in SGCC varied from 63 to 7.9 GW, and the maximum intraday variation reached 32 GW.
China heavily relies on coal power with limited regulation capability, while flexible power sources
contributes a very small portion. The grid regulation capability further reduces during heating period.
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Load
(GW)
Wind
(GW)
Load and wind power in Northwest China, March 2018
In March 2018, the wind power
output in Northwest China grid
varied from 2 to 31 GW, and the
maximum intraday variation reached
17.72 GW.
0
5
10
15
20
25
30
35
50
55
60
65
70
75
80
85
0:00 4:00 8:00 12:00 16:00 20:00
Challenges from Power Electronics
Wind and solar power generation is integrated into the system via power electronic
components, which lacks active/reactive power regulation abilities. As conventional
generators are replaced by wind and solar power, the system presents weaker inertia,
damping and robustness to grid disturbances. This is a large challenge to the security and
stability of the system.
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The evolution of power system in China
Inertia from
conventional
generators
Grid in the past Present and future grid
100% conventionalConventional<70%
Wind & solar>30%
Inertia from
conventional
generators
Lost inertia
Intolerance to Grid Disturbances
Wind and solar power generation lacks tolerance to grid disturbances such as high frequency and
high/low voltage. It may be off the grid after a grid fault and worsen the situation.
In January 2014, the transient overvoltage (128%Un) caused by a Tianshan-Zhongzhou UHVDC fault resulted in the
loss of 25 wind turbines by overvoltage protection in Qiaowan wind farm which is 400km away from Tianshan
station.
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Comparison of tolerance levels of wind turbines and
coal-fired generators
Wind Coal-fired
Overvoltage 1.1 p.u. 1.3 p.u.
Overfrequency 50.2Hz 51.5Hz
Primary frequency
responseNone 6%
Power factor0.95 leading
~0.95 lagging
0.95 leading
~0.85 lagging
Overvoltage caused by Tianshan-Zhongzhou UHVDC
fault (PMU recordings)
128%Un
Grid Oscillation Problems
Multi-form sub/super-synchronous oscillations (SSOs) are likely to occur in a
weak grid with high wind power penetration.
Since 2015, more than 100 SSOs have happened near Tianshan-Zhongzhou UHVDC
converter stations and wind farms in Hami, Xinjiang.
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至汗海
照阳河牧场
鹿原
白龙山
长青
博丰
华锦东山
乌登山
国华佳鑫
麒麟山义缘站
韩家庄
金阳
永发
宏达东湾
坝头
察北站中宝
九龙泉
沽源
至太平
恒泰
冰峰
莲花滩
桦树岭
秋林
风电场
500kV变电站
200kV变电站
固定串补
500kV线路
200kV线路
Wind power oscillations in Guyuan, Hebei SSOs triggered by wind power in Hami, Xinjiang
Contents
12
1. Developments of Renewable Energy in SGCC
2. Challenges on Large-scale Wind and Solar
Power Integration
3. Work carried out and proposed by SGCC
Analyzing Grid Characteristics
SGCC performs researches and innovations on basic theory, grid control and simulations,
which improves the recognition of grid characteristics.
Construct the world’s largest hybrid analog/digital real-time power system simulation platform
and the first 900-Tflops supercomputing platform designated for power system simulation.
Conduct hybrid electro-mechanical/electro-magnetic transient simulations to accommodate the
trend of power-electronization of power systems.
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Supercomputer center Verification of UHV DC simulation models
Enhancing and Utilizing Transmission
Continuously strengthen the grid to improve long-distance power transmission capability.
Establish market mechanisms to reduce the number of online fossil-fuel power units and give full
play to their regulation capabilities.
Closely monitor and effectively utilize the grid regulation capabilities and the available transmission
capacity of tie-lines to consume renewable energy to the maximum extent.
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Real-time grid balance monitoringProspective interregional grid in 2030
Improving Regulation Capability
Support the upgrade of coal-fired generators to allow lower minimum load levels for wider ranges
of power output adjustments.
Promote grid-scale energy storage and expedite the construction of pumped-hydro plants. Over
24 GW of pumped hydro is expected to be in service by 2020.
Establish power balancing mechanism with distributed energy storage and demand response, and
make room for renewable energy through markets of generation rights and ancillary services.
15Minimum load level of coal-fired generators Power balance affected by demand-side management
Wind + solar
Load without demand-
side management
Load with
demand-side
management
Load/Generation
Time
0%
20%
40%
60%
80%
100%
China/中国 Denmark/丹麦 Germany/德国
Promoting Grid-friendly Wind & Solar Power
Revise the grid code compliance to include high/low voltage ride-through (LVRT/HVRT)
requirements for wind turbines, and construct testbeds to support the upgrade of wind turbines
for LVRT/HVRT capabilities.
Conduct researches on primary frequency response (PFR) capability of wind turbines and wind
farms, and carry out experiments in Northwest China grid.
Promote virtual synchronous generator (VSG) control of wind turbines and PV units to enable
grid-friendly capabilities including inertia, damping, PFR and reactive voltage regulation.
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Frequency Pper
49.4
49.6
49.8
50.0
50.2
50.4
50.6Hz
150
200
250
300
350
400
450
500
550
600
650
700kW
0 5 10 15 20 25 30 35 40 45 50 55
sFref Pact Pref
49.75
49.80
49.85
49.90
49.95
50.00
50.05
50.10Hz
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5MW
0 10 20 30 40 50 60
s
PFR test on wind turbines and
wind farms
VSG control of PV inverters
130%Un_500ms
125%Un_1s
120%Un_10s
115%Un_10s
110%Un_∞
Revised requirements on LVRT/HVRT
of wind turbines
PI
Udc
Umppt
Pm
E0
Pmppt
kqEref
无功调节
有功调节
AVR
kf
ua
ub
uc
Qref
Uac
Q
ωref
ω
Uac_ref
定子电流闭环及调制
P
功率计算
Pref
1/s-+
-1/Js
+0
D
sin
sin( 2 / 3)
sin( 2 / 3)
1/Ls
R
uabc
+
--
P、Q
VSG本体模型
Eabc
Pprim
Conclusion and Outlook
By 2030, wind and solar power in SGCC is expected to make up 30% of generating capacity
and 16% of electricity generation; the proportion will further rise to 50% and 30% by 2050.
SGCC will dedicate to a next generation power system with better connectivity, intelligence,
flexibility and safety, and actively promote the development of renewable power to
support China’s transformation towards clean and low carbon economy.
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60% 54%39% 33%
17%
11% 21%
30% 37%52%
0%
20%
40%
60%
80%
2015 2020 2030 2035 2050
Fossil fuel/火电 Wind + solar/新能源
66% 64%54% 47%
29%
4% 9%16%
20%
34%
0%
20%
40%
60%
80%
2015 2020 2030 2035 2050
Fossil fuel/火电 Wind + solar/新能源
Generating capacity 2015~2050 Electricity generation 2015~2050
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Thank you for attention!