Title: Smart%20Grid%20Protection%20in%20China
1Smart Grid Protection in China
Wu Guopei Guangzhou Power Supply Bureau Guangdong
Power Grid, China
2Contents
- Smart grid in China and the challenge for
protection - Change from relay protection to grid protection
- Concept of grid protection system
- Reach of grid protection
- Case study
3Smart Grid in China
- China is speeding up the infrastructure of smart
grid - Main characteristics of Smart grid
- self-healing and adaptive
- safe, stable and reliable
- fine compatibility
- high quality and efficiency
- coordinated and economic
- friendly interaction with the users
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4New Challenges for Smart Grid Protection
- Adaptive
- Flexible topology structure
- Connection with distributed generators
- Self-healing
- Preventive control under normal operation
condition - Automatically recover to normal state with
minimum manual intervention
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5Change from relay protection to grid protection
- Three-defense line for the safety of power system
- First defense line Conventional relay protection
-
- To safeguard power system stable operation by
fast and selective tripping of fault elements.
6Change from relay protection to grid protection
- Second defense linePower stability control
system -
- To avoid system out-of-step by applying load
shedding and generator shutdown according to
pre-set control tactic.
7Change from relay protection to grid protection
- Third defense lineemergency control
-
- Designed to prevent from system collapse and
large area blackout using out-of-step islanding
and frequency voltage control.
8Concept of grid protection
- Possibility grid protection
- Development of information and storage technology
eliminates the information isolated island in
power system. - Safe and realtime information exchange
- Extension from substation domain information
interaction to power grid wide area information
interaction.
9Concept of grid protection
- Goal
- Realize integrated and optimized protection and
control tactic instead of isolated three-defense
line protection system
10Research of grid protection
- Optimized protection performance
- Limit of conventional protective relay The
selectivity of protective relays, especially back
up protective relays, are dependent on the
current, impedance and time settings, which may
cause operation time delay and loss of
selectivity. - Accurate fault locate and precise fault isolation
can be achieved by using wide area fault
distinguishing information at each node.
11Research of grid protection
- Fast power recovery in regional power grid
- When the substation is loss of power due to power
supplies out-of-service, the power supply in
other substations will be connected according to
system operation mode and topology state.
12Research of grid protection
- Improve the safety and reliability of
distribution network after power recovery - Overload caused by power recovery may affect the
power grid reliable operation - Load shedding shall be adopted to ensure the
power supply to important consumers. - Acquire pre-fault static load information through
the wide area information interaction with EMS,
and optimize load shedding strategy to maximally
protect reliable power supply.
13Research of grid protection
- Improve the safety and reliability of
distribution network with distributed power
supply - When distributed power supplies are connected to
distribution network, the conventional relay
setting regulations can not meet the requirements
of system selectivity. - The electrical character are varying according to
the type of distributed power supplies during
system fault and grid interconnection. - Fast and precise fault locate and fault tripping
using wide area measurement data - Check if the distributed power supply can
restored to interconnection or isolated island
state after fault is cleared, and ensure the safe
and reliable operation of distribution network by
applying grid interconnection control and load
shedding.
14Case study Grid protection distribution network
in China Southern Grid
- Located in financial high-tech service area of
Guangdong - Includes 2 substations, 65 kilometers
distribution lines, 58 switch room ring main
- Build distributed Intelligent Self-Healing
Control System Based on Multi-Agent - The goals average fault outage time 5.2min/year
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15Implementation of Grid protection
- Taking into account the real-time performance of
feeder automation devices (FA) and information
completeness of distribution automation system
(DMS), to raise the smart level of real-time
control. - Distribution terminals with enhanced functions
will be used as agents of grid protection and
control system, to realize local signal
acquisition pre-treatment, logic determination
and implementation of remote commands.
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16Implementation of Grid protection
- Embedded central control stations with rapid
information processing ability will be set up,
for fault criteria logic calculation based on
wide-area information, to realize rapid fault
location. - System configuration tool shall be provided with
graphic interface to realize system configuration
for IEDs of smart distribution network protection.
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17Implementation of Grid protection
- Wide-area information protection logics such as
improved directional pilot protection suitable
for distribution grid will be used, to
effectively determine distribution grid fault
zone connected with distributed power source at
load terminals.
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18Implementation of Grid protection
- Realize power restoration path selection function
based on grid topology, assisted with load
control technologies such as LF load
disconnection, to realize rapid load restoration
and load optimization and re-distribution. - Micro-grid frequency and load control technology
with multi-DG access will be tried, for
distribution grid multi-DG coordination control
in island operation.
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19Thank you for your attention !
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