Diapositive 1Wu Guopei
China
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
China is speeding up the infrastructure of smart grid
Main characteristics of Smart grid
self-healing and adaptive
Smart Grid in China
WU– CHN – RT 3b
Adaptive
Automatically recover to normal state with minimum manual intervention
New Challenges for Smart Grid Protection
WU– CHN – RT 3b
grid protection
First defense line Conventional relay protection
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Change from relay protection to grid protection
Second defense linePower stability control system
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Frankfurt (Germany), 6-9 June 2011
Third defense lineemergency control
Designed to prevent from system collapse and large area blackout using out-of-step islanding and frequency & voltage control.
Change from relay protection to grid protection
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Concept of grid protection
Safe and realtime information exchange
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Concept of grid protection
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Research 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.
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Research of grid protection
Fast power recovery in regional power grid
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Research 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.
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Research 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
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Case 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
WU– CHN – RT 3b
The goals: average fault outage time 5.2min/year
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Implementation 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.
WU– CHN – RT 3b
Frankfurt (Germany), 6-9 June 2011
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.
WU– CHN – RT 3b
Implementation of Grid protection
Frankfurt (Germany), 6-9 June 2011
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.
WU– CHN – RT 3b
Implementation of Grid protection
Frankfurt (Germany), 6-9 June 2011
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.
WU– CHN – RT 3b
Implementation of Grid protection
WU– CHN – RT 3b
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