Frankfurt (Germany), 6-9 June 2011 Smart Grid Protection in China Wu Guopei Guangzhou Power Supply Bureau Guangdong Power Grid, China

Frankfurt (Germany), 6-9 June 2011  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 Contents

Frankfurt (Germany), 6-9 June 2011  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 Smart Grid in China WU– CHN – RT 3b

Frankfurt (Germany), 6-9 June 2011  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 New Challenges for Smart Grid Protection WU– CHN – RT 3b

Frankfurt (Germany), 6-9 June 2011 Change 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.

Frankfurt (Germany), 6-9 June 2011 Change from relay protection to grid protection Second defense line ： Power stability control system To avoid system out-of-step by applying load shedding and generator shutdown according to pre-set control tactic.

Frankfurt (Germany), 6-9 June 2011 Third defense line ： emergency 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

Frankfurt (Germany), 6-9 June 2011 Concept 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.

Frankfurt (Germany), 6-9 June 2011 Concept of grid protection  Goal ： Realize integrated and optimized protection and control tactic instead of isolated three-defense line protection system

Frankfurt (Germany), 6-9 June 2011 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. Accurate fault locate and precise fault isolation can be achieved by using wide area fault distinguishing information at each node.

Frankfurt (Germany), 6-9 June 2011 Research 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.

Frankfurt (Germany), 6-9 June 2011 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. 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.

Frankfurt (Germany), 6-9 June 2011 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 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.

Frankfurt (Germany), 6-9 June 2011 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  Build distributed Intelligent Self-Healing Control System Based on Multi-Agent  The goals: average fault outage time 5.2min/year

Frankfurt (Germany), 6-9 June 2011 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

Frankfurt (Germany), 6-9 June 2011 WU– CHN – RT 3b Thank you for your attention !