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 Protection in China

Wu GuopeiGuangzhou Power Supply Bureau

Guangdong Power Grid,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

Case study

Contents


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


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

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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.



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.


Third defense line ： emergency control Designed to prevent from system collapse and

large area blackout using out-of-step islanding and frequency & voltage control.



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.


Concept of grid protection

Goal： Realize integrated and optimized

protection and control tactic instead of isolated three-defense line protection system


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.



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.



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.


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.


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


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


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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Implementation of Grid protection

Real-time Network

配置工具Embedded ControlDevice

Agent Agent Agent

System Configuration

Tool


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



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



WU– CHN – RT 3b

Thank you for your attention !

Documents

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