LOGOSafety Through Prevention –
Safe Switching Using Smart Key Technology
Shuqiang Jin, Unitech, Zhuhai, China Nan Liu
Youru Huang, SERCC
EPRI's 14th Annual Power Switching Safety & Reliability Conference San Diego, California September 20~21, 2010
Contents
• Switching Errors and Impacts
• Traditional Prevention Approaches
• Smart Interlock System (SIS) Technology
• Development/Application of SIS in China
Impacts of switching errors:
• Supply interruptions
• Equipment damages
• Human losses
• Legal liabilities
• …
HumanError
Other……
EquipmentFailure
InadequateProcess
Switching errors can be caused by:
Common switching error types:
1. Energizing when still grounded.
2. Closing grounding switch when energized.
3. De-energizing using disconnects instead of breakers.
4. Load dropping using disconnects instead of breakers.
5. Entering energized switching bays.
Correct switching sequence is the key.
Preventative Measures:Process/Regulation:
Strict regulation and process control in all aspects of electric utility operations: design, construction, operation, personnel training and certification.
Switching order is the center piece that safeguards safe switching
Technology:Locks and interlocking devices – mechanical/electromagnetic/electrical/programmed.
Rule/topology based automated switching order generation.
Process/Regulation:Strict regulation and process control in all aspects of electric utility operations: design, construction, operation, personnel training and certification.
Switching order is the center piece that safeguards safe switching
Technology:Locks and interlocking devices – mechanical/electromagnetic/electrical/programmed.
Rule/topology based automated switching order generation.
Conventional locks and interlocks
They work to certain extent but have limitationsLack of comprehensiveness Lack of flexibility and scalabilityConstrained by complexityLack of coordination between multiple
switching within same station
………
They work to certain extent but have limitationsLack of comprehensiveness Lack of flexibility and scalabilityConstrained by complexityLack of coordination between multiple
switching within same station
………
Preventative measure attributes
1. Reliable
2. Flexible and scalable
3. Comprehensive solution to all the 5 common types
of switching errors.
4. Capable of verifying switching steps before
switching.
5. Ensures that correct switching steps are followed
during switching.
6. Easy to use and simple to install.
Smart Interlock System (SIS)
• Developed by Unitech in 1987 (Mr. Jin Shuqiang)
• Rule/logic and configuration/topology based solution.
• Programmable to suit any voltage levels and station sizes.
• Have developed vast rules base and data base capable to
accurately model complex real world situations.
• One smart key for one station
• Simulate switching to prevent switching errors.
• Enhanced by the latest computing and communication
technologies
Smart Interlock System (SIS)
SCADA Workstation/Software
Smart Key
Locks
Smart interlock System (SIS) Process
Simulate switching step on the workstation.
Switching order generation.
Transferring steps to smart key.
Perform switching steps.
Return smart key to workstation with status updates.
Simulate switching step on the workstation.
Switching order generation.
Transferring steps to smart key.
Perform switching steps.
Return smart key to workstation with status updates.
Switching Order
Open Lock
Logic/Rules/Configuration Databases
• Collect and model switching interlock logic and rules
• Collect and model single line diagram of station/system
• Logic/rules for each bay as well as inter-bay dependency in a station.
Logic DatabaseStatus Database
Software/Model Interaction
•Two databases are stored in a workstation.•The software works with models to display user interface.
•Two databases are stored in a workstation.•The software works with models to display user interface.
LogicDatabase
StatusDatabase
Human InterfaceHuman Interface Work station
Smart Key – Only Need One for Each Station
Works with both electronic and mechanical locks
Capable of multiple wireless communication protocols IrDA Zigbee CDMA/GPRS
Programmable RFID locks. Voice reminder/recorder Ambient temperature -40 ℃ to 80℃
Locks
Embedded with RFID technology
Programmed to work with the smart key
SIS Operation Cycle - Simulation
Simulation Transfer CompletionSwitching
Allowed?Status
DatabaseLogic
Database
SIS Operation Cycle - Transfer
Simulation Transfer CompletionSwitching
SIS Operation Cycle - Switching
Simulation Transfer CompletionSwitching
SIS Operation Cycle - Completion
Simulation Transfer CompletionSwitching
Example: Energize the LineBus
Disconnect #1
Disconnect #2
Breaker
STEP 1: Pre-switching Simulation
Bus
Disconnect#1
Disconnect#2
Breaker
1.Close Disconnect #1
2.Close Disconnect #2
3.Close Breaker
Switchingsequence
STEP 2: Transfer Switching Instructions to Smart Key
1.Close Disconnect #1
2.Close Disconnect #2
3.Close Breaker
Bus
Disconnect#1
Disconnect#2
Breaker
STEP 3: Perform Switching
Bus
Disconnect #1
Disconnect #2
Breaker
1.Close Disconnect #1
2.Close Disconnect #2
3.Close Breaker
1.Close Disconnect #1
2.Close Disconnect #2
3.Close Breaker
STEP 3: Perform Switching
Bus
Disconnect #1
Disconnect #2
Breaker
STEP 3: Perform Switching
1.Close Disconnect #1
2.Close Disconnect #2
3.Close Breaker
Bus
Disconnect #1
Disconnect #2
Breaker
STEP 4: Switching complete-Steps saved
Bus
Disconnect #1
Disconnect #2
Breaker
Performing switching
The unique programmed electronic ID in each RFID equipped locks ensures that only the corresponding smart key can open it. This virtually eliminates opening/closing the wrong disconnects or breakers.
SIS Benefits:
Simulation before switching identifies and eliminates potential errors
SIS
Switching Order
Switching
Switching Order
Switching
Simulation
Verification
Conventional Approach
SIS Benefits:
Multi-switching bay switching coordination
Based on safe switching logic/rules
111-3 h: 111=0,111-1d=0,111-2d=0,111-1w=0,3-7=0,111-2=0!111-3 l: 111=0,111-1d=0,111-2d=0,111-1w=0,3-7=0,111-2=0!
111-2 h: 111=0,111-1d=0,111-2d=0,111-1w=0,111-7=0,111-3=1!111-2 l: 111=0,111-1d=0,111-2d=0,111-1w=0,111-7=0,111-3=1!
SIS Benefits:
One key per station: easy to program and upgrade.
Smart KeyMany keys
SIS Benefits:
Standardized locks. Easy to manage and to maintain
SIS Benefits:
Reliable, flexible, easy to use. For stations of any voltage levels and bus types and setups.
30+ years of SIS development and application
Mr Jin Shuqiang pioneered the SIS technology in 1987. Since then, Unitech Zhuhai and other companies in China continue to research and innovate in the area of safe switching technology.
SIS Deployment in China
Over 22,00 sites with SIS in 2005
SIS Deployment in China (cont.)
The number of switching error related incidents dropped significantly
Interlocking Applications
Three Gorge Project
Shanghai World Expo 500 kV Substation
1000kV Substation
Conclusion
• Smart Interlocking System (SIS) is proven reliable technology that prevents switching errors.
• SIS has significantly reduced accidents and losses related caused by human errors in China.
• We look forward to deploying SIS technology to customers in the United States and other parts of world.
Q&A
Questions??
LOGOSafety Through Prevention –
Safe Switching Using Smart Key Technology
Shuqiang Jin, Unitech, Zhuhai, China Nan Liu
Youru Huang, SERCC
EPRI's 14th Annual Power Switching Safety & Reliability Conference San Diego, California September 20~21, 2010
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