Transcript Advances in Protection

System Protection
FECA 2012 Engineering Conference
Doug Freemyer, P.E.
Power Connections
• What are we protecting?
• Why are we protecting?
• Who are we protecting?
• Sensitivity
• Selectivity
• Speed
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BF
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BF
Proven Alpha Plane Principle
lm(k)
Internal faults
RESTRAIN
OPERATE
Synchronization
errors
CT saturation
Re(k)
–1
Internal faults
V
I
Fault
Z
Relay
V
I
X
Line Impedance
ZLOAD
ZFAULT
R
Zone 4
Zone 2
Zone 1
Zone 3
(Reversed)
Zone 5
(Reversed)
Positive
Sequence
Line Angle
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Bus Differential
Thermal
Over/Under Frequency
Over/Under Voltage
Etc.
• Security
• Stability
• Safety
• Speech (communications)
• Stuff (asset management)
• Regulatory requirements
• Smart Grid
• System Protection (thermal monitoring, alarming and trip)
1. Know all communications paths to your assets. Make sure
to include paths that are accessible locally, such as a thumb
drive. Draw a picture!
2. Use and manage strong passwords.
3. Secure communications with encryption and authentication
tools.
4. Practice a “need-to-know” policy, compartmentalize
knowledge—even guard your access tools.
5. For key assets, have more than one (secure!)
communications path.
6. Take action now. Don’t wait for a government mandate or
for an attack.
7. Review log files on firewalls, alarms, and access activity.
8. Don’t forget physical security.
9. Practice “security in depth.”
10. Have an incident response plan ready ahead of time.
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Automation
• Communications assisted schemes
• Synchrophasors
• Volt/VAR Control
• Asset Management
• Advances in Protective Devices
• Solid-dielectric insulation
• Magnetic Actuators
• Detect and automatically respond to multiple, consecutive
system contingencies.
• Control thousands of contingencies and loads with high-speed
communications.
• Preserve system stability using intelligent, contingency-based
actions, such as flexible load and generation shedding. All
loads/generation are prioritized and shed only when necessary
to satisfy the contingency.
• Detect unstable power conditions and automatically take
corrective action, such as system islanding, to avoid blackouts.
• Intelligent controls
• Single-phase tripping
Single-Phase Tripping Recloser
Single-Phase
Load
Fault
Single-Phase
Load
Single-Phase
Load
SEL-651R
Control Cable
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
Surface
Fault Impedance
Dry asphalt
Concrete (nonreinforced)
>1000 ohms
> 1000 ohms
Dry sand
Wet sand
Wet asphalt
>1000 ohms
500
>1000 ohms
Dry sod
Dry grass
Wet sod
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305
191
Wet grass
Concrete (reinforced)
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102
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Arc impedance
Ground-surface impedance
Earth-return impedance
Ground-surface and conductor-interface
impedance
Amperes
Impact of Fault Impedance
12000
10000
8000
6000
4000
2000
0
0 ohms
2 ohms
10 ohms
40 ohms
0
2
4
6
Miles
8
10
Locate downed conductors
 Alarm or trip for fault events below traditional relay pickup
 Operate securely to prevent false trips
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Automation
• Distributed Control
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Low-bandwidth requirement
Fast and secure communications
Improved fault location
Better reliability through design simplicity
High-speed, peer-to-peer system
• Centralized Control
• Avoid overload conditions
• Equipment ratings
• Conductor sizes
• Preserve protection coordination
• Feeder breaker relays
• Recloser controls
• Keep personnel safe
• Hot-line tags
• Control permission
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Automation
• Communications assisted schemes
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SONET
Serial Hardwire
Serial Fiber-Optics
Serial Radio
Ethernet Hardwire
Ethernet Fiber-Optic
Ethernet Radio
• Spread spectrum
• 802.11
• Bluetooth
Source
Midpoint
Source
A
B
SEL-651R
SEL-651R
SEL-651R
C
Fault Current
D
E
F
Source
SEL-651R
SEL-651R
Source
Midpoint
Tie
Source
Midpoint
Source
B
C
SEL-651R
SEL-651R
1 Trip Sequence
and Lockout
D
2
Sense Loss
of Voltage
E
SEL-651R
A
F
Source
SEL-651R
SEL-651R
Source
Midpoint
Tie
Source
Midpoint
Source
B
SEL-651R
C
SEL-651R
3 MIRRORED BITS
Communications
D
E
SEL-651R
A
F
Source
SEL-651R
SEL-651R
Source
Midpoint
Tie
Source
Midpoint
Source
B
SEL-651R
C
SEL-651R
SEL-651R
A
4 Open to
Isolate
the Fault
D
E
F
Source
SEL-651R
SEL-651R
Source
Midpoint
Tie
Source
Midpoint
Source
B
SEL-651R
C
SEL-651R
6 Fault
Isolated
7 Zone C
Powered
5 Close Tie
Recloser
D
E
SEL-651R
A
F
Source
SEL-651R
SEL-651R
Source
Midpoint
Tie
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Automation
• Communications assisted schemes
• Synchrophasors
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Find component or wiring defects
Increase situational awareness
Improve optimization of Volt / VAR control
Reduce losses due to loop flows
Speed up event analysis
Improve interconnection of distributed
generation (DG)
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Communications assisted schemes
• Automation
• Synchrophasors
• Volt/VAR Control – Power Quality
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Load tap changer (LTC)
Voltage regulator (VR)
Capacitor control
Distributed Network Automation (DNA) Solution
A: Load tap changers
B: Voltage regulators
C: Switched capacitors
D: All of the above
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Communications assisted schemes
• Automation
• Synchrophasors
• Volt/VAR Control
• Asset Management
• Transformer monitoring
• Thermal monitoring
• Through-fault monitoring
• Circuit Breaker & Recloser Monitoring
• Through-fault monitoring
• Contact wear monitoring
• Operations counter
• Compressor motor run time
• Trip Coil monitoring
• Intelligent controls
• Single-phase tripping
• Downed conductor detection
• Automation
• Communications assisted schemes
• Synchrophasors
• Volt/VAR Control
• Asset Management
• Advances in Protective Devices
• Solid-dielectric insulation
• Magnetic Actuators
• Ensuring that we are accomplishing our system protection
objectives.
• Regulator Compliance
• The more complex the system, the more complex and difficult
the testing.
The lines are blurring between traditional system protection,
automation, communications and power quality.
• What are we protecting?
• Why are we protecting?
• Who are we protecting?