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Modeling of Ontario Special Protection Systems

in Contingency Analysis

Yinhua Guo, Vivian Cheuk

Ontario Grid Control Centre

Hydro One Networks • Transmission Company in Ontario

– 98% of Ontario transmission system, 30,000km HV circuits

– Interconnect with New York, Michigan, Minnesota, Manitoba, and Quebec (asynchronous)

• Largest Distribution Utility in Ontario

– 123,000km low voltage distribution lines

– Serving 1.4 million suburban/rural customers

– Extensive distributed generation (wind & solar)

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Ontario Power Grid

Hydro One Networks 800,000 km2 Service Area

SPS Deployment in Ontario

• Over 50 SPS Systems in Operation

– Defend system stability, thermal & voltage limits

• Over 540 SPS Modules

– Over 720 contingency signals & over 3000 logic evaluations

• Over 470 Remedial Control Actions

• Secure Arming Logic

– Multi-level blocking switches & selection switches

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SPS Contingency Detection

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SPS Simulation- Contingency Detection

• Signal Types

– Status based

– Protective relay trip signals

– Analog value based (e.g., load shedding)

• Contingency Condition Derivations

– Over 720 SPS contingencies

– Over 3000 logic evaluations

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SPS Simulation- Control Actions

• Generation Rejection

• Load Rejection

• Generation/HVDC Runback

• Capacitor/Reactor Switching

• Breaker Trip/Close

• Group (generation, load, CB) Rejection

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SPS Simulation- Arming Logic • Selection & Blocking Switches

– Detailed logic for conditional arming status

• Staged Tripping

– Time staged control actions

– Violation level staged control actions

• Trip Supervision/Interlocking (analog, status)

– Local switch/relay to block GR if generation < threshold

– Load rejection: if Vpresent < V < Vthreshold

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SPS Arming Control - RC & TO

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Other Protections Modeled as SPS

• Over Load Protection

– Transformer 2pu protection

• Under Voltage Load Shedding

– Lower voltage threshold & voltage presence check

• Under/Over Voltage Capacitor/Reactor Switching

• Line-end Open

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Transformer 2pu Protection

– Staged tripping of loads in 4.5”, 7.5”, 9.5”

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– Over current based: I > 2*I_rated

RTNET & RTCA Sequence • RTNET every 30 sec

– State estimator

– Thermal limit calculation

– SPS base update

• RTCA every 3 min

– About 4400 contingency cases

– CA redefinitions

– Screening/full processing

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SPS & CA Redefinition

• Dynamically Expand CA Outages at CB Level

• Simulate Protective Relay Actions

– Interlock bypass switches considered

• Transfer Trip for LEO Protection

• SPS Remedial Actions Incorporated

• Cascading Outages: iterative simulation of interactions among SPS, LEO, overload, 59/27 voltage relays

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CA Redefinition

- Example of interlock bypassing & cascading

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SPS Results in CA

• For each SPS Module

– Total generation rejection selected

– Total load rejection selected

• For each Contingency Case

– SPS modules activated

– SPS control action equipment outages

– SPS control action CB tripped

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CA/SPS Results Validation

• Verification of SPS Simulation

– Simulated vs. expected results

– Simulated results against real events

• Verification of CA Solutions

– SE solution against SCADA measured values

– CA solution against SE/power flow solution

– Pre-outage CA solution against post-outage system state (real time or DTS Replay)

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Challenges & Experience

• Interactions of Different Control Actions

– Load rejection vs capacitor auto-switching

– Granularity of time stages

• CA Convergence vs SPS Actions

– Powerflow may diverge before load rejection, but analog based overload/undervoltage LR needs solved solution

• SPS Simulation Performance

– Code optimization

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Questions?

Contact: Yinhua.Guo@HydroOne.com

Ontario Grid Control Centre

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Thank You!