Transcript Phase Angle Alarming VR Energy JSIS 3-4-2015

Phase Angle Alarming in ROSE for
Steady-State Stability Analysis
Marianna Vaiman
V&R Energy
JSIS Meeting
Salt Lake City, UT
March 5, 2015
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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V&R’s Approaches to Phase Angle Limit
Computation
Phase angle limit should be determined in real time, and not based
on historical data
Phase angle limit is a physical limit:
– Depends on system topology and conditions;
– Depends on how the system is stressed;
– The limit changes with system conditions.
Voltage and thermal limits are operating limits:
– Depend on the equipment/hardware.
Three types of different phase angle limits:
– 1. Based on user-defined scenario-based stressing;
– 2. Based on optimal scenario-based stressing;
– 3. Based on “natural” direction of system stressing.
Phase angle limit can be computed using different data sets:
– State Estimator data; combination of State Estimator and PMU data; PMU data
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Approach 1. User-Defined
Scenario-based Stressing
Approach 1. User-defined sources/sinks:
– “Traditional”, but not optimal (maximum stressing)
Maximum transfer capability may be reached due to exhausting resources before
reaching voltage/thermal/stead-state stability violation.
POM computes the most critical (sensitive) phase angle differences
to each stressing:
– Both in real-time and off-line.
In addition, can monitor user-defined phase angle differences.
Phase angle limit is computed based on State Estimator (SE) data.
Alarming is done based on both SE and PMU data.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Computing Limits and Alarming in ROSE
The key computation in ROSE:
– ROSE computes both the limit and the current state, and
can issue an alarm based on these two parameters;
– Since the limits are computed in real-time, these limits
are “dynamic” (changing).
There are two types of alarms in ROSE:
– SE-based (model-based) alarming;
– PMU-based alarming.
Both types of alarms may be expressed in terms of
MW on the interfaces or phase angles.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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SE-Based Alarming
Two types of alarming are available:
– Flow on the interface in MW;
– Phase angle difference between two PMU locations in Degrees:
PMU locations are user-defined as an input.
Limit is computed both in MW and degrees.
If the difference between the limit in MW and base case
MW flow is less than MW alarming threshold, a MW alarm
is issued.
If the difference between the limit in degrees and base
case phase angle difference in degrees is less than Phase
Angle alarming threshold, a Phase Angle alarm is issued.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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PMU-Based Alarming
Two types of alarming are available:
– Flow on the interface in MW;
– Phase angle difference between two PMU locations in Degrees:
PMU locations are user-defined as an input
Limit is computed both in MW and degrees.
If the difference between the limit in MW and the current
MW flow obtained from PMU data is less than MW
alarming threshold, a MW alarm is issued.
If the difference between the limit in degrees and current
phase angle difference obtained from the PMU stream in
degrees is less than Phase Angle alarming threshold, a
Phase Angle alarm is issued.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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ROSE Analysis
Both 1-D or 2-D ROSE boundaries are computed;
– Each point on the boundary corresponds to thermal
overload, flowgate constraint, voltage violation, or
voltage collapse.
Alarms are issued for 1-D scenarios:
– Visualization includes trending of results in Real Time
and Historical Trend.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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ROSE Client at ISO NE
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2-D Limits in MW and Degrees
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Approach 2. Optimal Scenario-based
Stressing
Approach 2. Optimal sources/sinks determine by the software:
– Such that interface/path flow is maximized;
– Can be a pre-selected list of potential source/sink locations (such as several
control areas);
– This is maximum phase angle limit for the given interface/path.
POM computes the most critical (sensitive) phase angle differences to each
path/interface:
– Both in real-time and off-line.
– In addition, can monitor user-defined phase angle differences.
Phase angle limit is computed based on State Estimator (SE) data.
Alarming is done based on both SE and PMU data.
V&R has a planning tool to determine maximum interface flow and phase angle
limit.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Approach 3. “Natural” Direction of
Stressing
PMU data is used to determine the “natural” direction of
stressing.
Phase angle limit is computed based on both SE and PMU
data:
– PMU data is used to determine the change in system conditions,
and thus direction in which the system is stressed;
– SE data is used to determine the limit for the “natural” stressing
direction;
– Stressing in the traditional sense is not performed.
– This is not a commercial tool yet:
Technology/algorithms have been developed.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Only PMU-Based Analysis
Phase angle limit is computed based on PMU data.
PMU data is used to:
– Create a measurement-based real-time case;
– Determine phase angle limit using stressing.
Two ways to use measurement-based real-time case:
– Run the analysis when State Estimator (SE) case is not available or
the system approaches stability limits between the two SE cases.
– Run the analysis continuously without interruption all the time:
Case is created and computations are performed with approx. the sampling
PMU rate;
Stressing can be performed using any of the three approaches described in
the previous slides.
– This is not a commercial tool yet:
Technology/algorithms have been developed.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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Conclusion
V&R has developed different approaches to compute
phase angle limits.
Different types of phase angle limit computation are
discussed.
Computations are based on SE and PMU data.
Copyright © 1997-2015 V&R Energy Systems Research, Inc. All rights reserved.
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