2. EDUCATION:
Master of Science - Michigan Technological University
Department- Electrical & Computer Engineering
Internship:
Manager- Jay R. Dondeti
Mentor - Charles
Department- EMS Engineering
3. OVERVIEW
Roles of EMS Engineer
EMS Applications
Significance of Mvar
Project: Mvar State Estimator Solution Improvement
• Tasks Accomplished
• Voltage/Var Performance
• XF Tap Change Case Study
• Tap Estimation
Concerns
Future Work
Suggestions & Questions
3
4. ROLES OF EMS ENGINEERING
4
Maintain/operate State Estimator and Real Time
Contingency Analysis applications
24*7 monitoring and resolving solution issues
Model Issues
Resolve Application Issues: Working with other
teams in MISO and vendor (ALSTOM)
Application Enhancement
5. EMS APPLICATIONS
SCADA
State Estimator
(SE)
Real-time
Contingency
Analysis (RTCA)
Loss Sensitivity
Calculator
(LOSSES)
Constraint Activity
Logger
(CLOGGER)
Unit Dispatch
System (UDS)
Unit Output
Breaker Status
Loss sensitivities
Constraint list and
sensitivities
Constraint list and
sensitivities
Analogs
Statuses
Real-time Model
Automatic
Generation Control
(AGC)
Island
5
Network Topology
6. 6
APPARENT POWER
Beer: Full glass
Electricity: Available from
utility
REACTIVE POWER
(MVAR)
Beer: Foam
Electricity: Unable to do
work
REAL POWER (MW)
Beer: Drinkable
Electricity: Able to do work
It is the Active Power that contributes to the energy consumed, or
transmitted. Reactive Power does not contribute to the energy. It
is an inherent part of the ‘‘total power’’ which is often referred as
“Useless Power”.
SIGNIFICANCE OF Mvar
7. 7
Benefits
Improves system power
factor
Reduces network losses
Avoid penalty charges from
utilities for excessive
consumption of reactive
power
Reduces cost and
generates higher revenue
for the customer
Increases system capacity
and saves cost on new
installations
Improves voltage
regulation in the network
Increases power availability
9. 9
Tasks Accomplished
1
• Analyzing the data and getting a statistics of
tap positions of the transformers for each of
the companies/ areas
2
• Evaluating the performance measurement for
various cases
3
• Analyzing the transformers having the highest
residuals and thus contributing to a high PM
4
• Analyzing effect of tap estimation in
Performance measurement
10. 10
5
• Highlighting the areas of concerns, issues
such as model issues, measurement issues
etc.
6
• Automated the process by writing few
jython scripts so that can be reused in
future
7
• Provided valid data points with charts, bar
graphs and excel documents, so that can
be shared with concerned teams to take
necessary actions for the concerned areas
Tasks Accomplished
13. AECI
13
Base Case: Tap is already at nominal 0 (min=-16 and max=16) Residuals = 45.94
All nom case: Tap is already at nominal 0 (min=-16 and max=16) Residuals = 45.94
18. LES
18
All Nom Case: Tap is 7(XF is on tap estimation) Residuals = 97.91
Tap is set to 0(nominal) PM=33.28 Residuals = 21.37
19. EES
19
Base Case: Tap is 3(min=-1; nom=3; max=5) Residuals = 67.32
Only min to nom Case : Tap is 3 Residuals = 67.20
20. EES
20
All nom Case : Tap is 3 Residuals = 29.08
Flipped the sign Residuals = 19.57
PM doesn’t improve!!!
21. 21
NELSON_E (T1)
Base Case : Tap is 3(nom=3;min=1;max=5) Residuals = 38.77
Only min to nom Case: Tap is 3(nom=3;min=1;max=5) Residuals = 29.32
22. EES
22
All nom Case: Tap is 3(nom=3;min=1;max=5) Residuals = 87.66
RBEHV (AT1_500): Residual shoots upto 74.54 from 41.24 for all nominal case
23. TAP ESTIMATION: ONT
23
Base Case: Tap is 2(nom=11;min=1;max=21) Residuals = 360.97
All nom Case: Tap is 2(nom=11;min=1;max=21) Residuals = 93.91
24. TAP ESTIMATION: ONT
24
All nom Case: Tap is 9(nom=11;min=1;max=21) Residuals = 26.50
Flag is checked for Tap Estimation
25. TAP ESTIMATION: TVA
25
Base Case: Tap is 15(nom=12;min=1;max=23) Residuals = 218.26
All nom Case: Tap is 15(nom=12;min=1;max=23) Residuals = 229.57
34. 34
High no. of
Observable Taps:
Better PM with
Tap Estimation
Low no. of
Observable Taps:
Worse PM with
Tap Estimation
High no. of
Observable Taps:
Worse PM with
Tap Estimation
Low no. of
Observable Taps:
Better PM with
Tap Estimation
35. Concerns
35
Model Issues:
• Nominal tap is not set to proper value
• No taps assigned
Measurement Issues: Flipped measurements
Tap estimation: Low observability
36. 36
Future Work
Sharing the data with modelling team and
discussing about action points
Implementing the suggested changes to
get a better Mvar Solution
37. Learned How the EMS System works
Implementation of Theoretical Ideas
Exposure to Alstom EMS
Automated the process for future use
Improvement of analytical and coding
skills
Made new friends
37
SUMMARY
MISO as market operator, RC, and BA
Monitors the transmission system to ensure flows and voltages remain within limits
Balances injections and withdrawals, manage congestion, and produce prices
To achieve this we need to know the current topology, state, and flows, and potential constraints on the power system
EMS Eng provides the necessary services
Energy Management Systems (EMS) are used to monitor (Alarm, SCADA, SE), analyze various impacts (CA, NETSENS), and control (AGC)
EMS is a traditional, but critical and complex, piece in system operations
Maintain/operate State Estimator and Real Time Contingency Analysis applications to ensure high quality, availability of solutions
Monitor and resolve solution issues on a continuous basis (RT 24x7 desk) within performance criteria
Work with modeling team to resolve model issues
Ensure new models are tested and tuned before propagating to production
Resolve application issues by debugging complex software and data issues, testing patches and releases, and working with teams at MISO and vendor (ALSTOM)
Design and develop new applications and tools, and work with vendor to design and enhance applications
Increasing var load reduces the ability of the system to deliver real power and perform useful work. In extreme cases, a high var load can shift the voltage and current so much that it reduces the power system’s delivery capability so that almost no active power can be delivered. There can also be other undesirable effects like low voltages and increased equipment heating and system losses.
While reactive power does not provide useful work, it is essential for AC transmission and distribution systems, motors, and many other types of customer loads. For motor loads, sufficient var levels are needed to avoid voltage sags that inhibit the conversion and flow of watts to meet load demand. Therefore, actual power systems require both real and reactive power to function properly.
[http://blogs.dnvgl.com/utilityofthefuture/reactive-power-what-it-is-why-it-is-important]
