Scott Bonnett – Candidate

A Power Quality Case Study Simulation

By

Scott Bonnett

Scott Bonnett – Candidate 1

Purpose & Content of This Presentation

Purpose • To confirm my interest in the position of Project Engineer - PSS (224) • To demonstrate that this kind of analysis is within my capability • To provide a basis for further discussions with S&C

Content • Simulation of a power quality case study previously reported by E. Camm (et. al.)

• Capacitor switching at main grid caused nuisance overvoltage trips at customer • Pre-insertion inductors identified as a way to fix the problem • Details in Reference 1

• Simulation performed by Scott Bonnett using Matlab / Simulink simulation tool • Model configured & parameterized according to information in Reference 1

• Not all component parameters were known, some were tuned to match paper • Some were set to values found in Mathworks power system example models

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Simulation Desktop

Parameters Model Block Diagram Plotting Area

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Model Components

100kV Source

600kvar Cap

Customer Load

Transformer (100kV->12.47kV)

Transformer (12.47kV->480V)

900kvar Cap

450kvar Cap

Substation Load

Transmission Lines

Pre-Insertion Inductor

57.6Mvar Cap

Breaker

Scott Bonnett – Candidate

Without Pre-Insertion Inductor With Pre-Insertion Inductor

Simulation Results

4

100kV Bus (volts)

480V Bus (volts)

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Model Parameters

5

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Additional Analysis - Disturbance Response

• Model configured such that a disturbance can be overlaid on the 100kV source • Transfer function input is disturbance signal from the 100kV source • Transfer function output is the voltage at the 480V customer site • Transfer function analysis used to determine contributions due to separate factors • Analysis cases (see next slide)

• No capacitors, transmission lines only • No transmission lines, capacitors only • Both transmission lines and capacitors present

Transfer Function Input Transfer Function Output

Input Output

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Disturbance Response Plot

This plot shows that although some frequency separation exists between transmission line and capacitor bank resonances, the two will still couple dynamically.

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Summary & Discussion

Summary • Solution that was found to work in original paper was confirmed in this simulation

• Pre-insertion inductors upstream of 100kV cap bank Discussion • System modeling, simulation, and controls analysis has been part of my day to day

work for over 20 years • In the references I also read about S&C’s work with reactive compensators and PWM

based voltage controls • I have simulated both in the context of aircraft power systems in the past

• Financial feasibility calculations were not part of this presentation, however: • I earned an MS in Finance at IIT, which included net present value calculations

• Perhaps adaptive control techniques have application in power system controls? • My MS thesis focused on system identification and adaptive speed control of a

hydropower turbine

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References

1. Main: “Solving Customer Power Quality Problems Due To Voltage Magnification”,

R.A. Adams, S.W. Middlekauff, E.H. Camm, J.A. McGee, PE-384-PWRD-0-11-1997, IEEE / PES Winter Meeting, 1998.

2. “Preventing Overvoltage Tripping of Adjustable Speed Drives”, E.H. Camm, Plant Engineering, S&C edoc_001584, February 2004.

3. “Evaluating Advanced VAR Compensators for Improved Power System Stability”, E.H. Camm, S&C edoc_027268, October, 2004.

4. “Design Considerations For Large Collector Systems”, E. Camm, North American Wind Power, S&C edoc_045122, December 2006.

5. “Shunt Capacitor Overvoltages and a Reduction Technique”, E.H. Camm, S&C edoc_024494, April 1999.

6. “Current Limiting Inductors Used in Capacitor Bank Applications and Their Impact on Fault Current Interruption”, T.A. Bellei, E.H. Camm, G. Ransom, S&C edoc_002794.

7. “Dynamic Reactive Power Control for Wind Power Plants”, E.Camm, C. Edwards, K. Mattern, S. Williams, Techwindgrid 2009 Grid Integration Seminar.

8. “Substation Capacitor Bank Switching & Protection Design Considerations”, E.H. Camm, S&C Electric Company, June 2014.

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Thank You

Thank you for your time! I would be glad to discuss the position further at S&C’s convenience. Scott Bonnett 815-262-8712 scobro59@gmail.com