secure power in high renewable penetration environment

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UCI Power Electronics Lab

1

Secure Power in High Renewable Penetration

Environment

Keyue Smedley1

Collaborators: Greg Smedley2, Taotao Jin2, Tong Chen2 , and Anto Joseph1

University of California Irvine 2. One-Cycle Control, Inc. Irvine

July 20, 2021

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2US Power Generation

2020:• 4,009,000 GWh• 60% Fossil• 20% Nuclear • 20% Renewables

(including hydroelectric)

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3US Renewable Generation

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4Renewable Challenges

Source: http://www.megawattsf.com/gridstorage/gridstorage.htm

• Intermittency• Fast Transient

• Voltage instability • Voltage regulation equipment

wear out prematurely • Black out, brown out

Source: One-Cycle Control, Inc.

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5VAR Stabilizes Power Grid

By extending the margin before voltage collapsing

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7Power Electronics--enabling high penetration

• Silicon has revolutionized IT. It is time to modernize our power system1.

• 4-quadrant power converter2,3

=> universal grid control actuator

• Fast precise control=> local autonomous reflexes

STATCON

PFCRectifier

oP

Q

ac/dcdc/ac

+VAR

-VAR

Inverter-VAR

Inverter+VAR

Inverter

STATCON

o

Q

ac/dcdc/ac

+VAR

-VAR

PFC+VAR

Inverter-VAR

Inverter+VAR

PFC-VAR

1. Keyue Smedley, “One-Cycle Control and Its Applications in Distributed Generation” COBEP 2004, Brazil.

2. K. Smedley and C. Qiao, Unified Constant-frequency Integration Control of Three-Phase Rectifiers, Inverters, and Active Power Filters for Unity Power Factor, US Patent filed 9/99, 6297980. 2001.

3. Taotao Jin and Keyue Smedley, “T. Jin, L. Li, and K. Smedley, Universal OCC Converter for Distributed Generation, Power Electronics Technology Conference, Chicago, 2004.

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1/Ts ∫0t V2dt=V1t=dTs

V2d=V1

• OCC solves the first order polynomial equation

• OCC solves most power electronic problems

One-Cycle Control Concept

Comparator

Integrator

Q QS R

clock

d

v1 v2

reset

with reset

CLK

v (t)+

v (t)1

Q

K. Smedley “control art of switching converters” Caltech Ph.D.Thesis, 1991

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10

OCC-DVC--Smart Grid Building Blocks

High efficiencyFast responseSmall footprint

Source: One-Cycle Control, Inc.

±60kVAR

+Q to -Q Q ramps up/down

±360kVAR

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11OCC-DVC--stabilize voltage

Source: of One-Cycle Control, Inc.

Set point

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12SDGE Installation

OCC-DVC ––Quench the transientRegulate the voltage to a flat line

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13OCC-DVC (Voltage Schedule)OCC-DVC = OFF OCC-DVC = ON

OCC-DVC OFF: wide voltage fluctuation OCC-DVC ON: voltage is scheduled

OCC-DVC ON: VAR injection

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15OCC-DVC (Dynamic Load&PV)

OCC-DVC ON: Voltage is a flat line

OCC-DVC ON: VAR injection

2 load drops èSolar power surges back to transformer

Voltage is stabilized

OCC-DVC fast actionTo combat the transient

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16

October 18, 2013, 9:03AM• 500kV line fault • Voltage sag was detected in every substation• Except the one with OCC-DVC ON

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17Duke Energy Installation

Source: Duke Energy

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18

140 bus SCE DPS simulation of coordination of Fast VAR

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No reactive injection With reactive injectionFrequent transient activities Smoother operation

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28

• Synchronous condenser: high inertial not suitable for fast transient intermittency

• Switching capacitor and LTC: slow speed and step control• SVC: too slow to capture the fast transient of renewables• STATCON: may be able to handle when the transient is

mild • OCC-DVC has demonstrated fast transient suppressing

capability • Opportunity: OCC-DVC coordination with LTC, Switching

Cap, and SVC è smooth and cost-effective solutions.

VAR & Voltage RegulationMethod Comparison

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29OCC-DVCEnables high penetration

secure power in high renewable penetration environment

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