Research at the Renewable Energy Systems Laboratory (LaSER)

Computational tools for thedesign and evaluation of

electrical systems with PV generation

Miguel TorresPostdoctoral Researcher

Contact:

Miguel Torres L., PhDPostdoctoral FellowSolar Energy Research Center (SERC-Chile)Department of Electrical EngineeringUniversity of ConcepcionEdmundo Larenas 219Concepción, ChilePhone: +56-41-2203649Skype: migueltorres.clGmail: miketangoLinkedin: www.linkedin.com/in/mtorresl

Outline

• Introduction

• Integration of NCRE into power systems

•Available resources

•Hardware-in-the-loop application example

Introduction

Motivation

• Large-scale NCRE plants are already beingconnected to the Chilean national grid (SIC and SING).

•Example: PV plant Llano de Llampos 100 MW.

PV plant Llano de Llampos (connected to SIC)Chile – Copiapó

PV plant Llano de Llampos (connected to SIC)Chile – Copiapó

• Located at 1150 m of altitude

• Area of 280 acres• 314 640 panels• 325 Wp/panel• Capacity of 100 MWp• Connected to SIC on

Feb. 16 2014 (220 kV)• 92 MWp effective• Silent operation• 1-axis tracking system• Manual cleaning

View of the real plant

Converter stations 360 – 23 kV

• 3 conv per secondary• Each converter of 250 kW• Total of 250x6 = 1,5 MW

per station• It does MPPT

Challenges of the integrationof large-scale NCRE plants to power systems

Planning:

• Inter-hour variation of generated power (hardto estimate).

•Uncertainty in generated power.

• Large variations in generated power.

Operation:

•No contribution of inertial power (PFC).

• Low contribution under voltaje sag.

Variations in power generated by Llano de Llampos PV plant

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

10.0

60.4

73.674.773.673.173.574.274.9

69.0

35.1

0.4 0.0 0.0 0.0 0.00.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

PO

TEN

CIA

[M

W]

Despacho Diario Cental Solar PV Llano de Llampos - SIC

Stability in power systems

Angle Frequency Voltage

Stability

Inertial response and PFC

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Available resources

Applied Digital Control Laboratory (LCDA)

•More than 10 years of experience• Students of different levels: PhD, Master and

undergrads• Control of electronic power converters• Study of new conversión topologies• PCB design• Solar energy applications

Electric Supply Quality Laboratory (LCSE)

•More than 10 years of experience• Students of different levels: PhD, Master and

undergrads• Research on power systems and power quality• Collaboration with the regional industry• Extensive use of Digsilent, Power analyzers and

power monitors.

Renewable Energy Systems Laboratory(LaSER)

•New facilities (96 m2)• Fondequip project: 230M CLP

• Real-Time simulator• SERC internal fund: 50M CLP

• PV emulators• Power amplifier 15kW

•Other funds: 15M CLP• Infrastructure

PV emulators (3 units)

• 2.6 kW• 600 V/4.3 A• Multiple PV profile

Example: Grid-tie PV inverter(Master thesis, Gustavo Hunter, University of Concepcion)

OPAL-RT Real-Time simulator

OPAL-RT system modes of operation

• SIL• Fully digital simulation.• No sinchronization with real world.• Accelerates testing phase.

• RCP• Control system design.• Simulator controls actual plant.• Allows flexibility in design and debugging

phase.

• HIL• Controler under test is connected to

simulated plant.• Flexibility in testing the control unit.• Testing of extreme events.

• PHIL• Simulator connected to power amplifier.• Testing of power equipments.

Triphase power amplifier

Electrical gridemulation

Modular powerconverter

Emu. PV

Power amplifier

PV plant

Control board

+Sensors

Emu. PV

Emu. PV

Controlboard

HIL PHIL

Setup

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Example:Hardware-In-the-LoopVirtual Synchronous Machine (VSM): adding inertia to PV plants.

Background

• Frequency deviations are first limited by inertia and then by PFC units.

• PV plants are non-rotating generators that add no inertia to the system Loss of inertia, frequency control and stability.

• VSM allows a PV plant to support PFC units by emulating inertial response and primary mover.

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VSM concept

* Image obtained from “Potentialities of the Virtual Synchronous Machine(VISMA) to improve the quality of the electrical grid”

SSG (FACTS Terms & Def. Task Force IEEE, 1997)

VSM, VSG, VSYNCH, SYNCHRONVERTER, MSV

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VSM for dynamic frequency control

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Inertial response Damping power

0.96

0.97

0.98

0.99

Time (s)

0.5 1 1.5 2.5 3

1 kg∙m2

Variable inertia 3 kg∙m2

Electrical grid emulation

Control boardVSM

algorithm

f

Experimental setup

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df

dt

f