Sustaining the grid of the futurewith SG3125HV-30

AIM AND SCOPE

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Through this webinar we will deep into the new features provided by the last generation Central Inverter SG3125HV-30, especially the ones focused on grid support.

General features of this central inverter will be shown, as well as available power block sizes and setup

General grid support features will be described, including the procedure for validating last generation grid support algorithms

DC coupling possibilities and applications will be introduced

Handover to Inaccess to show real onsite applications worldwide, making this central inverter + Power Plant Controller-Energy management system the key to success in the complex scenarios that will appear in a close future

SG3125HV: FEATURES & PLANT SETUP

INTRODUCTION

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SG3125HV-30 is the last generation of the widely used SG3125HV family 1500Vdc Central Inverter

Central Inverter technology has substantially been developed also over the last 5 -10 years.

• Lower cable loss

• Higher system efficiency

• Lower system cost

• Simpler system

• Lower system cost

• More stable grid control

Power density DC voltage increase

1MVA, Indoor, 1000Vdc 3,4MVA Outdoor, 1500Vdc

GENERAL FEATURES

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• 10% overloading up to 45ºC 3437kVA

• 2 MPPT per inverter

• IP65 Inverter

• Max. Efficiency 99%, Euro. efficiency 98.7%

• DC/AC ratio up to 1.8

• 24h online AC insulation monitoring

• Reactive power response time <30ms

• SCR≥1.2 stable operation in extremely weak grid

• Built-in ESS interface，support PCS operating mode

BLOCK LAYOUT

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Plug&Play Solution

Minimum Civil Works

Includes Auxiliary Transformer up to 30kVA

Outdoor concept (except RMU cubicle)

SG6250HV-MV All in one with 2xSG3125HV-30

SG3125HV-MV-30 solution with 1xSG3125HV-30

PLANT DESIGN

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POWER BLOCK 6,8MW

The perfect fit for

large utility and Floating PV

PLANT DESIGN

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SG6250HV-MVCombiner Box

PVS-24MH

iSolarCloud

Smart Control Unit

• All-in-one , highly integrated design

• Max. 48 inputs，DC/AC ratio up to 1.8

• 4 MPPT, independent operation

• PVS-24MH Combiner Box

• 24 inputs，positive & negative fuse

• SMC enclosure，C5 & IP67 protection

• Unified communication interface, easy

O&M

• Remote monitoring-iSolarCloud,

SG3125HV-30: GRID SUPPORT

RESPONSE TIME

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• Response time verified by 3rd party

• 30ms for Reactive power

• 140ms for Active Power

• Q at night function

• Easy compliance with EU631 (1-5s for Voltage Control)

Inverter integrated with fast power control module

110/220kV

＜30ms

60% Reactive capacity

WEAK GRID PERFORMANCE

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• Voltage Oscillation observed when SCR is extremely low

• Low SCR grid will be more frequent with high renewable

energy penetration

• Validation of these algorithms is only posible with the

right equipment

• SG3125HV-30 works in stable operation when SCR>1.2

HIL VALIDATION SETUP

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Analog & Digital I/O

PWM

RS485

TCP/IP

a. Host computer

b. Opal-RTreal-time simulator

d. HMI Screen

c. Inverter controller unit

e. PPC

Analogue interface IEC104

HIL MODELLING

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Adjustable grid

impedance to

simulate different

levels of SCR

Real-time adjustable grid SCR

HIL RESULTS

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No voltage oscillation overserved when SG3125HV-30 inverter operates at SCR=2 and X/R=3. Inverter is fully functional during both

normal operation (90% power output) and fault ( 90% power, three phase to ground, 95% voltage-dip) conditions. Experimental

waveforms are shown

Voltage, reactive current, active power and reactive power measured at POC during fault

Three phase Voltage at current at POC

DC COUPLING AND APPLICATIONS

MAIN APPLICATIONS- DC COUPLING.

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Clipping Recapture

Max. power of Inverter

Ramp Rate Control

Power curtailment

Curtailment Recapture

Control the rate of PV power plant, reduce the grid impact

Minimize the power clipping losses for high DC:AC ratio projects

Plant curtailment, energy time shifting

Charging the batteries Charging the batteries

Discharging the batteries Discharging the batteries

Power of PV power plant

MAIN APPLICATIONS- DC COUPLING.

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Key Features

Bi-Directional Inverter charging and discharging from the grid

No standalone PV/BESS combiner box required

Parallel up-to 3x DC/DC converters

Allows for 1:1 PV/BESS ratio

Each DC/DC contains up to 10x 125kW DC/DC converters

Stops the battery short circuit current at rack level

Futureproof (Add DC/DC + ESS in the future )

Grid

10-35kV

SG3125HV-MV-30

3.125MVA

PV Plant

Batteries SD1250HV

1.25MWdc 3.727MWh

SCENARIO 1. PV EXPORT+BATT CHARGE

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5MWp

1.25MWdc3.727MWh

Assumptions

⚫ The inverter track MPPT

⚫ EMS/Controller communicate with inverter and

DC/DC. The EMS/controller dispatch the

output.

Conditions

Irradiance = 1000W/m²

PAC* = 3.125MWac

SoC < 100% EMS/Local Controller

PPV

PAC1000W/m²

VDC

5MWp

3.125MW

+1,25MW

[Standard Working Model]

SCENARIO 2. NO PV EXPORT+BATT CHARGE FROM THE GRID

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5MWp

1.25MWdc3.727MWh

3.125MWac

Assumptions

⚫ No losses

⚫ Irradiance is proportional to IPV

⚫ PDC* and PAC* are EMS control values

Conditions

Irradiance = 0W/m²

PAC* = 1.25MWac

SoC > Lower Limit

PPV

PDC

PACVDC

+1.25MW

+1.25MW

EMS/Local Controller

PDC*

PAC*

0MWp

[Standard Working Model]

SCENARIO 3. MINIMAL PV EXPORT+ PRIORITY BATTERY CHARGING

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1.25MW

5MWp

1.25MWdc3.727MWh

3.125MWac

Assumptions

⚫ The inverter track MPPT

⚫ EMS/Controller communicate with inverter and

DC/DC. The EMS/controller dispatch the

output.

Conditions

Irradiance = 400W/m²

PAC* = 0.75MWac

SoC < 100%EMS/Local Controller

PPV

PDC

PAC400W/m²

VDC

2MWp

0.75MW

PDC*

PAC*

[Non Standard Working Model]

SCENARIO 4. NO PV EXPORT+BATTERY RECHARGING PRIORITY

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[Non Standard Working Model]

5MWp

1.25MWdc3.727MWh

3.125MWac

Assumptions

⚫ No losses

⚫ Irradiance is proportional to IPV

⚫ PDC* and PAC* are EMS control values

Conditions

Irradiance = 200W/m²

PAC* = 0 Mwac

SoC < 100%

PPV

PDC

PAC200W/m²

VDC

1MWp

0MWAC

1MW

EMS/Local Controller

PDC*

PAC*

SCENARIO 5. COMBINED PV EXPORT+BATTERY DISCHARGING

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[Non Standard Working Model]

EMS/Local Controller

5MWp

1.25MWdc3.727MWh

3.125MWac

Assumptions

⚫ No losses

⚫ Irradiance is proportional to IPV

⚫ PDC* and PAC* are EMS control values

Conditions

Irradiance = 400W/m²

PAC* = 3.125 Mwac

SoC < 100%

PPV

PDC

PAC400W/m²

VDC

PDC*

PAC*

2MWp

3.125MW

1.25MW

SUMMARY-DC COUPLING

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Subsidy Free Era

⚫ Wanting to go beyond the Standard PV designs

⚫ Negative price during the day

⚫ Emerging revenue streams

Network Quality Issues

⚫ Frequency & Voltage fluctuation

⚫ Over Capacity

⚫ Low Short Circuit Ratio

DC

Side

AC

Side

Lack of Grid Capacity

⚫ Increased connection cost

⚫ Saturated grid

⚫ Expensive infrastructure upgrades

⚫ Enhanced Grid support functionality –Reducing the need for grid reinforcement works

⚫ Exporting both PV and ESS -Maximizing the Grid Connection Agreement

⚫ Ramp rate control and Capacity Firming

⚫ De-risking energy loss during plant curtailment – Utilization of Storage

⚫ Overall efficiency of the solution is increased –Compared to a traditional AC co-located system

⚫ Global reduction on plant cost - Making DC/DC solution more viable

⚫ Export energy at peak revenue earning times –Maximizing the site potential

SG3125HV-MV-30 Plus SD1250HV

CONCLUSIONS

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DC

Side

AC

Side

Main factors that all PV inverters must have for the new era

Compact design and high power density, reducing the space needed for the inverter station and the installation time for a lower system cost

Advanced grid support features, validated in laboratory as much closer to reality as possible (HIL)

Compatibility with Energy Storage Systems, to implement all the requests that will be needed sooner than expected.

THANK YOU!