Renewable Integration (Solar PV) and Microgrid - IIT Kanpur

Sandeep Anand

Department of Electrical EngineeringI.I.T. Kanpur, India

Renewable Integration (Solar PV) and Microgrid

QIP COURSE ON SMART GRID TECHNOLOGIES

May 10, 2019

PERI Laboratory IIT KANPUR

Overview

2

1. Solar PV Scenario – India,

Worldwide

2. Issues and Challenges in String

Inverters• Leakage Current

• Efficiency

• Reliability

3. Upcoming Grid Standards • Smart Solar Inverter

4. Microgrids• DC Microgrids

• AC Microgrids

5. Other projects• Transformer Controlled Switching

• Reliability Evaluation: Battery Charger

• GaN based dc-dc converter

• Dynamic Voltage Regulator


Rising Electricity Demand

3

1 The World Bank: https://data.worldbank.org/indicator/EG.ELC.ACCS.ZS2 Energy Information Administration: https://www.eia.gov/todayinenergy/detail.php?id=32912

• About 12.6% of global population unelectrified

• Lots of these are electrified but get limited hours of supply

• Growing Industries• US-EIA projects 28% increase in world energy

use by 20402

• Electrification of Transport

0

1

2

3

4

5

6

7

8

India World

Population without electricity 1

1.32 Billion (15.5%)

7.6 Billion (12.6%)

1


Distributed Generation

4

• World average T&D losses: 8.26%

• Investments in Building Infrastructure

• Remote areas / Difficult terrain

• Move towards distributed generation

12014 World Bank Data: https://data.worldbank.org/indicator/EG.ELC.LOSS.ZS2CIA Data: https://www.cia.gov/library/publications/the-world-factbook/rankorder/2236rank.html

0

200

400

600

800

1000

1200

1400

1600

1800

USA Japan China India Kenya

Installed Capacity GW (% Loss)

1075 (6%)

313 (4%)

1646 (5%)

308 (19%)

2.2 (18%)

2


Shift Towards Clean Renewable Sources

5

1Sep 2017 CEA: http://www.cea.nic.in/reports/monthly/generation/2017/September/actual/actual.html2014: https://data.worldbank.org/indicator/EG.ELC.RNWX.ZS?year_high_desc=true2017, US: https://www.eia.gov/energyexplained/index.php?page=electricity_in_the_united_states

66%

14%

110010 84867 14101 75150

20000

40000

60000

80000

100000

120000

Total Thermal Large Hydro RES

Production (GWh) India Sep’17

77%

7%

0

10

20

30

40

50

60

70

Denmark Germany World

Electrical Energy From Renewables 2014 (%)

7%

3


Solar PV Potential

6

1http://solargis.com/assets/graphic/free-map/GHI/Solargis-World-GHI-solar-resource-map-en.png2 NISE, MNRE report: http://mnre.gov.in/file-manager/UserFiles/Statewise-Solar-Potential-NISE.pdf

• Low maintenance• Cost effective even for small

installations• No mechanical moving part –

long life• Reducing panel cost.

• $2 (2009) to about $0.3 (2017)

• Reducing LCOE (levelized cost of electricity)


Research Challenges in Solar PV Systems

7

Inverter Circuit

Controls

Grid

Solar plant level issues

Microgrids: AC and DC

Power Quality / Control

LVRT, Voltage Support

Cost, Volume – leakage currents

Efficiency – at low PV voltage

Reliability – online monitoring


Solar PV Inverters: Categories

8

Central Inverters String Inverters Micro Inverters

High Power, 100-500kW3-phTransformer basedFavourite topology: Conventional VSC

Medium Power, 3-20kW1-ph usuallyWith transformer and without transformer

Low Power, 50-500W1-phLow Voltage, High freq. isolation transformerSoft switching, unfolding circuit

Array level tracking String level tracking Panel level tracking(cost may be high)

https://www.ev-power.eu/Micro-Inverters-Tech/


Size and Cost: String Inverters

9

Low frequency transformer based« Conventional 2-level 1-ph VSC« For low PV voltage

- use transformer and VSC« Good efficiency, high cost, large weight

High frequency transformer based« Multi-stage power processing« Efficiency may reduce, due to multiple

stages« Cost does not necessarily come down

Without transformer / Transformer-less« Use dc-dc boost + VSC ?

https://link.springer.com/article/10.1007/s40565


Leakage Currents

10

⁞ Grounded metallic frame and structure⁞ Solar PV panel has considerable surface area

⁞ forms parasitic capacitance with the frame⁞ Typical values: Crystalline = 50 - 150nF/kW, Thin Film = 1uF/kW


Leakage Currents

11

⁞ Inverter operation, swithing frequency (Fs, 2Fs) voltage across parasitic C⁞ Capacitance is a high pass filter⁞ High frequency current flows through ground.⁞ Interfere with protection devices - ELCB (earth leakage), RCB(residual), RCD (residual

current detector), RCCB (residual current)

Leakage Current (mA)

Disconnection time (s)

30 0.3

60 0.15

100 0.04

VDE 0126-1-1


Voltage Across Cp

12

⁞ Unipolar PWM⁞ Higher efficiency, reduced filtering requirements⁞ High frequency parasitic voltage

⁞ Bipolar PWM⁞ No high frequency parasitic voltage

Switch States (ON) S1, S2 S3, S4 S4, S2 S1, S3

Vba 0 0 -Vdc/2 +Vdc/2

Vp1 𝑉

2−𝑉

2

𝑉

2−𝑉

2

𝑉

2

𝑉

2− 𝑉

Vp1

𝑉 +𝑉

2+ 𝐿

𝑑𝑖

𝑑𝑡−𝑉

2= 𝑉KVL through S1:

Vp1 𝑉 =𝑉

2−𝑉

2− 𝑉 H

J


Understanding in terms of common mode voltage

13

⁞ CM and DM components⁞ CM voltage is expressed as 𝑢𝑐𝑚 = (𝑢AN + 𝑢BN)/2

E. Gubia, P. Sanchis, A. Ursua, J. Lopez, and L. Marroyo, “Ground Currents in Single-phase Transformerless Photovoltaic Systems.” in Progress in Photovoltaics : Research and Applications., vol. 15, May 2007, pp. 629–650.


Solutions

14

⁞ Installing isolation transformer, close to inverter

⁞ No path for leakage currents⁞ Ground dc-link for safety

⁞ Also solves the low PV voltage issue

⁞ Modify inverter circuit topology⁞ H5, HERIC, clamped HERIC⁞ Cascade with dc-dc reduces efficiency

http://www.elsevier.es/en-revista-ingenieria-investigacion-tecnologia-104-articulo-high-efficiency-single-phase-transformer-less-inverter-S1405774315000037

H5



15

Inverter Circuit

Controls

Grid









Low Voltage

16

⁞ Solar PV voltage varies⁞ Variation in Junction Temperature: Temp. Coeff. of about 0.3%/oC,

variation of 50oC, 15% variation in PV voltage⁞ Partial Shading: 10 panels, (b) 50% shade 1-panel⁞ Degradation of panels


Solution: Current Source Inverter

17

Advantage: Single stage boost + inverter

Problem: High earth leakage current

Common mode voltage in conventional CSI


Proposed Solution

18

S. Anand, Saikrishna Kashyap and B.G. Fernandes, "Transformer-less Grid Feeding Current Source Inverter for Solar Photovoltaic System," IEEE Transactions on Industrial Electronics, vol. 61, no. 10, pp. 5334-5344, Oct. 2014

Current in zero state


Proposed Solution

19

High reliability. Increase cost, low power density 2011-2012

S. Anand, Saikrishna Kashyap and B.G. Fernandes, "Transformer-less Grid Feeding Current Source Inverter for Solar Photovoltaic System," IEEE Transactions on Industrial Electronics, vol. 61, no. 10, pp. 5334-5344, Oct. 2014


L vs C (AEC)

20

Value A / V Rating Cost Weight Volume

L 3.74mH 15A 2000 INR (30 USD) 2 KG (2.2lbs) 382 cm3

C 470uF 450V 730 INR (10 USD) 100 gms (0.22lbs) 43 cm3

Energy Wt (gm / J) Cost (INR / J) Vol (cm3 / J)

L 0.42 J 4762 4762 909

C 47 J 2.1 16 1


Solution: Partial power processing, VSI

21

⁞ Reduction in size⁞ Improvement in efficiency during boost stage⁞ High efficiency when boosting is not required


Circuit

22

HERIC mode

DC-DC + H5 mode


Modes of Operation

23


Selection of States: Common Mode Voltage

24

Leakage current vs. filtering requirements


Results

25

Experimental Results for (a) Five-level mode of operation (RMS value of leakage current: 16.2071 mA) (b) Three-level mode of operation (RMS value of leakage current: 12.9696 mA).[Inverter Voltage: 100 V/div, Grid Voltage: 100 V/div, Grid Current: 10 A/div, Leakage Current: 200 mA/div, Time: 5ms/div].


Experimental Setup

26


India Innovation Growth Program (IIGP)

27

University Challenge winners (top 3) of the DST -Lockheed Martin - Tata Trusts India InnovationGrowth Programme (IIGP) 2.0 for 2017

Maguluri Avinash, Anup Anurag, NachiketaDeshmukh, and S. Anand, "A Single Phase GridConnected Transformer-less Photovoltaicinverter", Indian Patent, Appl. No. 201611036171,2016



28

Inverter Circuit

Controls

Grid









Reliability of String Inverters

29

• High Ambient Temp• Temp oscillations• Limit the life of Inverters

• High warranty on solar PV modules (about 15-20 years)

• Inverter warranty about 5-10 years

1 http://completesolar.com/wp-content/uploads/2013/09/MicroString-1024x384.jpg


Failure and Maintenance

30

• Large maintenance cost

• Cost of repair • Availability of

spares• Loss of generation

– downtime

1 L. M. Moore and H. N. Post, “Five years of operating experience at a large, utility-scale photovoltaic generating plant,” Prog. Photovolt. Res. Applicat., vol. 16, no. 3, pp. 249–259, 2008.2 Wolfgang E., “Examples for Failures in Power Electronics Systems,” in EPE Tutorial ‘Reliability of Power Electronic Systems’, April 2007.

Distribution of failure of power component2

Unscheduled maintenance cost by subsystem1


Aluminum Electrolytic Capacitors (AEC)

31

• High energy density• Ageing: C decreases and ESR increases

1 http://img.diytrade.com/cdimg/1326126/18453230/0/1297172889/aluminum_electrolytic_capacitors.jpg2 http://www.dfrsolutions.com/wp-content/uploads/2014/06/A-New-Method-for-Testing-Electrolytic-Capacitors-to-Compare-Life-Expectancy.pdf3 http://www.okorder.com/p/electronic-aluminum-foil-used-for-cable-and-electronic-capacitor_386519.html

PaperAnode foil

Cathode foil

Tabs

Seal


Accelerated Ageing - AEC

32

• Understanding the effect of aging on circuit operation

• Accelerated aging

1 Danny Boby, Waseem Ahmad, Nikunj Agarwal, and S. Anand, "Correlation of Accelerated Lifetime in Punctured Capacitor with Normal Operating Lifetime," CPE-POWERENG'2016, , Bydgoszcz, Poland, June-July 20162 Rashmi Shukla, Md. Waseem Ahmad, Nikunj Agarwal, and S. Anand, "Accelerated Ageing of Aluminum Electrolytic Capacitor," NPEC'2015, Mumbai, India, Dec. 2015

Puncture

Oven


Package Failure Mechanism of IGBTs

33

• Layers of different material• Junction temperature variations• Mismatch in C.T.E. of different layers• Failure mechanism:

• Bond wire degradation• Die attach degradation

Solder Layer

IGBT chip

Bond wire

DBC substrate

Terminal

Base plate

Material Coefficient of thermal expansion (ppm/ 0C)

Silicon die 2.8

Bond wires (Aluminum wire) 23.1

Solder (alloy containing 96.5% tin, 3% silver and 0.5% copper) 23.5

1 Rui Wu, Frede Blaabjerg, Huai Wang, Marco Liserre, Francesco Iannuzz,”Catastrophic Failure and Fault-Tolerant Design of IGBT Power Electronic Converters- An Overview”, IEEE Trans. Ind. Electron.,Nov. 2013


Accelerated Ageing - IGBT

34

• Current with 4s on and 6s off• Increase in Temperature induced stress

1 Arun Singh et. al, "On-line Condition Monitoring of Bond Wire Degradation in IGBTOnline Health Monitoring of Aluminum Electrolytic Capacitors,” IEEE Trans. Power Electronics, 2017


Maintenance Types

35

• Estimating the health• Schedule Maintenance• Reduce downtime, easy

management of spares• Cost of condition monitoring!

Maintenance Corrective Preventive Predictive

Principle Failure Based

Periodic (Time or

other parameter)

Condition Monitoring

Based

Schedule

Reliability --

Cost High Medium Low

Downtime High Medium Low

Inventor Requirement High High Low

Additional Components

No No Yes


Low Frequency Injection

36

1 Waseem Ahmad et. al, “Low-Frequency Impedance Monitoring and Corresponding Failure Criteria for Aluminum Electrolytic Capacitors”, IEEE Trans. Industrial Electronics, 2017

DC-DC 2

High frequency measurement require large sampling rate


Measurement of Low Frequency

37


DC-DC 2

• Where to sample? -- to get average over switching cycle

• CCM – mid point, highest or lowest counter value in DSP


Simulation Results

38


DC-DC 2

• Injected signal: 120Hz• DCM operation


Experimental Results

39


DC-DC 2

• Same specifications as simulation


Effect of Temperature - Experimentation

40


DC-DC 2

• Zc (at low frequency) -- changes with operating temperature

• Issues:1. Wrong triggering of failure criteria2. How to accurately determine the

failure criteria• Characterize initially• Measure / Estimate Capacitor Temperature• Determine health w.r.t initial value at same

temperature


Extraction Loss in Grid-Feeding PV System

41

• Single Stage Single Phase PV Inverter• VPV oscillates at 100Hz

• Reduction in power extraction efficiency with aging

• Users perspective – max profit

1 Nikunj Agarwal et. al, “Lifetime Monitoring of Electrolytic Capacitor to Maximize Earnings From Grid-Feeding PV System”, IEEE Trans. Industrial Electronics, 2016

DC-AC 1


Proposed Solution

42


𝑃𝐸𝐸 =

1𝑇 ∫

𝑝 𝑑𝑡

𝑃

DC-AC 1

Degradation Model

(PoF Based)

Mission Profile

Sys Parameters

Stress Calculation (V

& I)

Calculate Revenue &

Profit

Replace, if PEEcr

Calculate PEE


How to Find PEEcritical

43


Stress CalculationDouble Fourier series analysis

PEE Calculation

Degradation (PoF based)

DC-AC 1



44


DC-AC 1



45


DC-AC 1


Health Monitoring of Capacitor Bank

46

• Bank C and ESR may not be good indicators

• Different degradation in bank

• Large number of sensors requires for individual capacitor health


IGBT Health Monitoring

47

• Bond-wire monitoring• On-state voltage monitoring• Challenges:

• Blocking high DC voltage in OFF state• Positive and negative voltage measurement• ADC compatibility• Measurement error in few mV• Output settling time in few µs

-2

-1

0

1

2

-3 -1 1 3

% E

rror

in o

n-st

ate

volta

ge m

easu

rem

ent

VON (V)

1% mismatch (Case1) 1% mismatch (Case2)0.1% mismatch (Case1) 0.1% mismatch (Case2)

1. Resistor Mismatch 2. Diodes Mismatch 3. Measurement error due to ADC quantization

0

2

4

6

8

10

400 450 500 550 600 650

I DC

(mA)

Diode Voltage (mV)

T=24°CT=24°CT=40°CT=40°CT=50°CT=50°C

(V1-V2)max

(V)

𝑅𝑓𝑅2

Measurement error due to ADC

quantization (%)15 0.1 0.24410 0.15 0.16275 0.3 0.081333 0.5 0.0488


Experimental Results of Measurement Circuit

48


IGBT Online Health Monitoring

49

• On-state voltage is also affected by:• Junction temperature: Load, ambient temp.• Solder Fatigue

• Monitoring at inflection point


IGBT Monitoring in Half Bridge Inverter

50

• Monitoring at inflection point

1 Arun Singh et. al, “On-line Condition Monitoring of Bond Wire Degradation in IGBT”, IEEE Trans. Power Electronics, 2016

IGBT 1


IGBT Monitoring in Half Bridge Inverter

51

1 Arun Singh et. al, “On-line Condition Monitoring of Bond Wire Degradation in IGBT”, IEEE Trans. Power Electronics, 2016

IGBT 1



52

Inverter Circuit

Controls

Grid









Intermittence and Scheduling

53

• 8th Aug. 2015, (SERE, IIT Kanpur, India)• Intermittence due to clouds• Issues:

• In distribution system: P-V coupling• Voltage variations• Large no. of OLTC switching

• Increased penetration• Large reserve requirements• Dynamics, Stability

• Difference in load and generation profile

• Stress on conventional generators• Limited utilization of renewables


Challenges in Renewable Integration Intermittent generation dependent on season, weather and other

parameters-Power balancing .Voltage and frequency control; most of these sources do not have

reactive power generation.The sudden generation loss can lead to transient angle and voltage

instability.Stability issue more challenging due to inertia less generation, e.g. solar.Power Quality issues-Harmonics, flicker, under voltage ride through

capabilityPower management and Maximum power point tracking.

54


Upcoming Grid Standard

55

• Challenges on Grid due to increased penetration of solar PV

• Frequency regulation• Voltage regulation• Peak load / uncertainties – Load and Source• LVRT / HVRT

• IEEE Std 1547a™-2014 (Amendment to IEEE Std 1547™-2003)

• California Rule 21 – North America• Central Electricity Authority – Technical Standard

for Connectivity to Grid• Regulations 2007 and Amendment in 2013• Proposed draft amendments in 2016


IEEE 1547a - 2014

56

• IEEE Standard for Interconnecting Distributed Resources with Electric Power Systems

• IEEE Std 1547a™-2014 (Amendment to IEEE Std 1547™-2003) • Major Changes:

• EPS – Electric Power System; DR – Distributed Resources

1 http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6818982


IEEE 1547a - 2014

57



IEEE 1547a - 2014

58



IEEE 1547a - 2014

59



IEEE 1547a - 2014

60



CEA – Technical Standards for Connectivity to Grid

61

• Central Electricity Authority – Technical Standard for Connectivity to Grid• Regulations 2007 and Amendment in 2013

• Proposed draft amendments in 2016



62



63



64



65



66

And Few More Modifications …..



67


Next Gen. Solar Inverter

68

Voltage Regulati

on (VRS)

Solar feeding to

grid(MPPT)

Low Voltage

Ride Through (LVRT)

Real power primary frequency response

DC Loads

Control

Power Ramp Rate



69

Inverter Circuit

Controls

Grid









Generic DC Microgrid

1. Multiple types of sources

2. Multiple sources of same type

3. Physical distance between sources

4. Complex interconnection

70


Primary Control Objective

1. Stable supply of dc voltage Stability

2. Microgrid voltage within the specified value Low voltage regulation

71


Secondary Control Objectives

1. Optimal utilization of renewable sources

• Maximum Power Point Tracking

• Reduce power extraction during light load condition

72


Secondary Control Objectives

2. Optimal utilization of storage capacity• Two similar storage system should

share the power as per their ratings

73


Tertiary Control Objectives

1. Scheduling of sources within microgrid

2. Interactions with other microgrids

3. Main AC Grid interaction should be close to the scheduled power

Penalty on deviation from scheduled power

74

Hierarchical Control• Tertiary control • aka energy management system• communicates with DSO / TSO and

secondary control• Advanced Distribution Management

System (ADMS)• prepares the source and storage

dispatch schedule.

• Secondary controller• Power supplied by different sources is

in proportion to that scheduled (base value)

• Voltage regulation• Centralized or Distributed

• Primary Control • compensate for instantaneous

mismatch between scheduled power and power demanded by loads.

• Generates the voltage reference signals for source.

• Conventionally droop controller 75


Dynamic Overcurrent Saturation of Distributed Sources in a DC Microgrid System Overloading of a source converter during large load transient

Source connected near to load, provide large transient current

Conventionally, use a static current limit for converters

Significant disturbances, when converter recovers from saturation

Dynamic overcurrent saturation technique is proposed

Sandeep Anand - IIT Kanpur

D. Dhua, A. B. Shyam, Sandeep Anand, and S. R. Sahoo, “Dynamic Overcurrent Saturation of Distributed Sources in a DC Microgrid System”, 20th National Power Systems Conference, NPSC’18, Tiruchirappalli, India, Dec 2018.


Ideal Current-Based Distributed Control to Compensate Line Impedance in DC Microgrid

Interconnecting cable deteriorates proportional current sharing and voltage regulation

Ideal current based controller which changes the droop gain. Shift in nominal voltage to ensure average microgrid voltage with-in limits. Communication for exchange of voltage and current information.


S. Islam, S. Agarwal, A. B. Shyam, A. Ingle, S. Anand, and S. R. Sahoo, "Ideal current-based distributed control to compensate line impedance in DC microgrid," in IET Power Electronics, vol. 11, no. 7, pp. 1178-1186, Jun. 2018.


Communication Delay


S. Islam, S. Agarwal, A. B. Shyam, A. Ingle, S. Anand, and S. R. Sahoo, "Ideal current-based distributed control to compensate line impedance in DC microgrid," in IET Power Electronics, vol. 11, no. 7, pp. 1178-1186, Jun. 2018.

Experimental results. Source voltage and currents for: (voltage: 12.5 V/div, current: 200 mA/div, time-axis: 4 s/div) (a) Conventional droop controller, (b) Proposed controller without voltage shift, (c) Proposed controller with voltage shift, (d) Proposed controller with voltage shift and communication delay of 300 ms

Eigenvalue Loci for increase in delay time


Quality Index Based Distributed Secondary Controller

With communicating only source current information, both proportional current sharing and low voltage regulation are achieved.

Quality Index is defined as weighted sum of the terms corresponding to voltage regulation and current shared by each source.

Droop gain is changed based on slop of quality index vs droop gain to achieve a low quality index.

Works for full and reduced communication network.


A. Ingle, A. B. Shyam, S. R. Sahoo and S. Anand, "Quality-Index Based Distributed Secondary Controller for a Low-Voltage DC Microgrid," in IEEE Transactions on Industrial Electronics, vol. 65, no. 9, pp. 7004-7014, Sept. 2018.

Fig: Trend of square of current sharing error, square of voltageregulation and quality index versus droop gain for a twoconverter system.

Fig: Variation of quality indices with the algorithm in operationfor a two converter system.


Quality Index Based Distributed Secondary Controller


A. Ingle, A. B. Shyam, S. R. Sahoo and S. Anand, "Quality-Index Based Distributed Secondary Controller for a Low-Voltage DC Microgrid," in IEEE Transactions on Industrial Electronics, vol. 65, no. 9, pp. 7004-7014, Sept. 2018.

Experimental results for proposed method with initial droop gain of 25 . (a) Source voltages; Y-axis: 5 V/div, Y-min: 165 V, Y-max: 215 V, (b) source currents; Y-axis: 0.125 A/div, Y-min: 0.375 A, Y-max: 1.625 A and (c) instantaneous droop gains; Y-axis: 7.1 /div, Y-min: –25.98 , Y-max: 45.05 ; X-axis: 4 s/div.


Reduced Communication Based Local Averaging Method

Reduced communication-based cooperative / consensus control strategy is proposed.

Each controller estimates the average per-unit current with the available neighbour current information.

Droop gain and nominal voltage are changed based on the locally estimated per-unit current.


S. Thomas, S. R. Sahoo and S. Anand, "Reduced Communication Based Local Averaging Method for Low Voltage DC Microgrid," 2017 7th International Conference on Power Systems (ICPS), Pune, 2017, pp. 497-502.

Fig: Simulation results: Converter output currents (a) for proposedscheme, and (b) for full communication based scheme.


Performance Analysis of Reduced Communication Network

Compares the performance of the secondary controller with reduced and full communication topologies.

It is shown that for large values of gain m, reduced communication based scheme shows similar settling as that of full communication based scheme.


A. B. Shyam, A. Ingle, S. R. Sahoo and S. Anand, "Performance Analysis of Reduced Communication Network in DC Microgrid," 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia), Singapore, 2018, pp. 976-981.

Fig: Locus of dominant poles of the system with reducedcommunication on varying m.


Grid Side Converter - Islanding Detection

IEEE 1547a-2014: Islanding detection within 0.16-2s

Passive Methods Easy to implement Under/over voltage/frequency, rate of change of voltage/frequency Significant Non- Detection Zone (NDZ) – P and Q matching between

inverter and load.

Active Methods reduces NDZ Slip Mode Frequency Shift (SMS) Injection of small disturbances into the system Detects even in case of P and Q matching NDZ for low P load with ωr ≈ 50Hz


)2

sin(m

gmSMS f

ff


Proposed Islanding Detection Method

Uses Inverter reactive power as a function of frequency.

Even if the load has zero real power consumption, the proposed technique works which was not the case with SMS method.

P. Kumar, A. Shukla, S. Anand, S. Pundir and S. Sarkar, "A Modified SMS Islanding Detection Technique for Reduced Non Detection Zone," 2018 20th European Conference on Power Electronics and Applications (EPE'18 ECCE Europe), Riga, 2018, pp. P.1-P.9.

SMS technique with Load-1 (islanding is not detected)

Parameter Value

Load-1

R,L,C 211.6Ω, 12.7 mH, 798μF

Quality factor 53.02

Load-2

R,L,C 11.98Ω, 12.7 mH, 798μF

Quality factor 3.0

Proposed method with load-1 and 2

)2

(m

gminv f

ffQQ


Developed Laboratory Microgrid Prototype

• Key Features: • CAN Communication among all four converters• Each converter with integrated dc source and controller• Complete in-house development – easy debugging• Integration of microgrid prototype with real time simulator (in

future)


PERI Laboratory IIT KANPUR 87

Acknowledgements

Thank You

Suggestions / Comments / [email protected]

Web: https://www.perilab.org/

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Renewable Integration (Solar PV) and Microgrid - IIT Kanpur