evaluation of control methods to prevent prime-mover stalling in a mixed source microgrid ·...

Evaluation of Control Methods to Prevent Prime-mover

Stalling in a Mixed Source Microgrid

Mariana Pulcherio Student Member, IEEE

The Ohio State University

Columbus, OH 43210, USA

Email: [email protected]

Ajit A. Renjit Student Member, IEEE




Mahesh S. Illindala Senior Member, IEEE




Amrit S. Khalsa Member, IEEE

American Electric Power

Groveport, OH 43125, USA


Joseph H. Eto Member, IEEE

Lawrence Berkeley National Laboratory

Berkeley, CA 94720, USA


Abstract—For a microgrid with a mix of distributed energy

resources (DERs), major challenges on its survivability are

found in the islanded condition. In particular, a sudden loss of

generation or a large and fluctuating load could force the

microgrid to operate near its capacity limits. Such a situation

can cause a cascading collapse of the system, even when the

load demand is within the DER’s kW rating as observed

during several tests at the Consortium for Electric Reliability

Technology Solutions (CERTS) Microgrid Test Bed. This

paper analyzes the prime-mover stalling phenomena behind

the system collapse. It highlights how the reserve margin of the

system is lowered during transient conditions. Furthermore,

two control methods are evaluated to resolve the microgrid

collapse problem.

Index Terms—Energy resources, governors, industrial power

systems, inverters, power system modeling, synchronous

generators, control systems, internal combustion engines.

I. INTRODUCTION

Distributed energy resources (DERs) are small rated

energy generation and storage technologies installed within

the electric distribution system [1]. They include wind

turbines, photovoltaics (PV), fuel cells, microturbines,

reciprocating engines, combustion turbines, cogeneration,

and energy storage systems [2]−[6]. A practical scenario

involves integration of various kinds of DERs, known as

mixed source microgrid, to supply the load demand.

Many papers were published on the dynamic behavior of

a microgrid comprising a mix of synchronous generator-

based and inverter-based DERs [7]−[11]. In [7], the load

demand is met by the microgrid where inverter-based DER is

programmed like a virtual synchronous generator with droop

controls. An investigation was carried out in [8] to find the

cause for poor transient load sharing in an islanded

microgrid. In [9] and [10], a modified droop control

technique and virtual impedance was proposed to limit the

inverter’s current during overloads. In summary, all these

papers analyzed the microgrid performance assuming normal

operating conditions.

However, major challenges are found when the mixed

source microgrid operates in the islanded mode of operation

near its capacity limits. In particular, the survivability of

microgrid is at risk when it experiences a s u d d e n loss

of generation from even a single large DER. Similar

situation can result when a large and fluctuating load

condition happens in an industrial power system. These

could lead the entire system to a cascading collapse [12].

Recently, several tests were carried out at the Consortium

for Electric Reliability Technology Solutions (CERTS)

Microgrid test bed at American Electric Power. During the

experimental investigation, it was observed that a large

electrical load demand, sometimes even within the DER’s

kW-rating, could result in a frequency/voltage collapse due

to prime-mover stalling. In a reciprocating engine driven

synchronous generator-based DER (i.e., genset), the prime-

mover speed is proportional to the DER’s frequency. Hence,

the stalling in genset causes a frequency collapse in the

microgrid. By contrast, the prime-mover stalling in an

inverter-based DER results in a voltage collapse [13]. This is

because the inverter-based DER has an additional power

conditioning stage after the permanent magnet synchronous

generator (PMSG). This work was supported by the Office of Electricity Delivery and

Energy Reliability, Transmission Reliability Program of the U.S. Department of Energy under subcontract 7004227 with The Ohio State

University administered by the Lawrence Berkeley National Laboratory.

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

When multiple DERs are integrated in the microgrid,

they are expected to share the reserve margins with each

other. However, the system collapsed in few test cases

conducted at the CERTS Microgrid. This paper highlights

that the reserve margin is lowered under transient

conditions. Furthermore, a root cause analysis is carried out

and two control methods are evaluated for resolving the

problem.

II. MIXED SOURCE MICROGRID

A. System under Test

A mixed source microgrid has a diversity of distributed

energy resources (DERs) to support the load demand. For

example, as shown in Fig. 1, it can include reciprocating

engine driven synchronous generator-based DER1 (i.e.,

genset) and inverter-based DER2. These dispatchable energy

resources act as voltage sources and have frequency droop

controls [1]. In addition, a renewable resource like

solar/photovoltaic (PV) system is also indicated in Fig. 1.

However, this PV system is run as a grid following current

source, and hence is regarded as a negative load. Under

islanded operation of the microgrid (cf. Fig. 1), the power

balance between generation and load can be mathematically

expressed as

�� ∙ � �� ∙ � (1)

where the net load demand on DER1 and DER2 is

�� ∙ � � �� ∙ �� (2)

In this study, the load reactive power is considered to be

zero (i.e., QL = Qload = 0). Because of the intermittent power

from the renewables (��), the net load (��) can change all

of a sudden.

∴ �� (3)

where �� (4)

and �� 0 (5)

B. Problem Description Microgrid System Collapse

A particular cause of concern is the survivability of the

microgrid under sudden loss of generation from one of the

energy sources (DERs). For instance, if the PV system

suddenly stopped supplying power (PPV), it produces a

substantial change in net load demand (PL) on the remaining

two DERs (viz., DER1 and DER2). At the Consortium for

Electric Reliability Technology Solutions (CERTS)

Microgrid Test Bed [14], an experimental investigation was

carried out to study the dynamic behavior of the mixed

source microgrid. The specifications of the two reciprocating

engine driven DERs, i.e., synchronous generator-based

DER1 (i.e., genset) and inverter-based DER2 are provided in

[12], [13]. It should be noted that each DER is rated to

deliver 100 kW continuous load. Two test cases are

presented below showing different results for a large step

load change (PL) from 75 kW to 150 kW. The genset

(DER1) is run with an isochronous governor and the

inverter-based DER2 is controlled with 1% active power-

frequency (P−ω) droop.

Fig. 1. Simplified schematic of the mixed source microgrid comprising synchronous generator-based and inverter-based DERs

V��e��

V!��e��"

�� ∙ ��

X$ � X�!%�

�� ∙ ��

Engine-2 PMSG-2

Tlim2

DER-2

&'

V!�e��(

�� ∙ �� Engine-1 SG-1

Tlim1

X�!%�

DER-1

DSP Controls

Load Bank

��

Solar/PV

System

)'

�� ∙ ��

Net load change, �� ∙ � �

Power Conditioning System (PCS)

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

Test Case 1: Fig. 2 displays the dynamic response

observed during experimental testing of the mixed source

microgrid when the two DERs were given equal power

allocations at first (with Pref2 = 37.5 kW). This test case

ended in the collapse of the microgrid system upon a step

load change (PL) of 75 kW to 150 kW [12]. The inverter-

based DER2 experienced a voltage collapse at first upon the

load change. It is manifested in Fig. 2 by the large negative

reactive power (Qelec2) of DER2 that is fed by the positive

reactive power (Qelec1) of DER1 in line with (5). The

failure of DER2 caused an overload in DER1 (i.e., Pelec1) as

the net load demand of 150 kW is beyond its rated

capability of 100 kW. Therefore, the DER1 also collapsed

resulting in a cascading failure of the microgrid system.

Test Case 2: In comparison to the earlier test case, this

time the inverter-based DER2 was given zero initial power

allocation of Pref2 = 0 kW. The same 75 kW to 150 kW step

load change was tested. Fig. 3 shows selected waveforms

illustrating the dynamic response observed during

experimental testing at the CERTS Microgrid [12]. As seen

in this figure, the microgrid system survived in this test

without collapsing.

III. ROOT CAUSE ANALYSIS

A. Reserve Margin of the Microgrid System

The contrasting outcomes (for the same step load change

of 75 kW to 150 kW) realized in the islanded microgrid

system for the two test cases pose the question:

o What is the reserve margin of the microgrid system?

Reserve margin is the value of generation capacity

available to satisfy the expected load demand [15]−[18]. For

the microgrid system comprising two DERs, if the rated

capacity is denoted by PRi (i = 1, 2), the reserve margin Ri (i

= 1, 2) is derived as

*��+ � �,� � ��+ (6)

*��+ � �,� � ��+ (7)

∑* �+ � *��+ � *��+ (8)

where ∑* is the total reserve margin of the two DERs in

the microgrid system.

For the two test cases presented earlier, the reserve

margins before the 75 kW to 150 kW load change event are

determined as displayed in Table 1 and Table 2,

respectively. It should be remarked that the DER kW-ratings

�.. 0., �,� � 100+3, and�,� � 100+3 were used in arriving at these estimates.

However, the two test cases produced different outcomes

when the step load change (from 75 kW to 150 kW) took

place. Whereas the microgrid system crashed in Test Case 1,

Fig. 2. Test Case 1: Experimental results for a step load change from 75

kW to 150 kW. DER1 (genset in red): isochronous governor, DER2 (inverter-based DER in blue): Pref2 = 37.5 kW, Pmax2 = 100 kW.

Fig. 3. Test Case 2: Experimental results for a step load change from 75 kW to 150 kW. DER1 (genset in blue): isochronous governor, DER2

(inverter-based DER in red): Pref2 = 0 kW, Pmax2 = 100 kW.

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

it survived in Test Case 2. These contrasting results are

despite having the same total reserve margin �∑* at initial 75 kW load for both test cases. Therefore, further

examination is carried out into the DER kW-rating (i.e., PRi

= 100 kW) assumed earlier in estimating the reserve margin.

Table 1: Reserve margin estimation for Test Case 1 at initial 75 kW load

78*9 �,9 ��9 *9 Σ R

78*� 100 kW 37.5 kW 62.5 kW 125 kW

78*� 100 kW 37.5 kW 62.5 kW

Table 2: Reserve margin estimation for Test Case 2 at initial 75 kW load

78*9 �,9 ��9 *9 Σ R

78*� 100 kW 75 kW 25 kW 125 kW

78*� 100 kW 0 100 kW

Fig. 4 illustrates the fuel map limit of a GM 8.1L natural

gas engine [19] adopted as the prime-mover in the genset

(i.e., DER1). As seen in this figure, the power limit of the

engine prime-mover is derated at lower speeds. Hence, the

engine’s mechanical power input to the generator is

constrained to the value

:�;�<� � =�9;� ∙ >� (9)

where =�9;� is the torque limit of engine fuel map.

Fig. 5 depicts the original operating point of Test Case 1

(i.e., �� = 37.5 kW) on the speed vs. power

characteristics of the engine driven DER1 generator. In this

figure, the :�;�<� line delineates the safe zone and stalling

zone for the electrical power output from DER1 [20]. Due to

the lower inertia, the speed of rotating generator undergoes

huge swings upon a large load disturbance until the

governor controls restore the speed close to the synchronous

speed (>?@A�). Whereas the rated power is 100 kW at the

synchronous speed, the DER1 is derated at lower speeds as

observed in Fig. 5. Hence, the rated capacity of DER1 is

found to be

�,�B>� � >?@A�C � 100+3 (10)

and �,�B>� D >?@A�C D 100+3 (11)

Reserve margin is the amount of generation capacity

available to satisfy the forecast load demand. From (6), the

reserve margin for Test Case 1 can be estimated as

*�B>� � >?@A�C � 62.5+3 (12)

and *�B>� D >?@A�C D 62.5+3 (13)

Similar conclusions could be established for inverter-

based DER2 based on the engine fuel map characteristics of

its prime-mover. The rated capacity and reserve margin of

DER2 for Test Case 1 are

�,�B>� � >?@A�C � 100+3 (14)

and �,�B>� D >?@A�C D 100+3 (15)

*�B>� � >?@A�C � 62.5+3 (16)

and *�B>� D >?@A�C D 62.5+3 (17)

Thus, the reserve margin of each DER is lowered under

transient conditions. It should be mentioned that the speed

dynamics of the prime-movers in synchronous generator-

based DER1 and inverter-based DER2 vary against each

other. Hence, under load transient conditions, the total

reserve margin of the mixed source microgrid is

∑*B>� D >?@A�, >� D >?@A�C

� *�B>� D >?@A�C � *�B>� D >?@A�C

Fig. 4. Fuel map limit of GM 8.1L natural gas engine prime-mover of

genset (DER1) [19]

�� *�B>� � >?@A�C

�,�B>� D >?@A�C

Speed (rpm)

Power (kW)

Fig. 5. Effect of prime-mover speed on reserve margin

Power limit �:�;�<�)

Torque limit �=�9;�)

37.5

*�B>� D >?@A�C

�,�B>� � >?@A�C

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

∴ ∑ * B>� D >?@A�, >� D >?@A�C D 125+3 (18)

The total reserve margin for Test Case 2 also complies

with the inequality in (18). However, the transient response

in this case (cf. Fig. 3) is not the same as Test Case 1 (cf.

Fig. 2). This indicates that the two test cases have different

values of total reserve margins.

B. Prime-mover Stalling Behavior

To investigate further the root cause of microgrid

collapse, modeling and analysis was carried out. Earlier, the

co-authors developed detailed computer models that were

validated with experimental testing at CERTS Microgrid

Test Bed [12], [13], [20]−[22]. The modeling of

synchronous generator-based DER and inverter-based DER

was published in [13]. Graphical and analytical methods for

prime-mover stalling were presented in [20].

Referring back to the mixed source microgrid Test Case 1

(cf. Fig. 2), the inverter-based DER2 took the majority of

load change from 75 kW to 150 kW. This is because of its

relatively faster frequency regulation controls than the genset

speed governor controls. When the load change occurred,

the prime-mover speed varies during transient conditions.

The rate of change of kinetic energy in permanent magnet

synchronous generator (PMSG) in DER2 is governed by

∆IJ

∆K� �;��L � �� ??

(19)

where �;��L is the mechanical power input, �� is the

electrical power output, and ��?? covers all the losses in the

PMSG and inverter. When a large load change occurs, the

stored kinetic energy of prime-mover supplies the increased

demand initially until the mechanical power from engine

increases to match the electrical load. However, if the

electrical power output remains above mechanical power

input for a long duration, the stored kinetic energy is drained

thereby causing the stalling of prime-mover.

Fig. 6 illustrates the locus of electrical power and

mechanical power (minus losses) on the speed vs. power

characteristics of permanent magnet synchronous generator

(PMSG) in DER2 [12]. In this figure, the :�;�< line

delineates the safe zone and stalling zone. Since the

electrical power trajectory crossed the :�;�< line, which is

the maximum mechanical power provided by engine, the

prime-mover stalling took place. Since the PMSG speed is

proportional to its voltage, the prime-mover stalling gets

reflected as a voltage collapse in the inverter-based DER2.

The failure of inverter-based DER2 caused an overload in

genset (i.e., DER1), which led to a collapse of DER1. Fig. 7

presents the locus of electrical power and mechanical power

for the DER1. As seen in this figure, the prime-mover

stalling gets manifested as a frequency collapse because

the frequency of a generator is proportional to its speed.

It should be noted that the frequency of inverter is

decoupled from the prime-mover speed by the power

conditioning system (PCS). This is indicated in the inverter

Fig. 6. Locus of the prime-mover speed vs. power characteristics for

inverter-based DER2 in Test Case 1

Fig. 8. Locus of the inverter frequency vs. power characteristics for DER2

in Test Case 1

Fig. 7. Locus of the prime-mover speed vs. power characteristics for synchronous generator-based DER

1 in Test Case 1

EPm

ax2 lin

e

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

frequency vs. power characteristics shown in Fig. 8.

However, a collapse in the PMSG voltage cannot be

prevented from propagating through the PCS due to lack of

sufficient energy storage [13].

IV. CONTROL METHODS TO PREVENT PRIME-MOVER

STALLING

The prime-mover stalling can be prevented by restricting

the electrical power output from each DER to stay within

the safe zone of its prime-mover speed vs. power

characteristics. The load shared by each unit should be

within the available reserve margin. It was shown in the

previous section that the transient reserve margin is reduced

due of derating of DER kW-rating when its prime-mover

runs at a lower speed.

For limiting the electrical power output from a DER

�� to stay within the safe zone, the CERTS �;�<

controls [23], [24] are used in commercial products. This

section evaluates the CERTS �;�< controls and a new

control method based on limiting the maximum torque (i.e.,

=;�< controls). Such controls can be integrated with the

conventional frequency droop controllers commonly

employed in the industrial products. Therefore, these

controls cannot be implemented into the isochronous

governor controlled genset (DER1). However, these controls

are applied in the frequency controller of the inverter-based

DER2.

A. CERTS �;�< Controls

The CERTS �;�< controls offer flexibility to limit the

DER’s electrical power output �� to within the �;�<

value programmed [23], [24]. A block diagram of the

CERTS �;�< controller is shown in Fig. 9. It consists of an

integral gain controller that is inactive during normal

operation for �� D �;�< . This is implemented through a

hard limiter that clamps the integrator output to zero on the

higher side. When the electrical power output �� exceeds

the programmed �;�< value, this controller forces a

decrease in the DER’s frequency. In an interconnected

microgrid system, a temporary decrease in frequency of a

DER helps in lowering its relative phase angle and thereby

limits the unit’s electrical power generation. Fig.9. Block diagram of the CERTS �;�< controller. Frequency droop is

1% and K = 300.

Pmax

+

+

−−−−

Pelec

∑∑∑∑ MN

∆ω'*

ωnom

+

+

+

−−−−

Pelec

∑∑∑∑ ∑∑∑∑ Frequency

Droop ∆ω*

ω*

0

Pref


inverter-based DER2 in Test Case 1 with Pmax2 = 70 kW

Fig. 12. Locus of the inverter frequency vs. power characteristics for

DER2 in Test Case 1 with Pmax2 = 70 kW


synchronous generator-based DER1 in Test Case 1 with Pmax2 = 70 kW

EPm

ax2 lin

e

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

In general, the value of �;�< is programmed to match

with the maximum power that can be provided by the

engine prime-mover, which is 100 kW in the inverter-based

DER2 installed at the CERTS Microgrid. However, it was

found that �;�< � 100+3 could not prevent prime-mover

stalling for a few test cases. In fact, the plots shown for Test

Case 1 shown in Fig. 2 and Figs. 6−8 for a 75 kW to 150

kW step load change with isochronous governor controlled

DER1 and Pref2 = 37.5 kW for DER2 had been obtained

with �;�< � 100+3. This is indicated in Fig. 8 by the

constant power EPmax2 line at 100 kW.

Later, when a lower value of �;�< � 70+3 was tested

in the simulation model, the microgrid system did not

collapse. As shown in Figs. 10−12, the programming of

controller with �;�< � 70+3 has prevented prime-mover

stalling in DER2. Here, the constant power EPmax2 line is at

70 kW as shown in Fig. 12. However, it has resulted in the

reduction of generation capacity of DER2 at the

synchronous speed of prime-mover from 100 kW to 70 kW.

This has led to the proposed =;�< controls explained below.

B. Proposed =;�< Controls

As explained earlier, the transient reserve margin of the

microgrid system is lesser at lower prime-mover speeds due

to the derating of DER’s kW-rating. This finding calls for

lowering the �;�< value at the same rate as the prime-mover

speed. The proposed =;�< controller can achieve this aim as

it was designed to regulate the electrical load torque

=�� />∗. As seen in Fig. 13, this controller is only

active when the electrical load torque =�� is higher than the

programmed maximum torque value of =;�< .

Figs. 14−16 display the results of the mixed source

microgrid for Test Case 1 with =;�<� � 265RS that

corresponds to the full 100 kW rated capacity at the nominal

60 Hz frequency of inverter-based DER2. However, at lower

frequencies that are encountered under transient conditions,

the electrical power generation capacity is derated. This is

indicated in Fig. 16 by a constant torque 8�;�<� line that

varies according to the available reserve margin in the DER.

The results illustrating the performance of the proposed

=;�< controller are also shown as time-domain plots in Fig. Fig. 13. Block diagram of the proposed =;�< controller. Frequency droop

is 1% and K = 300.

Tmax

+

+

−−−−

=��

� �� >∗T

∑∑∑∑ MN

∆ω'*

ωnom

+

+

+

−−−−

Pelec

∑∑∑∑ ∑∑∑∑ Frequency

Droop ∆ω*

ω*

0

Pref


inverter-based DER2 in Test Case 1 with Tmax2 = 265 Nm

Fig. 16. Locus of the inverter frequency vs. power characteristics for

DER2 in Test Case 1 with Tmax2 = 265 Nm


synchronous generator-based DER1 in Test Case 1 with Tmax2 = 265 Nm

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

17. As seen in this figure, the microgrid system has operated

safely without collapsing for =;�<� � 265RS. Thus,

programming of DERs with the =;�< controller enables

improved coordination among interconnected DERs in a

microgrid system that is operated near its capacity limits.

V. CONCLUSION

This paper analyzed the operation of a mixed source

microgrid comprising a synchronous generator-based DER

and an inverter-based DER in an islanded condition. When a

sudden load increase or loss of generation happens, the

survivability of the microgrid is challenged when the DERs

are forced to operate near their capacity limits. It was found

that the microgrid is susceptible to a collapse due to DER

prime-mover stalling. In this paper, it was shown that the

transient reserve margin of the microgrid is lower than the

estimated value based on DER kW-ratings. To prevent the

microgrid system collapse, two control methods were

evaluated. The first method was �;�< controls, which is

used in the commercial DER equipment at the CERTS

Microgrid Test Bed. An alternative control method, namely

=;�< controls, gave a better performance. As compared to

the CERTS �;�< controls, the proposed =;�< controls could

prevent prime-mover stalling (and system collapse) at the

full capacity and nominal frequency.

ACKNOWLEDGMENTS

The work described in this paper was coordinated by the

Consortium for Electric Reliability Technology Solutions

(CERTS). The authors would like to thank R. H. Lasseter of

University of Wisconsin-Madison and David A. Klapp of

Advanced Microgrid Systems for their support during the

course of this project.

REFERENCES

[1] R. H. Lasseter, "Microgrids," in Proc. 2002 IEEE Power Eng. Soc.,

pp. 305–308.

[2] N. Jenkins, J. B. Ekanayake, and G. Strbac, Distributed Generation.London, U.K.: Institute of Engineers and Technology, 2010.

[3] D. Pudjianto, C. Ramsay, and G. Strbac, “Virtual power plant and system integration of distributed energy resources,” IET Renewable Power Generation, vol. 1, no. 1, pp. 10–16, 2007.

[4] H. L. Willis and W. G. Scott, Distributed Power Generation Planning and Evaluation, New York: Marcel Dekker, 2000.

[5] N. D. Hatziargyriou and A. P. S. Meliopoulos, “Distributed energy sources: Technical challenges,” in Proc. IEEE Power Engineering SocietyWinter Meeting, Jan. 2002, vol. 2, pp. 1017–1022.

[6] F. Katiraei and M. R. Iravani, "Power management strategies for a microgrid with multiple distributed generation units," IEEE Trans. Power Syst., vol. 21, no. 4, pp. 1821-1831, 2006.

[7] T. Vandoorn, B. Meersman, J. De Kooning, and L. Vandevelde,

"Directly-Coupled Synchronous Generators With Converter Behavior

in Islanded Microgrids", IEEE Trans. Power Syst., vol. 27, no. 3, pp. 1395-1406, 2012.

[8] A. Paquette, M. Reno, R. Harley, and D. Divan, "Sharing Transient Loads : Causes of Unequal Transient Load Sharing in Islanded Microgrid Operation", IEEE Industry Applications Magazine, vol. 20, no. 2, pp. 23-34, 2014.

[9] A. Paquette and D. Divan, "Transient droop for improved transient load sharing in microgrids", 2014 IEEE Energy Conversion Congress

and Exposition (ECCE), 2014.

[10] A. Paquette and D. Divan, "Virtual Impedance Current Limiting for

Inverters in Microgrids With Synchronous Generators", IEEE

Transactions on Industry Applications, vol. 51, no. 2, pp. 1630-1638, 2015.

[11] J. Liu, Y. Miura, and T. Ise, "Comparison of Dynamic Characteristics

Between Virtual Synchronous Generator and Droop Control in Inverter-Based Distributed Generators", IEEE Transactions on Power

Electronics, vol. 31, no. 5, pp. 3600-3611, 2016.

[12] A. A. Renjit, Modeling, Analysis and Control of Mixed Source Microgrid, Ph.D. Dissertation, Electrical and Computer Engineering, The Ohio State University, Columbus, OH, Dec. 2015.

[13] A. Renjit, M. Illindala and D. Klapp, "Modeling and analysis of the CERTS microgrid with natural gas powered distributed energy resources", 2015 IEEE/IAS 51st Industrial & Commercial Power Systems Technical Conference (I&CPS), 2015.

[14] J. Eto, R. Lasseter, B. Schenkman, J. Stevens, H. Vollkommer, D. Klapp, E. Linton, H. Hurtado, J. Roy, “CERTS microgrid laboratory test bed,” IEEE Transactions on Power Delivery, vol. 26, no. 1, pp. 325-332, Jan 2011.

[15] NERC, Long-Term Reliability Assessment Summary Data Demand and Generation Resources [Online], Available from: http://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/2014LTRA_ERATTA.pdf,2014

[16] N. Otsubo, A. Yokoyama, T. Ishizaka, N. Kitagishi, T. Mochida, T. Nishimura and H. Ikeda, "Economic evaluation of tie line

Fig. 17. Test Case 1: System dynamic response for a step load change

from 75 kW to 150 kW. DER1 (genset in red): isochronous governor,

DER2 (inverter-based DER in blue): Pref2 = 37.5 kW, Tmax2 = 265 Nm.

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

reinforcement under wide-area operation of power plants considering power supply reserve margin", 2014 International Conference on Power System Technology, 2014.

[17] C. Baldwin, D. Gaver, C. Hoffman and J. Rose, "The Use of Simulated Reserve Margins to Determine Generator Installation Dates", Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems, vol. 79, no. 3, pp. 365-369, 1960.

[18] A. Hajimiragha, M. Dadash Zadeh and S. Moazeni, "Microgrids Frequency Control Considerations Within the Framework of the Optimal Generation Scheduling Problem", IEEE Trans. Smart Grid, vol. 6, no. 2, pp. 534-547, 2015.

[19] Typical Datasheet of GM 8.1L engine, 8.1L, 8 cylinder – 496 cubic inches, General Motors, Texas. Available online at: http://www.rotatingright.com/pdf/8.1%20Litre%20Brochure.pdf.

[20] A. A. Renjit, M. S. Illindala, and D. A. Klapp, "Graphical and analytical methods for stalling analysis of engine generator sets,"

IEEE Transactions on Industry Applications, vol. 50, no. 5, pp. 2967-2975, Sep. 2014.

[21] A. A. Renjit, M. S. Illindala, R. H. Lasseter, M. J. Erickson, and D. A. Klapp, "Modeling and control of a natural gas generator set in the CERTS Microgrid," in 2013 IEEE Energy Conversion Congress and Exposition (ECCE), pp. 1640-1646, Sep. 2013.

[22] A. Mondal, M. Illindala, A. Renjit, and A. Khalsa, "Analysis of limiting bounds for stalling of natural gas genset in the CERTS microgrid test bed," 2014 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES), 2014.

[23] P. Piagi and R. H. Lasseter, “Autonomous Control of Microgrids,” in Proc. 2006 IEEE Power and Energy Society General Meeting, pp.1-8.

[24] R. H. Lasseter and P. Piagi, “Microgrid: A conceptual solution,”

in Proc. IEEE 35th Annual Power Electronics Specialists

Conference, vol.6, pp. 4285-4290.

of 9

978-1-4673-8672-2/15/$31.00 © 2016 IEEE

2016-PSEC-0041

evaluation of control methods to prevent prime-mover stalling in a mixed source microgrid ·...

Documents