SIST EN 62116:2011
(Main)Test procedure of islanding prevention measures for utility - interconnected photovoltaic inverters
Test procedure of islanding prevention measures for utility - interconnected photovoltaic inverters
The purpose of this European Standard is to provide a test procedure to evaluate the performance of islanding prevention measures used with utility-interconnected PV systems. This standard does not specify settings parameters (voltage and frequency trip magnitude and trip time) nor pass/fail criteria, because the EN 50438 and/or National standards and/or grid codes should be taken into account for this purpose.
This standard describes a guideline for testing the performance of automatic islanding prevention measures installed in or with single or multi-phase utility interactive PV inverters connected to the utility grid. The test procedure and criteria described are minimum requirements that will allow repeatability. Additional requirements or more stringent criteria may be specified if demonstrable risk can be shown. Inverters and other devices meeting the requirements of this standard are considered non-islanding as defined in CLC/TS 61836.
This standard may be applied to other types of utility-interconnected systems (e.g. inverterbased
microturbine and fuel cells, induction and synchronous machines). However, technical review may be necessary for other than inverter-based PV systems.
Alternative testing procedures to evaluate the performance of islanding prevention may be allowed by national standards and/or grid codes.
Prüfverfahren für Maßnahmen zur Verhinderung der Inselbildung für Versorgungsunternehmen in Wechselwirkung mit Photovoltaik - Wechselrichtern
Procédure d'essai des mesures de prévention contre l'ilotage pour onduleurs photovoltaïques interconnectés au réseau public
La CEI 62116:2008 décrit des lignes directrices pour les essais de performance des mesures de prévention contre l'îlotage automatique installées dans ou avec des onduleurs PV interactifs avec le réseau public monophasés ou multiphasés, connectés au réseau public d'électricité. La procédure et les critères d'essai décrits sont les exigences minimales qui permettent la répétabilité. Des exigences supplémentaires ou des critères plus sévères peuvent être spécifiés si l'on peut démontrer l'existence de risque. Les onduleurs et autres dispositifs satisfaisant aux exigences de cette norme sont considérés comme étant sans îlotage, comme cela est défini dans la CEI 61727.
Preskusni postopki za ukrepe proti otočnemu delovanju fotonapetostnih razsmernikov, povezanih na omrežje (IEC 62116:2008, spremenjen)
Namen tega evropskega standarda je zagotoviti preskusni postopek za ovrednotenje učinka ukrepov proti otočnemu delovanju, ki se uporabljajo s fotonapetostnimi razsmerniki, povezanimi na omrežje. Ta standard ne določa nastavitvenih parametrov (napetosti in velikosti frekvenčnega preklopa ter časa preklopa) in meril za uspešnost/neuspešnost, ker je treba za to upoštevati EN 50438 in/ali nacionalne standarde in/ali pravilnike.
Ta standard opisuje smernico za preskušanje učinkovitosti avtomatskih ukrepov proti otočnemu delovanju, nameščenih v eno- ali večfaznih interaktivnih fotonapetostnih razsmernikih, povezanih na omrežje, ali skupaj z njimi. Opisani preskusni postopki in merila so minimalne zahteve, ki omogočajo ponovljivost. Dodatne zahteve ali ostrejša merila se lahko določijo, če se pokaže dokazljivo tveganje. Za razsmernike in druge pripomočke, ki izpolnjujejo zahteve tega standarda, velja, da nimajo otočnega delovanja, kot je opredeljeno v CLC/TS 61836.
Ta standard lahko velja za druge vrste sistemov, povezanih na omrežje (npr. mikroturbinske in gorivne celice na osnovi razsmernikov, indukcijske in sinhrone stroje). Za druge fotonapetostne sisteme, ki ne temeljijo na razsmernikih, je lahko potreben tehnični pregled.
Nacionalni standardi in/ali pravilniki lahko omogočajo alternativne preskusne postopke za vrednotenje učinkovitosti ukrepov proti otočnemu delovanju.
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 62116:2011
01-maj-2011
3UHVNXVQLSRVWRSNL]DXNUHSHSURWLRWRþQHPXGHORYDQMXIRWRQDSHWRVWQLK
UD]VPHUQLNRYSRYH]DQLKQDRPUHåMH ,(& VSUHPHQMHQ
Test procedure of islanding prevention measures for utility - interconnected photovoltaic
inverters
Prüfverfahren für Maßnahmen zur Verhinderung der Inselbildung für
Versorgungsunternehmen in Wechselwirkung mit Photovoltaik - Wechselrichtern
Procédure d'essai des mesures de prévention contre l'ilotage pour onduleurs
photovoltaïques interconnectés au réseau public
Ta slovenski standard je istoveten z: EN 62116:2011
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 62116:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 62116:2011
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SIST EN 62116:2011
EUROPEAN STANDARD
EN 62116
NORME EUROPÉENNE
March 2011
EUROPÄISCHE NORM
ICS 27.160
English version
Test procedure of islanding prevention measures for utility-
interconnected photovoltaic inverters
(IEC 62116:2008, modified)
Procédure d'essai des mesures de Prüfverfahren für Maßnahmen zur
prévention contre l'ilotage pour onduleurs Verhinderung der Inselbildung für
photovoltaïques interconnectés au réseau Versorgungsunternehmen in
public Wechselwirkung mit Photovoltaik-
(CEI 62116:2008, modifiée) Wechselrichtern
(IEC 62116:2008, modifiziert)
This European Standard was approved by CENELEC on 2011-01-02. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Management Centre: Avenue Marnix 17, B - 1000 Brussels
© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62116:2011 E
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SIST EN 62116:2011
EN 62116:2011 – 2 –
Foreword
This European Standard consists of the text of the International Standard IEC 62116:2008
together with common modifications prepared by the Technical Committee CENELEC TC 82,
Solar photovoltaic energy systems.
The text of the draft was submitted to the formal vote (see BT decision D136/C054) and was
accepted by CENELEC as EN 62116 on 2011-01-02.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2012-01-02
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2014-01-02
This European Standard consists of IEC 62116:2008 with some common modifications that
have been developed within CLC/TC 82 and are identified in red and/or by a vertical line in
the left margin of the text.
The scope of the common modifications is to add more detailed information on the application
of the test procedure of islanding prevention measures.
__________
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Contents
Introduction . 4
1 Scope and object . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Testing circuit . 7
5 Testing equipment . 8
5.1 Measuring instruments . 8
5.2 DC power source . 8
5.2.1 PV array simulator . 9
5.2.2 PV array . 9
5.2.3 Current and voltage limited DC power supply with series resistance . 9
5.3 AC power source . 10
5.4 AC loads . 10
6 Test for single or multi-phase inverter . 10
6.1 Test procedure. 10
6.2 Pass/fail criteria . 13
7 Documentation . 14
Annex A (informative) Islanding as it applies to PV systems. 17
Annex B (informative) Test for independent islanding detection device (relay) . 19
Annex C (informative) Gate blocking signal . 21
Bibliography . 22
Figure 1 – Test circuit for islanding detection function in a power conditioner (inverter) .8
Figure B.1 – Test circuit for independent islanding detection device (relay) . 19
Table 1 – Parameters to be measured in real time .7
Table 2 – Specification of array simulator (test conditions).9
Table 3 – PV array test conditions .9
Table 4 – AC power source requirements . 10
Table 5 – Test conditions . . 11
Table 6 – Load imbalance (active, reactive load) for test condition A . 13
Table 7 – Load imbalance (reactive load) for test condition B (EUT output = 50 % – 66 %)
and test condition C (EUT output = 25 % – 33 %) . 13
Table 8 – Specification of the EUT provided by manufacturer (example) . 14
Table 9 – List of tested condition and run on time (example) . 15
Table 10 – Specification of testing equipment (example) . 16
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SIST EN 62116:2011
EN 62116:2011 – 4 –
Introduction
Islanding is a condition in which a portion of an electric power grid, containing both load and
generation, is isolated from the remainder of the electric power grid. This situation is one with
which electric power providers (utilities) must regularly contend. When an island is created
purposely by the controlling utility — to isolate large sections of the utility grid, for example —
it is called an intentional island. Conversely, an unintentional island can be created when a
segment of the utility grid containing only customer-owned generation and load is isolated
from the utility control.
Normally, the customer-owned generation is required to sense the absence of utility-
controlled generation and cease energizing the grid. However, when the generation and load
within the segment are well balanced prior to the isolation event, the utility is providing little
power to the grid segment, thus making it difficult to detect when the isolation occurs.
Damage can occur to customer equipment if the generation in the island, no longer under
utility control, operates outside of normal voltage and frequency conditions. Customer and
utility equipment can be damaged if the main grid recloses into the island out of
synchronization. Energized lines within the island present a shock hazard to unsuspecting
utility line-workers and network users who think the lines and their equipment are dead.
The PV Industry has pioneered the development of islanding detection and prevention
measures. To satisfy the concerns of electric power providers, commercially-available utility-
interconnected PV inverters have implemented a variety of islanding detection and prevention
(also called anti-islanding) techniques. The industry has also developed a test procedure to
demonstrate the efficiency of these anti-islanding techniques; that procedure is the subject of
this document.
This standard provides a consensus test procedure to evaluate the efficiency of islanding
prevention measures used by the power conditioner of utility-interconnected PV systems.
Note that while this document specifically addresses inverters for photovoltaic systems, with
some modifications the setup and procedure may also be used to evaluate inverters used with
other generation sources or to evaluate separate anti-islanding devices intended for use in
conjunction with PV inverters or other generation sources acting as or supplementing the anti-
islanding feature of those sources.
Inverters and other devices meeting the requirements of this document can be considered
non-islanding, meaning that under reasonable conditions, the device will detect island
conditions and cease to energize the public electric power grid.
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1 Scope and object
The purpose of this European Standard is to provide a test procedure to evaluate the
performance of islanding prevention measures used with utility-interconnected PV systems.
This standard does not specify settings parameters (voltage and frequency trip magnitude and
trip time) nor pass/fail criteria, because the EN 50438 and/or National standards and/or grid
codes should be taken into account for this purpose.
This standard describes a guideline for testing the performance of automatic islanding
prevention measures installed in or with single or multi-phase utility interactive PV inverters
connected to the utility grid. The test procedure and criteria described are minimum
requirements that will allow repeatability. Additional requirements or more stringent criteria
may be specified if demonstrable risk can be shown. Inverters and other devices meeting the
requirements of this standard are considered non-islanding as defined in CLC/TS 61836.
This standard may be applied to other types of utility-interconnected systems (e.g. inverter-
based microturbine and fuel cells, induction and synchronous machines). However, technical
review may be necessary for other than inverter-based PV systems.
Alternative testing procedures to evaluate the performance of islanding prevention may be
allowed by national standards and/or grid codes.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition citied applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
EN 61727, Photovoltaic (PV) systems – Characteristics of the utility interface (IEC 61727)
CLC/TS 61836, Solar photovoltaic energy systems – Terms, definitions and symbols
(IEC/TS 61836)
EN 50438, Requirements for the connection of micro-generators in parallel with public low-
voltage distribution networks
3 Terms and definitions
For the purposes of this document, the terms and definitions of CLC/TS 61836 apply as well
as the following.
3.1
PV array simulator
DC power source used to simulate PV array output
3.2
EUT (Equipment Under Test)
EUT indicates the inverter or anti-islanding device on which these tests are performed
3.3
MPPT (Maximum Power Point Tracking)
MPPT is a PV array control strategy used to maximize the output of the system under the
prevailing conditions
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SIST EN 62116:2011
EN 62116:2011 – 6 –
3.4
island
a state in which a portion of the electric utility grid, containing load and generation, continues
to operate isolated from the rest of the grid. The generation and loads may be any
combination of customer-owned and utility-owned.
3.5
intentional island
an island that is intentionally created, usually to restore or maintain power to a section of the
utility grid affected by a fault. The generation and loads may be any combination of customer-
owned and utility-owned, but there is an implicit or explicit agreement between the controlling
utility and the operators of customer-owned generation for this situation.
3.6
quality factor, Q
f
a measure of the strength of resonance of the islanding test load.
NOTE In a parallel resonant circuit, such as a load on a power system
C
Q = R
f
L
where
Q is quality factor
f
R is effective load resistance
C is reactive load capacitance (including shunt capacitors)
L is reactive load inductance
On a power system with active power, P, and reactive powers, Q , for inductive load, and Q
L C
for capacitive load, Q can be determined by
f
Q =()1 P Q ⋅Q
f L C
where
P is active power, in W
Q is inductive load, in VAr
L
Q is capacitive load, in VAr
C
3.7
run-on time, t
R
the amount of time that an unintentional island condition exists. Run-on time is defined as the
interval between the opening of the switch S1 (Figure 1) and the cessation of EUT output
current.
3.8
stopping signal
a signal provided by the inverter indicating it has ceased energizing its utility grid-connected
output terminals (See Annex C)
3.9
unintentional island
an islanding condition in which the generation within the island that is supposed to cease
energizing the utility grid instead continues to energize the utility grid
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4 Testing circuit
The testing circuit shown in Figure 1 shall be employed. Similar circuits shall be used for
three-phase output.
Parameters to be measured are shown in Table 1 and Figure 1. Parameters to be recorded in
the test report are discussed in Clause 7.
Table 1 – Parameters to be measured in real time
Parameter Symbol Units
a,b
EUT DC input
DC voltage V V
dc
I
DC current dc A
DC power P W
dc
c
Irradiance G W/m²
EUT AC output
b, d, e
AC voltage V V
EUT
b, d, e
I
AC current EUT A
b
Active power P W
EUT
b
Reactive power Q VA
EUT
d, e, f, g
Voltage waveform
d, e, f, g
Current waveform
d
EUT (relay) output control signal
Run-on time t s
R
h
Stopping signal SS --
b
Test load
Resistive load current I A
R
Inductive load current I A
L
Capacitive load current I A
C
b
AC (utility) power source
i
Utility active power P W
ac
i
Utility reactive power Q VAr
ac
i
Utility current I A
ac
a
If applicable.
b
Record values measured before switch S1 is opened.
c
Recorded when the test is carried out using a PV array, Pyranometer should be fast response silicon-
type not thermopile-type.
d
The response time of voltage and current transducer shall be suitable for the sampling rate used.
e
The waveform, AC voltage and current, shall be measured on all phases.
f
The waveform data shall be recorded from the beginning of the islanding test until the EUT ceases
output. The measurement of time shall have an accuracy and resolution of better than 1 ms.
g
When the waveform is recorded, the synchronizing signal of the S1 opening and stopping signal may be
simultaneously recorded.
h
If available from the EUT.
i
Signal shall be filtered as necessary to provide fundamental (50 Hz or 60 Hz) frequency value.
Fundamental values will ignore incidental harmonics, caused by utility voltage distortion, absorbed by
the load and EUT filtering capacitors.
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Trigger
SIST EN 62116:2011
EN 62116:2011 – 8 –
Waveform
monitor
DC power AC power
V I V I I P
dc dc EUT EUT ac ac
. EUT
source source
(inverter)
P P Q Q
dc EUT EUT ac
(PV) (utility)
S1
S2
I I I
R L C
AC loads
Figure 1 – Test circuit for islanding detection function in a power conditioner (inverter)
5 Testing equipment
5.1 Measuring instruments
Waveform observation shall be measured by a device with memory function, for example, a
storage or digital oscilloscope or high speed data acquisition system. The waveform
measurement/capture device shall be able to record the waveform from the beginning of the
islanding test until the EUT ceases to energize the island. For multi-phase EUT, all phases
shall be monitored. A waveform monitor designed to detect and calculate the run-on time may
be used.
For multi-phase EUT, the test and measurement equipment shall record each phase current
and each phase-to-neutral or phase-to phase voltage, as appropriate, to determine
fundamental frequency, active and reactive power flow of the fundamental frequency over the
duration of the test. Anti-aliasing filters and sampling frequencies appropriate to the
measurement of the fundamental frequency component shall be applied. A sampling rate of
10 kHz or higher is recommended. The minimum measurement accuracy shall be 1 % or less
of rated EUT nominal output voltage and 1 % or less of rated EUT output current. Current,
active power, and reactive power measurements through switch S1 used to determine the
circuit balance conditions shall report the fundamental (50 Hz or 60 Hz) component.
5.2 DC power source
As DC power source a PV array simulator (preferred) or a PV array or a current and voltage
limited DC power supply with series resistance may be used. If the EUT can operate in utility-
interconnected mode from a storage battery, a DC power source may be used in lieu of a
battery as long as the DC power source shall not be the limiting device as far as the maximum
EUT input current is concerned.
The DC power source shall provide voltage and current necessary to meet the testing
requirements described in Clause 6.
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5.2.1 PV array simulator
A unit intended to be energized directly from a photovoltaic source shall be energized from a
supply that simulates the current-voltage characteristics and time response of a photovoltaic
array. The tests shall be conducted at the input voltage defined in Table 2 below, and the
current shall be limited to 1,5 times the rated photovoltaic input current, except when
specified otherwise by the test requirements.
A PV array simulator is recommended, however, any type of power source may be used if it
does not influence the test results.
Table 2 – Specification of array simulator (test conditions)
a
Items Conditions
Sufficient to provide maximum EUT output power and other levels specified by test conditions
Output power
of Table 5.
The response time of a simulator to a step in output voltage due to a 5 % load change, should
b
Response speed
result in a settling of the output current to within 10 % of its final value in less than 1 ms.
Excluding the variations caused by the EUT MPPT, simulator output power should remain
stable within 2 % of specified power level over the duration of the test: from the point where
Stability
load balance is achieved until the island condition is cleared or the allowable run-on time is
exceeded.
c
Fill factor 0,25 to 0,8
a
For the purpose of this standard, it is assumed that there is no influence of cell technology on islanding detection.
b
Response speed is indicated to avoid influence caused by MPPT control system, ripple frequency on DC side of a
EUT, or active methods of anti islanding.
c
Fill factor = (V × I )/(V × I ), where V and I are the maximum power point voltage and current, respectively,
mp mp oc sc mp mp
V is the open circuit voltage, and I is the short circuit current. It should be maintained at one value for all test
oc sc
conditions
5.2.2 PV array
A PV array used as the EUT input source shall be capable of EUT maximum input power at
minimum and maximum EUT input operating voltage. Testing is limited to times when the
irradiance varies by no more than 2 % over the duration of the test as measured by a silicon-
type pyranometer or reference device. It may be necessary to adjust the array configuration to
achieve the input voltage and power levels prescribed in 6.1.
Table 3 – PV array test conditions
Items Conditions
Sufficient to provide maximum EUT output power and
Output power
other levels specified by test conditions of Table 5.
Climate condition Irradiance, ambient temperature, etc.
To achieve a balanced load condition, the output of the PV array shall be stable. Thus, it is important to perform the
test only during times of stable irradiance (e.g. clear sky, near solar noon).
5.2.3 Current and voltage limited DC power supply with series resistance
A DC power source used as the EUT input source shall be capable of EUT maximum AC
output power at minimum and maximum EUT AC output operating voltage.
The power source should provide adjustable current and voltage limits, set to provide the
desired short circuit current and open circuit voltage when combined with the series and shunt
resistance described below.
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SIST EN 62116:2011
EN 62116:2011 – 10 –
A series resistance (and, optionally, a shunt resistance) should be selected to provide a fill
factor within the range shown in Table 2.
5.3 AC power source
The utility grid or other AC power source may be used as long as it meets the conditions
specified in Table 4.
Table 4 – AC power source requirements
Items Conditions
Voltage Nominal ± 2,0 %
Voltage THD < 2,5 %
Frequency Nominal ± 0,1 Hz
a
Phase angle distance 120º ± 1,5º
a
Three-phase case only
5.4 AC loads
On the AC side of the EUT, variable resistance, capacitance, and inductance shall be
connected in parallel as loads between the EUT and the AC power source. Other sources of
load, such as electronic loads, may be used if it can be shown that the source does not cause
results that are different than would be obtained with passive resistors, inductors, and
capacitors
All AC loads shall be rated for and adjustable to all test conditions. The equations for Q are
f
based upon an ideal parallel RLC circuit. For this reason, non-inductive resistors, low loss
(high Q ) inductors, and capacitors with low effective series resistance and effective series
f
inductance shall be utilized in the test circuit. Iron core inductors, if used, shall not exceed a
current THD of 2 % when operated at nominal voltage. Load components should be
conservatively rated for the voltage and power levels expected. Resistor power ratings should
be chosen so as to minimize thermally-induced drift in resistance values during the course of
the test.
Active and reactive power should be calculated (using the measurements provided in Table 1)
in each of the R, L and C legs of the load so that these parasitic parameters (and parasitics
introduced by variacs or autotransformers) are properly accounted for when calculating Q .
f
6 Test for single or multi-phase inverter
6.1 Test procedure
The following test procedure is usually conducted at ordinary ambient conditions (i.e.
25 °C ± 5 °C, 70 % up to 95 % of relative humidity RH). Moreover different ambient conditions
for tests shall be adopted if required by specific national standards or grid codes.
1)
The following test is designed for EUT consisting of a single or multi-phase inverter .
The test uses an RLC load, resonant at the EUT nominal frequency (50 Hz or 60 Hz) and
matched to the EUT output power. For multi-phase EUT, the load shall be balanced across all
2)
phases and the switch S1 as in Figure 1 shall open all phases . This test shall be performed
1)
Annex B describes the test for independent islanding detection device (relay).
2)
A loss of one or two phases in three-phase system is not considered an islanding phenomenon.
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with the EUT conditions as in Table 5, where power and voltage values are given as a percent
of EUT full output rating.
EUT settings for voltage and frequency trip parameters (magnitude and timing) can affect the
measured run-on time. Passing this test verifies that the unit will provide adequate islanding
protection for the settings tested as well as for tighter settings (e.g. an EUT that passes the
test with frequency trip settings of ± 1,5 Hz of nominal should also trip within the maximum
measured run-on time for settings of, say, ± 0,5 Hz.) Conversely, when adjusted to settings
outside of those tested, the EUT may experience extended run-on times. Frequency settings
of ± 1,5 Hz around nominal frequency and voltage settings of ± 15 % around nominal voltage,
for the purposes of this test procedure, should be wide enough to address the majority of
utility requirements. Note that as trip settings are widened, more aggressive active anti-
islanding schemes may be required that could negatively impact power quality.
Table 5 – Test conditions
EUT AC Output EUT DC input
4)
Condition EUT trip settings
3)
Active Power, P DC Voltage, Vdc
EUT
A Voltage and frequency trip settings
1)
Maximum > 90 % of MPPT input voltage range according to National standards
and/or grid codes.
Voltage and frequency trip settings
50 % – 66 % of 50 % of rated input voltage range,
B according to National standards
maximum ± 10 %
and/or grid codes.
Voltage and frequency trip settings
2)
25 % – 33 % of < 10 % of rated MPPT input voltage
C according to National standards
maximum range
and/or grid codes.
1)
Maximum EUT output power condition should be achieved using the maximum allowable input power. Actual output
power may exceed nominal rated output.
2)
Or minimum allowable EUT output level if greater than 33 %.
3)
Based on EUT rated input operating range. For example, If range is between X volts and Y volts, 90 % of
range = X + 0,9 × (Y – X). Y shall not exceed 0,8 × EUT maximum system voltage (i.e. maximum allowable array
open circuit voltage). In any case, the EUT should not be operated outside of its allowable input voltage range.
4)
The voltage and frequency trip magnitude and trip time settings, which the unit shall be tested with, should take into
account the National standards and/or grid codes (for example, as reported in EN 50438 for micro-generators).
a) Determine EUT test output power, P , to be used from Table 5. Test conditions A, B,
EUT
and C may be performed in any order convenient to testing.
b) By adjusting the DC input source, operate the EUT at the selected P and measure
EUT
EUT reactive power output, Q , as follows. The utility disconnect switch S1 should be
EUT
closed. With no local load connected (that is, S2 is open so that the RLC load is not
connected at this time), and the EUT connected to the utility (S1 is closed), turn the EUT
on and operate it at the output determined in step a). Measure the fundamental frequency
(50 Hz or 60 Hz) active and reactive power flow, P and Q . The active power, P ,
ac ac ac
should be equal P . The reactive power, Q measured in this step is designated Q in
EUT ac EUT
the following steps.
NOTE EUT output for condition A is achieved by providing sufficient (excess) input power to allow unit
to produce its maximum output without causing it to shutdown. Condition B is achieved by adjusting the DC
input power source, if the EUT provides this mode of operation. Condition C is achieved using inverter control
to limit the output power, if the EUT
...
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