CGC

Certification Specification of China General Certification Center

CGC/GF0042011

(CNCA/CTS 0004-2009A)

Technical Specification of Grid-connected

PV inverter

2011-08-22 Publish 2012-08-22 Implement

China General Certification Center Published

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Contents Contents ........................................................................................................................................... 1

FOREWORD ................................................................................................................................... 0

Technical Specification of Grid-connected PV inverter ............................................................... 1

1 Scope................................................................................................................................... 1

2 Normative references ........................................................................................................ 1

3 Terms and definitions ....................................................................................................... 2

3.1 photovoltaic grid-connected inverter.................................................................... 2

3.2 photovoltaic array simulator ................................................................................. 2

3.3 inverter AC output terminal .................................................................................. 2

3.4 maximum power point tracking .......................................................................... 2

3.5 Maximum powder point tracking efficiency ........................................................ 3

3.6 conversion efficiency, energetic (conv) ............................................................... 3

3.7 overall(total) efficiency .......................................................................................... 3

3.8 islanding .................................................................................................................. 3

3.9 intentional islanding ............................................................................................... 3

3.10 unintentional islanding ........................................................................................ 3

3.11 anti-islanding ........................................................................................................ 3

3.12 simulated utility .................................................................................................... 4

3.13 quality factor, Qf .................................................................................................. 4

3.14 resonant frequency ............................................................................................... 4

3.15 temporary ............................................................................................................. 5

4 Product Categories .......................................................................................................... 5

4.1 Product type ............................................................................................................ 5

4.2 Output power Characteristics .................................................................................. 5

5 Technical requirements ..................................................................................................... 6

5.1 Use conditions ......................................................................................................... 6

5.2 Quality of the body and structure ......................................................................... 6

5.3 Performance indicators ......................................................................................... 7

5.4 Electromagnetic Compatibility .......................................................................... 9

5.5 Protection functions ............................................................................................. 11

5.6 Array insulation resistance detection ................................................................. 13

5.7 Array residual current detection ........................................................................ 14

5.8 Communication ................................................................................................. 15

5.9 Auto on / off ....................................................................................................... 16

5.10 Soft-start ............................................................................................................. 16

5.11 Insulation resistance and dielectric strength test ............................................. 16

5.12 Degrees of protection provided by enclosure ................................................... 16

5.13 Environmental test requirements ..................................................................... 17

5.14 Power control and voltage regulation ............................................................... 17

5.15 Continuous operation test ..................................................................................... 17

5.16 Temperature rise test ......................................................................................... 17

6 Test methods .................................................................................................................... 19

CGC/GF004:2011(CNCA/CTS 0004-2009A)

6.1 Test environmental conditions............................................................................. 19

6.2 Inspecting the quality of main body and structure ........................................... 20

6.3 Performance index test ........................................................................................ 20

6.4 EMC test ............................................................................................................... 22

6.5 Protection functions tests ..................................................................................... 23

6.6 PV array insulation resistance test ........................................................................ 27

6.7 Residual current testing method ............................................................................ 27

6.8 Communication interface test ............................................................................. 28

6.9 Automatic power on/off test ................................................................................ 28

6.10 Soft start test ....................................................................................................... 28

6.11 Insulation voltage strength ................................................................................ 28

6.12 Degrees of protection provided by enclosure ................................................. 29

6.13 Environmental test ............................................................................................. 29

6.14 Power control and voltage adjustment test ...................................................... 29

6.15 Continuous operation test .................................................................................. 30

6.16 Temperature rise test ......................................................................................... 30

7 Inspection rules ............................................................................................................... 30

7.1 Inspection categories ............................................................................................... 30

7.2 Factory Inspection ................................................................................................... 32

7.3 Type test ................................................................................................................... 32

8 Logo, Packaging, Transportation, Storage .................................................................. 32

8.1 Logo .......................................................................................................................... 32

8.2 Packaging ................................................................................................................. 33

8.3 Transport ................................................................................................................. 33

8.4 Storage ...................................................................................................................... 33

Appendix A .................................................................................................................................... 34

Table A: Technical parameter table of grid-connected PV inverter ...................................... 34

Appendix B .................................................................................................................................... 36

Select of anti-islanding protection scheme .................................................................................. 36

Appendix C .................................................................................................................................... 37

Transient Voltage Protection ........................................................................................................ 37

Annex D.......................................................................................................................................... 39

Inverter efficiency ......................................................................................................................... 39

Annex E .......................................................................................................................................... 41

Test conditions for dynamic MPPT efficiency ............................................................................ 41

FOREWORD To further guide our grid-connected photovoltaic inverter technology development, promote safe,

efficient, reliable application and promotion of products and combine with the latest technical

requirements of power, the original certification technical specification CNCA/CTS0004-2009

was amended.

This technical specification is proposed by National Standardization Technical Committee 20 on

Energy Fundamentals and Management.

The technical specifications are presented and centralized by Beijing general Certification Center.

The main drafting units of this technical specification are: Beijing general Certification Center,

Sungrow Power Supply Co.,Ltd, State Grid Electric Power Research Institute, China Electric

Power Research Institute, Institute of Electrical Engineering, Chinese Academy of Sciences,

National Center Quality Supervision & Testing of Relay Protection and Automation Equipment,

Beijing Corona Science&Technology Co.,Ltd, Beijing Nego Automation Technology Co.Ltd,,

Zhuzhou CSR Times Electric Co.,Ltd.

The main units involved in this technical specification are: SMA Solar Technology AG, KACO

new energy GmbH, Siemens, Danfoss Drives A/S, Beijing Oasis New Energy Technology Co.,

Ltd., Fronius International GmbH, Beijing Jingyi Renewable Energy Engineering Co., Ltd,

Beijing Soaring Electric Technology Co., Ltd, Beijing Rijia Power Supply Co., Ltd, Beijing Jike

New Energy Technology Development Company, Suntech Power Holdings Co., Ltd, Shanghai

Solar Energy Science & Technology Co., Ltd, Anhui Jiyuan Electric Power System Tech Co., Ltd,

Sun Tech Solar Co., Ltd, Beijing Solar Power Institute, TBEA SunOasis Co., Ltd, Eifesun Sharing

Green Energy, XJ Flexible Transmission System Corporation.

The principal drafters of this technical specification are: Shilin Fan, Renxian Cao, Junjun Zhang,

Wei Feng, Huaguang Yan, Nan Jiang, Hongchao Zhang, Geng Wang, Zong Wang, Lin Wan,

Deliang Si, Taoyong Li, Yanxing Jiang, Tao Lei, Guichen Fu, Yun Li, Jie Liu, Wanyin Cai, Zhisen

Zhang, Ta Meng, Yang Zhou, Mingfeng Yu, Jing Zhang, Wei Zhao, Youquan Zhang, Xiaoge

Huang, Huo Wen.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Technical Specification of Grid-connected PV inverter

1 Scope

This technical specification provides product classification, terminology and definitions, technical

requirements, test methods, inspection rules and signs, packaging, transportation and storage for

grid-connected photovoltaic inverter.

This technical specification applies to grid-connected inverter.

2 Normative references

The following referenced documents are indispensable for the application of this document. For

dated references, only the edition cited applies. For undated references, the latest edition of the

referenced document (including any amendments) applies.

GB 4208-2008 Degrees of protection provided by enclosure(IP code)(IEC 60529:2001,IDT)

GB 7260.2-2009 Uninterruptible power system(UPS) Part 2: Electromagnetic compatibility

(EMC) requirements (IEC62040-22005,IDT)

GB 10593.1-2005 Measuring methods of environmental parameters for electric and electronic

products - Part 1: Vibration

GB/T 191-2008 Packaging storage icon logo

GB/T 2423.1-2008 Basic environmental testing procedures of electrical and electronic products

test ALow-temperature test method (IEC 60068-2-1:2007, IDT)

GB/T 2423.2-2008 Basic environmental testing procedures of electrical and electronic products

test Bhigh-temperature test method(IEC 60068-2-2:2007,IDT)

GB/T 2423.3-2006 Basic environmental testing of electrical and electronic products part 2 test

method test CabConstant damp heat test(IEC 60068-2-78:2001,IDT)

GB/T 3859.2-1993 Application guidelines of semiconductor converter(IEC 60146-1-2:1991,EQV)

GB/T 12325-2008 Power quality supply voltage allowable deviation

GB/T 12326-2008 Power quality-Voltage fluctuation and flicker

GB/T 13384-2008 General specifications for packing of mechanical and electrical product

GB/T 14549-1993 Power quality utility power grid harmonics

GB/T 15543-2008 Power quality three-phase voltage allowable degree of unbalancedness

GB/T 17626.2 Electromagnetic Compatibility Testing and measurement techniques The

Immunity Test to Electrostatic Discharge (IEC 61000-4-2:2001,IDT)

GB/T 17626.3 Electromagnetic Compatibility The Immunity Test to Radiated radio-frequency

electromagnetic field(IEC 61000-4-3:2002,IDT)

GB/T 17626.4 Electromagnetic Compatibility The Immunity Test to Electrical fast

transient/burst(IEC 61000-4-4:2004,IDT)

GB/T 17626.5 Electromagnetic Compatibility The Immunity Test to Surge (IEC

61000-4-5:2005,IDT)

GB/T 17626.6 Electromagnetic Compatibility The Immunity Test to conducted disturbances,

induced by radio-frequency fields(IEC 61000-4-6:2006,IDT)

CGC/GF004:2011(CNCA/CTS 0004-2009A)

GB/T 17626.8-2006 Electromagnetic Compatibility Testing and measurement techniques Power

frequency magnetic field immunity test(IEC 61000-4-8:2001,IDT)

GB/T 17626.11-2008 Electromagnetic Compatibility The Immunity Test to Voltage Dips, Short

Interruptions and Voltage Variations(IEC 61000-4-11:2004,IDT)

GB/T 17626.12-1998 Electromagnetic Compatibility Testing and measurement techniques

Oscillatory waves immunity test(IEC 61000-4-12:1995,IDT)

GB/T 17626.14-2005 Electromagnetic Compatibility Testing and measurement techniques

Voltage fluctuation immunity test(IEC 61000-4-14:2002,IDT)

GB/T 18479-2001 Terrestrial photovoltaic(PV) power generating systems General and

guide(IEC 61277:1995,IDT)

GB/T 20514-2006 Photovoltaic systems Power conditioners Procedure for measuring efficiency

(IEC 61683:1999,IDT)

IEC 62109-1-2010 Safety of power converters for use in PV power systems Part 1: General

requirements

IEC 62109-2-2010 Safety of power converters for use in PV power systems Part 2: Particular

requirements for inverters

EN 50530-2010 Overall efficiency of grid connected photovoltaic inverters

IEC 60990-1999 Methods of measurement of touch current and protective conductor current

IEC 62116-2008 Test procedure of islanding prevention measures for utility-interconnected

photovoltaic inverters

Q/GDW 617-2011 Technical rule for photovoltaic power station connected to power grid

Q/GDW 618-2011 Test procedures for photovoltaic power station connected to power grid

3 Terms and definitions

For this technical specification, the following terms and definitions apply.

3.1 photovoltaic grid-connected inverter

Equipment that converts direct current (dc) from solar cells to alternating current (ac). Note1:Mentioned inverter in this specification refer to grid-connected PV inverter Note2:Technical requirements and test methods in the specification do not apply to the inverter of AC MODULE 3.2 photovoltaic array simulator

Current source that simulates static and dynamic PV array current and voltage characteristics. 3.3 inverter AC output terminal

Connection point of inverter, local ac load and grid.

3.4 maximum power point tracking

Automatic adjustment in order to abtain the utmost power output from connected PV array, by tracking and controlling the variation of output voltage and current,which resulting from the variation of surface temperature and solar irradiation of PV module.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

3.5 Maximum powder point tracking efficiency

ratio of the energy drawn by the device under test within a defined measuring period TM to the

energy provided theoretically by the PV simulator in the maximum power point (MPP):

where

PDC(t) instantaneous value of the power drawn by the device under test; PMPP(t) instantaneous value of the MPP power provided theoretically by the PV simulator

3.6 conversion efficiency, energetic (conv)

ratio of the energy delivered by the device under test at the AC terminal within a defined

measuring period TM to the energy accepted by the device under test at the DC terminal:

where

PAC(t) instantaneous value of the delivered power at the AC terminal of the device under test;

PDC(t) instantaneous value of the accepted power at the DC terminal of the device under test

3.7 overall(total) efficiency

ratio of the energy delivered by the device under test at the AC terminals within a defined

measuring period TM to the energy provided theoretically by the PV simulator:

3.8 islanding

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.

3.9 intentional islanding

According to a pre-configured control strategy, a plan to place an island effect.

3.10 unintentional islanding

Unplanned and non-controlled island effects occurring.

3.11 anti-islanding

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Must not unplanned island effect Note1: while non-planned island effect occuring, due to system power state was unknown, it will

cause the following adverse effects:1 it is likely to endanger for staff and users of Power line maintenance.

Note2: power Interfere with the normal switch on Note3: Power do not control islands voltage and frequency, thereby equipments

of distributions and users will be damaged.

3.12 simulated utility

It is used for the test device of public power grid and its voltage and frequency are adjustable.

3.13 quality factor, Qf

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

LCRQf . (1)

Where: Qf is quality factor R is effective load resistance C is reactive load capacitance (including shunt capacitors) L is reactive load inductance

With C and L tuned to the power system fundamental frequency, Qf for the resonant circuit

drawing real power, P, reactive powers Qf, for inductive load and Qc for capacitive load, Qf can

be determined by

PPPQ qCqLf

where

P is real power

Qf is inductive load

Qc is capacitive load

Note: In a parallel resonant circuit qLqC PP

Let qqC PP

PPQ qf

3.14 resonant frequency

In a parallel resonant circuit, such as a load on a power system

LCf

2

1

Where

f is resonant frequency

L is inductive load

C is capacitive load

Note: while Parallel RLC circuit resonanting, capacitive and inductive reactive power are equal,

so parallel RLC resonant circuit is equivalent to a pure resistance.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

3.15 temporary

Used to quantify the duration of short-term changes, refers to the time range 3s ~ 1min.

4 Product Categories

4.1 Product type

4.1.1 According to grid-type

a. single-phase inverter

b. three-phase inverter

c. multi-phase inverter

4.1.2 According to the installation environment

a. indoor type

b. outdoor type

4.1.3 According grid-connected methods

a. reversible flow type

b. irreversible flow type

4.1.4 According to means of electrical isolation

a. isolated type

b. non-isolated type

4.1.5 According to voltage levels of connected grid

a. low voltage type

b. medium-high voltage type

4.1.6 According to emission limits

a. A-type inverter

A type inverter is not household inverter and inverter that not directly connected to the residential

facilities for low-voltage supply network. Sales of this type of inverters should not be limited. But

the following contents should be included in the operation instruction: Warning: This is an A-type

inverter product. It may cause radio interference in home environment. At this point, the user may

need additional measures.

b. B-type inverter

B-type inverter apply to all occasions, including home environment as well as all facilities which

directly connect to residential low-voltage power supply network.

4.2 Output power Characteristics

Rating values of inverter output power is priority to the following values(units kw).

4.2.1 Single-phase inverter module

CGC/GF004:2011(CNCA/CTS 0004-2009A)

0.5; 1.5; 2.5; 3; 5; 6; 7; 8; 9.

4.2.2 Three-phase inverter module

10; 30; 50; 100; 250; 500; 1000.

5 Technical requirements

5.1 Use conditions

Unless otherwise agreed upon by the manufacturer/suppier and purchaser, inverter should comply

prescribed performance requirements in 5.1.1 ~ 5.1.2 in this specification. For the terms of the

agreement, the test should be performed in accordance with the terms.

5.1.1 Environmental conditions of normal use

a. Temperature: Indoor type is -20 ~ +40 , outdoor type is -25 ~ +60 (no direct

sunlight); relative humidity 90%, non-condensing;

b. Altitude is not more than 1000m; when altitude> 1000m, inverter should be derating used

according to the reqirement of GB / T 3859.2;

c. No severe vibration impact, the vertical gradient 5 ;

d. No conductive explosive dust, corrosion of metals and destruction of insulating gases and steam

exist in the working environment.

5.1.2 Power conditions of normal use

a. Absence of other provisions, inverter should be able to run in following grid conditions

Utility grid harmonic voltage should not exceed the limits in Chapter 4 of GB / T 14549. Total

harmonic voltage distortion5%. Odd harmonic voltage distortion4%. Even harmonic voltage

distortion2%.

b. Three-phase inverter AC output voltage unbalance should not exceed GB / T 15543 specified

value, allowing a value of 2%, short-term should not exceed 4%.

c. For AC output voltage of 20kV or less, three-phase voltage Tolerance is 10% of the rated

voltage, 220V single-phase voltage Tolerance is +10%, -15% of rated voltage. Other cases, Power

Grid Voltage Tolerance should conform to GB / T 12325.

d. Power Grid Frequency Tolerance should conform to GB / T 15945,which is no more than

0.5Hz.

5.1.3 Special conditions

If the inverter is not used in the conditions of 5.1.1 and 5.1.2, users should reach agreement with

the suppliers.

5.2 Quality of the body and structure

Inverter structure and manufacturing quality of cabinet itself, the main circuit connection,

installations of secondary lines and electrical components shall meet the following requirements.

a. The components of rack assembly should be consistent with the technical requirements.

b. Paint plating should be firm, smooth, non-peeling,rust and cracking phenomena and so on.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

c. Rack panels to be flat, text and symbols to be clear, clean, standardize and correct.

d. Signs and markings should be complete and clear.

e. A variety of switches should be easy to operate, flexible and reliable.

f. Cabinet should have the appropriate protective measures to prevent the operator from

contacting with the electrode part directly, including AC and DC connection terminals and the

electrode of various electrical components.

5.3 Performance indicators

5.3.1 Conversion efficiency

Maximum conversion efficiency of transformerless inverter should not be less than 96%.

Maximum conversion efficiency of transformer inverter should not be less than 94%.

Note: Maximum power point tracking efficiency (including static and dynamic) will also affect the inverter

effectively use electric energy geneated by photovoltaic power system. This need scientific test. Specific limits

based on actual test data will be further clear.

5.3.2 Grid-connected current harmonic

The PV system output should have low current-distortion levels to ensure that no adverse effects

are caused to other equipment connected to the utility system.

Total harmonic current distortion shall be less than 5 % at rated inverter output. Each individual

harmonic shall be limited to the percentages listed in Table 1 and 2. Under other loads, current of

the inverter into the power grid should not exceed the acceptable harmonic current rated inverter

output.

Table 1 Current distortion limits for odd harmonics

Odd harmonics Distortion limit

3 through 9 Less than 4.0 %

11 through 15 Less than 2.0 %

17 through 21 Less than 1.5 %

23 through 33 Less than 0.6 %

35 and above Less than 0.3%

Table 2 Current distortion limits for even harmonics

Even harmonics Distortion limit

2 through 10 Less than 1.0 %

12 through 16 Less than 0.5 %

18 through 22 Less than 0.375 %

24 through 34 Less than 0.15 %

36 and above Less than 0.075 %

Note: As the voltage distortion may lead to more severe current distortion, harmonic test may be

has some problems. Injected harmonic currents shall not include any harmonic currents caused by

harmonic voltage from grid not connected to the PV system. Tests meeting the above

requirements may be regarded as ok, no further tests.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

5.3.3 Power factor

The PV system shall have a power factor no less than 0.98(leading or lagging) when the output

active power is greater than 50 % of the rated inverter output power. Power factor should be no

less than 0.95(leading or lagging) when the output active power is between 20%~50%.

Average Power Factor(PF)is

2out

2out

out

QP

PPF

where

outP Total the inverter output active power

outQ Total the inverter output reactive power.

Note : Specially designed systems that provide reactive power compensation may operate outside

of this limit with utility approval.

5.3.4 Response to abnormal voltage

The inverter should work properly when the power grid voltage is in the following range. The

single-phase voltage (220V) deviation is between -15% and +10% of rated voltage and

three-phase voltage (380V) deviation is between -10% and +10% of rated voltage. The inverter of

other output voltage should be able to work properly in the corresponding allowable grid voltage

deviation according to GB / T 12325.

When the output voltage of inverter deviates outside the conditions specified in Table 3, the

photovoltaic system shall cease to energize the utility distribution system and send warning signal.

The respond time to abnormal voltage should comply with the requirements specified in Table 3.

Inverter should restart and operate normally after the grid voltage recovers to the allowable range.

This applies to any phase of a multiphase system.

Table 3 Response to abnormal voltage

Voltage a(at point of utility connection) Maximum trip time

V < 0.5 * Vnominal 0.1s

50 % Vnominal V < 85 % Vnominal 2.0s

110 % Vnominal < V < 135 % Vnominal 1.0s

135 % Vnominal V 0.05s a: Effective voltage

Note 1: Trip time refers to the time between the abnormal condition occurring and the inverter

ceasing to energize the utility line.

Note 2: When in the Table 3 the response time for abnormal voltage and other protection methods

conflict, give priority to other protection.

5.3.5 Response to abnormal frequency

When the grid frequency various, the inverter should comply with the requirments in Table 4.

When the inverter cease to energize the utility distribution system, it should restart and operate

normally after the grid frequency recovers to the allowable range.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Table 4 Response to abnormal frequency

Frequency range Inverter response

48Hz Inverter stops operating within 0.2 seconds

48-49.5Hz Inverter stops operating after 10 minutes

working

49.5-50.2Hz Inverter works normally

50.2-50.5Hz Inverter stops operating after 2 minutes

working, It is forbid to connect the grid

50.5Hz Inverter stops operating after 0.2 seconds

working, It is forbid to connect the grid

5.3.6 DC Component

When inverter operate at rated power connecting to the grid, DC component from grid feeded

inverter should not exceed 0.5% of output current rating of or 5mA, whichever is the larger value

should be.

5.3.7 Voltage unbalance degree

When inverter operate connecting to the grid (three phase output), three-phase voltage unbalance

of public connection point of inverter accessing to the grid does not exceed the limits specified in

GB / T 15543. Negative sequence voltage unbalance of common connection point should not

exceed 2%, short-term should not exceed 4%; the negative sequence voltage unbalance caused by

inverter does not exceed 1.3%, short-term not more than 2.6%.

5.3.8 Noise

While inputting rated voltage and the inverter is under full load operation , noise is measured by

the sound level meter at a distance of 1m in level position away from device. For the noise level is

greater than 80dB, conspicuous position of the inverter should affixed "hearing damage" warning

signs. The guidance should be given in the instructions to reduce hearing damage.

5.4 Electromagnetic Compatibility

5.4.1 Emission requirements

5.4.1.1 Conducted emission test

In the frequency range of 0.15 MHz to 30 MHz, the disturbance voltage limit of auxiliary power

supply port of A-type and B-type inverter is listed in table 5. The disturbance voltage of auxillary

power supply port should not exceed the value specified in table 5.

Table 5 In the frequency range of 0.15 MHz to 30 MHz, the disturbance voltage limits of

auxiliary power supply port for A-type and B-type inverter

Frequency Range

MHz Limit

dBV

CGC/GF004:2011(CNCA/CTS 0004-2009A)

A-type B-type quasi peak average value quasi peak average value

0.150.50 79 66 6656a 5646a

0.505.0 73 60 56 46 5.0 30.0 73 60 60 50

a Limit decreases with logarithm of the frequency.

5.4.1.2 Radiated Emission test

In the frequency range of 30MHz to 1000MHz, the radiated emission limit of A-type and B-type

inverter listed in table 6. The radiated emission should not exceed the value specified in table 6.

Table 6 In the frequency range of 30MHz to 1000MHz, the radiated emission limits of

A-type and B-type inverter

Frequency Range MHz

Quasi peak limit dB(V/m)

A-type, 10m test distance B-type, 10m test distance

30230 40 30 2301000 47 37

5.4.2 Immunity requirements

5.4.2.1 Electrostatic discharge (ESD) immunity test

Inverter should be subjected to class 3 at least in GB/T 17626.2-2006, and the test results should

meet the requirements of class b in GB/T 17626.2-2006.

5.4.2.2 Radiated radio-frequency electromagnetic field (RFEMS) immunity test

Inverter should be subjected to class 3 at least in GB/T 17626.3-2006, and the test results should

meet the requirements of class a in GB/T 17626.3-2006.

5.4.2.3 Electrical fast transient/burst (EFT) immunity test

Inverter should be subjected to class 2 at least in GB/T 17626.4-2008, and the test results should

meet the requirements of class a in GB/T 17626.4-2008.

5.4.2.4 Voltage fluctuations immunity test

Inverter should be subjected to class 2 at least in GB/T 17626.14-2005, and the test results should

meet the requirements of class a in GB/T 17626.14-2005.

5.4.2.5 Surge immunity test

The auxiliary power supply port of inverter should be subjected to 1.2/50s surge signal, line to

line1kV,line to earth2kV, and the test results should meet the requirements of class b in GB/T

17626.5-2008.

5.4.2.6 Conducted disturbances, induced by radio-frequency fields immunity test

Inverter should be subjected to class 3 at least in GB/T 17626.6-2008, and the test results should

CGC/GF004:2011(CNCA/CTS 0004-2009A)

meet the requirements of class a in GB/T 17626.6-2008.

5.4.2.7 Power frequency magnetic field immunity test

Power frequency magnetic field immunity should use GB / T 17626.8-2006 test level in the stable

and sustainable magnetic field (see Table 7), the inverter should be able to withstand the selected

level of power frequency electromagnetic field test in stable and continuous magnetic field.

Table 7 Magnetic field test levels

level magnetic field intensity

A/m

1 1

2 3

3 10

4 30

5 100

X1) Special

1) Open level, can be given in the product

specification.

For type-A inverter which expects to connect to the grid and the industrial working

environment, power frequency magnetic field immunity should use test level 4 of GB / T

17626.8-2006 in the stable and sustainable magnetic field. The inverter should be able to

withstand stable and sustainable power frequency magnetic field of selected test level.

For type-B inverter which expects to connect to commercial and light industrial environments,

power frequency magnetic field immunity should use test level 3 of GB / T 17626.8-2006 in the

stable and sustainable magnetic field. The inverter should be able to withstand stable and

sustainable power frequency magnetic field of selected test level.

5.4.2.8 Oscillatory waves immunity test

According to the working environment, inverter should be tested for the specified test level in

GB / T 17626.12 oscillatory wave immunity test. Test criterion should be made respectively

according to different working environment.

5.5 Protection functions

5.5.1 Power failure protection

5.5.1.1 Anti-islanding protection

The inverter should have the function of anti-islanding protection. The inverter must cease to

energize the utility line with warning signals within 2 s when the grid which inverter connected to

fails to power supply. Refer o Appendix B for anti-islanding protection scheme selection rule

5.5.1.2 Low voltage withstanding capability

The medium and high voltage inverters specifically applicable to large PV power stations shall

have certain withstanding capability to the voltage abnormality in order to avoid the disconnection

CGC/GF004:2011(CNCA/CTS 0004-2009A)

when the grid voltage is abnormal and thus brings about grid power unstability. When the voltage

at the POI is within the area of the voltage outline or above shown in Figure 1, the PV power

station must ensure the continuous interconnection operation; if the voltage at the POI is below the

voltage outline in the figure, the PV power station is allowed to stop the power feeding into the

grid line.

Figure 1 Low Voltage Withstanding Capability Requirement for Large and Medium PV Power

Station

UL0: the minimum voltage limit value in normal operation

UL1 : the lower voltage limit to be withstood

T1: the interconnection time necessary to be kept when the voltage falls to UL1

T2 : the interconnection time necessary to be kept when the voltage falls to UL0.

The determination of UL1, T1 and T2 shall consider such actual situations as protection and

reclosing action time, etc.

The actual limit should be in accordance with the technical specifications of relevant departments

in charge of grid access.

5.5.1.3 AC side short-circuit protection

The inverer should have the function of short-circuit protection. When output short-circuit was

detected, the inverter should cease to energize the gird. If twice of output short circuit protction is

detected in 1 minute, the inverter is forbidden to connected to the grid sautomatically

5.5.2 Prevention of anti-discharge protection

When the inverter DC side voltage is lower than the permitted work scope or inverter is turned off,

there should be no reverse current in the inverter DC side.

5.5.3 Reverse polarity protection

Voltage drop due to abnormal grid

PV power station may be cut away from the grid

PV power station must operate

in connection with grid

CGC/GF004:2011(CNCA/CTS 0004-2009A)

When the photovoltaic array in reverse polarity, the inverter should be protected from damage.

Polarity is received, the inverter should be able to work properly.

5.5.4 DC current overload protection

When the photovoltaic array output power exceeds allowed maximum DC input power of inverter,

the inverter should work in allowed maximum AC output power in limiting current automatically.

In the condition of 7 hours continuous operating or temperature exceeds the allowable value, the

inverter is permitted to cease to energise the grid. Normally, the inverter should be able to work

properly.

Note: overload protection of photovoltaic grid-connected inverter with maximum power point

tracking control is that working point deviate from maximum power point of photovoltaic array.

5.5.5 DC over voltage Protection

When the inverter DC input voltage is higher than the maximum DC Array allowable input

voltage, the inverter should not start or should stop working within 0.1s (running inverter) with

warning signals. After the DC side voltage recover to the allowable working voltage, the inverter

should start normally.

5.6 Array insulation resistance detection

5.6.1 Array insulation resistance detection for inverters for functionally grounded arrays

Inverters for use with ungrounded arrays shall have means to measure the DC insulation

resistance from the PV input (array) to ground before starting operation.If the insulation resistance

is less than R = (VMAX PV/30 mA) ohms, the inverter

a) For isolated inverters, shall indicate a fault (operation is

allowed); the fault indication shall be maintained until the array insulation resistance

has recovered to a value higher than the limit above;

b) For non-isolated inverters, or inverters with isolation not complying with the leakage

current limits in the minimum inverter isolation requirements, shall indicate

a fault, and shall not connect to the grid; the inverter may

continue to make the measurement, may stop indicating a fault and may connect to the

grid if the array insulation resistance has recovered to a value higher than the limit

above.

5.6.2 Array insulation resistance detection for inverters for functionally grounded arrays

Inverters that functionally ground the array through an intentional resistance integral to the

inverter, shall meet the requirements in a) and c), or b) and c) below:

a) The value of the total resistance, including the intentional resistance for array functional

grounding, the expected insulation resistance of the array to ground, and the resistance of

any other networks connected to ground (for example measurement networks) must not be

lower than R = (VMAX PV/30 mA) ohms. The expected insulation resistance of the array to

ground shall be calculated based on an array insulation resistance of 40 M per m2, with

CGC/GF004:2011(CNCA/CTS 0004-2009A)

the surface area of the panels either known, or calculated based on the inverter power

rating and the efficiency of the worst-case panels that the inverter is designed to be used

with.

b) As an alternative to a), or if a resistor value lower than in a) is used, the inverter shall

incorporate means to detect, during operation, if the total current through the resistor and

any networks (for example measurement networks) in parallel with it, exceeds the residual

current values and times in Table 8 and shall either disconnect the resistor or limit the

current by other means. If the inverter is a non-isolated inverter, or has isolation not

complying with the leakage current limits in the minimum inverter isolation requirements, it shall

also disconnect from thegrid.

c) The inverter shall have means to measure the DC insulation resistance from the PV input

to ground before starting operation.

5.7 Array residual current detection

5.7.1 General

In a non-isolated inverter, or an inverter with isolation that does not adequately limit the available

touch current, the connection of the mains to earth (ie the earthed neutral) provides a return path

for touch current if personnel inadvertently contact live parts of the array and earth at the same

time.

The requirements in this section provide additional protection against this shock hazard through

the application of 5.7.4 or 5.7.5, except neither is required where isolation is provided that limits

the available touch current to less than 30mA.

Ungrounded and grounded arrays can create a fire hazard if a ground fault occurs that allows

excessive current to flow on conductive parts or structures that are not intended to carry current.

The requirements in this section provide additional protection against this fire hazard by

application of 5.7.4 or 5.7.5, except neither is required where is provided that limits the

available current to less than

- 300mA for inverters with rated continuous output power 30kVA, or

- 10mA per kVA of rated continuous output power for inverters with rated continuous

output power rating > 30kVA

5.7.2 30mA touch current type test for isolated inverters

The inverter must connect and operate under REFERENCE TEST CONDITIONS, except that the

DC supply to the inverter must not have any connection to earth, and the mains supply to the

inverter must have one pole earthed. It is acceptable (and may be necessary) to defeat array

insulation resistance detection functions during this test. The touch current measurement circuit of

IEC 60990, Figure 4 is connected from each terminal of the array to ground, one at a time. The

resulting touch current is recorded and compared to the 30mA limit.

5.7.3 Fire hazard residual current type test for isolated inverters

CGC/GF004:2011(CNCA/CTS 0004-2009A)

The inverter must connect and operate under REFERENCE TEST CONDITIONS, except that the

DC supply to the inverter must not have any connection to earth, and the mains supply to the

inverter must have one pole earthed. It is acceptable (and may be necessary) to defeat array

insulation resistance detection functions during this test. An ammeter is connected from each

terminal of the array to ground, one at a time. The current is recorded and compared to the limit in

5.7.1.

5.7.4 Protection by application of RCDs

The requirement for additional protection in 4.201.3.1 can be met by provision of an RCD with a

residual current setting of 30mA, located between the inverter and the mains. When required by

Part 1, the RCD must be type B rather than type A or type AC. The RCD may be provided integral

to the inverter, or may be provided by the installer if details of the rating, type, and location for the

RCD are given in the installation instructions per 5.3.2.208.

5.7.5 Protection by residual current monitoring

The inverter shall provide residual current monitoring that functions whenever the inverter is

connected to the MAINS with the automatic disconnection means closed. The residual current

monitoring means shall measure the total (both a.c. and d.c. components) RMS current.

For different inverter types, array types, and inverter isolation levels, detection may be required

for excessive continuous residual current, excessive sudden changes in residual current, or both,

according to the following limits:

a) Continuous residual current: The inverter shall disconnect within 0.3 seconds and signal a fault

if the continuous residual current exceeds:

- 300mA for inverters with continuous output power rating _ 30kVA

- 10mA per kVA of rated continuous output power for inverters with continuous output power

rating > 30kVA

b) Sudden changes in residual current: The inverter shall disconnect from the MAINS within the

time specified in Table 8 if a sudden change in residual current is detected exceeding the value

in the table.

Table 8 Response time limits for sudden changes in residual current

Residual

current sudden change

Max time to inverter

disconnection from the

MAINS

30mA 0.3s

60mA 0.15s

150mA 0.04s

5.8 Communication

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Inverter should be set up local communication interface. Communication interface should be used

with fixed measures to protect effective connection between connecting table and equipment.

Communication port should have resistance to electromagnetic interference, and easy to form a

network.

5.9 Auto on / off

Inverter should be automatically startup and shutdown according to sunrise and sunset.

5.10 Soft-start

Inverter starts running, the output power should be slowly increasing, that is rate of change of the

output power should be adjustable. Output current has no impact.

5.11 Insulation resistance and dielectric strength test

5.11.1 Insulation resistance

The insulation resistance between input circuit to the ground, the output circuit to the ground of

inverter and input circuit and output circuit should not be less than 1M. Insulation resistance is

only reference for dielectic strength test.

5.11.2 Dielectric strength test

Inverter input circuit to ground, the output circuit to ground and input circuit to the output circuit

should withstand 50Hz sinusoidal AC voltage or equivalent DC voltage for 1 min. The

root-mean-square values of test voltage is listed in Table 4. In the test, no breakdown and arcing

shall occur. The leakage current

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Degrees of protection provided by enclosure of inverter should comply with the requirement of

GB 4208. Indoor-type inverter should not be less than IP20; outdoors-type should not be less than

IP54.

5.13 Environmental test requirements

5.13.1 Low-temperature starting test

Inverter should work normally after the test according to the requirement specified in 6.13.1.

5.13.2 High-temperature starting and operating test

Inverter should work normally after the test according to the requirement specified in 6.13.2.

5.13.3 Constant damp heat test

Inverter should work normally after the test according to the requirement specified in 6.13.3.

5.14 Power control and voltage regulation

5.14.1 Active power control

Inverters suitable for large and medium PV power stations shall have the capability of active

power regulation. The current produced in the process of power adjustment should not exceed 1.5

times of rated current

5.14.2 Voltage/Reactive power regulation

The power factor of the medium and high voltage inverters shall be adjustable in the scope of 0.98

(forward) ~ 0.98 (backward); in special circumstance, the power factor can be confirmed through

a negotiation with the power grid company. In the reactive output scope, the large and medium PV

power stations shall have the capability of regulating reactive output and participating in the

regulation of the grid voltage according to the voltage level at the POI, and its regulation mode,

reference voltage, voltage regulation difference ratio, etc shall be able to be set remotely by the

grid dispatching department.

5.15 Continuous operation test

No abnormity should occur when inverter opeating under the rated power for 72 hours .

5.16 Temperature rise test

5.16.1 General

This subclause specifies requirements intended to prevent hazards due to:

a)touchable parts exceeding safe temperatures; and

b)components, parts, insulation and plastic materials exceeding temperatures which may degrade

safety-related electrical, mechanical, or other properties during normal use over the expected life

of the equipment; and

c)structures and mounting surfaces exceeding temperatures which may degrade the materials over

the expected life of the equipment.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

5.16.2 Maximum temperatures

Materials and components shall be selected so that under the most severe rated operating

conditions, the temperatures do not exceed the temperature limits below. Compliance is verified

by measuring temperatures under each rated operating condition or mode of the inverter that could

affect the resulting temperatures. Tests of equipment rated for use in ambient temperatures up to

50 C may be conducted at any ambient temperature, in which case the difference between the

maximum rated ambient temperature and the actual test ambient is to be subtracted from or added

to (as appropriate) the measured temperatures for comparison to the limits specified below. The

difference between the maximum rated ambient temperature and the test ambient is to be

subtracted from or added to (as appropriate) the measured temperatures for comparison to the

limits specified below. During thermal testing within normal conditions protective devices other

than automatic output derating systems shall not operate. Temperatures are to be measured by

thermocouples:

a) For coils and their insulation systems, the temperature limits in Table 11 apply.

b) For other components the measured temperatures shall not exceed the lower of:

1) the limits in the applicable IEC component standards 2) the component or material manufacturers rated operating temperature 3) if neither of the above exists, temperature limits are given in Table 12.

Table 10 Total temperature limits for transformers, inductors, and other coils and their

insulation systems

Class of insulation

(see IEC 60085)

Limits for surface

mounted

Thermocouple

measurements

C

Limits for resistance method and

multiple embedded thermocouple

measurements

C

Class A(105C) 90C 95C

Class E(120C) 105C 110C

Class B(130C) 110C 120C

Class F(105C) 130C 140C

Class H(180C) 150C 160C

Class N(200C) 165C 175C

Class R(220C) 180C 190C

Class S(240C) 195C 205C

NOTE Surface mounted thermocouples are assumed to not be located on the hot-spot, but will

be typically attached to the core, coil, and insulation that is accessible on a completed part.

Multiple embedded thermocouples, where the thermocouples are attached during winding of the

part, are more likely to record hot-spot temperatures. The resistance method gives an average

temperature for the specific winding whose resistance rise was measured.

Table 11 Total temperature limits for materials and components where manufacturers

ratings and component standards do not exist

Materials and components Limit C

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Capacitors - electrolytic types 75C

Capacitors - other than electrolytic types 100C

Wiring terminals for external connections [1] 70C

Any point on or within a wiring compartment

which external conductors are able to contact [1] 70C

Insulated conductors internal to the inverter rated temperature

Fuses 100C

Printed circuit boards 115C

Insulating materials 100C

Connection between semiconductor

components and conductor of main circuit

Bare copper75

Tin-plated85

Silver-plated100

[1] Wiring point measured at connecting terminal and in connecting box

Table 12 Total touch temperature limits for accessible surfaces

Part

Limit

C

Metal Glass,

porcelain, and

other vitreous

materiala

Plastic and

rubbera

User operated devices (knobs, handles, switches,

displays, etc.) which are continuously held in normal

use

65C 75C 80C

User operated devices (knobs, handles, switches,

displays, etc.) which are held for short periods only in

normal use

70C 75C 90C

Enclosure parts accessible to user by casual contact. 80C 90C 100C

a Nonmetallic materials shall not be used above their temperature ratings.

For the operating handle touched only when device opened, as they do not always operate, it is allowable a

higher temperature.

6 Test methods

The following test methods are explained based on single-phase grid-connected inverters, for

three-phase inverters they can be referenced.

Note : The minimum allowable output power is used if it is larger than 5% of the rated AC output

power.

6.1 Test environmental conditions

Unless otherwise specified, measurements and tests are performed under the following

CGC/GF004:2011(CNCA/CTS 0004-2009A)

conditions:

a Temperature: 15~35;

b Relative humidity: 45%~75%;

c Air pressure: 86kPa~106kPa.

6.2 Inspecting the quality of main body and structure

Perform visual inspection and operation tests pursuant to provisions in 5.2.

6.3 Performance index test

6.3.1 Performance index test platform

Figure 2 shows reference circuit of the performance index test for the inverters, some of the

protection function can also be referenced. The test requirements are as follow:

a) The simulation AC grid should be compliant with the provisions in section 5.1.2, and the

capacity should be larger than 2 times of the rated power of the inverter to be measured

or satisfy relevant testing requirements

b) The DC input source of the inverter to be measured is better to be a PV array or a PV

array simulator. The DC input source should at least be able to provide 1.5 times the

maximum DC input power of the inverter to be measured, and the output voltage of the

DC input source should match the operation range of the DC input voltage of the inverter

to be measured; the voltage fluctuation should not exceed 5% during the test;

c) If the inverter to be measured has specified DC input source, but this input source is not

able to provide the inverter output power specified for the test, then the test should be

done within the range that the input source is able to supply.

DC input source

Inverter under test

Power quality analyzer

Grid simulator

Fig.2 Performance index test platform

Note 1: K1 is the grid-side disconnecting switch of the inverter.

6.3.2 Conversion efficiency test

Test circuit should conform to the relevant criterion in GB/T 20514-2006. The whole efficiency

test should include:

CGC/GF004:2011(CNCA/CTS 0004-2009A)

6.3.2.1 Maximum Conversion efficiency

According to the design of the inverter, the maximum conversion efficiency test result should

conform to the provisions in section 5.3.1.

Note1: If the inverters control connectors are powered in other way, a power consumption should

be noted in the report, when the inverter reaches its maximum efficiency.

Note2: In the process of testing, MPPT function should be shut down.

6.3.2.2 Conversion Efficiency curve

Measure at the load of 5%, 10%, 15%, 20%, 5%, 30%, 50%, 75%, 100% maximum conversion

efficiency appeared load point and inverters conversion efficiency at its maximum output power,

and show these results in the report in the form of curve diagram. Also it should show the values

of voltage and current at each load point.

The test should also provide the inverter efficiency curve measured under high temperature

conditions specified in section 6.13.1. Test results should be shown in the report.

6.3.3 Grid-connected current harmonic test

Measure testing point should be chosen at the AC grid side where inverter is connected to, run the

test when the output of the inverter is the rated power. Measure the total current harmonic

distortion rate and the both harmonic current ratios using a power quality analyzer. The results

should be compliant with the provisions in section 5.3.2. Meanwhile, measure the each current

harmonic distortion value at the load of 30% 50% 70%, that value should not exceed the each

current harmonic distortion value at the rating load.

6.3.4 Power factor measurement

The measured power factor (PF) using a power quality analyzer or a power factor meter should be

compliant to the provisions in section 5.3.3.

6.3.5 Grid voltage response test

This test should run at the inverters minimum working power, set the grid simulators output

voltage value, it reacts or reacting time should be compliant to the provisions in section 5.3.4.

6.3.6 Grid frequency response test

This test should run at the inverters minimum working power, set the grid simulators output

voltage frequency, it reacts or reacting time should be compliant to the provisions in section 5.3.5.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

6.3.7 DC component test

When the inverter operates at the nominal load, then measure the DC component in the AC

current, the results should be compliant to the provisions in section 5.3.6.

6.3.8 Voltage unbalance test

When the inverter operates at the nominal load, then measure the three-phase voltage unbalance at

the point of common coupling, the results should be compliant to the provisions in section 5.3.7.

6.3.9 Noise test

Inverter works in the harshest condition, in the direction where noise is highest, measure the

noise level using noise meter at 1m away from the inverter. For the noise meter, it should use the

A-weight pattern.

When testing, it should be sure that the difference between real test noise and background

noise is larger than 3dB, or else steps should be taken, to make test environment meet the

requirement, if the test result and background noise s difference is larger than 10dB, test result

does not need to be amended. When the difference between noise and background noise is in the

range of 3dB to 10dB, amending the result according to the table 13

Table 13 Table of measurement value correction for background noise

Difference value(dB) 3 45 610

Correction value(dB) -3 -2 -1

6.4 EMC test

For all the tests, the inverter should be configured according to the actual installation conditions if

possible, including the relevant wiring and agreed termipoints. All components of the inverter

should be incorperated into the enclosure with all the covers and panels installed, and with proper

grounding, unless otherwise agreed with the user.

6.4.1 Emission test

6.4.1.1 Conductive emission test

The test arrangement and measurement principles should conform to the provisions in appendix A

of GB 7260.2-2009. The results should be compliant to the provisions in section 5.4.1.1.

6.4.1.2 Radiation emission test

The test arrangement and measurement principles should conform to the provisions in appendix A

of GB 7260.2-2009. The results should be compliant to the provisions in section 5.4.1.2

6.4.2 Immunity test

CGC/GF004:2011(CNCA/CTS 0004-2009A)

6.4.2.1 Electrostatic discharge immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.2-2006. The test should be done through single-discharge, apply ten times of

single-discharge at the pre-selected point.

6.4.2.2 RF electromagnetic field radiation immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.3-2006.

6.4.2.3 Electrical fast transient/burst immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.4-2008.

6.4.2.4 Voltage fluctuating immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.14-2005.

6.4.2.5 Surge (impact) immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.5-2008.

6.4.2.6 Test for immunity to conducted disturbances induced by RF field

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.6-2008.

6.4.2.7 Power frequency magnetic field immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.8-2006.

6.4.2.8 Oscillatory waves immunity test

The test arrangement and measurement principles should conform to the provisions in GB/T

17626.12-1998.

6.5 Protection functions tests

6.5.1 Grid fault protection test

6.5.1.1 Anti islanding protection test

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Fig.3 Anti-islanding protection test platform

DC input source

Inverter under test

Digital oscilloscope

Grid

Figure 3 shows the anti-islanding protection test platform, where K1 is the grid side

seperation switch of the measured inverter and K2 is the load separation switch. The load is

porvided by a variable RLC resonance circuit. The resonance frequency equals to the rated

frequency (50/60Hz) of the measured inverter, and the power consumption equals to the output

active power of the measured inverter. The test should be done under the conditions specified in

table 14.

Note: Due to the uncertainty of the absorption of active and reactive power by the grid from the

inverter, for this test it is more convincible to use actual grid than simulation grid.

Tab.14 Test conditions for anti-islanding protection

Condition Output power PEUT of

the measured inverter

Input voltage of the

measured inverter

Trip set value of the

measured inverter

A 100% the rated AC

output power

> 90% the range of the DC

input voltage

The voltage and

frequency trip values

specified by the

manufacturer

B

(50~66)% the rated AC

output power

50%10% the the range of

the DC input voltage

The voltage and

frequency trip values are

set as the rated values

C (25~33)% the rated AC

output power

CGC/GF004:2011(CNCA/CTS 0004-2009A)

a Close K1 and disconnect K2 to start the inverter. Let the output power PEUT of the

inverter equals to the rated AC output power and measure the output reactive power

QEUT of the inverter;

b Stop the inverter and disconnect K1;

c Adjust the RLC circuit so that Qf=1.00.05 following the procedures bellow;

The inductive reactive power of the RLC circuit can be expressed as:

QL=Qf*PEUT=1.0*PEUT;

Connect in the inductance L so that the reactive power consumption equals to QL;

Incorporate capacitor C so that the capacitive reactive power consumption can be

expressed as: QC+QL=- QEUT;

Finally incorporate the inductance R so that the active power consumption equals to

PEUT.

d Close K2 to connect it into the RLC circuit and close K1to start the inverter. Make sure

that the output power is compliant with the provisions in step a). Adjust R, L and C until

the fundamental-frequency current is less than 1% the rated output current of the inverter

at steady-state.

e Disconnect K1 and record the time period from when K1 is connected to when the output

current of the inverter decreases to and maintains 1% the rated output current;

f Adjust the active load (resistor R) and any reactive load (L or C) to achieve the situation

that the load indicated by the parameters in the brackets in table 16 doesnt match. The

parameters in table 15 are the deviations in percentage; the signs indicate the direction of

the active power flow and reactive power flow through switch K1 in figure 3. The

positive sign means that the power flow is from the inverter to the grid. The time

between when K1 is disconnected and when the output current of the inverter decreases

to and maintains 1% the rated output current. If any of the recorded time exceeds the

recorded time in step e), the parameters not in the brackets in table 15 should also be

tested;

g For test condition B and C, adjust any reactive load (L or C) so that it varies by 1% each

time according to table 17. The parameters in table 17 indicate the direction of the active

power flow and reactive power flow through switch K1 in figure 3. The positive sign

means that the power flow is from the inverter to the grid.The time between when K1 is

disconnected and when the output current of the inverter decreases to and maintains 1%

the rated output current. If the recorded time is increasing, the adjustment range should

be expanded by 1% step continuously until when the recorded time is decreasing.

h The recorded time in the above steps should be compliant with the provisions in section

5.5.1.1, or else the test is deemed to fail.

Tab.15 Load non-matching situations under test condition A

Deviation percentage (%) between the active and reactive power consumption of the load

-10+10 -5+10 0+10 +5+10 +10+10

-10+5 (-5+5) (0+5) (+5+5) +10+5

-100 (-50) 00 (+50) +100

-10-5 (-5-5) (0-5) (+5-5) +10-5

CGC/GF004:2011(CNCA/CTS 0004-2009A)

-10-10 -5-10 0-10 +5-10 +10-10

Tab.16 Load non-matching situations under test condition B and C

Deviation percentage (%) between the active and reactive power consumption of the load

0-5

0-4

0-3

0-2

0-1

01

02

03

04

05

6.5.1.2 Low voltage ride-through test

Figure 4 shows the Low voltage ride-through test platform, Medium or High Voltage type inverter

or the inverter which has the Low voltage ride-through function; their Low voltage ride-through

function should be compliant with the provisions in section 5.5.1.2.

Figure 4 Low voltage ride-through test platform

DC input source

Inverter under test

Oscilloscope

Low voltage ride through simulator

Grid

6.5.1.3 Output short-circuit protection test

The inverter should be able to protect itself when it is shorted. For three-phase inverters,

shorts are conducted between phase to phase, phase to neutral line, and phase to ground

respectively. For inverters with isolation transformers, shorts should be conducted at the primary

CGC/GF004:2011(CNCA/CTS 0004-2009A)

side and secondary side of the transformer respectively.

6.5.2 Anti reverse discharge protection test

There should be no reverse current at the DC side of the inverter when the DC side voltage of

the inverter is lower than the allowable operation range or the inverter is in power-off status.

6.5.3 Reverse polarity protection test

Wire up as shown in figure 2, when using a PV array simulator, adjust the simulator so that

the output voltage reaches the maximum rated input voltage of the inverter and the output current

should not be larger than 1.5 times the rated input current of the inverter.

Reverse the PV array or the PV array simulator, the inverter should be able to conduct

automatic protection; connect PV array correctly after 1min, the inverter should be able to operate

normally.

6.5.4 DC Overload protection test

Adjust the DC input source so that the output power exceeds the allowable maximum DC

input power of the inverter, and the operation status of the inverter should be compliant with the

provisions in 5.5.4.

6.5.5 DC over-voltage protection

Adjust the voltage of DC input source until the DC side input voltage deviates from the range

of the allowable DC input voltage of the inverter, and the operation status of the inverter should be

compliant with the provisions in 5.5.5.

6.6 PV array insulation resistance test

Connect inverter to the testing circuit loop, connect a less than Table 8 in 5.6 resistance to the

inverter input ports, the inverter should be compliant with the provisions in 5.6.

6.7 Residual current testing method

6.7.1 Continuous residual current testing method

Inverter operates at rated load in the harshed working condition, and DC side does not connect to

the ground, AC output side has one pole connect to the ground. PV array insulation resistance

monitoring function can be shut down. Connect adjustable resistance between DC input and

ground. The initial value of the resistance should be set making initial residual current under the

5.7.1 a) limitation. Then gradually reduce the resistance, record the current when the residual

current protection device reactive. Repeat this test for 5 times, all the test results should not either

exceed the limitation in 5.7.1 a) or disconnect from the AC grid in 0.3s.

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Note: If equipped with multiple inputs with same circuit principle and possible test result, there is

no need to test one by one.

6.7.2 On fire residual current testing method

Inverter works under the harshed condition, and the DC side does not connect to the ground, AC

output side has one pole connect to the ground. PV array insulation resistance monitoring function

can be shut down. Use a current meter to measure the residual current between every PV array

port and ground.

6.7.3 Residual current sudden change testing method

Inverter operates at rated load. Connect a resistance between DC input and ground, this resistance

can be controlled by a breaker. Adjust this resistance to generate exact 30mA, 60mA, 150mA

residual current between the input port and ground, the inverter disconnecting time from the AC

grid should not exceed the limitation listed in Table 8 in 5.7.1 b).

Note: If equipped with multiple inputs with same circuit principle and possible test result, there is

no need to test one by one.

6.8 Communication interface test

Check the communication ports are stable or not. Install the communication software on site,

check if the communication of the inverter is normal.

6.9 Automatic power on/off test

Simulate the sunlight irradiation conditions through changing the input DC voltage of the inverter,

and the inverter should be able to power on/off pursuant to the provisions in section 5.9.

Follow these specific procedures to do: wire up as shown in figure 2, adjust the DC input source

so that the DC side voltage increases from a voltage that is less than the lower limit of the

allowable DC voltage of the inverter. When the DC side voltage is larger than the lower limit of

the allowable range, the inverter should be able to power on automatically; adjust the DC input

source so that the DC side voltage decreases to the upper limit of the allowable DC voltage of the

inverter, and when the inverter should be able to power/off automatically.

6.10 Soft start test

When the inverter starts to work, use the power analyzer or other power monitoring

equipments to monitor the output power of the inverter, the change of the power should be

compliant with the provisions in 5.10.

6.11 Insulation voltage strength

6.11.1 Insulation resistance measurement

Measure the insulation resistance value of the inverter between the input circuit and ground,

CGC/GF004:2011(CNCA/CTS 0004-2009A)

output circuit and ground, and the input circuit and the output circuit using a megohmmeter or an

insulation resistance tester under 1000V test voltage. The results should be compliant with the

provisions in section 5.11.1. The insulation strength test can only be conducted after the

measurement of insulation resistance passes.

6.11.2 Insulation strength measurement

Measure the inverter between the input circuit and ground, output circuit and ground, and the

input circuit and the output circuit using a voltage-withstanding tester according to the 5.9.2. The

results should be compliant with the provisions in section 5.11.2.

Note: when testing the insulation resistance and the insulation strength, low voltage control circuit

can be removed.

6.12 Degrees of protection provided by enclosure

Conduct the test pursuant to GB 4208-2008, the enclosure ingress protection of the inverters

should be compliant to the provisions in section 5.12.

6.13 Environmental test

6.13.1 Low-temperature start test

Conduct the test pursuant to Test A in GB/T 2423.1. Keep the product under (-203)

(indoor type) or (-253) (outdoor type) test temperature conditions without the packaging stuff

for 2 hours, the inverter should be able to start normally

6.13.2 High-temperature start and operation test

Conduct the test pursuant to Test B in GB/T 2423.2. Keep the product under (402)

(indoor type) or (602) (outdoor type) test temperature conditions without the packaging stuff

for 2 hours, the inverter should be able to start normally; then power up and apply rated load for 2

hours and let the inverter recover under standard atmosphere conditions for 2 hours, the inverter

should be able to operate normally.

6.13.3 Constant damp heat test

Conduct the test pursuant to GB/T 2423.3. Keep the product under (402) (indoor type) or

(602) (outdoor type) test temperature and (903)% constant humidity and temperature

conditions without the packaging stuff and without power on for 48 hours; then take out the

inverter and let it recover under normal environmental conditions for 2 hours, the inverter should

be able to operate normally.

6.14 Power control and voltage adjustment test

6.14.1 Active power control test

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Send active power control signals (including the maximum output power and power variation

rate etc.) to the inverter through simulating using a PC, the inverter should be able to receive and

execute the signals. Inverter current should not exceed the 1.5 times impulse current when inverter

changing at the maximum power change rate

6.14.2 Voltage/reactive power adjustment test

Send reactive power control signals (including the adjust method, reference voltage and voltage

adjustment ratio etc.) to the inverter through simulating using a PC, the inverter output reactive

power should be within the specified range and the inverter should be able to adjust the reactive

output based on the voltage level at the grid-connection point.

6.15 Continuous operation test

Wire as shown in figure 2 and put the inverter in operation under rated power, observe the

working condition of the inverter, no abnormal situation should occur within 72 hours.

6.16 Temperature rise test

Temperature meters, thermocouples, thermistor components, or other effective methods can be

used to measure the temperature.

The test should last for a period long enough so that the temperatures at all positions of the

inverter achieve stable values of thermal balance. There should be no action taken in the process

of testing, such as open the front cover of the cabinet, which will influence the normal heat

dissipation mode. The temperature rise is considered stable when the temperature variation is

slower than 1/half an hour.

In the test, difference correction method can be used. That is measure the temperature rise in the

normal condition, and add the temperature rise to the highest allowable working temperature,

compare the result with the figure in 5.16.

7 Inspection rules

7.1 Inspection categories

Factory inspection and product testing sub-type testing, test items shown in Table 5

No.

Test item

Type test

Factory

inspection Test Method

1 Quality of the body and structure

inspection

2 Conversion efficiency test

3 Grid-connected current harmonic test

CGC/GF004:2011(CNCA/CTS 0004-2009A)

No.

Test item

Type test

Factory

inspection Test Method

4 Power factor test

5 Response to abnormal voltage test

6 Response to abnormal frequency test

7 DC component test

8 Voltage unbalance degree test

9 Noise test

10 Conducted emission test

11 Radiated emission test

12 Electrostatic discharge immunity test

13 Radiated, radio-frequency

electromagnetic field immunity test

14 Electrical fast transient burst immunity

test

15 Voltage fluctuation immunity test

16 Surge immunity test

17 Conducted disturbance, induced by

radio-frequency fields immunity Test

18 Power frequency magnetic field

immunity test

19 Oscillatory waves immunity test

20 Anti-island protection test

21 Low voltage withstanding capability test

22 AC side short-circuit protection test

23 Prevention of anti-discharge protection

test

24 Reverse polarity protection test

25 DC current overload protection test

26 DC over voltage test

27 Communication test

28 Auto on / off test

29 Soft-start test

30 Insulation resistance test

31 Dielectric strength test

32 Degrees of protection provided by

enclosure

33 Low-temperature starting test

34 High-temperature starting and operating

test

35 Constant damp heat test

36 Active power control test

37 Voltage/Reactive power regulation test

CGC/GF004:2011(CNCA/CTS 0004-2009A)

No.

Test item

Type test

Factory

inspection Test Method

38 Temperature rise test

39 Array insulation resistance detection test

40 Array residual current detection test

41 Continuous operation test

7.2 Factory Inspection

Each inverter factory inspection should be carried out. One in Taichung and a performance does

not meet the requirements, that is, unqualified to be reworked re-examination, re-examination is

still unsatisfactory, for the test failed. After passing inspection, complete inspection records and

issue a certificate before being manufactured.

7.3 Type test

7.3.1 When there is one of the following conditions, type of inspection should be carried out

a) Identification of new products

b) After official production, The structure, the material, the craft have change greatly,

affects when sufficiently the product performance

c) mass-produced products, once type tests every three years

d) Product discontinued two years after the resumption of production

e) State Administration of Quality Supervision agencies to conduct type test requirements

7.3.2 Methods of sampling and determine the rules

Samples for type testing, factory inspection shall be qualified through the random sample of

products. The quantity is two units, according to GB / T 2829 standard requirement. Determine the

level of the sample using a sampling plan for the , the product quality to unqualified number

indicates a failure to take quality of RQL = 120

8 Logo, Packaging, Transportation, Storage

8.1 Logo

8.1.1 Product logo

The inverter nameplate should be place on the appropriate place. The nameplate as follows

a) Product name

b) Product model

c) Technical parameter

Fixed AC output power(kW)

Maximal contrastive efficiency(%)

DC entering voltage range(V)

Nominal AC voltage range(V)

CGC/GF004:2011(CNCA/CTS 0004-2009A)

Protection Level

d) serial number

e) the date of manufacture

f) manufacturer name

8.1.2 Packaging marks

The inverter should have the consignor marks, packaging and storage marks and warning marks

According to the relevant provisions of GB / T 191

8.2 Packaging

8.2.1 The technical documentation accompanying the product

a) Installation Manual

b) Instruction of the product

c) Technical Specifications and parameters

d) Product quality certification

e) Warranty Card

f) The views of users questionnaire;

Note: Product Technical Data Sheet Reference Appendix A.

8.2.2 Product Packaging

Product packaging should conform to the relevant provisions of GB / T 3873

8.3 Transport

The inverter should not have the strenuous vibration, attack and to put upside down in the

transportation process,

8.4 Storage

Before the product use, should place in the original package boxStored in the air circulation, the

surrounding environment of not less than -40 , relative humidity of not more than 90%,

non-harmful gases and flammable, explosive materials, and corrosive materials in the warehouse

And should not be a strong mechanical vibration, shock and strong magnetic field.

CGC/GF001:2010CNCA/CTS 0004-2009

Appendix A

(Informative appendix)

Table A: Technical parameter table of grid-connected PV inverter

Manufacturers

Model

DC input

Rated maximum Photovoltaic array

power(kWp)

Maximum DC input power(kW)

Maximum array open-circuit voltage(V)

Maximum array input current (A)

DC input voltage range(V)

MPPT range(V)

AC output

Rated AC Output power(kW)

maximum AC Output power(kW)

Operating voltage range (V%)

Operating Frequency Range(Hz%)

Maximum inverter efficiency(%)

Efficiency of 25%,50%,100% of rated

load

Power factor

Total harmonic current distortion(%) Power consumption at night(W)

Noisy(dB)

Protection Function

Over / under voltage protection(yes/no)

Over/under frequency protection(yes/no)

Islanding protection(yes/no)

Over current Protection(yes/no)

Prevention of Anti-discharge protection

test(yes/no)

Reverse polarit protection(yes/no)

Overload Protection(yes/no)

Safe requirements

insulation resistance

insulation intension

shell protection grade

communication interface

Size

Length/Width/Height(mm)

CGC/GF001:2010CNCA/CTS 0004-2009

Weight (Kg)

Documentation requirements

Product instruction(yes/no)

User manual(yes/no)

Product qualification certificate(yes/no)

Warranty card(yes/no)

CGC/GF001:2010CNCA/CTS 0004-2009

Appendix B

(Informative appendix)

Select of anti-islanding protection scheme

Anti-islanding protection schemes of grid-connected PV inverter are active and passive.

Passive scheme is made by measuring AC output voltage or frequency of inverter. Because of the

shortcoming of passive scheme, active scheme is made to up to safety standards of anti-islanding

protection. Active scheme is made by inducting deliberately disturbance signal to monitor change

of voltage, frequency and impedance to determine the grid deposit.

Active scheme of anti-islanding protection is including change of impedance caused by

frequ