Photovoltaic grid-connected inverter technical specification (NB/T 32004-2013)

1 Scope

This standard specifies the product types, technical requirements, and test methods of inverters used in photovoltaic (Pv) grid-tied systems.

This standard is applicable to photovoltaic grid-connected inverters whose voltage is not more than 1500V DC and whose AC output voltage does not exceed 1000V.

2 normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document.

For undated references, the latest version (including all amendments) applies to this document.

GB/T 1408.1-2006 Test methods for electrical strength of insulating materials - Part 1: Test at frequency lowers (EEC 60243-1:1998, IDT)

GB/T 2423.1-2008 Environmental testing for electric and electronic products Part 2: Test methods Test A: Low temperature (IEC 60068-2-1:2007, IDT)

GB/T 2423.2-2008 Environmental testing for electric and electronic products Part 2: Test methods Test B: High temperature (IEC 60068-2-2:2007, IDT)

GB/T 2423.3-2006 Environmental testing for electric and electronic products Part 2: Test methods Test Cab: Constant moisture heat test (IEC 60068-2-78:2001, IDT)

GB/T 2423.4-2008 Environmental testing for electric and electronic products Part 2: Test methods Test Db: Alternating heat (12h + 12h cycle) U EC 60068-2-30:2005, IDT)

GB/T 2423.10-2008 Environmental testing for electric and electronic products Part 2: Test methods Test Fc: Vibration (Sine) QEC 60068-2-6:1995, IDT)

GB/T 2828.1-2012 Count sampling inspection procedures Part 1: Lot-by-batch sampling plans searched according to receiving quality (AQL) (ISO 2859-1:1999, IDT)

GB/T 3805-2008 Extra Low Voltage (ELV) Limits

GB/T 4207 solid insulation material resistance to tracking index and comparison of tracking index (IEC 60112, IDT)

GB 4208-2008 Enclosure Protection Level (IP Code) UEC 60529:2001, IDT)

GB 4824-2004 Industrial, scientific and medical (ISM) radio frequency equipment electromagnetic disturbance characteristics limit value and measurement method (CISPR 11:2003, IDT)

GB/T 5169.10-2006 Fire hazard testing for electric and electronic products - Part 10: Glow/hot wire basic test methods - Glow-wire apparatus and general test method (IEC 60659-2-10:2000, IDT)

GB/T 5169.11-2006 Fire hazard testing for electric and electronic products - Part 11: Glow/hot wire basic test methods Glow-wire flammability test method for finished products (IEC 60695-2-11:2000, IDT)

GB/T 5169.17-2008 Fire hazard testing for electric and electronic products Part 17: Test flame 500W flame test method (IEC 60695-11-20:2003, IDT)

GB/T 5465.2-2008 Graphical symbols for use in electrical equipment - Part 2: Graphical symbols (IEC 60417 DB:2007, IDT)

GB/T 12113-2003 Measurement methods for contact current and protective conductor current (IEC 60990:1999, IDT)

GB/T 14549-1993 Power Quality Public Power Harmonics

GB/T 15543-2008 Three-phase voltage imbalance in power quality

GB 16895.3-2004 Electrical installations of buildings - Part 5-54: Selection and installation of electrical equipment - Grounding arrangements, protective conductors and protective conductors (IEC 60364-5-54:2002, IDT)

GB/T 16895.10-2010 Low-voltage electrical apparatus - Part 4-44: Protection against voltage disturbances and electromagnetic harassment (IEC 60364-4-44:2007, IDT)

GB/T 16935.1-2008 Insulation coordination for equipment in low-voltage systems Part 1: Principles, requirements and tests (IEC 60664-1:2007, IDT)

GB 17625.2-2007 Limits for electromagnetic compatibility (IEC 61000-3-3:2005), Limits for voltage variations, voltage fluctuations and flicker in public low-voltage supply systems for equipment with a rated current of less than or equal to 16 A per phase and unconditional access IDT)

GB/T 17626.2-2006 Electromagnetic compatibility Testing and measurement techniques Electrostatic discharge immunity test (IEC 61000-4-2: 2001, IDT)

GB/T 17626.3-2006 Electromagnetic compatibility test and measurement technology Radio frequency electromagnetic field radiation immunity test (IEC 61000-4-3:2002, IDT)

GB/T 17626.4-2008 Electromagnetic compatibility Testing and measurement techniques Electrical fast transient burst immunity test (IEC 61000-4-4:2004, IDT)

GB/T 17626.5-2008 Electromagnetic compatibility Testing and measurement techniques Surge (impact) immunity test (IEC 61000-4-5:2005, IDT)

GB/T 17626.6-2008 Electromagnetic compatibility Testing and measurement techniques Conducted disturbance immunity of radio frequency fields (IEC 61000-4-6:2006, IDT)

GB/T 17626.8-2006 Electromagnetic Compatibility Testing and Measurement Technology Power Frequency Magnetic Field Immunity Test (IEC 61000-4-8:2001, IDT)

GB/T 17626.11-2008 Electromagnetic compatibility Testing and measurement techniques Voltage dips, short interruptions and voltage variations immunity test (IEC 61000-4-11:2004, IDT)

GB/T 17626.12-1998 Electromagnetic compatibility test and measurement techniques Oscillatory wave immunity test (IEC 61000-4-12:1995, IDT)

GB/T 17626.14-2005 Electromagnetic compatibility test and measurement techniques Voltage fluctuation immunity test (IEC 61000-4-14:2002, IDT)

GB/T 17627.2-1998 High-voltage test techniques for low-voltage electrical equipment Part 2: Measurement systems and test equipment (IEC 1180-2:1994, EQV)

GB/T 18479-2001 Overview and guidance for ground-use photovoltaic (Pv) power generation systems (IEC 61277:1995, IDT)

GB/T 19939-2005 Photovoltaic system grid connection technical requirements

GB/T 25919.1-2010 Modbus test specification - Part 1: Specification for Modbus serial link conformance testing

GB/T 25919.2-2010 Modbus test specification - Part 2: Specification for Modbus serial link interoperability test

IEC 60028 International Standard of Resistance for Copper

IEC 60417 Graphical Symbols for Use on Equipment

IEC 60664-4:2005 Insulation arrangements for low-voltage electrical equipment - Part 4: Lisulation Coordination Ordination for Equipment within Low-voltage Systems Part 4: Considerations of High-frequency Voltage Stress

IEC 60695-2-20:2004 Fire hazard testing - Part 2-20: Basic test methods based on glow/hot wire - Test methods and guidelines for hot wire ignition test equipment (Fire Hazard Testing Part 2-20: Glowing/ Hot Wire Based Test Methods Hot-wire Coil Ignitability Apparatus, Test Method and Guidance

General Requirements for Residual Current Operated Protective Devices (IEC 60755)

IEC 60950-1:2005 Information technology equipment safety - Part 1: General requirements (Informstion Technology Equipment - Safety Part 1: General Requirements)

IEC 60990 Method of Measurement of Touch Current and Protective Conductor Current

IEC 61032 uses Protection of Persons and Equipment by Enclosures-probes for Verification (Protection of Persons and Equipment by Enclosures-probes for Verification)

IEC 61180-1:1992 High-voltage test techniques for low-voltage equipment - Part 1: Definitions, tests and procedural requirements (High-voltage Test Techniques for Low-voltage Equipment Part 1: Definitions, Test and Procedure Requirements)

ISO 178-2010 Plastics - Determination of flexural properties (Plastics - Detennination of Flexural Properties)

ISO 179-1-2010 Plastics - Determination of pendulum impact properties - Part 1: Non-instrumented Impact Test (Plastics Determination of Charpy Impact Properties Part 1: Non-instrumented Impact Test)

ISO 180-2010 Plastics - Determination of Izod Impact Strength (Plastics--Determination of Lzod Impact Strength)

ISO 3864-1 Graphic Symbols Safety Colours and Safety Markings Part 1: Design Principles for Safety Signs and Safety Markings in the Workplace and Public Domains (Graphical Symbols--Safety Colors and Safety Signs Part 1: Design Principles for Safety Signs and Safety Markings)

ISO 4892-1 Plastics - Laboratory light source exposure methods - Part 1: General principles (Plastics - Exposure to Laboratory Light Source Part 1: General Guidance)

ISO 4892-2 Plastics - Laboratory light source exposure methods - Part 2: X-ray arc lamps (Plastics - Exposure to Laboratory Light Sources Part 2: Xenon-arc Lamps)

ISO 4892-4 Plastics - Laboratory light source exposure methods - Part 4: Open-air carbon arc lamps (Plastics - Exposure to Laboratory Light Sources Part 4: Open-flame Carbon-arc Lamps)

ISO 527-1-2012 Plastics - Determination of tensile properties - Part 1: General principles (Plastics - Oetermination of Tensile Properties Part 1: General Principles)

ISO 7000 Equipment Graphical Symbols and Lists (Graphical Symbols for Use on Equipment - Index and Synopsis)

ISO 8256-2004 Plastics - Determination of impact strength (Plastics - determination of Tensile-impact Strength)

EN 50530-2010 Integrated Efficiency of Photovoltaic Inverters for Grid-connected PV Inverters

3 Terms and Definitions

3.1

Photovoltaic grid-connected inverter photovoltaic grid-connected inverter

The equipment that converts the DC power from the PV array into AC power and feeds it into the grid.

Note 1: The inverters mentioned in this standard refer to photovoltaic grid-connected inverters.

Note 2: The technical requirements and test methods specified in this standard are not applicable to inverters in AC MODULE.

3.2

Photovoltaic array simulator

A power source that simulates the static and dynamic current and voltage characteristics of a photovoltaic array.

3.3

Inverter AC output terminal inverter AC output terminal

The connection point of the external output power on the AC side of the inverter.

3.4

Maximum power point tracking; MPPT

The output voltage and current changes caused by changes in the surface temperature of the photovoltaic array and the change in the solar illuminance are tracked and controlled so that the array is kept at the maximum output state to obtain the maximum power output automatic adjustment behavior.

3.8

Islanding islanding

When the power grid loses voltage, the photovoltaic system maintains the state of power supply to a portion of the missing piezoelectric network.

3.9

Anti-islanding

A function that prohibits the islanding effect.

Note: When the unplanned islanding effect occurs, due to the unknown status of the system power supply, the following adverse effects will be caused: it may endanger the life safety of maintenance personnel and users of the power grid lines; interfere with the normal closing of the grid; the grid cannot control the voltage and frequency in isolated islands. , thereby damaging the distribution equipment and user equipment.

3.10

Grid simulated power AC simulated power

The test power supply used to simulate the public power grid has adjustable output voltage and frequency.

3.13

Clearance Clearance

The shortest spatial distance between two conductive parts.

3.14

Closed electrical operating area

Room or area where the electrical equipment is used. There is a clear warning sign in this area. Only personnel with relevant skills or specially trained personnel are allowed to enter, and the door or the barrier must be opened with a key or tool before entering.

3.15

Creepage distance

The shortest distance between two conductive parts along the surface of the insulating material.

3.16

Enclosure

Encloses internal components to prevent external influences, flame spread, and dangerous parts of the equipment.

3.17

Fire enclosure

Encloses internal components and minimizes the components of the internal flame and the spread of combustion.

3.18

Electrical protective enclosure

Enclose the internal components and limit the parts of the equipment that reach areas that are at risk of electrical shock, energy, or burns.

3.19

Pollution degree

With a digital rating, the micro-environment within or around the equipment is expected to be contaminated.

3.20

Live parts

Conductors or conductive parts that are energized during normal use, including neutral conductors, but do not routinely include protective neutral (PEN) conductors.

Note: This part does not necessarily include a shock hazard.

3.21

Sample test

A random number of samples are taken from a batch of products for testing.

3.22

Type test light pe test

A test performed on one or more devices manufactured to a design to demonstrate that the device design meets certain specifications.

3.23

Working voltage

The maximum effective value of the AC voltage or DC voltage that may be generated across any particular insulation of the equipment at the rated voltage.

Note: Instantaneous phenomena are not considered. Both open circuit and normal operation must be considered.

3.24

Basic insulation basic insulation

Insulation for basic protection against electric shock under non-fault conditions.

Note: Does not apply to insulation intended for functional purposes.

3.25

Double insulated double insulation

Insulation consisting of both basic insulation and supplementary insulation.

3.26

Reinforced insulation reinforced insulation

A single insulation system added to a live part provides a level of protection against electric shock equivalent to double insulation under specified conditions.

Note: A single insulation system does not mean that the insulation must be a homogeneous substance. It can be composed of multiple insulation layers, but it cannot be tested by dividing it into basic insulation or additional insulation layer by layer.

3.27

Additional insulation supplementary insulauon

In addition to the basic insulation used for fault protection, separate insulation is provided.

3.28

Transient overvoltage transient overvoltage

Oscillating or non-oscillating, usually high damping durations are only a few milliseconds or less overvoltage.

3.29

Protection class I protecuve class I

Electrical shock is prevented by the basic insulation and the protective earthing of the accessible conductive parts, so that the contactable conductor cannot be charged when the basic insulation fails.

3.30

Protection class II protective class II

Not only the basic insulation to prevent electric shock, but also provides additional safety precautions such as double insulation or reinforced insulation. This protection does not rely on protective grounding nor on installation conditions.

3.31

Protection class III protective class III

Devices that prevent electric shock by limiting voltage levels and do not generate dangerous voltages themselves.

Note: For Class III protection equipment, although there is no requirement to prevent electric shock, it applies to all other requirements of this standard.

3.32

Basic protection

Electrical shock protection without fault conditions.

Note: For low-voltage devices, systems and equipment, the basic protection generally corresponds to the direct contact protection specified in GB 16895.21-2011.

3.33

Uniform field homogenous field

The voltage gradient between the electrodes is a substantially constant electric field (a uniform electric field). For example, the electric field of each ball between two balls is greater than the distance between them.

Note: The uniform electric field condition is called Case B.

3.34

Inhomogeneous electric field

The voltage gradient between the electrodes is a substantially non-constant electric field (a non-uniform electric field).

Note: With respect to voltage withstand capability, the non-uniform electric field condition of the tip versus the planar electrode structure is the worst case and is called Case A. It can be represented by a 30 m dot electrode and a 1 m x 1 m planar electrode.

3.35

Temporary overvoltage

Power frequency overvoltage that lasts for a relatively long time (relative to transient overvoltage).

4 inverter type

4.1 Classifying the number of output phases according to the AC side

According to the output side of the AC side can be divided into:

- Single-phase inverters;

- Three-phase inverter.

4.2 According to the installation environment

According to the installation environment can be divided into:

- Indoor type I (with temperature adjustment device);

- Indoor Type II (without temperature adjustment device);

- Outdoor type.

4.3 Classified by electrical isolation

According to electrical isolation can be divided into:

- Isolated;

- Non-isolated.

4.4 Classification by Application

According to the application can be divided into:

- Household type;

- Industrial type (such as power plants, factories, etc.).

4.5 Classified by usage scale

According to the scale of use can be divided into:

电站 Power station type grid-connected inverters (not less than 1MW power station);

- Non-power grid-connected inverters.

4.6 Other classifications

Other types not stated above that are stated by the manufacturer.

5 Inverter identification and data

5.1 Identification

5.1.1 General requirements

a) In addition to the identification of internal components, all markings shall be visible from the outside after installation; the markings for the entire product shall not be placed on parts that can be removed by the operator without tools.

b) Logos may use graphic symbols provided that they comply with the relevant requirements of A.1 or GB/T 5465.2-2008. The documentation provided by the inverter should explain the graphical symbols used.

c) The inverter should at least permanently mark the following:

1) The name or trademark of the manufacturer or supplier;

2) Used to identify the model or name of the inverter;

3) The serial number, code or other identification used to identify the origin, batch or date. Lots or dates are accurate to within 3 months, and the method of date identification does not show duplicate figures for 30 years.

The compliance of this article is verified by inspection.

5.1.2 Inverter Rated Parameters

Unless otherwise specified in this standard, the following applicable parameters shall be marked on the inverter:

- input voltage range, voltage type, and maximum input current;

- output voltage level, voltage type, frequency, maximum continuous operating current, and rated power of the AC output;

- IP protection level.

The compliance of this article is verified by inspection.

5.1.3 Inverter Components and Interfaces

5.1.3.1 Fuse identification

a) The fuse identification should give its rated current. If the fuse base can be fitted with fuses of different voltage levels, the marking should also give its rated voltage. The marking should be close to the fuse or fuse base, or marked directly on the fuse base. It can also be marked in other positions, but it is necessary to clearly distinguish the fuses to which the marks refer.

b) If it is necessary to use fuses with specific fuse characteristics (eg delay time and breaking capacity), the fuse type should be indicated.

c) For fuses installed outside the operator contact area, and in the operator contact area but fixedly welded fuses, only a specific reference symbol (eg FU1, FU2, etc.) may be marked and shall be in the service manual. Explain the relevant information.

5.1.3.2 Switchgear

The opening and closing position of the switchgear must be clearly marked. If the power supply adopts a push-button switch, the 10th or 16th symbol in Table A.1 can be used to mark the position of “ON”, and the 11th or 17th symbol in Table A.1 is used to mark “OFF”. position. These symbols need to be used in pairs, ie the 10th and 11th symbols in Table A.1, or the 16th and 17th symbols.

5.1.3.3 Interface Identification

a) If safety is necessary, instructions should be given for terminals, connectors, controls, and indicators and their various positions, including coolant filling and cable connections (if applicable). You can refer to the symbols given in Table A.1; if the position is not enough, you can use the ninth symbol in Table A.1.

Note: There are multiple pins for signal, control and communication connectors. It is not necessary to label each pin, but only the use of the entire connector.

b) On the buttons and brakes of the emergency brake device, the indicator light used to warn the danger or indicate that emergency treatment is required shall be used in red.

c) Multi-voltage supply inverters must be marked with the factory-set voltage. The logo allows the use of paper labels or other non-permanent materials.

d) The polarity of the connection must be clearly marked on the DC terminal of the inverter:

1) "+" indicates positive electrode, "-" indicates negative electrode;

2) Other graphic symbols that accurately describe the polarity.

e) The connection terminals of the protective earth conductor are marked as follows:

1) The 7th symbol in Table A.1;

2) The letter "PE";

3) Yellow-green two-color wire.

5.1.4 Durability of the logo

This clause requires that the markings on the inverter must be clearly identifiable under normal conditions of use and that it should be able to withstand the corrosion of the cleaning agent specified by the manufacturer.

The compliance of this article is verified by inspections and durability tests on the exterior of the inverter. Using a cloth impregnated with the designated cleaning agent, quickly wipe the label 15s manually with normal pressure (approx. 10N). If the manufacturer does not specify a cleaning agent, replace it with acetone. After wiping, the logo must remain legible, and the attached label must not be loose or curled.

5.2 Documentation

5.2.1 General requirements

a) The documentation should explain the safe operation and installation of the inverter; if necessary, the inverter maintenance instructions and the following contents can also be given:

1) Explain the identification on the inverter, including the symbols used.

2) Position and function of terminals and controllers.

3) All parameters and specifications related to the safe installation and operation of the inverter, including the following environmental parameters, and their meaning and effect:

- Environmental classification;

- Classification of wet places;

——preset the pollution level of the external environment;

- IP protection level;

- ambient temperature and relative humidity;

- Overvoltage category for each input and output port.

4) Warning that the photovoltaic matrix is ​​illuminated and the DC voltage is input to the inverter.

b) Installation instructions, operating instructions, maintenance instructions, etc. Safety-related documentation should be prepared using the universal language of the inverter.

c) Documents must be printed and supplied with the inverter.

Note: Electronic versions of documents can be provided with printed documents, but they cannot replace printed documents.

5.2.2 Installation Instructions

The documentation must include installation instructions, as well as detailed commissioning instructions. For safety reasons, warnings must be given as to the dangers that may occur during installation and commissioning. The information provided by the documentation should include:

a) requirements for assembly, positioning and fixing;

b) the parameters and connection methods of each power supply, the requirements for wiring, external controllers, wire color codes, disconnection methods, and required over-current protection, and instructions as to where the installation location must not interfere with the disconnection of the power supply;

c) parameters and connection methods for each output of the inverter, as well as requirements for wiring, external controllers, wire color codes and required over-current protection;

d) ventilation requirements;

e) special maintenance requirements such as coolant requirements (where applicable);

f) noise level related instructions and instructions;

g) Description of protective grounding.

5.2.3 Operation Instructions

The operating instructions should include all necessary information to ensure safe operation, including the following applicable content:

a) Description of controller settings, adjustment methods, and adjustment effects;

b) instructions for connecting accessories and other equipment, and clearly applicable accessories, removable parts and special materials;

c) warnings of the danger of burns and measures to reduce the risk required by the operator;

d) Indication that the protection measures may be invalid if the inverter is used in a manner not specified by the manufacturer.

5.2.4 Maintenance Instructions

a) The maintenance instructions include the following information:

1) Regular maintenance intervals and instructions required to ensure safety (for example, replacement of air filters or regular reinforcement of terminals, etc.);

2) Instructions for the operator contact area (where applicable), including warnings not to enter specific areas of the inverter;

3) The number and description of parts and components make it easy to find parts that can be replaced by the operator;

4) Explain the safe cleaning method (if applicable).

b) If the inverter is powered by multiple channels, the manual shall state the sequence in which the switching devices are disconnected.

6 Use, installation and transportation conditions

6.1 Normal use, installation and transportation conditions

6.1.1 Normal Conditions of Use

6.1.1.1 Ambient air temperature

- Indoor air temperature range of indoor inverter: indoor type I 0 °C +40 °C; indoor type -20 °C +40 °C.

- Outdoor air temperature range of outdoor inverters: a 5 °C ~ +60 °C.

6.1.1.2 Altitude

The altitude of the installation site does not exceed 1000m.

Note: When the altitude is higher than 1000m, the inverter current capacity will be lower than the specified value as the altitude increases; when the altitude is higher than 2000m, the cooling effect of air and the decrease of dielectric strength need to be considered. Inverters operating under this condition shall be designed or used in accordance with the manufacturer's and user's agreement. For abnormal use of altitude, see 6.2.2.2.

6.1.1.3 Atmospheric conditions

6.1.1.3.1 Humidity

——Relative Humidity Range of Indoor Inverters: Indoor Type I 5%-85% without condensation; Indoor Type II 5%-95% without condensation.

- Outdoor inverter relative humidity range: 4% to 100%, with condensation.

At a temperature of +40°C, the relative air humidity does not exceed 50%. Allows higher relative humidity at lower temperatures, up to 100% at +25°C. Special measures should be taken for occasional condensation caused by temperature changes.

6.1.1.3.2 Pollution Level

a) The pollution level is related to the environmental conditions in which the inverter is used.

Note: The micro-environment of the clearance or creepage distance determines the effect on the electrical insulation, not the product's environment to determine its effect. The microscopic environment of the clearance or creepage distance may be better or worse than the product's environment. The micro-environment includes all factors that affect insulation, such as climatic conditions, electromagnetic conditions, and the generation of pollution.

b) For the electrical appliances used in the enclosure or the electrical enclosures with its own enclosure, the pollution level may be selected within the enclosure.

c) In order to facilitate the determination of electrical clearances and creepage distances, the micro-environment can be divided into four levels of pollution.

1) Pollution Level 1: No pollution or only dry, non-conductive pollution.

2) Pollution Level 2: Normally there is only non-conductive pollution, but it is necessary to take into account the temporary conductive pollution caused by accidental condensation.

3) Pollution level 3: Conductive pollution, or dry non-conductive pollution due to condensation becomes conductive pollution.

4) Pollution Level 4: Persistent conductive pollution, eg due to conductive dust or rain and snow.

Outdoor inverters and indoor type II inverters are generally suitable for pollution level 3 environments; indoor type I inverters are generally suitable for pollution level 2 environments. However, other levels of contamination may be considered for special applications and microcosmic environments. For inverters intended for use in a pollution level 4 environment, measures must be taken to reduce the micro-environment pollution level to 1, 2, and 3 levels.

If the inverter itself is contaminated or wet (for example, conductive contaminants from the motor carbon brushes, or condensation from the cooling system), the pollution level in specific areas of the inverter will increase.

6.1.1.4 Impact Vibration

Inverters may be subject to shock and vibration during production, transportation, installation, operation and maintenance. Therefore, reasonable precautions must be taken to avoid damage. Inverters used in normal operation, transportation, etc. can be verified using the method of 8.6.4.

Impact and vibration conditions that inverters can withstand when used in abnormal operating, transportation, etc. environments are under consideration.

6.1.2 Transportation and Storage

If the conditions of transport and storage of the inverter are different from those specified in 6.1, the manufacturer and the user shall reach a special agreement. For inverters of more than 50kg, the marking of the center of gravity of the inverter must be given on the package for ease of transportation and handling.

6.1.3 Installation

The inverter should be installed according to the manufacturer's instructions.

6.2 Abnormal Usage, Installation and Transportation Conditions

6.2.1 General

If the actual operation and use conditions of the inverter are different from the conditions specified in 6.1, the user shall propose the difference between the conditions used in the condition and the standard conditions, and negotiate with the manufacturer for adaptability under the conditions. For transportation and installation conditions, see 6.1.2, 6.1.3.

6.2.2 Abnormal conditions

6.2.2.1 Ambient air temperature

The ambient air temperature is expected to be below -25°C or above +60°C.

6.2.2.2 Elevation

a) When the altitude of the inverter installation site is higher than 1000m, the current capacity will be lower than the specified value because the air is thin and the heat dissipation capacity is affected. Assuming that the temperature of the cooling medium remains constant, Figure 1 shows the curve of current capacity as a function of altitude.

b) The temperature decreases with increasing altitude. According to the climate characteristics of China, the ambient temperature drops by 0.5°C for every 100m above sea level. For current capacity correction of inverters used in high altitude areas, account shall be taken of both the unfavorable factors of decreasing current capacity with increasing altitude and the favorable factors for the decrease of ambient temperature.

c) When the altitude of the inverter installation site is higher than 2000m, it is also necessary to consider the decrease of electrical dielectric strength.

6.2.2.3 Atmospheric conditions

The relative humidity in the place where the inverter is installed is greater than the prescribed value of 6.1.3, or the atmosphere contains excessive amounts of dust, acidic substances, and corrosive gases. If the inverter is installed offshore.

6.2.2.4 Installation Conditions

The inverter is mounted on a mobile device, or on an electrical support member that is in a tilted position for a long or short period of time (for example, on a ship), or the inverter is subjected to abnormal shock or vibration during use.

6.2.2.5 Other conditions

Other abnormal conditions are under consideration.

7 Structure and Performance Requirements

7.1 Structural Materials

7.1.1 Temperature rise

a) Under the action of electricity, the inverter is affected and affected by thermal stress, and its structural safety may be reduced, and at the same time, it may have unfavorable effects on safety. Unusual temperatures can cause dangerous areas where protection is required:

1) Accessible parts that exceed the safe temperature.

2) Parts, parts, insulation, and plastic materials that exceed a specified temperature. The inverter is within its expected service life, and when it is used normally, the electrical, mechanical and other properties may be reduced if this specific temperature is exceeded.

3) Structures and mounting surfaces that exceed a certain temperature. Exceeding this temperature may shorten the expected life of the inverter and its components.

b) Under normal circumstances, if the relevant components of the inverter or its surface temperature does not change more than 1K/h, the inverter is considered to have reached a thermal stability state. At full power conditions, the temperature rise test lasts for a maximum of 7 hours (simulation of daylight conditions). But except if longer tests will make it more dangerous.

c) The effect of temperature on the material and test methods are given in 8.4.2.2.

Note: The temperature rise under normal use conditions may differ from the test value, depending on the installation conditions and the dimensions of the connecting conductors.

7.1.2 UV exposure

The external plastic parts of outdoor inverters are exposed to ultraviolet radiation, and the degree of danger protection should not be less than that specified in Appendix B. Polymer materials need to be evaluated for their resistance to UV radiation and should comply with Appendix B. If the component degradation does not affect the protection it provides, the requirements of this clause may be ignored.

7.1.3 Shell Protection Level

The inverter shall have protective measures for the enclosure to prevent the human body from approaching the dangerous parts in the enclosure and prevent the entry of solid foreign matter and water, so as to avoid adverse effects on the inverter. The inverter can adopt different shell protection measures according to different occasions. The outdoor inverters must meet the IP54 requirements at minimum, and the indoor inverters must meet the IP20 requirements.

7.2 Electric shock protection requirements

7.2.1 Overview

Electric shock protection is a protective measure taken against the foreseeable misuse of the inverter during its intended life, installation, operation and maintenance.

7.2.2 Direct Contact Protection Requirements

7.2.2.1 General requirements

a) Prevent people from coming into direct contact with live parts that cause harm to people. Measures to prevent direct contact should be achieved by one or more of the measures specified in 7.2.2.2 or 7.2.2.3.

b) Open parts and devices do not require direct contact protection. However, the operating instructions must explicitly require the final product to provide the necessary protective measures after installation.

c) Inverters scheduled to be installed in closed electrical operating areas do not require direct contact protection. If maintenance personnel need to energize the inverter during installation or maintenance, protective measures must comply with the requirements of 7.2.2.2.3.

7.2.2.2 Shell and Barrier Protection

7.2.2.2.1 General requirements

Provide a protective shell and security barrier, and its components should not be removed without the use of tools. Polymer materials that meet these requirements should meet the requirements of 7.1.1 and 7.4 at the same time. When the inverter is used outdoors, the outer shell polymer material must meet the requirements of 7.1.2 when it is exposed to sunlight.

7.2.2.2.2 Preventing Contact Requirements

a) After passing through the enclosure and safety protection, the distance between people and live parts must meet the following requirements:

1) The voltage of live parts is less than or equal to the specified safety voltage - it can be touched;

2) The voltage of the live parts is greater than the specified safety voltage - not accessible, and there must be sufficient clearance between the live parts and the parts, ie, the basic insulation clearance requirements determined by the repeated peak operating voltage of the circuit under consideration.

Note: The provisions of safety voltage limits in accordance with the provisions of GB/T 3805-2008.

b) If the inverter is protected by enclosures or barriers, the minimum IPXXB (also IP2X) degree of enclosure protection as specified in GB 4208-2008 shall be used to carry out the inspection in accordance with 8.2.3.1 to prevent the dangerous liveness from being touched. section.

7.2.2.2.3 Maintenance personnel contact area

If the enclosure needs to be opened during installation or maintenance, and the inverter needs to be powered, it may be inadvertently touched in the course of maintenance.

The live parts of the voltage should provide protection against contact. Protection requirements are inspected in accordance with 8.2.3.1.

7.2.2.3 Insulation protection of live parts

Insulation should be determined according to the inverter's surge voltage, temporary overvoltage or operating voltage, and select the most severe condition according to the requirements of 7.2.4. The insulation protection should not be removed without the use of tools.

7.2.3 Indirect Contact Protection Requirements

7.2.3.1 General requirements

a) In the event of an insulation failure, in order to prevent contact with an electric current that presents a risk of electric shock, indirect contact protection is required. Indirect contact

There are generally three ways to protect:

Protection class I - basic insulation and protective grounding;

Protection class II - double insulation or reinforced insulation;

Protection class III - voltage limits.

b) If the indirect contact protection depends on the installation method, the installation instructions must clearly indicate the relevant hazard and specify the installation method.

c) Circuits that are insulated by indirect protection shall be protected according to 7.2.4.

d) Circuits with a voltage less than the specified safety voltage [see 7.2.2.2.2 a)) have no risk of electric shock.

7.2.3.2 Ground Protection Connection Requirements

7.2.3.2.1 General requirements

a) When the live parts and contactable conductive parts are connected incorrectly, the corresponding protective connection should be able to withstand the maximum thermal stress and dynamic stress caused thereby. The protective connection shall also remain valid in the event of a failure of accessible conductive parts, unless the protective device of the preceding stage cuts off the power supply of that part.

b) The inverter provides a protective connection and ensures that the conductors are accessible to the electrical connection to the external ground protection. Figure 2 shows an example of an inverter and its associated protection connections.

7.2.3.2.2 Connection method

a) The electrical grounding protection connection of the inverter should choose the following method:

1) through a direct metal connection;

2) Connect other components that will not be removed when using the inverter;

3) Through a dedicated protection connection;

4) Connect with other metal components of the inverter.

b) Two parts of direct metal connection. When there is coating or paint at the contact, the coating or paint shall be scraped to ensure the direct contact between metal and metal.

c) When the electrical inverter is mounted on a cover, door or cover, for example, special connection conductors, fasteners, hinges may be used to ensure the continuity of the protection connection, and the impedance thereof needs to meet the requirements of 7.2.3.2.3.

d) Metallic hoses or rigid tubes and metal sleeves generally cannot be used as protective conductors, unless these devices or materials have been shown to be suitable for protective attachment.

7.2.3.2.3 Protection connection requirements

The protection connection should meet the following requirements:

a) For inverters whose rated current of the overcurrent protection device is less than or equal to 16A, the value of the protection connection shall not exceed 0.1 Ω.

b) For inverters with an overcurrent protection device rated greater than 16A in the circuit, the voltage drop across the protective connection shall not exceed 2.5V.

Protective connection measurement and inspection see 8.2.3.2.

7.2.3.3 External Protection Ground Connection Requirements

7.2.3.3.1 General requirements

逆变器通电后外部保护接地导体应始终保持连接。除非当地的配线设计规则有不同要求，否则外部保护接地导体的横截面积需符合表1的要求，或者根据GB 16895.3-2004进行计算。

7.2.3.3.2连接方式

a)每个预定需通过保护连接与地相连的逆变器，都需在靠近相应保护连接导体的地方提供一个连接端子。这个连接端子需进行防腐蚀处理，并且符合7.2.3.3.1的规定。

b）外部保护接地导体的连接方式不能用作其他连接的机械组件。

c）每个外部保护接地导体应使用单独的连接方式。

d）连接点的电流容量不能因机械、化学或电化学影响而降低。若外壳和导体采用铝或铝合金，需特别注意电解液腐蚀的问题。

e）接地回路中不应安装熔断器等短路保护开关装置。

7.2.3.3.3接触电流

为了在保护接地导体受损或被断开的情况下保持安全，对于插头连接的逆变器，使用GB/T 12113-

2003试验图4所规定的试验电路，测得的接触电流不应超过3.5mAAC或10mA DC。

注1:GB/T 12113-2003试验图4参见附录C。

注2：注意外部试验源和地之间的电容对接触电流测量的影响。

对于所有其他逆变器或根据以上要求测量接触电流（见8.2.3.3)，可采用以下一个或多个保护措施：

a）固定连接：

1)保护接地导体的横截面积至少为10mm2（铜）或16mm2（铝）；

2）在保护接地导体中断情况下自动断开电源；

3）有二次保护接地要求的须在安装说明书中注明，且采用的二次保护接地导体的截面积须与一次保护接地导体的截面积相同，并提供另外的接地端。

b)用IEC 60309-1:2005规定的工业连接器进行连接，而且多导体电缆中保护接地导体的最小横截面积为2.5mm2。

7.2.4绝缘配合

7.2.4.1一般要求

根据逆变器的使用及其周围的环境来确定其电气特性。

只有基于在其期望寿命中所承受的应力（如电压）时才能实现的绝缘配合。

7.2.4.2污染等级

逆变器的绝缘在使用期间会受到污染的影响，尤其是通过电气间隙的空气绝缘和爬电距离的固体绝缘。逆变器需满足的最低污染等级应根据6.1.1.3.2的要求确定。

7.2.4.3过电压

7.2.4.3.1概述

过电压类别按GB/T 16895.10-2010中443条款判别：

——类别Ⅳ的设备是使用在配电装置电源中的设备。

注：此类设备包含如测量仪和前级过电流保护设备。

——类别Ⅲ的设备是固定式配电装置中的设备，以及设备的可靠性和适用性必须符合特殊要求者。

注：此类设备包含如安装在固定式配电装置中的开关电器和永久连接至固定式配电装置的工业用设备。

——类别Ⅱ的设备是由固定式配电装置供电的耗能设备。

注：此类设备包含如器具、可移动式工具及其他家用和类似用途负载。如果对此类设备的可靠性和适用性有特殊要求时，则采用过电压类别Ⅲ。

——类别Ⅰ的设备是连接至具有限制瞬时过电压至相当低水平措施的电路的设备。

注：除非电路设计时考虑了暂时过电压，否则过电压类别为Ⅰ的设备不能直接连接于电网中。

7.2.4.3.2 PV电路过电压

一般情况下，Pv电路的过电压等级定为Ⅱ级，冲击耐压分级依据Pv系统电压见表20 PV电路冲击耐压不小于2500V。

7.2.4.3.3电源电路过电压

一般情况下，电源电路过电压考虑等级为Ⅲ级，冲击耐压见表2。

注：电源电路过电压等级不一定为m级，某些安装环境需要考虑W级过电压。逆变器提供的安装信息需说明过电压等级。

7.2.4.4绝缘位置

7.2.4.4.1电路与其周边电路之间

电路及其周边电路之间的基本绝缘、附加绝缘和加强绝缘的设计需考虑以下因素：

——冲击电压；

——暂时过电压；

——电路的额定工作电压。

7.2.4.4.2直接连接电网的电路

直接连接到电网的电路及其周边电路之间的电气间隙和固体绝缘应根据冲击电压、暂时过电压或工作电压进行设计，选择三者中要求最严酷的。

7.2.4.4.3主电路以外的电路

a）两个电路之间的绝缘设计应根据对绝缘有较高要求的电路来确定。对于电气间隙和固体绝缘，由有较高冲击电压要求的电路决定。对于爬电距离，由有较高的工作电压有效值的电路决定。

b）主电路以外的电路及其周边电路之间的电气间隙和固体绝缘，需根据冲击电压和重复峰值电压进行设计，并考虑以下要求：

——系统电压：对于Pv电路，取最大额定Pv开路电压；对于其他电路，取工作电压。

——冲击电压见表2，根据上述系统电压和7.2.4.3规定的过电压等级查表确定。

——电气间隙的设计根据工作电压或冲击电压来确定，取二者中要求较严酷的。

7.2.4.5绝缘材料

绝缘材料应符合GB/T 16935.1-2008中4.8的要求。

将绝缘材料按相比电痕化指数CTi值划分为4组，CTi值是根据GB/T 4207使用溶液A测得的。具体的分组如下：

——绝缘材料组别Ⅰ CTI≥600;

——绝缘材料组别Ⅱ CTI≥400;

——绝缘材料组别Ⅲa CTI≥175;

——绝缘材料组别Ⅲb CTI≥100。

绝缘材料可用耐电痕化指数（PTI）来表明耐电痕化性能。根据GB/T 4207规定的方法使用溶液A验证PTI值。

按GB/T 4207中相比电痕化指数（CTi）试验比较各种绝缘材料在试验条件下的性能，可进行定性比较，同时就绝缘材料具有形成漏电痕迹的趋向来说，相比电痕化指数试验也可进行定量比较。

玻璃、陶瓷或其他无机绝缘材料不会发生电痕化，爬电距离无需大于其相应的为实现绝缘配合而要求的电气间隙。

7.2.4.6电气间隙

7.2.4.6.1概述

电气间隙除考虑7.2.4.2要求外，还需考虑如下影响因素：

——电场条件；

——功能绝缘、基本绝缘、附件绝缘和加强绝缘的冲击耐受电压要求；

——海拔。

7.2.4.6.2电场条件

7.2.4.6.2.1概述

导电部件（电极）的形状和布置会影响电场的均匀性，进而影响耐受规定的电压所需要的电气间隙。

7.2.4.6.2.2非均匀电场条件

由于不能控制形状结构，可能会对电场的均匀性产生不利影响，因此通过绝缘材料外壳缝隙的电气间隙应不小于非均匀电场条件规定的电气间隙。

表3为非均匀电场的电气间隙，选用不小于表3所列的电气间隙可不必考虑导电部件的形状结构，也不必用电压耐受试验进行验证。

用在海拔2000m-20000m的逆变器，电气间隙需根据GB/T 16935.1-2008表A.2（参见附录D)的修正因子进行修正。

电气间隙的符合性应通过测量来验证；必要时需进行8.2.3.4的冲击耐压试验和绝缘耐压试验。

7.2.4.6.2.3均匀电场条件

只有当导电部件（电极）的形状结构设计成使该处电场强度基本上为恒定的电压梯度时才能认为电场均匀。如果确定电场是均匀分布的，而且冲击电压大于或等于6000V（对于直接连接电网的电路）或4000V（电路内部），那么电气间隙可以减小到GB/T 16935.1-2008表E2中情况B的电气间隙值。

7.2.4.6.3功能绝缘的电气间隙的确定

要求耐受电压是逆变器在额定条件下跨电气间隙两端预期发生的最大冲击电压或暂时过电压（见表2)，对应的电气间隙见表3。

7.2.4.6.4基本绝缘、附加绝缘和加强绝缘的电气间隙的确定

基本绝缘和附加绝缘的电气间隙按表3的第2.3列确定。

加强绝缘的电气间隙按表3的第1列确定。对应的电压值应以下一个更高的脉冲电压，或者1.6倍的暂时过电压，或1.6倍的工作电压为最高电压值。

7.2.4.6.5æµ·æ‹”

表3中规定的非均匀电场的电气间隙对从海平面至海拔2000m均有效，附录D规定的海拔修正系数适合于海拔高于2000m的电气间隙。

7.2.4.7爬电距离

7.2.4.7.1概述

a)爬电距离要足够大以防止固体绝缘表面长期退化。对于功能绝缘、基本绝缘和附加绝缘，直接采用表4中的数值。对于加强绝缘表4中数值要加倍。

b)当表4规定的爬电距离小于7.2.4.6规定的或由冲击试验确定的电气间隙时，爬电距离要增加到与电气间隙相同。

c)表4中的值适用于大多数情况，爬电距离应从表4中选取，且必须考虑以下影响因素：

——电压；

——污染；

——爬电距离的方向和位置；

——绝缘表面的形状；

——绝缘材料。

爬电距离通过测量检验，测试方法见8.2.3.4.7。

7.2.4.7.2电压

确定爬电距离是以作用在跨接爬电距离两端的长期电压有效值为基础的。电压见表4中的第1列，允许插值。

7.2.4.7.3污染

表4中数据已考虑了微观环境污染等级对确定爬电距离的影响。

注：逆变器中可能存在不同的微观环境条件。

7.2.4.7.4爬电距离的方向和位置

如有必要，制造商应指明逆变器或元件预期使用的方向和位置，以便在设计时考虑污染的积累对爬电距离的不利影响。

注：必须考虑长期存放的情况。

7.2.4.7.5功能绝缘的爬电距离的确定

功能绝缘的爬电距离应按表4规定的对应于跨接爬电距离两端的实际工作电压确定。

当用实际工作电压来确定爬电距离时，允许用插入值确定中间电压的爬电距离。应使用线性插入法求插入值，并将所得值的位数保留到与表4中数值相同的有效位数。

7.2.4.7.6基本绝缘、附加绝缘和加强绝缘的爬电距离的确定

基本绝缘和附加绝缘的爬电距离应从表4中确定。允许使用插入值确定中间电压的爬电距离。应使用线性插入法求插入值，并将所得值的位数调整到与表中数值相同的位数。

因双重绝缘是由基本绝缘和附加绝缘组成的，故双重绝缘的爬电距离是基本绝缘爬电距离和附加绝缘爬电距离的总和。

加强绝缘的爬电距离应为表4中基本绝缘所确定值的2倍。

7.2.4.8固体绝缘

7.2.4.8.1概述

由于固体绝缘的电气强度远远大于空气的电气强度，故在设计低压绝缘系统时可能不够重视。一方面，通过固体绝缘材料的绝缘距离通常远小于电气间隙而产生高的电应力，另一方面，实际上很少采用高电气强度的材料。在绝缘系统中电极与绝缘之间和不同的绝缘层之间均可能产生间隙，或绝缘材料本身有气隙。在这些间隙或气隙中，即使电压远小于击穿水平，仍可能发生局部放电，这就会影响固体绝缘的使用寿命。

许多不利影响会在固体绝缘的使用寿命期内积累，由此形成复杂的过程，且最终导致绝缘老化。电应力和其他应力（例如热、环境）的叠加会造成绝缘老化。

可用短期试验结合适当的条件处理（见8.6)来模拟固体绝缘的长期性能。

固体绝缘的厚度与其失效机理之间存在一定的联系。固体绝缘的厚度减少，电场强度随之增加，失效的风险也随之上升。由于不可能计算出固体绝缘的所需厚度，因此只能通过试验来验证其性能。

7.2.4.8.2应力

7.2.4.8.2.1电压频率

电压频率会极大地影响电气强度，介质发热和热不稳定性的概率基本与频率成正比。按照GB/T 1408.1-2006，在工频下测量时，厚度为3mm的固体绝缘的击穿电场强度为10kV/mm-40kV/mm。提高施加的电压频率会降低大多数绝缘材料的电气强度。

注：高于30kHz的频率对电气强度的影响见IEC 60664-4:2005.

7.2.4.8.2.2发热

发热可以造成：

——由于内应力的消除造成机械上的变形；

——在高于环境温度（例如温度高于60℃）的较低温升下热塑性材料软化；

——由于塑化剂损失造成某些材料脆裂；

——如果超过材料的玻璃化转变温度，某些交联材料会软化；

——增大介电损耗导致热不稳定性和损坏。

7.2.4.8.2.3机械冲击

如果材料不具有足够的抗撞击强度，机械冲击会造成绝缘损坏。因此，在规定运输、储存、安装和使用的环境条件时要考虑此情况。

7.2.4.8.2.4局部放电（PD)

如果跨在绝缘件上的工作电压重复峰值大于700V且绝缘件上的电压应力大于1kV/mm，要进行局部放电试验。

局部放电特性受外施电压频率的影响。在增高频率的条件下进行加速寿命试验，可证实失效时间基本与外施电压的频率成反比。但实际经验仅包括5kHz及以下的频率，因为在较高的频率下也会存在一些其他的失效机理，如电介质发热。

注：高于30kHz的频率对局部放电的影响见IEC 60664-4:2005。

7.2.4.8.2.5湿度

水蒸气可能会影响绝缘电阻和放电熄灭电压，加剧表面污染，腐蚀外形。对于某些材料，高湿度会大大降低其电气强度。在某些情况下，低湿度也可能是不利的，例如会增大静电电荷的滞留，会降低某些材料（如聚酞胺）的机械强度。

7.2.4.8.2.6其他应力

某些应力的影响不太重要或影响较小，但在特定情况下，还是应引起注意，如：

——紫外线辐射和电离辐射；

——暴露于溶剂或活性化学剂中造成的应力裂纹或应力断裂；

——塑化剂迁移作用；

——霉菌等菌类、细菌的作用；

——机械塑性变形等。

7.2.4.8.3要求

7.2.4.8.3.1概述

基本绝缘、附加绝缘和加强绝缘的固定绝缘应能持久地承受电场强度和机械应力，并能在逆变器的预期寿命期内承受可能产生的热影响和环境影响。

7.2.4.8.3.2耐受电压应力

基本绝缘和附加绝缘应能承受以下试验电压：

a）根据8.2.3.4.2确定冲击电压；

b）根据8.2.3.4.3确定适当的交流或直流电压。

双重或加强绝缘应能承受以下试验电压：

a）根据8.2.3.4.2确定冲击电压；

b）根据8.2.3.4.3确定适当的交流或直流电压；

c）如果跨在绝缘件上的工作电压重复峰值大于700V且绝缘件上的电压应力大于1kV/mm，要进行8.2.3.4.6的局部放电试验。

如果逆变器的试验不能考核元器件或组件内部的双重绝缘或加强绝缘，还应在元器件或组件上进行。

如果元器件符合相关标准并且其制造商有可靠的质量控制体系，那么元器件的抽样试验可以不做。

7.2.4.8.3.3承受机械应力

在预期使用中可能出现的机械振动或冲击不应损坏固体绝缘。

7.2.4.8.3.4承受湿度影响

逆变器在规定湿度条件下应保持绝缘配合。

7.2.4.8.3.5承受其他应力

逆变器可能承受其他应力，这些应力可能会对固体绝缘产生的不利影响正在考虑中。

7.2.5电能危险防护

7.2.5.1危险能量等级的确定

出现下列两种情况之一，则认为存在危险能量等级：

a)电压大于等于2V，且60s之后容量超过240VA。

通过以下试验来检验其符合性：逆变器工作在正常工作条件下，调整连接元器件的可变电阻负载，使输出达到240VA，然后维持60s（适用时，可进一步调整）。如果此时电压大于等于2V，则输出功率处于

危险能量水平，除非过电流保护装置在试验期间动作，或出于某种原因功率不能在240VA下维持60s。

b）电容器电压U大于等于2V，按以下公式计算的电能E超过20J。

7.2.5.2操作人员接触区

逆变器的设计应保证操作人员在接触区内可触及的电路不产生危险能量。

如果两个或更多裸露零部件（其中一个可能接地）之间存在危险能量，它们被金属物体桥接时可能会引起伤害。零部件之间被桥接的可能性通过图E.1规定的试验指来确定。能够被试验指桥接的零部件之间，一定不能存在危险能量。

除了限制能量外，还可提供屏障、护栏和类似的防止无意接触的措施。

7.2.5.3维修人员接触区

位于维修或安装时可能被移动或移除的操作面板中的电容器，逆变器断电之后电容器存储的电荷应不构成危险能量。

逆变器电源断开后，内部的电容器应在lOs内放电至能量低于7.2.5.1规定的2盯。如果由于功能性或其他原因不能满足要求，应在外壳、电容器的保护屏障或电容器附件上清楚地标示表A.1中第21个警告符号及放电时间。在维修手册中也需说明逆变器断电之后电容器放电时间。

本条款的符合性通过检查和测量来验证：检查逆变器和相关电路图；考虑各种情况下断电的可能性，所有开关应分别处于“开”或“关”的位置，逆变器内的周期性耗电装置或元器件应处于非工作状态。

如果不能精确计算电容器的放电时间，则应该进行测量。

7.3机械防护要求

7.3.1通用要求

逆变器不应产生机械危险，棱缘、凸起、拐角、孔洞、护罩和手柄等操作人员能够接触的部位需圆滑、无毛刺，在正常使用时不能引起伤害。

7.3.2运动部件要求

运动部件不能碾压、切割、刺破与之接触的操作人员的身体，也不能严重擦伤操作人员的皮肤。逆变器的危险运动部件需合理布局、封闭安装或加保护罩，为人身提供足够的保护。在例行维护期间，若因技术原因不可避免地要求操作人员接触危险运动部件，例如对运动部件进行调整，则逆变器必须提供以下所有预防措施才允许操作人员接触：

a)只有借助工具才能接触。

b)为操作人员提供的说明书须有声明：操作人员必须经过培训才允许执行危险操作。

c）必须拆卸才能接触到危险部位的盖子或零部件上需有警告标识，以防止未经培训的操作人员误接触。

如果热继电器、过电流保护装置以及自动定时启动装置等，在其复位时产生危险，则逆变器不应加装这些装置；本条款的符合性通过检查来验证，必要时用试验指（见附录E）进行试验，实验要求见8.2.3.1。

试验前先将操作人员可拆卸零部件卸掉，将操作人员可触及的门和盖打开。对于没有采取以上预防措施的逆变器，不允许试验指以不明显力从任何方向触及危险运动部件。对于防止试验指进入的孔洞，需进一步用直的不带关节的试验指，施加30N的力进行试验。如果这种试验指能进入孔洞，则应重新使用新的试验指进行试验；如有必要，则应对该试验指施加至30N的力推入孔洞内。

7.3.3稳定性试验

如果逆变器没有固定到建筑构件上，则在正常使用时其本身须具有物理稳定性。在操作人员打开逆变器的门或抽屉后，逆变器自身需能保持稳定，若不能，则制造商应给出警告标识。

稳定性要求需通过8.2.4.1试验来检验。

7.3.4搬运措施

a）如果逆变器安装搬运手柄，则手柄必须能够承受逆变器本身重力4倍的力。

b)质量为18kg及以上的逆变器或部件，需提供搬运措施，或者在制造商文档中给出搬运指引。

c）对每个手柄施加大小等于逆变器重力4倍的力，不用夹具，直接将力均匀地施加在手柄中间70mm宽的范围内。力要逐渐地增加，10s后达到预定大小，并保

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