IEC 62109-2:2011

Overview

IEC 62109-2:2011 is an international standard developed by the International Electrotechnical Commission (IEC) focusing on the safety of power converters used in photovoltaic (PV) power systems, specifically addressing the particular safety requirements for inverters. This standard supplements IEC 62109-1 and applies to various types of inverters including grid-interactive, stand-alone, and multiple mode inverters. It covers inverters powered by single or multiple PV modules and those used in conjunction with batteries or other energy storage systems.

The purpose of IEC 62109-2 is to ensure the safe design, construction, and operation of inverters to prevent electrical, mechanical, fire, and energy hazards. It sets requirements for testing, marking, documentation, and protective measures, contributing to enhancing performance reliability and user safety in photovoltaic applications worldwide.

Key Topics

• Scope and Applicability
  The standard applies to DC-to-AC inverter products and multifunctional products with inverter functions in PV power systems. It addresses different configurations and environments including grid-connected and off-grid installations.

• Testing Requirements
  Includes general testing and specific tests under single fault conditions, cooling system failures, electrical rating assessments, and performance under various load and fault scenarios. Special emphasis is placed on:

  • Fault tolerance and protection in grid-interactive inverters
  • Load transfer tests for stand-alone inverters
  • Residual current detection and array insulation resistance tests for safety assurance

• Electrical Ratings and Output Quality
  Requirements for output voltage, frequency stability, and waveform quality are detailed, including limits on sinusoidal and non-sinusoidal waveform characteristics based on the inverter’s intended use.

• Protection Against Hazards
  Guidelines for protecting users and equipment from electrical shock, fire, mechanical, chemical, liquid, and sonic pressure hazards. Specific rules apply for inverter backfeed currents, short-circuit protection, and residual current monitoring.

• Marking and Documentation
  Comprehensive instructions for labeling inverter equipment with safety ratings, warnings, and installation information. Documentation must include performance data, fault indicators, firmware version identification, and instructions related to grid interactivity and grounding.

• Environmental and Physical Requirements
  Inverters must meet environmental testing to ensure durability and safety under expected operating conditions. Mechanical and physical protections against hazards are also specified.

Applications

IEC 62109-2:2011 is crucial for manufacturers, installers, and safety inspectors involved in photovoltaic power systems. Its practical applications include:

• Designing and certifying solar inverters that comply with international safety standards.
• Ensuring reliable grid-tied and stand-alone solar power installations with safe operation under normal and fault conditions.
• Supporting energy storage integration with inverters for residential, commercial, and utility-scale solar systems.
• Providing guidelines for system fault detection and safety alarms to protect users and infrastructure.
• Assisting national certification bodies and testing laboratories in carrying out standardized safety evaluations and compliance testing.

Related Standards

• IEC 62109-1:2010 – Safety of power converters for use in photovoltaic power systems – Part 1: General requirements
  Serves as the foundational document combined with Part 2 to cover comprehensive safety aspects of PV power converters.

• IEC 61727 – Photovoltaic (PV) Systems – Characteristics of the utility interface
  Addresses grid-connected inverter requirements related to grid interface and system performance.

• IEC 60364 Series – Low-voltage electrical installations
  Provides general electrical safety requirements that complement inverter safety standards.

• IEC 61000 Series – Electromagnetic compatibility (EMC) standards
  Relevant for ensuring inverters meet immunity and emission requirements in PV systems.

By adhering to IEC 62109-2:2011, stakeholders can ensure their photovoltaic inverter systems provide safe, reliable, and efficient power conversion that meets internationally recognized safety protocols, thus supporting the global adoption of solar energy technologies.